title: Cloning and functional characterization of Δ6 fatty acid desaturase (FADS2) in Eurasian perch (Perca fluviatilis).
abstract: The Eurasian perch (Perca fluviatilis) is a freshwater carnivorous species of high interest to diversify inland aquaculture. However, little is known about its ability to bioconvert polyunsaturated fatty acids (PUFAs) from plant oils into long chain polyunsaturated fatty acids (LC-PUFAs). In this study, special attention has been given to the fatty acid desaturase 2 (FADS2) which is commonly described to be a rate-limiting enzyme of the LC-PUFA biosynthesis. This work reports on the cloning, tissue expression and functional characterization of the Eurasian perch fads2, but also on the cloning of two alternative splicing transcripts named fads2-AS1 and fads2-AS2. The fads2 cDNA cloned is composed of an open reading frame (ORF) of 1338 nucleotides (nt) and encodes a protein of 445 amino acids. This deduced amino acid sequence displays the typical structure of microsomal FADS2 including two transmembrane domains and an N-terminal cytochrome b5 domain with the "HPGG" motif. Quantitative real-time PCR assay of fads2, fads2-AS1 and fads2-AS2 expressions revealed that the fads2 transcript was mainly expressed in the liver and intestine and exhibited a typical gene expression pattern of freshwater species while fads2-AS1 and fads2-AS2 genes were highly expressed in the brain, followed by the liver and intestine. Functional characterization of Eurasian perch FADS2 in transgenic yeast showed a fully functional Δ6 desaturation activity toward C18 PUFA substrates, without residual Δ5 and Δ8 desaturase activities.
authors.affiliation: Unité de Recherche en Biologie Environnementale et Evolutive (URBE), Université de Namur (UNamur), Rue de Bruxelles, 61, 5000 Namur, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: Geay
authors.affiliation: Unité de Chimie Physique Théorique et Structurale, Université de Namur (UNamur), Rue de Bruxelles 61, 5000 Namur, Belgium.
authors.forename: E
authors.initials: E
authors.lastname: Tinti
authors.affiliation: Institut des Sciences de la Vie, UCLouvain, Croix du Sud, 2/L7.05.08, 1348 Louvain-la-Neuve, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Mellery
authors.affiliation: Unité de Chimie Physique Théorique et Structurale, Université de Namur (UNamur), Rue de Bruxelles 61, 5000 Namur, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Michaux
authors.affiliation: Institut des Sciences de la Vie, UCLouvain, Croix du Sud, 2/L7.05.08, 1348 Louvain-la-Neuve, Belgium.
authors.forename: Y
authors.initials: Y
authors.lastname: Larondelle
authors.affiliation: Unité de Chimie Physique Théorique et Structurale, Université de Namur (UNamur), Rue de Bruxelles 61, 5000 Namur, Belgium.
authors.forename: E
authors.initials: E
authors.lastname: Perpète
authors.affiliation: Unité de Recherche en Biologie Environnementale et Evolutive (URBE), Université de Namur (UNamur), Rue de Bruxelles, 61, 5000 Namur, Belgium. Electronic address: patrick.kestemont@unamur.be.
authors.forename: P
authors.initials: P
authors.lastname: Kestemont
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D006801:Humans; D050602:Linoleoyl-CoA Desaturase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010471:Perches / Q000235:genetics*; D010802:Phylogeny; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D050602:Linoleoyl-CoA Desaturase
keywords: Eurasian perch; Fatty acid desaturase 2; Freshwater fish; Highly unsaturated fatty acids; Tissue expression