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.
Jiang
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TX
Department of Pathology, University of Southern California, School of Medicine, Los Angeles 90033.
Chuong
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CM
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