UFIP UMR-CNRS 6286, Epigénétique: prolifération et différenciation, Faculté des Sciences et des Techniques, 2 rue de la Houssinière, 44322, Nantes, France.
Sci Rep. 2017 Jun 8;7(1):3050. doi: 10.1038/s41598-017-03218-6.
Concomitant chromatin assembly and DNA duplication is essential for cell survival and genome integrity, and requires newly synthesized histones. Although the N-terminal domains of newly synthesized H3 and H4 present critical functions, their requirement for replication-coupled chromatin assembly is controversial. Using the unique capability of the spontaneous internalization of exogenous proteins in Physarum, we showed that H3 and H4 N-tails present critical functions in nuclear import during the S-phase, but are dispensable for assembly into nucleosomes. However, our data revealed that chromatin assembly in the S-phase of complexes presenting ectopic N-terminal domains occurs by a replication-independent mechanism. We found that replication-dependent chromatin assembly requires an H3/H4 complex with the relevant N-tail domains, suggesting a concomitant recognition of the two histone domains by histone chaperones.
伴随染色质组装和 DNA 复制对于细胞存活和基因组完整性至关重要，需要新合成的组蛋白。虽然新合成的 H3 和 H4 的 N 端结构域具有关键功能，但它们对复制偶联染色质组装的需求存在争议。利用 Physarum 中外源蛋白自发内化的独特能力，我们表明 H3 和 H4 N 端在 S 期的核内输入过程中具有关键功能，但对于组装成核小体则不是必需的。然而，我们的数据显示，在具有异位 N 端结构域的复合物中，S 期的染色质组装是通过一种与复制无关的机制发生的。我们发现，依赖复制的染色质组装需要具有相关 N 端结构域的 H3/H4 复合物，这表明组蛋白伴侣同时识别这两个组蛋白结构域。
