霍乱弧菌溶原性噬菌体CTXΦ的氯霉素抗性基因标记及诱导

Chloramphenicol resistance marker exchange of lysogenic phage CTXΦ of Vibrio cholerae and its induction

目的 对携带霍乱毒素基因的溶原性噬菌体CTXΦ进行遗传标记 ,以深入研究CTXΦ对霍乱弧菌的转染机制。方法 将CTXΦ基因组中ctxAB的上下游同源序列连接到cat基因的两侧 ,然后通过自杀质粒介导的DNA同源重组技术将霍乱菌株N16 96 1染色体上CTXΦ基因组中的ctxAB基因缺失掉 ,替换以氯霉素抗性基因 ,对CTXΦ基因组进行遗传标记 ,然后用丝裂霉素C诱导这种经抗性基因标记的噬菌体 ,再利用它对古典型霍乱弧菌的转染检测活性。结果 获得了ctxAB缺失、带有cat遗传标记的重组菌株N Φc;诱导出的CTXΦc噬菌体颗粒成功感染了霍乱菌株 1119。结论 N Φc中的CTXΦ带有了氯霉素抗性标记 。

Objective To mark the CTXΦ genome with chloramphenicol acetyltransferase gene ( cat ) and to induce it as a tool to study the CTXΦ′s transduction in V.cholerae . Methods ctxAB gene of CTXΦ on chromosome V. cholerae N16961 was exchanged by cat gene, which was flanked with upstream and downstream fragment of ctxAB , through homologous recombination mediated by the suicide plasmid. The cat marked CTXΦ genome was induced with mitomycin C to test its transfection among classical type V. cholerae strains. Results cat gene replaced ctxAB which integrates on the chromosome, and this cat marked CTXΦ genome, N Φc, can be induced and infected the tested V. cholerae strain. Conclusion We obtained a cat marked CTXΦ and can be used to study the horizontal transfer mechanism of CTXΦ between different V. cholerae strains.