title: The rhodopsin gene of the cuttlefish Sepia officinalis: sequence and spectral tuning.
abstract: The cephalopod molluscs are a group of invertebrates that occupy a wide range of oceanic photic environments. They are an ideal group of animals, therefore, in which to study the evolution of rhodopsin. The cDNA sequence of the rhodopsin gene of the cuttlefish Sepia officinalis (L.) (Sub-class Coleoidea, Order Sepiida) is presented, together with an analysis of the structure of the gene. A proline-rich C terminus is present; this structure is characteristic of cephalopod rhodopsins. In common with all invertebrate opsins studied so far, the equivalent site to the counterion in vertebrate opsins is occupied by an aromatic amino acid. An intron is present that splits codon 107, in contrast to the intronless rhodopsin gene in two species of myopsid squid. A spectral tuning model involving substitutions at only three amino acid sites is proposed for the spectral shifts between the rhodopsins of Sepia officinalis, three species of squid and Paroctopus defleini.
authors.affiliation: Department of Molecular Genetics, Institute of Ophthalmology, University College London, Bath Street, London EC1V 9EL, UK. d.hunt@ucl.ac.uk
authors.forename: J
authors.initials: J
authors.lastname: Bellingham
authors.forename: A G
authors.initials: AG
authors.lastname: Morris
authors.forename: D M
authors.initials: DM
authors.lastname: Hunt
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003118:Color Perception / Q000502:physiology; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000032:analysis*; D007438:Introns; D008297:Male; D008969:Molecular Sequence Data; D008974:Mollusca; D017956:Photoreceptor Cells, Invertebrate / Q000737:chemistry / Q000502:physiology; D016133:Polymerase Chain Reaction; D012243:Rhodopsin / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D017299:Rod Opsins / Q000737:chemistry / Q000235:genetics; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D017299:Rod Opsins; D004247:DNA; D012243:Rhodopsin