Fig. 4

Expression of DRx enhancer-Gal4 strains in the embryo. A The genomic organization of the DRx locus is shown together with the location of fragments from the upstream and intronic regions of the DRx locus used to test enhancer activities in the respective Gal4 strains. B-J Dorsal views of the anterior parts of stage 15 Drosophila embryos. The anterior ends of the embryos are pointing downward. An anti-DRx antibody was used to visualize the nuclear DRx expression pattern in green, and enhancer-Gal4-driven UAS-H2B-mRFP1 expression was used to visualize the nuclear expression patterns generated by the various enhancers in red. The Gal4 strain numbers are indicated; yellow arrowheads indicate important regions showing coexpression of DRx and the fluorescence marker, and red arrowheads denote regions where only the enhancer expression is visible. Brain domains showing coexpression were labelled according to Fig. 1. For symmetrical expression domains arrowheads are only shown for the right side. Abbreviations: CL, clypeolabrum; DAL, dorsal anterior lateral; DAM, dorsal anterior medial; DPLc, dorsal central lateral; DPM, dorsal posterior medial; MB, mushroom body. (Scale bars: 25 μm)