Fig. 1. Shrm is localized to the apical junctional complex (AJC). (A) Cryosections from e9.25 embryos were stained to detect Shrm (green) and ß-catenin (red). Shrm is distributed in an apically positioned honeycomb array in a projection of confocal sections. ap, apical. (B) An enlarged single optical section from the boxed region in panel A. Arrows indicate laterally positioned ß-catenin (red) and white arrowheads indicate apically positioned Shrm (green). (C) Cryosections from the truck region of an e9.5 embryo stained to detect Shrm (green, C'), ß-catenin (red) and F-actin (blue, C''). White arrowheads indicate apically positioned Shrm and F-actin. (D) Cryosections of e9.5 mouse embryos stained to detect Shrm (green) and Nectin-3 (red). A projected image shows Shrm (green) and Nectin-3 (red) in a honeycomb array. A single optical section demonstrating the overlapping distribution of Shrm and Nectin-3 in the putative AJC (white arrowhead) is shown in D'. (E) Equal amounts (30 µg) of total cell lysate from induced and un-induced ShrmL cells were assayed by western blot analysis using anti-Shrm sera. Filters were re-probed to detect ß-catenin to verify equal protein loading. (F and G) ShrmL cells were grown on Transwell filters for 48 hours in the presence (F) or absence (G) of doxycyclin and stained to detect Shrm (green) and ZO-1 (red). Top panels are X-Y projections and bottom panels are X-Z projections. Arrows indicate cells with rounded and polyhedral morphology. (H,I) ShrmL cells plated on Transwell filters were grown in the presence (H) or absence (I) of doxycyclin for 48 hours and stained to detect E-cadherin. Top panels are projections in the X-Y dimension and bottom panels are X-Z projections. Panels I' and I'' show individual optical sections of E-cadherin staining at the level of the basal surface and the AJC, respectively. Asterisks, constricted cells; dots, stretched cells. In all panels, scale bar is 15 µm, open arrowheads indicate the position at which X-Z projections were generated; ap, apical.