SIR2 member of the sirtuin family of proteins, homologs to the yeast Sir2 protein. Members of the sirtuin family are characterized by a sirtuin core domain. yeast sirtuin proteins are known to regulate epigenetic gene silencing and suppress recombination of rDNA.The protein encoded by this gene is included in class I of the sirtuin family. Several transcript variants are resulted from alternative splicing of this gene.