Compensating Tat/TAR mutations in drug-resistant HIV-1

描述（由申请方提供）：抗逆转录病毒疗法（ART）靶向在病毒产生中具有活性的CD 4 + T细胞中的HIV-1复制。尽管ART可以将病毒载量降低到无法检测的水平，但仍会选择一小群耐药病毒基因组，并在药物存在下继续复制。在这一人群中，抗逆转录病毒治疗的分子靶点逆转录酶（RT）和蛋白酶（PR）积累了导致耐药性的突变。同时，这些耐药突变是有害的，降低了RT和PR的活性，并导致具有较低复制能力的病毒的持续存在（即，较小的“适应性”）。持续的病毒进化选择补偿突变，导致更适合的病毒出现。RT和PR基因中的这种突变已经得到了很好的表征，但也有迹象表明，补偿突变可能出现在其他病毒基因中。 一个这样的候选基因是必需的病毒转录激活因子，达特。我们和其他人已经确定了增加病毒基因表达的天然达特突变。我们假设，在达特或其病毒靶点TAR中具有突变的病毒增加了多药耐药病毒的适应性，并将被选择存活。在这个探索性的项目中，我们建议解决的假设，即达特和/或TAR变异体的更高的效力选择在ART。我们将测试的健身病毒含有这些选定的达特和/或TAR变异体的耐药突变的背景下，在RT和PR，随后的实验将解决潜在的生化机制。 在此期间，我们的目标将是： 1.目的对HIV-1耐药株的达特基因及其TAR元件进行序列测定和分析。 2.表征所选达特和TAR变体的复制适应性和功能。

DESCRIPTION (provided by applicant): Anti-Retroviral Therapy (ART) targets HIV-1 replication in CD4+ T cells that are active in virus production. Although ART can reduce the viral load to undetectable levels, a small population of drug-resistant viral genomes is selected and continues to replicate in the presence of the drugs. In this population, the molecular targets of antiretroviral therapy, reverse transcriptase (RT) and protease (PR), accumulate mutations that confer drug resistance. At the same time these drug-resistance mutations are deleterious, reducing the activity of RT and PR and resulting in the persistence of viruses that have lower replicative capacity (i.e., lesser "fitness"). Continuing viral evolution selects for compensating mutations resulting in the emergence of viruses that are fitter. Such mutations in the RT and PR genes are well characterized, but there are also indications that compensating mutations can arise in other viral genes. One such candidate gene is the essential viral transcription activator, Tat. We and others have identified natural Tat mutations that increase viral gene expression. We postulate that viruses with mutations in Tat, or in its viral target TAR, increase the fitness of multidrug-resistant viruses and will be selected for survival. In this exploratory project we propose to address the hypothesis that Tat and/or TAR variants of higher potency are selected during ART. We will test the fitness of viruses containing these selected Tat and/or TAR variants in the context of drug-resistance mutations in RT and PR, and subsequent experiments will address the underlying biochemical mechanisms. During the term of this grant our aims will be: 1. To sequence and analyze HIV-1 Tat genes and the TAR element of viruses isolated from HIV-1 drug-resistant patients. 2. To characterize the replicative fitness and function of selected Tat and TAR variants.