EPSTEIN-BARR VIRUS INDUCED GENOMIC INSTABILITY

这项研究的长期目标是了解 EB病毒（EBV）引起癌症的机制。EBV是 与鼻咽癌、地方性伯基特淋巴瘤相关 (BL)和霍奇金淋巴瘤我们认为艾滋病相关的淋巴瘤 为EBV肿瘤发生提供了新的见解，因为免疫抑制 揭示了病毒固有的特性，这些特性可能是其 病理生物学艾滋病患者EB病毒11 a缺陷型的鉴定 破坏病毒潜伏期的基因组，2/一种独特的EBV复制性损伤 (oral毛状白斑）和艾滋病相关淋巴瘤中的31种裂解抗原 都证实了这一观点的正确性。而6个核抗原和 3种膜蛋白在淋巴母细胞潜伏感染中的表达 被认为有助于EBV诱导的淋巴细胞增殖， 对于复制周期蛋白的作用还没有被认识到。我们现在 假设，作为病毒复制过程的一部分， 嗜淋巴细胞疱疹病毒激活位点特异性重组酶 免疫球蛋白和T细胞受体基因的多样化。生物 其后果包括产生具有新的缺陷的EBV基因组， 致病潜力，病毒整合到宿主基因组中，以及 引入基因组不稳定性。具体目标是测试这一点 假设是：II确定诱导表达的EBV基因产物 重组酶激活基因1和2（RAG 1和2）的表达; 2）评估重组酶激活基因1和2（RAG 1和2）的作用 V（D）J重组酶对EBV基因组结构的影响; 3）阐明EBV的致病性 EBV相关RAG表达的后果。 EBV通过病毒DNA所需基因诱导RAG表达 复制（EBNA 1和BZLF 1）将在转染试验中检查， RNA、蛋白质和功能水平（目标1）。EBV和细胞DNA 将对BL细胞中克隆的整合位点的断点进行测序 以确定V（D）J识别信号序列（RSS）的存在。EBV 将对分子间和基因内重排进行测序， V（D）J重组酶连接的标志：存在七聚体/纳米聚体RSS， 核苷酸的连接丢失和添加（目的2）。最后，利用艾滋病- 相关淋巴瘤，临床相关性将通过平行 分析单位长度和缺陷EBV DNA的整合（目的3）。 病毒DNA复制过程中V（D）J重组酶的异常表达 提供了第一个迹象表明，EBV在慢性病毒 携带者在致癌过程中有直接作用， 严重免疫抑制期间抗病毒干预的基本原理 艾滋病

The long term goal of this research is to understand the molecular mechanisms by which the Epstein-Barr virus (EBV) causes cancer. EBV is associated with nasopharyngeal carcinoma, endemic Burkitt's lymphoma (BL), and Hodgkin's lymphoma. We contend that AIDS-related lymphomas offer novel insights into EBV oncogenesis because immunosuppression unmasks properties intrinsic to the virus that may be central to its pathobiology. Identification in AIDS patients of 11 a defective EBV genome that disrupts viral latency, 2/ a unique EBV replicative lesion (oral hairy leukoplakia), and 31 lytic antigens in AIDS-related lymphomas all confirm the validity of this notion. Whereas 6 nuclear antigens and 3 membrane proteins expressed in latent infection of lymphoblastoid cells are recognized as contributing to EBV-induced lymphoproliferation, a role for replicative cycle proteins has not been appreciated. We now hypothesize that, as part of the viral replicative process, this lymphotropic herpesvirus activates site-specific recombinases involved in diversification of immunoglobulin and T cell receptor genes. Biologic consequences include generation of defective EBV genomes with novel pathogenic potential, virus integration into the host genome, and the introduction of genomic instability. Specific aims to test this hypothesis are: II determine the EBV gene product that induces expression of recombinase activating genes l and 2 (RAG1&2); 2) evaluate the effect of V(D)J recombinase on EBV genomic organization; 3) elucidate pathogenic consequences of EBV-associated RAG expression. EBV induction of RAG expression by genes required for viral DNA replication (EBNA1 and BZLF1) will be examined in transfection assays at the RNA, protein and functional levels (aim 1). EBV and cellular DNA breakpoints from cloned integration sites in BL cells will be sequenced to determine presence of V(D)J recognition signal sequences (RSS). EBV intermolecular and intragenic rearrangements will be sequenced for hallmarks of V(D)J recombinase joining: presence of heptamer/nanomer RSS, junctional loss and addition of nucleotides (aim 2). Finally, using AIDS- related lymphomas, clinical correlations will be made by parallel analyses for integration of unit length and defective EBV DNA (aim 3). Aberrant V(D)J recombinase expression during viral DNA replication would provide the first indication that EBV reactivation in chronic virus carriers has a direct role in the oncogenic process and would provide a rationale for antiviral interventions during the severe immunosuppression of AIDS.