Control of Papillomavirus Expression and Transformation

描述（由申请人提供）：E2蛋白作为稳定的附加体调节乳头瘤病毒基因组的转录和复制。其N-末端结构域结合这些功能所必需的细胞因子和复合物。这些细胞蛋白通过E2 C-末端结构域靶向病毒基因组，其以高亲和力结合病毒DNA中的特定序列。这项资助提案的目标是鉴定和表征E2启动其多种功能的细胞蛋白质和途径。第一个目的是研究E2在细胞周期中的活动，当E2将病毒E1 DNA解旋酶定位到S期的起点时，以及在有丝分裂中当E2将病毒基因组拴在宿主染色体上时，介导其分配，并且正如我们在这里提出的，废除可能限制宿主细胞活力的有丝分裂检查点。我们证明了E2与几种有丝分裂蛋白的相互作用，这些蛋白将在本目标中进一步表征。这些蛋白质-蛋白质相互作用揭示了病毒基因组在有丝分裂过程中附着于染色体的新机制。其他的相互作用表明了一种在有丝分裂纺锤体上运输病毒基因组的机制。该目的的另一个目标是研究E2抑制有丝分裂检查点的能力。在一个例子中，我们测试的假设，E2抑制胞质分裂，功能可能是必要的病毒基因组扩增分化上皮细胞。病毒基因组整合后E2功能的丧失和E2的破坏可能是致癌性人乳头瘤病毒肿瘤进展的重要步骤。目的2继续我们的调查机制的转录调控，特别强调如何E2克服染色质抑制在体内。我们测试的假设，E2与Swi/Snf染色质重塑复合物的组件的相互作用是必要的转录激活和抑制。这些研究将拓宽我们对E2在病毒复制程序中的分子功能的理解。 外行声明：乳头瘤病毒引起的良性感染，可以成为恶性，是宫颈癌的病原体。E2蛋白控制病毒的基本功能。我们建议确定细胞中与E2相互作用的蛋白质及其功能。这些参与了包括基因表达和DNA复制在内的基本过程。了解E2如何运作将提供对这些途径的生物学的见解，并推断导致癌症发展的畸变可能如何发生。

DESCRIPTION (provided by applicant): The E2 protein regulates transcription and replication of the papillomavirus genome as a stable episome. Its N-terminal domain binds cellular factors and complexes necessary for these functions. These cellular proteins are targeted to the viral genome by the E2 C-terminal domain, which binds with high affinity to specific sequences in the viral DNA. The goal of this grant proposal is to identify and characterize the cellular proteins and pathways through which E2 actuates its diverse functions. The first Aim investigates the activities of E2 during cell cycle, when E2 localizes the viral E1 DNA helicase to the origin in S phase, and in mitosis when E2 tethers the viral genome to host chromosomes, mediates its partitioning, and as we propose here, abrogates mitotic checkpoints that might otherwise restrict host cell viability. We demonstrate E2 interactions with several mitotic proteins that will be further characterized in this Aim. These protein- protein interactions reveal novel mechanisms for viral genome attachment to chromosomes during mitosis. Other interactions suggest a mechanism to transport the viral genome on the mitotic spindle. Another goal of this aim is to investigate the ability of E2 to inhibit mitotic checkpoints. In one example, we test the hypothesis that E2 inhibits cytokinesis, a function that is probably necessary for viral genome amplification in differentiated epithelial cells. Loss of these E2 functions following viral genome integration and disruption of E2 may represent an important step in neoplastic progression by oncogenic human papillomaviruses. Aim 2 continues our investigations of the mechanism of transcriptional regulation, with particular emphasis on how E2 overcomes chromatin repression in vivo. We test the hypothesis that E2 interactions with components of the Swi/Snf chromatin-remodeling complex are necessary for transcriptional activation and repression. These studies will broaden our understanding of the molecular functions of E2 in the viral replicative program. Lay Statement: Papillomaviruses cause benign infections that can become malignant, and are the etiologic agent of cervical cancer. The E2 protein controls essential functions of the virus. We propose to identify the proteins in the cell that interact with E2 and their functions. These are involved in fundamental process including gene expression and DNA replication. Understanding how E2 operates will provide insights into the biology of these pathways and infer how aberrations may occur that lead to the development of cancer.