RB POCKET PROTEINS AND E2F TRANSCRIPTION FACTORS IN HCMV REPLICATION

HCMV 复制中的 RB 口袋蛋白和 E2F 转录因子

• 批准号: 8359698
• 负责人: Jeremy Phillip Kamil
• 金额: $ 14.87万
• 依托单位: LOUISIANA STATE UNIV HSC SHREVEPORT
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8359698
• 关键词: Anabolism; Antiviral Agents; Apoptosis; Apoptotic; Area; BAX gene; Biological; CDKN2A gene; Cell Cycle; Cell Cycle Progression; Cells; Centers of Research Excellence; Childbirth; Cytomegalovirus; Cytomegalovirus Infections; DNA Viruses; DNA biosynthesis; Development; Disease; E2F transcription factors; Family; Funding; Gene Expression; Genes; Genetic Transcription; Grant; Immune; Immune response; Infection; Interphase Cell; Knowledge; Lead; Life; Mediating; Molecular; National Center for Research Resources; Nature; PMAIP1 gene; Pathway interactions; Patients; Phosphotransferases; Principal Investigator; Protein Kinase; Protein p53; Proteins; Research; Research Infrastructure; Resources; Rest; Role; S Phase; Source; Tumor Suppressor Proteins; United States National Institutes of Health; Virus; Virus Diseases; Work; cost; response; retinoblastoma tumor suppressor; tumor; viral DNA; virology

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Human cytomegalovirus (HCMV), a betaherpesvirus, is a frequent cause of life-threatening disease among immune compromised patients. HCMV is also the most common viral infection present at childbirth and a leading infectious cause of congenital anomalies. Understanding the molecular underpinnings of HCMV replication is crucial for the development of new therapies and antiviral drugs. During natural infection, HCMV routinely enters quiescent, resting cells that are poorly suited for the synthesis of viral DNA. One strategy by which HCMV achieves expression of cellular genes necessary for its replication is by manipulating the cell cycle. HCMV induces the infected cell to reenter the cell cycle from a resting, quiescent state (termed "G0), and ultimately arrest at the G1/S-phase boundary. One mechanism by which HCMV stimulates cell cycle progression is by inactivation of the retinoblastoma tumor suppressor protein (pRb). We and others have shown that the HCMV protein kinase UL97 phosphorylates pRb at inactivating residues. We have also shown that during infection of quiescent cells, UL97-mediated inactivation of pRb is required for wild-type levels of viral DNA synthesis, and for the expression of certain E2F-regulated cellular genes involved in deoxynucleoside biosynthesis. When active, pRb functions to repress transcription mediated by cellular E2F transcription factors (E2Fs). When pRb is inactivated, E2Fs are free to stimulate S-phase gene expression, thus permitting expression of certain cellular genes required for viral DNA synthesis. However, E2Fs also directly upregulate other genes that make the cell more sensitive to programmed cell death and, via p14ARF, E2F activity can lead to stabilization of the p53 tumor suppressor protein. While much work has been done in the area of DNA viruses and tumor suppressor proteins, many important aspects of the interplay between HCMV and the pRb and p53 tumor suppressor pathways remain poorly understood, as does the nature of the pro-apoptotic cellular response to infection to HCMV. We hypothesize that HCMV infection stimulates high levels of E2F activity, which promotes expression of cellular genes necessary for HCMV viral DNA synthesis while also triggering a pro-apoptotic response that the virus must evade. To advance knowledge in this area we shall (i) determine the role of the UL97 kinase in pRb family pocket protein inactivation, (ii): elucidate the mechanism(s) by which certain pro-apoptotic cellular genes, such as PUMA, NOXA and BAX, are induced during infection, and (iii): define the biological relevance of p53 and E2Fs in the induction of pro-apoptotic responses of the host cell during infection.

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其他NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 人巨细胞病毒（HCMV）是一种β疱疹病毒，是免疫功能低下患者中危及生命的常见疾病。HCMV也是分娩时最常见的病毒感染，也是先天性畸形的主要感染原因。 了解HCMV复制的分子基础对于开发新疗法和抗病毒药物至关重要。 在自然感染过程中，HCMV通常进入不适合病毒DNA合成的静止细胞。 HCMV实现其复制所必需的细胞基因表达的一种策略是操纵细胞周期。 HCMV诱导受感染的细胞从静息、静止状态（称为“G 0”）重新进入细胞周期，并最终停滞在G1/S期边界。 HCMV刺激细胞周期进程的一种机制是通过视网膜母细胞瘤肿瘤抑制蛋白（pRb）的失活。 我们和其他人已经表明，HCMV蛋白激酶UL 97在失活残基磷酸化pRb。 我们还表明，在感染的静止期细胞，UL 97介导的pRb的失活所需的野生型水平的病毒DNA合成，并为某些E2 F调节的细胞基因的表达参与脱氧核苷的生物合成。 当pRb被激活时，其功能是抑制由细胞E2 F转录因子（E2 Fs）介导的转录。当pRb失活时，E2 Fs自由地刺激S期基因表达，从而允许病毒DNA合成所需的某些细胞基因的表达。 然而，E2 F也直接上调使细胞对程序性细胞死亡更敏感的其他基因，并且通过p14 ARF，E2 F活性可以导致p53肿瘤抑制蛋白的稳定。 虽然在DNA病毒和肿瘤抑制蛋白领域已经做了很多工作，但HCMV与pRb和p53肿瘤抑制途径之间相互作用的许多重要方面仍然知之甚少，对HCMV感染的促凋亡细胞应答的性质也知之甚少。 我们假设HCMV感染刺激高水平的E2 F活性，其促进HCMV病毒DNA合成所必需的细胞基因的表达，同时还触发病毒必须逃避的促凋亡反应。 为了推进这一领域的知识，我们将（i）确定UL 97激酶在pRb家族口袋蛋白失活中的作用，（ii）：阐明感染期间诱导某些促凋亡细胞基因（如ETAA、NOXA和BAX）的机制，以及（iii）：定义感染期间诱导宿主细胞促凋亡反应中p53和E2 Fs的生物学相关性。