JQ1 increases BRD4 complex interaction with viral gene promoters.

HeLa cell were infected with HSV-1 at 10 MOI in the absence or presence of 500 nM JQ1 for 6 hr. Protein association and their interaction with viral gene promoters were determined by immunoprecipitation, by immunostaining, and by ChIP assays, respectively. (A) JQ1 promotes protein complex formation involving BRD4, CDK9, and Rbp-1/RNAP II. Right panel bar graphs represent quantitative measurement of protein band intensities from immunoprecipitation assay. (B) JQ1 promotes BRD4 co-localization with CDK9. The enlarged areas, labeled as a, b, and c, are presented underneath the images. DAPI (blue) staining shows the nuclei. (C, D) BRD4 association with viral and host gene promoters by qPCR measurement (C) and PCR (D). (E) JQ1 promotes viral DNA synthesis and induces BRD4 redistribution. Serum-starved HeLa cells were infected with HSV-1 (10 MOI) for 4 hr in the absence or presence of 500 nM JQ1. The cells were then labeled with EdU for another 4 hr. BRD4 (Red) was visualized by staining with anti-BRD4 antibody. Green: newly synthesized DNA.