Fig. 4. Nab represses the transcriptional activity of Rn. (A-E) Leg, wing and a high magnification of the wing hinge area of wild-type (A), rn⁵/rn²⁰ (B), rnGal4/EP#13 (C), UASrn/+; rnGal4/EP#13 (D) and DllGal4/+; EP#13/+ (E) Drosophila. T1-5, tarsal segments. Arrows point to the sex combs at the distal end of the first tarsal segment (T1), and arrowheads point to the claw organs at the distal end of the leg. Note that the rn lack-of-function phenotypes (B) are identical to the nab misexpression phenotypes (C): tarsal segments (T2-T4) are lost or much reduced and the wing hinge is deleted. In D, the leg and wing phenotypes shown in C are partially rescued by overexpression of UASrn. Note that although nab is expressed in a broader domain in E than in C (from mid-tibia to the distal end of the leg) the phenotype is the same. (F,G) Wg antibody staining (red) in rnGal4/EP#13 (F) and UASrn/+; rnGal4 UASGFP/EP#13 (G) wing discs. Nab antibody staining is shown in blue and rn expression in green (GFP). Arrows, IR; arrowheads, OR. Note that in F, wg expression in the IR is lost. The simultaneous misexpression of Rn and Nab (G) partially rescues wg expression in the IR. In the right-hand panel, individual channels of a view in the z-axis are shown to indicate that in flies with this genotype, nab is co-expressed with wg in the IR.