title: Cytochalasin B inhibits morphogenetic movement and muscle differentiation of activin-treated ectoderm in Xenopus.
abstract: Xenopus ectodermal explants (animal caps) begin to elongate after treatment with the mesoderm inducing factor activin A. This phenomenon mimics the convergent extension of dorsal mesoderm during gastrulation. To analyze the relationship between elongation movement and muscle differentiation, animal caps were treated with colchicine, taxol, cytochalasin B and hydroxyurea (HUA)/aphidicolin following activin treatment. Cytochalasin B disrupted the organization of actin filaments and inhibited the elongation of the activin-treated explants. Muscle differentiation was also inhibited in these explants at the histologic and molecular levels. Colchicine and taxol, which are known to affect microtubule organization, had little effect on elongation of the activin-treated exp ants. Co-treatment with HUA and aphidicolin caused serious damage on the explants and they did not undergo elongation. These results suggest that actin filaments play an important role in the elongation movement that leads to muscle differentiation of activin-treated explants.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tamai
authors.forename: C
authors.initials: C
authors.lastname: Yokota
authors.forename: T
authors.initials: T
authors.lastname: Ariizumi
authors.forename: M
authors.initials: M
authors.lastname: Asashima
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects; D028341:Activins; D000818:Animals; D016590:Aphidicolin / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects*; D003078:Colchicine / Q000494:pharmacology; D046508:Culture Techniques; D003571:Cytochalasin B / Q000494:pharmacology*; D004475:Ectoderm / Q000187:drug effects*; D004625:Embryo, Nonmammalian / Q000601:surgery; D004627:Embryonic Induction; D015870:Gene Expression; D006918:Hydroxyurea / Q000494:pharmacology; D007265:Inhibins / Q000494:pharmacology*; D009024:Morphogenesis / Q000187:drug effects; D009132:Muscles / Q000196:embryology*; D017239:Paclitaxel / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014981:Xenopus / Q000196:embryology*
chemical_list: D028341:Activins; D016590:Aphidicolin; D003571:Cytochalasin B; D007265:Inhibins; D017239:Paclitaxel; D003078:Colchicine; D006918:Hydroxyurea