Guschin D, Wade P A, Kikyo N, Wolffe A P
Laboratory of Molecular Embryology, National Institute of Child Health and Human Development, National Institutes of Health, Building 18T, Room 106, Bethesda, Maryland 20892-5431, USA.
Biochemistry. 2000 May 9;39(18):5238-45. doi: 10.1021/bi000421t.
The Mi-2 complex has been implicated in chromatin remodeling and transcriptional repression associated with histone deacetylation. Here, we use a purified Mi-2 complex containing six components, Mi-2, Mta 1-like, p66, RbAp48, RPD3, and MBD3, to investigate the capacity of this complex to destabilize histone-DNA interactions and deacetylate core histones. The Mi-2 complex has ATPase activity that is stimulated by nucleosomes but not by free histones or DNA. This nucleosomal ATPase is relatively inefficient, yet is essential to facilitate both translational movement of histone octamers relative to DNA and the efficient deacetylation of the core histones within a mononucleosome. Surprisingly, ATPase activity had no effect on deacetylation of nucleosomal arrays.
Mi-2复合物与染色质重塑以及与组蛋白去乙酰化相关的转录抑制有关。在此，我们使用一种纯化的包含六个组分（Mi-2、Mta 1样蛋白、p66、RbAp48、RPD3和MBD3）的Mi-2复合物，来研究该复合物破坏组蛋白-DNA相互作用以及使核心组蛋白去乙酰化的能力。Mi-2复合物具有ATP酶活性，该活性受到核小体的刺激，但不受游离组蛋白或DNA的刺激。这种核小体ATP酶效率相对较低，但对于促进组蛋白八聚体相对于DNA的平移运动以及单核小体内核心组蛋白的有效去乙酰化至关重要。令人惊讶的是，ATP酶活性对核小体阵列的去乙酰化没有影响。
