Dorman C J, Ni Bhriain N, Higgins C F
Department of Biochemistry, University of Dundee, UK.
Nature. 1990 Apr 19;344(6268):789-92. doi: 10.1038/344789a0.
Bacterial pathogens undergo profound physiological changes when they infect their hosts, requiring coordinated regulation of gene expression in response to the stresses encountered during infection. A number of environmental stresses (such as osmotic shock and anaerobiosis) have been shown to induce changes in DNA supercoiling that can directly affect the transcription of a specific subset of bacterial genes, at least some of which (the outer-membrane porins and type 1 fimbriae) play a part in bacterial virulence. Here, we demonstrate that the virR gene of S. flexneri, implicated in the temperature regulation of plasmid-encoded virulence genes, is equivalent to the osmZ gene of Escherichia coli, which has previously been shown to mediate its regulatory effects through changes in DNA supercoiling. Our results imply that environmentally induced changes in DNA supercoiling are important in the coordinated control of virulence gene expression in S. flexneri and have general implications for the control of bacterial virulence.
当细菌病原体感染宿主时，它们会经历深刻的生理变化，这需要对基因表达进行协调调控，以应对感染过程中遇到的压力。许多环境压力（如渗透压休克和厌氧状态）已被证明会诱导DNA超螺旋发生变化，这可能直接影响细菌特定基因子集的转录，其中至少一些基因（外膜孔蛋白和1型菌毛）在细菌毒力中发挥作用。在此，我们证明，弗氏志贺氏菌中与质粒编码的毒力基因温度调节有关的virR基因，等同于大肠杆菌的osmZ基因，此前已表明该基因通过DNA超螺旋的变化介导其调节作用。我们的结果表明，环境诱导的DNA超螺旋变化在弗氏志贺氏菌毒力基因表达的协调控制中很重要，并且对细菌毒力的控制具有普遍意义。
