title: The small G-proteins Rac1 and Cdc42 are essential for myoblast fusion in the mouse.
abstract: Rac1 and Cdc42 are small G-proteins that regulate actin dynamics and affect plasma membrane protrusion and vesicle traffic. We used conditional mutagenesis in mice to demonstrate that Rac1 and Cdc42 are essential for myoblast fusion in vivo and in vitro. The deficit in fusion of Rac1 or Cdc42 mutant myoblasts correlates with a deficit in the recruitment of actin fibers and vinculin to myoblast contact sites. Comparison of the changes observed in mutant myogenic cells indicates that Rac1 and Cdc42 function in a nonredundant and not completely overlapping manner during the fusion process. Our genetic analysis demonstrates thus that the function of Rac in myoblast fusion is evolutionarily conserved from insects to mammals and that Cdc42, a molecule hitherto not implicated in myoblast fusion, is essential for the fusion of murine myoblasts.
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Department of Neuroscience, Robert-Rössle-Strasse 10, 13125 Berlin, Germany.
authors.forename: Elena
authors.initials: E
authors.lastname: Vasyutina
authors.forename: Benedetta
authors.initials: B
authors.lastname: Martarelli
authors.forename: Cord
authors.initials: C
authors.lastname: Brakebusch
authors.forename: Hagen
authors.initials: H
authors.lastname: Wende
authors.forename: Carmen
authors.initials: C
authors.lastname: Birchmeier
mesh_terms: D000818:Animals; D002459:Cell Fusion; D004330:Drosophila / Q000235:genetics; D019143:Evolution, Molecular; D051379:Mice; D008822:Mice, Transgenic; D016296:Mutagenesis; D032448:Myoblasts, Skeletal / Q000201:enzymology / Q000502:physiology*; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein