伤寒沙门氏菌肠毒素基因突变株的构建

MUTANT CONSTRUCTION OF SALMONELLA TYPHI ENTEROTOXIN GENE

目的 为探讨伤寒沙门氏菌肠毒素的致病机理。方法 根据已知的鼠伤寒沙门氏菌的肠毒素基因序列， 设计 Ｐ Ｃ Ｒ 引物， 扩增并克隆了伤寒沙门氏菌的肠毒素结构基因。双酶切造成部分序列缺失， 亚克隆于自杀质粒后， 通过电穿孔转化， 同源重组替换野生型肠毒素基因。结果 Ｐ Ｃ Ｒ 及序列分析证实， 缺失突变株的肠毒素基因缺失４０３ 个碱基。经血清学鉴定， 该突变株保持母系菌株的 Ｖｉ 抗原表型。 结论 该突变株的构建为研究肠毒素基因在至于致病机制中的作用奠定了基础。

Aim\ Mutant of S typhi enterotoxin gene was constructed to understand the pathogenic mechanisms of enterotoxin from S typhi.Methods\ The structure gene of S typhi was amplified and cloned by PCR with the primers derived from S typhimurium.Some of the bases were deleted by double digestion.Wild type gene was replaced through homologous recombination with a suicide vector containing the deleted gene.Results\ A 403 bp deletion of the enterotoxin gene was confirmed by PCR and sequencing analysis.The Vi antigen phenotype of the mutant did not change in contrast to wild strain with serological method. Conclusion\ The construction of mutant of S typhi lays a fundation for the study of pathogenic mechanism of enterotoxin gene.