Helicobacter pylori cagA EPIYA motif polymorphism in Iranian patients with gastric disorders

Helicobacter pylori CagA is the first bacterial oncoprotein to be identified in relation to human gastric cancer. The tyrosine phosphorylation site of CagA is characterized by the presence of a unique Glu-Pro-Ile-Tyr-Ala (EPIYA) motif, which is present in multiple numbers in the carboxy terminal region of the protein. Four distinct EPIYA segments, A to D, have been identified, that are important determinants of the virulence of CagA in H. pylori infections. The aim of this study was to determine the polymorphism of EPIYA segments in an Iranian population. Methods A total of 71 isolates from patients with different gastro duodenal disorders were studied. Genotyping of the cagA variable EPIYA motif was determined by polymerase chain reaction and sequencing for all the cagA positive isolates. The resulting DNA sequences were translated in frame and analyzed using Gene Runner software. Results Out of 44 cagA positive isolates, the EPIYA motifs of ABC (29 isolates), ABCC (3 isolates), AC (2 isolates), C (2 isolates), ABCCC (one isolate), ACC (one isolate); and the mixed types (6 isolates) were detected. The study of the deduced protein sequences confirmed that there were no East Asian type EPIYA-D sequences among the studied Iranian isolates. Conclusion The structure of the 3′ region of the cagA gene (which contains EPIYA motifs) in our Iranian isolates is similar to Europe, North America and Australia which called Western type (EPIYA C) ,which is in contrast to Asian countries such as Japan that Eastern type cagA (EPIYA D) is dominant.

Keywords:

Helicobacter pylori , cagA , EPIYA motif , polymorphism