Interdisciplinary Research Institute, CNRS-Université Lille Nord de France, 50 Avenue Halley, Villeneuve d'Ascq, France.
Interdisciplinary Research Institute, CNRS-Université Lille Nord de France, 50 Avenue Halley, Villeneuve d'Ascq, France.
Trends Microbiol. 2014 Sep;22(9):528-35. doi: 10.1016/j.tim.2014.05.003. Epub 2014 Jun 2.
In Caulobacter crescentus, methylation of DNA by CcrM plays an important part in the regulation of cell cycle progression. Thanks to this methyltransferase, the activity of which is cell cycle regulated, the chromosome transitions between a hemimethylated state in the S-phase to a fully methylated condition in the G1 and G2 phases. Any perturbation in CcrM expression, such as depletion or constitutive expression, causes severe developmental defects. Several studies suggest that the role of CcrM is conserved across the Alphaproteobacteria. In the past few years, the importance of methylation on the expression of cell cycle regulated genes has emerged, suggesting that CcrM-dependent methylation can direct the binding of transcription factors to specific methylated sequences and affect the expression of genes depending on the methylation state of their promoters. CcrM activity has recently been linked to GcrA, a cell cycle master regulator that controls the expression of several genes during S-phase. Here, we review recent findings that establish the global role of methylation in cell cycle progression, and also explore the significance of a CcrM-GcrA epigenetic module that has co-evolved in Alphaproteobacteria, including Caulobacter, in controlling several genes involved in cell division, polarity, and motility.
在新月柄杆菌（Caulobacter crescentus）中，由 CcrM 对 DNA 的甲基化在细胞周期进程的调控中起着重要作用。多亏了这种甲基转移酶，其活性受到细胞周期的调节，染色体在 S 期从半甲基化状态转变为 G1 和 G2 期的完全甲基化状态。CcrM 表达的任何干扰，如耗竭或组成型表达，都会导致严重的发育缺陷。几项研究表明，CcrM 的作用在 α-变形菌中是保守的。在过去的几年里，甲基化对细胞周期调控基因表达的重要性已经显现出来，这表明 CcrM 依赖性甲基化可以指导转录因子与特定的甲基化序列结合，并根据启动子的甲基化状态影响基因的表达。CcrM 的活性最近与 GcrA 有关，GcrA 是一个细胞周期主调控因子，它在 S 期控制着几个基因的表达。在这里，我们回顾了最近的发现，这些发现确立了甲基化在细胞周期进程中的全局作用，并探讨了 CcrM-GcrA 表观遗传模块在控制与细胞分裂、极性和运动相关的几个基因方面的重要性，该模块在包括新月柄杆菌在内的 α-变形菌中共同进化。
