Fig. 4.

Sage and Fkh together are sufficient to drive high-level expression of SG genes. (A) Sage target gene expression in embryos expressing UAS-Sage or UAS-Fkh or both under control of en-Gal4. Black arrows indicate ectopic hindgut expression when UAS-Sage is expressed. White arrows indicate ectopic expression in the salivary duct with expression of UAS-Fkh. (B) Hindgut (HG) and Malpighian tubule (MT) staining of WT and tub-Gal4::UAS-Sage embryos. The white staining in the lower right panel indicates expression of all three markers in Malpighian tubules. (C) Global expression of both Sage and Fkh drives ectopic high-level expression of the SG marker protein SG1 in all ventral cells in early embryos but persistent high-level expression in late embryos occurs only in PS2 and in lateral regions of PS3, cells that also express Scr and its co-factors.