title: The GEX-2 and GEX-3 proteins are required for tissue morphogenesis and cell migrations in C. elegans.
abstract: During body morphogenesis precisely coordinated cell movements and cell shape changes organize the newly differentiated cells of an embryo into functional tissues. Here we describe two genes, gex-2 and gex-3, whose activities are necessary for initial steps of body morphogenesis in Caenorhabditis elegans. In the absence of gex-2 and gex-3 activities, cells differentiate properly but fail to become organized. The external hypodermal cells fail to spread over and enclose the embryo and instead cluster on the dorsal side. Postembryonically gex-3 activity is required for egg laying and for proper morphogenesis of the gonad. GEX-2 and GEX-3 proteins colocalize to cell boundaries and appear to directly interact. GEX-2 and GEX-3 are highly conserved, with vertebrate homologs implicated in binding the small GTPase Rac and a GEX-3 Drosophila homolog, HEM2/NAP1/KETTE, that interacts genetically with Rac pathway mutants. Our findings suggest that GEX-2 and GEX-3 may function at cell boundaries to regulate cell migrations and cell shape changes required for proper morphogenesis and development.
authors.affiliation: Program in Molecular Medicine and Cell Biology, Howard Hughes Medical Institute, University of Massachusetts Cancer Center, Worcester, Massachusetts 01605, USA.
authors.forename: Martha C
authors.initials: MC
authors.lastname: Soto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Qadota
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Kasuya
authors.forename: Makiko
authors.initials: M
authors.lastname: Inoue
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tsuboi
authors.forename: Craig C
authors.initials: CC
authors.lastname: Mello
authors.forename: Kozo
authors.initials: K
authors.lastname: Kaibuchi
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000254:growth & development*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics; D002451:Cell Compartmentation; D002465:Cell Movement; D017124:Conserved Sequence; D029721:Drosophila Proteins; D017238:Genes, Helminth; D008969:Molecular Sequence Data; D009024:Morphogenesis; D010058:Oviposition / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D020744:rac GTP-Binding Proteins / Q000235:genetics
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D029721:Drosophila Proteins; C450821:GEX-2 protein, C elegans; C450822:GEX-3 protein, C elegans; C484666:Sra-1 protein, Drosophila; D020744:rac GTP-Binding Proteins