Replicase-mediated shielding of the poliovirus replicative double-stranded RNA to avoid recognition by MDA5
Replicase-mediated shielding of the poliovirus replicative double-stranded RNA to avoid recognition by MDA5
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DOI：
10.1099/jgv.0.001111
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发表时间：
2018-09-01
影响因子：
3.8
通讯作者：
Yi, Zhigang
中科院分区：
文献类型：
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作者：
Du, Xiaoting;Zhang, Yang;Yi, Zhigang
正链RNA病毒的复制产生双链RNA（dsRNA），其被宿主模式识别受体（PRR）识别以触发先天免疫应答。病毒复制复合物（RC）的形成被认为可以保护dsRNA不被先天传感器识别。为了阐明RC介导的先天识别逃避，我们选择脊髓灰质炎病毒（PV）作为模型。我们首先发现，在PV复制过程中产生的RNA是有效的干扰素（IFN）诱导剂转染后，而没有明显的干扰素生产检测PV复制细胞。当IFN激动剂与复制的PV RNA同步引入时，PV复制并不干扰IFN的产生，并且在PV感染的细胞中，IFN激动剂诱导的IFN产生仅中度受损，但未完全消除。当用毛地黄皂苷原位透化PV感染的细胞时，病毒dsRNA容易被抗dsRNA抗体检测到，并且对RNA酶III消化具有抗性。当毛地黄皂苷透化的细胞进一步用1% triton X-100溶解时，PV的dsRNA变得对RNase III消化敏感。共定位研究表明，PV dsRNA在病毒感染的细胞中不与MDA 5共定位。鉴于PV复制复合物是突出的单膜和管状形式，病毒复制dsRNA可能被复制复合物或病毒复制酶屏蔽，以避免被RNA酶III和MDA 5接近。我们建议，复制复合物或复制酶介导的屏蔽dsRNA可能作为一种手段先天逃避。
Replication of the positive-strand RNA viruses generates double-stranded RNAs (dsRNAs) that are recognized by host pattern recognition receptors (PRRs) to trigger innate immune responses. Formation of the viral replication complex (RC) has been thought to shield dsRNA from being recognized by innate sensors. To elucidate the RC-mediated evasion of innate recognition, we selected poliovirus (PV) as a model. We first found that RNAs generated during PV replication were potent interferon (IFN) inducers upon transfection, while there was no obvious IFN production detected in PV-replicating cells. PV replication did not interfere with IFN production when IFN agonists were synchronously introduced with the replicating PV RNAs, and in PV-infected cells, IFN agonist-induced IFN production was only moderately impaired but not completely abolished. When PV-infected cells were in situ permeabilized by digitonin, viral dsRNAs were readily detected by an anti-dsRNA antibody and were resistant to RNase III digestion. When digitonin-permeabilized cells were further solubilized by 1 % triton X-100, the dsRNAs of PV became sensitive to RNase III digestion. A co-localization study showed that PV dsRNA did not co-localize with MDA5 in virally infected cells. Given that the PV replication complex is protruding single-membrane and tubular in form, viral replicative dsRNAs are probably shielded by the replication complex or the viral replicase to avoid being accessed by RNase III and MDA5. We propose that the replication complex- or replicase-mediated shielding of dsRNA may act as a means for innate evasion.