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Distribution and Translocation of Photoreceptor Gβγ‐phosducin System in Medaka Retina ‡
Author(s) -
Yamamoto Shintaro,
Hisatomi Osamu,
Hasegawa Akiyuki,
Kobayashi Yuko,
Tokunaga Fumio
Publication year - 2007
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/2006-03-03-ra-834
Subject(s) - visual phototransduction , retina , western blot , rhodopsin , biology , microbiology and biotechnology , biophysics , chemistry , anatomy , retinal , gene , biochemistry , neuroscience
Unlike other vertebrates, teleosts have rod‐ and cone‐specific phosducins (PD‐R and PD‐C) in the retina. To evaluate the teleost Gβγ‐PD systems, we isolated cDNAs encoding medaka Gβ1 and GβC, which selectively expressed rods and cones. Immunohistochemical studies showed that the strong reactivity of GβC but not PD‐C was detected in cone outer segments. In rod outer segments (ROS), PD‐R reactivity was stronger in light‐adapted retina than in dark‐adapted retina. Western blot analyses of fractions torn from the cryosections showed that the PD‐R concentration was low in dark‐adapted ROS. It is suggested that PD‐R is translocated to ROS and effectively downregulates the phototransduction cascade in light‐adapted rods.