ICP22 inhibits the recruitment of P-TEFb to HSV-1 gene promoter regions.

<p>(A) The effect of ICP22 on recruitment of P-TEFb to the CMV IE promoter. CHO-K1 cells were co-transfected for 40 h with pRL-CMV plasmid containing the CMV IE promoter and ICP22 expression plasmid or pcDNA3 as a control, then subjected to ChIP assays. (B) ICP22 inhibits the recruitment of P-TEFb to promoter regions of HSV-1α-, β- and γ-genes. CHO-K1 cells were co-transfected for 40 h with reporter plasmids containing α4, TK or VHS promoter and ICP22 expression plasmid or pcDNA3 as a control as indicated and subjected to ChIP assays. Antibodies specific for CyclinT1 or control rabbit IgG were used for immunoprecipitation. The precipitated DNA was analyzed by RT-PCR using primers specific for the promoter regions of CMV IE, HSV-1 α4, TK, and VHS. The values are the percentage of immunoprecipitated input DNA relative to the control group transfected with pcDNA3. Error bars represent the standard deviation with triplicate samples. * P<0.05 by student's t-test.