A TRUNCATED FORM OF THE IRF-2 TRANSCRIPTION FACTOR HAS THE PROPERTIESOF A POSTINDUCTION REPRESSOR OF INTERFERON-BETA GENE-EXPRESSION

The interferon-beta promoter binding protein, IRF-2, is proteolyticall y processed during induction by double-stranded RNA to leave an N-term inal fragment that can still bind to DNA. An N-terminal fragment that corresponds to the induction-specific product has a higher affinity fo r the promoter and is a more potent repressor of interferon-beta trans cription 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 funct ions to generate a postinduction repressor of interferon-beta expressi on.