Brief Reports
Copyright ©The Author(s) 2004. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 1, 2004; 10(23): 3511-3513
Published online Dec 1, 2004. doi: 10.3748/wjg.v10.i23.3511
Cloning and sequencing of cagA gene fragment of Helicobacter pylori with coccoid form
Ke-Xia Wang, Xue-Feng Wang
Ke-Xia Wang, Xue-Feng Wang, School of Medicine, Anhui University of Science &Technology Huainan 232001, Anhui Province, China
Author contributions: All authors contributed equally to the work.
Supported by Natural Science Foundation of the Education Department of Anhui Province, China No.2003kj111
Correspondence to: Dr. Ke-Xia Wang, Department of Etiology and Immunology, School of Medicine, Anhui University of Science & Technology, Huainan 232001, Anhui Province, China.
Telephone: +86-554-6658770 Fax: +86-554-6662469
Received: October 20, 2003
Revised: November 22, 2003
Accepted: December 8, 2003
Published online: December 1, 2004

AIM: To clone and sequence the cagA gene fragment of Helicobacter pylori (H pylori) with coccoid form.

METHODS: H pylori strain NCTC11637 were transformed to coccoid form by exposure to antibiotics in subinhibitory concentrations. The coccoid H pylori was collected. cagA gene of the coccoid H pylori strain was amplified by PCR. After purified, the target fragment was cloned into plasmid pMD-18T. The recombinant plasmid pMD-18T-cagA was transformed into E.coli JM109. Positive clones were screened and identified by PCR and digestion with restriction endonucleases. The sequence of inserted fragment was then analysed.

RESULTS: cagA gene of 3 444 bp was obtained from the coccoid H pylori genome DNA. The recombinant plasmid pMD-18T-cagA was constructed, then it was digested by BamH I+Sac I, and the product of digestion was identical with the predicted one. Sequence analysis showed that the homology of coccoid and the reported original sequence H pylori was 99.7%.

CONCLUSION: The recombinant plasmid containing cagA gene from coccoid H pylori has been constructed successfully. The coccoid H pylori contain completed cagA gene, which may be related to pathogenicity of them.

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