Distributions of Actin, Vinculin and Fibronectin in the Duodenum of Developing Chick Embryos: Immunohistochemical Studies at the Light Microscope Level

Abstract

Microscopic studies were made on the localizations of three different cytoskeletal proteins, actin, vinculin and fibronectin, in the duodenum of developing chick embryos and chicks by an indirect immuno-fluorescent staining method with specific antibodies. Topographical changes in the distributions of these three proteins seemed to be related to stages in morphogenesis of the duodenum. In early stages of embryonic development, findings suggested interaction between actin and vinculin in the apical region of epithelial cells and between actin and fibronectin in the basal region of these cells. From this stage, vinculin and fibronectin seemed to be of importance in determination and continuity of the polarity of the duodenal epithelium, and in control of the intracellular arrangement of actin. This relation between actin and vinculin seemed to continue throughout embryogenesis. The main role of actin in epithelial cells seemed to change on day 12 from that of forming constricting bundles for morphogenesis of previous ridges to that of microfilaments in the microvilli and the terminal web.