IRF2 recruits the BAF complex to other IFN target promoters. A IRF1 and IRF2 interact with BAF complex in nuclear extracts. Nuclear extracts prepared from HeLa cells were immunoprecipitated with the indicated antibodies. The immunoprecipitates were resolved by SDS-PAGE and blotted with BRG1 antibodies. Two percents of the nuclear extracts used for IP was loaded in lane 1 as input. B Both IRF1 and IRF2 bind to IFN target promoter without IFN-α stimulation while IRF2 dissociates from IFN target promoters after IFN-α stimulation. ChIP using chromatin from HeLa cells with or without IFN-α stimulation was performed and analyzed by q-PCR as in Figure 2B. C Interplay of IRFs and ISGF3 at IFN target promoters. ChIP assays using HeLa cells with or without stimulation with IFN-α for 12 hours were performed. The binding of IRF1, IRF2, p48, and STAT2 to promoters as indicated was analyzed by q-PCR and the data were summarized. D IRF2 but not IRF1 is required for the basal level activity of IFN target promoters. Different promoter constructs in pREP4-luc vector as indicated above the columns were co-transfected with the RNA constructs indicated below the columns into HeLa cells for 48 hours. The luciferase activity was measured as in Figure 1A.