Rhinovirus-Induced Shutoff of Cellular Responses

鼻病毒诱导的细胞反应关闭

• 批准号: 7151335
• 负责人: ANN C. PALMENBERG
• 金额: $ 16.82万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7151335
• 关键词: HeLa cells; asthma; cell type; cellular pathology; cooperative study; cytolysis; endopeptidases; enzyme activity; genetic transcription; genetic translation; genotype; host organism interaction; human genetic material tag; human tissue; immune response; laboratory mouse; laboratory rabbit; nuclear transport; pathologic process; phenotype; respiratory infections; respiratory virus; rhinovirus; tissue /cell culture; virus genetics; virus infection mechanism; virus protein; virus replication

The RNA picornaviruses have evolved wonderfully robust and effective mechanisms to express their proteins and override host defenses. Novel internal ribosomal entry sites (IRESs) allow these genomes to bypass normal translational requirements for 5' cap structures and efficiently lure the ribosomes into viral instead of cellular pathways. The captured ribosomes pass down a single, long open reading frame (ORF), creating polyproteins that are in reality, tandem linkages of all structural and enzymatic units necessary for rapid and virulent infection. Individual protein fragments are liberated co-translationally and posttranslationally in an elaborate proteolytic cascade that is a defining feature of this family. The molecular biology of picornaviruses, and in particular that of poliovirus and the closely related human rhinovirus, is perhaps one of the best understood and most thoroughly accessible experimental systems in all of biology. Basic mechanisms of IRES translation, protein processing or genome replication have been under investigation for decades and there are superb molecular and recombinant tools available for the study of every aspect of the virus lifecycle. The focus of this project is the way in which the human rhinoviruses can seditiously subvert a cell's innate immunity traps, crippling the capacity of that cell to trigger an alarm or altering the nature of the alarm itself. The molecular battleground in that first infected cell, pits two key viral proteases, 2Apro and 3Cpro, enzymes strategically honed by evolution for this particular purpose, against cellular defenses that may vary significantly according to cell-type, cell-cycle, host genetics, immune history and current medical predisposition. We propose that substantially different disease phenotypes can be triggered at their core, by the ability or inability of these proteases to shutoff of crucial cellular transcription and translational processes. Every subsequent immune and disease response is consequent to this outcome. At the ultimate molecular level, the activities of these proteases instigate the cascade of events that set off or prevent an episode of disease. The experiments in this project will examine the cleavage processes and molecular consequences by which rhinovirus infection inactivates cytoplasmic-nuclear transport, thus crippling the ability of the cell to carry out mRNA transcription, or cap-dependent translation. They will determine whether an unconditional viral-induced shutoff of nuclear transport is necessary to allow viral replication and cell lysis. Or, under conditions when these processes are only partially effective, whether a host-induced up-regulation of innate triggers then quickly escalates into a full-blown immune response, that may or may not be inappropriate for the extent and severity of actual infection. The project will also examine host shutoff activities are ubiquitous and similar in multiple human cell types, or are modulated by the genetics and/or innate immunity status of the cultures and the genotype of virus.

RNA小核糖核酸病毒已经进化出非常健壮和有效的机制来表达他们的 蛋白质和超越宿主防御系统。新的内部核糖体进入位点(IRESS)使这些基因组能够 绕过5‘端帽子结构的正常翻译要求，有效地诱使核糖体进入病毒 而不是细胞通路。捕获的核糖体向下传递一个单一的长开放阅读框架(ORF)， 创造的多蛋白实际上是，所有结构和酶单位的串联连接 快速而致命的感染。单个蛋白质片段在共翻译和翻译后被释放 在一个精心设计的蛋白水解级联中，这是这个家族的一个定义特征。分子 微小核糖核酸病毒的生物学，特别是脊髓灰质炎病毒和密切相关的人类鼻病毒的生物学 也许是所有生物学中最被理解和最彻底的实验系统之一。 IRES翻译、蛋白质加工或基因组复制的基本机制一直处于 几十年来的研究，有非常好的分子和重组工具可用于研究 病毒生命周期的每一个方面。这个项目的重点是人类鼻病毒如何 煽动颠覆细胞的先天免疫陷阱，削弱该细胞触发警报或 改变警报本身的性质。在第一个受感染细胞中分子战场，凹陷了两个关键病毒 蛋白水解酶，2APro和3CPro，是进化为这一特殊目的而战略性地磨练的酶，针对 根据细胞类型、细胞周期、宿主遗传学、免疫史的不同，细胞防御可能会有很大差异 以及目前的医疗倾向。我们认为，本质上不同的疾病表型可以是 在它们的核心，由这些蛋白酶关闭关键细胞转录的能力或无能为力所触发 和翻译过程。随后的每一次免疫和疾病反应都是由此而来的 结果。在最终的分子水平上，这些蛋白酶的活性引发了一连串的事件。 引发或防止疾病发作的东西。这个项目中的实验将检验卵裂 鼻病毒感染灭活细胞质-核的过程和分子后果 运输，从而削弱了细胞进行mRNA转录或帽子依赖的翻译的能力。 他们将确定是否有必要无条件关闭病毒诱导的核运输，以允许 病毒复制和细胞裂解。或者，在这些进程只有部分有效的情况下，无论 宿主诱导的先天诱因的上调，然后迅速升级为全面的免疫反应，即 对于实际感染的程度和严重程度，可能不合适，也可能不合适。该项目还将审查 宿主关闭活动在多种人类细胞类型中普遍存在且相似，或者受 培养物和病毒基因型别的遗传和/或天然免疫状态。