Disruption of Cellular RNA Processing by Kaposi's Sarcoma-Associated Herpesvirus

卡波西肉瘤相关疱疹病毒对细胞 RNA 加工的破坏

• 批准号: 9317435
• 负责人: Britt A Glaunsinger
• 金额: $ 35.06万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-25 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9317435
• 关键词: AIDS related cancer; Acquired Immunodeficiency Syndrome; Affect; Africa; Area; Binding Proteins; Cancer Etiology; Cells; Cleaved cell; Code; Complement; Complex; Cytoplasm; DNA Polymerase II; DNA-Directed RNA Polymerase; Disease; Disease Progression; Distant; Elements; Environment; Enzymes; Etiology; Eukaryota; Exhibits; Feedback; Gene Expression; Genetic Transcription; Goals; Grant; HIV; Herpesviridae; Herpesviridae Infections; Human Herpesvirus 8; Immune Evasion; Immunosuppression; Infection; Kaposi Sarcoma; Life; Life Cycle Stages; Link; Lytic; Lytic Phase; Malignant Neoplasms; Mammalian Cell; Mediating; Messenger RNA; Nuclear; Pathway interactions; Patients; Phase; Phenotype; Play; Population; Process; Proteins; RNA; RNA Binding; RNA Caps; RNA Decay; RNA Degradation; RNA Processing; RNA chemical synthesis; Regulation; Ribonucleoproteins; Role; Signal Transduction; Specificity; Stress; Transcript; Viral; Viral Genes; Viral Proteins; Virus; Virus Replication; Yeasts; base; gammaherpesvirus; insight; link protein; lytic replication; member; novel; nuclease; pathogen; public health relevance; response; screening; success; tool

 DESCRIPTION (provided by applicant): Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of the majority of AIDS- associated cancers. It is endemic in many areas of Africa and, due to the extraordinarily high HIV burden there, Kaposi's sarcoma is emerging as one of the most common cancers on that continent. During AIDS-induced immunosuppression, KSHV replication is no longer effectively controlled, and, together with a large latently infected population of cells, contributes to disease progression. Amplification of KSHV is dependent on its ability to exert strong control over the gene expression environment of the infected cell. A primary mechanism the virus uses to regulate gene expression is to induce widespread degradation of messenger RNA (mRNA) in the cytoplasm. This phenotype plays numerous roles in the viral lifecycle and immune evasion, and is driven by a virally encoded nuclease termed SOX. Although SOX cleaves an extremely large number of transcripts, it exhibits clear specificity for RNA Polymerase II (Pol II) transcribed RNAs and does not have significant RNA binding activity. How it recognizes and is brought to its targets remains a central unanswered question in the field and is the focus of the first Aim of this proposal. We will apply bimolecular complementation-based protein interaction screening, unbiased ribonucleoprotein complex purification, and directed functional studies to pinpoint how SOX is directed to its target mRNAs. Identification and characterization of factors that mediate SOX targeting is central to understanding how KSHV maintains control of gene expression, and may similarly provide new insight into cellular strategies to govern RNA fate. The depletion of cytosolic mRNA by SOX is presumably sensed by the cell, and thus offers a unique opportunity to reveal cellular responses to broad changes in the gene expression landscape, such as those induced by pathogens. In this regard, recent results in yeast indicate the existence of feedback mechanisms to detect and respond to altered activity of different stages of gene expression. Using gamma-herpesviruses as tools, we have now discovered an analogous pathway in mammalian cells that links mRNA degradation with transcription. Activation of this pathway, which we term `transcriptional priming', impacts the rate of nascent mRNA synthesis. Though it is likely that the normal role of this host pathway is to regulate cellular gene expression in response to stress, we hypothesize that during KSHV infection its activation by SOX instead serves to enhance Pol II transcription of viral genes. Defining how this pathway is controlled and how it impacts the viral life cycle are the goals of Aim 2. Results from these studies should provide new insight into how seemingly distant stages of gene expression are integrated, and how viral pathogens like KSHV take advantage of these cellular controls to enhance their replicative success.

 描述（由适用提供）：Kaposi与肉瘤相关的疱疹病毒（KSHV）是大多数与艾滋病相关的癌症的病因学药物。它在非洲许多地区是内在的，由于那里的艾滋病毒负担极高，卡波西的肉瘤正在成为最常见的癌症之一。在艾滋病诱导的免疫抑制期间，KSHV复制不再有效地控制，并且与大量潜在感染的细胞群一起，有助于疾病进展。 KSHV的扩增取决于其对感染细胞的基因表达环境的强大控制能力。病毒用来调节基因表达的主要机制是诱导细胞质中信使RNA（mRNA）的宽度降解。该表型在病毒生命周期和免疫进化中起着许多作用，并且由称为Sox的病毒编码的核酸酶驱动。尽管Sox裂解了大量的转录物，它表现出对RNA聚合酶II（POL II）的明确特异性（POL II），并且没有重大的RNA结合活性。它如何认识并将其带入目标仍然是该领域中的一个核心未解决问题，并且是该提案的第一个目的的重点。我们将应用双分子 基于互补的蛋白质相互作用筛选，无偏的核核蛋白复合纯化以及指示功能研究以查明如何将Sox引向其靶标mRNA。介导SOX靶向的因素的识别和表征对于理解KSHV如何保持基因表达的控制至关重要，并且可以同样提供对控制RNA命运的细胞策略的新见解。细胞可能会感受到Sox的胞质mRNA的耗竭，因此提供了一个独特的机会，可以揭示对基因表达景观广泛变化的细胞反应，例如病原体引起的。在这方面，酵母的最新结果表明存在反馈机制，以检测和响应基因表达不同阶段的活性改变。现在，我们使用γ-疱疹病毒作为工具，现在发现了在哺乳动物细胞中的类似途径，将mRNA降解与转录联系起来。我们称之为“转录启动”的该途径的激活会影响新生mRNA合成的速率。尽管该宿主途径的正常作用可能是根据应激调节细胞基因的表达，但我们假设在KSHV感染期间，SOX的激活中会增强病毒基因的POL II转录。定义该路径的控制方式以及它如何影响病毒生命周期 AIM 2的目标。这些研究的结果应提供有关基因表达看似遥远阶段的整合以及KSHV（KSHV）如何利用这些细胞控制以增强其复制成功的方式的新见解。