FunctionTranscriptional activator. Binds to the interferon-stimulated response element (ISRE) in IFN promoters and in the Q promoter (Qp) of EBV nuclear antigen 1 (EBNA1). Functions as a molecular switch for antiviral activity. Activated by phosphorylation in response to infection. Activation leads to nuclear retention, DNA binding, and derepression of transactivation ability.
Tissue specificityExpressed predominantly in spleen, thymus and peripheral blood leukocytes.
Sequence similaritiesBelongs to the IRF family. Contains 1 IRF tryptophan pentad repeat DNA-binding domain.
Post-translational modificationsIn response to a viral infection, phosphorylated on the C-terminal serine cluster. Phosphorylation, and subsequent activation is inhibited by vaccinia virus protein E3. TRAF6-mediated ubiquitination is required for IRF7 activation.
Cellular localizationNucleus. Cytoplasm. The phosphorylated and active form accumulates selectively in the nucleus.