title: A novel rod-like opsin isolated from the extra-retinal photoreceptors of teleost fish.
abstract: We have isolated a novel opsin from the pineal complex of Atlantic salmon (Salmo salar) and from the brain of the puffer fish (Fugu rubripes). These extra-retinal opsins share approximately 74% identity at the nucleotide and amino acid level with rod-opsins from the retina of these species. By PCR, we have determined that the novel rod-like opsin is not expressed in the salmon retina, and the retinal rod-opsin is not expressed in the salmon pineal. Phylogenetic analysis suggests that the rod-like opsins arose from a gene duplication event approximately 205 million years ago, a time of considerable adaptive radiation of the bony fish. In view of the large differences in the coding sequences of the pineal/brain rod-like opsins, their extra-retinal sites of expression, and phylogenetic position we have termed these novel opsins 'extra-retinal rod-like opsins' (ERrod-like opsins). We speculate that the differences between retinal rod-opsins and ERrod-like opsins have arisen from their differing photosensory roles and/or genetic drift after the gene duplication event in the Triassic.
authors.affiliation: Department of Biology, Sir Alexander Fleming Building, Imperial College of Science, Technology and Medicine, London, UK.
authors.forename: A R
authors.initials: AR
authors.lastname: Philp
authors.forename: J
authors.initials: J
authors.lastname: Bellingham
authors.forename: J
authors.initials: J
authors.lastname: Garcia-Fernandez
authors.forename: R G
authors.initials: RG
authors.lastname: Foster
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D019143:Evolution, Molecular; D005399:Fishes / Q000235:genetics*; D020440:Gene Duplication; D015723:Gene Library; D008969:Molecular Sequence Data; D020419:Photoreceptor Cells, Vertebrate / Q000737:chemistry*; D010802:Phylogeny; D010870:Pineal Gland / Q000737:chemistry; D012160:Retina / Q000737:chemistry*; D017948:Retinal Rod Photoreceptor Cells / Q000737:chemistry; D017299:Rod Opsins / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification; D020317:Salmo salar / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012754:Sharks; D013045:Species Specificity
chemical_list: D017299:Rod Opsins