Molecular Cloning and Expression Analysis of Lipoprotein Lipase ( LPL ) From Pampus Argenteus

To investigate lipoprotein lipase ( LPL ) genes in lipid metabolism and their functional relationship, as well as the relationship between LPL mRNA expression and muscle and liver fat accumulation in different growth stages. Full-length cDNA sequences encoding LPL were obtained from Pampus argenteus by homologous clone and RACE methods. The sequence analysis showed that the complete cDNA sequence of LPL is 3031 bp in length. It contains a coding region of 1548bp (encoding 515 amino acids), a signal peptide. A phylogenetic analysis revealed that P. argenteus was closed to S. chuatsi , D. labrax , P. major and S. aurata etc. The distribution of LPL mRNA in different tissues of adult P. argenteus was analyzed via the semi-quantitative and Real-time PCR methods where 18S gene was used as an internal reference. It was found that the expression levels of LPL in the muscle were the highest, followed by the ovarian, heart, stomach and brain. The expression of LPL mRNA in fish liver and muscle at different growth stages (weighted 1-5 g, 5-15 g, 15-30 g, 30-50 g, 50-100 g and >100 g) were analyzed. In liver, the expression levels of LPL in the fish weighted 30-50 g were significantly higher than other groups ( P< 0.05). However, in muscle, 15-30 g were significantly higher than other groups ( P <0.05). By comparing the expression of LPL mRNA in muscles at different growth stages with the content of crude fat and ∑PUFA, it was found that the content of PUFA was negatively correlated with LPL mRNA expression and intramuscular fat content ( P< 0.05). The expression of LPL mRNA in muscle is regulated by ∑PUFA, which influences the deposition of crude fat in the muscles of the Pampus argenteus . These results suggested that expression of LPL in the liver of P. argenteus is extremely low, so that P. argenteus is not easy to have fatty liver.