Biology of the Epstein-Barr Virus R Transactivator in Human B Cells

爱泼斯坦-巴尔病毒(Epstein-Barr Virus，EBV)是一种人类肿瘤病毒，在病原学上与鼻咽癌和 胃癌、伯基特氏、霍奇金和免疫母细胞性淋巴瘤等人类癌症。在所有关联的EBV中 在肿瘤和正常的B细胞中，病毒仍然处于基因表达受限的潜伏状态。这个 病毒必须重新激活进入裂解周期，才能在细胞之间和个体之间传播。这个 编码在病毒BRLF1基因中的EBV/RTA蛋白在介导病毒与病毒之间的转换中起着不可或缺的作用 潜伏期和裂解周期基因的表达，既作为转录因子又作为复制蛋白。RTA是 因此，它在发病机制和肿瘤发生中起着关键作用。我们的全球目标是了解对 BRLF1的表达，RTA的作用机制以及RTA可能调控表达和 细胞蛋白质的定位。拟议的实验源自许多最新的出版物和 研究EBV/RTA表达和活性调控的广泛初步数据和 其同源基因KSHV/ORF50。我们将解开未解之谜：哪些细胞蛋白调节 RTA的表达？为什么一些细胞对裂解诱导刺激的反应是通过RTA的表达，而另一些细胞则是通过表达RTA 是难熬的吗？RTA是如何同时作为转录因子和复制蛋白发挥作用的？RTA如何 改变关键细胞蛋白的功能和定位？因此，我们的具体目标是：1)确定 细胞即刻早期蛋白的能力和重要性，如早期反应和孤儿核 2)为了了解RTA在EB病毒DNA复制中的作用， 特别是磷酸化和DNA结合调节的作用；以及3)描述RTA的功能 DNA损伤反应粘附素、SMC1、STAT3和PolyA的表达、激活和再定位 结合蛋白。建议的研究，利用细胞生物学、生物化学、分子遗传学和 免疫学涉及控制真核基因表达的两个基本问题，这些问题与 癌症和一种重要的人类癌症病毒分子发病机制的特定悬而未决的问题 目前还没有具体的预防或治疗方法。

Epstein-Barr virus (EBV) is a human tumor virus that is etiologically associated with nasopharyngeal and gastric cancer, Burkitt's, Hodgkin's and immunoblastic lymphoma and other human cancers. In all EBVassociated tumors and in normal B cells, the virus remains in a latent state of limited gene expression. The virus must be reactivated into its lytic cycle in order to spread between cells and among individuals. The EBV/Rta protein encoded in the viral BRLF1 gene plays an obligatory role in mediating the switch between latency and lytic cycle gene expression, acting both as a transcription factor and a replication protein. Rta is thus is a key factor in pathogenesis and oncogenesis. Our global objectives are to understand the control of BRLF1 expression, the mechanism of action of Rta and the ways Rta might manipulate expression and localization of cellular proteins. The proposed experiments are derived from many recent publications and extensive preliminary data that investigated control of expression and regulation of activity of EBV/Rta and its homologue KSHV/ORF50. We will address unsolved mysteries: Which cellular proteins regulate expression of Rta? Why do some cells respond to lytic inducing stimuli by expression of Rta while other cells are refractory? How does Rta function both as a transcription factor and replication protein? How does Rta alter the function and localization of key cellular proteins? Accordingly, our specific aims are 1) To determine the capacity and importance of cellular immediate-early proteins, such as early response and orphan nuclear receptor proteins, to activate Rta expression; 2) To understand the function of Rta in EBV DNA replication, particularly the role of phosphorylation and regulation of DNA binding; and 3) To delineate the function of Rta in expression, activation and re-Iocalization of the DNA damage response cohesin, SMC1, STAT3 and PolyA binding protein. The proposed studies, utilizing tools of cell biology, biochemistry, molecular genetics, and immunology address both basic questions of control of eukaryotic gene expression that are relevant to cancer and specific unresolved issues about molecular pathogenesis of an important human cancer virus for which there is yet no specific prevention or treatment.