Figure 2. Localization of GPR109A protein in intact retina. A: A hematoxylin and eosin-stained retinal cryosections is provided for comparison to panel B of the figure. B: Incubation of mouse retinal cryosections with anti- GPR109A antibody revealed positive (red) labeling for GPR109A protein exclusively in retinal pigment epithelium (RPE). Higher magnification of cryosections reveals that the GPR109A protein is associated specifically with RPE basolateral membrane (panel B, inset). Hoechst 33342 nuclear stain is shown in blue. In the inset, Nu means nucleus. C: No labeling was detected in retinal cryosections incubated with primary GPR109A antibody neutralized by incubation with excess antigenic peptide.