Localization of transmembrane proteins in photoreceptors. A–F) WT and Rp2h knockout mouse retina frozen sections (age of 1 mo, A, B; and age 14 mo, C–F were stained with anti-M/L-opsin antibody [green]). The 14-mo-old retinas (C–F) were counterstained with DAPI (blue) to contrast the outer nuclear layer. G, H) Distribution of S-opsin in the retina of the Rp2h−/− mouse. Mouse retina frozen sections at the age of 1 mo were stained with anti–S-opsin (red). I–L) One-month-old retina sections stained with anti-rhodopsin (I, J), and anti-GC1 (K, L). Scale bar, 10 μm.