POST-TRANSCRIPTIONAL GENE REGULATION BY EBV SM PROTEIN

描述(由申请人提供)：我们的主要目标是了解EB病毒(EBV)与其宿主细胞的相互作用。EBV在B淋巴细胞中持续但间歇性地重新激活感染，并有助于淋巴和上皮性恶性肿瘤的发展，影响全球数百万人。EBV基因表达如何调控细胞基因表达。维持与宿主免疫反应的动态平衡是我们提案的总体重点。 宿主细胞和EBV基因表达的关键调节因子是早期裂解的EBV蛋白SM。SM是一种核蛋白，在EBV裂解复制过程中起重要作用，可增强mRNA的稳定、输出和加工。EBV SM还通过以高度特异的方式指导选择性剪接来调节细胞和EBV基因的表达。 我们已经证明，SM可以改变细胞STAT1 mRNA的剪接，并改变STAT1的表达模式。因此，我们的观察结果表明，SM可能在EBV的重新激活和裂解复制过程中调节宿主的先天免疫反应。了解病毒对选择性剪接的影响的关键因素，有可能为利用定向小分子或RNA抑制病毒复制开辟新的靶点。我们最近发现，SM诱导的某些干扰素刺激基因(ISGs)通过靶向特定的EBV基因来抑制EBV复制。这些细胞质ISG是在EBV重新激活过程中诱导的，这表明了一种新的假设，即当潜伏病毒产生病毒核酸和离开细胞核的蛋白质时，它们可能会检测到并作用于重新激活潜伏病毒。这一应用的一个主要假设是，细胞利用先天免疫分子来对抗内部潜伏病毒的重新激活，其方式与用于外部病原体的方式不同。这是先天免疫系统与潜伏感染相互作用的新范例，潜伏感染可能广泛适用于疱疹病毒和其他持久性病原体。因此，这一提议有可能揭示具有抗病毒活性的新型效应物的基本作用机制。了解免疫反应和EBV重新激活之间的新交叉点对于设计新的治疗策略非常重要。 因此，我们建议进行以下两个特定目的的研究：1.确定干扰素刺激基因(ISGs)抑制或增强EBV复制的机制。2.明确选择性剪接和细胞RNA结合蛋白在SM对EBV裂解复制和基因反式激活中的作用。 公共卫生相关性：爱泼斯坦-巴尔病毒(EBV)是一种感染人类的常见病毒，有助于淋巴瘤和其他癌症的发展。这项建议是为了研究EBV如何操纵受感染的细胞以避免免疫反应(宿主防御)并增强自身的复制。

DESCRIPTION (provided by applicant): Our broad goals are to understand the interactions of Epstein-Barr virus (EBV) with its host cell. EBV maintains a persistent but intermittently reactivating infection in B lymphocytes and contributes to the development of lymphoid and epithelial malignancies affecting millions of humans worldwide. How EBV gene expression modulates cellular gene expression. to maintain a homeostatic balance with the host immune response is the overall focus of our proposal. A key regulator of host cell and EBV gene expression is the early lytic EBV protein SM. SM is a nuclear protein essential for EBV lytic replication that enhances mRNA stabilization, export and processing. EBV SM also regulates cell and EBV gene expression by directing alternative splicing in a highly specific manner. We have shown that SM acts to alter splicing of cellular STAT1 mRNA and change the pattern of STAT1 expression. Our observations therefore indicate that SM may modulate host innate immune responses during the reactivation and lytic replication of EBV. Understanding the key players in viral effects on alternative splicing has the potential to open up new targets for inhibiting virus replication using directed small molecules or RNAs. We have recently found that certain interferon-stimulated genes (ISGs) induced by SM inhibit EBV replication by targeting specific EBV genes. These cytoplasmic ISGs are induced during EBV reactivation, suggesting the novel hypothesis that they may detect and act on reactivating latent viruses when they produce viral nucleic acids and proteins that exit the nucleus. A major hypothesis of this application is that cells employ innate immunity molecules to combat reactivation of internal latent viruses in ways different from those used for external pathogens. This is a new paradigm for the interaction of the innate immune system with latent infections that may broadly apply to herpesviruses and other persistent pathogens. This proposal therefore has the potential to reveal basic mechanisms of action of novel effectors with antiviral activity. Understanding new points of intersection between the immune response and EBV reactivation is important for devising new treatment strategies. We therefore propose studies with the following two specific aims: 1. Determine the mechanisms by which interferon-stimulated genes (ISGs) inhibit or enhance EBV replication. 2. Define the role of alternative splicing and cellular RNA binding proteins in EBV lytic replication and gene transactivation by SM. PUBLIC HEALTH RELEVANCE: Epstein-Barr virus (EBV), a common virus that infects humans, contributes to the development of lymphoma and other cancers. This proposal is to study how EBV manipulates the infected cell to avoid the immune response (host defenses) and enhance its own replication.