title: Xbra functions as a switch between cell migration and convergent extension in the Xenopus gastrula.
abstract: During Xenopus gastrulation, the dorsal mesoderm exhibits two different cell behaviors in two different regions: active cell migration of prechordal mesoderm and convergent extension of chordamesoderm. Although many genes involved in specification and differentiation of the dorsal mesoderm have been studied, the role of these genes in controlling cell behaviors is poorly understood. To understand better the link between the development and cell behaviors of the dorsal mesoderm, we have examined these behaviors in dissociated cells and explants, where activin protein can induce both active cell migration and convergent extension. We find that Xbra, a transcription factor necessary for convergent extension, actively inhibits cell migration, both in animal cap explant assays and in the endogenous dorsal mesoderm. In addition, Xbra appears to inhibit cell migration by inhibiting adhesion to fibronectin. We propose that Xbra functions as a switch to keep cell migration and convergent extension as mutually exclusive behaviors during gastrulation.
authors.affiliation: Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Kwan
authors.forename: Marc W
authors.initials: MW
authors.lastname: Kirschner
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002465:Cell Movement / Q000502:physiology*; D000072261:Dishevelled Proteins; D005353:Fibronectins / Q000378:metabolism*; D005775:Gastrula / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism; D008648:Mesoderm / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011107:Polylysine / Q000378:metabolism; D020825:T-Box Domain Proteins / Q000378:metabolism*; D051153:Wnt Proteins; D014981:Xenopus; D029867:Xenopus Proteins; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D020744:rac GTP-Binding Proteins / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000072261:Dishevelled Proteins; D005353:Fibronectins; D006023:Glycoproteins; D010750:Phosphoproteins; D020825:T-Box Domain Proteins; C116765:TBXT protein, Xenopus; C103966:VegT protein, Xenopus; D051153:Wnt Proteins; D029867:Xenopus Proteins; C512785:wnt11b protein, Xenopus; D011107:Polylysine; D020764:cdc42 GTP-Binding Protein; D020744:rac GTP-Binding Proteins