RECIPROCAL INTERACT - JVC T-ANTIGEN AND HOST REG FACTORS

交互作用 - JVC T 抗原和宿主调节因子

• 批准号: 6652073
• 负责人: Kamel Khalili
• 金额: $ 27.4万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-30 至 2004-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6652073
• 关键词: Polyomavirus hominis 2; SDS polyacrylamide gel electrophoresis; animal tissue; cell cycle proteins; enzyme linked immunosorbent assay; flow cytometry; gene expression; genetic transcription; glia; immunoprecipitation; laboratory rat; p53 gene /protein; pathologic process; progressive multifocal leukoencephalopathy; protein protein interaction; protein structure function; regulatory gene; tissue /cell culture; tumor antigens; virus infection mechanism; virus protein; western blottings

Progressive Multifocal Leukoencephalopathy (PML) is a fatal demyelinating disease of the central nervous system (CNS) affecting patients with immunosuppressive disorders, especially those infected with the human immunodeficiency virus type 1 (HIV-1). The human neurotropic polyomavirus, JCV, is the established etiologic agent of this disease which has the ability to productively infect and destroy oligodendrocytes, a subclass of glial cells that is responsible for production of myelin proteins and myelin sheaths in brain. The unique ability of JCV to replicate in oligodendrocytes rests on the activation of viral early gene transcription by a series of regulatory proteins present in glial cells. The product of the viral early gene, T-antigen, along with glial regulatory proteins, ensure subsequent events during the lytic cycle which include transcription of the viral late genes and replication of viral DNA. In addition to demyelination of white matter, histologic analysis of PML brain has revealed several morphological abnormalities including the appearance of enlarged oligodendrocytes with loss of normal chromatin, the presence of giant, bizarre astrocytes with pleiomorphic nuclei and mitotic figures in areas with no evidence for active viral replication. These observations suggest that expression of the viral early protein, T-antigen, in the absence of lytic infection, may interfere with host regulatory mechanisms, such as cell cycle circuitry pathways, to induce morphological alterations which are seen in pathological specimens of PML brain. In support of this concept, results from transgenic mice have indicated that expression of the JCV early protein, T-antigen, by a transgene containing the sequence for only the viral early genes induces dysmyelination of the CNS and several histological abnormalities similar to those seen in PML brain. According to our earlier results, the association of JCV T-antigen with myelin gene regulatory proteins and functional inactivation of these proteins may be responsible for the reduced levels of myelin gene expression in the brains of experimental animals. As such, in this research project we propose to: 1) investigate the molecular pathway whereby the JCV early protein, T-antigen, in the absence of viral lytic infection, may affect oligodendrocyte and astrocyte cell function; and 2) determine the molecular mechanism by which the JCV early protein, T-antigen, through its association with host regulatory proteins orchestrates viral gene expression and replication during lytic infection of glial cells. Such comprehensive studies of viral host interaction at the molecular level should enable us to understand the molecular pathogenesis of viral-induced CNS disorders and provide us with critical information and biological reagents for therapeutic intervention.

进行性多焦点白细胞病（PML）是影响免疫抑制疾病的患者，尤其是感染人类免疫缺陷病毒1型（HIV-1）的患者，是一种致命的中枢神经系统脱髓鞘疾病（CNS）。 人类神经性多瘤病毒JCV是该疾病的既定病因学药，它具有有效感染和破坏少突胶质细胞的能力，这是glial细胞的子类，该子类负责产生大脑中髓磷脂蛋白和髓磷脂鞘。 JCV在少突胶质细胞中复制的独特能力取决于神经胶质细胞中存在的一系列调节蛋白的病毒早期基因转录的激活。 病毒早期基因T-抗原以及神经胶质调节蛋白的乘积确保在裂解周期期间的后续事件，包括病毒后期基因的转录和病毒DNA的复制。 除白质的脱髓鞘外，对PML脑的组织学分析还显示出几种形态异常，包括出现增大的少突胶质细胞而出现正常染色质的损失，具有多型核和有害性核的巨大，怪异的星形胶质细胞的存在，没有任何证据表明具有活跃的病毒性证据。这些观察结果表明，在没有裂解感染的情况下，病毒早期蛋白T-抗原的表达可能会干扰宿主调节机制，例如细胞周期回路途径，以诱导在PML脑的病理标本中看到的形态改变。 为了支持这一概念，转基因小鼠的结果表明，通过仅包含病毒早期基因的序列的转基因的JCV早期蛋白T-抗原的表达会诱导中枢神经系统的抑制和几种与PML脑相似的组织学异常。 根据我们较早的结果，JCV T-抗原与髓磷脂基因调节蛋白的关联以及这些蛋白质的功能失活可能是导致实验动物大脑中髓磷脂基因表达水平降低的。 因此，在该研究项目中，我们建议：1）研究分子途径，在没有病毒裂解感染的情况下JCV早期蛋白T-抗原可能会影响少突胶质细胞和星形胶质细胞功能； 2）确定JCV早期蛋白T-抗原通过与宿主调节蛋白的关联来调节神经胶质细胞裂解感染过程中病毒基因表达和复制的分子机制。这种对分子水平的病毒宿主相互作用的全面研究应使我们能够了解病毒诱导的中枢神经系统疾病的分子发病机理，并为我们提供用于治疗干预的关键信息和生物试剂。