IMMUNOCYTOCHEMICAL LOCALIZATION OF RETINOID-BINDING PROTEIN IN THE DOGFISH RETINA

Purpose. The cellular localization of retinoid-binding proteins has be en extensively studied in the mammalian retina. Less is known about th e distribution and identity of retinoid-binding proteins in lower vert ebrate retinas. To understand their cellular functions, we have examin ed the distribution of specific retinoid-binding proteins in the neura l retina and RPE of an elasmobranch, the dogfish. Methods. Retinoid-bi nding proteins were localized in cryostat sections of dogfish eyes by the indirect immunofluorescence technique. We used well-characterized antibodies that have been previously employed for immunostaining. Immu noblotting was carried out to identify the antigen. Results. The studi es show that the cellular retinaldehyde-binding protein is present in the RPE and retinal Muller cells, and the interphotoreceptor retinoid- binding protein is found in the interstitial space between pigment epi thelium and retina. Conclusions. The distribution of retinoid-binding proteins in dogfish retina is similar to that found in the mammalian r etina which suggests that the sites of action of the retinoid-binding proteins are highly conserved in vertebrates.