Mechanism of skin morphogenesis. I. Analyses with antibodies to adhesion molecules tenascin, N-CAM, and integrin.
To understand cell interactions during induction of skin appendages, we studied the roles of adhesion molecules N-CAM, tenascin, integrin, and fibronectin during feather development. Tenascin appeared in a periodic pattern on epithelia and was so far the earliest molecule detected in placodes. Three placode domains were identified: the anterior was positive for tenascin, the distal positive for N-CAM, and the posterior lacking both. Integrin appeared in dermal-epidermal junctions of placodes. In feather buds, sagittal sections revealed a transient anterior-posterior asymmetry with tenascin and N-CAM enriched in the anterior mesoderm. Tangential sections revealed a lateral-medial asymmetry with tenascin distributed in a ring shape and N-CAM in an "X" shape. Integrin was diffusely distributed within buds. Later tenascin and N-CAM were enriched in dermal papilla, the inducer of skin appendages. Perturbation of embryonic skin explant cultures with antibodies showed that anti-integrin beta 1 and anti-fibronectin blocked epithelial-mesenchymal interaction, anti-N-CAM caused uneven segregation of mesenchymal condensation, and anti-tenascin inhibited feather bud elongation. Dose-response curves showed gradual effects by these antibodies. The results indicated that these adhesion molecules are independently regulated and each contributes in different phases during morphogenesis of skin appendages.
Department of Pathology, University of Southern California, School of Medicine, Los Angeles 90033.
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D000818:Animals; D000906:Antibodies; D015816:Cell Adhesion Molecules, Neuronal / Q000032:analysis*; D002454:Cell Differentiation; D002455:Cell Division; D002642:Chick Embryo; D016326:Extracellular Matrix Proteins / Q000032:analysis*; D005241:Feathers / Q000196:embryology* / Q000648:ultrastructure; D016023:Integrins / Q000032:analysis*; D009024:Morphogenesis; D009924:Organ Culture Techniques; D012867:Skin / Q000196:embryology* / Q000648:ultrastructure; D019063:Tenascin
D000906:Antibodies; D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D016023:Integrins; D019063:Tenascin