Fig. 4. Overexpression of Drosophila Smad2 (Smox) can rescue the effects of overexpression of the Drosophila B subunit Twins in the wing. (A) Phenotypically wild-type wing from +/Y; UAS-tws23; UAS-Smox8D3 male. (B) Small, blistered wing from A9-GAL4; UAS-tws23; + male. All wings from these males are smaller than wild type; 80% were cupped and blistered with little or no evidence of veins. (C) Wing from A9-GAL4; +; UAS-Smox8D3 male. In this genotype, wing veins formed a delta at the margin, and additional wing vein material was often observed (arrows). (D) Phenotypically normal wing from A9-GAL4; UAS-tws23; UAS-Smox8D3 male. All veins terminated normally at the margin (arrows).