title: Characterization of CagA variable region of Helicobacter pylori isolates from Chinese patients.
abstract: OBJECTIVE
  To characterize the CagA variable region of Helicobacter pylori isolates from Chinese patients.
  
  
  METHODS
  DNA fragments in CagA variable region were amplified and sequenced respectively from genomic DNA of 19 isolates from patients with gastric cancer and 20 isolates from patients with chronic gastritis. The tendency of phosphorylation in tyrosine(s) of CagA proteins was evaluated subsequently by phosphorylation assay in vivo and in vitro respectively.
  
  
  RESULTS
  About 97.44% (38/39) H pylori isolates possessed CagA gene. CagA(+) strains contained 2-4 tandem five-amino-acid motifs EPIYA but only one EPIYA had repeated sequence in CagA variable region in different isolates. There was no significant difference between the number of EPIYA motifs in H pylori from patients with different diseases. However, only tyrosine site in EPIYA within repeated sequence could be phosphorylated by AGS cells in vivo although all tyrosine sites in EPIYA could be phosphorylated in vitro.
  
  
  CONCLUSIONS
  CagA in Chinese has no functional difference in perturbing cellular signal pathway among different H pylori isolates.
authors.affiliation: Department of Gastroenterology, Second Hospital of Zhejiang University College of Medicine, Hangzhou, China.
authors.forename: Yong-Liang
authors.initials: YL
authors.lastname: Zhu
authors.forename: Shu
authors.initials: S
authors.lastname: Zheng
authors.forename: Qin
authors.initials: Q
authors.lastname: Du
authors.forename: Ke-Da
authors.initials: KD
authors.lastname: Qian
authors.forename: Ping-Chu
authors.initials: PC
authors.lastname: Fang
mesh_terms: D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000235:genetics* / Q000378:metabolism*; D044466:Asian People; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010766:Phosphorylation; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D047908:Intracellular Signaling Peptides and Proteins; C080866:cagA protein, Helicobacter pylori; D014443:Tyrosine; C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases