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Mutation of cytotoxin-associated gene A affects expressions of antioxidant proteins of Helicobacter pylori

Author(s): Zhi-Gang Huang, Guang-Cai Duan, Qing-Tang Fan, Wei-Dong Zhang, Chun-Hua Song, Xue-Yong Huang, Rong-Guang Zhang

Journal: World Journal of Gastroenterology
ISSN 1007-9327

Volume: 15;
Issue: 5;
Start page: 599;
Date: 2009;
Original page

Keywords: Helicobacter pylori | Cytotoxin-associated gene A | Knock-out | Antioxidant protein | Two-dimensional electrophoresis

AIM: 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_ΔcagA (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.CONCLUSION: 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.
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