Restriction-modification systems may be associated with Helicobacter pylori virulence

Takafumi Ando, Kazuhiro Ishiguro, Osamu Watanabe, Nobuyuki Miyake, Tsuyoshi Kato, Satoshi Hibi, Shunya Mimura, Masanao Nakamura, Ryoji Miyahara, Naoki Ohmiya, Yasumasa Niwa, Hidemi Goto

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Restriction-modification (R-M) systems are exclusive to unicellular organisms and ubiquitous in the bacterial world. Bacteria use R-M systems as a defense against invasion by foreign DNA. Analysis of the genome sequences of Helicobacter pylori strains 26 695 and J99 identified an extraordinary number of genes with homology to R-M genes in other bacterial species. All H. pylori strains possess their own unique complement of active R-M systems. All of the methylases that have been studied so far were present in all major human population groupings, suggesting that their horizontal acquisition pre-dated the separation of these populations. The two most strongly conserved methylase genes of H. pylori, hpy IM and hpy IIIM, are both preceded by alternative genes that compete for presence at their loci, and furthermore these genes may be associated with H. pylori pathogenicity. Further study should investigate the roles of H. pylori R-M systems.

Original languageEnglish
Pages (from-to)S95-S98
JournalJournal of Gastroenterology and Hepatology (Australia)
Issue numberSUPPL. 1
Publication statusPublished - 05-2010
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Hepatology
  • Gastroenterology


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