Dynamic Organization of Chromatin Domains Revealed by Super-Resolution Live-Cell Imaging
Dynamic Organization of Chromatin Domains Revealed by Super-Resolution Live-Cell Imaging
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DOI：
10.1016/j.molcel.2017.06.018
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发表时间：
2017-07-20
期刊：
影响因子：
16
通讯作者：
Maeshima, Kazuhiro
中科院分区：
文献类型：
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作者：
Nozaki, Tadasu;Imai, Ryosuke;Maeshima, Kazuhiro
真核生物的基因组在细胞内组织为染色质。为了正确的信息输出，可以动态地调节高阶染色质结构。这些结构如何在各种细胞过程中形成和表现尚不清楚。在这里，通过结合超分辨率成像（光激活定位显微镜[PALM]）和单核小体跟踪，我们开发了一个核成像系统，可视化的高阶结构沿着与它们的动态在活的哺乳动物细胞。我们证明，核小体形成紧凑的域与类似的峰值直径为160 nm，并在活细胞中相干移动。富含异染色质的区域显示更多的结构域和较少的运动。随着细胞分化，结构域变得更加明显，动力学降低。此外，各种扰动实验表明，它们是由一系列因素组成的，包括粘着蛋白和核小体-核小体相互作用。值得注意的是，我们在有丝分裂过程中观察到的结构域，这表明它们作为染色体的构建块，并可能作为整个细胞周期的信息单元。
The eukaryotic genome is organized within cells as chromatin. For proper information output, higher-order chromatin structures can be regulated dynamically. How such structures form and behave in various cellular processes remains unclear. Here, by combining super-resolution imaging (photoactivated localization microscopy [PALM]) and single-nucleosome tracking, we developed a nuclear imaging system to visualize the higher-order structures along with their dynamics in live mammalian cells. We demonstrated that nucleosomes form compact domains with a peak diameter of similar to 160 nm and move coherently in live cells. The heterochromatin-rich regions showed more domains and less movement. With cell differentiation, the domains became more apparent, with reduced dynamics. Furthermore, various perturbation experiments indicated that they are organized by a combination of factors, including cohesin and nucleosome-nucleosome interactions. Notably, we observed the domains during mitosis, suggesting that they act as building blocks of chromosomes and may serve as information units throughout the cell cycle.