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Highly unsaturated fatty acid synthesis in marine fish: cloning, functional characterization, and nutritional regulation of fatty acyl delta 6 desaturase of Atlantic cod (Gadus morhua L.).
Lipids 2006; 41(11):1003-16L

Abstract

This study reports the cloning, functional characterization, tissue expression, and nutritional regulation of a delta6 fatty acyl desaturase of Atlantic cod (Gadus morhua). PCR primers were designed based on the sequences of conserved motifs in available fish desaturases and used to isolate a cDNA fragment from cod liver, with full-length cDNA obtained by rapid amplification of cDNA ends. The cDNA for the putative desaturase was shown to comprise 1980 bp, including a 261-bp 5'-UTR, a 375-bp 3'-UTR, and an ORF of 1344 bp that specified a protein of 447 amino acids. The protein sequence included three histidine boxes, two transmembrane regions, and an N-terminal cytochrome b5 domain containing the heme-binding motif HPGG, all characteristic of microsomal fatty acyl desaturases. The cDNA displayed delta6 desaturase activity in a yeast expression system. Quantitative real-time PCR assay of gene expression in cod showed that the delta6 desaturase gene was expressed highly in brain, to a slightly lesser extent in liver, kidney, intestine, red muscle, and gill, and at much lower levels in white muscle, spleen, and heart. The expression of the delta6 desaturase gene did not appear to be under significant nutritional regulation, with levels in liver and intestine being barely altered in fish fed a vegetable oil blend, in comparison with levels in fish fed fish oil. This was reflected in enzyme activity, as hepatocytes or enterocytes showed very little highly unsaturated FA biosynthesis activity irrespective of diet. Further studies are required to determine why the delta6 desaturase appears to be barely functional in cod under the conditions tested.

Authors+Show Affiliations

Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, United Kingdom. d.r.tocher@stir.ac.ukNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17263300

Citation

Tocher, Douglas R., et al. "Highly Unsaturated Fatty Acid Synthesis in Marine Fish: Cloning, Functional Characterization, and Nutritional Regulation of Fatty Acyl Delta 6 Desaturase of Atlantic Cod (Gadus Morhua L.)." Lipids, vol. 41, no. 11, 2006, pp. 1003-16.
Tocher DR, Zheng X, Schlechtriem C, et al. Highly unsaturated fatty acid synthesis in marine fish: cloning, functional characterization, and nutritional regulation of fatty acyl delta 6 desaturase of Atlantic cod (Gadus morhua L.). Lipids. 2006;41(11):1003-16.
Tocher, D. R., Zheng, X., Schlechtriem, C., Hastings, N., Dick, J. R., & Teale, A. J. (2006). Highly unsaturated fatty acid synthesis in marine fish: cloning, functional characterization, and nutritional regulation of fatty acyl delta 6 desaturase of Atlantic cod (Gadus morhua L.). Lipids, 41(11), pp. 1003-16.
Tocher DR, et al. Highly Unsaturated Fatty Acid Synthesis in Marine Fish: Cloning, Functional Characterization, and Nutritional Regulation of Fatty Acyl Delta 6 Desaturase of Atlantic Cod (Gadus Morhua L.). Lipids. 2006;41(11):1003-16. PubMed PMID: 17263300.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Highly unsaturated fatty acid synthesis in marine fish: cloning, functional characterization, and nutritional regulation of fatty acyl delta 6 desaturase of Atlantic cod (Gadus morhua L.). AU - Tocher,Douglas R, AU - Zheng,Xiaozhong, AU - Schlechtriem,Christian, AU - Hastings,Nicola, AU - Dick,James R, AU - Teale,Alan J, PY - 2007/2/1/pubmed PY - 2007/10/11/medline PY - 2007/2/1/entrez SP - 1003 EP - 16 JF - Lipids JO - Lipids VL - 41 IS - 11 N2 - This study reports the cloning, functional characterization, tissue expression, and nutritional regulation of a delta6 fatty acyl desaturase of Atlantic cod (Gadus morhua). PCR primers were designed based on the sequences of conserved motifs in available fish desaturases and used to isolate a cDNA fragment from cod liver, with full-length cDNA obtained by rapid amplification of cDNA ends. The cDNA for the putative desaturase was shown to comprise 1980 bp, including a 261-bp 5'-UTR, a 375-bp 3'-UTR, and an ORF of 1344 bp that specified a protein of 447 amino acids. The protein sequence included three histidine boxes, two transmembrane regions, and an N-terminal cytochrome b5 domain containing the heme-binding motif HPGG, all characteristic of microsomal fatty acyl desaturases. The cDNA displayed delta6 desaturase activity in a yeast expression system. Quantitative real-time PCR assay of gene expression in cod showed that the delta6 desaturase gene was expressed highly in brain, to a slightly lesser extent in liver, kidney, intestine, red muscle, and gill, and at much lower levels in white muscle, spleen, and heart. The expression of the delta6 desaturase gene did not appear to be under significant nutritional regulation, with levels in liver and intestine being barely altered in fish fed a vegetable oil blend, in comparison with levels in fish fed fish oil. This was reflected in enzyme activity, as hepatocytes or enterocytes showed very little highly unsaturated FA biosynthesis activity irrespective of diet. Further studies are required to determine why the delta6 desaturase appears to be barely functional in cod under the conditions tested. SN - 0024-4201 UR - https://www.unboundmedicine.com/medline/citation/17263300/Highly_unsaturated_fatty_acid_synthesis_in_marine_fish:_cloning_functional_characterization_and_nutritional_regulation_of_fatty_acyl_delta_6_desaturase_of_Atlantic_cod__Gadus_morhua_L___ L2 - https://link.springer.com/article/10.1007/s11745-006-5051-4 DB - PRIME DP - Unbound Medicine ER -