Methylation Motifs in Promoter Sequences May Contribute to the Maintenance of a Conserved m5C Methyltransferase in Helicobacter pylori

Bowen Meng,Winsen Wijaya,Jan Mrázek,Timothy R Hoover,Naomi Epp

doi:10.3390/microorganisms9122474

Bowen Meng, Winsen Wijaya + Show 3 more

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https://doi.org/10.3390/microorganisms9122474

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Journal: Microorganisms	Publication Date: Nov 30, 2021
Citations: 3	License type: CC BY 4.0

Affiliation: University of Georgia

Abstract

DNA methylomes of Helicobacter pylori strains are complex due to the large number of DNA methyltransferases (MTases) they possess. H. pylori J99 M.Hpy99III is a 5-methylcytosine (m5C) MTase that converts GCGC motifs to Gm5CGC. Homologs of M.Hpy99III are found in essentially all H. pylori strains. Most of these homologs are orphan MTases that lack a cognate restriction endonuclease, and their retention in H. pylori strains suggest they have roles in gene regulation. To address this hypothesis, green fluorescent protein (GFP) reporter genes were constructed with six putative promoters that had a GCGC motif in the extended −10 region, and the expression of the reporter genes was compared in wild-type H. pylori G27 and a mutant lacking the M.Hpy99III homolog (M.HpyGIII). The expression of three of the GFP reporter genes was decreased significantly in the mutant lacking M.HpyGIII. In addition, the growth rate of the H. pylori G27 mutant lacking M.HpyGIII was reduced markedly compared to that of the wild type. These findings suggest that the methylation of the GCGC motif in many H. pylori GCGC-containing promoters is required for the robust expression of genes controlled by these promoters, which may account for the universal retention of M.Hpy99III homologs in H. pylori strains.

Highlights

H. pylori strains grown for 3–4 days on tryptic soy agar (TSA), as described above, were used to inoculate 15 mL of Brain Heart Infusion (BHI) supplemented with 5% heat-inactivated horse serum in a 100 mL serum vial with a glass tube sidearm that fit into a Klett colorimeter
Play a critical role in H. pylori biology, as loss of the MTase in the H. pylori strains J99 and BCM-300 resulted in the altered expression of several genes in the two strains, many of which are involved in cellular functions required for host colonization [22]
While the altered expression of some of these genes was likely due to indirect effects, results from the study by Estibariz and co-workers indicated that the GCGC motif in the extended

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Helicobacter pylori, a member of the phylum Campylobacterota, which was formerly known as the subphylum Epsilonproteobacteria [1], colonizes the stomach of about half the human population worldwide [2,3]. Infection of the gastric mucosa by H. pylori is the major factor for peptic ulcer disease and chronic gastritis, and a major risk factor for gastric cancer and mucosa-associated lymphoid tissue lymphoma [4–6]. Several factors facilitate host colonization by H. pylori, including urease, catalase, and motility [7–9]

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