Involvement of the IRF family transcription factor IRF‐3 in virus‐induced activation of the IFN‐β gene

Abstract

The virus‐induced activation of interferon α/β (IFN‐α/β) gene transcription is essential for host defense. The IFN‐β promoter is controlled primarily by the virus‐inducible enhancer elements, the IRF‐Es. Here we show that IRF‐3, an IRF family transcription factor, translocates to the nucleus from the cytoplasm upon virus infection in NIH/3T3 cells. The nuclear IRF‐3 is phosphorylated, interacts with the co‐activators CBP/p300, and binds specifically to the IFN‐β IRF‐E. Furthermore, overexpression of IRF‐3 causes a marked increase in virus‐induced IFN‐β mRNA expression. Thus, IRF‐3 is a candidate transcription factor mediating the activation of the IFN‐β gene.