Multiple controls affect arsenite oxidase gene expression in Herminiimonas arsenicoxydans.
Multiple controls affect arsenite oxidase gene expression in Herminiimonas arsenicoxydans.
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DOI：
10.1186/1471-2180-10-53
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发表时间：
2010-02-18
期刊：
影响因子：
4.2
通讯作者：
Bertin PN
中科院分区：
文献类型：
--
作者：
Koechler S;Cleiss-Arnold J;Proux C;Sismeiro O;Dillies MA;Goulhen-Chollet F;Hommais F;Lièvremont D;Arsène-Ploetze F;Coppée JY;Bertin PN
砷的形态和毒性都受到细菌转化的影响，即氧化、还原或甲基化。这些转化对环境污染，特别是对饮用水的砷污染有重大影响。氧化砷单胞菌已从砷污染的环境中分离出来，并已发展出各种处理砷的机制，包括将As（III）氧化为As（V）作为解毒机制.在本研究中，差异转录组分析被用来确定基因，包括亚砷酸氧化酶编码基因，参与H。氧化砷转化为As（III）。为了深入了解这种酶活性的分子机制，进行了Tn 5转座子诱变。转座子插入导致亚砷酸氧化酶活性的缺乏破坏aoxR和aoxS基因，表明aox操纵子转录受AoxRS双组分系统的调节。值得注意的是，在编码RNA聚合酶的替代N σ因子（σ54）的rpoN和编码Hsp 70共伴侣的dnaJ中也鉴定了转座子插入。用抗-AoxB抗体和定量RT-PCR实验的Western印迹使我们能够证明，rpoN和dnaJ基因产物参与控制亚砷酸氧化酶基因的表达。最后，利用cDNA末端快速扩增（RACE）确定了aoxAB操纵子的转录起始位点，并在aoxAB编码序列上游鉴定了一个推定的-12/-24 σ54依赖性启动子基序。这些结果揭示了控制H中亚砷酸盐氧化酶表达的新型分子调节过程的存在。氧化砷这些数据总结在一个模型中，功能集成亚砷酸盐氧化的适应性反应，在这种微生物中的As（III）。
Both the speciation and toxicity of arsenic are affected by bacterial transformations, i.e. oxidation, reduction or methylation. These transformations have a major impact on environmental contamination and more particularly on arsenic contamination of drinking water. Herminiimonas arsenicoxydans has been isolated from an arsenic- contaminated environment and has developed various mechanisms for coping with arsenic, including the oxidation of As(III) to As(V) as a detoxification mechanism. In the present study, a differential transcriptome analysis was used to identify genes, including arsenite oxidase encoding genes, involved in the response of H. arsenicoxydans to As(III). To get insight into the molecular mechanisms of this enzyme activity, a Tn5 transposon mutagenesis was performed. Transposon insertions resulting in a lack of arsenite oxidase activity disrupted aoxR and aoxS genes, showing that the aox operon transcription is regulated by the AoxRS two-component system. Remarkably, transposon insertions were also identified in rpoN coding for the alternative N sigma factor (σ54) of RNA polymerase and in dnaJ coding for the Hsp70 co-chaperone. Western blotting with anti-AoxB antibodies and quantitative RT-PCR experiments allowed us to demonstrate that the rpoN and dnaJ gene products are involved in the control of arsenite oxidase gene expression. Finally, the transcriptional start site of the aoxAB operon was determined using rapid amplification of cDNA ends (RACE) and a putative -12/-24 σ54-dependent promoter motif was identified upstream of aoxAB coding sequences. These results reveal the existence of novel molecular regulatory processes governing arsenite oxidase expression in H. arsenicoxydans. These data are summarized in a model that functionally integrates arsenite oxidation in the adaptive response to As(III) in this microorganism.
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影响因子：
5.1
作者：
Cases, I;Ussery, DW;de Lorenzo, V
通讯作者：
de Lorenzo, V
影响因子：
4.4
作者：
Clingenpeel, Scott R.;D'Imperio, Seth;McDermott, Timothy R.
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McDermott, Timothy R.
影响因子：
3.2
作者：
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Lett, MC
影响因子：
10.4
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影响因子：
3.6
作者：
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