Expression of NMIIA, F-actin, and pMLC in control and Myh9 deficient embryos. (A) Optical sections (planar and sagittal views) of confocal images from Myh9 cKO embryos and their control littermates stained with NMIIA (green) at hillock (E12.5) and bulb (E13.5) stages. Epithelium was stained with EpCAM (white) and nuclei with Hoechst (cyan). Dashed line marks the epithelial-mesenchymal border, and arrowheads mark the plane of optical section. Scale bar, 50 µm. (B–D) Optical sections (planar and sagittal views) of confocal images from Myh9 cKO and control littermate embryos stained with epithelial marker (EpCAM, white in the upper panel), F-actin (phalloidin, represented in LUT depicted in the middle panel), pMLC (represented in LUT depicted in the lower panel) at hillock (E12.5; B), bud (E13.0; C), and bulb (E13.5; D) stages. Scale bar, 50 µm. Dashed line marks the epithelial-mesenchymal border, and arrowheads mark the plane of the optical section. i and ii are close-ups of the regions indicated by orange boxes.