由HIR复合物和Asf1进行的不依赖复制的组蛋白沉积
Replication-independent histone deposition by the HIR complex and Asf1.
作者信息
Green Erin M, Antczak Andrew J, Bailey Aaron O, Franco Alexa A, Wu Kevin J, Yates John R, Kaufman Paul D
机构信息
Lawrence Berkeley National Laboratory and Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA.
出版信息
Curr Biol. 2005 Nov 22;15(22):2044-9. doi: 10.1016/j.cub.2005.10.053.
The orderly deposition of histones onto DNA is mediated by conserved assembly complexes, including chromatin assembly factor-1 (CAF-1) and the Hir proteins . CAF-1 and the Hir proteins operate in distinct but functionally overlapping histone deposition pathways in vivo . The Hir proteins and CAF-1 share a common partner, the highly conserved histone H3/H4 binding protein Asf1, which binds the middle subunit of CAF-1 as well as to Hir proteins . Asf1 binds to newly synthesized histones H3/H4 , and this complex stimulates histone deposition by CAF-1 . In yeast, Asf1 is required for the contribution of the Hir proteins to gene silencing . Here, we demonstrate that Hir1, Hir2, Hir3, and Hpc2 comprise the HIR complex, which copurifies with the histone deposition protein Asf1. Together, the HIR complex and Asf1 deposit histones onto DNA in a replication-independent manner. Histone deposition by the HIR complex and Asf1 is impaired by a mutation in Asf1 that inhibits HIR binding. These data indicate that the HIR complex and Asf1 proteins function together as a conserved eukaryotic pathway for histone replacement throughout the cell cycle.
组蛋白在DNA上的有序沉积由保守的组装复合物介导，包括染色质组装因子1（CAF-1）和Hir蛋白。在体内，CAF-1和Hir蛋白在不同但功能重叠的组蛋白沉积途径中发挥作用。Hir蛋白和CAF-1共享一个共同的伙伴，即高度保守的组蛋白H3/H4结合蛋白Asf1，它与CAF-1的中间亚基以及Hir蛋白结合。Asf1与新合成的组蛋白H3/H4结合，并且这种复合物刺激CAF-1介导的组蛋白沉积。在酵母中，Asf1是Hir蛋白对基因沉默起作用所必需的。在此，我们证明Hir1、Hir2、Hir3和Hpc2组成了HIR复合物，该复合物与组蛋白沉积蛋白Asf1共同纯化。HIR复合物和Asf1一起以不依赖复制的方式将组蛋白沉积到DNA上。HIR复合物和Asf1介导的组蛋白沉积会因Asf1中抑制HIR结合的突变而受损。这些数据表明，HIR复合物和Asf1蛋白共同作为一种保守的真核途径，在整个细胞周期中进行组蛋白置换。
Zotero 插件