Disruption of Cellular Messenger RNA Processing Events by the Kaposi's Sarcoma-As

卡波西肉瘤对细胞信使 RNA 加工事件的破坏

• 批准号: 8444564
• 负责人: Britt A Glaunsinger
• 金额: $ 27.8万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-12 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8444564
• 关键词: AIDS related neoplasm; Acquired Immunodeficiency Syndrome; B-Lymphocytes; Cancer Etiology; Cell Culture Techniques; Cell Nucleus; Cell physiology; Cells; Common Neoplasm; Cytoplasm; Data; Degradation Pathway; Disease; Event; Gene Expression; Gene Expression Profile; Herpesviridae; Herpesviridae Infections; Human; Human Herpesvirus 8; Human Virus; Individual; Kaposi Sarcoma; Knowledge; Link; Lymphoproliferative Disorders; Lytic; Mediating; Messenger RNA; Modeling; Monitor; Mus; Nuclear; Pathogenesis; Pathway interactions; Patients; Phenotype; Play; Poly(A)-Binding Proteins; Polyadenylation; Proteins; Quality Control; RNA; RNA Decay; RNA Degradation; RNA Processing; RNA Stability; Research; Role; Time; Translating; Translations; Viral; Viral Proteins; Virus; Work; human disease; lytic replication; mRNA Stability; novel; protein function; public health relevance; tool

DESCRIPTION (provided by applicant): Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of the most common neoplasm in untreated AIDS patients, and is also affiliated with two B cell lymphoproliferative disorders. The lytic viral replication cycle has previously been shown to be an essential component of KSHV-induced pathogenesis. One prominent consequence of lytic KSHV infection is a near total destruction of the cellular transcriptome, termed 'host shutoff'. This phenotype is mediated by the viral SOX protein which promotes enhanced cellular messenger RNA (mRNA) degradation, likely via interception of cellular RNA stability pathways. We have identified 2 novel SOX activities linked to host shutoff: SOX induces nuclear re-localization of cytoplasmic poly(A) binding protein (PABPC), and triggers disruption of the 3' end processing of cellular mRNAs in the nucleus leading to their hyperadenylation. PABPC is a cellular protein that plays a key role in mRNA translation and stability in the cytoplasm yet has no known nuclear functions. Thus, we hypothesize that its aberrant localization in SOX-expressing cells is a significant contributor to cytoplasmic mRNA destruction. Within the nucleus, the nascent hyperadenylated cellular mRNAs are not exported, and we predict they are destroyed by cellular quality control mechanisms. Interestingly, we have preliminary data indicating that nuclear PABPC is an important driver of the hyperadenylation phenotype. Thus, KSHV appears to target PABPC to eliminate both nuclear and cytoplasmic cellular messages via distinct mechanisms. This represents a completely novel mechanism of virus-induced termination of host gene expression and, additionally, reveals for the first time in human cells a mechanism for polyadenylation-stimulated mRNA decay and a role for PABPC in the nucleus. Emerging connections between disruption of normal cellular RNA turnover pathways and human disease have highlighted the importance of understanding mechanisms by which such events become deregulated; it is in this regard that KSHV SOX represents an excellent tool to probe how pathogenic human viruses may interface with these critical cellular pathways. This proposal will explore the connections between SOX-induced PABPC import and mRNA hyperadenylation, as well as explore the contribution of cellular quality control pathways towards the ultimate destruction of these messages. Specifically, we will begin by confirming that nuclear PABPC drives hyperadenylation then proceed to dissect the mechanisms by which this occurs. PABPC is a key antagonist of the nonsense-mediated mRNA decay pathway in the cytoplasm, and we will therefore explore the potential aberrant activation of this and other quality control pathways during KSHV infection. Finally, we will monitor the contribution of host shutoff towards viral replication and pathogenesis both in cell culture and in murine models.

描述（由申请方提供）：卡波西肉瘤相关疱疹病毒（KSHV）是未经治疗的AIDS患者中最常见肿瘤的病原体，也与两种B细胞淋巴增生性疾病有关。裂解病毒复制周期以前已被证明是KSHV诱导的发病机制的重要组成部分。裂解性KSHV感染的一个突出后果是细胞转录组的几乎完全破坏，称为“宿主关闭”。该表型由病毒SOX蛋白介导，其促进增强的细胞信使RNA（mRNA）降解，可能通过拦截细胞RNA稳定性途径。我们已经确定了2种与宿主关闭相关的新SOX活性：SOX诱导细胞质多聚腺苷酸结合蛋白（PABPC）的核重定位，并触发细胞核中细胞mRNA 3'端加工的破坏，导致其过度腺苷酸化。PABPC是一种在mRNA翻译和细胞质稳定性中起关键作用的细胞蛋白，但不具有已知的核功能。因此，我们推测，其在SOX表达细胞中的异常定位是细胞质mRNA破坏的重要因素。在细胞核内，新生的高腺苷酸化的细胞mRNA不会被输出，我们预测它们会被细胞质量控制机制破坏。有趣的是，我们有初步的数据表明，核PABPC是一个重要的驱动程序的高腺苷酸化表型。因此，KSHV似乎通过不同的机制靶向PABPC以消除核和细胞质细胞信息。这代表了病毒诱导的宿主基因表达终止的一种全新机制，此外，还首次在人类细胞中揭示了多聚腺苷酸化刺激的mRNA衰变机制和PABPC在细胞核中的作用。正常细胞RNA周转途径的破坏和人类疾病之间的新出现的联系突出了理解这些事件变得失调的机制的重要性;在这方面，KSHV SOX代表了一个很好的工具，以探测致病性人类病毒如何与这些关键的细胞途径相互作用。该提案将探讨SOX诱导的PABPC输入和mRNA高腺苷酸化之间的联系，以及探索细胞质量控制途径对这些信息最终破坏的贡献。具体来说，我们将开始确认核PAPC驱动腺苷酸化，然后继续剖析这种情况发生的机制。PABPC是细胞质中无义介导的mRNA衰变途径的关键拮抗剂，因此我们将探索KSHV感染期间该途径和其他质量控制途径的潜在异常激活。最后，我们将在细胞培养和小鼠模型中监测宿主关闭对病毒复制和发病机制的贡献。