Positive feedback regulation of type I IFN genes by the IFN‐inducible transcription factor IRF‐7

The interferon regulatory factor (IRF) family of transcription factors regulate the interferon (IFN) system, among which IRF‐3 is involved in the virus‐induced IFN‐β gene expression. Here we show that another member IRF‐7 is critical for the IFN‐α gene induction. Unlike the IRF‐3 gene, the IRF‐7 gene is induced by IFNs through activation of the ISGF3 transcription factor, and IRF‐7 undergoes virus‐induced nuclear translocation. In cells lacking p48, an essential component of IFN stimulated gene factor 3 (ISGF3), ectopic expression of IRF‐7 but not IRF‐3 can rescue the deficiency to induce IFN‐α genes. These results indicate that IRF‐7 is a key factor in the positive feedback regulation of IFN‐α/β production.

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