Cloning and Expression of Escherichia coli O157 Z4182 Gene

Six strains of enterohemorrhagic Escherichia coli(EHEC) O157,seven strains of non-O157 Escherichia coli,two strains of Salmonella,two strains of Shigella,and two strains of Yersinia were detected by polymerase chain reaction(PCR) using a pair of primers designed on the Z4182 ge ne sequence of EHEC O157 and ended with NcoⅠ and XhoⅠ restriction endo nucleases sites at their 5′ends.The results indicated that all EHEC O157 strain s,one STEC strain,1 EAggEC strain and 1 ETEC strain were also positive for Z4182 gene.The PCR products amplified from EHEC strain 94H and the vector pET28a(+) w ere digested with restriction endonucleases NcoⅠ and XhoⅠ,ligated with T 4 DNA ligase and transferred into bacterial host LE392.The recombinant plasm id was further transferred into host strain BL21.Expression protein was detected b y SDS-PAGE.The induction tests with IPTG suggested that the 3 to 5 hours was th e most efficient for the expression of Z4182 gene.