Two types of arrestins expressed in medaka rod photoreceptors

Similar to visual arrestins of other vertebrates, two subtypes of medaka vi sual arrestins, KfhArr-R1 and KfhArr-C, are selectively expressed in rods a nd cones, respectively [Hisatomi et al, (1997) FEES Lett, 411, 12-18]. We i solated a cDNA encoding the third arrestin, KfhArr-R2, from a medaka retina l cDNA library. Phylogenetic analysis of arrestin sequences suggests that K fhArr-R2 is classified into the rod arrestin subtype, In situ hybridization indicated that KfhArr-R2 mRNA is localized in most of the rod photorecepto rs, suggesting that both KfhArr-R1 and -R2 are co-expressed in rods. Antise ra against KfhArr-R2 recognized outer segments, but anti-KfhArr-R1 antisera reacted with cell bodies and synaptic termini in light-adapted rods. It se ems likely that KfhArr-R1 and -R2 play different roles in rod photoreceptor s. (C) 1999 Federation of European Biochemical Societies.