Fig. 4. Consequences of asymmetric dally expression in the wing. All wing discs in this figure were stained and imaged together and can therefore be directly compared. (A-A'') Control ci>GFP wing disc stained for GFP, P-Mad and Nubbin (Nub, a marker for the appendage-forming region of the disc). The white and red arrows indicate expression of P-Mad in the anterior and posterior compartments, respectively. (B,B') When UAS-dallyRNAi is expressed with en-Gal4, the extent of P-Mad staining in the P compartment (red arrow) is reduced as compared with control wing discs (A'). (C) Driving UAS-dallyRNAi in the P compartment reduces the P:A ratio (0.65 compared with 1.04 in control discs). (D,E) Driving UAS-dallyRNAi with en-Gal4 decreases the overall size of the adult wing by 19% as compared with control (en-Gal4; UAS-GFP) wings. The decreased P:A ratio is evident in the posterior shift of vein L4 of en>dallyRNAi wings (magenta arrowhead) compared with control wings (black arrowhead). (F,F') Driving UAS-dallyRNAi in the A compartment with ci-Gal4 increases the extent of P-Mad staining in the P compartment (red arrow) compared with control wing discs (A'). The levels of P-Mad staining in the AP organizers of these discs is increased compared with control wing discs (A'; see main text). (G) Driving UAS-dallyRNAi in the A compartment increases the P:A ratio (1.36 compared with 0.94 in control discs). (H,I) Although the increased P:A ratio is evident in the anterior shifting of vein L4 (H, arrowheads), the overall size of ci-Gal4 UAS UAS-dallyRNAi wings is the same as in control wings (I). A, anterior compartment; P, posterior compartment.