Nanotechnology Research Centre, National Research Council of Canada, 11421 Saskatchewan Drive, Edmonton, AB, T6G 2M9, Canada.
Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe657-8501, Japan.
Microsc Microanal. 2021 Feb;27(1):149-155. doi: 10.1017/S1431927620024666.
It is well known that two DNA molecules are wrapped around histone octamers and folded together to form a single chromosome. However, the nucleosome fiber folding within a chromosome remains an enigma, and the higher-order structure of chromosomes also is not understood. In this study, we employed electron diffraction which provides a noninvasive analysis to characterize the internal structure of chromosomes. The results revealed the presence of structures with 100–200 nm periodic features directionally perpendicular to the chromosome axis in unlabeled isolated human chromosomes. We also visualized the 100–200 nm periodic features perpendicular to the chromosome axis in an isolated chromosome whose DNA molecules were specifically labeled with OsO4 using electron tomography in 300 keV and 1 MeV transmission electron microscopes.
众所周知，两条 DNA 分子缠绕在组蛋白八聚体周围并折叠在一起形成单个染色体。然而，染色体内部的核小体纤维折叠仍然是一个谜，染色体的高级结构也尚不清楚。在这项研究中，我们采用电子衍射，这种非侵入性的分析方法来表征染色体的内部结构。结果表明，在未标记的分离人染色体中存在具有 100-200nm 周期性特征的结构，这些特征的方向垂直于染色体轴。我们还使用 300keV 和 1MeV 透射电子显微镜的电子断层扫描技术，观察到经 OsO4 特异性标记 DNA 分子的分离染色体中，垂直于染色体轴的 100-200nm 周期性特征。
