A truncated form of the IRF-2 transcription factor has the properties of a postinduction repressor of interferon-beta gene expression.

The interferon-beta promoter binding protein, IRF-2, is proteolytically processed during induction by double-stranded RNA to leave an N-terminal fragment that can still bind to DNA. An N-terminal fragment that corresponds to the induction-specific product has a higher affinity for the promoter and is a more potent repressor of interferon-beta transcription than the full-length precursor. The kinetics of production of the cleavage product is slower than that of activation of interferon-beta transcription. These results suggest that cleavage of IRF-2 functions to generate a postinduction repressor of interferon-beta expression.