title: Regulation of neural induction by the Chd and Bmp-4 antagonistic patterning signals in Xenopus.
abstract: In Drosophila the amount of neurogenic ectoderm, from which the central nervous system (CNS) derives, is regulated by a dorsal-ventral system of positional information in which two secreted molecules of antagonistic functions, decapentaplegic (dpp) and short-gastrulation (sog), play fundamental roles. The vertebrate homologue of dpp is either bmp-4 or bmp-2 (ref. 5), and the homologue os sog is chd (s-chordin). In Xenopus the CNS is induced by signals emanating from the organizer, and two proteins secreted by the organizer, noggin and follistatin, have been shown to induce neural tissue in animal-cap assays. Here we report that Chd, another organizer-specific secreted factor, has neuralizing activity and that this activity can be antagonized by Bmp-4. Inhibition of the function of the endogenous Bmp-4 present in the animal cap also leads to neural differentiation. We suggest that conserved molecular mechanisms involving chd/sog and bmp-4/dpp gene products pattern the ectoderm in Xenopus and in Drosophila.
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles 90095-1737, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Sasai
authors.forename: B
authors.initials: B
authors.lastname: Lu
authors.forename: H
authors.initials: H
authors.lastname: Steinbeisser
authors.forename: E M
authors.initials: EM
authors.lastname: De Robertis
mesh_terms: D000818:Animals; D001483:Base Sequence; D019485:Bone Morphogenetic Proteins; D046508:Culture Techniques; D017931:DNA Primers; D004330:Drosophila; D004627:Embryonic Induction; D005775:Gastrula / Q000166:cytology / Q000502:physiology; D006023:Glycoproteins; D006133:Growth Substances / Q000235:genetics / Q000502:physiology*; D036341:Intercellular Signaling Peptides and Proteins; D008648:Mesoderm / Q000502:physiology; D008969:Molecular Sequence Data; D009474:Neurons / Q000502:physiology*; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction; D014981:Xenopus
chemical_list: D019485:Bone Morphogenetic Proteins; D017931:DNA Primers; D006023:Glycoproteins; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; C054234:chordin