Conditional overexpression of ewg reduces synaptic growth. (a) Western blot of EWG in larval brains upon induced expression. EWG levels in larval brains were compared between elav-GS-GAL4 UAS-ewg animals fed with RU486 (1.2, 4.8 and 19.2 μg/10 ml food, lanes 3-5) and uninduced animals (lane 2), and to adult heads (lane 1). Note that a two-fold overexpression of EWG is effective to reduce synaptic growth (lane 3) compared to wild type (lane 2). (b,c) NMJs of control and EWG overexpressing animals. Shown are NMJs at muscle 13 of uninduced (b) or induced (c, 1.2 μg RU486/10 ml food) elav-GS-GAL4 UAS-ewg animals stained with anti-HRP antibodies. The scale bar in (b) is 20 μm. (d) Quantification of synaptic growth defects with excess EWG. Shown are means of bouton numbers (type 1b at muscle 13) with standard errors (n = 12-15) of uninduced (b) or induced (c, 1.2 μg RU486/10 ml food) elav-GS-GAL4 UAS-ewg animals. Statistically significant differences are indicated by asterisks (***p < 0.0001).