Figure 7. Nub represses Stat92E activity and upd production.

(A) Hop-expressing clones (green) moderately repress Nub (red) (small red arrows in A′ and A″) but do not alter Tsh (blue) (green arrows in A‴). A′ is single channel for GFP; A″ for Nub; A‴ for Tsh.

(B) Nub-expressing clones (red) residing within the hinge autonomously (B′, arrow) repress 10xSTAT-GFP (green). B′ is single channel for 10xSTAT-GFP.

(C) 10xSTAT-GFP extends distally into the pouch in nub¹ mutant clones, which lack βGal (red). Nub is blue. B″ is single channel for 10xSTAT-GFP and the expansion into the pouch is indicated by the arrows.

(D, E) dome-gal4, UAS-GFP (labeled “dome” (green)) is observed only in the dorsal medial hinge (arrow in C′). dome-gal4, UAS-lacZ (marked by βGal (red) in mosaic nub¹ mutant clones (marked by the absence of GFP) is ectopically expressed in the pouch (E′, E″, arrows). Nub is blue. E′ is single channel for GFP; E″ for βGal.

(F) Clonal mis-expression of Stat92E^FL (green) together with Nub (red) does not restore expression of Zfh2 (blue) and hinge folds to the clone, suggesting that Nub represses Stat92E activity and not Stat92E expression. The clone is most easily visualized by ectopic Nub expression. F′ is single channel for Nub; F″ for Stat92E; F‴ for Zfh2.

(G) 10xSTAT-GFP expression domain (green) is separated from the Rn domain (red) by the Wg IR (blue). G′ shows merge of 10xSTAT-GFP and Rn channels. G″ is single channel for 10xSTAT-GFP; G‴ for Rn.

(H, I) Rn-expressing clones that are marked with βgal (red) residing within the hinge autonomously (H′, I′, arrows) repress 10xSTAT-GFP (green). H′ and I′ are single channels for 10xSTAT-GFP.

(J) 10xSTAT-GFP (green) is downregulated when Rn is mis-expressed by MS1096-Gal4. Nub is red and Tsh is blue. Arrows in J′ mark the perturbations to 10xSTAT-GFP in the dorsal hinge. J′ is single channel for 10xSTAT-GFP; J″ for Nub; J‴ for Tsh.

(K) upd-gal4, UAS-GFP (upd>GFP) is ectopically expressed in pouch cells in nub¹ mutant clones marked by the absence of Nub in red and βgal in blue. K′ is the single channel for upd>gfp with the clone boundary outlined by red line.

(L, M) in situ hybridization reveals the expression of upd within the medial hinge in a wild type second instar wing disc (L). In a dpp>nub second instar disc, upd is repressed within the dpp domain (arrow, M).

(N, O) MS1096-driven over-expression of upd (MS1096>upd) in the pouch and dorsal wing results in ectopic activation of the JAK/STAT pathway in the pouch (N′), and small wings in the adult (O).