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

使用 HTLV-1 编码的 Tax 剖析基因激活的基本步骤

• 批准号: 8699721
• 负责人: Alisha D Howard
• 金额: $ 5.1万
• 依托单位: COLORADO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2015-06-17
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8699721
• 关键词: Acetylation; Adult T-Cell Leukemia/Lymphoma; Affinity; Architecture; Binding; Binding Proteins; Biological Assay; CREB-binding protein; CREB1 gene; Cell physiology; Cells; Chromatin; Communities; Complex; Coupled; Cyclic AMP Response Element; Cyclic AMP-Responsive DNA-Binding Protein; DNA; Disease; Dissection; EP300 gene; Education; Event; Gene Activation; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Histone Acetylation; Histones; Human T-Cell Leukemia Viruses; Human T-lymphotropic virus 1; In Vitro; Individual; Infection; Investigation; Laboratories; Malignant - descriptor; Malignant Neoplasms; Mediating; Mutation; Nucleosomes; Oncogene Proteins; Pathway interactions; Post-Translational Protein Processing; Process; Protein Binding; Proteins; RNA Polymerase II; Recruitment Activity; Regulation; Retroviridae; Role; Site; Structure; Surface; Taxes; Training; Transcription Coactivator; Transcriptional Activation; Viral; Viral Genes; cancer type; density; design; experience; histone modification; human CREBBP protein; in vivo; interest; knowledge base; mutant; outcome forecast; promoter; public health relevance; tool

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.

描述（由申请方提供）：人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）病因相关的逆转录病毒。ATL是一种预后不良的恶性肿瘤。尽管估计有1500万至2500万人感染HTLV，但这些感染中只有2%至5%发展为ATL（综述见[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。税是 HTLV-1启动子转录的有效激活剂。Tax将细胞蛋白cAMP反应元件结合蛋白（CREB）和p300/CREB结合蛋白（CBP）募集到位于HTLV-1 LTR中的病毒CRE位点（综述见[1]）。CBP/p300参与许多细胞途径，可以理解的是，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，但其在辅激活因子介导的基因激活中的机制或作用知之甚少。我们建议CBP/p300的一个主要活动是招募一般的转录机制的启动子和税收刺激这种活动结合CBP/p300。这种结合可能引发CBP/p300不同结构域的结构变化，有利于一般转录机制的募集。总体而言，拟定研究将利用靶向点突变体、单个结构域分离和缺失的相互作用试验，靶向Tax-CBP/p300之间的相互作用。竞争和活性测定将使我们能够从功能和生物药理学上表征Tax-CBP/p300相互作用。开发的Tax和CBP/p300突变体也将用于研究CBP/p300的各个结构域中的结构变化以及这些结合诱导的变化如何与转录机器募集和活性相关。这些研究对病毒和细胞的激活机制有影响，增加了对辅激活因子在此过程中的作用的普遍薄弱的知识基础。