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Title: Multiple phenotypes resulting from a mutagenesis screen for pharynx muscle mutations in Caenorhabditis elegans .
Authors: Ferrier A ; Charron A ; Sadozai Y ; Switaj L ; Szutenbach A ; Smith PA
Journal: PLoS One
Year: 2011
Doc ID: WBPaper00040399
Bibliographic Information
Abstract
Matching Sentences
SECTION: results. Phenotype * Number Anterior bulb morphology 18 APH ( anterior pharynx absent ) 5 Pharynx basement membrane defect 11 Short pharynx 20 GFP-expressing cells outside of pharynx 14 Isthmus defect 11 Pha ( pharynx absent ) 1 Pharynx asymmetric 21 Pharynx GFP weak / nearly absent 6 Posterior bulb defect 9 Procorpus defect 29 Pun ( Pharynx unattached ) 7 Thin , cylindrical pharynx 25 * Worm strains may have overlapping phenotypes . doi : 10 . 1371 / journal . pone . [Field: results, subscore: 9.00]
SECTION: introduction. This report describes multiple classes of mutant pharynx phenotypes isolated from an Ethyl Methanesulfonate ( EMS ) mutagenesis screen for larvae with phenotypes such as short pharynx , thin-cylindrical pharynx , non-adherent cells , anterior pharynx absent , pharynx cells outside the basement membrane , and pharynx unattached . [Field: introduction, subscore: 6.00]
SECTION: results. Gene Location Phenotype C26E6 . 6 III : 22 . 34 Body morphology variant C35D10 . 5 III : 22 . 42 Short Pharynx , large head rnp-4 III : 23 . 18 Pharynx asymmetry dcn-1 III : 23 . 19 Body morphology variant M88 . 2 III : 23 . 12 Short Pharynx , Slightly Dpy xbp-1 III : 23 . 70 myo-2 : : GFP expression limited ccdc-55 III : 23 . 72 Pharynx asymmetry wht-3 III : 23 . 79 Short Pharynx , Slightly Dpy doi : 10 . 1371 / journal . pone . [Field: results, subscore: 5.00]
SECTION: results. 10 I : 6 . 41 Pharynx thin and asymmetric hmr-1 I : 6 . 61 Short pharynx rsr-1 I : 7 . 25 Pharynx asymmetry F56G4 . 4 I : 7 . 96 Pharynx asymmetry doi : 10 . 1371 / journal . pone . [Field: results, subscore: 4.00]
SECTION: abstract. We observed over 83 C . elegans lines with distinctive pharyngeal phenotypes in worms surviving to the L1 larval stage , with phenotypes ranging from short pharynx , unattached pharynx , missing cells , asymmetric morphology , and non-adherent pharynx cells . [Field: abstract, subscore: 3.00]
SECTION: discussion. The lack of consistent staining AJM-1 antibody in the pharynx of PAS136 embryos suggests that a disruption to the adherence of one cell to another is contributing to the mutant phenotype , specifically in the pharynx since adherens junction staining in other areas of the embryo is nearly normal . This implies that the allele mutated in PAS136 may be specific to the pharynx , although it is possible that AJM-1 or accessory proteins such as DLG-1 , LET-413 , or HMP-1 are specifically missing pharyngeal enhancers necessary for it issue specific expression1 [ 30 ] . [Field: discussion, subscore: 3.00]
SECTION: introduction. Thus , the initial goal of our mutagenesis screen was to isolate a gene necessary for either all pharynx muscle , or posterior pharynx muscle specification ; however , we instead found phenotypes that ranged from a short pharynx to pharynxes that are barely distinguishable . [Field: introduction, subscore: 3.00]
SECTION: introduction. We observed over 83 C . elegans lines with distinctive pharyngeal phenotypes in worms surviving to the L1 larval stage , with phenotypes ranging from short pharynx , unattached pharynx , missing cells , asymmetric morphology , and non-adherent pharynx cells . [Field: introduction, subscore: 3.00]
SECTION: results. Gene Name Location Phenotype mom-5 I : 4 . 12 Pharynx Unattached blmp-1 I : 4 . 99 Amorphous pharynx sec-8 I : 5 . 04 Compressed isthmus phi-56 I : 5 . 06 Anterior bulb / isthmus merged , long , thin procorpus lam-3 I : 5 . 06 Amorphous pharynx Y52B11A . [Field: results, subscore: 3.00]
SECTION: abstract. We have also identified new alleles of sma-1 , and our screen suggests many genes directing pharynx assembly and structure may be either pharynx specific or less critical in other it issues . [Field: abstract, subscore: 2.00]
SECTION: discussion. Because MH27 stains adherens junctions , which are easily detected in the pharynx , the lack of a pharynx was obvious in the chromosomal deficiency ozDf2 , which deletes pha-4 [ 33 ] . [Field: discussion, subscore: 2.00]
SECTION: discussion. Pharynx Phenotype Screen PLoS ONE | www . plosone . org 8 November 2011 | Volume 6 | Issue 11 | e26594 pha-4 alleles have been isolated in numerous screens ; although most were not designed to isolate pharynx phenotypes specifically . [Field: discussion, subscore: 2.00]
SECTION: discussion. The isolation of pha-2 , pha-3 , and various Eat mutants was facilitated by using an unc-31 genetic background to identify slow growing , starved , and abnormally pumping worms under a dissecting microscope [ 19 ] ; while most pharynx abnormalities will result in slow growth or larval arrest , many genes responsible for these phenotypes are not specific to the pharynx . [Field: discussion, subscore: 2.00]
SECTION: discussion. A genetic screen optimized for rapid identification of pharynx mutant phenotypes The genetic screen described in this paper was unique in the approach to observing pharynx morphology phenotypes . [Field: discussion, subscore: 2.00]
SECTION: discussion. As expected , myo- 2 : : GFP : : H2B nuclei appear randomly positioned in the mutant pharynx as compared to the wild-type pharynx , consistent with the hypothesis that abnormal morphology and adhesion are the key defects in PAS136 animals . [Field: discussion, subscore: 2.00]
SECTION: discussion. PAS136 mutants are not lacking pharynx muscle cells The C . elegans pharynx is made up of exactly twenty muscle cells with 37 distinct nuclei as a result of the fusion of adjacent cells in many muscle groups during development [ 4 ] . [Field: discussion, subscore: 2.00]
SECTION: discussion. Since PAS136 appear to only suffer adhesion defects in the pharynx , it is likely the mutation of a gene crucial for pharynx adherens junctions but redundant in those in the hypodermis and other it issues is causing the phenotype . [Field: discussion, subscore: 2.00]
SECTION: discussion. Interestingly , past research has shown that the mor-1 gene also results in the rounded pharynx mouth phenotype seen in many of the short pharynx mutants and is located within the same region on chromosome III as PAS77 [ 21 ] . [Field: discussion, subscore: 2.00]
SECTION: discussion. While the short pharynx phenotype was classified as a pharynx that does not undergo proper pharyngeal elongation ; there was variability in the body length among these strains ranging from those with a normal body length to Dpy worms . [Field: discussion, subscore: 2.00]
SECTION: introduction. This report provides an overview of the results of the screen , and focuses on the mapping and PLoS ONE | www . plosone . org 1 November 2011 | Volume 6 | Issue 11 | e26594 00040399 characterization of short pharynx mutants and non-adherent muscle cell pharynx mutants . [Field: introduction, subscore: 2.00]
SECTION: introduction. The ability to use Green Fluorescent Protein ( GFP ) expressed specifically in pharynx muscle of larva has simplified the screening for mutations that affect pharynx structure in live worms . [Field: introduction, subscore: 2.00]
SECTION: introduction. Many previously described pharynx genes have been found using genetic screens , including alleles of genes pha-1 , pha-2 , pha-3 , and pha-4 ; however , these screens were not optimized for screening of morphological changes in pharynx muscle [ 5 , 9 , 19 ] . [Field: introduction, subscore: 2.00]
SECTION: introduction. Interestingly , the posterior sets of pharynx muscle cells derived from the MS blastomere form normally in the absence of TBX-2 and non-muscle ABa derived pharynx does not appear to require TBX-2 function [ 14 ] . [Field: introduction, subscore: 2.00]
SECTION: introduction. Multiple genes have been identified that are expressed in distinct pharyngeal cell types , such as myo-2 and ceh-22 in pharynx muscle and intermediate filaments in marginal cells ; however only tbx-2 is essential to specify a particular cell fate , in this case , anterior ABa derived pharynx muscle cells [ 6 , 14 , 15 , 16 , 17 , 18 ] . [Field: introduction, subscore: 2.00]
SECTION: introduction. In the cases of pha-4 , glp-1 , tbx-35 , and lag-1 , the loss of pharynx cells is not cell-type specific , rather entire regions of the pharynx are deleted such as the anterior ABa derived-pharynx in glp-1 mutants [ 5 , 8 , 10 , 11 , 12 , 13 ] . [Field: introduction, subscore: 2.00]
SECTION: introduction. While less dramatic , mutations in glp-1 , tbx-35 , or lag-1 result in a loss of all pharynx cells derived from ABa or MS lineage , resulting in formation of a half pharynx . [Field: introduction, subscore: 2.00]
SECTION: introduction. If pha-4 expression is eliminated through mutation or RNA interference , the entire pharynx fails to develop ; ectopic expression of pha-4 in early embryos converts additional cells to become pharynx cells [ 5 , 8 ] . [Field: introduction, subscore: 2.00]
SECTION: introduction. For example , eight different classes of pharynx muscle differ in morphology , producing the distinct bilobed pharynx that enables the worm to pump bacteria from the environment and pulverize this food before it passes into the intestine . [Field: introduction, subscore: 2.00]
SECTION: introduction. We have also identified new alleles of sma-1 , and our screen suggests many genes directing pharynx assembly and structure may be either pharynx specific or less critical in other it issues . [Field: introduction, subscore: 2.00]
SECTION: references. Thatcher JD , Fernandez AP , Beaster-Jones L , Haun C , Okkema PG ( 2001 ) The Caenorhabditis elegans peb-1 gene encodes a novel DNA-binding protein Pharynx Phenotype Screen PLoS ONE | www . plosone . org 10 November 2011 | Volume 6 | Issue 11 | e26594 involved in morphogenesis of the pharynx , vulva , and hindgut . [Field: references, subscore: 2.00]
SECTION: results. Other pharynx phenotypes Mutant PAS87 , PAS100 , PAS117 , PAS132 , PAS147 , PAS155 , and PAS197 are among the strains that manifest a tube-like pharynx ( Figure 1C , E , J , and not shown ) . [Field: results, subscore: 2.00]
SECTION: results. Compared to the organized and consistent wild-type pharynx , the nuclei appeared in random locations throughout the mutant pharynx ; however , counts of nuclei showed no significant difference between the numbers of muscle cells seen in the two phenotypes ( n = 19 mutant , n = 9 wild type , p = 0 . 82 ) . [Field: results, subscore: 2.00]
SECTION: results. In wild-type worms , the adherens junctions of the pharynx are clearly discernible from those in the Protein Class Ubiquinol cytochrome c reductase assembly protein RNA-binding protein UBA-like ubiquitin ligase Mitochondrial ribosomal protein bHLH transcription factor Uncharacterized conserved protein ATP-binding cassette ( ABC ) transporter Pharynx Phenotype Screen November 2011 | Volume 6 | Issue 11 | e26594 hypodermis and other areas because of increase intensity at the buccal cavity , metacorpus and terminal bulb in the wild-type worms ( Figure 3F ) ( n = 11 ) . [Field: results, subscore: 2.00]
SECTION: results. 0026594 . t003 PLoS ONE | www . plosone . org 5 Protein Class Frizzled family of seven transmembrane receptors Transcription factor Exocyst complex subunit Signal peptidase subunit Laminin alpha-2 High osmolarity signaling pathway Classical cadherin Splicing co-activator Spliceosomal protein Pharynx Phenotype Screen November 2011 | Volume 6 | Issue 11 | e26594 PAS136 mutants exhibit severe disorganization of the pharynx and appear to have misshapen cells . [Field: results, subscore: 2.00]
SECTION: results. III Short pharynx / thin pharynx PAS252 LG . [Field: results, subscore: 2.00]
SECTION: results. A mutant with pharynx muscle cells that do not appear to adhere PAS136 mutant progeny exhibit pharyngeal disorganization and misshapen cells in both anterior and posterior portions of the pharynx ( Figure 1I ) . [Field: results, subscore: 2.00]
SECTION: results. Complementation analysis of both PAS120 and PAS154 heterozygous worms with the homozygous sma-1 ( e30 ) worms produced 50 % mutant phenotypes in the F1 generation ( n = 99 ) , suggesting these mutant strains represent new sma-1 Pharynx Phenotype Screen PLoS ONE | www . plosone . org 2 November 2011 | Volume 6 | Issue 11 | e26594 Pharynx Phenotype Screen PLoS ONE | www . plosone . org 3 November 2011 | Volume 6 | Issue 11 | e26594 alleles . [Field: results, subscore: 2.00]
SECTION: results. A test of the MH27 adherens junction antibody ( AJM-1 ) staining showed the presence of normal junctions between epithelial cell types in both wild-type embryos and the pharynx of PAS77 embryos , although all regions of the pharynx are shorter in the anterior-posterior orientation ( Figure 2F , G ) . [Field: results, subscore: 2.00]
SECTION: results. Some of these short pharynx mutants were viable to the adult stage , while others died during larval development ; four of the short pharynx stains have been chromosomally mapped ( Table 2 ) . [Field: results, subscore: 2.00]
SECTION: results. In total , we identified 83 possible pharynx defective strains suggestive of abnormalities in cell adhesion , cell fate , cell morphology , and migration in both anterior and posterior pharynx regions ( Table 1 ) . [Field: results, subscore: 2.00]
SECTION: abstract. Our studies have focused on genetically mapping and functionally testing two phenotypes , the short pharynx and the loss of muscle cohesion phenotypes . [Field: abstract, subscore: 1.00]
SECTION: discussion. In contrast , the myo-2 : : GFP strain used in our study fluoresced brightly and provided a very distinctive pharynx shape that could be recognized as wild type of mutant immediately . [Field: discussion, subscore: 1.00]
SECTION: discussion. In both cases , the screens were not targeting detecting diverse pharynx phenotypes . [Field: discussion, subscore: 1.00]
SECTION: discussion. Although alleles of genes such as pha-1 , pha-2 and pha-3 , and pha-4 were found in previous mutagenesis screens ; many of these alleles were isolated in screens that did not focus on pharynx structure [ 5 , 9 , 19 ] . [Field: discussion, subscore: 1.00]
SECTION: discussion. Counting the nuclei using myo-2 : : GFP : : H2B allowed us to determine if the PAS136 mutant worms were missing pharynx muscle cells compared to wild-type worms . [Field: discussion, subscore: 1.00]
SECTION: discussion. These basal domains of the apical junctions are known to regulate adhesion in the pharynx [ 31 ] . [Field: discussion, subscore: 1.00]
SECTION: discussion. Although complementation of PAS136 and lam-3 worms and DNA sequence of the PAS136 lam-3 allele does not support lam-3 as the cause of the disorganized pharynx phenotype ; it is possible another nearby gene involved in extracellular matrix organization may be involved . [Field: discussion, subscore: 1.00]
SECTION: discussion. The PAS136 amorphous pharynx phenotype We hypothesize the extreme disorganization of the pharyngeal muscles and marginal cells of PAS136 homozygous L1 progeny are caused by a mutation in a gene responsible for morphology and cell adhesion . [Field: discussion, subscore: 1.00]
SECTION: discussion. Sequence analysis confirmed PAS154 is a novel allele mutant for bH- spectrin , previously documented alleles of sma-1 share the sma- 1 ( lfc1 ) phenotype of a small body phenotype and short , fat pharynx [ 23 ] . [Field: discussion, subscore: 1.00]
