Functions of EBNA1 in replication & partitioning of EBV

描述（由申请方提供）：EB病毒（EBV）是一种引起传染性单核细胞增多症的人疱疹病毒。前瞻性流行病学研究表明，EBV与至少两种恶性肿瘤-地方性伯基特淋巴瘤和鼻咽癌有因果关系。EBV的基因组在所有这些疾病中是潜伏的，并且作为每个细胞周期复制一次的核附加体维持，并且在有丝分裂时有效地分配。 理解EBV附加体在每个细胞周期复制一次并被分配的机制将最终产生针对由潜伏性EBV感染引起的所有疾病的疗法。这些研究的长期目标是了解病毒游离体，特别是EBV基因组，如何保持功能状态，并具有引起人类疾病的能力。EBV基因组维持和分配所需的唯一病毒蛋白是EB核抗原1（EBNA 1），其通过其羧基末端DNA结合结构域结合称为oriP的病毒顺式元件。OriP包含两组EBNA 1- DS的结合位点，一个作为复制起点的区域，和一个当EBNA 1与其结合时作为附加体维持和分配元件的区域。我们最近发现EBNA 1的氨基末端结构域内有两个区域是AT-钩，对应于细胞蛋白质的AT-钩，例如原型AT-钩蛋白HMGA 1a。 为了证实这一观察结果，我们已经证明我们可以用HMGA 1a的AT-钩在功能上取代EBNA 1的N-末端。在本建议中，我们建议在三个方面扩展我们的研究： 1.研究EBNA 1的AT-钩区在染色体系留和附加体维持中的作用。 2.利用一种新的复制子和融合蛋白来了解EBNA 1在复制中的功能。 3.利用病毒遗传学方法研究EBNA 1在EBV诱导幼稚B细胞永生化中的作用

DESCRIPTION (provided by applicant): Epstein-Barr virus (EBV) is a human herpesvirus that causes infectious mononucleosis. Prospective epidemiologic studies indicate that EBV is causally associated with at least two malignancies - endemic Burkitt's lymphoma, and nasopharyngeal carcinoma. EBV's genome is latent in all these diseases, and is maintained as a nuclear episome that replicates once per cell cycle, and is efficiently partitioned at mitosis. Understanding the mechanism by which EBV episomes are replicated once per cell-cycle and partitioned will ultimately yield therapies against all diseases caused by a latent EBV infection. The long-range goal of these studies is to understand how viral episomes in general, but EBV genomes in specific, are maintained in a functional state with the capacity to cause human disease. The only viral protein that is required for EBV genome maintenance and partitioning is the Epstein-Barr nuclear antigen 1 (EBNA1), which binds a viral cis-element termed oriP through its carboxy-terminal DNA-binding domain. OriP contains two sets of binding sites for EBNA1 - DS, a region that serves as an origin of replication, and FR, a region that serves as an episome maintenance and partitioning element when EBNA1 is bound to it. We have recently discovered that the amino-terminal domain of EBNA1 has two regions within it that are AT-hooks, corresponding to the AT-hooks of cellular proteins such as the prototypic AT-hook protein HMGA1a. Confirming this observation, we have demonstrated that we can functionally replace the N-terminus of EBNA1 with the AT-hooks of HMGA1a. In this proposal we propose to extend our studies in three areas: 1. To characterize the roles of the AT-hook regions of EBNA1 in chromosome tethering and episome maintenance. 2. To utilize a novel replicon and fusion protein to understand the function of EBNA1 in replication. 3. To use viral genetics to determine the functions of EBNA1 in the immortalization of naive B-cells by EBV