title: Identification of a unique transcript down-regulated in the retina of rainbow trout (Oncorhynchus mykiss) at smoltification.
abstract: Developmental and physiological changes in the retina of salmonid fishes occur during smoltification, a metamorphic event associated with thyroid hormone that prepares salmon for oceanic migration. These changes include loss of ultraviolet-sensitive (UVS) cone photoreceptors, switching of visual pigments, alterations in thyroid hormone regulation, and associated changes in behavior. This model provides an opportunity to study substantial neuronal development within an established retina. Little is known, however, about how higher order neurons are altered or how retinal gene expression changes during this transition. Here, we have used differential display RT-PCR and RACE-PCR to identify a previously uncharacterized gene transcript in Oncorhynchus mykiss under developmental regulation in the retina during smoltification, rtp12.5. This unique cDNA encodes a putative protein 112 amino acids long similar to a hypothetical human open reading frame located on chromosome 14.Q24.2. Differential expression was confirmed by RNA dot blot and in situ hybridization. We also present O. mykiss sep15 cDNA sequence and describe its expression in the vertebrate retina. Considering the expression pattern within retinal tissue observed by in situ hybridization, rtp12.5 may be under TH regulation and involved in neuronal remodeling of the retina during loss of UVS cones.
authors.affiliation: Department of Biology University of Victoria, Victoria, Canada.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Dann
authors.forename: W Ted
authors.initials: WT
authors.lastname: Allison
authors.forename: David B
authors.initials: DB
authors.lastname: Levin
authors.forename: Craig W
authors.initials: CW
authors.lastname: Hawryshyn
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D015536:Down-Regulation; D005136:Eye Proteins / Q000235:genetics*; D029941:Fish Proteins / Q000235:genetics*; D017403:In Situ Hybridization; D008675:Metamorphosis, Biological / Q000235:genetics*; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss / Q000235:genetics* / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012160:Retina / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
chemical_list: D018076:DNA, Complementary; D005136:Eye Proteins; D029941:Fish Proteins; D012333:RNA, Messenger