Solovieva Irina M, Entian Karl-Dieter
Molecular and Radiation Biophysics Division, St. Petersburg Nuclear Physics Institute of the Russian Academy of Sciences.
FEMS Microbiol Lett. 2004 Jul 1;236(1):115-22. doi: 10.1016/j.femsle.2004.05.031.
The copZ gene of Bacillus subtilis encodes a copper chaperon CopZ that donates copper to the copper transporter CopA. Both genes copZ and copA are clustered to an operon and its promoter is regulated by Cu ions and CueR, a Mer-like transcriptional activator. Here we show that cadmium ions activate copZA expression as strong as copper ions. Northern hybridization analysis showed that copper and cadmium both induce the synthesis of a 2.7 kb copZA transcript and a 250 bp copZ transcript. A copA deletion mutant was sensitive to copper, whereas a copZ deletion resulted in an increased sensitivity to cadmium and copper. Transcription of the cadmium resistance gene cadA, which is adjacent to the copZA cluster, is extremely reduced in a copZ deletion strain. Transformation of copZ in trans restores wild type resistance to cadmium and copper in a copZ deletion strain. This excludes any polar effect and proves that the copZ encoded protein is important for copper and cadmium resistance.
枯草芽孢杆菌的copZ基因编码一种铜伴侣蛋白CopZ，它将铜传递给铜转运蛋白CopA。copZ和copA这两个基因聚集在一个操纵子中，其启动子受铜离子和CueR（一种Mer样转录激活因子）调控。在此我们表明，镉离子激活copZA表达的程度与铜离子一样强。Northern杂交分析表明，铜和镉均诱导合成一个2.7 kb的copZA转录本和一个250 bp的copZ转录本。copA缺失突变体对铜敏感，而copZ缺失导致对镉和铜的敏感性增加。与copZA簇相邻的镉抗性基因cadA在copZ缺失菌株中的转录极度减少。将copZ进行反式转化可恢复copZ缺失菌株对镉和铜的野生型抗性。这排除了任何极性效应，并证明copZ编码的蛋白对铜和镉抗性很重要。
