Translational control of the innate immune response through IRF-7

摘要

Transcriptional activation of cytokines, such as type-l interferons (interferon (IFN)-α and IFN-β), constitutes the first line of antiviral defence. Here we show that translational control is critical for induction of type-l IFN production. In mouse embryonic fibroblasts lacking the translational repressors 4E-BP1 and 4E-BP2, the threshold for eliciting type-I IFN production is lowered. Consequently, replication of encephalomyocarditis virus, vesicular stomatitis virus, influenza virus and Sindbis virus is markedly suppressed. Furthermore, mice with both 4E-BP1 and 4E-BP2 genes (also known as Eif4ebp1 and Eif4ebp2, respectively) knocked out are resistant to vesicular stomatitis virus infection, and this correlates with an enhanced type-l IFN production in plasmacytoid dendritic cells and the expression of IFN-regulated genes in the lungs. The enhanced type-l IFN response in 4E-BP1~(-/-) 4E-BP2~(-/-) double knockout mouse embryonic fibroblasts is caused by upregulation of interferon regulatory factor 7 (Irf7) messenger RNA translation. These findings highlight the role of 4E-BPs as negative regulators of type-l IFN production, via translational repression of Irf7 mRNA.