Transcriptional activities of medaka Oryzias latipes peroxisome proliferator-activated receptors and their gene expression profiles at different temperatures

摘要

Medaka Oryzias latipes peroxisome proliferator-activated receptors (PPARs) α1, α2, β, and γ were characterized for their sequence structures and transcriptional activities. While the genes encoding PPARα2, β, and γ were determined for their full length, the PPARα1 gene remained undetermined for its 5′-end region, which encodes the DNA-binding domain and a part of ligand-binding domain. Transcriptional activities of medaka PPARα2, β, and γ were also examined by reporter assay using reporter plasmids containing three copies of acyl-coenzyme A (CoA) oxidase PPAR response element. The activity of PPARα2 was 1.5- to 2.0-fold upregulated by 5,8,11,14-eicosatetraynoic, arachidonic, eicosapentaenoic, and oleic acids. The transcripts of medaka PPARs were expressed in brain, gut, heart, kidney, and liver. The messenger RNA (mRNA) levels of PPARs in brain from medaka acclimated to 10°C were higher than those from fish acclimated to 30°C. The mRNA levels of PPAR target genes encoding carnitine palmitoyltransferase-I, carnitine acylcarnitine translocase, and medium-chain acyl-CoA dehydrogenase, which are involved in β-oxidation of fatty acids in other vertebrates, were also higher in various tissues from fish acclimated to 10°C than at 30°C. Keywords β-Oxidation - Ligand assay - Medaka - PPAR - Temperature acclimation The nucleotide sequences reported in this paper have been registered into the DDBJ/EMBL/GenBank databases with accession numbers AB469411–AB469414.