Sato Shoko, Dacher Mariko, Kurumizaka Hitoshi
Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
Epigenomes. 2022 Aug 2;6(3):22. doi: 10.3390/epigenomes6030022.
In eukaryotes, genomic DNA is bound with histone proteins and packaged into chromatin. The nucleosome, a fundamental unit of chromatin, regulates the accessibility of DNA to enzymes involved in gene regulation. During the past few years, structural analyses of chromatin architectures have been limited to evolutionarily related organisms. The amino acid sequences of histone proteins are highly conserved from humans to yeasts, but are divergent in the deeply branching protozoan groups, including human parasites that are directly related to human health. Certain large DNA viruses, as well as archaeal organisms, contain distant homologs of eukaryotic histone proteins. The divergent sequences give rise to unique and distinct nucleosome architectures, although the fundamental principles of histone folding and DNA contact are highly conserved. In this article, we review the structures and biophysical properties of nucleosomes containing histones from the human parasites and , and histone-like proteins from the amoeba virus family. The presented data confirm the sharing of the overall DNA compaction system among evolutionally distant species and clarify the deviations from the species-specific nature of the nucleosome.
在真核生物中，基因组DNA与组蛋白结合并包装成染色质。核小体作为染色质的基本单位，调控着DNA对于参与基因调控的酶的可及性。在过去几年中，染色质结构的结构分析仅限于进化相关的生物体。从人类到酵母，组蛋白的氨基酸序列高度保守，但在包括与人类健康直接相关的人类寄生虫在内的深度分支原生动物类群中则有所不同。某些大型DNA病毒以及古生菌含有真核组蛋白的远缘同源物。尽管组蛋白折叠和DNA接触的基本原理高度保守，但这些不同的序列产生了独特且各异的核小体结构。在本文中，我们综述了来自人类寄生虫和的组蛋白以及变形虫病毒家族的组蛋白样蛋白的核小体的结构和生物物理特性。所呈现的数据证实了在进化距离遥远的物种之间存在整体DNA压缩系统的共享，并阐明了与核小体物种特异性本质的偏差。
