Key result
Positive-stranded RNA viruses capable of homologous recombination rapidly excised genomic material to evade RNAi, whereas negative-stranded viruses were effectively targeted and cleared.
The capacity to undergo homologous recombination provides positive-stranded RNA viruses an intrinsic advantage to evade RNAi-based host defenses compared to negative-stranded viruses.
Recombination enables +ssRNA virus evasion of RNAi-like pressure; leaves open its evolutionary role in vertebrate antiviral defense.
RNA interference (RNAi) is the major antiviral defense mechanism of plants and invertebrates, rendering the capacity to evade it a defining factor in shaping the viral landscape. Here we sought to determine whether different virus replication strategies provided any inherent capacity to evade RNAi in the absence of an antagonist. Through the exploitation of host microRNAs, we recreated an RNAi-like environment in vertebrates and directly compared the capacity of positive- and negative-stranded RNA viruses to cope with this selective pressure. Applying this defense against four distinct viral families revealed that the capacity to undergo homologous recombination was the defining attribute that enabled evasion of this defense. Independent of gene expression strategy, positive-stranded RNA viruses that could undergo strand switching rapidly excised genomic material, while negative-stranded viruses were effectively targeted and cleared upon RNAi-based selection. These data suggest a dynamic relationship between host antiviral defenses and the biology of virus replication in shaping pathogen prevalence.
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Aguado et al. (2018) studied Viral infection. Positive-stranded RNA viruses vs. Negative-stranded RNA viruses was evaluated on Capacity to evade RNAi-based selection. Positive-stranded RNA viruses capable of homologous recombination rapidly excised genomic material to evade RNAi, whereas negative-stranded viruses were effectively targeted and cleared.
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