Capsid-CPSF6 interaction as opposed to nuclear architecture dictates intranuclear HIV-1 localization and integration site selection

Image-based studies suggest nuclear architecture dictates HIV-1 integration site selection. Here we investigated the early phase of HIV-1 infection in transformed and primary cells using multiple orthologous approaches including viral imaging, integration site mapping, and intranuclear localization of preferred gene targets. Our multimodal approach demonstrates that under normal infection conditions, HIV-1 disperses throughout the nucleus for integration into transcriptionally active gene-dense regions. Loss of interaction with the viral capsid host cofactor cleavage and polyadenylation specificity factor 6 (CPSF6), however, dramatically altered virus localization towards the nuclear periphery and integration into transcriptionally inactive lamina-associated heterochromatin. By contrast, the integrase-binding cofactor lens epithelium-derived growth factor/p75 did not play a significant role in HIV-1 intranuclear localization. We conclude that the CPSF6-capsid interaction, and not nuclear architecture, plays a dominant role in viral intranuclear trafficking. CPSF6 directs HIV-1 preintegration complexes away from heterochromatin at the nuclear periphery towards gene-dense euchromatin located throughout the nucleus.

基于成像的研究表明，核结构决定HIV-1的整合位点选择。本研究针对转化细胞与原代细胞中的HIV-1感染早期阶段，采用病毒成像、整合位点图谱分析、偏好基因靶点核内定位等多种同源实验方法开展研究。我们的多模态研究结果显示，在正常感染条件下，HIV-1会在细胞核内弥散分布，进而整合至转录活跃的基因密集区域。然而，当病毒衣壳与宿主辅助因子剪切与多聚腺苷酸化特异性因子6（CPSF6）的相互作用丧失后，病毒的核内定位会显著向核周区域偏移，并整合至转录沉默的核纤层关联异染色质中。与之形成对比的是，整合酶结合辅助因子晶状体上皮来源生长因子/p75并未对HIV-1的核内定位产生显著影响。综上，我们认为在病毒核内运输过程中起主导作用的是CPSF6与衣壳的相互作用，而非核结构。CPSF6可引导HIV-1预整合复合物远离核周的异染色质，向遍布细胞核的基因密集常染色质区域迁移。