Parallels among positive-strand RNA viruses, reverse-transcribing viruses and double-stranded RNA viruses

Abstract

Viruses are divided into seven classes on the basis of differing strategies for storing and replicating their genomes through RNA and/or DNA intermediates. Despite major differences among these classes, recent results reveal that the non-virion, intracellular RNA-replication complexes of some positive-strand RNA viruses share parallels with the structure, assembly and function of the replicative cores of extracellular virions of reverse-transcribing viruses and double-stranded RNA viruses. Therefore, at least four of seven principal virus classes share several underlying features in genome replication and might have emerged from common ancestors. This has implications for virus function, evolution and control.

Translation and replication of hepatitis C virus genomic RNA depends on ancient cellular proteins that control mRNA fates

“…Furthermore, efficient retrotransposition of the yeast retrovirus-like elements Ty-1 and Ty-3 also depends on Dhh1, Lsm1, and Pat1 (19). One common theme for (ϩ)RNA viruses and retroviruses is that both need to regulate the transition of the genomic RNA from translation to encapsidation (20). Thus, the dependence of at least some members of both virus groups on particularly those host proteins that are involved in the transit of cellular mRNAs from translation to another fate suggests that they have hijacked this function for their own benefit.…”

A critical link between Toll-like receptor 3 and type II interferon signaling pathways in antiviral innate immunity

“…DsRNA is a prominent activator of the innate immune system and is the transmittable genetic material of certain classes of virus or a product of most viruses as part of their life cycles (9). The cytosolic RIG-I and MDA5 receptors coordinate with each other to evoke robust type I IFN and other innate immune responses via recognition of different structural elements that are derived from viral dsRNA (10,11).…”

Host Factors in Viral Life Cycles

“…First, they all replicate their genomes through an RNA intermediate that also functions as a mRNA. Second, this mRNA is captured into protected compartments, membrane invaginations in positive-strand RNA viruses and subviral complexes in dsRNA and retrovirus, where replication takes place and competing processes such as translation are excluded [1]. The emergence of these common underlying principles suggests a common evolutionary origin and has practical implications since these shared features might provide novel targets for broad-spectrum strategies of virus control.…”