We have been using a differential cDNA cloning approach to isolate human retina-specific and retina-enriched genes [1]. A 1,314 bp cDNA was isolated by this approach, representing a highly retina-specific message encoding a 388 amino acid protein showing 58%, 50%, and 49% homology to bovine β-arrestin, and bovine and human retinal arrestin (S-antigen), respectively. Chromosomal mapping localized this new arrestin genc to the proximal long arm of the X chromosome, hence it was named X-arrestin. In situ hybridization demonstrated its expression in the inner and outer segments and the inner plexiform regions of the retina.
