Figure 3
The echinus transcript is expressed at low, uniform levels in the pupal eye, and GAL4-driver-dependent expression of ec-SF1 or an ec-silencing microRNA suggests that pigment cells are an important site of ec action. (A,B) Tissue in situ hybridization of an echinus antisense probe complementary to all splice forms in 28 hr APF pupal retinas. (A) Focal plane showing primary pigment cells. (B) Focal plane showing IOCs. (C-E) Pupal retinas from heterozygous ecPlacZ/+ flies showing anti-β galactosidase staining in cone cells (C), primary pigment cells (D), and IOCs (E). Cell types indicated are cones (C), primaries (P), and IOCs (*). (F-F") 24 hr pupal retina from LL54-GAL4; UAS-GFP flies stained with anti-Dlg to outline cell boundaries (F, F") and GFP (F',F") to visualize the LL54-GAL4 expression pattern. (G-G") 29 hr pupal retinas from LL54-GAL4; UAS-GFP flies stained as above. LL54-GAL4 is expressed primarily, if not exclusively in pigment cells, but not bristles or cone cells. (H) 36 hr pupal eye from LL54-GAL4; UAS-CG2904-RNAi stained with anti-Dlg. Extra IOCs and sorting defects are apparent. Arrows indicate bristles.