title: The miR-33 gene is identified in a marine teleost: a potential role in regulation of LC-PUFA biosynthesis in Siganus canaliculatus.
abstract: As the first marine teleost demonstrated to have the ability to biosynthesize long-chain polyunsaturated fatty acids (LC-PUFA) from C18 PUFA precursors, rabbitfish Siganus canaliculatus provides a good model for studying the regulatory mechanisms of LC-PUFA biosynthesis in teleosts. Here the potential roles of miR-33 in such regulation were investigated. The miR-33 gene was identified within intron 16 of the gene encoding sterol regulatory element-binding protein 1 (Srebp1), an activator of LC-PUFA biosynthesis. Expression of miR-33 in rabbitfish tissues correlated with that of srebp1, while its expression in liver was highly responsive to ambient salinities and PUFA components, factors affecting LC-PUFA biosynthesis. Srebp1 activation promoted the expression of Δ4 and Δ6 Δ5 fatty acyl desaturases (Fad), key enzymes for LC-PUFA biosynthesis, accompanied by elevated miR-33 abundance in rabbitfish hepatocytes. miR-33 overexpression induced the expression of the two fad, but suppressed that of insulin-induced gene 1 (insig1), which encodes a repressor blocking Srebp proteolytic activation and has targeting sites of miR-33. These results indicated that miR-33, cooperating with Srebp1, may be involved in regulation of LC-PUFA biosynthesis by facilitating fad expression, probably through targeting insig1. To our knowledge, this is the first report of the participation of miR-33 in LC-PUFA biosynthesis in vertebrates.
authors.affiliation: Marine Biology Institute &Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, Guangdong, China.
authors.forename: Qinghao
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Marine Biology Institute &Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, Guangdong, China.
authors.forename: Cuihong
authors.initials: C
authors.lastname: You
authors.affiliation: Marine Biology Institute &Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, Guangdong, China.
authors.forename: Shuqi
authors.initials: S
authors.lastname: Wang
authors.affiliation: Marine Biology Institute &Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, Guangdong, China.
authors.forename: Yewei
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, UK.
authors.forename: Óscar
authors.initials: Ó
authors.lastname: Monroig
authors.affiliation: Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland, UK.
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Tocher
authors.affiliation: Marine Biology Institute &Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, Guangdong, China.
authors.forename: Yuanyou
authors.initials: Y
authors.lastname: Li
mesh_terms: D050156:Adipogenesis; D000818:Animals; D003001:Cloning, Molecular; D005091:Exons; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D005260:Female; D005399:Fishes / Q000235:genetics*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D022781:Hepatocytes / Q000166:cytology; D007438:Introns; D050155:Lipogenesis; D008099:Liver / Q000378:metabolism; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D010802:Phylogeny; D054712:Salinity; D051780:Sterol Regulatory Element Binding Protein 1 / Q000235:genetics*
chemical_list: D005231:Fatty Acids, Unsaturated; D035683:MicroRNAs; D051780:Sterol Regulatory Element Binding Protein 1