MECHANISMS OF MUTATIONS & HYPERMUTATIONS IN RETROVIRUSES

突变机制

• 批准号: 3460679
• 负责人: VINAY K. PATHAK
• 金额: $ 10.15万
• 依托单位: WEST VIRGINIA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-01 至 1997-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3460679
• 关键词: 2'3' dideoxycytidine; 2'3' dideoxyinosine; DNA replication; RNA directed DNA polymerase; Retroviridae; biological models; chickens; drug resistance; gene mutation; mutant; virus genetics; virus replication; zidovudine

DESCRIPTION (Adapted from the applicant's abstract): The goal of this project is to understand the molecular and biological mechanisms that generate variation in retroviral populations.Variation in retroviral populations has become medically important because it generates drug- resistant human immuno-deficiency (HIV) variants, allows the virus to evade the host immune response, and may frustrate efforts to develop anti-retroviral vaccines. Mutations in retroviruses are also essential for activating the oncogenic potential of proto-oncogenes captured by retroviruses. A clinically relevant aim is to use the spleen necrosis virus (SNV)-based in vivo forward mutation assay to determine whether anti-retroviral drugs AZT, ddI and ddC increase the retroviral mutation rate and contribute to the generation of drug-resistant virus. A related aim is to select for drug-resistant SNV and determine whether the mutant reverse transcriptases have altered mutation rates. Virus producing cells or target cells will be exposed to the drugs to determine whether they are mutagenic during viral RNA transcription or reverse transcription. SNV vectors will be designed to distinguish spontaneous as well as drug- induced mutations during RNA- or DNA-dependent DNA synthesis stages of reverse transcription. A second aim is to further understand the process we named hypermutation, in which several mutations occur in each provirus during one round of retroviral replication. The frequency and types of hypermutation will be determined by using retroviral vectors designed to identify hypermutation. Our hypothesis that hypermutation results from polymerization by error-prone reverse transcriptases will be tested by utilizing a retroviral vector designed to identify and isolate genes encoding hypermutant reverse transcriptases. A third aim is to perform the forward mutation assay in an animal model system to determine the mutation rates in a single replication cycle, determine the replication rate for SNV in various stages of infection, and determine the relative replication rate for a wildtype and defective virus in co-infected animals to determine the evolutionary potential of retroviruses with transduced oncogenes.

描述(改编自申请人的摘要)：本报告的目标 这个项目是为了了解分子和生物机制 在逆转录病毒种群中产生变异。逆转录病毒变异 人口在医学上已经变得很重要，因为它会产生药物- 抗药性人类免疫缺陷(HIV)变种，使病毒能够 逃避宿主的免疫反应，并可能挫败发展的努力 抗逆转录病毒疫苗。逆转录病毒的突变也是必不可少的。 激活原癌基因的致癌潜能 逆转录病毒。 临床上相关的目的是使用以脾坏死病毒(SNV)为基础的 体内正向突变试验确定抗逆转录病毒药物 AZT、ddi和ddC可增加逆转录病毒突变率，并有助于 抗药性病毒的产生。一个相关的目标是选择 抗药性SNV并确定突变株是否逆转 转录酶改变了突变率。病毒产生细胞或 靶细胞将暴露在药物中以确定它们是否 在病毒RNA转录或逆转录过程中会发生突变。SNV 载体将被设计来区分自发性和药物- 在依赖RNA或DNA的DNA合成阶段诱导突变 逆转录。 第二个目标是进一步了解我们称之为超突变的过程， 其中每个前病毒在一轮前病毒中发生几个突变 逆转录病毒复制。超突变的频率和类型将 通过使用逆转录病毒载体来确定 超突变。我们的假设是超突变是由 容易出错的逆转录酶的聚合将通过 利用逆转录病毒载体鉴定和分离基因 编码超突变逆转录酶。 第三个目标是在动物模型中进行正向突变分析 系统来确定单个复制周期中的突变率， 确定SNV在感染的不同阶段的复制率， 并确定野生型和缺陷的相对复制率 共同感染动物体内的病毒以确定其进化潜力 转导癌基因的逆转录病毒。