Molecular Characterization, Tissue Distribution and Differential Nutritional Regulation of Three n-3 LC-PUFA Biosynthesis-Related Genes in Hybrid Grouper (Epinephelus fuscoguttatus ♀×Epinephelus lanceolatus ♂)

Abstract

Elongases of very long-chain fatty acids (Elovls) and fatty acid desaturases (Fads) are crucial enzymes involved in the biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFAs). In this paper, we report the molecular cloning and characterization of three genes from the marine teleost Epinephelus fuscoguttatus ♀× Epinephelus lanceolatus ♂, and analyzed tissue distribution and their expression in response to dietary n-3 LC-PUFA levels after a 42-day feeding experiment. The elovl5, elovl8 and fads2 genes encoded 294, 263 and 445 amino acids, respectively, which exhibited all the characteristics of the Elovl and Fads family. Tissue distribution analysis revealed that elovl5, elovl8 and fads2 were widely transcribed in various tissues, with the highest level in the brain, as described in other carnivorous marine teleosts. The transcript levels of elovl5, elovl8 and fads2 in the liver were significantly affected by dietary n-3 LC-PUFA, and higher LC-PUFA levels repressed their expression. These results demonstrated, for the first time, the presence and nutritional modulation of elovl5, elovl8 and fads2 cDNA in the juvenile hybrid grouper. Further studies are needed to determine the functional characterization of these genes and explore the mechanism of these genes when regulated by dietary fatty lipid profiles in this species.