TSA does not affect IFNα-induced translocation of STAT2 to nucleus and STAT2 binding to PML promoter. (A) Western blot analysis of STAT2 in nuclei of HeLa cells treated with 1000 U/mL IFNα, 500 ng/mL TSA, or both simultaneously for either 30 minutes or 8 hours. Nuclear extracts (25 μg total protein) were loaded on 8% SDS gels (Ponceau S–stained band of actin is shown for equal loading). (B) Chromatin immunoprecipitation using STAT2 antibody and PCR amplification of PML promoter region containing ISRE element (located at +606 to +618 after the most 5′ major transcription start according to Stadler et al²⁰ ). To exclude unspecific binding to G-Sepharose beads, we performed ChIP in the absence of the antibody (no Ab). The negative nontemplate control (NTC) reaction excluded unspecific PCR amplification. Cells were treated with the indicated drugs for 8 hours.