Comparative methylome analysis of Campylobacter jejuni strain YH002 reveals a putative novel motif and diverse epigenetic regulations of virulence genes

Authors: GHATAK, SANDEEP - Indian Institute Of Technology; Armstrong, Cheryl; Reed, Sue; He, Yiping

Submitted to: Frontiers in Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/23/2020
Publication Date: 12/23/2020
Citation: Ghatak, S., Armstrong, C.M., Reed, S.A., He, Y. 2020. Comparative methylome analysis of Campylobacter jejuni strain YH002 reveals a putative novel motif and diverse epigenetic regulations of virulence genes. Frontiers in Microbiology. https://doi.org/10.3389/fmicb.2020.610395.
DOI: https://doi.org/10.3389/fmicb.2020.610395

Interpretive Summary: Methylation of the genome is highly important in prokaryotic biology because of its role in defending against intruding nucleic acids through restriction-modification (RM) systems and regulating gene expression patterns. Therefore, a methylation analysis was performed on C. jejuni YH002, a strain isolated from beef liver. The output was compared with two other well-studied C. jejuni strains, exposing a putative novel motif for a RM system. Additional investigations revealed several virulence genes within the genome that are putatively regulated by DNA methylation. Genes involved with motility, regulation of surface proteins, toxin production, and antibiotic resistance were the most noteworthy.

Technical Abstract: Campylobacter jejuni is a major cause of foodborne gastroenteritis worldwide inflicting palpable socioeconomic costs. The ability of this pathogen to successfully infect its hosts is determined not only by the presence of specific virulence genes but also by the pathogen’s capacity to appropriately regulate those virulence gene. Therefore, DNA methylation can play a critical role in both aspects of this process because it serves as both a means to protect the integrity of the cellular DNA from invasion and as a mechanism to control transcriptional regulation within the cell. In the present study we report the comparative methylome data of C. jejuni YH002, a multidrug resistant strain isolated from retail beef liver. Investigation into the methylome identified a putative novel motif (CGCGA) of a type II restriction-modification (RM) system. Comparison of methylomes of the strain to well-studied C. jejuni strains highlighted non-uniform methylation patterns among the strains though the existence of the typical type I and type IV RM systems were also observed. Additional investigations regarding transcriptional regulation associated with DNA methylation revealed several virulence genes within the genome putatively regulated using this mode of action, with those genes related to flagellum production (flhF, fliD, fliG, fliH, fliL, and filW), the RNA polymerase sigma factor (rpoN), the B subunit of cytolethal distending toxin (ctdB), and a multidrug efflux pump (cmeC) being the most notable.