FIGURE 7.

Par-1b is Required for the Morphogenesis and Differentiation of Myoepithelial Cells in the Developing Mouse SMG. (A) ICC was performed on E13 glands grown in culture for 96 hours that were treated with either NT siRNA or Par-1b siRNA (500nM) to detect Par-1b (cyan), ECAD (green), and SM α-actin (red), with DAPI staining (blue). The lower panel of images are zooms from boxed area in the top panel. A significant decrease in the number of SM α−actin-positive cells was observed following Par-1b siRNA treatment as well as an increase in ECAD⁺/SM α−actin⁺ cell height. Scale bars, 10µm top panels, 2µm bottom panels. (B) Western analysis was performed on whole glands following 96-hour culture with Par-1b or NT siRNA to detect the same proteins relative to GAPDH. Representative Westerns are shown. n ≥ 3 experiments for each blot. (C) Par-1b siRNA-induced knockdown was confirmed. (D) Par-1b siRNA treatment led to a reduction in the levels of SM α-actin relative to NT siRNA. (E) The height (µm) of individual epithelial cells expressing SM α-actin were measured in glands treated with NT siRNA or Par-1b siRNA for 96 hours. The height of the ECAD⁺/SM α-actin⁺ Par-1b siRNA-treated cells was significantly greater than that of ECAD⁺/SM α-actin⁺ NT siRNA-treated cells (n ≥ 25 cells/condition). (** p ≤ 0.01).