Identification of RNase L-Dependent, 3'-End-Modified, Viral Small RNAs in Sindbis Virus-Infected Mammalian Cells

Girardi, Erika; Chane-Woon-Ming, Béatrice; Messmer, Mélanie; Kaukinen, Pasi; Pfeffer, Sébastien

continuous arms race with their hosts, the outcome of which might ultimately result in either viral persistence, clearance of the viral infection, or death of the infected cells. The arsenal of antiviral defenses and viral counter defense mechanisms is vast and very diverse among the different phyla of life. Plants, insects, nematodes, and fungi mostly (if not exclusively) rely upon an innate immune response, whereas mammals have evolved an adaptive response in addition to this first line of defense. In the former organisms, the antiviral component of the innate immune response is mainly based on a highly conserved process commonly referred to as RNA silencing, or RNA interference (RNAi). In this phenomenon, long double-stranded RNAs of viral origin are cleaved by the RNase Dicer into small interfering RNAs (siRNAs), which are then assembled into effector complexes that contain a member of the Argonaute (Ago) family; this results in targeted degradation of viral messenger or genomic RNAs (1) .