Function of histone chaperones in HSV-1 chromatin sturcture during latency, establishing maintenance and reactivation

潜伏期 HSV-1 染色质结构中组蛋白伴侣的功能、建立维持和重新激活

• 批准号: 8930277
• 负责人: David C. Bloom
• 金额: $ 22.5万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-16 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8930277
• 关键词: Address; Antiviral Agents; Binding; Biology; Blindness; CCCTC-binding factor; Cell Nucleus; Cell physiology; Cells; Chromatin; Clinical; Complex; DAXX gene; DNA; DNA Binding; Data; Deposition; Disease; Elements; Epigenetic Process; Episome; Equilibrium; Ganglia; Gene Expression; Gene Silencing; Genes; Genetic Transcription; Genital system; Genome; Herpes Labialis; Herpesvirus 1; Heterochromatin; Histone H1; Histone H1(s); Histone H3; Histone H3.3; Histones; Human; Human Herpesvirus 2; In Vitro; Indium; Infection; Infectious Skin Diseases; Lead; Lesion; Life; Life Cycle Stages; Lip structure; Lytic; Lytic Phase; Maintenance; Mediating; Modeling; Modification; Molecular; Molecular Chaperones; Nervous system structure; Neurons; Nuclear; Nuclear Protein; Nucleosomes; Oral cavity; Organism; Pain; Pathway interactions; Pilot Projects; Play; Positioning Attribute; Post-Translational Protein Processing; Process; Recruitment Activity; Recurrence; Regulatory Element; Repression; Research Personnel; Role; Severities; Simplexvirus; Staging; Symptoms; Testing; Therapeutic Intervention; Transcriptional Regulation; Variant; Viral; Viral Genes; Viral Genome; Virus; Virus Diseases; Virus Latency; afferent nerve; ds-DNA; experience; genital herpes; improved; in vivo; innovation; insight; latency associated transcript; latent infection; new therapeutic target; prevent; public health relevance; reactivation from latency; viral DNA; virus pathogenesis

 DESCRIPTION (provided by applicant): Herpes simplex virus (HSV) causes significant pain and suffering in humans. It is acquired by skin infection (typically mouth/lips for HSV-1 and genitals for HSV-2) where it replicates lytically and then spreads to the nervous system. It establishes a life-long latent infection within sensory nerve ganglia and persists as a double-stranded DNA (episome) within the nuclei of latently infected neurons. Periodically HSV reactivates from this latent state and causes cold sores (HSV-1) or genital lesions (HSV-2). The mechanism of how HSV establishes a latent infection or reactivates from latency is not understood. Over 50 million people in the US experience clinical recurrent HSV disease. HSV-1 is also the leading cause of infectious blindness in the US with over 30,000 new cases a year. While antiviral drugs can reduce the severity of symptoms, they do not block reactivation and they are not curative. Understanding how HSV interacts with the cell to regulate its lytic and latent life cycle could provide new targets for therapeutic intervention. Recent advantages in the field have demonstrated that transcriptional control of viral genes at the chromatin level plays a key role in the delicate balance between latency and reactivation, suggesting that chromatin is the key element in HSV latency. While the details of these regulatory processes are largely unknown, several recent findings have provided clues such as: evidence that HSV lytic genes are silenced by post-translational modifications of histones (epigenetic repression); insulator protein CTCF establishes epigenetic borders on viral DNA during latency, separating repressed lytic genes and active LAT region; nuclear protein DAXX and its interaction partner ATRX play a pivotal role by chaperoning the histone variants that can facilitate formation of mobile, transcriptionally active chromatin; DAXX and ATRX participate in intrinsic antiviral defenses repressing lytic infection. During latency establishing, DAXX complex participates in chromatin formation on HSV-1 DNA. In turn, this may create specific chromatin signature to establish proper loading and maintenance of CTCF at specific CTCF-binding elements of HSV genome thus creating epigenetic boundaries on this genome to regulate latency. These observations allowed us to formulate the main hypothesis of this proposal: the DAXX/ATRX-mediated loading of histone variants regulates dynamic deposition of CTCF on HSV-1 genome thus controlling appropriate chromatin formation that is critical for latency. We expect that the balanced deposition of histone variants represents a key necessary step in latency and predict that DAXX/ATRX complex plays an essential role in this process. In order to test this hypothesis we are combining the expertise of two co-investigators. Dr. Alexander Ishov is an expert in the DAXX/ATRX biology and in the analysis of intra-nuclear aspects of viral infection. Dr. David Bloom is an expert in epigenetic control of HSV gene expression and models to study HSV pathogenesis and latency. The key studies proposed in this project will investigate the involvement of DAXX/ATRX in recruiting histones variants to the regulatory elements of HSV genome and whether this alters the ability of the genome to establish and maintain latency via CTCF deposition in both in vitro and in vivo settings. These studies will determine whether DAXX/ATRX chaperone complex is involved in the regulatory balance between HSV lytic and latent infection and will provide essential data for the mechanistic understanding of this process. In addition to providing insight into the mechanism of HSV latency and reactivation, this highly innovative and focused pilot study has the potential to identify new therapeutic targets for treating HSV infections. If DAXX/ATRX were shown to have a role in regulating the switch between lytic and latent infection, this complex would be highlighted as target for anti-viral therapy.

