PCR-RFLP and bioinformatic assay of urease B gene from different helicobacter pylori strains / 医学研究生学报

ABSTRACT

Objective:To analyze the polymorphism of urease B gene(ureB) from different Hp strains. Methods:The sequences of ureB gene from 14 different Hp strains were amplified by PCR to analyze PCR-RFLP with HaeⅢ digestion.At the same time,the sequence of ureB gene was analyzed with biochemical software to compare the homology of nucleotide and amino acid sequence and to profile the phylogenetic tree. Results: The results of 1.7 kb ureB gene digested with HaeⅢ showed there were 2-5 band types in 14 different Hp strains and formed five distinct RFLP types.The two reference strains had the same RFLP type as 3 clinical isolates while the other clinical isolates and 3 isolates from animal model belong to 4 different RFLP types respectively.The nucleotide sequences and putative amino acide sequences of Hp ureB were compared.The various ureB sequences had high homologies(more than 96.6% and 98% in nucleotide sequences and amino acide sequences respectively) among 14 Hp strains.Particularly,there was the highest homologies(100%) between CCS9801、CCS9806、M3 and M10.Phylogenetic tree analysis showed that two reference strains and other isolates from clinical patients and Hp-infected mice model were located in two different lineage respectively in phylogenetic tree of nucleotide sequences while there were some variance in phylogenetic tree of amino acide sequences. Conclusion: Hp ureB was high conserved and homologous in the gene level as well as in the protein level.