IFIH1 and infection: In particular, among RLR members, retinoic acid-inducible genes-I (RIG-I) senses 5′-triphosphate (5′-ppp)-containing short dsRNA, while melanoma differentiation-associated protein 5 (MDA5) detects long dsRNA or aggregated viral RNA; thus, these two RLRs turn on the innate immune response associated with infection of RNA viruses as well as DNA viruses.