Heterogeneity in levels of vacuolating cytotoxin gene (vacA) transcription among Helicobacter pylori strains

M. H. Forsyth, J. C. Atherton, M. J. Blaser, T. L. Cover

Research output: Contribution to journalArticle

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Abstract

Broth culture supernatants from Tox+ Helicobacter pylori strains induce vacuolation of HeLa cells in vitro and contain VacA in concentrations that are higher than those found in supernatants from Tox- H. pylori strains. To investigate the basis for this phenomenon, we analyzed the transcription of the vacuolating cytotoxin gene (vacA) in eight Tox+ strains (each with a type s1/m1 vacA genotype) and nine Tox- strains (each with a type s2/m2 vacA genotype). Most of the Tox+ and Tox- strains tested used the same vacA transcriptional start point, but Tox+ strains yielded significantly stronger primer extension signal intensities than did Tox- strains (mean densitometry values of 15.8 ± 1.9 versus 8.9 ± 1.7, P = 0.0016). Correspondingly, when we introduced vacA:: xylE transcriptional fusions into the chromosomes of a Tox+ strain (60190) and a Tox- strain (86-313), the level of XylE activity in 60190 vacA::xylE was about 30-fold higher than that in 86-313 vacA::xylE. Sequence analysis and promoter exchange experiments indicated that the different levels of vacA transcription in these two strains cannot be explained solely by a difference in promoter strength. These data indicate that Tox+ and Tox- H. pylori strains typically differ not only in the VacA amino acid sequence but also in the level of vacA transcription.

Original languageEnglish (US)
Pages (from-to)3088-3094
Number of pages7
JournalInfection and immunity
Volume66
Issue number7
StatePublished - Jul 1 1998

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Cytotoxins
Helicobacter pylori
Genotype
Genes
Densitometry
HeLa Cells
Sequence Analysis
Amino Acid Sequence
Chromosomes

All Science Journal Classification (ASJC) codes

  • Infectious Diseases
  • Parasitology
  • Microbiology
  • Immunology

Cite this

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title = "Heterogeneity in levels of vacuolating cytotoxin gene (vacA) transcription among Helicobacter pylori strains",
abstract = "Broth culture supernatants from Tox+ Helicobacter pylori strains induce vacuolation of HeLa cells in vitro and contain VacA in concentrations that are higher than those found in supernatants from Tox- H. pylori strains. To investigate the basis for this phenomenon, we analyzed the transcription of the vacuolating cytotoxin gene (vacA) in eight Tox+ strains (each with a type s1/m1 vacA genotype) and nine Tox- strains (each with a type s2/m2 vacA genotype). Most of the Tox+ and Tox- strains tested used the same vacA transcriptional start point, but Tox+ strains yielded significantly stronger primer extension signal intensities than did Tox- strains (mean densitometry values of 15.8 ± 1.9 versus 8.9 ± 1.7, P = 0.0016). Correspondingly, when we introduced vacA:: xylE transcriptional fusions into the chromosomes of a Tox+ strain (60190) and a Tox- strain (86-313), the level of XylE activity in 60190 vacA::xylE was about 30-fold higher than that in 86-313 vacA::xylE. Sequence analysis and promoter exchange experiments indicated that the different levels of vacA transcription in these two strains cannot be explained solely by a difference in promoter strength. These data indicate that Tox+ and Tox- H. pylori strains typically differ not only in the VacA amino acid sequence but also in the level of vacA transcription.",
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Heterogeneity in levels of vacuolating cytotoxin gene (vacA) transcription among Helicobacter pylori strains. / Forsyth, M. H.; Atherton, J. C.; Blaser, M. J.; Cover, T. L.

In: Infection and immunity, Vol. 66, No. 7, 01.07.1998, p. 3088-3094.

Research output: Contribution to journalArticle

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T1 - Heterogeneity in levels of vacuolating cytotoxin gene (vacA) transcription among Helicobacter pylori strains

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AU - Blaser, M. J.

AU - Cover, T. L.

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