Specifically binds to the upstream regulatory region of type I IFN and IFN-inducible MHC class I genes (the interferon consensus sequence (ICS)) and represses those genes. Also acts as an activator for several genes including H4 and IL7. Constitutively binds to the ISRE promoter to activate IL7. Involved in cell cycle regulation through binding the site II (HiNF-M) promoter region of H4 and activating transcription during cell growth. Antagonizes IRF1 transcriptional activation. Interacts with BRD7, IRF2BP1 and IRF2BP2. Interacts with CREBBP in growing cells; the interaction acetylates IRF2 and regulates IRF2-dependent H4 promoter activity (By similarity). Acetylated by CBP/ p300 during cell-growth. Acetylation on Lys-75 is required for stimulation of H4 promoter activity (By similarity). The major sites of sumoylation are Lys-137 and Lys-293. Sumoylation with SUMO1 increases its transcriptional repressor activity on IRF1 and diminishes its ability to activate ISRE and H4 promoter (By similarity). Belongs to the IRF family.