Ripply3 is required for the maintenance of epithelial sheets in the morphogenesis of pharyngeal pouches

In this study, we found that the expression of mouse Ripply3 was specifically activated in accordance with the bending of the endodermal epithelium during the pouch formation. In Ripply3‐deficient embryos, a continuous monolayer of the endodermal epithelium was not maintained posterior to the 2nd pharyngeal pouch. Corresponding to the endodermal region of the deformed epithelium, the activated form of Integrin β1, which was localized at the basal side of the epithelial cells in the wild‐type embryos, was not persistently observed in the mutants. On the other hand, cell proliferation and apoptotic cell death in the endoderm were not obviously affected by the Ripply3 deficiency. Significantly, Ripply3 expressed in cultured cells was found to be preferentially accumulated in the focal adhesions, which are Integrin‐mediated adhesive contact sites transmitting mechanical force between the extracellular matrix and attached cells. Furthermore, Ripply3 promoted the maturation of focal adhesions in these cells. Thus, Ripply3 appears to have been activated to enhance the connection between the extracellular matrix and endodermal epithelial cells, as a mechanism to resist the mechanical stress generated during the bending of the epithelial sheets.

In the development of the pharyngeal pouches, Ripply3 is specifically expressed in bending endoderm, and required for the maintenance of a continuous monolayer epithelium in the bending. In vivo and in vitro evidence suggested that Rip...

Source: Development, Growth and Differentiation - January 1, 2018 Category: Research Authors: Yoshihiro Tsuchiya, Yusuke Mii, Kazunori Okada, Mikio Furuse, Tadashi Okubo, Shinji Takada Tags: ORIGINAL ARTICLE Source Type: research