Differential virulence-gene mRNA expression in coccoid forms of Helicobacter pylori

Biochem Biophys Res Commun. 2001 Jul 13;285(2):530-6. doi: 10.1006/bbrc.2001.5179.


Controversy exists whether coccoid forms of Helicobacter pylori maintain transcriptional and translational processes. The aim of the present study was to investigate mRNA levels in coccoid H. pylori and, if possible, to establish a correlation with the state of nonrandom fragmentation of rRNA in those cells. For that purpose, UreA, UreI, CagA, VacA, SodB, and Hsp60 mRNA levels in bacillary and coccoid forms of H. pylori CCUG 17874(T), H. pylori 26695, and H. pylori J99, respectively, were studied by means of a multiplex reverse-transcription PCR assay and Southern blot analysis of the RT-PCR-amplified products. Nonrandom fragmentation of 23S rRNA was assessed by a recently described assay. Virulence-gene-derived mRNA transcripts were visualized in DNase I-treated RNA preparations. All three strains revealed the presence of different mRNA patterns in bacillary and coccoid forms. Putative promoter sequences similar to the consensus Escherichia coli -10 hexamer TATAAA box were present in all six virulence genes analyzed. Moreover, the decrease seen in mRNA levels during conversion into the coccoid form appeared to correlate with the 23S rRNA nonrandom fragmentation pattern. The present data indicate that modulation of virulence-gene expression is differently regulated in bacillary and coccoid H. pylori.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Bacterial*
  • Bacterial Proteins / genetics*
  • Base Sequence
  • Chaperonin 60 / genetics
  • Gene Expression Regulation, Bacterial*
  • Helicobacter pylori / cytology
  • Helicobacter pylori / genetics*
  • Helicobacter pylori / pathogenicity*
  • Membrane Transport Proteins*
  • Molecular Sequence Data
  • Promoter Regions, Genetic
  • RNA, Bacterial / genetics
  • RNA, Messenger / genetics
  • RNA, Ribosomal, 23S / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Alignment
  • Sequence Homology, Nucleic Acid
  • Superoxide Dismutase / genetics
  • TATA Box
  • Transcription, Genetic*
  • Virulence / genetics


  • Antigens, Bacterial
  • Bacterial Proteins
  • Chaperonin 60
  • Membrane Transport Proteins
  • RNA, Bacterial
  • RNA, Messenger
  • RNA, Ribosomal, 23S
  • UreI protein, Helicobacter pylori
  • VacA protein, Helicobacter pylori
  • cagA protein, Helicobacter pylori
  • SodB protein, Bacteria
  • Superoxide Dismutase