Li Qing, Burgess Rebecca, Zhang Zhiguo
Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.
Biochim Biophys Acta. 2013 Mar-Apr;1819(3-4):238-46.
Chromatin, a complex of DNA and associated proteins, governs diverse processes including gene transcription, DNA replication and DNA repair. The fundamental unit of chromatin is the nucleosome, consisting of 147 bp of DNA wound about 1.6 turns around a histone octamer of one (H3-H4)2 tetramer and two H2A-H2B dimers. In order to form nucleosomes, (H3-H4)2 tetramers are deposited first, followed by the rapid deposition of H2A-H2B. It is believed that the assembly of (H3-H4)2 tetramers into nucleosomes is the rate-limiting step of nucleosome assembly. Moreover, assembly of H3-H4 into nucleosomes following DNA replication, DNA repair and gene transcription is likely to be a key step in the inheritance of epigenetic information and maintenance of genome integrity. In this review, we discuss how nucleosome assembly of H3-H4 is regulated by concerted actions of histone chaperones and modifications on newly synthesized H3 and H4. This article is part of a Special Issue entitled: Histone chaperones and Chromatin assembly.
染色质是一种由DNA和相关蛋白质组成的复合物，它调控着包括基因转录、DNA复制和DNA修复在内的多种过程。染色质的基本单位是核小体，它由147个碱基对的DNA缠绕在一个由一个（H3-H4）2四聚体和两个H2A-H2B二聚体组成的组蛋白八聚体上，缠绕约1.6圈。为了形成核小体，（H3-H4）2四聚体首先沉积，随后H2A-H2B快速沉积。据信，（H3-H4）2四聚体组装成核小体是核小体组装的限速步骤。此外，在DNA复制、DNA修复和基因转录后，H3-H4组装成核小体可能是表观遗传信息遗传和基因组完整性维持的关键步骤。在这篇综述中，我们讨论了H3-H4的核小体组装是如何受到组蛋白伴侣的协同作用以及新合成的H3和H4上的修饰的调控的。本文是名为“组蛋白伴侣与染色质组装”的特刊的一部分。
