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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Body Patterning
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Cytoskeletal Proteins / genetics
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Cytoskeletal Proteins / metabolism*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Early Growth Response Protein 2
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Ectoderm / metabolism
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Embryo, Nonmammalian
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Female
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Gene Expression Regulation, Developmental
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Homeodomain Proteins*
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / metabolism
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Nervous System / embryology*
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Nervous System / metabolism
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Otx Transcription Factors
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Proteins / genetics
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Proteins / metabolism
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism*
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Signal Transduction*
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Trans-Activators / genetics
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Trans-Activators / metabolism
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Wnt Proteins
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Wnt3 Protein
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Xenopus / embryology*
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Xenopus / genetics
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Xenopus / metabolism
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Xenopus Proteins
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Zebrafish Proteins*
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beta Catenin
Substances
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CTNNB1 protein, Xenopus
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Cytoskeletal Proteins
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DNA-Binding Proteins
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Early Growth Response Protein 2
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Homeodomain Proteins
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Nerve Tissue Proteins
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Otx Transcription Factors
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Proteins
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Proto-Oncogene Proteins
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Trans-Activators
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Transcription Factors
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Wnt Proteins
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Wnt3 Protein
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Xenopus Proteins
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Zebrafish Proteins
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beta Catenin