State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.
Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
Elife. 2017 Oct 13;6:e30178. doi: 10.7554/eLife.30178.
Histone tail modifications can greatly influence chromatin-associated processes. Asymmetrically modified nucleosomes exist in multiple cell types, but whether modifications on both sister histones contribute equally to chromatin dynamics remains elusive. Here, we devised a bivalent nucleosome system that allowed for the constitutive assembly of asymmetrically modified sister histone H3s in nucleosomes in . The sister H3K36 methylations independently affected cryptic transcription in gene coding regions, whereas sister H3K79 methylation had cooperative effects on gene silencing near telomeres. H3K4 methylation on sister histones played an independent role in suppressing the recruitment of Gal4 activator to the promoter and in inhibiting transcription. Under starvation stress, sister H3K4 methylations acted cooperatively, independently or redundantly to regulate transcription. Thus, we provide a unique tool for comparing symmetrical and asymmetrical modifications of sister histone H3s in vivo.
组蛋白尾部修饰可以极大地影响与染色质相关的过程。在多种细胞类型中都存在不对称修饰的核小体，但两个姐妹染色质上的修饰是否平等地影响染色质动力学仍然难以捉摸。在这里，我们设计了一种双价核小体系统，允许在核小体中组成性地组装不对称修饰的姐妹组蛋白 H3。姐妹 H3K36 甲基化独立地影响基因编码区的隐蔽转录，而姐妹 H3K79 甲基化对端粒附近基因沉默有协同作用。姐妹染色质上的 H3K4 甲基化在抑制 Gal4 激活因子与启动子的招募和抑制转录中发挥独立作用。在饥饿应激下，姐妹 H3K4 甲基化以协同、独立或冗余的方式调节转录。因此，我们提供了一个独特的工具，用于比较体内姐妹组蛋白 H3 的对称和不对称修饰。