SECTION: discussion. Even more , these mutants were chromosomally mapped to chromosome V . Worms with a loss-of-function mutation for sma-1 manifest a short pharynx phenotype similar to that of PAS120 and PAS154 . [Field: discussion, subscore: 1.00]
SECTION: discussion. The PAS154 mutant phenotype is a result of a new allele of sma-1 Through our forward genetic screen we also isolated two other mutants that exhibit similar short pharynx phenotypes : PAS120 and PAS154 . [Field: discussion, subscore: 1.00]
SECTION: discussion. 0026594 . g004 Pharynx Phenotype Screen PLoS ONE | www . plosone . org 7 November 2011 | Volume 6 | Issue 11 | e26594 For instance , pha-2 mutants ( pha-2 encodes a homeodomain transcription factor protein ) manifest a short isthmus [ 26 ] . [Field: discussion, subscore: 1.00]
SECTION: discussion. ( A ) PAS77 mutant phenotype with poorly defined pharynx regions . [Field: discussion, subscore: 1.00]
SECTION: discussion. Moreover , seeing that the pharynx is essential for the grinding and ingestion of food , it is possible that PAS77 dies due to starvation . [Field: discussion, subscore: 1.00]
SECTION: discussion. Also , PAS77 usually developmentally arrests and dies during the L1 stage of development , because while the overall proportions of the pharynx are consistent , the length is greatly diminished . [Field: discussion, subscore: 1.00]
SECTION: discussion. We analyzed the short pharynx mutant strain PAS77 , which exhibits defects in the metacorpus , procorpus , and manifests a short isthmus . [Field: discussion, subscore: 1.00]
SECTION: discussion. Surprisingly , 20 of the 83 pharyngeal mutants were homozygous recessive mutants that expressed the short pharynx and rounded mouth phenotype . [Field: discussion, subscore: 1.00]
SECTION: introduction. No gene has been found that is specifically required for posterior pharynx muscle specification . [Field: introduction, subscore: 1.00]
SECTION: introduction. The pha-1 gene allows for initial development of pharyngeal precursor cells , but then affects differentiation of all pharynx cells types after the 1K-fold stage of embryogenesis when differentiation markers such as pharyngeal myosin and intermediate filaments are normally activated [ 9 ] . [Field: introduction, subscore: 1.00]
SECTION: introduction. In C . elegans , pha-4 is an organ identity gene involved in the specification and differentiation of all cells destined to become the pharynx [ 5 , 6 , 7 ] . [Field: introduction, subscore: 1.00]
SECTION: introduction. Seven different cell types are specified during pharynx organogenesis ; and within these cell types , sub-specialization occurs producing distinct anterior to posterior characteristics [ 4 ] . [Field: introduction, subscore: 1.00]
SECTION: introduction. The C . elegans pharynx exhibits progressive restriction of cell fate during development , ultimately resulting in the expression of differentiation factors and structural proteins essential to its function as a neuromuscular pump [ 1 , 2 , 3 ] . [Field: introduction, subscore: 1.00]
SECTION: introduction. Citation : Ferrier A , Charron A , Sadozai Y , Switaj L , Szutenbach A , et al . ( 2011 ) Multiple Phenotypes Resulting from a Mutagenesis Screen for Pharynx Muscle Mutations in Caenorhabditis elegans . [Field: introduction, subscore: 1.00]
SECTION: introduction. Our studies have focused on genetically mapping and functionally testing two phenotypes , the short pharynx and the loss of muscle cohesion phenotypes . [Field: introduction, subscore: 1.00]
SECTION: introduction. Multiple Phenotypes Resulting from a Mutagenesis Screen for Pharynx Muscle Mutations in Caenorhabditis elegans Andrew Ferrier , Alexandra Charron , Yama Sadozai , Lynn Switaj , Anneliese Szutenbach , Pliny A . Smith * Biology Department , Lake Forest College , Lake Forest , Illinois , United States of America , Abstract [Field: introduction, subscore: 1.00]
SECTION: materials. Pharynx muscle nuclei counts Nuclearly localized myo-2 : : GFP worms were maintained by microinjecting 0 . 05 ng / mL myo-2 : : GFP : : His2B , 40 ng / ml pRF4 , and 60 ng / ml herring sperm DNA into N2 hermaphrodite and screening for rolling progeny . [Field: materials, subscore: 1.00]
SECTION: materials. Sequence data was assem- Pharynx Phenotype Screen PLoS ONE | www . plosone . org 9 November 2011 | Volume 6 | Issue 11 | e26594 bled into a contig and compared to wild type sequences in WormBase ( wormbase . org ) [ 20 ] . [Field: materials, subscore: 1.00]
SECTION: references. Pharynx Phenotype Screen PLoS ONE | www . plosone . org 11 November 2011 | Volume 6 | Issue 11 | e26594 [Field: references, subscore: 1.00]
SECTION: references. Jafari G , Burghoorn J , Kawano T , Mathew M , Morck C , et al . ( 2010 ) Genetics of extracellular matrix remodeling during organ growth using the Caenorhabditis elegans pharynx model . [Field: references, subscore: 1.00]
SECTION: references. Albertson DG , Thomson JN ( 1976 ) The pharynx of Caenorhabditis elegans . [Field: references, subscore: 1.00]
SECTION: results. The PAS117 , PAS147 , PAS157 , PAS158 , PAS163 , and PAS236 mutant phenotypes show extensive loss of anterior pharynx muscle morphology ( Figure 1E , J , L , M , P , T ) . [Field: results, subscore: 1.00]
SECTION: results. III ; however , some progeny also demonstrated the short pharynx phenotype ( Figure 1V , W ) . [Field: results, subscore: 1.00]
SECTION: results. PAS147 lacks of a distinct anterior bulb , but otherwise has generally symmetric pharynx morphology ( Figure 1J ) . [Field: results, subscore: 1.00]
SECTION: results. However , PAS252 mutant worms with a very similar phenotype did not have beads present in either their pharynx or intestine ( Figure 4C , D ) . [Field: results, subscore: 1.00]
SECTION: results. PAS77 phenotype worms that fed on Fluoresbrite beads for two hours exhibited beads in both their pharynx and intestine , demonstrating their ability to ingest food normally ( Figure 4A , B ) . [Field: results, subscore: 1.00]
SECTION: results. PAS136 mutants have a wild type number of pharynx muscle cells The mutant worms of the PAS136 strains appear to have gaps between muscle cells that are not normally present , which could be the result of some muscle cells not be present at all . [Field: results, subscore: 1.00]
SECTION: results. ( G ) PAS136 embryo with weak and disconnect AJM-1 staining in the pharynx ( ph ) and more normal AJM-1 in the intestine ( it ) . [Field: results, subscore: 1.00]
SECTION: results. ( F ) Wild-type MH27 AJM-1 adherens junction antibody staining showing pharynx ( ph ) and intestine ( it ) localization . [Field: results, subscore: 1.00]
SECTION: results. ( E ) hmr-1 ( W02B9 . 1 ) RNAi results in a Pun phenotype with diminished anterior pharynx cells ( arrow ) . [Field: results, subscore: 1.00]
SECTION: results. ( D ) blmp-1 ( F25D7 . 3 ) RNAi has a less severe PAS136 phenotype ( arrow denotes cell disconnected from the pharynx ) . [Field: results, subscore: 1.00]
SECTION: results. ( B ) pha-4 RNAi used a positive control for pharynx phenotypes , arrow shows lack of myo-2 : : GFP in most of the head . [Field: results, subscore: 1.00]
SECTION: results. ( A ) Probable location of the PAS136 pharynx phenotype allele is between 6 cM and 8 cM on LG . [Field: results, subscore: 1.00]
SECTION: results. PAS136 mapping and pharynx markers . [Field: results, subscore: 1.00]
SECTION: results. ( G ) PAS77 MH27 antibody staining shows four compressed pharynx regions ( arrows ) . [Field: results, subscore: 1.00]
SECTION: results. ( F ) wild-type MH27 AJM-1 adherens junction antibody staining shows four distinct regions in the pharynx ( arrows ) . [Field: results, subscore: 1.00]
SECTION: results. ( E ) xbp-1 ( R74 . 3 ) RNAi eliminates GFP expression in pharynx . [Field: results, subscore: 1.00]
SECTION: results. ( C and D ) C35D10 . 5 RNAi or M88 . 2 RNAi results in a short pharynx phenotype . [Field: results, subscore: 1.00]
SECTION: results. Arrow shows region missing anterior pharynx cells . [Field: results, subscore: 1.00]
SECTION: results. ( A ) Probable location of the PAS77 pharynx phenotype allele is between 24 . 47 cM and 23 . 1 cM relative to the genetic center of LG . [Field: results, subscore: 1.00]
SECTION: results. PAS77 mapping and pharynx markers . [Field: results, subscore: 1.00]
SECTION: results. 0026594 . g001 Pharynx Phenotype Screen PLoS ONE | www . plosone . org 4 November 2011 | Volume 6 | Issue 11 | e26594 Figure 2 . [Field: results, subscore: 1.00]
SECTION: results. ( X ) PAS252 short pharynx . doi : 10 . 1371 / journal . pone . [Field: results, subscore: 1.00]
SECTION: results. ( W ) PAS241 short pharynx . [Field: results, subscore: 1.00]
SECTION: results. ( U ) PAS237 pharynx muscle cells unattached . [Field: results, subscore: 1.00]
SECTION: results. ( R ) PAS196 short pharynx . [Field: results, subscore: 1.00]
SECTION: results. ( P ) PAS163 disorganized pharynx with unattached GFP-expressing cells . [Field: results, subscore: 1.00]
SECTION: results. ( O ) PAS159 short pharynx . [Field: results, subscore: 1.00]
SECTION: results. ( N ) PAS158 Diminished GFP expression and asymmetric anterior pharynx . [Field: results, subscore: 1.00]
SECTION: results. ( L and M ) PAS157 pharynx asymmetry with indistinct isthmus and anterior bulb . [Field: results, subscore: 1.00]
SECTION: results. ( K ) PAS154 short pharynx phenotype . [Field: results, subscore: 1.00]
SECTION: results. ( J ) PAS147 cylindrical pharynx with diminished anterior bulb . [Field: results, subscore: 1.00]
SECTION: results. ( I ) PAS136 pharynx muscle cells do not adhere to each other . [Field: results, subscore: 1.00]
SECTION: results. ( H ) PAS129 short pharynx with head defects . [Field: results, subscore: 1.00]
SECTION: results. ( G ) PAS126 short pharynx . [Field: results, subscore: 1.00]
SECTION: results. ( F ) PAS120 short pharynx and bulbous head . [Field: results, subscore: 1.00]
SECTION: results. ( D ) PAS101 pharynx unattached . [Field: results, subscore: 1.00]
SECTION: results. ( C ) PAS100 thin pharynx with less anterior GFP expression than wild type . [Field: results, subscore: 1.00]
SECTION: results. ( B ) PAS77 short pharynx phenotype . [Field: results, subscore: 1.00]
SECTION: results. X Short pharynx doi : 10 . 1371 / journal . pone . [Field: results, subscore: 1.00]
SECTION: results. X Short pharynx PAS262 LG . [Field: results, subscore: 1.00]
SECTION: results. IV Anterior pharynx defects PAS202 LG . [Field: results, subscore: 1.00]
SECTION: results. IV Short pharynx PAS170 LG . [Field: results, subscore: 1.00]
SECTION: results. I Amorphous pharynx PAS154 LG . [Field: results, subscore: 1.00]
SECTION: results. I Amorphous pharynx PAS138 LG . [Field: results, subscore: 1.00]
SECTION: results. V Thin , cylindrical pharynx PAS136 LG . [Field: results, subscore: 1.00]
SECTION: results. IV Short pharynx PAS132 LG . [Field: results, subscore: 1.00]
SECTION: results. III Short pharynx PAS100 LG . [Field: results, subscore: 1.00]
SECTION: results. Summation of pharynx phenotypes . [Field: results, subscore: 1.00]
SECTION: results. A partially penetrant phenotype similar to that of PAS136 resulted from lam-3 ( T22A3 . 8 ) RNAi and blmp-1 ( F25D7 . 3 ) RNAi ( Figure 3C and D ) ; the laminin gene lam-3 has previously been shown to affect the extracellular matrix and pharynx cohesion , while blmp-1 is described as a homolog of the B lymphocyte-induced maturation protein 1 on WormBase [ 24 , 25 ] . [Field: results, subscore: 1.00]
SECTION: results. Within the region of PAS136 mapping , there are 322 genes ; 39 were chosen for screening using recorded L1 arrest as a necessary parameter ; experiments showing pharynx phenotypes are listed ( Table 4 ) . [Field: results, subscore: 1.00]
SECTION: results. To screen genes in the mapped region as candidates for PAS136 , we used RNAi to screen for phenocopy of the pharynx phenotype with bacterial feeding RNAi using the PD4792 myo- 2 : : GFP reporter strain . [Field: results, subscore: 1.00]
SECTION: results. There are also gaps between pharynx muscle cells , which are not normally present . [Field: results, subscore: 1.00]
SECTION: results. Finally , the PAS241 phenotype results in an extremely wide head and Dpy body with an extremely short pharynx lacking distinct regions ( Figure 1W ) . [Field: results, subscore: 1.00]
SECTION: results. PAS126 , PAS129 , PAS159 , PAS196 , and PAS241 also exhibit the short pharynx phenotype ; although the primary the defect is a failure for the procorpus to elongate ( Figure 1G , H , O , R , W ) . [Field: results, subscore: 1.00]
SECTION: results. V and encodes a spectrin homolog with a similar pharynx phenotype [ 23 ] . [Field: results, subscore: 1.00]
SECTION: results. The strains PAS120 and PAS154 also share the short pharynx phenotype , however , despite their morphological defects , both are viable and fertile as homozygotes ( Figure 1F , K ) . [Field: results, subscore: 1.00]
SECTION: results. The MH4 monoclonal antibody to recognize intermediate filament shows that marginal cells are present , and appear similar to wild type ( Figure 2H ) other than for the compressed shape of the pharynx ( Figure 2I ) . [Field: results, subscore: 1.00]
SECTION: results. While not a PAS77 phenotype , the R74 . 3 ( xpb-1 ) dsRNA bacterial vector resulted in a nearcomplete absence of myo-2 : : GFP without apparent loss of pharynx muscle as seen in DIC imaging ( Figure 2E ) . [Field: results, subscore: 1.00]
SECTION: results. RNAi of M88 . 2 , a mitochondrial ribosomal protein , also produced L1 arrested larvae with a short pharynx phenotype ( Figure 2D ) . [Field: results, subscore: 1.00]
SECTION: results. The C35D10 . 5 RNAi resulted in many embryos with a short pharynx phenotype ; interestingly , C35D10 . 5 encodes a predicted ubiquinol cytochrome c reductase assembly protein ( Figure 2C ) . [Field: results, subscore: 1.00]
SECTION: results. Multiple RNAi bacterial strains resulted in pharynx phenotypes ( Table 3 ) . [Field: results, subscore: 1.00]
SECTION: results. glp-1 was used as a positive control for this experiment because it has a dramatic Anterior Pharynx Defective ( Aph ) phenotype that is easily identified in the PD4792 strain ( Figure 2B ) . [Field: results, subscore: 1.00]
SECTION: results. The short-pharynx phenotypes We identified 20 mutant lines that shared a similar phenotypic trait , a short pharynx and rounded mouth similar to mutant strain PAS77 ; nine are shown in Figure 1 ( Figure 1B , F , G , H , K , O , R , W , X ) . [Field: results, subscore: 1.00]
SECTION: results. Initially , the low-copy number myo-2 : : GFP ( AZ217 ) integrated reporter strain was used in mutagenesis ; however , the strain ' s weak fluorescence made rapid identification of pharynx abnormalities difficult under an epifluorescent stereomicroscope . [Field: results, subscore: 1.00]
SECTION: results. We performed an EMS mutagenesis screen of , 10 , 000 haploid genomes to identify the genes affecting posterior muscle fate in C . elegans , using a myo-2 : : GFP reporter to visualize pharynx morphology in L1s . [Field: results, subscore: 1.00]
SECTION: title. Multiple phenotypes resulting from a mutagenesis screen for pharynx muscle mutations in Caenorhabditis elegans . [Field: title, subscore: 1.00]
Supplemental links/files: reference in endnote reference in xml Wormbase reference
Score: 144.00
Title: The C . elegans pharynx : a model for organogenesis .
