At the site of infection (respiratory epithelial cells), TLR3 and TLR7 sense viral double-stranded and single-stranded RNA (ssRNA), respectively, within the endosome, while RIG-I recognizes cytosolic ssRNA or viral RNA containing 5′-triphosphate and induces Type I and III IFN responses through the transcriptional factors NF-kB and interferon regulatory factor (IRF) by interacting with mitochondrial antiviral signaling (MAVS) protein. The gene discussed is RIGI; the disease is infection.