Fig. 5. Shroom3 is sufficient to drive apicobasal cell elongation in naïve epithelial cells. (A) Schematic depicting the epithelial character of the superficial blastomeres in Xenopus (see also Chalmers et al., 2005; Dollar et al., 2005; Haigo et al., 2003; Roberts et al., 1992). (B) Cross-section through superficial blastomeres of a control embryo. Phalloidin staining reveals cell cortices (green) and propidium iodide reveals nuclei (red). (C) Cross-section through superficial blastomeres of an embryo ectopically expressing Shroom3. Cells with accumulated apical actin also display increased cell height. (D) Graph of apicobasal cell height and the distance between the basal cell surface and the basal limit of the nucleus for superficial blastomeres in control and Shroom3-injected regions (mean ± s.e.m.; ctl, n=26; Shroom3, n=19).