Characterization of the low-pH responses of Helicobacter pylori using genomic DNA arrays

• Published in: Microbiology (Society for General Microbiology) Vol. 147; no. 8; pp. 2285 - 2292
• Main Authors: Allan, Elaine, Clayton, Christopher L, McLaren, Alistair, Wallace, Donald M, Wren, Brendan W
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.08.2001; Society for General Microbiology
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biological and medical sciences; cagA gene; DNA arrays; DNA, Complementary; Fundamental and applied biological sciences. Psychology; Gene Expression Profiling; Gene Expression Regulation, Bacterial; Genetics; Genome, Bacterial; Helicobacter pylori; Helicobacter pylori - genetics; Helicobacter pylori - growth & development; Helicobacter pylori - metabolism; Humans; Hydrogen-Ion Concentration; Microbiology; Nucleic Acid Hybridization - methods; Oligonucleotide Array Sequence Analysis; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; RNA, Bacterial - analysis; secF gene; Ability; Human; Spirillales; Genomics; Spirillaceae; Hybridization; Characterization; Polymerase chain reaction; Complementary DNA; Gene; Helicobacter pylori; Pathogenic; pH; Bacteria; Environment; Population dynamics; Population density
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/00221287-147-8-2285

Pathogen Molecular Biology and Biochemistry Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK 1 Department of Genomics, Glaxo Wellcome Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK 2 Author for correspondence: Brendan W. Wren. Tel: +44 20 7927 2288. Fax: +44 20 7636 8739. e-mail: brendan.wren{at}lshtm.ac.uk Helicobacter pylori is unique among bacterial pathogens in its ability to persist in the acidic environment of the human stomach. To identify H. pylori genes responsive to low pH, the authors assembled a high-density array of PCR-amplified random genomic DNA. Hybridization of radiolabelled cDNA probes, prepared using total RNA from bacteria exposed to buffer at either pH 4·0 or pH 7·0, allowed both qualitative and quantitative information on differential gene expression to be obtained. A previously described low-pH-induced gene, cagA , was identified together with several novel genes that may have relevance to the survival and persistence of H. pylori in the gastric environment. These include genes encoding enzymes involved in LPS and phospholipid synthesis and secF , encoding a component of the protein export machinery. A hypothetical protein unique to H. pylori (HP0681) was also found to be acid induced. Genes down-regulated at pH 4·0 include those encoding a sugar nucleotide biosynthesis protein, a flagellar protein and an outer-membrane protein. Differential gene expression was confirmed by total RNA slot-blot hybridization. Keywords: acid-induced gene expression, genomic DNA array, pathogenicity