Suppression of the reporter gene by epigenetic ‘two-hit’ suppressors. a. Schematic diagram of the two-hit suppressor vectors. Two epigenetic suppressor domains are fused with the GAL4 domain. After binding to the target vector, the synthetic factors suppress the target gene using two distinct epigenetic pathways. b. Relative expression of the reporter gene. Forty-eight hours post-transfection, cells were harvested for luciferase assay as described in the Figure 1 legend. Each error bar represents the standard error of mean (SEM) of three independent experiments. a: P <0.05 as compared with the pcDNA3.1 control vector; b: P <0.05 as compared with the Sss1 group.