NAD-dependent histone deacetylase that is involved in nuclear silencing events. Derepresses subtelomeric silencing and increases repression in nucleolar (rDNA) silencing. Its function is negatively regulated by active nuclear export (By similarity). H2O + N(6)-acetyl-L-lysyl-[protein] + NAD(+) = 2''-O-acetyl-ADP-D-ribose + L-lysyl-[protein] + nicotinamide Binds 1 zinc ion per subunit. Belongs to the sirtuin family. Class I subfamily.