Overexpression of the hslVU operon suppresses SOS-mediated inhibition of cell division in Escherichia coli
Overexpression of the hslVU operon suppresses SOS-mediated inhibition of cell division in Escherichia coli
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DOI：
10.1016/s0014-5793(97)01024-7
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发表时间：
1997-01-01
期刊：
影响因子：
3.5
通讯作者：
Khattar, Medhat M.
中科院分区：
文献类型：
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作者：
Khattar, Medhat M.
在大肠杆菌离子突变体中分离到一个对SOS诱导剂呋喃妥因产生抗性的多拷贝克隆。在88.5分钟时，从染色体的一个区域发现了含有7-8kbp的HindIII DNA插入的质粒pHL1。PHL1的进一步鉴定表明，呋喃妥因的抗性是由于hslV-hslU操纵子在大肠杆菌中过表达，该操纵子编码一个依赖于ATP的蛋白酶复合体。HslVU的过表达也赋予了离子突变体对紫外线照射的抵抗力。有人认为，当过量生产时，HslV-HslU酶复合体可以降解基本细胞分裂蛋白FtsZ的内源抑制物Sula。HslVU在体内降解Sula的能力表明Lon和HslVU可能共享一系列底物。此外，离子抑制可以作为克隆的HslVU蛋白分解活性的一种简单的遗传测试。
A multicopy clone was isolated which conferred resistance to the SOS inducer nitrofurantoin in an Escherichia coli lon mutant. Plasmid pHL1 was found to contain a 7-8 kbp HindIII DNA insert from a region of the chromosome at 88.5 minutes. Further characterization of pHL1 revealed that resistance to nitrofurantoin was due to the overexpression of the hslV-hslU operon which encodes an ATP-dependent protease complex in E. coli. The overexpression of hslVU also conferred resistance to ultraviolet irradiation in the Ion mutant. It is proposed that when overproduced, the HslV-HslU protease complex can degrade SulA which is an endogenous inhibitor of the essential cell division protein FtsZ. The ability of HslVU to degrade SulA in vivo suggests that Lon and HslVU may share a range of substrates. Furthermore, the suppression of Ion could be used as a simple genetic test of proteolytic activity of cloned HslVU.