Viral RNA is sensed by pattern recognition receptors and results in transcriptional activation of type I interferon–stimulated genes (ISGs) and an antiviral response. Viruses enter cells by fusing with the plasma membrane or by endocytosis. After uncoating, viral RNA is exposed to the cell. Toll-like receptors recognize RNA in the endosome, and RIG-I-like receptors recognize RNA in the cytosol. They signal through adapter proteins to activate a pro-inflammatory signaling cascade and transcription of ISGs, including additional RNA sensors and genes that function in the antiviral response (e.g., IFITs, RNase L, PKR). (Image was created in BioRender.com.)
