An ideR mutant of Mycobacterium smegmatis has derepressed siderophore production and an altered oxidative-stress response
An ideR mutant of Mycobacterium smegmatis has derepressed siderophore production and an altered oxidative-stress response
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DOI：
10.1046/j.1365-2958.1996.1461511.x
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发表时间：
1996-11-01
影响因子：
3.6
通讯作者：
Smith, I
中科院分区：
文献类型：
--
作者：
Dussurget, O;Rodriguez, M;Smith, I
分枝杆菌的IdeR蛋白是白喉毒素抑制因子DtxR的同源物。我们之前已经证明，结核分枝杆菌内毒素，像DtxR一样，在体内抑制白喉棒状杆菌铁调控启动子的转录，并在体外以金属依赖的方式与白喉支链杆菌操作子结合。我们在这里表明，通过等位基因替换构建的耻垢分枝杆菌的ideR突变体在铁存在下抑制铁载体生物合成的能力存在缺陷。他们对过氧化氢也更敏感，过氧化氢酶/过氧化物酶（KatG）和锰超氧化物歧化酶（Mn-SOD）水平降低。这表明IdeR是铁载体产生的负调节因子，是对超氧化物和过氧化氢胁迫的反应所必需的。我们认为IdeR是大肠杆菌Fur蛋白的分枝杆菌对应物，即它是一种多效调节剂，将铁代谢与氧化应激反应结合起来。
The mycobacterial IdeR protein is a homologue of the diphtheria-toxin repressor DtxR. We have previously demonstrated that Mycobacterium tuberculosis IdeR, like DtxR, represses transcription of Corynebacterium diphtheriae iron-regulated promoters in vivo and binds to C. diphtheriae operators in a metal-dependent manner in vitro. We show here that ideR mutants of M. smegmatis, constructed by allelic replacement, were defective in their ability to repress siderophore biosynthesis in the presence of iron. They were also more sensitive to hydrogen peroxide and had decreased levels of catalase/peroxidase (KatG) and manganese superoxide dismutase (Mn-SOD). This indicates that IdeR is a negative regulator of siderophore production and is required for the response to superoxide- and hydrogen peroxide stress. We propose that IdeR is the mycobacterial counterpart of the Escherichia coli Fur protein, i.e. it is a pleiotropic regulator that couples iron metabolism to the oxidative-stress response.