Authors: Susan E . Mango
Journal: WormBook
Year: 2007
Doc ID: WBPaper00029033
Bibliographic Information
Abstract
Matching Sentences
SECTION: introduction. Aph : anterior pharynx absent Daf : dauer defective , M / Z : maternal or zygotic contribution of RNA or protein , Pha : pharynx absent , pm : pharyngeal muscle , PPa : posterior pharynx absent , Pun : pharynx unattached , Rcp : receptor , TF : transcription factor , Zn : zinc , ? [Field: introduction, subscore: 4.00]
SECTION: references. Mutants have a misshapen pharynx and sometimes arrest with a Pun ( Pharynx UNattached ) pharynx , however it is unclear if this phenotype represents loss of arcade cell identity or defective morphogenesis ( Yanowitz et al . , 2004 The C . elegans pharynx : a model for organogenesis 12 Hope , 1991 ; 2ng / ul ) were used , as were more likely ; Gaudet et al . , 2004 ) . [Field: references, subscore: 4.00]
SECTION: references. Once connected the pharynx undergoes additional morphogenesis , to The C . elegans pharynx : a model for organogenesis 13 produce the bi-lobed structure of the mature pharynx . [Field: references, subscore: 3.00]
SECTION: introduction. Early control of pharyngeal development-the The pharynx is generated polyclonally during embryogenesis : at the 4-cell stage , two blastomeres , EMS , contribute descendants to the pharynx , whereas their sisters do not ( see 28-cell stage , most early blastomeres are pluripotent and give rise to multiple cell types . [Field: introduction, subscore: 2.00]
SECTION: introduction. Anatomy of the pharynx We have a detailed knowledge of the anatomy of the pharynx , based on ultrastructural studies by Donna Albertson ( Albertson and Thomson , 1976 ) . [Field: introduction, subscore: 2.00]
SECTION: introduction. Third , pharynx development is robust . Embryos with abnormal development in other it issues can still produce a well-differentiated pharynx . [Field: introduction, subscore: 2.00]
SECTION: introduction. The pharynx as a model for organ development Four characteristics of the C . elegans pharynx make it a powerful system to study organogenesis . [Field: introduction, subscore: 2.00]
SECTION: references. First , while the heart is a mesodermal organ , the pharynx appears to be ectodermal . Topologically , the pharynx is connected to the epidermis and , like the epidermis , is lined with cuticle ( Albertson and Thomson , 1976 ) . [Field: references, subscore: 2.00]
SECTION: references. The C . elegans pharynx : a model for organogenesis 16 zen-4 ) , anterior pharynx absent Aph . [Field: references, subscore: 2.00]
SECTION: references. The ceh-43 / distal-less homolog is not obviously expressed in the pharynx but loss of leads to a detached pharynx , possibly because of problems with the epidermal epithelium ( 2001 ) . [Field: references, subscore: 2.00]
SECTION: references. Note the full size but unattached Pun pharynx compared to the smaller than normal Aph pharynx ( arrowhead ) . [Field: references, subscore: 2.00]
SECTION: references. Examples of pharyngeal phenotypes : wild type WT , pharynx unattached Pun ( ( aph-1 ) and pharynx absent Pha ( pha-4 ) . [Field: references, subscore: 2.00]
SECTION: references. The remainder of the pharynx is presumably dragged forward by virtue of its attachment to the anterior pharynx . [Field: references, subscore: 2.00]
SECTION: references. Next , the arcade cells form adherens junctions that link the pharynx and epidermis , to form a continuous epithelium ( see event mechanically couples the buccal cavity to the pharynx and anterior epidermis . [Field: references, subscore: 2.00]
SECTION: references. Downstream of PHA-4 : patterning the pharynx primordium How are individual cell types generated within the pharynx ? [Field: references, subscore: 2.00]
SECTION: abstract. Finally , I discuss similarities and differences between the nematode pharynx and the vertebrate heart . [Field: abstract, subscore: 1.00]
SECTION: abstract. Here I review recent advances regarding cell-fate specification and epithelial morphogenesis during pharynx development . [Field: abstract, subscore: 1.00]
SECTION: abstract. The C . elegans foregut ( pharynx ) has emerged as a powerful system to study organ formation during embryogenesis . [Field: abstract, subscore: 1.00]
SECTION: introduction. The C . elegans pharynx : a model for organogenesis 6 Binding sequence Upstream genes [Field: introduction, subscore: 1.00]
SECTION: introduction. Within ABa-derived cells destined to form the pharynx , initiation of TBX-37 / 38 expression precedes REF-1 activity , which explains why development in this subset of cells . [Field: introduction, subscore: 1.00]
SECTION: introduction. ceh-2 Homeobox ems , EMX Z I3 , NSM , M3 , pm2 , e2 Poor feeding , M3 defective ceh-43 Distal-less homeobox Z Non-pha neurons , epidermis Pun , anterior leakage One of the REF-1 downstream targets , direct or indirect , is a pair of T-box genes called TBX-37 and TBX-38 constitute a pair of closely related , redundant factors that are activated at the 24-cell stage in the eight ABa descendents and required for a subset of these cells to generate pharynx ( restricted expression within these cells depends on repression by REF-1 family genes leads to widespread TBX-37 / 38 in blastomeres that normally would never normally express these genes ( Neves and Priess , 2005 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. Beaster-Jones and Okkema , 2004 ; Thatcher et al . , 2001 daf-12 NHR Zn TF Z Broadly Daf myo-2 ceh-22 AGTGCA daf-9 Ao et al . , 2004 The C . elegans pharynx : a model for organogenesis 5 Gene Homology M / Z Expression ( initiation ) Pha phenotype Targets pha-1 Novel Z Broadly Arrested diffn , loss of TF expression ceh-22 pha-4 pha-2 Homeobox Z Pm5 , I4 , epi pm4 , pm5 , morph ceh-22 ceh-2 ast-1 ETS Z Head Pun ? [Field: introduction, subscore: 1.00]
SECTION: introduction. Chowdhury et al . , 2006 ; Smith and Mango , 2006 ceh-22 Nkx2-5 Homeobox TF Z pm3-5 , pm7 Indistinct BM Around pharynx myo-2 CACTTAT pha-4 ceh-22 ceh-2 pha-2 Kalb et al . , 1998 ; Mango et al . , 1994 ; Okkema and Fire , 1994 ; Okkema et al . , 1997 peb-1 FLYWCH Zn TF Z Broadly Glands distended myo-2 YDTGCCRW ? [Field: introduction, subscore: 1.00]
SECTION: introduction. Genes implicated in pharynx development are listed from earliest stages of specification to later events . [Field: introduction, subscore: 1.00]
SECTION: introduction. Summary of genes involved in pharynx development . [Field: introduction, subscore: 1.00]
SECTION: introduction. The C . elegans pharynx : a model for organogenesis 4 ABa lineage ABa and Figure 3 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. The pharynx is generated polyclonally . [Field: introduction, subscore: 1.00]
SECTION: introduction. The C . elegans pharynx : a model for organogenesis 3 3 . [Field: introduction, subscore: 1.00]
SECTION: introduction. The pharynx is composed of eight layers of muscles ( pm1-8 , green ) separated by structural marginal cells ( mc1-3 , pink ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. Pharynx anatomy . [Field: introduction, subscore: 1.00]
SECTION: introduction. Nuclei within the pharynx ( upper panel ) are shown as red muscles , purple neurons , orange epithelia , pink marginal cells and brown glands . [Field: introduction, subscore: 1.00]
SECTION: introduction. The C . elegans digestive tract is an epithelial tube consisting of the buccal cavity ( lower panel , yellow ) , foregut or pharynx ( green ) , midgut or intestine ( orange ) and hindgut ( blue ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. Nuclei of the pharynx . [Field: introduction, subscore: 1.00]
SECTION: introduction. I define the pharynx as those pha-4 mutants , which includes two additional types of Albertson and Thomson , 1976 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. The C . elegans pharynx : a model for organogenesis 2 Sulston et al . , 1983 ) , making it possible to follow http : / / www . wormbase . org / db / searches / ; Chanal and Labouesse , 1997 ; Mango et al . , 1994 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. Anteriorly , the pharynx attaches to the buccal cavity and exterior epidermis via nine arcade cells and nine epithelial cells , organized into three rings . [Field: introduction, subscore: 1.00]
SECTION: introduction. These criteria identify 95 nuclei that can be subdivided into seven cell types : arcade cells , muscles , epithelia , neurons , glands , marginal cells and valves ( Along the longitudinal axis , there are eight sections of muscles and three sections of marginal cells ; these make up the bulk of the pharynx ( see Figure 2 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. The pharynx is a bilobed , linear tube encased in a basement membrane . [Field: introduction, subscore: 1.00]
SECTION: introduction. For example , the pharynx is composed of cells with different embryonic origins ( Sulston et al . , 1983 ) , similar to the polyclonal origin of most vertebrate organs . [Field: introduction, subscore: 1.00]
SECTION: introduction. Fourth , formation of the pharynx faces similar developmental challenges to those of organs in more complex animals and uses conserved molecular pathways to meet those challenges . [Field: introduction, subscore: 1.00]
SECTION: introduction. This characteristic enables researchers to focus on molecules likely to play a direct role in pharynx formation without the problems associated with indirect effects . [Field: introduction, subscore: 1.00]
SECTION: introduction. For example , an embryo that can not undergo normal morphogenesis arrests as a ball of cells with a differentiated pharynx ( Ahnn and Fire , 1994 Storfer-Glazer and Wood , 1994 ; Terns et al . , 1997 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. In addition , there are antibodies and GFP reporters that mark individual cell types or developmental stages within the pharynx ( expr_search ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. Second , the mature pharynx is simple and well-characterized . [Field: introduction, subscore: 1.00]
SECTION: introduction. Finally , I discuss similarities and differences between the nematode pharynx and the vertebrate heart . [Field: introduction, subscore: 1.00]
SECTION: introduction. Here I review recent advances regarding cell-fate specification and epithelial morphogenesis during pharynx development . [Field: introduction, subscore: 1.00]
SECTION: introduction. The C . elegans foregut ( pharynx ) has emerged as a powerful system to study organ formation during embryogenesis . [Field: introduction, subscore: 1.00]
SECTION: introduction. Is the pharynx a heart ? [Field: introduction, subscore: 1.00]
SECTION: introduction. Downstream of PHA-4 : patterning the pharynx primordium . [Field: introduction, subscore: 1.00]
SECTION: introduction. Anatomy of the pharynx . [Field: introduction, subscore: 1.00]
SECTION: introduction. The pharynx as a model for organ development . [Field: introduction, subscore: 1.00]
SECTION: introduction. E-mail : susan . mango @ hci . utah . edu The C . elegans pharynx : a model for organogenesis * Susan E . Mango , Department of Oncological Sciences , Huntsman Cancer Institute , University of Utah , Salt Lake City , UT 84112 USA Table of Contents 1 . [Field: introduction, subscore: 1.00]
SECTION: introduction. E . The C . elegans pharynx : a model for organogenesis ( January 22 , 2007 ) , WormBook , ed . [Field: introduction, subscore: 1.00]
SECTION: references. The C . elegans pharynx : a model for organogenesis 26 All WormBook content , except where otherwise noted , is licensed under a Commons Attribution License . [Field: references, subscore: 1.00]
SECTION: references. The Caenorhabditis elegans peb-1 gene encodes a novel DNA-binding protein involved in morphogenesis of the pharynx , vulva , and hindgut . [Field: references, subscore: 1.00]
SECTION: references. The GAR-3 muscarinic receptor cooperates with calcium signals to regulate muscle contraction in the Caenorhabditis elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. Article The C . elegans pharynx : a model for organogenesis 25 UBC-18 to regulate Abstract [Field: references, subscore: 1.00]
SECTION: references. CCA-1 , EGL-19 and Caenorhabditis elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. AST-1 , a novel ETS-box transcription factor , controls axon guidance and pharynx development in C . elegans . [Field: references, subscore: 1.00]
SECTION: references. Electrical activity and behavior in the pharynx of Caenorhabditis elegans . [Field: references, subscore: 1.00]
SECTION: references. Article The C . elegans pharynx : a model for organogenesis pha-2 encodes the C . elegans ortholog of the Abstract [Field: references, subscore: 1.00]
SECTION: references. Early morphogenesis of the Caenorhabditis elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. The C . elegans pharynx : a model for organogenesis 23 Abstract [Field: references, subscore: 1.00]
SECTION: references. , and Avery , L . ( 2004 ) . nicotinic neurotransmission in the Caenorhabditis elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. Article The C . elegans pharynx : a model for organogenesis 22 pha-4 Abstract [Field: references, subscore: 1.00]
SECTION: references. D . ( 1998 ) . is Ce-fkh-1 , a fork head / HNF-3alpha , beta , gamma homolog that functions in organogenesis of the C . elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. Interference between the PHA-4 and PEB-1 transcription factors in formation of the Caenorhabditis elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. Article The C . elegans pharynx : a model for organogenesis 21 Abstract [Field: references, subscore: 1.00]
SECTION: references. Article The C . elegans pharynx : a model for organogenesis 20 Abstract [Field: references, subscore: 1.00]
SECTION: references. Article The C . elegans pharynx : a model for organogenesis 19 Abstract [Field: references, subscore: 1.00]
SECTION: references. A fork head / HNF-3 homolog expressed in the pharynx and intestine of the Caenorhabditis elegans embryo . [Field: references, subscore: 1.00]
SECTION: references. Article The C . elegans pharynx : a model for organogenesis 18 Horner et al . , 1998 ; Kiefer et al . , 2006 ) . [Field: references, subscore: 1.00]
SECTION: references. The Caenorhabditis elegans ems class homeobox gene required for M3 pharynx motorneuron function . [Field: references, subscore: 1.00]
SECTION: references. The pharynx of Caenorhabditis elegans . [Field: references, subscore: 1.00]
SECTION: references. Many thanks to Alex Schier for comments on the manuscript , Leon Avery for discussions regarding pharynx neurobiology and evolution , David Hall and Zeynep Altun for for the Aph panel in Figure 8 and all my lab , current and past , for discussions on pharyngeal development . [Field: references, subscore: 1.00]
SECTION: references. To form the pharynx , C . elegans faces developmental challenges that are similar to those of more complex animals and uses conserved molecular pathways to meet those challenges . [Field: references, subscore: 1.00]
SECTION: references. The pharynx is excited by motor neurons via nicotinic receptors , similar to mammalian skeletal muscle ( McKay et al . , 2004 ; Raizen et al . , 1995 ; Towers et al . , 2005 action potential are only distantly related between pharyngeal and Avery , 2005 ) . [Field: references, subscore: 1.00]
SECTION: references. Third , aspects of the electrical conductivity are different between the pharynx and heart . [Field: references, subscore: 1.00]
SECTION: references. Contraction speed can be modulated by Hobson et al . , 2003 ; Penela et al . , Avery and Horvitz , 1989 ; Raizen and Avery , 1994 ; ceh-22 for the pharynx ; Okkema and Fire , 1994 ; Okkema et al . , 1997 ) . when expressed in C . elegans body wall muscles , and ceh-22 promoter ( Haun et al . , 1998 ) . [Field: references, subscore: 1.00]
SECTION: references. Located AJM-1 ( Bossinger cdh-3 is expressed in the pharynx and would be - or -integrins do not give rise to obvious ; Costa et al . , 1998 ; Drubin and Nelson , 1996 ; ; Harris and Peifer , 2004 ) . [Field: references, subscore: 1.00]
SECTION: references. In pha-4 mutant embryos , at least a portion of pharyngeal cells are The C . elegans pharynx : a model for organogenesis 17 Knust and ; Legouis et al . , 2000 ; McMahon et al . , Leung et al . , 1999 ) . [Field: references, subscore: 1.00]
SECTION: references. Third , both organs rely on NKX transcription factors for their genesis : and Nkx2 . 5 for the zebrafish heart ( Chen and Fishman , 1996 Moreover , Nkx2 . 5 can activate the CEH-22 target gene myo-2 Nkx2 . 5 can rescue ceh-22 mutants when expressed under control of the Despite these similarities , three observations suggest that parallels between the pharynx and heart may represent convergent evolution rather than true homology . [Field: references, subscore: 1.00]
SECTION: references. The pharynx and heart rely on some similar types of channels such as the LQT potassium channels and L-type voltage-gated calcium channels ( Salkoff et al . , 2005 ) . [Field: references, subscore: 1.00]
SECTION: references. First , both the pharynx and heart are tubes that move material along their lumens using binucleate muscles ( Thomson , 1976 ; Kellerman et al . , 1992 ) . [Field: references, subscore: 1.00]
SECTION: references. Three observations suggest that the pharynx may be orthologous to the vertebrate heart . [Field: references, subscore: 1.00]
SECTION: references. There has been debate about a possible evolutionary relationship between the C . elegans pharynx and the vertebrate heart . [Field: references, subscore: 1.00]
