Epigenetic implication of gene-adjacent retroelements in Helicobacter pylori-infected adults

Epigenomics. 2012 Oct;4(5):527-35. doi: 10.2217/epi.12.51.


A chronic inflammatory condition of gastric mucosa can facilitate the influx of new stem cells into the stomach. Epigenetic codes, such as DNA methylation, may be responsible for the stable maintenance of epigenetic phenotypes established in the new stomach-adapted stem cells. A number of hypotheses have been made for the role of CpG-island methylation, which is common in the Helicobacter pylori-infected stomach. However, they could not explain the plausible role of CpG-island methylation in the re-establishment of epigenetic phenotypes. These islands are highly repetitive sequences densely methylated throughout the human genome, the so-called parasitic retroelements, which expand a number of cDNA copies with reverse transcriptase. The densely methylated retroelements adjacent to the host genes can form the transitional-CpG sites around gene-control regions that are barely methylated. This review focuses on the putative role of transitional CpG methylation in the adaptive differentiation of new stem cells in the H. pylori-infected stomach.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Alu Elements*
  • Animals
  • CpG Islands
  • DNA Methylation
  • Epigenesis, Genetic*
  • Gene Expression Regulation, Neoplastic*
  • Genome, Human
  • Helicobacter Infections
  • Helicobacter pylori / genetics*
  • Helicobacter pylori / pathogenicity
  • Humans
  • Intestinal Mucosa / microbiology
  • Intestinal Mucosa / pathology
  • Stem Cells / pathology
  • Stomach / microbiology
  • Stomach Neoplasms / microbiology
  • Stomach Neoplasms / pathology