Ontrol siRNA. Mitochondria were isolated and ATP levels were analyzed with luminometric assay. As a control, stable cell lines expressing hSuv3 or its catalytically inactive mutant hSuv3_G207V was used. Mean values of three independent experiments are shown; error bars represent standard deviations. (D) Quantification of ATP levels in 293 T-Rex cells treated with inhibitors of ATP synthesis. In al