Comparison of gene expression in HeLa cells after treatment with IFN-b, IFN-g, or VPgEMCV.
We uncovered that cells infected with the encephalomyocarditis virus (EMCV) release soluble factors that induce apoptosis in uninfected cells. These factors were identified as the cytokine TNF-a and the viral protein VPgEMCV, which is necessary for viral RNA synthesis. Intriguingly, we discovered that VPgEMCV also acts as a functional mimic of IFN-?, activating its canonical signaling pathway. This includes phosphorylation of STAT1 and the induction of IRF-1 and iNOS, leading to increased nitric oxide (NO) production. The synergy of NO accumulation and TNF-a signaling initiates powerful apoptosis. To compare gene sets regulated by IFN-I signaling (IFN-b), IFN-II signaling (IFN-g), and VPgEMCV signaling, we utilized RNA-seq analysis. From the deep sequencing data, we further discovered that VPgEMCV induces a gene expression profile similar to IFN-II signaling (IFN-?), while also uniquely downregulating a distinct subset of genes. Our findings reveal that this cytokine-mimicry function of VPgEMCV regulates genes to control both viral replication and disease pathogenesis. Overall design: RNA-seq analysis comparing wildtype HeLa cells treated with IFN-b, IFN-g, or VPgEMCV 24h post-treatment.