title: Regulatory function of conserved sequences upstream of the long-wave sensitive opsin genes in teleost fishes.
abstract: Vertebrate opsin genes often occur in sets of tandem duplicates, and their expression varies developmentally and in response to environmental cues. We previously identified two highly conserved regions upstream of the long-wave sensitive opsin (LWS) gene cluster in teleosts. This region has since been shown in zebrafish to drive expression of LWS genes in vivo. In order to further investigate how elements in this region control opsin gene expression, we tested constructs encompassing the highly conserved regions and the less conserved portions upstream of the coding sequences in a promoter-less luciferase expression system. A ∼4500 bp construct of the upstream region, including the highly-conserved regions Reg I and Reg II, increased expression 100-fold, and successive 5' deletions reduced expression relative to the full 4.5 Kb region. Gene expression was highest when the transcription factor RORα was co-transfected with the proposed regulatory regions. Because these regions were tested in a promoter-less expression system, they include elements able to initiate and drive transcription. Teleosts exhibit complex color-mediated adaptive behavior and their adaptive significance has been well documented in several species. Therefore these upstream regions of LWS represent a model system for understanding the molecular basis of adaptive variation in gene regulation of color vision.
authors.affiliation: Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada V5A 1S6.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Tam
authors.forename: Corey T
authors.initials: CT
authors.lastname: Watson
authors.forename: Shabnam
authors.initials: S
authors.lastname: Massah
authors.forename: Addie M
authors.initials: AM
authors.lastname: Kolybaba
authors.forename: Felix
authors.initials: F
authors.lastname: Breden
authors.forename: Gratien G
authors.initials: GG
authors.lastname: Prefontaine
authors.forename: Timothy V
authors.initials: TV
authors.lastname: Beischlag
mesh_terms: D000818:Animals; D055253:Color Vision / Q000235:genetics* / Q000502:physiology; D055358:Cone Opsins / Q000235:genetics* / Q000378:metabolism; D017124:Conserved Sequence / Q000502:physiology*; D004742:Enhancer Elements, Genetic; D005399:Fishes / Q000235:genetics*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D008156:Luciferases; D011485:Protein Binding / Q000235:genetics; D018168:Receptors, Retinoic Acid / Q000378:metabolism*; D017949:Retinal Cone Photoreceptor Cells; D000072482:Retinoic Acid Receptor alpha; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D055358:Cone Opsins; D018168:Receptors, Retinoic Acid; D000072482:Retinoic Acid Receptor alpha; D014157:Transcription Factors; D008156:Luciferases