Find in Library

Highly unsaturated fatty acids (HUFAs) are essential for mammalian health, development and growth. However, most mammals, including humans, are incapable of synthesizing n-6 and n-3 HUFAs. Fish can convert C18 unsaturated fatty acids into n-6 and n-3 HUFAs via fatty acid desaturase (Fads), in which Fads2 is a key enzyme in HUFA biosynthesis. The allo-tetraploid common carp theoretically encode two duplicated <i>fads2</i> genes. The expression patterns and desaturase functions of these two homologous genes are still unknown. In this study, the full length of the <i>fads2a</i> and <i>fads2b</i> were identified in common carp (<i>Cyprinus carpio</i>). Expression analyses indicate that both genes were mainly expressed in the liver and the expression of <i>fads2b</i> is higher than <i>fads2a</i> at different developmental stages in carp embryos. Heterogenous expression and 3D docking analyses suggested that Fads2b demonstrated stronger ∆6 and ∆5 desaturase activities than Fads2a. The core promotor regions of <i>fads2a</i> and <i>fads2b</i> were characterized and found to have different potential transcriptional binding sites. These results revealed the same desaturase functions, but different activities of two homologues of <i>fasd2</i> genes in common carp. The data showed that <i>fads2b</i> played a more important role in HUFA synthesis through both expression and functional analyses.