We continued our collaboration with Dr. Ruin Moaddel (LCI, NIA) to identify small molecule compounds that can regulate SIRT6 enzyme activity in vitro and in vivo. WE are used a bacterial expression system to produce high-purity SIRT6 protein (tag-less) for biochemical studies of respective compounds. We previously generated DT40 cells in which both alleles of the SIRT6 gene were inactivated by gene targeting. This cell line (and the parental wild type control cells) served as a test bed to validate the effects of respective small molecule compounds in this cell-based system. The read-outs of SIRT6 activity is this cell line were changes in the acetylation levels of histone in genes that are direct targets of SIRT6.