Fig. 4. sna is required for the physiological functions of Bsk.

Light micrographs of Drosophila adult wings a–d and fluorescence micrographs of third instar larval wing discs f–i and k–n are shown. RNAi-mediated down-regulation of puc along the A/P compartment boundary by ptc-GAL4 triggers the loss-of-ACV phenotype in adult wings a, which is resulted from cell death in larval wing discs f. Both phenotypes depend on endogenous Bsk c and h and Sna d and i. The bottom panels show high magnification views of the boxed areas in upper panels a–d. Knockdown of dlg along the A/P compartment boundary (ptc > dlg-IR) induces Bsk-dependent cell death k and m, which is significantly blocked by depletion of sna n. LacZ expression is used as a negative control b, g, and l. e, j, and o Statistical analysis of ACV phenotype (n = 20 for each genotype) and cell death in wing discs (n = 10) as shown in figures a–d, f–i, and k–n, respectively. 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. See the electronic supplementary material for detailed genotypes. Scale bars: 100 μm in a–d (upper panels), 50 μm in a–d (lower panels) and f–n.