Regulation of the Epstein-Barr Virus Lytic Switch

摘要 爱泼斯坦-巴尔病毒(EBV)在全球95%的成年人中建立终身感染。EB病毒 导致传染性单核细胞增多症、淋巴瘤、鼻咽癌和胃癌以及口腔癌 毛状白斑。EBV通过唾液在宿主之间传播，并从唾液移位 穿过口腔和扁桃体上皮到达B细胞室。在B细胞上 感染后，~170kb的线性双链DNA(DsDNA)EBV基因组被传递到 原子核。然后，EBV使用一系列延迟程序来导航B细胞隔间， 并在记忆B细胞室定植。最终，在细胞之间传播，并传播到 扁桃体上皮细胞要转移到新的宿主，EBV必须经历裂解复制，在其中 表达了近80种病毒蛋白，并产生了具有感染性的病毒粒子。裂解复制是 越来越多地与肿瘤发生有关。然而，关于病毒是如何 裂解开关被控制。因此，我们使用了全人类基因组CRISPR/Cas9筛查 确定控制病毒裂解开关的宿主因素。我们分析了一个主机因素网络， 抑制裂解再激活，以转录因子MYC为中心，包括粘附素，FACT， STAGA和Mediator。MYC或对MYC表达重要的因子的耗尽，重新激活 裂解周期，包括Burkitt异种移植物。裂解细胞与EBV基因组起源的结合 复制并抑制其与裂解环启动子BZLF1启动子的环路。我们的中央 假设MYC：MAX通过调节病毒基因组来控制EBV的裂解开关 环拉伸。我们的目标是(1)确定在oriLyt环挤出调节中的关键MYC角色，以 控制EBV裂解开关；(2)确定MYC门控粘附素在oriLyt环调控中的作用 EBV裂解开关控制中的挤出(3)确定MYC门控CTCF在oriLyt调控中的作用 环状挤压以控制EBV裂解开关。总体而言，这些研究有望确定 EBV如何颠覆宿主DNA环挤出途径以控制病毒裂解开关。 因此，我们的研究可能支持开发合理的溶解诱导治疗的策略。 EB病毒相关疾病的治疗方法。

Abstract Epstein-Barr virus (EBV) establishes lifelong infection in 95% of adults worldwide. EBV causes infectious mononucleosis, lymphomas, nasopharyngeal and gastric cancer, and oral hairy leukoplakia. EBV is transmitted between hosts through saliva, from which it translocates across the oral cavity and tonsillar epithelium to reach the B-cell compartment. Upon B-cell infection, the ~170 kilobase linear double-stranded DNA (dsDNA) EBV genome is delivered to the nucleus. EBV then uses a series of latency programs to navigate the B-cell compartment, and colonize the memory B-cell compartment. Ultimately, to spread between cells and to the tonsillar epithelium for transfer to a new host, EBV must undergo lytic replication, in which nearly 80 viral proteins are expressed and infectious virion are produced. Lytic replication is increasingly implicated in oncogenesis. Yet, much remains to be learned about how the viral lytic switch is controlled. We therefore used a human genome-wide CRISPR/Cas9 screen to identify host factors that control the viral lytic switch. Our analyses a network of host factors that repress lytic reactivation, centered on the transcription factor MYC, including cohesins, FACT, STAGA, and Mediator. Depletion of MYC or factors important for MYC expression, reactivated the lytic cycle, including in Burkitt xenografts. MYC bound the EBV genome origin of lytic replication and suppressed its looping to the lytic cycle initiator BZLF1 promoter. Our central hypothesis is that the MYC:MAX control the EBV lytic switch through regulation of viral genome loop extrusion. Our Aims are to (1) Define key MYC roles in regulation of oriLyt loop extrusion to control the EBV lytic switch; (2) Define MYC-gated cohesin roles in regulation of oriLyt loop extrusion in EBV lytic switch control (3) Define MYC-gated CTCF roles in regulation of oriLyt loop extrusion to control the EBV lytic switch. Collectively, these studies are expected to identify how EBV subverts host DNA loop extrusion pathways to control the viral lytic switch. Our studies may therefore support strategies to develop rational lytic induction therapeutic therapies for EBV-associated diseases.