SYNTHESIS OF CHOLERA-TOXIN IS POSITIVELY REGULATED AT THE TRANSCRIPTIONAL LEVEL BY TOXR
SYNTHESIS OF CHOLERA-TOXIN IS POSITIVELY REGULATED AT THE TRANSCRIPTIONAL LEVEL BY TOXR
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DOI：
10.1073/pnas.81.11.3471
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发表时间：
1984-01-01
期刊：
影响因子：
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通讯作者：
MEKALANOS, JJ
中科院分区：
文献类型：
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作者：
MILLER, VL;MEKALANOS, JJ
克隆了来自霍乱弧菌的控制霍乱毒素转录的正调控基因（toxR）。这是通过首先构建由 lacZ 基因与霍乱毒素操纵子 ctxAB 启动子融合的基因融合体来完成的。该操纵子融合体用于筛选霍乱弧菌基因组文库，寻找可激活大肠杆菌中 ctx 启动子的基因。该方法能够鉴定出一种基因 toxR，该基因可将 ctx 表达增加 100 倍以上。互补分析表明，霍乱弧菌569B 的某些低产毒素突变体可能在toxR 基因中存在突变。 Southern印迹分析表明所有霍乱弧菌，包括非产毒菌株，都具有toxR基因。非产毒菌株缺乏霍乱毒素的结构基因以及与较大的 7 千碱基 ctx 遗传元件相关的序列。
A positive regulatory gene (toxR) from Vibrio cholerae that controls cholera toxin transcription was cloned. This was done by first constructing a genetic fusion consisting of the lacZ gene fused to the promoter of the cholera toxin operon ctxAB. This operon fusion was used to screen a V. cholerae genomic library for genes that could activate the ctx promoter in Escherichia coli. This method allowed the identification of a gene, toxR, that increases ctx expression by > 100-fold. Complementation analysis indicated that certain hypotoxinogenic mutants of V. cholerae 569B probably have mutations in the toxR gene. Southern blot analysis suggests that all V. cholerae, including nontoxinogenic strains, have the toxR gene. Nontoxinogenic strains lack the structural genes for cholera toxin and also sequences associated with the larger 7-kilobase ctx genetic element.