title: Semaphorin and Eph receptor signaling guide a series of cell movements for ventral enclosure in C. elegans.
abstract: BACKGROUND
  In the last stage of the Caenorhabditis elegans body wall closure, an open pocket in the epidermis is closed by the migration of marginal epidermal P/pocket cells to the ventral midline. The cellular and molecular mechanisms of this closure remain unknown.
  
  
  RESULTS
  Cells within the pocket align to form a bridge for migration of contralateral P cell pair P9/10 L,R (and neighboring P cells) to the midline. Bridge formation involves rearrangement of five sister pairs of PLX-2/plexin and VAB-1/Eph receptor expressing "plexin band" cells, of which three pairs form a scaffold for bridge assembly and two pairs form the bridge. Bridge formation requires VAB-1 kinase-dependent extension of presumptive bridge cells over scaffold cells toward the ventral midline. An unassembled vab-1 null mutant bridge obstructs P cell migration, which is largely overcome by plexin band expression of VAB-1 or VAB-1(delC) (a kinase deletion of VAB-1). VAB-1 also functions redundantly with MAB-20/semaphorin to prevent perdurant gaps between sister plexin band cells that block P cell migration.
  
  
  CONCLUSIONS
  The Eph receptor mediates cellular extensions required for bridge formation, independently facilitates P cell migration to the midline, and functions redundantly with PLX-2/plexin to prevent gaps in the bridge used for P9/10 cell migration in body wall closure.
authors.affiliation: Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5S 1A8, Canada.
authors.forename: Richard
authors.initials: R
authors.lastname: Ikegami
authors.forename: Kristin
authors.initials: K
authors.lastname: Simokat
authors.forename: Hong
authors.initials: H
authors.lastname: Zheng
authors.forename: Louise
authors.initials: L
authors.lastname: Brown
authors.forename: Gian
authors.initials: G
authors.lastname: Garriga
authors.forename: Jeff
authors.initials: J
authors.lastname: Hardin
authors.forename: Joseph
authors.initials: J
authors.lastname: Culotti
mesh_terms: D000818:Animals; D019521:Body Patterning; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000196:embryology* / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement; D004625:Embryo, Nonmammalian / Q000166:cytology; D000078404:Epidermal Cells; D004817:Epidermis / Q000196:embryology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D036082:Receptor, EphA1 / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D039961:Semaphorins / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C526375:Plx-2 protein, C elegans; D011956:Receptors, Cell Surface; D039961:Semaphorins; C405025:mab-20 protein, C elegans; D020794:Receptor Protein-Tyrosine Kinases; D036082:Receptor, EphA1; C111040:vab-1 protein, C elegans