Mechanisms of Human Cytomegalovirus Latency in Primary Human Hematopoietic Cells

人原代造血细胞中人巨细胞病毒潜伏期的机制

• 批准号: 10542647
• 负责人: Felicia D Goodrum
• 金额: $ 6.51万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-19 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10542647
• 关键词: Address; Antiviral Agents; Biology; Cell physiology; Cells; Cercopithecine Herpesvirus 1; Code; Complex; Cytomegalovirus; Disease; Epidermal Growth Factor Receptor; Funding; Genes; Genome; Hematopoietic; Herpesviridae; Herpesviridae Infections; Human; Immune; Individual; Infection; Latent virus infection phase; Length; Life; Maintenance; Membrane; Modeling; Mutation; N-terminal; Pathway interactions; Phenotype; Protein Isoforms; Proteins; Recurrence; Research; Role; Signal Transduction; Solid; System; Therapeutic; Time; Transplant Recipients; Ubiquitin; Viral Genes; Virus; Virus Diseases; Virus Latency; Virus Replication; Work; base; cellular targeting; chronic infection; latent infection; molecular mass; novel; organ transplant recipient; prevent; programs; reactivation from latency; recombinant virus; stem cells; trafficking; ubiquitin-protein ligase

PROJECT SUMMARY Human cytomegalovirus (HCMV) is a β-herpesvirus that establishes a lifelong latent infection in its host. Reactivation from latency can result in life-threatening disease in immune deficient individuals, particularly stem cell and solid organ transplant recipients. Our research program has a long-standing focus on defining HCMV determinants and host interactions at the mechanistic core of latency and reactivation. In previous funding periods, we defined a polycistronic locus within the ULb' region of the HCMV genome that spans the genes UL133-UL138. Within this region, we have identified virus-coded repressors and activators of virus replication. UL138 represses replication for latency, whereas UL135 activates replication for reactivation, in part, by overcoming the repressive action of UL138. UL135 and UL138 regulate EGFR with opposing effects and together comprise a switch to control viral latency and reactivation by regulating host signaling. Recently, UL136 has emerged as a key modulator of this switch. UL136 encodes 5 alternant protein forms or isoforms (p33, p26, p25, p23, and p19, based on their molecular mass) that differ only in their N-terminal sequences. UL136 isoforms accumulate at later times relative to UL135 and UL138 in productive infection, requiring the onset of HCMV genome synthesis for maximum expression. Some UL136 isoforms are required for reactivation (p33 and p26 isoforms), while others function in latency (p23 and 19 isoforms). However, nothing is known about the mechanism by which UL136 isoforms function or their interplay with other UL133-UL138 proteins to regulate latency and reactivation. Intriguingly, the full-length, membrane-bound isoform of UL136 (p33) is unstable and targeted for rapid turnover (t1/2≤1h), whereas other UL136 isoforms are stable (t1/2>6h). Stabilization of p33 by specific mutation results in a virus that cannot maintain latency and replicates, indicating that its rapid turnover is critical for maintenance of latency. From these findings, we hypothesize that the UL136 isoforms modulate the UL135/UL138 switch to reinforce decisions to stably maintain or exit latency. We propose 3 aims to address this hypothesis. Aim 1 will determine how UL136 p33 is targeted for rapid turnover and the significance of its destabilization to the decision to maintain latency or to reactivate. Aim 2 will define epistatic interplay between the UL136 isoforms and with other UL133-UL138 proteins to modulate latency and reactivation. Aim 3 will identify UL136-host interacting partners to define the mechanisms by which UL136 modulates the switch between latency and reactivation. Our work reveals new directions in HCMV latency- specifically, distinct roles for each UL136 isoform in modulating decisions to maintain the latent infection (UL138-dominant) or to reactivate (UL135-dominant). Understanding the mechanisms by which UL136 isoforms modulate the tipping point between latency and reactivation will expand the mechanistic paradigms surrounding herpesvirus latency and reactivation.

项目摘要 人类巨细胞病毒（HCMV）是一种β-疱疹病毒，在其宿主中建立了终生的潜在感染。 潜伏期的重新激活会导致免疫缺陷个体威胁生命的疾病，尤其是 干细胞和固体器官移植受者。我们的研究计划长期关注定义 HCMV在潜伏期和重新激活的机械核心上确定和主机相互作用。在上一个 资金期，我们在HCMV基因组的ULB区域内定义了一个跨度的多元基因座 基因UL133-UL138。在该区域内，我们已经确定了病毒编码的复制品和病毒活化剂 复制。 UL138抑制了延迟的复制，而UL135激活复制的复制，在 一部分，通过克服UL138的反思行动。 UL135和UL138调节EGFR具有相反的影响 并通过控制宿主信号来完成一个开关以控制病毒潜伏期和重新激活。最近， UL136已成为此开关的关键调节器。 UL136编码5种替代蛋白质或同工型 （基于它们的分子质量，p33，p26，p25，p23和p19）仅在其N末端序列上有所不同。 UL136同工型在以后相对于UL135和UL138在产品感染中积累，需要 HCMV基因组合成的发作，以最大程度地表达。需要一些UL136同工型 重新激活（p33和p26同工型），而其他同工型在潜伏期（p23和19同工型）中起作用。但是，什么都没有 了解UL136同工型功能或与其他UL133-UL138的相互作用的机制已知 蛋白质调节潜伏期和重新激活。有趣的是，UL136的全长膜结合同工型 （p33）是不稳定的，针对快速周转（T1/2≤1H），而其他UL136同工型稳定（T1/2> 6H）。 通过特定突变对p33的稳定导致无法维持潜伏期并复制的病毒，表明 它的快速营业额对于维持延迟至关重要。从这些发现，我们假设 UL136同工型调节UL135/UL138开关以加强决定稳定或退出潜伏期的决策。我们 提案3旨在解决这一假设。 AIM 1将确定如何将UL136 p33用于快速营业额 以及其对维持潜伏期或重新激活的决定的不稳定的意义。 AIM 2将定义 UL136同工型与其他UL133-UL138蛋白之间的上皮相互作用，以调节潜伏期和 重新激活。 AIM 3将确定UL136主持人互动伙伴来定义UL136的机制 调节潜伏期和重新激活之间的切换。我们的工作揭示了HCMV潜伏期的新方向 - 具体而言，每个UL136同工型在调节潜在感染的决定中的不同作用 （UL138占主导地位）或重新激活（UL135主导）。了解UL136的机制 同工型调节潜伏期和重新激活之间的临界点将扩大机械范式 周围的疱疹病毒潜伏期和重新激活。