title: Promoter analysis of Helicobacter pylori genes with enhanced expression at low pH.
abstract: To identify Helicobacter pylori genes with expression that is enhanced under low pH conditions, we used subtractive hybridization methodology. We identified 28 acid-induced genes, of which 18 have known or putative functions. Six pairs of genes were co-transcribed. Primer extension analysis identified single or multiple transcriptional start points (tsp) for 14 of the 22 loci. Sequence analysis of the -10 regions upstream of the tsps revealed consensus motifs for multiple RNA polymerase sigma factors present in H. pylori (sigma80, sigma54 and sigma28). No sequences resembling the -35 Escherichia coli consensus sequence (TTGACA) were present upstream of any of the genes. Both increased gene transcription and decreased mRNA decay contribute to the observed increase in H. pylori transcript abundance at acid pH. These studies document the complex response of H. pylori to environmental pH changes, and provide insight into mechanisms used for intragastric survival.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, A-3310 Medical Center North, Vanderbilt University School of Medicine, Nashville, TN 37232-2605, USA. c.mcgowan@vanderbilt.edu
authors.forename: Catherine C
authors.initials: CC
authors.lastname: McGowan
authors.forename: Antoaneta S
authors.initials: AS
authors.lastname: Necheva
authors.forename: Mark H
authors.initials: MH
authors.lastname: Forsyth
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Cover
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Blaser
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial; D016480:Helicobacter pylori / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D015854:Up-Regulation
chemical_list: D001426:Bacterial Proteins; D012333:RNA, Messenger