幽门螺杆菌vacA基因的克隆和序列分析

Cloning and sequencing of vacuolating cytotoxin A gene from Helicobacter pylori

空泡毒素是幽门螺杆菌产生的已知的唯一蛋白毒素,该毒素与感染者胃肠上皮损伤和溃疡形成密切相关,同时也是幽门螺杆菌免疫预防和免疫治疗的重要候选组分。从幽门螺杆菌NCTC11637染色体DNA中经PCR方法获得了2.9kb的该基因成熟肽全长序列,将该基因克隆至载体pET22b+,经PCR扩增和酶切鉴定后序列分析表明,该基因与已知序列完全一致。

The vacuolating cytotoxin A (VacA)is a unique proteinous cytotoxin producted by Helicobacter pylori that showed no striking primary sequence homology with other known bacterial toxins.The cytotoxin is an important factor in the pathogenesis of Helicobacter pylori,which induces vacuolation of gastric epithelial cells and plays an important role in gastric epithelial necrosis and peptic ulceration.VacA also is an important candidate vaccine anti-gen of prophylactic and therapeutic immunisation.A total sequence of mature peptide of vacuolating cytotoxin A gene was gotten with PCR method from the genome of standard Helicobacter pylori NCTC11637.The gene was ligated with pET22b+vector and recombinant plasmid pET-vacA was constructed.After identified by PCR amplifica-tion and enzyme digestion,sequencing indicated that the cloned gene sequence is the same as the published se-quence.