Reciprocal Interaction of JCV T-antigen and host regulatory factors

JCV T 抗原与宿主调节因子的相互作用

• 批准号: 6353134
• 负责人: Kamel Khalili
• 金额: $ 28.78万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2001-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6353134
• 关键词: Polyomavirus hominis 2; astrocytes; cell cycle proteins; gene interaction; genetic promoter element; genetically modified animals; glia; host organism interaction; immediate early protein; laboratory mouse; myelinopathy; neurotropic virus; regulatory gene; transcription factor; transfection /expression vector; virus antigen; virus cytopathogenic effect; virus genetics; virus replication

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 to 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 astroyctes 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-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 hot 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 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 regents for therapeutic intervention.

进行性多灶性白质脑病（PML）是一种中枢神经系统（CNS）的致死性脱髓鞘疾病，影响免疫抑制疾病患者，尤其是感染1型人类免疫缺陷病毒（HIV-1）的患者。人嗜神经性多瘤病毒JCV是该疾病的确定病原体，其具有有效感染和破坏少突胶质细胞的能力，少突胶质细胞是负责脑中髓鞘蛋白和髓鞘产生的神经胶质细胞的亚类。JCV在少突胶质细胞中复制的独特能力依赖于神经胶质细胞中存在的一系列调节蛋白激活病毒早期基因转录。病毒早期基因的产物T抗原沿着神经胶质调节蛋白，确保裂解周期期间的后续事件，包括病毒晚期基因的转录和复制，以确保裂解周期期间的后续事件，包括病毒晚期基因的转录和病毒DNA的复制。除了白色物质脱髓鞘外，PML脑的组织学分析还显示了几种形态学异常，包括出现增大的少突胶质细胞伴正常染色质丢失，在无活性病毒复制证据的区域存在具有多形核和有丝分裂像的巨大奇异星形细胞。这些观察结果表明，表达的病毒早期蛋白，T-活跃的病毒复制的证据。这些观察结果表明，在不存在裂解性感染的情况下，病毒早期蛋白T抗原的表达可能干扰热调节机制，如细胞周期电路通路，以诱导在PML脑病理标本中观察到的形态学改变。为了支持这一概念，转基因小鼠的结果表明，通过仅含有病毒早期基因序列的转基因表达JCV早期蛋白（T抗原）诱导CNS髓鞘形成障碍和几种与PML脑中所见相似的组织学异常。根据我们早期的研究结果，JCV T抗原与髓鞘基因调节蛋白的结合以及这些蛋白的功能失活可能是实验动物脑中髓鞘基因表达水平降低的原因。因此，在本研究项目中，我们提出：1）研究JCV早期蛋白，T-抗原，在没有病毒裂解感染的情况下，可能影响少突胶质细胞和星形胶质细胞功能的分子途径;和2）确定JCV早期蛋白，T-抗原，通过其与调节蛋白的结合，在神经胶质细胞的裂解性感染期间协调病毒基因表达和复制。这种全面的研究病毒的宿主相互作用在分子水平上应使我们能够了解病毒引起的中枢神经系统疾病的分子发病机制，并为我们提供关键的信息和治疗干预的生物试剂。