Dissection of a fundamental step in gene activation using the HTLV-1-encoded Tax

描述(申请人提供)：人类T细胞白血病病毒1型(HTLV-1)是一种与成人T细胞白血病(ATL)有关的逆转录病毒。ATL是一种预后较差的恶性肿瘤。尽管估计有1500万-2500万人感染HTLV，但这些感染中只有2%-5%发展为ATL(回顾见[2])。病毒表达的癌蛋白Tax是感染细胞恶性转化的主要参与者。税费是 HTLV-1启动子的有效转录激活剂。Tax将细胞蛋白cAMP反应元件结合蛋白(CREB)和p300/CREB结合蛋白(CBP)招募到位于HTLV-1 LTR中的病毒CRE位点(参见[1])。CBP/p300参与了许多细胞通路，可以理解，CBP/p300的缺陷会导致许多类型的癌症。尽管CBP/p300参与了许多细胞通路的调节，但对其在辅激活子介导的基因激活中的机制或作用知之甚少。我们认为CBP/p300的一个主要活性是向启动子招募通用转录机械，而Tax通过与CBP/p300结合来刺激这一活性。这种结合可能会在CBP/p300的不同结构域上引发结构变化，从而有利于一般转录机制的招募。总体而言，拟议的研究将利用针对Tax-CBP/p300之间相互作用的靶点突变、单个结构域分离和缺失的相互作用分析。竞争和活性分析将使我们能够从功能和生物物理上表征Tax-CBP/p300相互作用。Tax和CBP/p300突变体也将被用于研究CBP/p300各个结构域的结构变化，以及这些结合诱导的变化与转录机制招募和活性的关系。这些研究对病毒和细胞的激活机制有影响，增加了关于共激活子在这一过程中的作用的普遍薄弱的知识基础。 公共卫生相关性：人类T细胞白血病病毒1型(HTLV-1)可导致多种疾病，包括侵袭性成人T细胞白血病(ATL)。这项应用研究病毒癌蛋白TAX介导的病毒基因激活的机制。该项目有许多不同的和独特的培训机会，旨在让我在经验丰富和支持我的个人中继续深造。

DESCRIPTION (provided by applicant): The human T-cell leukemia virus type-1 (HTLV-1) is a retrovirus etiologically associated with Adult T-cell Leukemia (ATL). ATL is a malignant cancer associated with poor prognosis. Although 15-25 million people are estimated to be infected with HTLV, only 2-5 percent of these infections develop into ATL (for review see [2]). A major player in the malignant transformation of infected cells is the virally expressed oncoprotein, Tax. Tax is a potent activator of transcription from the HTLV-1 promoter. Tax recruits the cellular proteins cAMP-response element binding protein (CREB) and p300/CREB-binding protein (CBP) to viral CRE sites located in the HTLV-1 LTR (for review see [1]). CBP/p300 is involved in numerous cellular pathways and understandably, deficiencies in CBP/p300 cause many types of cancer. Despite the participation of CBP/p300 in the regulation of many cellular pathways, little is known about the mechanism or its role in coactivator-mediated gene activation. We propose that a major activity of CBP/p300 is to recruit general transcriptional machinery to the promoter and that Tax stimulates this activity by binding to CBP/p300. This binding likely initiates structural changes in distinct domains of CBP/p300 that favor recruitment of general transcriptional machinery. Overall, the proposed studies will utilize interaction assays with targeted point mutants, individual domain isolations and deletions that target the interactions between Tax-CBP/p300. Competition and activity assays will enable us to functionally and biophysically characterize Tax-CBP/p300 interactions. Tax and CBP/p300 mutants developed will also be used to investigate structural changes in various domains of CBP/p300 and how these binding- induced changes relate to transcriptional machinery recruitment and activity. These studies have implications for viral and cellular mechanisms of activation, adding to the generally weak knowledge base on the role of coactivator contribution to this process. PUBLIC HEALTH RELEVANCE: Human T-cell Leukemia virus type-1 (HTLV-1) causes several diseases including aggressive Adult T-cell Leukemia (ATL). This application investigates mechanisms of viral gene activation mediated by the viral oncoprotein, Tax. The project has many diverse and unique training opportunities designed to further my education amongst highly experienced and supportive personal.