In vitro and in vivo characterization of three major dadAX promoters in Escherichia coli that are regulated by cyclic AMP-CRP and Lrp
In vitro and in vivo characterization of three major dadAX promoters in Escherichia coli that are regulated by cyclic AMP-CRP and Lrp
复制标题
大肠杆菌中受环 AMP-CRP 和 Lrp 调节的三个主要 dadAX 启动子的体外和体内表征
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
Martin Freundlich
中科院分区：
文献类型：
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作者：
Jizu Zhi;E. Mathew;Martin Freundlich
摘要我们以前已经证明，大肠杆菌的dadAX操纵子表达多个转录本，这些转录本被亮氨酸反应调节蛋白(LRP)抑制。在这里，我们使用定点突变和体外和体内转录实验来表明，三个主要的DAD转录本中的每一个都需要一个特定的启动子。这些启动子P1-P3重叠，并在体内受到环化AMP-CRP的正调节。DNase I足迹实验定位了该区域的两个CRP结合位点：位于P1-P3上游的CRP1和位于启动子内的CRP2。每个位点的定点突变提供了证据，证明CRP1是环状AMP-CRP在体内和体外影响DAD表达所必需的，而CRP2可能在这一过程中几乎或根本不起作用。
Abstract We have shown previously that the dadAX operon of Escherichia coli expresses multiple transcripts, which are repressed by leucine-responsive regulatory protein (Lrp). Here we used site-directed mutagenesis and in vitro and in vivo transcription assays to show that each of the three major dad transcripts requires a specific promoter. These promoters, P1-P3, overlap and are positively regulated in vivo by cyclic AMP-CRP. DNase I footprinting experiments localized two CRP binding sites in this region: CRP1, which is positioned upstream of P1-P3, and CRP2, which is located within the promoters. Site-directed mutagenesis of each site provided evidence that CRP1 is necessary for the effects of cyclic AMP-CRP on dad expression in vivo and in vitro, and that CRP2 probably plays little or no role in this process.
影响因子：
14.9
作者：
HEMSLEY, A;ARNHEIM, N;GALAS, DJ
通讯作者：
GALAS, DJ