HIV Infection of Non-Dividing Cells

描述(由申请人提供)：人类免疫缺陷病毒(HIV)和其他慢病毒感染细胞不依赖于细胞周期进展，但伽玛逆转录病毒(如小鼠白血病病毒(MLV))需要通过有丝分裂使细胞通过。以前的假设是，艾滋病毒分子的核进口特性是艾滋病毒与其他逆转录病毒之间的主要区别，其他逆转录病毒只有在有丝分裂后才进入细胞核。然而，最近的数据表明，衣壳蛋白(CA)而不是核输入蛋白是逆转录病毒感染未分裂细胞能力的主要决定因素。在这里，我们将明确地检验CA对HIV这一重要特性负有责任的模型，并将描述CA影响病毒生命周期早期事件的机制。在这项建议中，HIV-1 CA具有特定突变的HIV将以其感染未分裂细胞的能力为特征，如细胞周期停滞细胞、原代巨噬细胞和部分激活的T细胞。特别是，我们将集中在CA的N-末端区域的一组氨基酸上，初步数据表明，这些氨基酸对HIV感染未分裂细胞的能力具有深远影响。然后，我们将通过检验脱壳是未分裂细胞感染的限速步骤的假设，以及通过检查病毒核酸在未分裂细胞中的核进入是否受到影响，来确定影响这些HIV-1 CA突变体的病毒生命周期的阶段。在感染者中，许多作为艾滋病毒目标的细胞，以及被认为在传播时被感染的第一批细胞，结果证明是不增殖的。因此，HIV感染未分裂细胞的特性使其能够传播到主要的病毒库位置，如未激活的CD4+T细胞和终末分化的巨噬细胞。识别使其能够接触到非分裂细胞的精确病毒决定簇，可能会提供针对艾滋病毒的新药物靶点。

DESCRIPTION (provided by applicant): Human immunodeficiency virus (HIV) and other lentiviruses infect cells independent of cell- cycle progression, but gammaretroviruses such as the murine leukemia virus (MLV) require passage of cells through mitosis. Previously it had been hypothesized that nuclear import properties of HIV elements were the major difference between HIV and other retroviruses that only enter the nuclear after mitosis. However, recent data indicates that the capsid (CA) protein, and not nuclear import proteins, is the major determinant of the ability of a retrovirus to infect non-dividing cells. Here, we will definitively test the model that CA is responsible for this important property of HIV and we will characterize the mechanism whereby CA influences early events in the viral lifecycle. In this proposal, HIV with specific mutations in HIV-1 CA will be characterized for their ability to infect non-dividing cells such as cell-cycle arrested cells, primary macrophages, and partially activated T cells. In particular, we will concentrate on a set of amino acids in the N-terminal domain of CA that preliminary data suggest have a profound effect on the ability of HIV to infect non- dividing cells. We will then determine the stage of the virus lifecycle that is affected these HIV-1 CA mutants by testing the hypothesis that uncoating is the rate-limiting step for infection of non-dividing cells, and by examining if the nuclear entry of viral nucleic acids is affected in non-dividing cells. Many of the cells that are targets of HIV in infected people, as well as the first cells thought to be infected upon transmission, turn out to be non-proliferating. Thus, the property of HIV to infect non-dividing cells allows it to spread to major viral reservoirs sites such as non-activated CD4+ T cells and terminally differentiated macrophages. The identification of the precise viral determinants that allow it access to non-dividing cells may present new drug targets against HIV.