University of Cambridge, Department of Pathology, Addenbrooke's Hospital, Cambridge CB2 2QQ, UK.
Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
Sci Adv. 2022 Sep 9;8(36):eabp8655. doi: 10.1126/sciadv.abp8655.
During infection, the influenza A virus RNA polymerase produces both full-length and aberrant RNA molecules, such as defective viral genomes (DVGs) and mini viral RNAs (mvRNAs). Subsequent innate immune activation involves the binding of host pathogen receptor retinoic acid-inducible gene I (RIG-I) to viral RNAs. However, it is not clear what factors determine which influenza A virus RNAs are RIG-I agonists. Here, we provide evidence that RNA structures, called template loops (t-loops), stall the viral RNA polymerase and contribute to innate immune activation by mvRNAs during influenza A virus infection. Impairment of replication by t-loops depends on the formation of an RNA duplex near the template entry and exit channels of the RNA polymerase, and this effect is enhanced by mutation of the template exit path from the RNA polymerase active site. Overall, these findings are suggestive of a mechanism involving polymerase stalling that links aberrant viral replication to the activation of the innate immune response.
在感染过程中，甲型流感病毒 RNA 聚合酶产生全长和异常 RNA 分子，如缺陷型病毒基因组 (DVGs) 和微小病毒 RNA (mvRNA)。随后的先天免疫激活涉及宿主病原体受体视黄酸诱导基因 I (RIG-I) 与病毒 RNA 的结合。然而，尚不清楚哪些因素决定了甲型流感病毒 RNA 是 RIG-I 激动剂。在这里，我们提供的证据表明，称为模板环（t 环）的 RNA 结构会使病毒 RNA 聚合酶停滞，并通过甲型流感病毒感染期间的微小病毒 RNA (mvRNA) 促进先天免疫激活。t 环对复制的损害取决于在 RNA 聚合酶的模板进入和退出通道附近形成 RNA 双链，并且这种效应通过 RNA 聚合酶活性位点的模板出口路径的突变而增强。总的来说，这些发现提示了一种涉及聚合酶停滞的机制，它将异常病毒复制与先天免疫反应的激活联系起来。
