title: mab-20 encodes Semaphorin-2a and is required to prevent ectopic cell contacts during epidermal morphogenesis in Caenorhabditis elegans.
abstract: The Semaphorins are a family of secreted and transmembrane proteins known to elicit growth cone repulsion and collapse. We made and characterized a putative null mutant of the C. elegans gene semaphorin-2a (Ce-sema-2a). This mutant failed to complement mutants of mab-20 (Baird, S. E., Fitch, D. H., Kassem, I. A. A. and Emmons, S. W. (1991) Development 113, 515-526). In addition to low-frequency axon guidance errors, mab-20 mutants have unexpected defects in epidermal morphogenesis. Errant epidermal cell migrations affect epidermal enclosure of the embryo, body shape and sensory rays of the male tail. These phenotypic traits are explained by the formation of inappropriate contacts between cells of similar type and suggest that Ce-Sema-2a may normally prevent formation or stabilization of ectopic adhesive contacts between these cells.
authors.affiliation: Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada.
authors.forename: P J
authors.initials: PJ
authors.lastname: Roy
authors.forename: H
authors.initials: H
authors.lastname: Zheng
authors.forename: C E
authors.initials: CE
authors.lastname: Warren
authors.forename: J G
authors.initials: JG
authors.lastname: Culotti
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology* / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D002448:Cell Adhesion / Q000235:genetics; D002465:Cell Movement / Q000235:genetics; D003001:Cloning, Molecular; D000078404:Epidermal Cells; D004817:Epidermis / Q000196:embryology; D018507:Gene Expression Regulation, Developmental; D017238:Genes, Helminth; D005816:Genetic Complementation Test; D015801:Helminth Proteins / Q000235:genetics*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D009414:Nerve Growth Factors / Q000235:genetics*; D009419:Nerve Tissue Proteins / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013623:Tail / Q000196:embryology
chemical_list: D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; D008565:Membrane Proteins; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; C405025:mab-20 protein, C elegans