METALLOREGULATION IN BACILLUS-SUBTILIS - ISOLATION AND CHARACTERIZATION OF 2 GENES DIFFERENTIALLY REPRESSED BY METAL-IONS
METALLOREGULATION IN BACILLUS-SUBTILIS - ISOLATION AND CHARACTERIZATION OF 2 GENES DIFFERENTIALLY REPRESSED BY METAL-IONS
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DOI：
10.1128/jb.175.17.5428-5437.1993
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发表时间：
1993-09-01
影响因子：
3.2
通讯作者：
HELMANN, JD
中科院分区：
文献类型：
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作者：
CHEN, L;JAMES, LP;HELMANN, JD
我们利用转座子Tn 917-lacZ从枯草芽孢杆菌中克隆了两个金属调控基因（mrgA和mrgC）。两者都是作为铁抑制基因融合体分离的，但基因抑制的金属特异性和敏感性是不同的。mrgA-lacZ的转录在基本培养基中的细菌生长期结束时被诱导，并且这种诱导被过量的锰、铁、钴或铜阻止。限制金属离子是足够的mrgA-lacZ诱导，因为重悬在培养基中缺乏锰和铁迅速诱导转录。mrgC-lacZ的转录也被铁剥夺诱导，但不被添加的锰或其他金属离子抑制。mrgC-lacZ和2，3-二羟基苯甲酸为基础的铁载体的表达被抑制在平行的铁，在这两种情况下，只有铁的效果抑制。我们克隆并测序了mrgA和mrgC的启动子和调控区。这两个基因之前的预测sigma（A）依赖性启动子元件与重叠序列相似的铁盒共识元件识别的大肠杆菌铁摄取调节蛋白（Fur）。基因mrgC的假定铁盒的突变导致在充满铁的培养基中的部分去阻遏。
We have cloned two metal-regulated genes (mrgA and mrgC) from Bacillus subtilis by using transposon Tn917-lacZ. Both were isolated as iron-repressible gene fusions, but the metal specificity and sensitivity of gene repression are distinct. Transcription of mrgA-lacZ is induced at the end of logarithmic-phase growth in minimal medium, and this induction is prevented by excess manganese, iron, cobalt, or copper. Limitation for metal ions is sufficient for mrgA-lacZ induction, since resuspension in medium lacking both manganese and iron rapidly induces transcription. Transcription of mrgC-lacZ is also induced by iron deprivation but is not repressed by added manganese or other metal ions. Expression of mrgC-lacZ and a 2,3-dihydroxybenzoic acid-based siderophore is repressed in parallel by iron, and in both cases, only iron effects repression. We have cloned and sequenced the promoter and regulatory regions of both mrgA and mrgC. Both genes are preceded by a predicted sigma(A)-dependent promoter element with overlapping sequences similar to the iron box consensus element for recognition by the Escherichia coli ferric uptake regulator protein (Fur). Mutation of the putative iron box for gene mrgC leads to partial derepression in iron-replete medium.