Figure 5

R7 cell development in ttk^- mutant ommatidia is dependent upon Lz function. A. Projected confocal image of Runt labelled cells in a wild-type disc show one R8 cell per ommatidial cluster for approximately six rows posterior to the morphogenetic furrow (Mf; arrow). At row seven, Runt-expressing R7 cells are recruited to each ommatidium and Runt "doublets" are observed. B. In the ttk^1e11 mutant ommatidia, ectopic Runt positive R7 cells are observed. C. Only single R8 cells are observed in developing ommatidia of lz^mr1; ttk^1e11 ommatidia. B and C show discs where ttk^- clones occupied the majority of the eye disc (β-galactosidase not shown). B and C (insets) show mosaic images, where ectopic Runt positive cells can be observed in ttk^1e11 clonal patches (B inset; GFP negative clones outlined). C Inset. In lz^mr1 mutant discs, R7 cells are not recruited to the ommatidia, and the generation of ttk^1e11 clones in this background (outlined in inset) does not result in the recruitment of R7 precursor cells. Scale bars indicate 10 μm.