This Article Full Text Full Text (PDF) An erratum has been published Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ando, T. Articles by Wassenaar, T. M. Search for Related Content PubMed PubMed Citation Articles by Ando, T. Articles by Wassenaar, T. M.

Evolutionary History of hrgA, Which Replaces the Restriction Gene hpyIIIR in the hpyIII Locus of Helicobacter pylori

First Department of Internal Medicine, Nagoya University School of Medicine, Nagoya, Japan,¹ Departments of Medicine and Microbiology, New York University School of Medicine,² Department of Veterans Affairs Medical Center, New York, New York,³ Molecular Microbiology and Genomics Consultants, Zotzenheim, Germany⁴

Received 24 June 2002/ Accepted 1 October 2002

A recently identified Helicobacter pylori gene, hrgA, was previously reported to be present in 70 (33%) of 208 strains examined (T. Ando, T. M. Wassenaar, R. M. Peek, R. A. Aras, A. I. Tschumi, L.-J. Van Doorn, K. Kusugami, and M. J. Blaser, Cancer Res. 62:2385-2389, 2002). Sequence analysis of nine such strains indicated that in each strain hrgA replaced hpyIIIR, which encodes a restriction endonuclease and which, together with the gene for its cognate methyltransferase, constitutes the hpyIII locus. As a consequence of either the hrgA insertion or independent mutations, hpyIIIM function was lost in 11 (5%) of the 208 strains examined, rendering chromosomal DNA sensitive to MboI digestion. The evolutionary history of the locus containing either hpyIII or hrgA was reconstructed. By homologous recombination involving flanking sequences, hrgA and hpyIIIR can replace one another in the hpyIII locus, and there is simultaneous replacement of several flanking genes. These findings, combined with the hpyIM/iceA2 locus discovered previously, suggest that the two most strongly conserved methylase genes of H. pylori, hpyIIIM and hpyIM, are both preceded by alternative genes that compete for presence at their loci.

This article has been cited by other articles:

• Ghose, C., Perez-Perez, G. I., van Doorn, L. J., Dominguez-Bello, M. G., Blaser, M. J. (2005). High Frequency of Gastric Colonization with Multiple Helicobacter pylori Strains in Venezuelan Subjects. J. Clin. Microbiol. 43: 2635-2641 [Abstract] [Full Text]