Human immunodeficiency virus (HIV-1) remains a major health threat. Viral capsid uncoating and nuclear import of the viral genome are critical for productive infection. The size of the HIV-1 capsid is generally believed to exceed the diameter of the nuclear pore complex (NPC), indicating that capsid uncoating has to occur prior to nuclear import. Here, we combined correlative light and electron microscopy with subtomogram averaging to capture the structural status of reverse transcription-competent HIV-1 complexes in infected T cells. We demonstrated that the diameter of the NPC in cellulo is sufficient for the import of apparently intact, cone-shaped capsids. Subsequent to nuclear import, we detected disrupted and empty capsid fragments, indicating that uncoating of the replication complex occurs by breaking the capsid open, and not by disassembly into individual subunits. Our data directly visualize a key step in HIV-1 replication and enhance our mechanistic understanding of the viral life cycle.

人类免疫缺陷病毒 (HIV-1) 仍然是主要的健康威胁。病毒衣壳脱壳和病毒基因组的核输入对于生产性感染至关重要。HIV-1 衣壳的大小通常被认为超过核孔复合体 (NPC) 的直径，这表明衣壳脱壳必须在核输入之前发生。在这里，我们将相关光和电子显微镜与亚断层图平均相结合，以捕获受感染 T 细胞中具有逆转录能力的 HIV-1 复合物的结构状态。我们证明了纤维素中NPC 的直径足以进口明显完整的锥形衣壳。在核输入之后，我们检测到被破坏和空的衣壳碎片，这表明复制复合物的脱壳是通过打开衣壳而不是分解成单个亚基来发生的。我们的数据直接可视化了 HIV-1 复制的关键步骤，并增强了我们对病毒生命周期的机制理解。