MECHANISMS OF MUTATIONS & HYPERMUTATIONS IN RETROVIRUSES

描述（改编自申请人的摘要）：本研究的目标 项目是了解分子和生物学机制， 在逆转录病毒群体中产生变异。 人口在医学上变得重要，因为它产生药物- 抗人类免疫缺陷病毒（HIV）变种，使病毒， 逃避宿主的免疫反应，并可能挫败发展 抗逆转录病毒疫苗。逆转录病毒的突变也是必不可少的 用于激活被捕获的原癌基因的致癌潜力， 逆转录病毒 临床相关的目的是使用基于脾坏死病毒（SNV）的 体内正向突变试验，以确定抗逆转录病毒药物 AZT、ddI和ddC会增加逆转录病毒突变率， 抗药性病毒的产生。 一个相关的目标是选择 耐药SNV，并确定突变是否逆转 转录酶具有改变的突变率。 病毒产生细胞或 靶细胞将暴露于药物，以确定它们是否 在病毒RNA转录或逆转录过程中具有诱变性。 SNV 载体将被设计为区分自发性和药物性， 在RNA或DNA依赖的DNA合成阶段诱导突变， 逆转录 第二个目标是进一步理解我们命名为超突变的过程， 其中在一轮病毒感染期间，每个原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 通过使用逆转录病毒载体确定， 超突变 我们假设超突变是由 通过易错逆转录酶的聚合将被测试， 利用逆转录病毒载体， 编码超突变逆转录酶。 第三个目的是在动物模型中进行正向突变测定 系统来确定单个复制周期中的突变率， 确定SNV在不同感染阶段的复制率， 并确定野生型和缺陷型的相对复制率 病毒在共感染动物，以确定进化潜力 逆转录病毒与转导的致癌基因。

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.