Characterization, mRNA expression and nutritional regulation of a Î”6 fatty acyl desaturase-like gene by dietary DHA levels of Perinereis aibuhitensis (Gube, 1878)
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The Î”6 fatty acyl desaturase (Î”6 Fad) enzyme plays an important role in the pathways for the biosynthesis of the highly unsaturated fatty acids (HUFA) by converting linoleic (LA, 18:2n-6) and Î±-linolenic (LNA, 18:3n-3) acids to 18:3n-6 and 18:4n-3, respectively. In the present study, a Î”6 Fad-like gene was cloned and its characterisation, tissue expression and nutritional regulation by dietary DHA (docosahexaenoic acid) levels Â were analysed in the clamworm Perinereis aibuhitensis. The full-length cDNA was 1535 bp including a 1335 bp open reading frame (ORF) encoding a polypeptide of 444 amino acids, a 113 bp 50â€™-UTR and an 87 bp 3â€™-UTR with a poly (A) tail. Sequence comparison revealed that the predicted protein shared higher homologies with Î”6 Fad from Apostichopus japonicus with 56% identify. The tissue distribution of P. aibuhitensis Î”6 Fad-like mRNA was found predominantly in intestine, followed by head, esophagus, stomach and other tissues. Quantitative real-time PCR showed that the Î”6 Fad-like transcriptional levels in intestine gradually decreased with increased content of dietary DHA.
Keywords: Gene cloning, Î”6 fatty acyl desaturase-like gene, Nutritional regulation, Perinereis aibuhitensis