Hp0521 inhibited the virulence of 26,695 strain via regulating CagA expression.

is the number of cag pathogenicity island (cagPAI) family in (), which encoded Cag2 protein. The aim of this study was to investigate the role of on the strain. We constructed the recombinant prokaryotic expression plasmid pET-32a- and pET-32a-. Then, we co-cultured the wild strain 26,695 and strain with GES-1 cells to detect CagA protein transport and IL-8 secretion. We found that mutation increased the expression of and promoted the transportation of CagA protein in GES-1 cells. In addition, we also observed that mutation had no effect on other cagPAI protein stability and the expression of IL-8. Our findings suggested that may down-regulated the expression of cagA, rpoB and inhibited the transportation of CagA protein in GES-1 cells and had no effect on growth.