Coordinated patterns of cytochrome bd and lactate dehydrogenase expression in Bacillus subtilis
Coordinated patterns of cytochrome bd and lactate dehydrogenase expression in Bacillus subtilis
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DOI：
10.1099/mic.0.28124-0
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发表时间：
2005-10-01
期刊：
影响因子：
2.8
通讯作者：
von Wachenfeldt, C
中科院分区：
文献类型：
--
作者：
Larsson, JT;Rogstam, A;von Wachenfeldt, C
土壤细菌枯草芽孢杆菌中电子和碳流的多种途径根据细胞环境中是否存在氧气而差异表达。本研究表征呼吸氧化酶细胞色素bd和NADH连接的发酵乳酸脱氢酶（LDH）的调节。编码细胞色素bd的cydABCD操纵子的转录受到高度调节，并且仅在低氧可用性下被激活。这种诱导不依赖于编码氧化还原调节剂Fnr的基因或编码ResDE双组分调节系统的基因。发现DNA结合蛋白YdiH是控制cydABCD表达的主要调节剂。cyd启动子的转录被位于核心启动子上游的区域刺激15倍。上游区域可能构成一个未鉴定的转录激活因子的结合位点，该转录激活因子可能影响转录水平，但不影响其时间，这是由YdiH负控制的。这份报告提供的证据表明，YdiH也作为一个抑制剂的LDH基因编码LDH和一个基因，ywcJ，它编码一个假定的甲酸盐-亚硝酸盐转运蛋白。基于YdiH和天蓝色链霉菌的雷克斯蛋白之间的相似性，提出YdiH充当氧化还原传感器，其活性受NAD（+）和NADH游离水平的细胞差异调节。建议将ydiH重命名为雷克斯。
A variety of pathways for electron and carbon flow in the soil bacterium Bacillus subtilis are differentially expressed depending on whether oxygen is present in the cell environment. This study characterizes the regulation of the respiratory oxidase cytochrome bd and the NADH-linked fermentative lactate dehydrogenase, (LDH). Transcription of the cydABCD operon, encoding cytochrome bd, is highly regulated and only becomes activated at low oxygen availability. This induction is not dependent on the gene encoding the redox regulator Fnr or the genes encoding the ResDE two-component regulatory system. The DNA-binding protein YdiH was found to be a principal regulator that controls cydABCD expression. Transcription from the cyd promoter is stimulated 15-fold by a region located upstream of the core promoter. The upstream region may constitute a binding site for an unidentified transcription activator that is likely to influence the level of transcription but not its timing, which is negatively controlled by YdiH. This report provides evidence that YdiH also functions as a repressor of the ldh gene encoding LDH and of a gene, ywcJ, which encodes a putative formate-nitrite transporter. Based on the similarity between YdiH and the Rex protein of Streptomyces coelicolor, it is proposed that YdiH serves as a redox sensor, the activity of which is regulated by cellular differences in the free levels of NAD(+) and NADH. It is suggested that ydiH be renamed as rex.