Cloning and sequencing of cagA gene fragment of Helicobacter pylori with coccoid form.
OBJECTIVE
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%.


CONCLUSIONS
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.
Wang
Ke-Xia
KX
School of Medicine, Anhui University of Science and Technology, Huainan 232001, Anhui Province, China. kexiawang2003@yahoo.com.cn
Wang
Xue-Feng
XF
D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D016480:Helicobacter pylori / Q000166:cytology / Q000235:genetics* / Q000472:pathogenicity*; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000235:genetics; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D014774:Virulence
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D011994:Recombinant Proteins; C080866:cagA protein, Helicobacter pylori