Genome-wide identification and expression analysis of the SIRT gene family in Nile tilapia (Oreochromis niloticus).

The sirtuin (SIRT) family is a nicotine adenine dinucleotide (NAD+)-dependent class III histone deacetylase, which is widely involved in numerous physiological processes of organisms, such as metabolism, reproduction, and immunity. Here, based on the genomics database, comprehensive analysis of the SIRT gene in Nile tilapia (Oreochromis niloticus) was analyzed using bioinformatics methods and quantitative real-time PCR. The nine SIRT genes of O. niloticus (OnSIRT) were distributed on eight chromosomes. The OnSIRTs contain distinct sequences from 3 exons in OnSIRT4 to 16 exons in OnSIRT2, however, they share conserved domains and protein motifs. Phylogenetic analysis shows that the OnSIRTs belong to four subfamilies and are highly conserved in teleosts, and evolution is characterized primarily by purification selection. The OnSIRT genes showed diversified expression patterns in fourteen tissues of O. niloticus. OnSIRT2, OnSIRT3, OnSIRT3.2, OnSIRT6, and OnSIRT7 are mainly expressed in the gonads, especially in the ovary. OnSIRT1 and OnSIRT4 are mainly expressed in the kidney. OnSIRT5a is mainly expressed in the stomach, however, OnSIRT5b is mainly expressed in the liver and spleen. The results of this study provide a basis information for further exploration of the function and molecular mechanism of the SIRT gene family in teleosts.