Centromeres are maintained by fastening CENP-A to DNA and directing an arginine anchor-dependent nucleosome transition.
Centromeres are maintained by fastening CENP-A to DNA and directing an arginine anchor-dependent nucleosome transition.
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DOI：
10.1038/ncomms15775
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发表时间：
2017-06-09
影响因子：
16.6
通讯作者：
Black BE
中科院分区：
文献类型：
--
作者：
Guo LY;Allu PK;Zandarashvili L;McKinley KL;Sekulic N;Dawicki-McKenna JM;Fachinetti D;Logsdon GA;Jamiolkowski RM;Cleveland DW;Cheeseman IM;Black BE
维持着丝粒的同一性依赖于由组蛋白H3变体，着丝粒蛋白A（CENP-A）提供的表观遗传标记的持久性，但其显着稳定性的分子机制仍不清楚。在这里，我们定义了三个候选CENP-A核小体结合结构域（两个在CENP-C上，一个在CENP-N上）中的每一个对CENP-A稳定性的贡献，使用基因替换和快速蛋白质降解。令人惊讶的是，最保守的结构域，CENP-C基序，是p2p。相反，稳定性是由CENP-C的未折叠的中心结构域和CENP-N的折叠的N-末端结构域赋予的，所述N-末端结构域在交联CENP-A及其相邻的核小体DNA时变得刚性化1,000倍。破坏CENP-C上用于核小体酸性补丁的“精氨酸锚”会破坏CENP-A核小体结构转换并从着丝粒中去除CENP-A核小体。CENP-A核小体在着丝粒处的保留需要核心着丝粒核小体复合物，其中CENP-C钳制稳定的核小体构象，CENP-N将CENP-A固定到DNA上。着丝粒的维持依赖于组蛋白变体CENP-A在着丝粒处的持续存在。在这里，作者表征了核心着丝粒核小体复合物，其中CENP-C赋予稳定的CENP-A核小体构象，CENP-N将CENP-A赋予DNA。
Maintaining centromere identity relies upon the persistence of the epigenetic mark provided by the histone H3 variant, centromere protein A (CENP-A), but the molecular mechanisms that underlie its remarkable stability remain unclear. Here, we define the contributions of each of the three candidate CENP-A nucleosome-binding domains (two on CENP-C and one on CENP-N) to CENP-A stability using gene replacement and rapid protein degradation. Surprisingly, the most conserved domain, the CENP-C motif, is dispensable. Instead, the stability is conferred by the unfolded central domain of CENP-C and the folded N-terminal domain of CENP-N that becomes rigidified 1,000-fold upon crossbridging CENP-A and its adjacent nucleosomal DNA. Disrupting the ‘arginine anchor' on CENP-C for the nucleosomal acidic patch disrupts the CENP-A nucleosome structural transition and removes CENP-A nucleosomes from centromeres. CENP-A nucleosome retention at centromeres requires a core centromeric nucleosome complex where CENP-C clamps down a stable nucleosome conformation and CENP-N fastens CENP-A to the DNA. Centromere maintenance depends on the persistence of the histone variant CENP-A at the centromeres. Here, the authors characterize the core centromeric nucleosome complex wherein CENP-C confers a stable CENP-A nucleosome conformation and CENP-N fastens CENP-A to the DNA.