SECTION: references. Is the pharynx a heart ? [Field: references, subscore: 1.00]
SECTION: references. LET-413 , which contains a PDZ motif and leucine-rich repeats similar to Drosophila scribble , is localized to basolateral membranes of all epithelial cell types , including the pharynx ( In epidermal cells lacking let-413 / scribble , apical proteins such as proteins such as DLG-1 and AJM-1 remain along the lateral surface rather than becoming condensed into the junctional region as in wildtype ( McMahon et al . , 2001 ) . [Field: references, subscore: 1.00]
SECTION: references. What factors are required to build the pharynx epithelium ? [Field: references, subscore: 1.00]
SECTION: references. Similarly , inactivation of pha-1 an unattached pharynx phenotype ( Fay et al . , 2004 ; Qiu and Fay , 2006 interactions is that over-expression of a factor " X " leads to a Pun phenotype . [Field: references, subscore: 1.00]
SECTION: references. Some of these defects may reflect the lack of body elongation rather than internal to the pharynx itself . [Field: references, subscore: 1.00]
SECTION: references. DIE-1 analysis , including genes many genes implicated in transcription ( Deplancke et al . , 2006 sma-1 encodes H ( heavy ) -spectrin , which is essential for the elongated form of the pharynx ( 1998 ) . [Field: references, subscore: 1.00]
SECTION: references. die-1 mutants can be detached from either the intestine or from the buccal cavity ( expressed in the pharynx , although the precise cells are unknown . [Field: references, subscore: 1.00]
SECTION: references. die-1 encodes a zinc finger transcription factor expressed in many epithelia including the pharynx ( 2001 ) . [Field: references, subscore: 1.00]
SECTION: references. In worms , eya-1 mutants arrest at the L1 or L2 stage with a thin pharynx and reduced pumping rates ( Furuya et al . , 2005 ) . [Field: references, subscore: 1.00]
SECTION: references. In Pha animals , no pharynx is observed ( arrows ) . [Field: references, subscore: 1.00]
SECTION: references. Pha attachment Qiu and Fay , 2006 Nuclear Pha attachment Fay et al . , 2003 Apical Pha elongation McKeown et al . , 1998 Apical Pha elongation Norman and Moerman , 2002 ast-1 leads to pharynx ) . [Field: references, subscore: 1.00]
SECTION: references. The C . elegans pharynx : a model for organogenesis Localization Function References [Field: references, subscore: 1.00]
SECTION: references. It is unclear whether the pharyngeal defects reflect a function for AST-1 in the pharynx or in surrounding head cells . [Field: references, subscore: 1.00]
SECTION: references. Broadly sma-1 H-spectrin Z Epithelia spc-1 -spectrin Z Epithelia Many factors affect pharynx morphogenesis , based on loss-of-function phenotypes , but it is unclear if these phenotypes reflect cell fate , differentiation or morphogenesis . [Field: references, subscore: 1.00]
SECTION: references. The C . elegans pharynx : a model for organogenesis 14 Table 3 . [Field: references, subscore: 1.00]
SECTION: references. The basement membrane surrounding the pharynx is denoted by a dotted yellow line in both sets of panels . [Field: references, subscore: 1.00]
SECTION: references. During the third stage of pharyngeal extension , cells of the pharynx , buccal cavity and epidermis appear to undergo a local contraction that pulls them tightly together ( see Figure 7C to D ) . [Field: references, subscore: 1.00]
SECTION: references. This rearrangement alters the morphology of the pharynx from a cyst , with the apical surfaces located internally , to a short tube that extends from the midgut to the anterior edge of the pharyngeal primordium . [Field: references, subscore: 1.00]
SECTION: references. For example , when expressed ectopically , PHA-4 can change the fate of only a subset of embryonic cells to pharynx ( Horner et al . , 1998 ) . [Field: references, subscore: 1.00]
SECTION: references. Pharynx development depends on multiple stages of development and in all pharyngeal cell types . [Field: references, subscore: 1.00]
SECTION: references. Transcriptional strategies for organogenesis It is intriguing to compare the transcriptional strategies of cell fate specification and differentiation for the pharynx vs . the midgut , two very different organs . [Field: references, subscore: 1.00]
SECTION: references. One was necessity : were the sequences required for expression of natural The C . elegans pharynx : a model for organogenesis 11 Use References [Field: references, subscore: 1.00]
SECTION: references. Combinatorial regulation is the third means to control timing ( see similar to what exists in most promoters , is not sufficient to activate expression ( PHA-4 binding sites can activate transcription throughout the pharynx , but this configuration is rarely seen in natural promoters ( Gaudet et al . , 2004 ) . [Field: references, subscore: 1.00]
SECTION: references. Promoter analyses suggest that genes expressed in the pharynx , including genes active both early and late , ( 2004 ; Kalb et al . , 1998 ; Kuchenthal et al . , 2001 ; Smith and Mango , 2006 PHA-4 for its binding sites contributes to the timing of target gene activation ( al . , 2004 ) . [Field: references, subscore: 1.00]
SECTION: references. Name URL BioProspector http : / / ai . stanford . edu / xsliu / BioProspector / BioTapestry http : / / labs . systemsbiology . net / bolouri / software / BioTapestry / CisOrtho http : / / dev . wormbase . org / CisOrtho / ClusterBuster http : / / cagt . bu . edu / page / ClusterBuster_about Co-Bind http : / / ural . wustl . edu / software . html Compare Prospector http : / / ai . stanford . edu / iliu / CompareProspector / index . html ConSite http : / www . phylofoot . org / consite Cytoscape http : / / www . cytoscape . org / GSEA http : / / www . broad . mit . edu / gsea / Improbizer http : / / www . cse . ucsc . edu / kent / improbizer / improbizer . html JASPAR http : / / jaspar . genereg . net MEME / MAST http : / / meme . sdsc . edu / meme / intro . html The C . elegans pharynx : a model for organogenesis Shimono et al . , 2003 ) . [Field: references, subscore: 1.00]
SECTION: references. Repression of ectodermal fate also requires the NuRD complex and the TRIM factor which associates with PHA-4 in yeast two-hybrid assays ( Kiefer et al . , 2006 The C . elegans pharynx : a model for organogenesis 9 ) . [Field: references, subscore: 1.00]
SECTION: references. However , it is likely that additional , undiscovered regulators exist . The C . elegans pharynx : a model for organogenesis 8 MS fate into that of C , leading to loss of ; Maduro et al . , 2001 ) . [Field: references, subscore: 1.00]
SECTION: references. In the pharynx , the timing of activation suggests that regulated directly by LAG-1 and TBX-37 / 38 within ABa descendents at the 24-cell stage ( TBX-35 in the MS lineage ( Broitman-Maduro et al . , 2006 ) . [Field: references, subscore: 1.00]
SECTION: references. Thus , pha-4 behaves as an organ selector gene ( that specifies pharynx identity for both ABa and MS-derived blastomeres . [Field: references, subscore: 1.00]
SECTION: references. The organ selector gene pha-4 The central regulator of pharynx development is pha-4 , a FoxA transcription factor ( et al . , 1998 ; Mango et al . , 1994 ) . [Field: references, subscore: 1.00]
SECTION: references. The lineage restriction seen at this time applies to pharyngeal fate generally , not to individual cell types found within the pharynx . [Field: references, subscore: 1.00]
SECTION: references. By contrast , later in development , cells that are destined to make the pharynx and that derive from different cell lineages , coordinate their development to form an integrated , functioning structure . [Field: references, subscore: 1.00]
SECTION: references. Loss of both med genes leads to conversion of the posterior pharynx ( Goszczynski and McGhee , 2005 ; Maduro et al . , 2006 currently debate regarding the contribution of the MED factors , with one report suggesting few embryos have an MS to C fate transformation ( Goszczynski and McGhee , 2005 ) and other studies suggesting a greater proportion of embryos are affected ( Maduro et al . , 2006 ; Maduro et al . , 2001 ) . [Field: references, subscore: 1.00]
SECTION: references. skn-1 encodes an EMS blastomere ( Bowerman et al . , skn-1 , no pharynx is produced because EMS descendents are C does not generate Notch ligands to signal to ABa . [Field: references, subscore: 1.00]
SECTION: references. The role of ( Broitman-Maduro et al . , 2005 ; Calvo et al . , 2001 The MS and E blastomeres also express the GATA-like factors gene products are contributed maternally ( Maduro et al . , 2006 The C . elegans pharynx : a model for organogenesis tbx-35 , tbx-37 , tbx-38 and pha-4 . [Field: references, subscore: 1.00]
SECTION: references. In the absence of transformed into their cousin , the C blastomere , and encodes a Tcf / Lef-1 homolog that is enriched in the nucleus of a daughter of wingless signalling pathway and lit-1 kinase ( Lin et al . , 1995 develops like E and MS -derived pharyngeal cells are lost ( and so the anterior pharynx is still made . [Field: references, subscore: 1.00]
SECTION: references. The pharynx is generated from green blastomeres ( Descendents of green cells that do not produce pharyngeal cells are grey . [Field: references, subscore: 1.00]
SECTION: title. The C . elegans pharynx : a model for organogenesis . [Field: title, subscore: 1.00]
Supplemental links/files: reference in endnote reference in xml Wormbase reference
Score: 126.00
Title: Cell architecture : surrounding muscle cells shape gland cell morphology in the Caenorhabditis elegans pharynx .
Authors: Raharjo WH ; Ghai V ; Dineen A ; Bastiani M ; Gaudet J
Journal: Genetics
Year: 2011-11-25
Doc ID: WBPaper00040002
Bibliographic Information
Abstract
Matching Sentences
SECTION: introduction. In sma-1 mutants , gland functions in the surrounding musculature , suggesting that pharynx , as does the relative simplicity pharynx also exhibits features of more and the presence of multiple different cell pharynx to the buccal ( or mouth ) and the intricate formation of two toroid pm8 and vpi1 ) that connect the pharynx to the in- ( Portereiko and Mango 2001 ; Rasmussen et al . pharynx pharynx to Pun ) mutants , the organ generally pharyngeal cells ( Fay et al . 2004 ; Qiu and Fay pm8 and pharynx is likewise Genetics , Vol . 189 , 885897 November 2011 885 a study of cell shape arising from a combination of intrinsic cellular properties and interactions with neighboring cells . [Field: introduction, subscore: 7.00]
SECTION: non-sectioned. Note that the longest projection , from g1A , has defects in the posterior ( right ) half of the pharynx while the anterior portion of the projection looks normal . ( B ) Gland defects in pha-2 mutants are largely restricted to the posterior pharynx ; shown is percent mutants with moderate to severe defects in the anterior or posterior halves of the g1P projection ( g1P-ant and g1P-post , respectively ) and for the g1A gland projections , which reside in the posterior half of the pharynx ( n = 52 ) . [Field: body, subscore: 3.00]
SECTION: results. Note that the longest projection , from g1A , has defects in the posterior ( right ) half of the pharynx while the anterior portion of the projection looks normal . ( B ) Gland defects in pha-2 mutants are largely restricted to the posterior pharynx ; shown is percentage of mutants with moderate-to-severe defects in the anterior or posterior halves of the g1P projection ( g1P-ant and g1P-post , respectively ) and for the g1A gland projections , which reside in the posterior half of the pharynx ( n 52 ) . [Field: results, subscore: 3.00]
SECTION: non-sectioned. In most cases , the dorsal gland ( comparable to g1P ) extends to near the end of the pharynx , while the subventral glands ( comparable to g1A ) extend roughly halfway along the length of the pharynx , though there are some exceptions with respect to both cell body position and length of projections . [Field: body, subscore: 2.00]
SECTION: non-sectioned. Interestingly , the pharyngeal glands ( also called esophageal glands ) of other nematodes generally resemble those of C . elegans , with cell bodies in the posterior of the pharynx and long cellular extensions that reach to discrete points along the length of the pharynx ( CHITWOOD and CHITWOOD 1950 ) . [Field: body, subscore: 2.00]
SECTION: non-sectioned. For example , growth of the pharynx may place tension on the gland projection to stimulate growth ; loss of this attachment by severing could result in a failure of the gland projection to grow or even in a retraction of the projection during subsequent growth of the pharynx . [Field: body, subscore: 2.00]
SECTION: non-sectioned. In the case of pharyngeal attachment , changes in cell shape and orientation at the anterior end of the pharynx lead to epithelial connections that anchor the pharynx to the mouth of the animal ; this connection is ultimately required for the proper elongation of the organ as a whole . [Field: body, subscore: 2.00]
SECTION: non-sectioned. Previous studies have elucidated some aspects of pharyngeal morphogenesis , such as the attachment of the pharynx to the buccal cavity ( or mouth ) , and the intricate formation of two toroid cells ( pm8 and vpi1 ) that connect the pharynx to the intestine ( PORTEREIKO and MANGO 2001 ; RASMUSSEN et al . 2008 ) . [Field: body, subscore: 2.00]
SECTION: discussion. In most cases , the dorsal gland ( comparable to g1P ) extends to near the end of the pharynx , while the subventral glands ( comparable to g1A ) extend roughly halfway along the length of the pharynx , though there are some exceptions with respect to both cell body position and length of projections . [Field: discussion, subscore: 2.00]
SECTION: discussion. Interestingly , the pharyngeal glands ( also called esophageal glands ) of other nematodes generally resemble those of C . elegans , with cell bodies in the posterior of the pharynx and long cellular extensions that reach to discrete points along the length of the pharynx ( Chitwood and Chitwood 1950 ) . [Field: discussion, subscore: 2.00]
SECTION: results. For example , growth of the pharynx may place tension on the gland projection to stimulate growth ; loss of this attachment by severing could result in a failure of the gland projection to grow or even in a retraction of the projection during subsequent growth of the pharynx . [Field: results, subscore: 2.00]
SECTION: abstract. The most severe such mutant is an allele of sma-1 , which encodes a -spectrin required for embryonic elongation , including elongation of the pharynx . [Field: abstract, subscore: 1.00]
SECTION: non-sectioned. , and S . E . MANGO , 2001 Early morphogenesis of the Caenorhabditis elegans pharynx . [Field: body, subscore: 1.00]
SECTION: non-sectioned. , C . AXANG and M . PILON , 2003 A genetic analysis of axon guidance in the C elegans pharynx . [Field: body, subscore: 1.00]
SECTION: non-sectioned. , G . RUVKUN and T . R . BURGLIN , 2003 The Caenorhabditis elegans ems class homeobox gene ceh-2 is required for M3 pharynx motoneuron function . [Field: body, subscore: 1.00]
SECTION: non-sectioned. , and J . N . THOMSON , 1976 The pharynx of Caenorhabditis elegans . [Field: body, subscore: 1.00]
SECTION: non-sectioned. In all three sma mutants , mean pharynx length is significantly smaller than that of N2 ( p < 0 . 001 , Students t-test ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. Mean pharynx length in adult animals ( standard deviation ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. ( A ) Gland projections in the posterior pharynx are severely misshapen in pha-2 mutants . [Field: body, subscore: 1.00]
SECTION: non-sectioned. All images are of phat-1 : : YFP expression and the dashed line outlines the pharynx . [Field: body, subscore: 1.00]
SECTION: non-sectioned. ( F ) sma-1 ( iv38 ) mutants exhibit severe swelling and occasional branching of gland projections , and the pharynx is incompletely elongated . [Field: body, subscore: 1.00]
SECTION: non-sectioned. ( E ) Abnormal swelling of gland projections in the anterior pharynx of iv50 homozygote ( arrowheads ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. In all images , the white dashed line indicates the outline of pharynx , and anterior is at left . [Field: body, subscore: 1.00]
SECTION: non-sectioned. ( B ) Cross-section through the isthmus of the pharynx ( as indicated by the dashed lines in A ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. At the top is the g1P gland , which has the longest gland projection , connecting to the pharyngeal lumen ( thick black line ) near the anterior end of the pharynx . [Field: body, subscore: 1.00]
SECTION: non-sectioned. ( A ) The pharynx of C . elegans , emphasizing the five glands ( green cytoplasm , dark green nuclei ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. How do the gland projections scale during growth of the pharynx ? [Field: body, subscore: 1.00]
SECTION: non-sectioned. Interestingly , our genetic screen identified other mutants with localized defects in the pharyngeal gland projections , but apparently normal pharynx morphology . [Field: body, subscore: 1.00]
SECTION: non-sectioned. At least one function of the glands is to secrete mucin-like PHAT proteins that line the pharyngeal lumen , and these secretions may aid in the passage of food along the pharynx ( SMIT et al . 2008 ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. 22 DISCUSSION The long cellular projections of the pharyngeal glands extend to discrete points along the length of the pharynx , allowing the glands to secrete material into the pharyngeal lumen . [Field: body, subscore: 1.00]
