Figure 8

Sina and Msi function as negative regulators of Ttk in R1/6/7 cells in early eye development. A. Image of a lz^Gal4, UAS-gfp disc stained with Bar (red) and GFP (green) B. In sina²/sina³ mutants, R1/R6 cells develop (yellow arrowhead) and express lz-driven GFP (green). Occasionally, mutant ommatidia with only one Bar labelled cell can be observed (white arrowhead). C. In lz^Gal4, UAS-GFP; sina²msi¹/sina³msi¹ discs, Bar positive cells are lost and GFP expression is reduced. D. Knockdown of Ttk in a sina²msi¹/sina³msi¹ mutant background by RNAi results in rescue of R1/R6 cells (yellow arrowhead). Occasionally, only one Bar positive cell is observed in the ommatidium of lz^Gal4, UAS-GFP; UAS-ttk^RNAi;sina²msi¹/sina³msi¹ discs (white arrowhead). E. Image of Runt labelled R7/R8 cells (grayscale) in a lz^Gal4, UAS-GFP disc (GFP not shown). The yellow box shows a "doublet" of R7/R8 cells in one ommatidium. E'. A higher magnification of Runt labelled R7 cells (red) expressing GFP (green). F-G. R7 cells are not observed in lz^Gal4, UAS-GFP;sina²/sina³ eye discs (F-F'), or in lz^Gal4, UAS-GFP;sina²msi¹/sina³msi¹ discs (G-G'). H-H'. In lz^Gal4, UAS-GFP; UAS-ttk^RNAi;sina²msi¹/sina³msi¹ eye discs, ectopic R7 cells from approximately row 7 posterior to the furrow are observed (yellow box) (H), and these cells (red) express GFP (green; H'). The asterix shows two R7 cells in the same confocal plane. The inset shows GFP in grayscale. Scale Bars in A-H indicate 10 μm, in E'-H', 5 μm.