title: A morphogen gradient of Wnt/beta-catenin signalling regulates anteroposterior neural patterning in Xenopus.
abstract: Anteroposterior (AP) patterning of the vertebrate neural plate is initiated during gastrulation and is regulated by Spemann's organizer and its derivatives. The prevailing model for AP patterning predicts a caudally increasing gradient of a 'transformer' which posteriorizes anteriorly specified neural cells. However, the molecular identity of the transforming gradient has remained elusive. We show that in Xenopus embryos (1) dose-dependent Wnt signalling is both necessary and sufficient for AP patterning of the neuraxis, (2) Wnt/beta-catenin signalling occurs in a direct and long-range fashion within the ectoderm, and (3) that there is an endogenous AP gradient of Wnt/beta-catenin signalling in the presumptive neural plate of the Xenopus gastrula. Our results indicate that an activity gradient of Wnt/beta-catenin signalling acts as transforming morphogen to pattern the Xenopus central nervous system.
authors.affiliation: Division of Molecular Embryology, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Kiecker
authors.forename: C
authors.initials: C
authors.lastname: Niehrs
mesh_terms: D000818:Animals; D019521:Body Patterning; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D051767:Early Growth Response Protein 2; D004475:Ectoderm / Q000378:metabolism; D004625:Embryo, Nonmammalian; D005260:Female; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009420:Nervous System / Q000196:embryology* / Q000378:metabolism; D051857:Otx Transcription Factors; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D051153:Wnt Proteins; D060508:Wnt3 Protein; D014981:Xenopus / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin
chemical_list: C495266:CTNNB1 protein, Xenopus; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D051767:Early Growth Response Protein 2; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D051857:Otx Transcription Factors; D011506:Proteins; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D051153:Wnt Proteins; D060508:Wnt3 Protein; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D051176:beta Catenin