Methyltransferase DnmA is responsible for genome-wide N6-methyladenosine modifications at non-palindromic recognition sites in Bacillus subtilis
Methyltransferase DnmA is responsible for genome-wide N6-methyladenosine modifications at non-palindromic recognition sites in Bacillus subtilis
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DOI：
10.1093/nar/gkaa266
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发表时间：
2020-06-04
影响因子：
14.9
通讯作者：
Simmons, Lyle A.
中科院分区：
文献类型：
--
作者：
Nye, Taylor M.;van Gijtenbeek, Lieke A.;Simmons, Lyle A.
来自所有三个生命领域的生物体的基因组以DNA甲基化的形式存在内源性碱基修饰。在细菌基因组中，甲基化发生在腺苷和胞苷残基上，包括N6-甲基腺嘌呤（m6 A）、5-甲基胞嘧啶（m5 C）和N4-甲基胞嘧啶（m4 C）。细菌DNA甲基化在限制修饰（RM）系统中得到了很好的表征，其中甲基化通过同源限制性内切酶调节DNA切割。相对于RM系统，关于m6 A如何有助于革兰氏阳性菌中细胞功能的表观遗传调控知之甚少。在这里，我们的特征位点特异性的m6 A修饰的非回文序列GACGmAG内的枯草芽孢杆菌菌株的基因组。我们证明，yeeA基因是一个甲基转移酶负责的m6 A修饰的存在。我们表明，从YeeA甲基化不起作用，以限制在自然转化过程中的DNA摄取。相反，我们确定了一个子集的启动子，包含甲基化的共识序列，并表明启动子区域内的甲基化的损失导致报告基因表达的减少。此外，我们确定了一个转录抑制因子，优先结合报告基因测定中使用的未甲基化的启动子。根据这些结果，我们认为B.枯草芽孢杆菌的功能，以促进基因表达。
The genomes of organisms from all three domains of life harbor endogenous base modifications in the form of DNA methylation. In bacterial genomes, methylation occurs on adenosine and cytidine residues to include N6-methyladenine (m6A), 5-methylcytosine (m5C), and N4-methylcytosine (m4C). Bacterial DNA methylation has been well characterized in the context of restriction-modification (RM) systems, where methylation regulates DNA incision by the cognate restriction endonuclease. Relative to RM systems less is known about how m6A contributes to the epigenetic regulation of cellular functions in Gram-positive bacteria. Here, we characterize site-specific m6A modifications in the non-palindromic sequence GACGmAG within the genomes of Bacillus subtilis strains. We demonstrate that the yeeA gene is a methyltransferase responsible for the presence of m6A modifications. We show that methylation from YeeA does not function to limit DNA uptake during natural transformation. Instead, we identify a subset of promoters that contain the methylation consensus sequence and show that loss of methylation within promoter regions causes a decrease in reporter expression. Further, we identify a transcriptional repressor that preferentially binds an unmethylated promoter used in the reporter assays. With these results we suggest that m6A modifications in B. subtilis function to promote gene expression.