TCERG1 depletion decreases CTD Ser2 phosphorylation. A. Total polymerase (N20), phospho-Ser5 (Ser5) or phospho-Ser2 (Ser2) polymerase II distribution at different positions of the HIV-1 genome was detected by ChIP followed by qPCR in the control and TCERG1 knockdown (KD) T-Rex-293 cell lines transfected with the pNL4-3ΔRT provirus. B. The same experiment described in panel A was performed using empty (control) and TCERG1 overexpression (OE) vectors. IgG was used as a control in all ChIP experiments. Data from four independent experiments are presented as percentages of the bound input (means ± SEM).