p66α-MBD2 coiled-coil interaction and recruitment of Mi-2 are critical for globin gene silencing by the MBD2-NuRD complex
p66α-MBD2 coiled-coil interaction and recruitment of Mi-2 are critical for globin gene silencing by the MBD2-NuRD complex
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DOI：
10.1073/pnas.1015341108
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发表时间：
2011-05-03
影响因子：
11.1
通讯作者：
Williams, David C., Jr.
中科院分区：
文献类型：
--
作者：
Gnanapragasam, Merlin Nithya;Scarsdale, J. Neel;Williams, David C., Jr.
核小体重塑复合物包括几个大家族的染色质修饰剂，整合多种表观遗传控制信号，在细胞类型特异性转录调控中发挥关键作用。我们先前从原代红系细胞中分离出一种含甲基结合结构域蛋白2（MBD 2）的核小体重塑和脱乙酰化（NuRD）复合物，并表明MBD 2有助于体内发育过程中DNA甲基化依赖的胚胎和胎儿β型珠蛋白基因沉默。在这里，我们提出了MBD 2和p66 α之间的卷曲螺旋相互作用的结构和生物物理细节，MBD 2-NuRD复合物的关键组成部分。我们发现，强制表达的孤立的p66 α卷曲螺旋结构域缓解MBD 2介导的珠蛋白基因沉默，表达的肽相互作用，只与一个子集的组件的MBD 2-NuRD复合物，不包括天然p66 a或Mi-2。这些结果证明了卷曲螺旋相互作用的核心重要性，并表明MBD 2依赖性DNA甲基化驱动的基因沉默可以通过选择性靶向这种卷曲螺旋复合物来破坏。
Nucleosome remodeling complexes comprise several large families of chromatin modifiers that integrate multiple epigenetic control signals to play key roles in cell type-specific transcription regulation. We previously isolated a methyl-binding domain protein 2 (MBD2)-containing nucleosome remodeling and deacetylation (NuRD) complex from primary erythroid cells and showed that MBD2 contributes to DNA methylation-dependent embryonic and fetal beta-type globin gene silencing during development in vivo. Here we present structural and biophysical details of the coiled-coil interaction between MBD2 and p66 alpha, a critical component of the MBD2-NuRD complex. We show that enforced expression of the isolated p66 alpha coiled-coil domain relieves MBD2-mediated globin gene silencing and that the expressed peptide interacts only with a subset of components of the MBD2-NuRD complex that does not include native p66a or Mi-2. These results demonstrate the central importance of the coiled-coil interaction and suggest that MBD2-dependent DNA methylation-driven gene silencing can be disrupted by selectively targeting this coiled-coil complex.