Full sequence of cagA gene and characteristics of cagA protein in five Helicobacter pylori strains in patients from Ho Chi Minh city

ABSTRACT

Background: Helicobacter pylori (H. pylori) strains with positive cagA gene can induce an advanced severe condition of atrophic gastritis and a higher risk of gastric carcinoma than those without cagA gene. Objective: To carry out the full sequence of cagA gene and preliminary analysis, classify cagA protein in H. pylori strains in Vietnamese patients. Subjects and method: 5 patients with H. pylori strains from Ho Chi Minh city were enrolled in the study. H. pylori was cultured and determined by PCR before sequencing full cagA gene. Analyzing cagA gene and constructing phylogenetic tree using biometrics and bioinformatics software. Results: The length of open reading frame of cagA gene of H. pylori strains in Vietnamese patients was 3480-3588 base-pairs, the number of amino acid in relavant cagA protein was 1159-1195 amino acids and all cagA protein molecules belonged to East Asian cagA, none of them was Western cagA. Even with the same classification of East Asian cagA, the Japanese H. pylori strains and Vietnamese strains were located in different cluster in phylogenetic tree. Conclusion: The study suggested that H. pylori cagA proteins in patients from Ho Chi Minh city belonged to East Asian cagA.