Institute of Translational Research, Tongji Hospital, the School of Life Sciences and Technology, Shanghai Key Laboratory of Signaling and Disease Research, the Collaborative Innovation Center for Brain Science, Tongji University, Shanghai, 200092, China.
Department of laboratory medicine, the first people's Hospital of Ninghai County, Ningbo city, 315600, China.
Cell Death Dis. 2018 Jul 9;9(7):765. doi: 10.1038/s41419-018-0819-z.
The linker histone H1 is critical to maintenance of higher-order chromatin structures and to gene expression regulation. However, H1 dynamics and its functions in embryonic development remain unresolved. Here, we profiled gene expression, nucleosome positions, and H1 locations in early Drosophila embryos. The results show that H1 binding is positively correlated with the stability of beads-on-a-string nucleosome organization likely through stabilizing nucleosome positioning and maintaining nucleosome spacing. Strikingly, nucleosomes with H1 placement deviating to the left or the right relative to the dyad shift to the left or the right, respectively, during early Drosophila embryonic development. H1 occupancy on genic nucleosomes is inversely correlated with nucleosome distance to the transcription start sites. This inverse correlation reduces as gene transcription levels decrease. Additionally, H1 occupancy is lower at the 5' border of genic nucleosomes than that at the 3' border. This asymmetrical pattern of H1 occupancy on genic nucleosomes diminishes as gene transcription levels decrease. These findings shed new lights into how H1 placement dynamics correlates with nucleosome positioning and gene transcription during early Drosophila embryonic development.
连接组蛋白 H1 对于维持高级染色质结构和基因表达调控至关重要。然而，H1 的动态及其在胚胎发育中的功能仍未得到解决。在这里，我们对早期果蝇胚胎中的基因表达、核小体位置和 H1 位置进行了分析。结果表明，H1 结合与串珠核小体组织的稳定性呈正相关，可能通过稳定核小体定位和维持核小体间距来实现。引人注目的是，在早期果蝇胚胎发育过程中，相对于二分体向左或向右偏离的带有 H1 放置的核小体分别向左或向右移动。带有 H1 的基因核小体上的占有率与核小体到转录起始位点的距离呈负相关。这种负相关随着基因转录水平的降低而降低。此外，H1 在基因核小体 5'边界的占有率低于 3'边界。这种基因核小体上 H1 占有率的不对称模式随着基因转录水平的降低而减弱。这些发现为 H1 位置动力学如何与早期果蝇胚胎发育过程中的核小体定位和基因转录相关联提供了新的线索。
