title: Mutation of cytotoxin-associated gene A affects expressions of antioxidant proteins of Helicobacter pylori.
abstract: OBJECTIVE
  To determine if disruption of the cagA gene of Helicobacter pylori (H pylori) has an effect on the expression of other proteins at proteome level.
  
  
  METHODS
  Construction of a cagA knock out mutant Hp27_Delta cagA (cagA(-)) via homologous recombination with the wild-type strain Hp27 (cagA(+)) as a recipient was performed. The method of sonication-urea-CHAPS-DTT was employed to extract bacterial proteins from both strains. Soluble proteins were analyzed by two-dimensional electrophoresis (2-DE). Images of 2-DE gels were digitalized and analyzed. Only spots that had a statistical significance in differential expression were selected and analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS). Biological information was used to search protein database and identify the biological function of proteins.
  
  
  RESULTS
  The proteome expressions between wild-type strain and isogenic mutant with the cagA gene knocked-out were compared. Five protein spots with high abundance in bacteria proteins of wild-type strains, down-regulated or absently expressed in bacteria proteins of mutants, were identified and analyzed. From a quantitative point of view, the identified proteins are related to the cagA gene and important antioxidant proteins of H pylori, including alkyl hydroperoxide reductase (Ahp), superoxide dismutase (SOD) and modulator of drug activity (Mda66), respectively, suggesting that cagA is important to maintain the normal activity of antioxidative stress and ensure H pylori persistent colonization in the host.
  
  
  CONCLUSIONS
  cagA gene is relevant to the expressions of antioxidant proteins of H pylori, which may be a novel mechanism involved in H pylori cagA pathogenesis.
authors.affiliation: Department of Epidemiology, College of Public Health, Zhengzhou University, Zhengzhou 450001, Henan Province, China.
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Huang
authors.forename: Guang-Cai
authors.initials: GC
authors.lastname: Duan
authors.forename: Qing-Tang
authors.initials: QT
authors.lastname: Fan
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Zhang
authors.forename: Chun-Hua
authors.initials: CH
authors.lastname: Song
authors.forename: Xue-Yong
authors.initials: XY
authors.lastname: Huang
authors.forename: Rong-Guang
authors.initials: RG
authors.lastname: Zhang
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification; D001427:Bacterial Toxins / Q000235:genetics*; D017931:DNA Primers; D015180:Electrophoresis, Gel, Two-Dimensional; D005756:Gastritis / Q000382:microbiology / Q000473:pathology; D015964:Gene Expression Regulation, Bacterial; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans; D010449:Peptide Mapping; D020543:Proteome / Q000235:genetics*; D015183:Restriction Mapping; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D017931:DNA Primers; D020543:Proteome; C080866:cagA protein, Helicobacter pylori