RIG-I （retinoic acid-inducible gene I） is a cytosolic pattern recognition receptor （PRR） that can mediate induction of a type-I interferon （IFN1） response. RIG-I is an essential molecule in the innate immune system for recognizing cells that have been infected with a virus. These viruses can include West Nile virus, Japanese Encephalitis virus, influenza A, Sendai virus, flavivirus, and coronaviruses. RIG-I is an ATP-dependent DExD/H box RNA helicase that is activated by immunostimulatory RNAs from viruses as well as RNAs of other origins. RIG-I recognizes short double-stranded RNA （dsRNA） in the cytosol with a 5' tri- or di-phosphate end or a 5' 7-methyl guanosine （m7G） cap （cap-0）, but not RNA with a 5' m7G cap having a ribose 2′-O-methyl modification （cap-1）.