Ectopic PKR activation induces IFNβ expression in the absence of viral infection.

<p>(A) HT1080-GyrB-PKR cells were treated with 100 ng/ml coumermycin (coum) for 8 or 24 h, followed by western blot analysis for phospho-eIF2α. (B, C) HT1080-GyrB-PKR and HT1080-GyrB-PKR-K296H cells were treated with coumermycin or IFNγ for 8 h followed by qRT-PCR analysis to quantify expression of IFNβ (B) or GBP1 (C). Significant difference (p< 0.001) is indicated (*). (D) HT1080-GyrB-PKR cells were treated either with coumermycin (8 h) or infected with VVΔE3L (6 h), then assayed for IRF3 phosphorylation by western blotting. Detection of total IRF3 and HDAC3 indicated equal protein recovery.