C Firefly luciferase expression of constructs that contain distal and proximal enhancers of OCT4 after transfection of pRh6 and 2a2iL-RH6. The ratio of firefly luciferase expression to Renilla luciferase expression (expressed from co-transfected plasmid) measured 48 h after transfection showed proximal enhancer activity in pRH6 and distal enhancer activation in 2a2iL-RH6. OCT4 PE-Luc ***P<0.001, OCT4 DE-Luc *P<0.05 (t-test). Data presented as mean ± SD (n=3). 