A critical role for alternative polyadenylation factor CPSF6 in targeting HIV-1 integration to transcriptionally active chromatin
A critical role for alternative polyadenylation factor CPSF6 in targeting HIV-1 integration to transcriptionally active chromatin
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DOI：
10.1073/pnas.1524213113
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发表时间：
2016-02-23
影响因子：
11.1
通讯作者：
Engelman, Alan N.
中科院分区：
文献类型：
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作者：
Sowd, Gregory A.;Serrao, Erik;Engelman, Alan N.
整合对于逆转录病毒复制至关重要，并影响潜伏 HIV 病毒库的建立。 HIV-1 整合有利于活性基因，这部分是由整合酶和晶状体上皮衍生生长因子 (LEDGF)/p75 之间的相互作用决定的。由于相对于 LEDGF/p75 缺陷细胞中的随机而言，基因靶向仍然显着富集，因此其他宿主因素可能有助于基因趋向性整合。核孔蛋白 153 和 358 与 HIV-1 衣壳结合，在整合靶向中发挥相对较小的作用，但另一种衣壳结合蛋白、切割和聚腺苷酸化特异性因子 6 (CPSF6) 的影响尚未报道。在这项研究中，我们与 LEDGF/p75 并行或串联地敲低或敲除 CPSF6。 CPSF6敲除改变了病毒感染动力学，减少了原病毒形成，并优先减少了与转录活性基因、剪接基因和富含基因并激活组蛋白修饰的染色质区域的整合。相比之下，LEDGF/p75 耗尽优先改变基因体内的位置整合靶向。双因子敲除将基因整合降低至低于任一单基因敲除观察到的水平，并揭示 CPSF6 在指导常染色质整合方面比 LEDGF/p75 发挥着更主导的作用。 CPSF6 互补可以挽救 CPSF6 敲除细胞中的 HIV-1 整合位点分布，但与 CPSF6 衣壳结合突变体的互补则不能。我们得出结论，整合靶向通过两种不同的机制进行：衣壳-CPSF6结合引导HIV-1主动转录的常染色质，其中整合酶-LEDGF/p75相互作用驱动整合到基因体中。
Integration is vital to retroviral replication and influences the establishment of the latent HIV reservoir. HIV-1 integration favors active genes, which is in part determined by the interaction between integrase and lens epithelium-derived growth factor (LEDGF)/p75. Because gene targeting remains significantly enriched, relative to random in LEDGF/p75 deficient cells, other host factors likely contribute to gene-tropic integration. Nucleoporins 153 and 358, which bind HIV-1 capsid, play comparatively minor roles in integration targeting, but the influence of another capsid binding protein, cleavage and polyadenylation specificity factor 6 (CPSF6), has not been reported. In this study we knocked down or knocked out CPSF6 in parallel or in tandem with LEDGF/p75. CPSF6 knockout changed viral infectivity kinetics, decreased proviral formation, and preferentially decreased integration into transcriptionally active genes, spliced genes, and regions of chromatin enriched in genes and activating histone modifications. LEDGF/p75 depletion by contrast preferentially altered positional integration targeting within gene bodies. Dual factor knockout reduced integration into genes to below the levels observed with either single knockout and revealed that CPSF6 played a more dominant role than LEDGF/p75 in directing integration to euchromatin. CPSF6 complementation rescued HIV-1 integration site distribution in CPSF6 knockout cells, but complementation with a capsid binding mutant of CPSF6 did not. We conclude that integration targeting proceeds via two distinct mechanisms: capsid-CPSF6 binding directs HIV-1 to actively transcribed euchromatin, where the integrase-LEDGF/p75 interaction drives integration into gene bodies.