Brief Reports
Copyright ©2005 Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 14, 2005; 11(6): 880-884
Published online Feb 14, 2005. doi: 10.3748/wjg.v11.i6.880
Characterization of CagA variable region of Helicobacter pylori isolates from Chinese patients
Yong-Liang Zhu, Shu Zheng, Qin Du, Ke-Da Qian, Ping-Chu Fang
Yong-Liang Zhu, Qin Du, Ke-Da Qian, Department of Gastroenterology, Second Hospital of Zhejiang University College of Medicine, Hangzhou 310009, Zhejiang Province, China
Shu Zheng, Cancer Institute, Second Hospital of Zhejiang University College of Medicine, Hangzhou 310009, Zhejiang Province, China
Ping-Chu Fang, Department of Microbiology, Zhejiang University College of Medicine, Hangzhou 310009, Zhejiang Province, China
Author contributions: All authors contributed equally to the work.
Supported by the National High Technology Research and Development Program of China, No. 2001AA227111
Correspondence to: Professor Shu Zheng, Jiefang road 88#, Hangzhou 310009, Zhejiang Province, China. zhengshu@zju.edu.cn
Telephone: +86-571-87783868
Received: January 9, 2004
Revised: January 11, 2004
Accepted: February 21, 2004
Published online: February 14, 2005
Abstract

AIM: 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.

CONCLUSION: CagA in Chinese has no functional difference in perturbing cellular signal pathway among different H pylori isolates.

Keywords: Helicobacter pylori, cag pathogencity island, CagA, Tyrosine phosphorylation