我要吃瓜

Citation

Zheng X, Tocher DR, Dickson C, Bell JG & Teale AJ (2005) Highly unsaturated fatty acid synthesis in vertebrates: new insights with the cloning and characterization of a delta6 desaturase of Atlantic salmon. Lipids, 40 (1), pp. 13-24. http://www.springerlink.com/content/0024-4201/; https://doi.org/10.1007/s11745-005-1355-7

Abstract
Fish are an important source of the n-3 highly unsaturated fatty acids (HUFA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids that are crucial to the health of higher vertebrates. The synthesis of HUFA involves enzyme-mediated desaturation, and a ?5 fatty acyl desaturase cDNA has been cloned from Atlantic salmon (Salmo salar) and functionally characterized previously. Here we report cloning and functional characterisation of a ?6 fatty acyl desaturase of Atlantic salmon, and describe its genomic structure, tissue expression and nutritional regulation. A salmon genomic library was screened with a salmon ?5 desaturase cDNA and positive recombinant phage isolated and subcloned. The full-length cDNA for the putative fatty acyl desaturase was shown to comprise 2106bp containing an ORF of 1365 bp specifying a protein of 454 amino acids (GenBank accession no. AY458652). The protein sequence included three histidine boxes, two transmembrane regions, and an N-terminal cytochrome b5 domain containing the haem-binding motif HPGG, all of which are characteristic of microsomal fatty acid desaturases. Functional expression showed that this gene possessed predominantly ?6 desaturase activity. Screening and sequence analysis of the genomic DNA of a single fish revealed that the ?6 desaturase gene comprised 13 exons in 7965 bp of genomic DNA. Quantitative real time PCR assay of gene expression in Atlantic salmon showed that both ?6 and ?5 fatty acyl desaturase genes, and a fatty acyl elongase gene, were highly expressed in intestine, liver and brain, and less so in kidney, heart, gill, adipose tissue, muscle and spleen. Furthermore, expression of both ?6 and ?5 fatty acyl desaturase genes in intestine, liver, red muscle and adipose tissue was higher in salmon fed a diet containing vegetable oil than in fish fed a diet containing fish oil.

Keywords
Atlantic salmon; Salmo salar; Polyunsaturated fatty acids; biosynthesis; Desaturation; Delta-6 desaturase; cDNA; tissue expression; nutritional regulation; functional characterisation; Atlantic salmon; Fishes Nutrition; Aquaculture

Journal
Lipids: Volume 40, Issue 1

• Lipids(L9602).pdf