Involvement of growth factors and their receptors in morphogenesis of the chick limb

Vertebrate limb morphogenesis has been investigated as a model system of pattern formation. Recent results suggest that peptide growth factors are involved in the limb morphogenesis. Members of the fibroblast growth factor family stimulate proliferation of the limb mesenchymal cells, while members of the transforming growth factor (TGF)-β family, in contrast, inhibit the proliferation. The antagonistic effect between the two families is probably essential for establishment of both anteroposterior and proximodistal axes. The Wnt and TGF-β families may be related to morphogenesis of the dorsoventral axis. The three families are also involved in chondrogenesis, osteogenesis, and feather formation. In this review, possible roles of such growth factors and their receptors in morphogenesis of the limb are discussed.