Regulation of the Escherichia coli lrp gene.
Regulation of the Escherichia coli lrp gene.
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大肠杆菌 lrp 基因的调节。
DOI：
10.1128/jb.176.7.1831-1839.1994
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发表时间：
1994
影响因子：
3.2
通讯作者：
Calvo,JM
中科院分区：
文献类型：
--
作者：
Wang,Q;Wu,J;Friedberg,D;Plakto,J;Calvo,JM
Lrp（leucine-responsive regulatory protein）是大肠杆菌中一种主要的调控蛋白，它对许多操纵子的表达具有负调控和正调控作用。这项工作涉及到一个表征的lrp，基因编码Lrp。核苷酸测序确定lrp和trxB（编码硫氧还蛋白还原酶）的编码区相隔543 bp，并且这两个基因以相反的方向转录。此外，我们使用引物延伸，缺失分析，和lrp-lacZ转录融合描绘的启动子和调控区的lrp操纵子。lrp启动子位于lrp基因翻译起始密码子上游267个核苷酸处。与野生型菌株相比，Lrp操纵子的表达在缺乏Lrp的菌株中增加约3倍，在过量产生Lrp的菌株中降低约10倍。如从DNA迁移率变化和DNA酶I足迹分析所观察到的，Lrp结合到相对于lrp转录起始点的-80至-32区域内的一个或多个位点。突变分析表明，该相同的区域至少部分地需要在体内抑制lrp表达。这些结果表明，Lrp的自体调节涉及Lrp直接作用于引起Lrp转录的抑制。
Lrp (leucine-responsive regulatory protein) is a major Escherichia coli regulatory protein which regulates expression of a number of operons, some negatively and some positively. This work relates to a characterization of lrp, the gene encoding Lrp. Nucleotide sequencing established that the coding regions of lrp and trxB (encoding thioredoxin reductase) are separated by 543 bp and that the two genes are transcribed in opposite directions. In addition, we used primer extension, deletion analyses, and lrp-lacZ transcriptional fusions to delineate the promoter and regulatory region of the lrp operon. The lrp promoter is located 267 nucleotides upstream of the translational start codon of the lrp gene. In comparison with a wild-type strain, expression of the lrp operon was increased about 3-fold in a strain lacking Lrp and decreased about 10-fold in a strain overproducing Lrp. As observed from DNA mobility shift and DNase I footprinting analyses, Lrp binds to one or more sites within the region -80 to -32 relative to the start point of lrp transcription. A mutational analysis indicated that this same region is at least partly required for repression of lrp expression in vivo. These results demonstrate that autogenous regulation of lrp involves Lrp acting directly to cause repression of lrp transcription.