Biological activity of the virulence factor cagA of
Helicobacter pylori
朱永良;郑树;钱可大;方平楚
【期刊名称】《中华医学杂志（英文版）》 【年(卷),期】2004(000)009
【摘要】Background China is one of the countries with the highest incidence of H. Pylori and more than 9090 isolates possessed the cagA gene. This study was to evaluate the biological activity of the H.pylori virulence factor cagA isolated from Chinese patients. Methods cagA DNA fragments were amplified from the genomic DNA and subsequently cloned into the mammalian expression vector for cell transfection and DNA sequencing. cagA protein, phosphorylated-tyrosine cagA and the complex of cagA precipitated with SHP-2 were identified respectively by western blot in the crude cell lysate from conditionally immortalized gastric epithelial cells at 48 hours after transfection with cagA DNA. In addition, the ability of induction of scattering phenotype was examined after transient expression of cagA in AGS cells.rnResults The C-terminal half of cagA contained only one repeated sequence and three tandem five-amino-acid motifs glutamic acid-proline-isoleucine-tyrosine-alanine (EPIYA). Moreover, the amino acid sequence of D2 region in repeated sequence was aspartic acid-phenylanaline-aspartic
acid
(D-F-D)
which
was
significantly
Biological activity of the virulence factor cagA of Helicobacter pylori
