Ouasti Fouad, Audin Maxime, Fréon Karine, Quivy Jean-Pierre, Tachekort Mehdi, Cesard Elizabeth, Thureau Aurélien, Ropars Virginie, Fernández Varela Paloma, Moal Gwenaelle, Soumana-Amadou Ibrahim, Uryga Aleksandra, Legrand Pierre, Andreani Jessica, Guerois Raphaël, Almouzni Geneviève, Lambert Sarah, Ochsenbein Francoise
Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, Gif-sur-Yvette, France.
Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Université Paris-Saclay, Equipe labellisée Ligue contre le Cancer, Orsay, France.
Elife. 2024 Feb 20;12:RP91461. doi: 10.7554/eLife.91461.
Genome and epigenome integrity in eukaryotes depends on the proper coupling of histone deposition with DNA synthesis. This process relies on the evolutionary conserved histone chaperone CAF-1 for which the links between structure and functions are still a puzzle. While studies of the CAF-1 complex enabled to propose a model for the histone deposition mechanism, we still lack a framework to demonstrate its generality and in particular, how its interaction with the polymerase accessory factor PCNA is operating. Here, we reconstituted a complete CAF-1 from fission yeast. We characterized its dynamic structure using NMR, SAXS and molecular modeling together with in vitro and in vivo functional studies on rationally designed interaction mutants. Importantly, we identify the unfolded nature of the acidic domain which folds up when binding to histones. We also show how the long KER helix mediates DNA binding and stimulates CAF-1 association with PCNA. Our study highlights how the organization of CAF-1 comprising both disordered regions and folded modules enables the dynamics of multiple interactions to promote synthesis-coupled histone deposition essential for its DNA replication, heterochromatin maintenance, and genome stability functions.
真核生物中的基因组和表观基因组完整性取决于组蛋白沉积与DNA合成的适当耦合。这一过程依赖于进化上保守的组蛋白伴侣CAF-1,其结构与功能之间的联系仍是一个谜。虽然对CAF-1复合物的研究能够提出一种组蛋白沉积机制的模型,但我们仍然缺乏一个框架来证明其普遍性,特别是其与聚合酶辅助因子PCNA的相互作用是如何发挥作用的。在这里,我们从裂殖酵母中重组了完整的CAF-1。我们使用核磁共振、小角X射线散射和分子建模以及对合理设计的相互作用突变体的体外和体内功能研究来表征其动态结构。重要的是,我们确定了酸性结构域的未折叠性质,该结构域在与组蛋白结合时会折叠起来。我们还展示了长KER螺旋如何介导DNA结合并刺激CAF-1与PCNA的结合。我们的研究突出了CAF-1的组织方式,即包含无序区域和折叠模块,如何实现多种相互作用的动态变化,以促进对其DNA复制、异染色质维持和基因组稳定性功能至关重要的合成偶联组蛋白沉积。