SECTION: non-sectioned. This result suggests that muscle and gland growth are counterbalanced : where the gland projection remains intact , the gland is able to continue growing in scale with the rest of the pharynx ; where the gland projection has been eliminated as a result of severing , the pharyngeal muscles close in and prevent further invasion by the glands . [Field: body, subscore: 1.00]
SECTION: non-sectioned. Thus , the length of the gland projection would remain constant or would shrink following surgery , with the distance between the duct and point of surgery increasing as the pharynx grows . [Field: body, subscore: 1.00]
SECTION: non-sectioned. Normally , glands continue to grow throughout the life of the animal , keeping pace with growth of the pharynx and the rest of the body . [Field: body, subscore: 1.00]
SECTION: non-sectioned. Interestingly , the defects in the gland projections are largely confined to the posterior pharynx ( Figure 6B ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. In pha-2 mutants , the pharynx is incompletely elongated , exhibiting a shortened pharyngeal isthmus as a result of defects in the differentiation of the pm5 muscles ( AVERY 1993 ; MORCK et al . 2004 ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. 17 Removal of a pharynx muscle-specific troponin T ( tnt-4 ) results in gland defects like those seen in sma-1 ( and other ) mutants . [Field: body, subscore: 1.00]
SECTION: non-sectioned. Mutants have normal pharynx morphology , but gland projections are frequently defective , with 47 % of mutants exhibiting swelling of projections or outgrowths along their length ( Figure 5F ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. These mutants are expected to affect integrity of the musculature but not elongation of the pharynx , in contrast to sma-1 mutants . [Field: body, subscore: 1.00]
SECTION: non-sectioned. One aspect of the sma-1 mutant phenotype is incomplete elongation of both the embryo and the pharynx . [Field: body, subscore: 1.00]
SECTION: non-sectioned. However , based on our analyses of glands in other mutants ( below ) , we propose that glands in sma-1 mutants are defective because of defects in pharyngeal muscle integrity rather than the smaller size of the pharynx . [Field: body, subscore: 1.00]
SECTION: non-sectioned. Thus , one interpretation is that the gland defect in sma-1 mutants is not due to the smaller pharynx size , but rather due to defects in elongation and / or structure of the pharyngeal muscles . [Field: body, subscore: 1.00]
SECTION: non-sectioned. Although not previously reported , we find that the average pharynx length in sma-2 and sma-3 adult animals is significantly smaller than that of wild type animals of the same age ( Table 2 ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. We therefore examined other mutants with reduced pharynx size , namely sma-2 and sma-3 , which encode downstream signaling components of a TGF signaling pathway required for 15 normal C . elegans size ( SAVAGE et al . 1996 ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. One possible explanation for the gland defects in sma-1 mutants is that the glands are growing to normal size / volume while contained in a smaller pharynx . [Field: body, subscore: 1.00]
SECTION: non-sectioned. Defects in pharyngeal muscles result in abnormal gland morphology To test the general hypothesis that the pharyngeal muscles are important in maintenance of gland morphology , we examined glands in two classes of mutants : those in which pharynx size was reduced but in which pharyngeal muscles were otherwise normal , and those in which pharyngeal elongation and / or muscle structure were impaired . [Field: body, subscore: 1.00]
SECTION: non-sectioned. In iv50 mutants , defects are not restricted to the anterior bulb region , but are instead visible along the anterior half of the pharynx in 71 % ( n = 66 ) of animals . [Field: body, subscore: 1.00]
SECTION: non-sectioned. In iv37 homozygotes , defects are restricted to the anterior bulb region of the pharynx , with 57 % ( n = 61 ) of animals showing defects in the g1P and / or the g1A cells . [Field: body, subscore: 1.00]
SECTION: non-sectioned. Genetic screening identifies a variety of gland defects Gland projections are proposed to develop during embryogenesis , as gland cells migrate from their site of birth to their final position in the pharynx ( SULSTON et al . 1983 ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. Post-embryonically , the gland projections grow roughly 2-fold , in conjunction with growth of the pharynx . [Field: body, subscore: 1.00]
SECTION: non-sectioned. The longest projection is made by g1P and extends a distance of 125 m in adults , terminating at a duct near the anterior end of the pharynx . [Field: body, subscore: 1.00]
SECTION: non-sectioned. The five pharyngeal glands are single-celled structures , whose cell bodies reside in the posterior bulb of the pharynx ( Figure 1A ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. Other cells within the pharynx have unique and interesting morphologies , such as the pharyngeal glands ( ALBERTSON and THOMSON 1976 ) , which are the focus of this paper . [Field: body, subscore: 1.00]
SECTION: non-sectioned. The formation of the pm8 and vpi1 cells at the posterior end of the pharynx is likewise a study of cell shape arising from a combination of intrinsic cellular properties and interactions with neighboring cells . [Field: body, subscore: 1.00]
SECTION: non-sectioned. In pharynx unattached ( Pun ) mutants , the organ generally lacks the distinct bilobed shape that results from differential elongation of pharyngeal cells ( FAY et al . 2004 ; MANI and FAY 2009 ; QIU and FAY 2006 ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. However , the pharynx also exhibits features of more complex organs , in particular the diverse lineal histories of pharyngeal cells and the presence of multiple different cell types within the organ ( SULSTON et al . 1983 ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. The usual advantages of model organism genetics and the transparency of the nematode apply to study of the pharynx , as does the relative simplicity of the organ ( 95 cells in total ) ( KORMISH et al . 2010 ; MANGO 2009 ) . [Field: body, subscore: 1.00]
SECTION: non-sectioned. The C . elegans pharynx serves as a useful model for organ development : morphogenetic events can be analyzed both at the level of the whole organ and at the level of individual cells . [Field: body, subscore: 1.00]
SECTION: non-sectioned. The most severe such mutant is an allele of sma-1 , which encodes a -spectrin required for embryonic elongation , including elongation of the pharynx . [Field: body, subscore: 1.00]
SECTION: non-sectioned. Running title : Keywords : Corresponding Author : Gland morphology in C . elegans gland , pharynx , C . elegans , sma-1 , morphogenesis , spectrin Jeb Gaudet Dept . of Biochemistry and Molecular Biology 3330 Hospital Drive NW Calgary , Alberta , T2N 4N1 , Canada ( P ) : 403-210-8713 gaudetj @ ucalgary . ca 2 ABSTRACT [Field: body, subscore: 1.00]
SECTION: non-sectioned. 111 . 132449 00040002 Cell architecture : surrounding muscle cells shape gland cell morphology in the C . elegans pharynx by Wahyu Hendrati Raharjo , Vikas Ghai1 , 2 , Aidan Dineen1 , 3 , Michael Bastiani4 and Jeb Gaudet1 , 2 1 1 Genes and Development Research Group , for Child and Maternal Health , Alberta Children ' s Hospital Research Institute 2 3 Department of Molecular Biology and Biochemistry University of Calgary , Calgary , Alberta CANADA 4 Graduate Program in Medical and Molecular Genetics Department of Biology USA University of Utah , Salt Lake City , Utah 1 Copyright 2011 . [Field: body, subscore: 1.00]
SECTION: discussion. How do the gland projections scale during growth of the pharynx ? [Field: discussion, subscore: 1.00]
SECTION: discussion. Interestingly , our genetic screen identified other mutants with localized defects in the pharyngeal gland projections , but apparently normal pharynx morphology . [Field: discussion, subscore: 1.00]
SECTION: discussion. At least one function of the glands is to secrete mucin-like PHAT proteins that line the pharyngeal lumen , and these secretions may aid in the passage of food along the pharynx ( Smit et al . 2008 ) . [Field: discussion, subscore: 1.00]
SECTION: discussion. Discussion The long cellular projections of the pharyngeal glands extend to discrete points along the length of the pharynx , allowing the glands to secrete material into the pharyngeal lumen . [Field: discussion, subscore: 1.00]
SECTION: introduction. Postembryonically , the gland projections grow roughly twofold , in conjunction with growth of the pharynx . [Field: introduction, subscore: 1.00]
SECTION: introduction. The longest projection is made by g1P and extends a distance of 125 mm in adults , terminating at a duct near the anterior end of the pharynx . [Field: introduction, subscore: 1.00]
SECTION: introduction. The five pharyngeal glands are single-celled structures , whose cell bodies reside in the posterior bulb of the pharynx ( Figure 1A ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. Other cells within the pharynx have unique and interesting morphologies , such as the pharyngeal glands ( Albertson and Thomson 1976 ) , which are the focus of this article . [Field: introduction, subscore: 1.00]
SECTION: introduction. From a genetic sma-1 , pharynx . [Field: introduction, subscore: 1.00]
SECTION: introduction. In pharynx unattached ( lacks the distinct bilobed shape that results from differential elongation of 2006 ; Mani and Fay 2009 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. The Caenorhabditis elegans pharynx serves as a useful model for organ development : morphogenetic events can be analyzed both at the level of the whole organ and at the level of individual cells . [Field: introduction, subscore: 1.00]
SECTION: introduction. Cell Architecture : Surrounding Muscle Cells Shape Gland Cell Morphology in the Caenorhabditis elegans Pharynx Wahyu Hendrati Raharjo , * Vikas Ghai , * , Aidan Dineen * Genes and Development Research Group , Alberta Children ' s Hospital Research Institute for Child and Maternal Health , Department of Molecular Biology and Biochemistry , and Graduate Program in Medical and Molecular Genetics , University of Calgary , Calgary , Alberta , T2N 4N1 , Canada , and Department of Biology , University of Utah , Salt Lake City , Utah 84112 ABSTRACT [Field: introduction, subscore: 1.00]
SECTION: materials. ( B ) Cross-section through the isthmus of the pharynx ( as indicated by the dashed lines in A ) . [Field: materials, subscore: 1.00]
SECTION: materials. At the top is the g1P gland , which has the longest gland projection , connecting to the pharyngeal lumen ( thick black line ) near the anterior end of the pharynx . [Field: materials, subscore: 1.00]
SECTION: materials. ( A ) The pharynx of C . elegans , emphasizing the five glands ( green cytoplasm , dark green nuclei ) . [Field: materials, subscore: 1.00]
SECTION: references. DC1 Cell Architecture : Surrounding Muscle Cells Shape Gland Cell Morphology in the Caenorhabditis elegans Pharynx Wahyu Hendrati Raharjo , Vikas Ghai , Aidan Dineen , Michael Bastiani , and Jeb Gaudet Copyright 2011 by the Genetics Society of America DOI : 10 . 1534 / genetics . [Field: references, subscore: 1.00]
SECTION: references. , and S . E . Mango , 2001 Early morphogenesis of the Caenorhabditis elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. , C . Axang , and M . Pilon , 2003 A genetic analysis of axon guidance in the C . elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. , G . Ruvkun , and T . R . Burglin , 2003 The Caenorhabditis elegans ems class homeobox gene ceh-2 is required for M3 pharynx motoneuron function . [Field: references, subscore: 1.00]
SECTION: references. , and J . N . Thomson , 1976 The pharynx of Caenorhabditis elegans . [Field: references, subscore: 1.00]
SECTION: results. This result suggests that muscle and gland growth are counterbalanced : where the gland projection remains intact , the gland is able to continue growing in scale with the rest of the pharynx ; where the gland projection has been eliminated as a result of severing , the pharyngeal muscles " close in " and prevent further invasion by the glands . [Field: results, subscore: 1.00]
SECTION: results. Thus , the length of the gland projection would remain constant or would shrink following surgery , with the distance between the duct and point of surgery increasing as the pharynx grows . [Field: results, subscore: 1.00]
SECTION: results. Normally , glands continue to grow throughout the life of the animal , keeping pace with growth of the pharynx and the rest of the body . [Field: results, subscore: 1.00]
SECTION: results. ( A ) Gland projections in the posterior pharynx are severely misshapen in pha-2 mutants . [Field: results, subscore: 1.00]
SECTION: results. Interestingly , the defects in the gland projections are largely confined to the posterior pharynx ( Figure 6B ) . [Field: results, subscore: 1.00]
SECTION: results. In pha-2 mutants , the pharynx is incompletely elongated , exhibiting a shortened pharyngeal isthmus as a result of defects in the differentiation of the pm5 muscles ( Avery 1993 ; Morck et al . 2004 ) . [Field: results, subscore: 1.00]
SECTION: results. Removal of a pharynx muscle-specific troponin T ( tnt-4 ) results in gland defects like those seen in sma-1 ( and other ) mutants . [Field: results, subscore: 1.00]
SECTION: results. Mutants have normal pharynx morphology , but gland projections are frequently defective , with 47 % of mutants exhibiting swelling of projections or outgrowths along their length ( Figure 5F ) . [Field: results, subscore: 1.00]
SECTION: results. These mutants are expected to affect integrity of the musculature but not elongation of the pharynx , in contrast to sma-1 mutants . [Field: results, subscore: 1.00]
SECTION: results. All images are of phat-1 : : YFP expression and the dashed line outlines the pharynx . [Field: results, subscore: 1.00]
SECTION: results. One aspect of the sma-1 mutant phenotype is incomplete elongation of both the embryo and the pharynx . [Field: results, subscore: 1.00]
SECTION: results. However , on the basis of our analyses of glands in other mutants ( below ) , we propose that glands in sma-1 mutants are defective because of defects in pharyngeal muscle integrity rather than the smaller size of the pharynx . [Field: results, subscore: 1.00]
SECTION: results. Thus , one interpretation is that the gland defect in sma-1 mutants is not due to the smaller pharynx size , but rather due to defects in elongation and / or structure of the pharyngeal muscles . [Field: results, subscore: 1.00]
SECTION: results. Although not previously reported , we find that the average pharynx length in sma-2 and sma-3 adult animals is significantly smaller than that of wild-type animals of the same age ( Table 2 ) . [Field: results, subscore: 1.00]
SECTION: results. We therefore examined other mutants with reduced pharynx size , namely sma-2 and sma-3 , which encode downstream signaling components of a TGFb signaling pathway required for normal C . elegans size ( Savage et al . 1996 ) . [Field: results, subscore: 1.00]
SECTION: results. One possible explanation for the gland defects in sma-1 mutants is that the glands are growing to normal size / volume while contained in a smaller pharynx . [Field: results, subscore: 1.00]
SECTION: results. Defects in pharyngeal muscles result in abnormal gland morphology To test the general hypothesis that the pharyngeal muscles are important in maintenance of gland morphology , we examined glands in two classes of mutants : those in which pharynx size was reduced but in which pharyngeal muscles were otherwise normal and those in which pharyngeal elongation and / or muscle structure were impaired . [Field: results, subscore: 1.00]
SECTION: results. In iv50 mutants , defects are not restricted to the anterior bulb region , but are instead visible along the anterior half of the pharynx in 71 % ( n = 66 ) of animals . [Field: results, subscore: 1.00]
SECTION: results. In iv37 homozygotes , defects are restricted to the anterior bulb region of the pharynx , with 57 % ( n = 61 ) of animals showing defects in the g1P and / or the g1A cells . [Field: results, subscore: 1.00]
SECTION: results. ( F ) sma-1 ( iv38 ) mutants exhibit severe swelling and occasional branching of gland projections , and the pharynx is incompletely elongated . [Field: results, subscore: 1.00]
SECTION: results. ( E ) Abnormal swelling of gland projections in the anterior pharynx of iv50 homozygote ( arrowheads ) . [Field: results, subscore: 1.00]
SECTION: results. In all images , the open dashed line indicates the outline of pharynx , and anterior is at left . [Field: results, subscore: 1.00]
SECTION: results. Genetic screening identifies a variety of gland defects Gland projections are proposed to develop during embryogenesis , as gland cells migrate from their site of birth to their final position in the pharynx ( Sulston et al . 1983 ) . [Field: results, subscore: 1.00]
SECTION: title. Cell architecture : surrounding muscle cells shape gland cell morphology in the Caenorhabditis elegans pharynx . [Field: title, subscore: 1.00]
Match: [Sentence(s) appears to be scrambled. Click to see (opens new window)] [Field: results, subscore: 3.00]
Match: [Sentence(s) appears to be scrambled. Click to see (opens new window)] [Field: body, subscore: 1.00]
Supplemental links/files: reference in endnote reference in xml Wormbase reference
Score: 112.00
Title: The twisted pharynx phenotype in C . elegans .
