甲基化修饰在细菌表观调控中的功能

Epigenetic regulation role of DNA methylation in bacteria

为了适应复杂多变的生存环境,微生物通常需要在保证基因组序列不变的前提下不断调整胞内代谢网络。表观调控可以在不改变DNA序列的情况下对基因表达进行调控,因此成为细菌中重要的调控方式。作为一种DNA修饰,DNA甲基化修饰是生物体中最常见的表观调控工具。在本文中我们全面、深入解析了两种孤儿甲基转移酶:DNA腺嘌呤甲基转移酶(DNA adenine methyltransferase,Dam)和细胞周期调控甲基转移酶(Cell cycle-regulated methyltransferase,Ccr M)在原核生物中的表观调控功能。我们主要探讨了DNA甲基化参与的细胞生理过程包括DNA复制起始、DNA错配修复、基因表达调控、致病性和相变异等方面。同时,我们结合三维基因组研究技术基因组结构捕获(Chromosome conformation capture,3C)技术和新型DNA磷硫酰化修饰讨论了该领域的发展前景。

To accommodate the variable environments, bacterial cells often need to take swift changes on metabolism while keep their genomic sequence unchanged. Thus, epigenetic regulation becomes an important way for bacteria because no genomic alteration is required. As one of the DNA modifications, DNA methylation is the most well-known epigenetic tools among all the organisms. Here in this review, we gave a comprehensive introduction of two orphan methyltransferases Dam（DNA adenine methyltransferase） and Ccr M（Cell cycle-regulated methyltransferase）, as examples of epigenetic regulation in prokaryotes. We majorly talked about their role in bacterial DNA replication initiation, DNA mismatch repair, regulation of gene expression, virulence and phase variation. Moreover, we also discussed the trends in this field based on a newly-generated technology Chromosome Conformation Capture（3 C） and a novel DNA phosphorothioate modification.