Abstract
Cranial neural crest cells generate the distinctive bone and connective tissues in the vertebrate head. Classical models of craniofacial development argue that the neural crest is prepatterned or preprogrammed to make specific head structures before its migration from the neural tube. In contrast, recent studies in several vertebrates have provided evidence for plasticity in patterning neural crest populations. Using tissue transposition and molecular analyses in avian embryos, we reconcile these findings by demonstrating that classical manipulation experiments, which form the basis of the prepatterning model, involved transplantation of a local signaling center, the isthmic organizer. FGF8 signaling from the isthmus alters Hoxa2 expression and consequently branchial arch patterning, demonstrating that neural crest cells are patterned by environmental signals.
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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Brain / cytology
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Brain / embryology*
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Brain / metabolism
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Brain Tissue Transplantation
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Branchial Region / embryology*
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Branchial Region / metabolism
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Cartilage / embryology
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Cell Movement
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Central Nervous System / embryology
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Chick Embryo
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Culture Techniques
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Fibroblast Growth Factor 8
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Fibroblast Growth Factors / pharmacology
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Fibroblast Growth Factors / physiology*
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Gene Expression Regulation, Developmental
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Homeodomain Proteins / genetics
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Homeodomain Proteins / metabolism
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Mesencephalon / embryology
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Mesencephalon / metabolism
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Morphogenesis
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Neural Crest / cytology
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Neural Crest / embryology*
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Neural Crest / metabolism
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Neural Crest / physiology
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Phenotype
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Rhombencephalon / embryology
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Rhombencephalon / metabolism
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Signal Transduction
Substances
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Homeodomain Proteins
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Fibroblast Growth Factor 8
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Fibroblast Growth Factors