Translator Disclaimer
1 January 2007 A Third Photoreceptor-Specific GRK Found in the Retina of Oryzias latipes (Japanese killifish)
Author Affiliations +

We previously reported that the teleost fish medaka (Oryzias latipes, Japanese killifish), possesses two kinds of G protein-coupled receptor kinases (GRKs) in the retina with different localizations: GRK7 (OlGRK-C) in cones and GRK1 (OlGRK-R1) in rods. To further clarify the diversity of teleost photoreceptor GRKs, we sought other medaka GRKs. We found an additional cDNA that encodes a second retina-specific GRK1 (OlGRK-R2). In situ hybridization experiments demonstrated that OlGRK-R2 mRNA is selectively expressed in rods. Sequence analysis of the Fugu rubripes genomic database unveiled a larger diversity of GRKs than previously expected. We also describe the light-dependent regulation of GRK1, a phenomenon that has not been found in other species. Immunocytochemical analysis indicated that OlGRK-R2 is localized in rod outer segments, independent of light condition. OlGRK-R1 is localized in the rod inner segments and synaptic termini of dark-adapted eyes, and moves to rod outer segments after light adaptation. Our studies suggest that the two medaka GRKs are not functionally redundant, and demonstrate a complicated light-dependent regulation of GRK1 in vivo.

Yoshikazu Imanishi, Osamu Hisatomi, Shintaro Yamamoto, Takunori Satoh, Shuichi Kotaka, Yuko Kobayashi, and Fumio Tokunaga "A Third Photoreceptor-Specific GRK Found in the Retina of Oryzias latipes (Japanese killifish)," Zoological Science 24(1), 87-93, (1 January 2007).
Received: 19 January 2006; Accepted: 1 September 2006; Published: 1 January 2007

Get copyright permission
Back to Top