Fig. 2. Expression patterns of Ser and a Ser wing enhancer in wing imaginal discs. (A-G) Wing imaginal discs. UAS-nuc-lacZ expression driven by the Ser wing enhancer construct 5 (Gal4) was visualized by ß-galactosidase antibody staining (A,C,D). These patterns are identical to those of the endogenous Ser protein (not shown). Ser mRNA was detected by in situ hybridization in developing wing discs (E-G). (A,B,E) Ser mRNA and construct 5 are expressed in dorsal cells in early third instar. (B) The expression patterns of construct 5 (Gal4)/UAS-GFP (green) and apterous-lacZ (red), are co-localized (yellow) in dorsal cells of wing and haltere discs. Dorsal is to the left for the haltere disc. White dashed circles outline the discs. (C,F) By the mid third instar, construct 5 (Gal4)/UAS-nuc-lacZ and Ser mRNA are preferentially expressed along the DV border. (D,G) At the end of the third instar, they are expressed in two stripes flanking the DV boundary, with higher expression dorsally. They are also expressed in presumptive veins (L3, L4 and L5). m, margin.