Fig. 3. Defects in IrreC-rst distribution in pupal eyes discs overexpressing crb_intra or mutant for irreC-rst. (A-C,J) Wild-type; (D-F,K) irreC^CT; (G-I,L) GMR-Gal4>UAS-crb_intra. (A-C) At 21% p.d., after completion of cell sorting, the IOCs form a single layer of lattice cells between the ommatidia. DE-cadherin (green) marks the apical regions of all cells. By contrast, IrreC-rst (violet) accumulates almost exclusively at the borders between primary pigment cells and IOCs (1°/IOC), where it colocalises with DE-cadherin (C). (D-F) In an irreC-rst^CT retina at 18% p.d., staining of IrreC-rst protein at the apical membranes of the 1°/IOC cell border is discontinuous. The protein localises in small patches along the membrane of the IOCs. The ommatidial clusters are surrounded by two or three rows of IOCs, outlined by staining for DE-cadherin. The distribution of DE-cadherin is unaffected by the mislocalisation of IrreC-rst (violet) and the protein still appears at the apex of all cells (green). (G-I) In a retina overexpressing Crb_intra at 22% p.d., DE-cadherin (green) and IrreC-rst (purple) are discontinuously scattered in the apical cell membranes where they mostly colocalise. In addition, IrreC-rst also is also found diffusely distributed and in vesicles in the cytoplasm. (J,K) Crb_intra-overexpressing pupal retina at 42% p.d. (L), after the phase of cell death. The distribution of IrreC-rst now resembles the wild-type pattern (compare L with J). IrreC-rst accumulates, as in wild-type (42% p.d.), at the 1°/IOC border and around the bristles. In an irreC-rst^CT retina at 40% p.d. (K) there is no continuous zone of IrreC-rst protein at the apical membranes that form the 1°/IOC border. Instead, the protein is localised in vesicles in the cytoplasm.