Authors: Axang C ; Rauthan M ; Hall DH ; Pilon M
Journal: BMC Dev Biol
Year: 2007
Doc ID: WBPaper00030736
Bibliographic Information
Abstract
Matching Sentences
SECTION: conclusion. The twisted pharynx phenotype is not a result of pumping activity nor the consequence of an external twisting force applied to the pharynx : it results from a twisting force intrinsic to the pharynx . [Field: conclusion, subscore: 3.00]
SECTION: discussion. This result also suggests that the pharyngeal cuticle is not directly restraining an intrinsic twist . We also found that the attachmentof the pharynx to the bodywall at the lips is not preventing the pharynx from twisting in L1 larvae ( Fig . 8 ) , and that the pharyngeal tendons that connect the procorpus to the bodywall appear intact , albeit spirally oriented , in animals with a twisted pharynx ( Fig . 4 ) . [Field: discussion, subscore: 3.00]
SECTION: introduction. The pharynx is sometimes considered to be evolutionarily related to the heart because : ( i ) like the heart , the pharynx is a rhythmically contracting muscular pump [ 3 ] ; ( ii ) the muscle cells of the pharynx have autonomous contractile activity reminiscent of cardiac myocytes [ 4 ] ; and ( iii ) ceh-22 , the C . elegans homolog to the homeobox gene Nk2x . [Field: introduction, subscore: 3.00]
SECTION: discussion. Anterior detachment of the pharynx does not result in increased or earlier pharyngeal twisting Figure 8 Anterior detachment of the pharynx does not result in increased or earlier pharyngeal twisting . [Field: discussion, subscore: 2.00]
SECTION: results. Neither of these phenotypes was associated with pharyngeal twist- The anterior part of the intestine is twisted in a direction opposite to that of the pharynx Figure 6 The anterior part of the intestine is twisted in a direction opposite to that of the pharynx . [Field: results, subscore: 2.00]
SECTION: results. ( F ) and ( H ) : geometry of the tendons ( brown ) and pharynx ( blue circle ) viewed in cross sections if the pharynx is not twisted ( F ) or if it were twisted as a whole while held by the tendons ( H ) . [Field: results, subscore: 2.00]
SECTION: results. Of particular importance is that the pharynx seems to float in pseudocoelomic fluid and to make almost no contact with the worm body along its entire length : except for the tendons , the pharynx is secured only at its anterior and posterior ends , where it is connected to the mouth and intestine , respectively . [Field: results, subscore: 2.00]
SECTION: results. Anatomical features of the head region and comparison of the hemicentinrich pharyngeal tendons between wild-type and a mutant with the twisted pharynx phenotype Figure 4 Anatomical features of the head region and comparison of the hemicentin-rich pharyngeal tendons between wild-type and a mutant with the twisted pharynx phenotype . [Field: results, subscore: 2.00]
SECTION: results. BMC Developmental Biology 2007 , 7 : 61 http : / / www . biomedcentral . com / 1471-213X / 7 / 61 Page 6 of 13 ( page number not for citation purposes ) The anterior pharynx is firmly anchored to the lips by intercellular junctions , and more tenuously , via buccal cuticle Besides the tendon contacts along its anterior length , the pharynx is alsoconnected directly to the body-wall at its extreme anterior end , at the lips [ 1 ] . [Field: results, subscore: 2.00]
SECTION: results. him-4 mutants , with defective hemicentin and hence lacking these tendons [ 2 ] do not twist , indicating that lack of the support provided by the tendons is not enough to cause a twist . Also , these tendons do not seem to be involved in transferring a twisting force from outside the pharynx since mnm-4 ; him-4 double mutants still have a twisted pharynx ( data not shown ) . [Field: results, subscore: 2.00]
SECTION: results. BMC Developmental Biology 2007 , 7 : 61 http : / / www . biomedcentral . com / 1471-213X / 7 / 61 Page 5 of 13 ( page number not for citation purposes ) The pharyngeal tendons are pulled by the twisted pharynges The basal surface of the pharynx is covered by a thick basal lamina ( See Fig . 4AC ) , and four rows of 1520 acellular tendinous organs composed of hemicentin and fibulin that anchor the anterior end of the pharynx to the basal lamina that covers the bodywall muscles . [Field: results, subscore: 2.00]
SECTION: results. The twisted pharynx phenotype in mnm-4 ; etIs2 worms of different stages , and in adult mnm-4 ; unc-61 Figure 1 The twisted pharynx phenotype in mnm-4 ; etIs2 worms of different stages , and in adult mnm-4 ; unc-61 . [Field: results, subscore: 2.00]
SECTION: results. Note that the control pharynx of wild-type worms carrying the etIs2 integrated sequence is straight , and that the isolated pharynges of mnm-4 ; etIs2 , mnm-4 , mig-4 and unc-61 worms are twisted whereas the pharynx of the dig-1 animal is untwisted . [Field: results, subscore: 2.00]
SECTION: results. The twisted pharynx is fully functional Twisted pharynges performed as well as wild-type pharynges in bead uptake assays designed to measure feeding : there was a similar steady state number of beads within the pharynx ( i . . beads did not become stuck in twisted pharynges ) and a similar rate of transfer to the intestine ( Fig . 3 ) . [Field: results, subscore: 2.00]
SECTION: results. Quantitation of the twisted pharynx phenotype By measuring the torsion lines seen in a twisted pharynx , one can calculate the degree of twist ( Fig . 1A ) . [Field: results, subscore: 2.00]
SECTION: abstract. The twisted pharynx is a useful and easy-to-score phenotype for genes required in extracellular adhesion or organ attachment , and perhaps for genes required for cytoskeleton regulation . [Field: abstract, subscore: 1.00]
SECTION: abstract. In a mini screen of adhesion molecule mutants , we also identified one more twisting pharynx mutant , sax-7 . [Field: abstract, subscore: 1.00]
SECTION: abstract. : We find that the twisting phenotype worsens throughout larval development , that in most mutants the pharynx retains its twist when dissected away from the worm body , and that double mutants between mnm-4 and mutants with thickened pharyngeal domains ( pha-2 and sma-1 ) have less twisting in these regions . [Field: abstract, subscore: 1.00]
SECTION: abstract. Several C . elegans mutants have been reported to exhibit a twisted pharynx phenotype but no careful studies have been made to directly address this phenomenon . [Field: abstract, subscore: 1.00]
SECTION: abstract. : BACKGROUND : The pharynx of C . elegans is an epithelial tube whose development has been compared to that of the embryonic heart and the kidney and hence serves as an interesting model for organ development . [Field: abstract, subscore: 1.00]
SECTION: conclusion. The twisted pharynx phenotype is found in several C . elegans mutants that have defects in adhesion molecules or molecules that regulate attachment of the actin cytoskeleton to the cell cortex . 2 . [Field: conclusion, subscore: 1.00]
SECTION: discussion. The twisted pharynx is a useful and easy-to-score phenotype , allowing one to screen for new genes involved in extracellular adhesion or organ cohesion . [Field: discussion, subscore: 1.00]
SECTION: discussion. The unc-61 ; mnm-4 double mutant did not show any increase in twisting of the pharynx nor any additive effect on the gonad phenotype ( unpublished observations ) : it is possible that unc-61 and mnm-4 may function in the same pathway . [Field: discussion, subscore: 1.00]
SECTION: discussion. However , only unc-61 displays the twisted pharynx phenotype . [Field: discussion, subscore: 1.00]
SECTION: discussion. Septins are conserved GTP-binding proteins that polymerize to form filamentous structures that act as scaffolds for membrane- and cytoskeleton-binding proteins [ 31 ] , a function consistent with our hypothesis that defects in BMC Developmental Biology 2007 , 7 : 61 http : / / www . biomedcentral . com / 1471-213X / 7 / 61 Page 10 of 13 ( page number not for citation purposes ) cytoskeleton anchorage points is responsible for the twisted pharynx phenotype . [Field: discussion, subscore: 1.00]
SECTION: discussion. It is likely that its other morphological defects , such as the twisted pharynx , also are caused by impaired adhesion . [Field: discussion, subscore: 1.00]
SECTION: discussion. Importantly , all three molecules are expressed in the pharynx [ 9 , 26 , 27 ] . [Field: discussion, subscore: 1.00]
SECTION: discussion. Interference with normal regulation of actin filament length could produce the observed abnormally long filaments ( Fig . 5 ) and also explain a steadily increasing force that could be relieved by gradualtwisting of the whole pharynx to lengthen each sarcomere . [Field: discussion, subscore: 1.00]
SECTION: discussion. This action normally should not introduce any twisting forces , and our observations that the pharynges of 6-day old adult mnm-4 mutants twist no more than that of 1-day old adults , and that mnm-4 L1 larvae kept in M9 for 72 hours show no twist indicate that pumping , at least if not accompanied by growth , plays a minor role , if any , in the development of the pharyngeal twist . Twisting occurs very gradually as the animal and pharynx grows . [Field: discussion, subscore: 1.00]
SECTION: discussion. As the pharynx rhythmically contracts , the actomyosin array foreshortens radially to expand and contract the pharyngeal lumen . [Field: discussion, subscore: 1.00]
SECTION: discussion. The pharynx features two prominent cytoskeletal filamentous arrays , both of which are oriented in a radial fashion . [Field: discussion, subscore: 1.00]
SECTION: discussion. Therefore the phenotype likely originates from a relatively minor intrinsic defect within the mutant pharynx . [Field: discussion, subscore: 1.00]
SECTION: discussion. Thus it seems that the twisted pharynx of the studied mutants is functional and properly anchored to the rest of the worm body . [Field: discussion, subscore: 1.00]
SECTION: discussion. We examined several parameters relevant to understanding the twisted pharynx phenotype . [Field: discussion, subscore: 1.00]
SECTION: discussion. Arrows point to the anterior end of the pharynx . [Field: discussion, subscore: 1.00]
SECTION: discussion. Shown are DIC images of L1 larvae of the indicated genotypes and in which the pharynx has detached from the lips and moved posteriorly . [Field: discussion, subscore: 1.00]
SECTION: discussion. Pharynx regions are as follows ( metacorpus in A ; isthmus in B ; isthmus in C and D ) . [Field: discussion, subscore: 1.00]
SECTION: discussion. The basal lamina of the ectodermal cells can not be easily distinguished from this flocculent matrix , whereas the very thick basal lamina of the pharynx is now visible as a prominent electron dense line . [Field: discussion, subscore: 1.00]
SECTION: discussion. Radial muscle filaments have developed and the pharynx is now contractile . [Field: discussion, subscore: 1.00]
SECTION: discussion. Transverse thin section through the head indicates the region between the pharynx ( Ph ) and bodywall where basal lamina deposition is taking place ( arrowheads point to plasma membrane of body-wall ectodermal cells in each panel ) . [Field: discussion, subscore: 1.00]
SECTION: discussion. Discussion The twisted pharynx is a viable phenotype that worsens during post-embryonic development . [Field: discussion, subscore: 1.00]
SECTION: introduction. The aim of the present study was to better understand the twisted pharynx phenotype and its relationship to extracellular matrix components . [Field: introduction, subscore: 1.00]
SECTION: introduction. Finally , the mnm-4 mutant was isolated in a screen for abnormal morphology of the M2 pharyngeal neurons , and also has a twisted pharynx [ 12 ] . [Field: introduction, subscore: 1.00]
SECTION: introduction. Interestingly , a mutation in the other C . elegans septin , unc-59 , does not cause a twisted pharynx ; this is thus one of thefew phenotypes for which unc-59 and unc-61 differ [ 11 ] . [Field: introduction, subscore: 1.00]
SECTION: introduction. The uncoordinated mutant unc-61 also has a twisted pharynx . [Field: introduction, subscore: 1.00]
SECTION: introduction. Several C . elegans mutants have been reported to exhibit a twisted pharynx phenotype . [Field: introduction, subscore: 1.00]
SECTION: introduction. There are 80 cell nuclei from five cell types present in the pharynx : muscle cells , nerve cells , marginal cells , epithelial cells and gland cells [ 1 , 2 ] . [Field: introduction, subscore: 1.00]
SECTION: introduction. Background The pharynx is a simple muscular epithelial tube responsible for the ingestion and maceration of food in C . elegans . [Field: introduction, subscore: 1.00]
SECTION: introduction. The twisted pharynx is a useful and easy-to-score phenotype for genes required in extracellular adhesion or organ attachment , and perhaps forgenes required for cytoskeleton regulation . [Field: introduction, subscore: 1.00]
SECTION: introduction. In a mini screen of adhesionmolecule mutants , we also identified one more twisting pharynx mutant , sax-7 . [Field: introduction, subscore: 1.00]
SECTION: introduction. : We find that the twisting phenotype worsens throughout larval development , that in most mutants the pharynx retains its twist when dissected away from the worm body , and that double mutants between mnm-4 and mutants with thickened pharyngeal domains ( pha-2 and sma- 1 ) have less twisting in these regions . [Field: introduction, subscore: 1.00]
SECTION: introduction. Several C . elegans mutants have been reported to exhibit a twisted pharynx phenotype but no careful studies have been made to directly address this phenomenon . [Field: introduction, subscore: 1.00]
SECTION: introduction. Background : The pharynx of C . elegans is an epithelial tube whose development has been compared to that of the embryonic heart and the kidney and hence serves as an interesting model for organ development . [Field: introduction, subscore: 1.00]
SECTION: introduction. BMC Developmental Biology Research article The twisted pharynx phenotype in C . elegans Claes Axng1 , Manish Rauthan1 , David H Hall Address : 1Dept . of Chemical and Biological Engineering , Lundberg Laboratory , Chalmers University , Box 462 , S-405 30 , Gteborg , Sweden , Neuroscience , Albert Einstein College of Medicine , Bronx , New York , NY 10461 , USA and Box 462 , S-405 30 , Gteborg , Sweden Email : Claes Axng - claes . axang @ molbiotech . chalmers . se ; Manish Rauthan - manish . rauthan @ cmb . gu . se ; David H Hall - hall @ aecom . yu . edu ; Marc Pilon * - marc . pilon @ cmb . gu . se * Corresponding author Abstract [Field: introduction, subscore: 1.00]
SECTION: materials. The worms were thereafter mounted on agarose pad ( 2 % agarose in M9 buffer ) in a drop of 100 mM levamisol , covered with a cover slip and scored for the presence beads in the intestine and the pharynx using epifluorescence microscopy at 400 magnification . [Field: materials, subscore: 1.00]
SECTION: references. Raizen DM , Avery L : Electrical activity and behavior in the pharynx of Caenorhabditis elegans . [Field: references, subscore: 1.00]
