Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
Biochim Biophys Acta Gene Regul Mech. 2022 Oct;1865(7):194851. doi: 10.1016/j.bbagrm.2022.194851. Epub 2022 Aug 8.
Chromatin is a dynamic molecular complex composed of DNA and proteins that package the DNA in the nucleus of eukaryotic cells. The basic structural unit of chromatin is the nucleosome core particle, composed of ~150 base pairs of genomic DNA wrapped around a histone octamer containing two copies each of four histones, H2A, H2B, H3, and H4. Individual nucleosome core particles are connected by short linker DNAs, forming a nucleosome array known as a beads-on-a-string fiber. Higher-order structures of chromatin are closely linked to nuclear events such as replication, transcription, recombination, and repair. Recently, a variety of chromatin structures have been determined by single-particle cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET), and their structural details have provided clues about the chromatin architecture functions in the cell. In this review, we highlight recent cryo-EM structural studies of a fundamental chromatin unit to clarify the functions of chromatin.
染色质是一种动态的分子复合物，由 DNA 和蛋白质组成，它将真核细胞细胞核中的 DNA 进行包装。染色质的基本结构单位是核小体核心颗粒，由约 150 个碱基对的基因组 DNA 缠绕在包含两个拷贝的每个组蛋白 H2A、H2B、H3 和 H4 的组蛋白八聚体周围。单个核小体核心颗粒通过短的连接 DNA 连接，形成称为珠串纤维的核小体阵列。染色质的高级结构与核复制、转录、重组和修复等事件密切相关。最近，通过单颗粒冷冻电子显微镜（cryo-EM）和冷冻电子断层扫描（cryo-ET）确定了多种染色质结构，其结构细节为染色质在细胞中的结构功能提供了线索。在这篇综述中，我们强调了最近关于基本染色质单元的 cryo-EM 结构研究，以阐明染色质的功能。
