Molecular Genetics of HSV Reactivation

HSV 再激活的分子遗传学

• 批准号: 7146619
• 负责人: David C. Bloom
• 金额: $ 42.23万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-12-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7146619
• 关键词: DNA binding protein; RNase protection assay; gene dosage; gene expression; genetic transcription; herpes simplex virus 1; laboratory rabbit; latent virus infection; methylation; nucleic acid sequence; pathologic process; polymerase chain reaction; regulatory gene; relapse /recurrence; virus genetics; virus replication

DESCRIPTION (provided by applicant): The long-term goal of this project is to understand the molecular mechanism that governs the reactivation of Herpes Simplex Virus type 1 (HSV-1) from latency. Work during the previous funding period has focused on the role of the reactivation critical region (rcr) in this process, and whether latent gene expression was regulated in an epigenetic manner. Our key findings were that: 1) the suppression of HSV-1 lytic genes during latency is associated with histone modifications and not DNA methylation; 2) the histones associated with the rcr are maintained in a hyperacetylated state during latency; 3) CTCF-containing chromatin insulator-like elements flank the region of hyperacetylation, preventing the spread of transcriptionally active chromatin to the surrounding lytic genes and 4) following reactivation stimulus rapid deacetylation of the LAT enhancer is followed by a dramatic decrease in LAT abundance and acetylation of the ICP0 promoter. These data suggest that the rcr functions as a regulatory element that controls LAT and ICP0 transcription at the level of chromatin. Specifically, the LAT enhancer portion of the rcr and a chromatin insulator act together as a switch that regulates LAT and ICP0 in a bi-phasic manner. Based on this new data and drawing from chromatin-level regulatory models employed by cellular chromosomes, we have refined our model for the LAT region's role in reactivation. This model views the LAT region as a regulatory locus that controls the transcriptional permissiveness of ICP0 through epigenetic regulation of histone modifications. This regulatory locus consists of at least three components: 1) the LAT enhancer that controls histone modifications, and has the potential to regulate transcription of both the LAT and ICP0; 2) the CTCF-insulator elements which flank the rcr and regulate the extent of the LAT enhancer's influence, and 3) transcription of the LAT RNA itself, which we hypothesize regulates the insulator. This project will seek to prove our overall hypothesis that regulation of these three components governs the ability of HSV-1 to reactivate. HSV-1 is a persistent infection of humans that causes significant morbidity and mortality. Understanding the mechanism of how stress induces reactivation could lead to new therapies to treat and prevent recurrent disease. At a broader level, understanding the mechanism by which HSV regulates transcription via modulation of chromatin structure will increase our understanding of similar processes and pathways in cellular chromosomes, potentially leading to new therapies for developmental disorders and cancer.

描述（由申请人提供）：该项目的长期目标是了解控制 1 型单纯疱疹病毒 (HSV-1) 从潜伏期重新激活的分子机制。上一个资助期间的工作重点是重新激活关键区域（rcr）在此过程中的作用，以及潜在基因表达是否以表观遗传方式受到调节。我们的主要发现是：1）潜伏期 HSV-1 裂解基因的抑制与组蛋白修饰有关，而不是 DNA 甲基化； 2) 与 rcr 相关的组蛋白在潜伏期维持在超乙酰化状态； 3) 含有 CTCF 的染色质绝缘子样元件位于过度乙酰化区域的侧翼，防止转录活性染色质扩散到周围的裂解基因，4) 在重新激活刺激后，LAT 增强子快速脱乙酰化，随后 LAT 丰度急剧下降， ICP0 启动子的乙酰化。这些数据表明 rcr 作为调节元件在染色质水平上控制 LAT 和 ICP0 转录。具体来说，rcr 的 LAT 增强子部分和染色质绝缘体一起充当开关，以双相方式调节 LAT 和 ICP0。 基于这些新数据并借鉴细胞染色体使用的染色质水平调控模型，我们改进了 LAT 区域在重新激活中的作用模型。该模型将 LAT 区域视为一个调控位点，通过组蛋白修饰的表观遗传调控来控制 ICP0 的转录许可性。该调节位点至少由三个组成部分组成：1）控制组蛋白修饰的 LAT 增强子，并有可能调节 LAT 和 ICP0 的转录； 2）位于 rcr 侧翼并调节 LAT 增强子影响程度的 CTCF 绝缘子元件，以及 3）LAT RNA 本身的转录，我们假设其调节绝缘子。该项目将寻求证明我们的总体假设，即这三个成分的调节控制着 HSV-1 重新激活的能力。 HSV-1 是一种人类持续感染，可导致显着的发病率和死亡率。了解压力如何诱导重新激活的机制可能会导致治疗和预防复发性疾病的新疗法。在更广泛的层面上，了解 HSV 通过调节染色质结构来调节转录的机制将增加我们对细胞染色体中类似过程和途径的理解，从而可能导致发育障碍和癌症的新疗法。