Fig. 6. Ectopic lola induces ectopic slit. The splice variant lola 4.7 was placed under control of UAS_G and expressed throughout the developing neuroectoderm by crossing to GAL4-112A (Fuerstenberg and Giniger, 1998). slit expression was then assayed by in situ hybridization (A,B) or antibody staining (C-F). Ventral (E,F) or sagittal (A-D) views of stage 17 embryos are shown. In wild-type stage 17 embryos (A,C,E), Slit is expressed only in midline glial cells; expression of lola 4.7 throughout the neuroectoderm causes ectopic expression of slit mRNA (B) and protein (D,F), but only in additional midline cells.