Cloning and analysis of iceA gene of isolated Helicobacter pylori

Objective To clone the gene(iceA)induced by contact with epithelium of Helico bacter pylori MEL-Hp27 isolated in China and to analyze its sequence.Methods Prmiers were designed according to the sequences located in the upstreamor down-stream of the iceA gene.The DNA was amplified by PCR and the fragment was inserted into plasmid pMD19-T for nucleotide sequencing.The bioinformatics analysis was carried out with databases o f Blastor NCBI and soft-ware of DNA star,Clusta lW and MEGA 4.0.Results The iceA gene of Hp27 stra in was succe ssfully cloned.The PCR product was about 790bp.The recom binant plasmid pMD19-T-iceA was digested with one restriction enzyme to produce a 3820bp DNA fragment and digested with two enzymes to produce 3000bp and 820bp DNA fragments.Sequence analysis showed that the iceA gene of MEL-Hp27 has more than 85% of homology with American H.pylori strains and less than 70% of homology with Japanese or Indian H.pylori strains.The-10 box was located in the up-stream of iceA gene and the distance from ATG is 17bp.The SD sequence is located in the up-stream of iceA gene and the distance from ATG is 7bp.There are two ava riable numbers of tandem repeats bewteen ATG and the up-stream gene cysE.There are differences in the characters of the gene bewteen Hp27 strains and other Helico bacter pylori strains from other regions.Conclusion The iceA gene of Helicobacter pylori MEL-Hp27 was successfully cloned.There are differences among Helicobacter pylori strains from different regions.