Figure 3. Changing cell shape alters sub-apical MT organization.

(a) Representative images of dorsal–lateral epidermis, visualized as described in Fig. 1, of stage 14 wild type (left) and embryos with germband retraction blocked by the ush¹ mutant (centre) embryos, or inducing cell death in the amnioserosa using Gal4^332.3>reaper (right). Scale bars, 10 μm. (b) Quantification of cell eccentricity and cell's long/short axes ratio (left), MTSD (centre) and MTDEV (right) shows germband retraction is required for cell elongation and MT organization. Cells from 12 embryos (wild-type, ush¹ mutant) and 10 embryos (Gal4^332.3>reaper) from two independent experiments were analysed. Statistical analysis was performed with one-way ANOVA and Fisher's LSD post hoc analysis. *P<0.05, ****P<0.0001, NS, not significantly different. (c) Correlation between either MTSD (top) or MTDEV (bottom), and cell eccentricity is retained when cell elongation is blocked. Each dot represents the cells from a single embryo (mean±s.e.m.).