Comparison of A20 protein and mRNA levels and histone modifications on the A20 promoters between HCMV and UV-HCMV infection at a high MOI. (A) HF cells were infected with HCMV or UV-HCMV at an MOI of 5 for the indicated times, and the A20 protein levels were analyzed by immunoblotting. The progression of the infection with HCMV and the lack of IE1 and IE2 expression with UV-HCMV were shown by detecting the levels of IE1 and IE2. (B) HF cells were infected as in (A) and total RNAs were prepared at the indicated time points. The A20 mRNA levels were determined by qRT-PCR. The qRT-PCR results are shown as the mean values and standard errors of three independent experiments. The insert shows the RT-PCR products of A20 and β-actin (a loading control). (C and D) HF cells were infected with HCMV or UV-HCMV at an MOI of 5. Samples were prepared at the indicated time points, and ChIP assays were performed using Abs specific for acetylated histone H4 (αAc-H4) (C) and tri-methylated histone H3 (Lys9) [αTriMe-H3 (K9)] (D). The amounts of coprecipitated DNA were determined by PCR. ChIP with non-specific immunoglobulin G (IgG) was used as a negative control.