Interferon Induced Protein With Tetratricopeptide Repeats 1 (IFIT1)

Treatment of responsive cells with interferons induces, within a few hours, a rise in the concentration of several mRNAs and proteins.An induced mRNA of about 2 kb, termed C56, was found to code for a 56-kD protein easily detected by hybridization-translation experiments. ISG56 overexpression inhibited virus-triggered activation of interferon-stimulated regulatory element (ISRE), a conserved enhancer motif recognized by activated IRF3, and the IFNB promoter. In contrast, ISG56 knockdown potentiated virus-induced activation of ISRE, NFKB, and IFNB. ISG56 interaction with MITA inhibited MITA interaction with VISA (MAVS) and TBK1. ISG56 is a mediator of negative-feedback regulation of virus-triggered induction of type I IFNs and cellular antiviral responses.