Fundamental Microbiology and Pathogenicity Lab (MFP), UMR 5234 CNRS-University of Bordeaux, SFR TransBioMed. Bordeaux, France.
Imaging and modeling unit, Computational Biology Department, Institut Pasteur, Paris, France.
Nucleic Acids Res. 2021 Nov 8;49(19):11241-11256. doi: 10.1093/nar/gkab886.
The stable insertion of the retroviral genome into the host chromosomes requires the association between integration complexes and cellular chromatin via the interaction between retroviral integrase and the nucleosomal target DNA. This final association may involve the chromatin-binding properties of both the retroviral integrase and its cellular cofactor LEDGF/p75. To investigate this and better understand the LEDGF/p75-mediated chromatin tethering of HIV-1 integrase, we used a combination of biochemical and chromosome-binding assays. Our study revealed that retroviral integrase has an intrinsic ability to bind and recognize specific chromatin regions in metaphase even in the absence of its cofactor. Furthermore, this integrase chromatin-binding property was modulated by the interaction with its cofactor LEDGF/p75, which redirected the enzyme to alternative chromosome regions. We also better determined the chromatin features recognized by each partner alone or within the functional intasome, as well as the chronology of efficient LEDGF/p75-mediated targeting of HIV-1 integrase to chromatin. Our data support a new chromatin-binding function of integrase acting in concert with LEDGF/p75 for the optimal association with the nucleosomal substrate. This work also provides additional information about the behavior of retroviral integration complexes in metaphase chromatin and the mechanism of action of LEDGF/p75 in this specific context.
逆转录病毒基因组的稳定插入宿主染色体需要整合复合物与细胞染色质通过逆转录酶与核小体靶 DNA 之间的相互作用进行关联。这种最终的关联可能涉及逆转录酶及其细胞辅助因子 LEDGF/p75 的染色质结合特性。为了研究这一点并更好地了解 LEDGF/p75 介导的 HIV-1 整合酶染色质固定，我们使用了生化和染色体结合测定的组合。我们的研究表明，逆转录酶具有内在的结合和识别中期特定染色质区域的能力，即使在没有其辅助因子的情况下也是如此。此外，这种整合酶染色质结合特性受到与其辅助因子 LEDGF/p75 的相互作用的调节，该相互作用将酶重新导向替代的染色体区域。我们还更好地确定了每个伴侣单独或在功能性整合酶中识别的染色质特征，以及 HIV-1 整合酶与染色质的有效 LEDGF/p75 介导靶向的时间顺序。我们的数据支持整合酶与 LEDGF/p75 协同作用的新染色质结合功能，以与核小体底物最佳结合。这项工作还提供了关于逆转录病毒整合复合物在中期染色质中的行为以及 LEDGF/p75 在这种特定环境中的作用机制的更多信息。
