Axis determination by inhibition of Wnt signaling in Xenopus.
The Wnt family of secreted polypeptides participate in a variety of developmental processes in which embryonic polarity is established. To study a role for Wnt ligands in vertebrate axis determination, we interfered with Wnt signaling in the embryo using the extracellular domain of Xenopus Frizzled 8 (ECD8), which blocks Wnt-dependent activation of a target gene in Xenopus ectodermal explants. Expression of ECD8 in ventral blastomeres resulted in formation of secondary axes containing abundant notochord and head structures. These results suggest that Wnt signaling is required to maintain ventral cell fates and has to be suppressed for dorsal development to occur.
Itoh
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Department of Microbiology and Molecular Genetics, Harvard Medical School and Molecular Medicine Unit, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215 USA.
Sokol
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D000818:Animals; D001757:Blastomeres / Q000502:physiology; D019521:Body Patterning; D003598:Cytoskeletal Proteins; D004475:Ectoderm / Q000502:physiology*; D004625:Embryo, Nonmammalian / Q000502:physiology*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006257:Head / Q000196:embryology; D008648:Mesoderm / Q000502:physiology; D009024:Morphogenesis; D009672:Notochord / Q000502:physiology; D009924:Organ Culture Techniques; D010063:Ovum / Q000502:physiology*; D011506:Proteins / Q000235:genetics*; D011956:Receptors, Cell Surface / Q000235:genetics*; D015398:Signal Transduction; D051153:Wnt Proteins; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000196:embryology*; D029961:Zebrafish Proteins
D003598:Cytoskeletal Proteins; C113865:FZD8 protein, Xenopus; D011506:Proteins; D011956:Receptors, Cell Surface; D051153:Wnt Proteins; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; C094521:wnt8a protein, zebrafish