Circular RNAs in HSV1 infection and antiviral immunity

项目摘要 环状RNA是最近描述的一类通过相邻外显子的反向剪接产生的RNA， 其表达在几种疾病状态和少数几种病毒感染中发生改变， 本文研究了在功能上，circRNA很少指导蛋白质合成，但与螯合有关。 microRNA和RNA结合蛋白（RNA-BPs）。CircRNA最近被认为与控制 通过提供丰富的抑制性PKR库激活双链（ds）RNA激活的eIF2 α激酶PKR， 短双链RNA序列。如果RNase L被激活， 导致circRNA的内切核糖核酸裂解。由RNA病毒复制和dsDNA产生 病毒转录从相反的基因组链，dsRNA是一种有效的病原体相关分子模式 （PAMP），其被PKR和OAS/RNase L途径识别导致突然的防御性关闭。 mRNA翻译以阻碍病毒蛋白质合成。除了可能的病毒和circRNA特异性 因此，circRNA校准dsRNA反应的潜力表明， 病毒生物学然而，受感染的细胞circRNA群体对1型单纯疱疹病毒的反应 单纯疱疹病毒1型（HSV 1）感染及其对病毒繁殖的影响仍然是未知的，这代表了一个重大的知识缺口。 该提案的总体目标是了解circRNA如何促进HSV 1感染， 抗病毒免疫我们在HSV 1感染细胞中的初步数据表明，circRNA被保护， 并且事实上通过一种机制选择性地上调 依赖于病毒立即早期蛋白ICP27。我们还发现PKR的激活依赖于 RNase L功能，表明circRNA是HSV 1感染中PKR的重要抑制剂， 降解以产生全面的抗病毒反应。这些数据与新的假设一致，即HSV 1主动地 操纵这类宿主RNA以逃避细胞内在的抗病毒防御并保持蛋白质合成 和病毒复制。本提案将分为两个目的，以充分了解1）HSV 1如何塑造 感染的细胞circRNAome和2）这些改变的功能影响。这些研究将揭示 circRNA由HSV 1操纵，并且它们在感染和免疫中的重要性对医学上重要的免疫系统起着重要作用。 人类病原体最终，这项工作可能会导致治疗各种病毒感染的新策略 并对我们理解感染、宿主防御和circRNA生物学具有重要意义。

Project Summary Circular (circ) RNAs are a recently described class of RNAs generated by backsplicing of adjacent exons, whose expression is altered in several disease states and some of the few viral infections in which they have been studied. Functionally, circRNAs rarely direct protein synthesis but have been linked to the sequestration of microRNAs and RNA binding proteins (RNA-BPs). CircRNAs were recently implicated in controlling the activation of double-stranded (ds) RNA-activated eIF2α kinase PKR by providing an abundant pool of inhibitory short duplex RNA sequences. Bound inactive PKR can be rapidly mobilized by if RNase L is activated, resulting in endoribonucleolytic cleavage of circRNAs. Generated by both RNA virus replication and dsDNA virus transcription from opposing genome strands, dsRNA is a potent pathogen associated molecular pattern (PAMP) whose recognition by PKR and the OAS/RNase L pathway leads to an abrupt defensive shutdown of mRNA translation to thwart viral protein synthesis. In addition to possible virus and circRNA -specific interactions, the potential of circRNAs to calibrate dsRNA responses therefore suggests a broad significance to virus biology. However, precisely how the infected cell circRNA population responds to herpes simplex type 1 (HSV1) infection and impacts virus reproduction remains unknown and represents a significant knowledge gap. The overall goal of this proposal is to understand how circRNAs contribute to HSV1 infection and antiviral immunity. Our preliminary data in HSV1-infected cells indicate that circRNAs are protected from degradation by the viral endoribonuclease vhs and are in fact selectively upregulated through a mechanism dependent on the viral immediate early protein ICP27. We also find that PKR activation is dependent on RNase L function, suggesting that circRNAs are important inhibitors of PKR in HSV1 infection that must be degraded for a full antiviral response. These data are consistent with the novel hypothesis that HSV1 actively manipulates this class of host RNAs to evade cell intrinsic antiviral defenses and preserve protein synthesis and viral replication. This proposal will be divided into two aims to fully understand 1) how HSV1 shapes the infected cell circRNAome and 2) the functional impact of these alterations. These studies will reveal how circRNAs are manipulated by HSV1 and their importance in infection and immunity to a medically important human pathogen. Ultimately, this work could lead to new strategies for treating a wide variety of viral infections and have significant implications for our understanding of infection, host defenses and circRNA biology.