This gene encodes a 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 and grouped into four classes.The functions of human sirtuins have not yet been determined;however,yeast sirtuin proteins are known to regulate epigenetic gene silencing and suppress recombination of rDNA.Studies suggest that the human sirtuins may function as intracellular regulatory proteins with mono-ADP-ribosyltransferase activity.The protein encoded by this gene is included in class I of the sirtuin family.Alternative splicing results in multiple transcript variants.[provided by RefSeq,Dec 2008]