SECTION: references. Mrck C , Axng C , Pilon M : A genetic analysis of axon guidance in the C . elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. Portereiko MF , Mango S : Early morphogenesis of the Caenorhabditis elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. Avery L , Shtonda BS : Food transport in the C . elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. Albertson DG , Thomson JN : The pharynx of Caenorhabditis elegans . [Field: references, subscore: 1.00]
SECTION: results. The dashed line indicates the border between the pharynx ( to the left ) and intestine . [Field: results, subscore: 1.00]
SECTION: results. Wild-type ( N2 ) and mnm-4 mutant adults expressing ajm-1 : : gfp reporter were photographed to reveal not only the twisting within the pharynx of the mutant , but also the opposite twist in its anterior intestine . [Field: results, subscore: 1.00]
SECTION: results. One hypothesis is that the twisting force is already present in early larval stages but that its effect is hampered by attachment of the pharynx to surrounding it issue ( see previous section ) . [Field: results, subscore: 1.00]
SECTION: results. It is uncertain whether this accessory pseudocoelom is continuous with the pseudocoelom proper , due to close approach to the pharynx by GLR processes beneath the nerve ring [ 1 , 18 ] . [Field: results, subscore: 1.00]
SECTION: results. Only in larvae and adults can a distinct " accessory pseudocoelomic space " be seen that separates the thin ectodermal basal laminae from the thick basal lamina of the pharynx ( Fig . 7CD ) . [Field: results, subscore: 1.00]
SECTION: results. This suggests that appreciable friction between bodywall and pharyngeal it issues may hold the pharynx in place prior to the onset of pumping in the L1 , and may thus restrict onset of the twisting phenotype . [Field: results, subscore: 1.00]
SECTION: results. Compared to more posterior regions of the body cavity , this tightness remains a feature of the head throughout development , but some minimal separation does develop to accommodate vigorous motions of the pharynx during feeding . [Field: results, subscore: 1.00]
SECTION: results. Direct contact between the basal laminae of the pharynx and body-wall is very tight in the embryo Multiple studies of C . elegans embryos , including our own , have shown practically no available space between the mesodermal layers and ectodermal layers prior to hatching ( Fig . 7 ) . [Field: results, subscore: 1.00]
SECTION: results. More tenuously , the cuticle lining of the pharynx is also continuous with the bodywall cuticle in the region of the arcade cells ( buccal cavity ) . [Field: results, subscore: 1.00]
SECTION: results. BMC Developmental Biology 2007 , 7 : 61 http : / / www . biomedcentral . com / 1471-213X / 7 / 61 Page 7 of 13 ( page number not for citation purposes ) that the foremost intestinal cells twist in a direction opposite to the pharynx , hence relieving the tension induced by the pharyngeal twist ( Fig . 6 ) . [Field: results, subscore: 1.00]
SECTION: results. Because it is tilted with respect to the body axis , the tendon is better seen close to the pharynx in this image , but goes out of the plane of section as it passes between the muscle cells . [Field: results, subscore: 1.00]
SECTION: results. In ( B ) , note that strong degrees of twist can be detected in both the procorpus ( leftmost portion ) and at the isthmus between the two bulbs in the mutant pharynx , but only subtle twisting within each bulb . [Field: results, subscore: 1.00]
SECTION: results. Note that in all the specimens , the actin filaments are evenly spaced and generally aligned near-perpendicularly to the longitudinal axis of the pharynx if it were untwisted . [Field: results, subscore: 1.00]
SECTION: results. Indeed , when the twist is visualized using ajm1 : gfp in the mnm-4 background , the pharynx seems to have rotated at the posterior end around the terminal bulb passively dragging the intestine with it , such The actin cytoskeleton is twisted and lengthened in twisted pharynges Figure 5 The actin cytoskeleton is twisted and lengthened in twisted pharynges . [Field: results, subscore: 1.00]
SECTION: results. Number of beads in the intestine : 27 . 1 7 . 4 for N2 , and 30 . 8 7 . 7 ( n = 35 ) , indicating a similar transfer rate of beads from the pharynx to the intestine in the two genotypes . [Field: results, subscore: 1.00]
SECTION: results. Number of beads counted in the pharynx : 64 . 6 9 . 3 for N2 , and 78 . 1 11 . 4 ( n = 19 ) , indicating a similar steady-state number of beads in the two genotypes ; ( B ) Overlays of a DIC image and an epifluorescence image of thefluorescent beads in the intestine swallowed during a brief 2 min period . [Field: results, subscore: 1.00]
SECTION: results. ( A ) Overlays of a DIC image and an epifluorescence image of the fluorescent beads present in the pharynx following a feeding period of 30 minutes . [Field: results, subscore: 1.00]
SECTION: results. This is interesting since misregulation of filament length in growing pharyngeal muscles may be a cause of twisting : long actin filaments may be accommodated by twisting the pharynx . [Field: results, subscore: 1.00]
SECTION: results. Thus the whole pharynx , including its basal lamina to which the tendons are attached , is twisted in mutants . [Field: results, subscore: 1.00]
SECTION: results. As shown in Fig . 4C , the pharyngeal tendons are attached to the basal lamina that surrounds the pharynx and project between the bodywall muscle cells in each muscle quadrant , then connect on their opposite ends to the basement membranes running between bodywall muscles and thin extensions of the hypodermal cells , near the cuticle . [Field: results, subscore: 1.00]
SECTION: results. ( A ) An example of a twisted pharynx and the three measurements that can be obtained by DIC microscopy to estimate the actual degree of twist within the isthmus using the formula shown on the right side ( D is diameter ; L is isthmus length ; and is the angle between the torsion lines and the pharyngeal axis ) . [Field: results, subscore: 1.00]
SECTION: results. Panels G-J show the pharyngeal twist in mnm-4 animals carrying mutations that cause abnormal pharynx morphologies ( pha-2 , sma-1 ) or reduced pumping rate ( eat-3 ) . [Field: results, subscore: 1.00]
SECTION: results. However , eat-3 ; mnm-4 double mutants also showed a 10 % reduction in pharyngeal length ( " L " in Fig . 1A ) compared with mnm-4 mutants , and this may have contributed to the decrease in twist if growth of the pharynx is important . [Field: results, subscore: 1.00]
SECTION: results. * Only those dig- 1 and mig-4 worms with a pharyngeal were used to calculate the average twist of these mutants . http : / / www . biomedcentral . com / 1471-213X / 7 / 61 Page 3 of 13 ( page number not for citation purposes ) severely twisted pharynx ( etIs2 ; mnm-4 ; 3 . 7 0 . 3 pumps per second ) . [Field: results, subscore: 1.00]
SECTION: results. The pharynx of dig-1 and unc-61 mutants occasionally straightens ( 2 of 15 and 3 of 16 dissected pharynges , respectively ) when separated from the worm . [Field: results, subscore: 1.00]
SECTION: results. The result is also consistent with the twisting force being intrinsic to the pharynx itself . [Field: results, subscore: 1.00]
SECTION: results. This result does not exclude the possibility that the twist originates from outside the pharynx , but it shows that the twist has become irreversible by the time of dissection . [Field: results, subscore: 1.00]
SECTION: results. Conversely , the pharynx of unc-61 , mig-4 , dig-1 and mnm-4 mutant worms mostly keep their twisted shape after being dissected ( Fig . 2AF ) . [Field: results, subscore: 1.00]
SECTION: results. They were then scored for the presence and extent of twist . We found that the pharynx of wild-type worms does not twist when dissected away from the body . [Field: results, subscore: 1.00]
SECTION: results. Pharyngeal twist is retained in isolated pharynges , and thickened pharyngeal parts resist twisting We were interested to test whether the force causing twisting is an intrinsic property of the organ or originates from outside the pharynx . [Field: results, subscore: 1.00]
SECTION: results. This result suggests that these three genes may either interact directly or are involved in multiple steps in a single developmental process during larval growth of the pharynx . [Field: results, subscore: 1.00]
SECTION: results. Worms heterozygous for the mnm-4 mutation also exhibited a twisted pharynx , although the twist was less pronounced than in age-matched homozygous mutants ( Table 1 ) . [Field: results, subscore: 1.00]
SECTION: results. Properties of the twisted pharynx phenotype We began by studying the mnm-4 mutant and found that its pharyngeal twist is first visible post-embryonically and increases during development throughout the larval stages , rather than only in sudden jumps during molting , to reach its maximum during the fourth larval stage ( Fig . 1 ; Table 1 ) . [Field: results, subscore: 1.00]
SECTION: title. The twisted pharynx phenotype in C . elegans . [Field: title, subscore: 1.00]
Supplemental links/files: reference in endnote reference in xml Wormbase reference
Score: 112.00
Title: The molecular basis of organ formation : insights from the C . elegans foregut .
Authors: Mango S
Journal: Annu Rev Cell Dev Biol
Year: 2009
Doc ID: WBPaper00034711
Bibliographic Information
Abstract
Matching Sentences
SECTION: references. ANRV389-CB25-24 ARI 12 September 2009 9 : 11 MS ara alp P2 EMS ABp ABa arap araa alpa MSaa MSpa MS ara alp P2 EMS ABp ABa arap araa alpa MSaa MSpa Pharynx Neurons Epidermis Pharynx Neurons Epidermis Pharynx Neurons Pharynx Neurons Pharynx Pharynx Gonad Body wall muscle Midgut Pharynx Gonad Body wall muscle Pharynx Body wall muscle Pharynx Neurons Epidermis skn-1 skn-1 med-1 / 2 a 4-cell b 8-cell c 28-cell med-1 / 2 tbx-35 pha-4 glp-1 lag-1 tbx-37 / 38 pha-4 glp-1 lab-1 ref-1 Figure 3 Early developmental pathways . [Field: references, subscore: 9.00]
SECTION: references. Aph : anterior pharynx absent , Daf : dauer defective , M / Z : maternal or zygotic contribution of RNA or protein , P ha : pharynx absent , pm : pharyngeal muscle , PPa : posterior pharynx absent , Pun : pharynx unattached , Rcp : receptor , TF : transcription factor , Zn : zinc , ? [Field: references, subscore: 4.00]
SECTION: abstract. Here , I focus on the processes that specify cell fates and control morphogenesis within the embryonic foregut ( pharynx ) and the developmental roles of the pharynx after birth . [Field: abstract, subscore: 2.00]
SECTION: introduction. In the absence of skn-1 , no pharynx is produced because MS and E are transformed into their cousin the C blastomere , which neither generates pharynx nor produces Notch ligands to signal to AB descendants . [Field: introduction, subscore: 2.00]
SECTION: introduction. The pharynx is a bilobed , linear tube that is organized into three sections : At the anterior , the corpus pumps food ( bacteria ) into the pharynx and concentrates it by expelling excess water . [Field: introduction, subscore: 2.00]
SECTION: introduction. ANATOMY OF THE MATURE PHARYNX Ultrastructural studies have provided an indepth view of pharynx architecture ( Albertson Thomson 1976 ) . [Field: introduction, subscore: 2.00]
SECTION: introduction. Here , I focus on the processes that specify cell fates and control morphogenesis within the embryonic foregut ( pharynx ) and the developmental roles of the pharynx after birth . [Field: introduction, subscore: 2.00]
SECTION: references. PHA-4 AND THE PHARYNX AFTER BIRTH : AGING Most studies of pha-4 and the pharynx have focused on embryonic roles , but recent data implicate this pair for postembryonic life . [Field: references, subscore: 2.00]
SECTION: references. The spotty conservation between C . elegans and vertebrates has led some to suggest the C . elegans pharynx is the cognate of the vertebrate heart , but parallels between the heart and pharynx likely reflect convergent evolution and not conservation ( discussed in-depth in Mango 2007 ) . [Field: references, subscore: 2.00]
SECTION: references. pha-4 is the central regulator of pharynx development and the only zygotic gene that deletes the entire pharynx when mutated ( Figure 3 ) ( Horner et al . 1998 , Kalb et al . 1998 , Mango et al . 1994 ) . [Field: references, subscore: 2.00]
SECTION: references. For example , GLP-1 / Notch signaling represses pharynx development in AB descendants at the 4-cell stage but induces pharynx development in these same cells at the 12-cell stage , which depends on the presence or absence of TBX-37 and TBX-38 . [Field: references, subscore: 2.00]
SECTION: abstract. After birth , the pharynx and / or pha-4 are involved in repelling pathogens and controlling aging . [Field: abstract, subscore: 1.00]
SECTION: introduction. ANRV389-CB25-24 ARI 12 September 2009 9 : 11 T able 1 Summary of genes involved in pharynx development Gene Homology M / Z Expression ( initiation ) Pha phenotype T argets Binding sequence Upstream genes [Field: introduction, subscore: 1.00]
SECTION: introduction. Conversely , mutants with ectopic SKN-1 activity produce extra MS-like cells and ectopic pharynx , revealing an instructive role for the SKN-1 protein ( Mello et al . 1992 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. PHA-4 is the central selector regulator for the pharynx and its activity is essential for all pharyngeal development ( Mango et al . 1994 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. All ABa descendants activate tbx-37 and tbx-38 expression , rendering these blastomeres competent to produce pharynx in response to inductive cues . [Field: introduction, subscore: 1.00]
SECTION: introduction. tbx-37 and tbx-38 constitute a pair of redundant factors that are critical to produce pharynx from the AB lineage ; their absence ensures that no ABp descendants generate pharyngeal cells in wild-type embryos ( Good et al . 2004 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. The distinction in pharynx production depends on the ref-1 family of bHLH transcription factors , which are induced only in ABp by GLP-1 / Notch signaling ( Figure 3 ) ( Neves Priess 2005 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. Independent pathways specify AB and MS and control their ability to produce pharynx ( reviewed in Mango 2007 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. Subsequently , additional it issue and lineage-restricted factors establish different cell types within the pharynx in combination with PHA-4 . [Field: introduction, subscore: 1.00]
SECTION: introduction. ANRV389-CB25-24 ARI 12 September 2009 9 : 11 Epidermis Neurons Pharynx Muscle ABarp ABala ABara MS ABpla E ABalp ABplp D C Gut a b c d Figure 2 Two zygotic patterning systems . [Field: introduction, subscore: 1.00]
SECTION: introduction. ( b ) The bulk of the pharynx is composed of eight layers of muscles ( pm18 ) ( green ) and three groups of structural marginal cells ( mc13 ) ( purple ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. ( a ) Nuclei within the pharynx are shown as muscles ( red ) , neurons ( purple ) , epithelia ( orange ) , marginal cells ( pink ) , and glands ( brown ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. Rather than lineage , cells within this domain are united to each other by their pharyngeal identity and the homogeneous ---------------------------------- Figure 1 Pharynx anatomy . [Field: introduction, subscore: 1.00]
