PT - JOURNAL ARTICLE AU - Xuefang Xu AU - Heng Zhang AU - Ying Huang AU - Yuan Zhang AU - Xiaoyuan Wang AU - Dai Wang AU - Ji Pu AU - Hongqing Zhao AU - Xuancheng Lu AU - Shuangshuang Lu AU - Yanwen Xiong AU - Changyun Ye AU - Yuhui Dong AU - Ruiting Lan AU - Jianguo Xu TI - Beyond a ribosomal RNA methyltransferase, the wider role of MraW in DNA methylation, motility and colonization in <em>Escherichia coli</em> O157:H7 AID - 10.1101/480244 DP - 2018 Jan 01 TA - bioRxiv PG - 480244 4099 - http://biorxiv.org/content/early/2018/11/29/480244.short 4100 - http://biorxiv.org/content/early/2018/11/29/480244.full AB - MraW (RsmH) is an AdoMet-dependent 16S rRNA methyltransferase conserved in bacteria and plays a role in the fine-tuning of the ribosomal decoding center. It was recently found to contribute to the virulence of Staphylococcus aureus in host animals. In this study, we examined the function of MraW in Escherichia coli O157:H7 and found that deletion of mraW led to decreased motility and flagellar production. Whole-genome bisulfite sequencing showed genome wide decrease of methylation of 336 genes and 219 promoters in the mraW mutant. The methylation level of 4 flagellar gene sequences were further confirmed by bisulfite PCR sequencing. Quantitative reverse transcription PCR results indicated the transcription of these genes was also affected. MraW was observed to directly bind to the four flagellar gene sequences by electrophoretic mobility shift assay (EMSA). A common motif in differentially methylated regions of promoters and coding regions of the 4 flagellar genes was identified. Reduced methylation was correlated with altered expression of 21 of the 24 genes tested. DNA methylation activity of MraW was confirmed by DNA methyltransferase (DNMT) activity assay in vitro. The mraW mutant colonized poorer than wild type in mice. we further found that the expression of mraZ in the mraW mutant was increased confirming the antagonistic effect of mraW on mraZ. In conclusion, mraW was found to be a DNA methylase and has a wide-ranging effect on E. coli O157:H7 including motility and virulence in vivo via genome wide methylation and mraZ antagonism.IMPORTANCE MraW is a well-studied 16S rRNA methyltransferase and was recently found have an impact on bacterial virulence. Here we demonstrated its new function as a DNA methylase and effect on motility, colonization in mice, DNA methylation in genome wide and contribution to virulence. Its direct binding of differentially methylated flagellar-encoding DNA sequences was observed, indicating a correlation between DNA methylation and regulation of flagellar genes. In addition, the expression of mraZ which function as an antagonist of mraW was increased in the mraW mutant. mraW plays an important role in gene regulation likely through DNA methylation. Clearly it plays a role in virulence in E. coli O157:H7. It also opens a new research field for virulence study in bacteria.