Fig. 2. Depletion of sna suppresses Egr-triggered cell death in development.

a–e Fluorescence micrographs of third instar larval eye discs are shown. Compared with the controls a, GMR > Egr-induced cell death in eye discs b remains unaffected by expression of a GFP RNAi c, but is dramatically impeded by knocking down sna d and e. f Statistical analysis of cell death in eye discs (n = 10) shown in figures a–e. Light micrographs of Drosophila adult wings g–k and fluorescence micrographs of third instar larval wing discs m–q are shown. Compared with the controls g and m, ectopic expression of Egr driven by ptc-GAL4 generates a loss-of-ACV phenotype in adults h and cell death in larval wing discs n, which are strongly blocked by RNAi-mediated depletion of sna j, k, p and q, but not that of GFP i and o. The lower panels show high magnification view of the boxed areas in upper panels g–k. Statistical analysis of the ACV phenotype in figures g–k (l, n = 20 for each genotype) and cell death in wing discs in figures m–q (r, n = 10) are shown. Error bars indicates standard deviation. One-way ANOVA with Bonferroni multiple comparison test was used to compute P-values, ***P < 0.001; ns, no significant difference. In all wings, anterior is to the left and distal up. UAS-GFP-IR is included c, i, o as a negative control to demonstrate that the suppressive effect of UAS-sna-IR is specific, but not a result of GAL4 titration by another UAS line. See the electronic supplementary material for detailed genotypes. Scale bars: 50 μm in a–e, g–k (lower panels) and m–q, 100 μm in g–k (upper panels).