PU.1 binds to the TRAIL promoter region in both U266tetPU.1 and KMS12PEtetPU.1 cells in vivo. (a) and (b) Chromatin immunoprecipitation (ChIP) assays reveal that PU.1, but not IRF7, binds to the TRAIL promoter region. ChIP assays were performed on U266tetPU.1 (a) and KMS12PEtetPU.1 cells (b) at 1 day after PU.1 induction. Chromatin DNA was immunoprecipitated with anti-IRF7 or anti-PU.1 antibodies, or rabbit IgG as a control. After extraction of genomic DNA, PCR amplification of the TRAIL promoter and exon 1 region was performed with water (lane 1), input chromatin DNA (lane 2) or genomic DNA immunoprecipitated by rabbit IgG (lane 3), anti-IRF7 antibody (lane 4) or anti-PU.1 antibody (lane 5).