Terminal uridylyltransferases target RNA viruses as part of the innate immune system.

Abstract

RNA viruses are a major threat to animals and plants. RNA interference (RNAi) and the interferon response provide innate antiviral defence against RNA viruses. Here we performed a large-scale screen using C.elegans and its natural pathogen, the Orsay virus (OrV), and identified cde-1 as important for antiviral defence. CDE-1 is a homologue of the mammalian TUT4/7 terminal uriddylytransferases; its catalytic activity is required for its antiviral function. CDE-1 uridylates the 3' end of the OrV RNA genome and promotes its degradation, independently of the RNAi pathway. Likewise, TUT4/7 leads to increased JAV mRNA and protein levels. We have defined 3' terminal uridylation of viral RNAs as a conserved antiviral defines mechanism.