Figure 1. Occludin localization in polarized human retinal pigment epithelium (ARPE-19) cells. Occludin (green) and 4',6-diamidino-2-phenylindole (DAPI; blue) immunolocalization in ARPE-19 cells that were cultured for 4 weeks on Transwells to induce polarization reveals circumferential junctions and demonstrates a cuboidal monolayer. Scale bar is 50 μm.