Figure 4. Dorsal to ventral transformations resulting from the loss of btd and Sp1.

(A) A T2 adult segment comprised mostly of Df(btd,Sp1) y tissue. These animals are generated via the genotype shown in Figure 3A. Dorsal is up. The normal notum, wing, and hinge are at the top; the bottom half of the tissue shows a transformation of ventral fates towards dorsal fates, including an ectopic wing, hinge, and notum (indicated by asterisks). Note that the normal notum, wing, and hinge are mutant (marked by y) but appear wild type. (B) Third instar leg imaginal disc of the same genotype as in (A) stained for GFP (absence marks the mutant tissue), Vg (red) and Eygone (Eyg; blue), which are markers for wing and notum fates, respectively. (C,D) Ectopic expression of Sp1^L (C) or mouse Sp8 (D), under the control of dpp-Gal4 result in the transformation of wing towards leg in the adult. Arrows indicate leg tissue. Remaining notum (N) and wing (W) tissue are indicated. Insets show a high magnification of the leg tissue, with bracts (small arrows). Note the appearance of leg structures also in the pronotum in (E) (arrowhead). (E,F) Ectopic expression of Sp1^L (E) or mouse Sp8 (F), under the control of dpp-Gal4 results in the induction of leg fates in the wing imaginal disc. These discs were stained for dpp-Gal4 expression (green), Dll (red), Dac (blue), or Vg (E, right-most panel). dpp>Sp8 also results in dramatic overgrowths that are not observed in the dpp>Sp1^L wing discs.