Cloning and expression characterization of elongation of very long-chain fatty acids protein 6 () with dietary fatty acids, ambient salinity and starvation stress in .

Elongation of very long-chain fatty acids protein 6 (ELOVL6) played crucial roles in regulating energy expenditure and fatty acid metabolism. Many studies have performed to investigate the physiological roles and regulatory mechanisms of in fish and animals, while few studies were reported in crustaceans. Here we reported on the molecular cloning, tissue distribution and expression profiles in response to dietary fatty acids, ambient salinity and starvation stress in by using rapid amplification of cDNA ends (RACE) and quantitative real-time PCR. Three isoforms (named and ) were isolated from in the present study. The complete sequence of was 1345 bp, the full-length sequence of was 1419 bp, and the obtained sequence was 1375 bp in full length. The and encoded 287, 329 and 301 amino acids respectively, and exhibited the typical structural features of ELOVL protein family members. Phylogenetic analysis showed that the ELOVL6a from clustered most closely to ELOVL6 from and , while the ELOVL6b and ELOVL6c from gathered alone into a single branch. Quantitative real-time PCR exhibited that the relatively abundant expression of was observed in intestine and stomach, and the and were highly expressed in hepatopancreas. In addition, studies found that replacing fish oil with soybean oil could significantly increase the transcriptional levels of three in hepatopancreas of , and the expression of and in hepatopancreas were more sensitive to dietary fatty acids than the . Compared with the normal sea water group (27‰), the expression of sterol-regulatory element binding protein1c and were upregulated in the low salinity groups, particularly in 7‰. On the contrary, the starvation stress suppressed the expression of and . These results may contribute to understand the functions of in fatty acid synthesis and regulatory mechanisms in crustaceans.