 描述（由适用提供）：单纯疱疹病毒（HSV）在人类中引起严重的疼痛和痛苦。它是由皮肤感染（通常用于HSV-1的嘴/嘴唇和HSV-2的生殖器）获取的，在该皮肤中，它可以通过裂缝复制，然后扩散到神经系统。它在感觉神经神经节内建立了终身的潜在感染，并在潜在感染神经元的核中一直持续为双链DNA（ecipome）。定期从该潜在状态重新激活HSV，并引起唇疱疹（HSV-1）或生殖器病变（HSV-2）。 HSV如何建立潜在感染或从潜伏期中反应的机制尚不清楚。美国超过5000万人患有临床复发性HSV疾病。 HSV-1也是美国传染失明的主要原因，每年有30,000多个新病例。尽管抗病毒药物可以减轻症状的严重程度，但它们不会阻止重新激活，也无法治愈。了解HSV如何与细胞相互作用以调节其裂解和潜在的生命周期可以为治疗干预提供新的目标。该领域的最新优势表明，染色质水平的病毒基因的转录控制在潜伏期和重新激活之间的微妙平衡中起着关键作用，这表明染色质是HSV潜伏期的关键元素。尽管这些调节过程的细节在很大程度上是未知的，但最近的一些发现提供了以下线索：证据表明，HSV裂解基因被组蛋白的翻译后修饰沉默（表观遗传表示）；绝缘蛋白CTCF在潜伏期期间建立了病毒DNA的表观遗传边界，将反射的裂解基因和活性LAT区分开。核蛋白DAXX及其相互作用伴侣ATRX通过伴侣伴侣伴侣的组蛋白变体起着关键作用，从而可以促进移动，转录活性染色质的形成； DAXX和ATRX参与反映裂解感染的内在抗病毒防御。在建立潜伏期期间，DAXX复合物参与HSV-1 DNA上的染色质形成。反过来，这可能会创建特定的染色质签名，以在HSV基因组的特定CTCF结合元素上建立CTCF的适当负载和维护，从而在该基因组上产生表观遗传边界以调节潜伏期。这些观察结果使我们能够形成该建议的主要假设：DAXX/ATRX介导的组蛋白变体负载调节CTCF在HSV-1基因组上的动态沉积，从而控制适当的染色质形成，这对于潜伏期至关重要。我们期望组蛋白变体的平衡沉积代表潜伏期中的关键必要步骤，并预测DAXX/ATRX复合体在此过程中起着至关重要的作用。为了检验这一假设，我们将两个共同研究者的专业知识结合在一起。亚历山大·伊索夫（Alexander Ishov）博士是DAXX/ATRX生物学的专家，并且是病毒感染的核内方面的分析。 David Bloom博士是HSV基因表达和研究HSV发病机理和潜伏期的模型的表观遗传控制专家。该项目中提出的关键研究将研究DAXX/ATRX在募集组蛋白变体中的参与到HSV基因组的调节元素中，以及这是否会改变基因组在体外和体内环境中通过CTCF沉积确定和维持潜伏期的能力。这些研究将确定DAXX/ATRX伴侣复合物是否参与了HSV裂解和潜在感染之间的调节平衡，并将为机械理解这一过程提供基本数据。 除了洞悉HSV潜伏期和重新激活的机制外，这项高度创新且重点的试点研究还具有鉴定用于治疗HSV感染的新的治疗靶标。如果证明DAXX/ATRX在减轻裂解感和潜在感染之间的切换中起作用，则该复合物将被强调为抗病毒治疗的靶标。