Cells derived from mice and other rodents exhibit profound blocks to HIV-1 virion production, reflecting species-specific incompatibilities between viral Tat and Rev proteins and essential host factors cyclin T1 (CCNT1) and exportin-1 (XPO1, also known as CRM1), respectively. To determine if mouse cell blocks other than CCNT1 and XPO1 affect HIV's postintegration stages, we studied HIV-1_NL4-3 gene expression in mouse NIH 3T3 cells modified to constitutively express HIV-1-compatible versions of CCNT1 and XPO1 (3T3.CX cells). 3T3.CX cells supported both Rev-independent and Rev-dependent viral gene expression and produced relatively robust levels of virus particles, confirming that CCNT1 and XPO1 represent the predominant blocks to these stages. Unexpectedly, however, 3T3.CX cells were remarkably resistant to virus-induced cytopathic effects observed in human cell lines, which we mapped to the viral protein Vif and its apparent species-specific capacity to induce G₂/M cell cycle arrest. Vif was able to mediate rapid degradation of human APOBEC3G and the PPP2R5D regulatory B56 subunit of the PP2A phosphatase holoenzyme in mouse cells, thus demonstrating that Vif_NL4-3's modulation of the cell cycle can be functionally uncoupled from some of its other defined roles in CUL5-dependent protein degradation. Vif was also unable to induce G₂/M cell cycle arrest in other nonhuman cell types, including cells derived from nonhuman primates, leading us to propose that one or more human-specific cofactors underpin Vif's ability to modulate the cell cycle.

IMPORTANCE Cells derived from mice and other rodents exhibit profound blocks to HIV-1 replication, thus hindering the development of a low-cost small-animal model for studying HIV/AIDS. Here, we engineered otherwise-nonpermissive mouse cells to express HIV-1-compatible versions of two species-specific host dependency factors, cyclin T1 (CCNT1) and exportin-1 (XPO1) (3T3.CX cells). We show that 3T3.CX cells rescue HIV-1 particle production but, unexpectedly, are completely resistant to virus-induced cytopathic effects. We mapped these effects to the viral accessory protein Vif, which induces a prolonged G₂/M cell cycle arrest followed by apoptosis in human cells. Combined, our results indicate that one or more additional human-specific cofactors govern HIV-1's capacity to modulate the cell cycle, with potential relevance to viral pathogenesis in people and existing animal models.

来自小鼠和其他啮齿动物的细胞对 HIV-1 病毒颗粒的产生表现出严重的阻碍，反映了病毒 Tat 和 Rev 蛋白与重要宿主因子细胞周期蛋白 T1 (CCNT1) 和输出蛋白-1 (XPO1，也称为 CRM1) 之间的物种特异性不相容性，分别。为了确定除 CCNT1 和 XPO1 之外的小鼠细胞阻断是否会影响 HIV 的整合后阶段，我们研究了小鼠 NIH 3T3 细胞中的 HIV-1 _NL4-3基因表达，这些细胞经过修饰以组成型表达 HIV-1 兼容版本的 CCNT1 和 XPO1（3T3.CX 细胞） ）。 3T3.CX 细胞支持 Rev 独立和 Rev 依赖性病毒基因表达，并产生相对稳定水平的病毒颗粒，证实 CCNT1 和 XPO1 代表了这些阶段的主要阻断。然而，出乎意料的是，3T3.CX 细胞对在人类细胞系中观察到的病毒诱导的细胞病变效应具有显着的抵抗力，我们将其映射到病毒蛋白 Vif 及其诱导 G ₂ /M 细胞周期停滞的明显物种特异性能力。 Vif 能够介导小鼠细胞中人 APOBEC3G 和 PP2A 磷酸酶全酶的 PPP2R5D 调节 B56 亚基的快速降解，从而证明 Vif _NL4-3对细胞周期的调节可以在功能上与其其他一些定义的作用脱钩参与 CUL5 依赖性蛋白质降解。 Vif 也无法在其他非人类细胞类型（包括源自非人类灵长类动物的细胞）中诱导 G ₂ /M 细胞周期停滞，这使我们提出一种或多种人类特异性辅因子支撑 Vif 调节细胞周期的能力。

重要性来自小鼠和其他啮齿动物的细胞对 HIV-1 复制表现出显着的阻断作用，从而阻碍了用于研究 HIV/艾滋病的低成本小动物模型的开发。在这里，我们对原本不允许的小鼠细胞进行了改造，以表达两种物种特异性宿主依赖性因子的 HIV-1 兼容版本：细胞周期蛋白 T1 (CCNT1) 和输出蛋白-1 (XPO1)（3T3.CX 细胞）。我们发现 3T3.CX 细胞可以挽救 HIV-1 颗粒的产生，但出乎意料的是，它完全抵抗病毒诱导的细胞病变效应。我们将这些效应映射到病毒辅助蛋白 Vif 上，该蛋白可诱导延长的 G ₂ /M 细胞周期停滞，随后导致人类细胞凋亡。综合起来，我们的结果表明，一种或多种额外的人类特异性辅因子控制着 HIV-1 调节细胞周期的能力，与人类和现有动物模型中的病毒发病机制具有潜在相关性。