Keith Wilson
Faculty Member
Last active: 11/2/2019

Analysis of Helicobacter pylori cagA promoter elements required for salt-induced upregulation of CagA expression.

Loh JT, Friedman DB, Piazuelo MB, Bravo LE, Wilson KT, Peek RM, Correa P, Cover TL
Infect Immun. 2012 80 (9): 3094-106

PMID: 22710874 · PMCID: PMC3418733 · DOI:10.1128/IAI.00232-12

Helicobacter pylori infection and consumption of a high-salt diet are each associated with an increased risk for the development of gastric cancer. To investigate potential synergism between these factors, we used a global proteomic approach to analyze H. pylori strains cultured in media containing varying salt concentrations. Among the differentially expressed proteins identified, CagA exhibited the greatest increase in expression in response to high salt concentrations. Analysis of 36 H. pylori strains isolated from patients in two regions of Colombia with differing incidences of gastric cancer revealed marked differences among strains in salt-responsive CagA expression. Sequence analysis of the cagA promoter region in these strains revealed a DNA motif (TAATGA) that was present in either one or two copies. Salt-induced upregulation of CagA expression was detected more commonly in strains containing two copies of the TAATGA motif than in strains containing one copy. Mutagenesis experiments confirmed that two copies of the TAATGA motif are required for salt-induced upregulation of CagA expression. In summary, there is considerable heterogeneity among H. pylori strains in salt-regulated CagA expression, and these differences are attributable to variation in a specific DNA motif upstream of the cagA transcriptional start site.

MeSH Terms (19)

Antigens, Bacterial Bacterial Proteins Colombia Culture Media DNA, Bacterial DNA Mutational Analysis Gene Expression Profiling Gene Expression Regulation, Bacterial Helicobacter Infections Helicobacter pylori Humans Male Molecular Sequence Data Promoter Regions, Genetic Proteome Salts Sequence Analysis, DNA Stomach Neoplasms Up-Regulation

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