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程，但γ逆转录病毒如鼠白血病病毒（MLV）需要细胞通过有丝分裂。以前，人们假设HIV元件的核输入特性是HIV与其他逆转录病毒之间的主要区别，这些逆转录病毒仅在有丝分裂后进入核。然而，最近的数据表明，衣壳（CA）蛋白，而不是核输入蛋白，是逆转录病毒感染非分裂细胞的能力的主要决定因素。在这里，我们将明确测试CA负责HIV的这一重要特性的模型，我们将描述CA影响病毒生命周期早期事件的机制。在该提案中，在HIV-1 CA中具有特定突变的HIV将表征其感染非分裂细胞如细胞周期停滞细胞、原代巨噬细胞和部分活化的T细胞的能力。特别地，我们将集中于CA的N-末端结构域中的一组氨基酸，初步数据表明其对HIV感染非分裂细胞的能力具有深远的影响。然后，我们将确定病毒生命周期的阶段，这些HIV-1 CA突变体的影响，通过测试的假设，即脱壳是非分裂细胞感染的限速步骤，并通过检查，如果病毒核酸的核进入非分裂细胞的影响。在感染者体内，许多作为艾滋病毒靶点的细胞，以及被认为在传播时被感染的第一批细胞，都是非增殖性的。因此，HIV感染非分裂细胞的特性允许其扩散到主要的病毒储库位点，如非活化的CD 4 + T细胞和终末分化的巨噬细胞。确定精确的病毒决定因素，使其能够进入非分裂细胞，可能会提出新的药物靶点对抗艾滋病毒。

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.