Impact of host protein dynamics on picornavirus RNA 5’ noncoding region functions

 描述（由申请人提供）：小核糖核酸病毒是人类疾病的主要病原体，包括普通感冒、脊髓灰质炎、脑炎、脑膜炎、心肌炎和肝炎。它们是全球病毒性疾病的最常见原因，也是发达国家人类感染的最常见原因。然而，它们是所有哺乳动物病毒中遗传最简单的病毒之一，携带小的正义基因组RNA，其长的5'非编码区（NCR）内含有关键的调控元件。这个明显的难题可以部分解释为这些病毒劫持宿主细胞功能并改变细胞质环境以促进病毒复制的方式。小核糖核酸病毒在其复制周期中的关键步骤已经进化出复杂的机制，包括IRES介导的翻译起始、模板使用从翻译到RNA复制的转换以及逃避宿主抗病毒应答，所有这些都直接或间接涉及基因组5' NCR。解开这些机制是在这个更新应用程序中提出的实验的主题。在细胞培养模型和一系列体外实验方法中使用脊髓灰质炎病毒、人鼻病毒和柯萨奇病毒，本申请将通过提出（i）确定宿主蛋白SRp 20如何与40 S核糖体亚基相互作用以介导脊髓灰质炎病毒IRES介导的翻译起始复合物的形成，（ii）定义人鼻病毒将模板使用从翻译转换为病毒RNA合成的步骤，以及（iii）确定AUF 1负调控病毒感染的机制。这些研究的结果将揭示小核糖核酸病毒RNA的5'NCR如何控制与宿主和病毒蛋白质的无数相互作用的重要见解，所有这些都是以 一个基因挑战的RNA病毒家族的生存。这些见解应该广泛适用于在受感染人类细胞的细胞质中复制的其他正链RNA病毒，并且可能有助于识别独特的病毒-宿主界面，以开发为抗病毒治疗的靶点。

 DESCRIPTION (provided by applicant): Picornaviruses are major etiological agents of human diseases, including the common cold, poliomyelitis, encephalitis, meningitis, myocarditis, and hepatitis. They are the most common causes of viral illnesses worldwide and the most common causes of infections of humans in the developed world. Yet they are among the most genetically simple of all mammalian viruses, harboring small, positive-sense genomic RNAs with critical regulatory elements contained within their long 5' noncoding regions (NCRs). This apparent conundrum can, in part, be explained by the way these viruses hijack host cell functions and modify the cytoplasmic environment to favor viral replication. Picornaviruses have evolved complex mechanisms for key steps in their replication cycles, including IRES-mediated translation initiation, the switch in template use from translation to RNA replication, and the evasion of host anti-viral responses that all involve, directly or indirectly, the genomic 5' NCR. Unraveling these mechanisms is the over-arching theme of the experiments proposed in this renewal application. Using poliovirus, human rhinovirus, and coxsackievirus in cell culture models and an array of in vitro experimental approaches, this application will address the fundamental nature of viral processes that are directed by the 5' NCRs of genomic RNAs by proposing to (i) determine how host protein SRp20 interacts with the 40S ribosomal subunit to mediate formation of poliovirus IRES-mediated translation initiation complexes, (ii) define the steps used by human rhinovirus to switch template usage from translation to viral RNA synthesis, and (iii) determine the mechanism of AUF1 negative regulation of viral infections. Results from the proposed studies will reveal important insights into how the 5' NCRs of picornavirus RNAs control a myriad of interactions with host and viral proteins, all in the name of survival of a genetically-challenged family of RNA viruses. Such insights should be broadly applicable to other positive-strand RNA viruses that replicate in the cytoplasm of infected human cells and may help to identify unique virus-host interfaces to be developed as targets for anti-viral therapeutics.