SECTION: introduction. This system functions reiteratively and helps specify the founder cells in the pregastrula embryo , the pharyngeal precursors at the onset of gastrulation , and cell types within the pharynx during the terminal cleavage stages . [Field: introduction, subscore: 1.00]
SECTION: introduction. CELL FATE SPECIFICATION DURING EMBRYOGENESIS Overview To build the mature pharynx , C . elegans embryos first establish a pool of pharyngeal precursors and subsequently specify different cell-type identities such as pharyngeal muscle or pharyngeal gland . [Field: introduction, subscore: 1.00]
SECTION: introduction. At the anterior , the pharynx attaches to the buccal cavity and epidermis with three rings of arcade cells and epithelial cells . [Field: introduction, subscore: 1.00]
SECTION: introduction. These additions help propel bacteria down the pharynx and crush them to initiate the digestion process . [Field: introduction, subscore: 1.00]
SECTION: introduction. The bulk of the pharynx is composed of eight sections of muscles , pm1-pm8 , that are positioned as rings along the longitudinal axis ( Figure 1 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. The pharynx is made up of 95 cells grouped into seven cell types : arcade cells , muscle or myoepithelial cells , epithelia , neurons , glands , marginal cells , and valves ( Albertson Thomson 1976 , Horner et al . 1998 ) . [Field: introduction, subscore: 1.00]
SECTION: introduction. With the ability to visualize individual cells during organogenesis and the development of powerful genetic and genomic tools , scientists have begun to dissect the pathways that control cell fate specification , morphogenesis , and postembryonic roles of the pharynx . [Field: introduction, subscore: 1.00]
SECTION: introduction. To form the pharynx , C . elegans faces developmental challenges that are similar to organ formation in more complex animals . [Field: introduction, subscore: 1.00]
SECTION: introduction. 614 PHA-4 AND THE PHARYNX AFTER BIRTH : AGING . [Field: introduction, subscore: 1.00]
SECTION: introduction. 598 ANATOMY OF THE MATURE PHARYNX . [Field: introduction, subscore: 1.00]
SECTION: introduction. After birth , the pharynx and / or pha-4 are involved in repelling pathogens and controlling aging . [Field: introduction, subscore: 1.00]
SECTION: references. The Caenorhabditis elegans peb- 1 gene encodes a novel DNA-binding protein involved in morphogenesis of the pharynx , vulva , and hindgut . [Field: references, subscore: 1.00]
SECTION: references. The Fat-like cadherin CDH-4 controls axon fasciculation , cell migration and hypodermis and pharynx development in Caenorhabditis elegans . [Field: references, subscore: 1.00]
SECTION: references. AST-1 , a novel ETS-box transcription factor , controls axon guidance and pharynx development in C . elegans . [Field: references, subscore: 1.00]
SECTION: references. Early morphogenesis of the Caenorhabditis elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. The C . elegans pharynx : a model for organogenesis . [Field: references, subscore: 1.00]
SECTION: references. pha-4 is Ce-fkh-1 , a fork head / HNF- 3alpha , beta , gamma homolog that functions in organogenesis of the C . elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. Interference between the PHA-4 and PEB-1 transcription factors in formation of the Caenorhabditis elegans pharynx . [Field: references, subscore: 1.00]
SECTION: references. C . elegans agrin is expressed in pharynx , IL1 neurons and distal tip cells and does not genetically interact with genes involved in synaptogenesis or muscle function . [Field: references, subscore: 1.00]
SECTION: references. Sarcopenia in the Caenorhabditis elegans pharynx correlates with muscle contraction rate over lifespan . [Field: references, subscore: 1.00]
SECTION: references. A fork head / HNF-3 homolog expressed in the pharynx and intestine of the Caenorhabditis elegans embryo . [Field: references, subscore: 1.00]
SECTION: references. The Caenorhabditis elegans ems class homeobox gene ceh-2 is required for M3 pharynx motoneuron function . [Field: references, subscore: 1.00]
SECTION: references. Transcription factors GATA / ELT-2 and forkhead / HNF-3 / PHA-4 regulate the tropomyosin gene expression in the pharynx and intestine of Caenorhabditis elegans . [Field: references, subscore: 1.00]
SECTION: references. The pharynx of Caenorhabditis elegans . [Field: references, subscore: 1.00]
SECTION: references. Finally , the involvement of the pharynx and pharyngeal factors in immunity and aging is a recent discovery , and there are a host of unanswered questions . [Field: references, subscore: 1.00]
SECTION: references. During morphogenesis , a future goal is to determine how to form epithelia by pathways that do not require cadherins or integrins and how to shape those epithelia into the distinctive morphologies of the mature pharynx . [Field: references, subscore: 1.00]
SECTION: references. We have only a rudimentary understanding of how different cell types are established during the terminal stages of pharynx development . [Field: references, subscore: 1.00]
SECTION: references. More recently , the pharynx and pha-4 have emerged as regulators of post-embryonic processes , notably aging and the immune response , both in adults . [Field: references, subscore: 1.00]
SECTION: references. During mid-embryogenesis the pharynx precursors undergo a mesenchymal to epithelial transition ( MET ) , which is the first step of tube formation . [Field: references, subscore: 1.00]
SECTION: references. Commitment to pharyngeal fate depends on positive feedback loops between the central regulator of the pharynx , pha-4 / FoxA , and additional transcriptional regulators on positive autoregulation by transcription factors and on negative repression of factors that dictate alternative fates . [Field: references, subscore: 1.00]
SECTION: references. The C . elegans pharynx offers a powerful system to track organogenesis from the earliest stages of embryonic cell fate specification to the final stages of aging and death . [Field: references, subscore: 1.00]
SECTION: references. The inactivation of any of these factors allows S . enterica to invade the pharynx and leads to death . [Field: references, subscore: 1.00]
SECTION: references. Resistence of the pharynx to infection depends on the CED- 1 and TOL-1 receptors and a noncanonical unfolded protein response ( UPR ) ( Haskins et al . 2008 , Tenor Aballay 2008 , Troemel et al . 2006 ) . [Field: references, subscore: 1.00]
SECTION: references. The pharynx participates in the immune response by physically crushing bacteria with the pharygneal grinder and secreting antimicrobial peptides ( Millet Ewbank 2004 ) . [Field: references, subscore: 1.00]
SECTION: references. ANRV389-CB25-24 ARI 12 September 2009 9 : 11 In addition to aging , the pharynx is susceptible to pathogens such as Salmonella enterica ( Millet Ewbank 2004 ) . [Field: references, subscore: 1.00]
SECTION: references. However , PHA-4 is expressed in other organs as well as the pharynx , namely the gonad , the intestine , and parts of the nervous system ( Azzaria et al . 1996 , Chen Riddle 2008 , Horner et al . 1998 ) , all of which are involved in lifespan ( Mukhopadhyay Tissenbaum 2007 ) . [Field: references, subscore: 1.00]
SECTION: references. The rate of pharyngeal pumping declines with age ( Bolanowski et al . 1981 , Huang et al . 2004 ) , and the pharynx exhibits sarcopenia with loss and damage of muscles ( Chow et al . 2006 , Garigan et al . 2002 , Herndon et al . 2002 ) . [Field: references, subscore: 1.00]
SECTION: references. The pharynx ages over time , which could contribute to the health and longevity of animals . [Field: references, subscore: 1.00]
SECTION: references. M / Z : maternal or zygotic contribution , phx : pharyngeal , Pun : pharynx unattached , ? [Field: references, subscore: 1.00]
SECTION: references. ten-1 Teneurin Z Pharynx Basement membrane Trzebiatowska et al . 2008 ubc-18 Ubiquitin conj ez ? [Field: references, subscore: 1.00]
SECTION: references. Non-Pha , epidermis crp-1 cdc-42 related Z Muscles and nonphx epithelia cyk-4 MgcRacGAP M , Z Broadly RhoGAP die-1 Zinc finger TF Z Epithelia , pharynx eff-1 Novel Z Muscles , nonphx fusing epithelia , vpi elt-5 / egl-18 GATA TF Z Nonpha epidermis , neurons fbl-1 Fibulin Z Nonphx ham-2 Zinc finger Z Embryo Inx-3 Innexin Z Broadly , epithelia let-413 Scribble Z Epithelia lin-35 Rb repressor ? [Field: references, subscore: 1.00]
SECTION: references. ANRV389-CB25-24 ARI 12 September 2009 9 : 11 Table 2 Genes involved in pharyngeal morphogenesis Gene Homology M / Z Cellular expression aff-1 Novel fusogen , eff-1 Z pm8 agr-1 Agrin Z Buccal cavity , arcade cells , pharynx ari-1 Ariadne RING finger ? [Field: references, subscore: 1.00]
SECTION: references. pha-4 is required after birth for the development of both the pharynx and gonad ( Ao et al . 2004 , Gaudet Mango 2002 , Updike Mango 2007 ) . [Field: references, subscore: 1.00]
SECTION: references. Mutations in ten-1 teneurin and nid-1 nidogen disrupt the basement membrane surrounding the pharynx ( Trzebiatowska et al . 2008 ) . [Field: references, subscore: 1.00]
SECTION: references. cdh-4 and its paralog cdh-3 encode Fat-like cadherins with cadherin , laminin G , and EGF domains ; and both are expressed in the pharynx ( Pettitt et al . 1996 , Schmitz et al . 2008 ) . [Field: references, subscore: 1.00]
SECTION: references. ANRV389-CB25-24 ARI 12 September 2009 9 : 11 In addition to these well-characterized examples , there are additional factors that affect pharynx morphogenesis by unknown processes such as cell fate , differentiation , or morphogenesis ( Table 2 ) . [Field: references, subscore: 1.00]
SECTION: references. Little is known about the processes that dictate pharyngeal cell shapes with the exception of pm8 . pm8 is a toroid-shaped muscle that links the pharynx to the pharyngeal intestinal valve and intestine . [Field: references, subscore: 1.00]
SECTION: references. The basement membrane surrounding the pharynx is denoted by a dotted yellow line in both sets of panels . [Field: references, subscore: 1.00]
SECTION: references. These events produce a continuous pharyngeal epithelium ; subsequent events shape the pharynx into a bilobed tube . [Field: references, subscore: 1.00]
SECTION: references. Finally , in the third step , the cells of the pharynx , buccal cavity , and epidermis appear to contract their apical surfaces , which pulls the cells more closely together . [Field: references, subscore: 1.00]
SECTION: references. In the second step the arcade cells undergo a mesenchymal to epithelial transition , which establishes a continuous epithelium between the epidermis and the pharynx ( Figure 6 ) . [Field: references, subscore: 1.00]
SECTION: references. Additional analysis of promoter structures will reveal if these distinctions continue to hold true for the pharynx and intestine . [Field: references, subscore: 1.00]
SECTION: references. Thus , the simplicity of the intestine is mirrored with a simpler transcriptional strategy compared to the pharynx : potent transcription factors , less consensus sequence heterogeneity , and simpler promoter architecture . [Field: references, subscore: 1.00]
SECTION: references. Unlike the pharynx , the intestine is a simple organ composed of one cell type that derives from a single blastomere called E ( Sulston et al . 1983 ) . [Field: references, subscore: 1.00]
SECTION: references. In the pharynx , the strength of expression depends on combinatorial regulation with other transcription factors , and not PHA-4-binding-site affinity ( Ao et al . 2004 , Gaudet Mango 2002 , Gaudet et al . 2004 ) . [Field: references, subscore: 1.00]
SECTION: references. In some instances , affinity contributes to temporal control , as it does for the pharynx . [Field: references, subscore: 1.00]
SECTION: references. Otx is critical for endoderm development in echinoderms ( Hinman et al . 2003 ) , but no gut role is known for Otx factors in C . elegans despite its expression in the pharynx and intestine ( Hobert 2005 , Lanjuin et al . 2003 ) . [Field: references, subscore: 1.00]
SECTION: references. The interdependence of PHA-4 and either HLH-6 or TBX-2 suggests that commitment to pharyngeal identity is intimately linked to cell type specification within the pharynx . [Field: references, subscore: 1.00]
SECTION: references. A blastomere fated to produce pharynx , for example , can instead give rise to epidermis or muscle ( Fukushige Krause 2005 , Gilleard McGhee 2001 , Kiefer et al . 2007 ) . [Field: references, subscore: 1.00]
SECTION: references. ANRV389-CB25-24 ARI 12 September 2009 9 : 11 suggests that the function of pha-4 is to specify organ identity within the pharynx ( Horner et al . 1998 ) . [Field: references, subscore: 1.00]
SECTION: references. This dramatic phenotype reflects the direct involvement of PHA-4 in transcribing many , and perhaps all , genes selectively transcribed in the pharynx , including early acting developmental regulators and terminal differentiation genes that encode structural proteins and digestive enzymes ( Anokye-Danso et al . 2008 , Gaudet Mango 2002 , Kalb et al . 1998 , Mango 2007 , Morck et al . 2004 , Raharjo Gaudet 2007 , Vilimas et al . 2004 ) . [Field: references, subscore: 1.00]
SECTION: references. LAG-1 , TBX-35 , TBX-37 / 38 , and the MED factors contribute to the transition--their mutant phenotypes affect cell lineages ( e . . , MS ) --but their downstream targets , described below , are geared towards tissues and organs such as MS-derived pharynx or muscle ( Broitman-Maduro et al . 2006 , Good et al . 2004 , Maduro et al . 2005a , Smith Mango 2007 ) . [Field: references, subscore: 1.00]
SECTION: references. One of the first signs of integration is that cells from different lineages but similar fates ( e . . , pharynx ) cluster together within the gastrulating embryo . [Field: references, subscore: 1.00]
SECTION: references. As this phase gets under way , cells destined to produce the pharynx and that derive from different cell lineages coordinate their development to form an integrated organ ( Figure 2 ) . [Field: references, subscore: 1.00]
SECTION: references. The pharynx is generated from a subset of blastomeres ( green ) ( i . . , ABa and EMS at the 4-cell stage ) . [Field: references, subscore: 1.00]
SECTION: references. For the pharynx , the best-described role of the A-P patterning system is to distinguish the anterior MS founder cell from its posterior sister E . This system depends on the Lef transcription factor POP-1 and its cofactor SYS-1 / b-catenin ( Huang et al . 2007 ; Kidd et al . 2005 ; Lin et al . 1995 , 1998 ; Phillips et al . 2007 ) ( reviewed in Eisenmann 2005 , Mizumoto Sawa 2007 ) . [Field: references, subscore: 1.00]
SECTION: references. Y anowitz et al . 2004 arc metacorpus Genes that are implicated in pharynx development are listed from earliest stages of specification to later events . [Field: references, subscore: 1.00]
SECTION: references. Aspock et al . 2003 ceh-22 Nkx 2 . 2 Homeobox TF Z pm35 , pm7 Indistinct BM around pharynx myo-2 CACTT A T pha-4 ceh-22 ceh-2 pha-2 Kalb et al . 1998 , Mango et al . 1994 , Okkema Fire 1994 , Okkema et al . 1997 ceh-24 Nkx 2 . 3 TF Z pm8 None ? [Field: references, subscore: 1.00]
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