Partitioning of Histone H3-H4 Tetramers During DNA Replication-Dependent Chromatin Assembly
Partitioning of Histone H3-H4 Tetramers During DNA Replication-Dependent Chromatin Assembly
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DOI：
10.1126/science.1178994
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发表时间：
2010-04-02
期刊：
影响因子：
56.9
通讯作者：
Zhu, Bing
中科院分区：
文献类型：
--
作者：
Xu, Mo;Long, Chengzu;Zhu, Bing
半保守的 DNA 复制确保了细胞分裂过程中遗传信息的忠实复制。然而，组蛋白修饰携带的表观遗传信息如何通过有丝分裂传播仍然难以捉摸。为了解决这个问题，必须阐明 DNA 复制依赖性核小体分配模式。在这里，我们报告了大量的 H3.3-H4 四聚体在体内分裂，而大多数 H3.1-H4 四聚体保持完整。抑制 DNA 复制依赖性沉积大大降低了分裂事件的水平，这表明 (i) 不依赖于复制的 H3.3 沉积途径主要是通过协同整合两个新的 H3.3-H4 二聚体进行的，并且 (ii) 大多数分裂事件发生在复制依赖性沉积期间。我们的结果支持这样的观点，即大异染色质区域内的“沉默”组蛋白修饰是通过复制邻近预先存在的组蛋白的修饰来维持的，而不需要 H3-H4 分裂事件。
Semiconservative DNA replication ensures the faithful duplication of genetic information during cell divisions. However, how epigenetic information carried by histone modifications propagates through mitotic divisions remains elusive. To address this question, the DNA replication-dependent nucleosome partition pattern must be clarified. Here, we report significant amounts of H3.3-H4 tetramers split in vivo, whereas most H3.1-H4 tetramers remained intact. Inhibiting DNA replication-dependent deposition greatly reduced the level of splitting events, which suggests that (i) the replication-independent H3.3 deposition pathway proceeds largely by cooperatively incorporating two new H3.3-H4 dimers and (ii) the majority of splitting events occurred during replication-dependent deposition. Our results support the idea that "silent" histone modifications within large heterochromatic regions are maintained by copying modifications from neighboring preexisting histones without the need for H3-H4 splitting events.