title: Molecular and functional characterization of opsins in barfin flounder (Verasper moseri).
abstract: Green light irradiation facilitates the somatic growth of barfin flounder (Verasper moseri). However, the V. moseri visual system, which may be associated with somatic growth by acting on the endocrine system upon exposure to this particular wavelength, remains largely unexplored. Herein, we characterized the visual opsin repertoire of V. moseri to understand the molecular basis underlying this effect. The five types of visual opsins that are found in vertebrates were cloned from RNA that was extracted from the eyes of V. moseri. Notably, V. moseri possessed one pseudogene (RH2-A) and two intact (RH2-B and RH2-C) copies of "green-sensitive" opsin genes. The wavelengths of maximum absorption spectra (λmax) for each of the reconstituted photopigments were 552nm for "red-sensitive" LWS, 506nm for RH2-B, 490nm for RH2-C, 482nm and 416nm for "blue-sensitive" SWS2A and SWS2B, respectively, 367nm for "ultraviolet-sensitive" SWS1, and 494nm for "dim-light sensitive rhodopsin" RH1. The λmax of SWS2A was longer than that of any other reported vertebrate SWS2 opsin. By measuring the expression level of these opsin genes with quantitative RT-PCR in 3-, 15-, and 27-month-old fish, we found that RH2-B and SWS2A were expressed at a constant level, whereas the expression of LWS, RH2-C, SWS2B, and SWS1 opsin genes decreased, and that of RH1 increased with age. Barfin flounders inhabit inshore waters at a young age and expand their habitat to deep sea areas as they age, and green light is relatively abundant in deep water compared to the lights of other wavelengths in shallow water. Our results indicate that gene repertoire and expression profile of the opsin genes of barfin flounder are adaptive to their habitat shift that occurs during development, with some opsins acquiring a distinct λmax.
authors.affiliation: School of Marine Biosciences, Kitasato University, Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan. Electronic address: kasagi@kitasato-u.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kasagi
authors.affiliation: School of Marine Biosciences, Kitasato University, Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan.
authors.forename: Kanta
authors.initials: K
authors.lastname: Mizusawa
authors.affiliation: Hokkaido National Fisheries Research Institute, Fisheries Research Agency, Akkeshi, Hokkaido 088-1108, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Murakami
authors.affiliation: Hokkaido National Fisheries Research Institute, Fisheries Research Agency, Akkeshi, Hokkaido 088-1108, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Andoh
authors.affiliation: Stanley Electric Co., Ltd. Nakameguro, Meguro-ku, Tokyo 153-8636, Japan.
authors.forename: Sumihisa
authors.initials: S
authors.lastname: Furufuji
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Science, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-856, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Kawamura
authors.affiliation: School of Marine Biosciences, Kitasato University, Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan.
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Takahashi
mesh_terms: D000222:Adaptation, Physiological; D000375:Aging; D000818:Animals; D003001:Cloning, Molecular; D005123:Eye / Q000378:metabolism*; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D005432:Flounder / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D005786:Gene Expression Regulation; D055355:Opsins / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D058067:Wavelet Analysis
chemical_list: D029941:Fish Proteins; D055355:Opsins
keywords: Barfin flounder; Color vision; Opsin; Particular wavelength light