Fig. 8. Dynamic expression pattern of Aos in the wing imaginal disc. (A-B) Third instar aos-lacZ wing imaginal disc stained for ß-galactosidase expression (green) and Ubx (red; shown only in B). Aos is expressed in the presumptive veins and in the notum. Note that aos-lacZ and Ubx are not colocalized, suggesting that at this stage of development Aos is expressed only DP cells. Large cells in that notum that express Aos are probably adepithelial cells. (C) Third instar wild type wing disc stained for Ct expression. In the notum Ct is expressed in the myoblasts. (D and D') Part of the notum of aos-lacZ wing imaginal disc stained for ß-galactosidase expression (green) and Ct (red; shown only in D'). Note co-localization of Aos and Ct in the myoblasts. (E,F) Early second instar aos-lacZ wing imaginal discs stained for ß-galactosidase expression (green). Aos is expressed in large PM cells overlaying the notum as well as the pouch. Disc in E is also stained for Ct (red), which marks myoblasts. At this stage during development, myoblasts are localized to the anterior compartment, whereas Aos-expressing cells are in the posterior compartment. (G) Late second instar aos-lacZ wing imaginal disc. (H) Late second instar wild-type wing imaginal disc stained for Ubx expression. Note that Aos and Ubx share a similar expression pattern. (I-K) Late second instar aos-lacZ wing imaginal disc stained for both ß-galactosidase (green; I) and Ubx (red; J) expression. K is the merge of I and K. Note colocalization of Aos and Ubx in PM cells. (L) Early third instar aos-lacZ disc. Aos expression in the pouch (asterisk) begins at this stage during development.