(A) Schematic of the drug-selectable driver-response vector pairs for either the GAL4/UAS or the LexA/LexAOp binary expression systems. Driver vectors consist of a FlyLight library genomic enhancer element regulating GAL4 or LexA transcription factor expression, a G418 resistance maker, and a visual eye marker. Response vectors contain a 5xUAS or a 12xLexAOp driver binding DNA motif upstream of a fluorescent protein (mCherry or sfGFP), a blasticidin resistance marker, and visual eye marker. Transgenics were generated via co-injections of driver-response vector pairs into a double-docking site fly line using ΦC31 integrase.
(B–D) Results were visualized via immunofluorescent staining for the respective fluorescent proteins.
(B) Staining for R76H03::GAL4-driven mCherry in the central complex of the adult fly brain showed expression in the ellipsoid body (dotted circle) and innervating R4 cells (arrow; B′), although in the ventral nerve cord, staining revealed an X-shaped pattern similar to FlyLight data (B″).
(C) Staining for GFP in R20A02::GAL4; UAS-GFP adult fly brains labels the ellipsoid body (dashed circle) and R4 cells (arrow) in the brain, similar to previously reported expression of this enhancer (C′). Expression in the ventral nerve cord (VNC) shows less similarity to the previously reported pattern (C″).
(D) Staining for R70B04::LexA-driven sfGFP showed only very faint expression in the ellipsoid body within the central complex compared to the described enhancer expression from FlyLight (D′), although in the VNC, expression was very similar to FlyLight expression for this enhancer (D″). Staining for Disc Large (DLG) was used as a counterstain.
Scale bars represent 50 μm. See also Figure S7.