title: xGit2 and xRhoGAP 11A regulate convergent extension and tissue separation in Xenopus gastrulation.
abstract: In a microarray-based screen for genes that are involved in tissue separation downstream of Paraxial Protocadherin (PAPC) and Frizzled-7 (Fz7)-mediated signaling we identified xGit2 and xRhoGAP 11A, two GTPase-activating proteins (GAP) for small GTPases. xGit2 and xRhoGAP 11A are expressed in the dorsal ectoderm, and their transcription is downregulated in the involuting dorsal mesoderm by PAPC and Fz7. Overexpression of xGit2 and xRhoGAP 11A inhibits Rho activity and impairs convergent extension movements as well as tissue separation behaviour. We propose that Rho activity in the involuting mesoderm is enhanced through inhibition of xGit2 and xRhoGAP 11A transcription by PAPC and Fz7. By this mechanism xRhoGAP 11A and xGit2 are restricted to the dorsal ectoderm, while Rho signaling is inhibited.
authors.affiliation: Institute of Human Genetics, University Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany. Isabelle.Koester@googlemail.com
authors.forename: Isabelle
authors.initials: I
authors.lastname: Köster
authors.forename: Maria S
authors.initials: MS
authors.lastname: Jungwirth
authors.forename: Herbert
authors.initials: H
authors.lastname: Steinbeisser
mesh_terms: D000818:Animals; D015509:Developmental Biology / Q000379:methods; D004475:Ectoderm / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism*; D005775:Gastrula / Q000378:metabolism*; D005786:Gene Expression Regulation; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008648:Mesoderm / Q000378:metabolism; D008954:Models, Biological; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D015398:Signal Transduction; D014158:Transcription, Genetic; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: C492040:Fzd7 protein, Xenopus; D020690:GTPase-Activating Proteins; C551348:Git2 protein, Xenopus; D043562:Receptors, G-Protein-Coupled; C551349:Rho GTPase activating protein 11A, Xenopus; D029867:Xenopus Proteins; C085379:rho GTPase-activating protein; D049452:Green Fluorescent Proteins