Ding Niannian, Chen Yuanyuan, Chu Yindi, Zhong Cheng, Huang Li, Zhang Zhenfeng
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing, China.
College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.
Front Microbiol. 2022 Mar 3;13:837737. doi: 10.3389/fmicb.2022.837737. eCollection 2022.
Cren7 and Sis7d, two chromatin proteins from , undergo extensive methylations at multiple lysine residues to various extents. Whether this highly conserved protein serves an epigenetic role in the regulation of the structure and function of the chromosome remains unclear. In the present study, we show that methylation significantly affects Cren7, but not Sis7d, in the ability to bind DNA and to constrain negative DNA supercoils. Strikingly, methylated Cren7 was significantly less efficient in forming oligomers or mediating intermolecular DNA bridging. Single-site substitution mutation with glutamine reveals that methylation of the four lysine residues (K24, K31, K42, and K48) of Cren7 at the protein-DNA interface, which are variably conserved among Cren7 homologues from different branches of the Crenarchaeota, influenced Cren7-DNA interactions in different manners. We suggest that dynamic methylation of Cren7 may represent a potential epigenetic mechanism involved in the chromosomal regulation in crenarchaea.
来自[具体来源未给出]的两种染色质蛋白Cren7和Sis7d在多个赖氨酸残基上经历了不同程度的广泛甲基化。这种高度保守的蛋白质是否在染色体结构和功能的调控中发挥表观遗传作用仍不清楚。在本研究中，我们发现甲基化显著影响Cren7结合DNA和约束负超螺旋DNA的能力，但对Sis7d没有影响。令人惊讶的是，甲基化的Cren7在形成寡聚体或介导分子间DNA桥接方面的效率显著降低。用谷氨酰胺进行的单点取代突变表明，Cren7在蛋白质-DNA界面的四个赖氨酸残基（K24、K31、K42和K48）的甲基化，在来自泉古菌不同分支的Cren7同源物中具有不同程度的保守性，以不同方式影响Cren7与DNA的相互作用。我们认为，Cren7的动态甲基化可能代表了一种参与泉古菌染色体调控的潜在表观遗传机制。
