Fig. 8. Expression of SMAD4^100T activates the expression of the WG target gene achaete. (A) Wild-type third instar wing disc stained for Achaete (AC). a, anterior; m, proximal margin; v, ventral surface; dis, distal margin. (B) zw3^M11 clones produce ectopic AC expression on the presumptive blade (arrowheads). (C) UAS.SMAD4^100T/C765.Gal4 with ectopic AC expression on the presumptive blade (arrowheads). (D) UAS.Dpp/C765.Gal4. This is a lethal genotype. The disc is overgrown (image shown at a reduced magnification) but it has wild-type AC expression. (E) UAS.Gbb/C765.Gal4 with reduced AC expression in the proximal anterior margin primordia (arrowhead).