Defining the functional interface between the ER and flaviviruses

黄病毒属是一种相关的正链包膜RNA病毒，其显著地 影响人类健康，包括登革热（DENV）、寨卡病毒（ZIKV）。西尼罗河（西尼罗河），日本 脑炎（JEV）和黄热病（YFV）病毒。病毒感染的关键宿主因子的发现 感染揭示了细胞生物学的新方面，复杂的病毒-宿主关系， 抗病毒治疗的靶点。在进入细胞并在酸化的内体中融合后， 黄病毒RNA基因组进入细胞质，然后翻译成多聚蛋白， 在内质网（ER）加工。除了利用ER的许多功能之外， 蛋白质生产，黄病毒广泛重塑内质网膜，创造一个小生境的RNA- 依赖RNA复制。ER也是黄病毒组装的位点，这使得能够在细胞内进行病毒的复制。 新的传染性病毒的产生和分泌。因此，ER充当用于以下操作的中心点： 在黄病毒感染的生命周期中协调许多重要步骤。尽管如此， 了解ER的宿主因素和分子机制，这些因素和机制是最佳的 病毒蛋白的翻译和加工或复制小生境的组装。我们 最近进行了几次基因筛选，以确定这一过程中的重要成分。 我们在昆虫细胞中用WNV进行的全基因组RNAi筛选验证了18个与ER相关的基因 促进感染的生物学。我们的CRISPR/Cas9基因编辑筛选在人类细胞与西尼罗河病毒 还鉴定了12个ER相关基因。这些筛选集中在ER驻留蛋白上， 是西尼罗河病毒感染的关键，包括与ER易位和信号转导相关的基因， 肽加工、ER相关降解（ERAD）、蛋白质糖基化、蛋白质折叠和 脂质代谢事实上，WNV、ZIKV、JEV、DENV和YFV的感染都需要特异性的免疫应答。 宿主信号肽酶复合物（SPCS）的亚基组分，用于加工病毒 多聚蛋白，产生病毒糖蛋白，从而产生新生病毒粒子。的 本提案的目的是确定黄病毒利用特异性 ER相关宿主蛋白，以促进病毒翻译、多蛋白加工、RNA复制， 和/或组装。目的1将定义ER易位子促进 多蛋白翻译和加工，而Aim 2将剖析ER相关衰变的作用 （ERAD）促进黄病毒复制。我们的长期目标是通过以下方式确定机制： 黄病毒利用ER进行复制，因为这将揭示两个基本方面 以及抗病毒治疗的新途径。

Flaviviruses are a genus of related positive-stranded enveloped RNA viruses that significantly impact human health, including dengue (DENV), Zika (ZIKV). West Nile (WNV), Japanese encephalitis (JEV), and yellow fever (YFV) viruses. The discovery of host factors critical for viral infection reveals new aspects of cell biology, intricate virus-host relationships, and potential targets for antiviral therapeutics. After entering cells and fusing in the acidified endosome, the flavivirus RNA genome penetrates into the cytoplasm and is then translated into a polyprotein and processed at the endoplasmic reticulum (ER). In addition to utilizing many functions of the ER for protein production, flaviviruses extensively remodel ER membranes to create a niche for RNA- dependent RNA replication. The ER also is the site for flavivirus assembly, which enables the production and secretion of new infectious viruses. Thus, the ER serves as a central point for orchestrating many of the essential steps in the flavivirus infection life cycle. Despite this, little is known about the host factors and molecular mechanisms at the ER that are required for optimal translation and processing of the viral proteins or for the assembly of the replication niche. We recently have performed several genetic screens to identify important components in this process. Our genome-wide RNAi screen with WNV in insect cells validated 18 genes associated with ER biology that promote infection. Our CRISPR/Cas9 gene-editing screen in human cells with WNV also identified 12 ER-associated genes. These screens converged on ER-resident proteins as being critical for WNV infection and included genes associated with ER-translocation and signal peptide processing, ER-associated degradation (ERAD), protein glycosylation, protein folding and lipid metabolism. Indeed, infection of WNV, ZIKV, JEV, DENV, and YFV all required specific subunit components of the host signal peptidase complex (SPCS) for processing of the viral polyprotein, the production of viral glycoproteins and thus generation of nascent virions. The objective of this proposal is to define the molecular mechanisms by which flaviviruses use specific ER-associated host proteins to promote viral translation, polyprotein processing, RNA replication, and/or assembly. Aim 1 will define the mechanism by which the ER translocon promotes polyprotein translation and processing while Aim 2 will dissect the role of ER-associated decay (ERAD) in promoting flavivirus replication. Our long-term goal is to determine the mechanisms by which flaviviruses exploit the ER for their replication, as this will reveal both fundamental aspects of virology as well as new avenues for antiviral therapeutics.