Molecular characterization and expression patterns of two hormone-sensitive lipase genes in common carp Cyprinus carpio

The hormone-sensitive lipase (HSL) gene plays an important role in mammals’ lipid metabolism. Therefore, its function in fish is capturing increasing attention. In this study, two distinct cDNAs, designated HSL1 and HSL2, are firstly identified from common carp Cyprinus carpio. The full-length cDNA of HSL1 and HSL2 consists of 3379 bp and 2732 bp, encoding polypeptide of 693 and 847 amino acids, respectively, and shares 60.6% amino acid identity. Phylogenetic analysis suggests that HSL1 and HSL2 are derived from paralogous genes, which might have arisen during a teleost-specific genome duplication event. The two HSL mRNAs are differentially expressed, both in terms of distribution among tissues and in terms of abundance during embryogenesis. Moreover, both HSL mRNAs are expressed in various tissues, the highest in abdominal fat. Meanwhile, the two HSLs are detected at all stages of embryonic development, suggesting that they could be functional and involved in embryogenesis. In addition, the results show that the mRNA expression level of HSL2 in the high group of intramuscular fat content is significantly higher than that in the low group (P < 0.01). The research provides basic data for developing a further understanding of the function of HSL as well as molecular regulation mechanism in fat metabolism of common carp.