Acid-induced expression of an LPS-associated gene in Helicobacter pylori.
To investigate urease-independent mechanisms by which Helicobacter pylori resists acid stress, subtractive RNA hybridization was used to identify H. pylori genes whose expression is induced after exposure to acid pH. This approach led to the isolation of a gene that encoded a predicted 34.8kDa protein (WbcJ), which was homologous to known bacterial O-antigen biosynthesis proteins involved in the conversion of GDP-mannose to GDP-fucose. An isogenic wbcJ null mutant strain failed to express O-antigen and Lewis X or Lewis Y determinants and was more sensitive to acid stress than was the wild-type strain. Qualitative differences in LPS profiles were observed in H. pylori cells grown at pH 5 compared with pH 7, which suggests that H. pylori may alter its LPS structure in response to acidic pH. This may be an important adaptation facilitating H. pylori colonization of the acidic gastric environment.
McGowan
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Department of Medicine, Vanderbilt University Medical School, and Department of Veterans Affairs Medical Center, Nashville, TN, USA. mcgowacc@ctrvax.vanderbilt.edu
Necheva
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A
Thompson
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Cover
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Blaser
M J
MJ
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D016480:Helicobacter pylori / Q000737:chemistry / Q000235:genetics* / Q000254:growth & development; D006863:Hydrogen-Ion Concentration; D015151:Immunoblotting; D007983:Lewis Blood Group Antigens / Q000096:biosynthesis; D016256:Lewis X Antigen / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000737:chemistry*; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D019081:O Antigens / Q000096:biosynthesis / Q000737:chemistry; D017422:Sequence Analysis, DNA
D001426:Bacterial Proteins; D007983:Lewis Blood Group Antigens; D016256:Lewis X Antigen; C094162:Lewis Y antigen; D008070:Lipopolysaccharides; D019081:O Antigens; C116487:WbcJ protein, Helicobacter pylori