HEK293 cells were transfected with siCTL or siDDX5. The next day, the cells that received siDDX5 were subsequently transfected with empty pcDNA3 vector (-), expression vectors encoding Flag-DDX5 (WT), or Flag-DDX5-RK (RK). The cells were subjected to Western blotting to visualize Flag-DDX WT and RK expression. Pol II ChIP and DRIP analysis of β-actin gene were performed. For the ChIP analysis, the Y-axis shows the signal-to-noise ratio of RNA Pol II IP relative to control IgG IP. The graphs show the average and S.E.M. from at least three independent experiments. Statistical significance was assessed using Student's t-test. *: p < 0.05; **: p < 0.01 and ****: p < 0.0001. 