Abstract
We have manipulated the chick limb bud by dorsoventrally inverting the ectoderm, by grafting the AER to the dorsal or ventral ectoderm and by insertion of an FGF-4 soaked heparin bead into the mesoderm. After dorso-ventral reversal of the ectoderm, Wnt-7a expression is autonomous from an early stage of limb development in the original dorsal ectoderm. Exogenous FGF-4 causes ectopic Wnt-7a expression and induces ectopic Shh. In addition, exogenous FGF-4 increases the thickness of cartilages and also shortens them, and both Bmp-2 and Bmp-4 may mediate this effect. The ectoderm outside the AER can regulate not only the dorso-ventral polarity of the underlying mesenchyme cells but also the cartilage formation, and both Bmp-2 and Bmp-4 may mediate this control.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Avian Proteins*
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Body Patterning / drug effects
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Bone Morphogenetic Protein 2
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Bone Morphogenetic Protein 4
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Bone Morphogenetic Proteins / genetics*
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Cartilage / drug effects
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Cartilage / embryology
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Chick Embryo
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Ectoderm / drug effects
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Ectoderm / metabolism
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Fibroblast Growth Factor 4
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Fibroblast Growth Factors / pharmacology*
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Gene Expression Regulation, Developmental / drug effects
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Hedgehog Proteins
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In Situ Hybridization
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Limb Buds / drug effects
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Limb Buds / embryology*
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Limb Buds / metabolism*
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Limb Buds / surgery
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Proteins / genetics*
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Proto-Oncogene Proteins / genetics*
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Proto-Oncogene Proteins / pharmacology*
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Time Factors
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Trans-Activators*
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Transforming Growth Factor beta*
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Wnt Proteins
Substances
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Avian Proteins
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Bone Morphogenetic Protein 2
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Bone Morphogenetic Protein 4
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Bone Morphogenetic Proteins
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Fibroblast Growth Factor 4
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Hedgehog Proteins
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Proteins
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Proto-Oncogene Proteins
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Trans-Activators
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Transforming Growth Factor beta
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WNT7A protein, Gallus gallus
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Wnt Proteins
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Fibroblast Growth Factors