Figure 7. ZO-1 expression in the RPE of the WT and p27 KO retinas after photoreceptor damage. A: ZO-1 immunolabeling is detected in the apical junctions of the RPE (arrows) and the outer limiting membrane (OLM, arrowheads). In the knockout (KO) retinas, the ZO-1-labeled OLM is disrupted where the RPE protrusions invade into the ONL (asterisks). Note attenuated ZO-1 labeling in the wild-type (WT) RPE after photoreceptor damage. DIC, differential interference contrast; Cont, control; ONL, outer nuclear layer. Scale bar = 20 μm. B: ZO-1 immunolabeling in whole mount RPE preparations, showing the significantly irregular size and shape of mutant RPE cells at day 3 after N-methyl-N-nitrosourea (MNU) treatment. Scale bar = 20 μm.