Virus-induced expression of type I interferon genes

Intracellular double-stranded (ds) RNA is a major sign of replication for many viruses. Host mechanisms detect the dsRNA and provoke antiviral responses. Recently, we identified retinoic acid inducible gene-I (RIG-I), which encodes a DExD/H box RNA helicase containing the caspase recruitment domain (CARD) as a critical regulator for dsRNA-induced signaling. The helicase domain with intact ATPase activity is responsible for recognition of dsRNA, and the CARD transmits downstream signals, resulting in the activation of genes including type I interferons. In this review, we discuss the function of RIG-I in antiviral innate immunity.