表达CtxB的非抗生素标记载体的构建

Construction of the CtxB-expressing vector with the non-antibiotic gene marker

目的构建用于表达CtxB的非抗生素基因作为选择标记的载体。方法用PCR从质粒pMT999中,扩增获得2.9kb的汞抗性基因与pBR322的复制起始区ori相连得到重组质粒pBRH02。然后将含有β-内酰胺酶启动子的CtxB基因插入pBRH02中,构建表达质粒pBRC09。结果pBRC09经转化大肠杆菌、痢疾杆菌,用GM1-ELISA均检测到CtxB在上述菌株中的有效表达。结论利用汞抗性基因和pBR322的复制起始区,成功地构建成以非抗生素为选择标记的表达CtxB的重组质粒。

Aim To construct a CtxB -expressing vect or carrying a non -antibiotic gene marker.Methods The mercuric -resistance gene with a tength of 2.9kb was obtained from pla smid pMT999by PCR.It was ligated to origin of replication of p BR322,resulting the recombinant plasmid pBRH02.Then the expression vector was constructed by insert-ing the CtxB gene withβ-lactamase promoter into pBRH02.Results After pBRC09was transformed into E.coli and Shigella spp.,the effective expression of CtxB in them was detected by GM1-ELISA.Conclusion Using the mercuric resistance gene a nd origin of replication of pBR322,the recombinant plasmid,which expr esses CtxB and carries a non -an-tibiotic gene marker,was successfu lly constructed.