Ectopic Runt and Prospero labelled R7 cells develop in ttk1e11 and ttkrm730 mutant ommatidia. A. Light micrographs of a wild-type (wt) eye and (B-C) ttk1e11 and ttkrm730 mutants show w- clonal tissue covering most of the eye. D-F. Projected confocal images of third instar eye discs labelled with Runt (Red) and β-galactosidase (β-gal; green). Arrow marks the morphogenetic furrow (Mf); posterior is towards the bottom. Absence of β-gal represents ttk1e11 (E) and ttkrm730 (F) clonal cells. In wt discs (D), one Runt labelled R8 cell (8) is observed in each ommatidia for six rows posterior to the Mf. At row seven, one R7 cell (7) is recruited. In both ttk1e11 (E) and ttkrm730 (F) discs, ectopic Runt positive R7 cells appear seven rows posterior to the Mf. G-I. Projected confocal images of Pros labelled cells (red) reveal an increase in Pros expression in ttk- clonal tissue (H-I) compared to wt tissue (G). Single planar images (G'-I") show the presence of one Pros positive cell in the R7 cell plane of wt eye discs (G'), while four Pros labelled cone cells (CCs) are present in a more apical plane (G"). In ttk1e11 and ttkrm730 ommatidia, more than one Pros labelled cell is often observed in the R7 cell plane (H', I'), and less than four Pros labelled CCs can be observed in the apical plane (H", I"). The boxed region in each panel represents one ommatidium. Scale Bars in D-I indicate 10 μm, in G'-I", 5 μm.
Siddall et al. BMC Developmental Biology 2009 9:64 doi:10.1186/1471-213X-9-64