Abstract
Animal cap explants from Xenopus embryos injected with a dominant negative Raf-1 mutant, termed NAF (not a functional Raf), demonstrated a complete block to basic fibroblast growth factor (FGF)-stimulated mesoderm induction. Activin induction of mesoderm was normal in embryos that expressed NAF. Injection of NAF RNA into 2-cell stage embryos blocked normal development during neurula stages and caused severe posterior truncations in tadpoles. The phenotype induced by NAF could be rescued by coinjection of wild-type raf-1 RNA. The NAF mutant functioned by specifically blocking the activation of endogenous Raf kinase activity. These findings suggest that Raf-1 mediates FGF, but not activin, receptor signaling during mesoderm induction and implicate Raf-1 as a key signaling molecule in the development of posterior structure.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Activins
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Amino Acid Sequence
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Animals
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Base Sequence
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Calcium / metabolism
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Embryo, Nonmammalian / cytology
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Embryo, Nonmammalian / physiology*
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Epitopes / analysis
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Female
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Fibroblast Growth Factor 2 / pharmacology*
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Gastrula / cytology
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Gastrula / drug effects
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Gastrula / physiology
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Immunohistochemistry
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Inhibins / pharmacology
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Mesoderm / cytology
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Mesoderm / drug effects
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Mesoderm / physiology*
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Molecular Sequence Data
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Mutagenesis, Site-Directed
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Oocytes / physiology*
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Protein Serine-Threonine Kinases / metabolism*
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism*
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Proto-Oncogene Proteins c-raf
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RNA / genetics
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RNA / isolation & purification
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Regulatory Sequences, Nucleic Acid
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Xenopus / embryology*
Substances
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Epitopes
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Proto-Oncogene Proteins
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Fibroblast Growth Factor 2
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Activins
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Inhibins
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RNA
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Protein Serine-Threonine Kinases
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Proto-Oncogene Proteins c-raf
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Calcium