Hu Yong-Hua, Wang Hua-Lei, Zhang Min, Sun Li
Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, P. R. China.
J Microbiol. 2009 Jun;47(3):277-86. doi: 10.1007/s12275-008-0278-9. Epub 2009 Jun 26.
CopRS/CopABCD is one of the known systems that control copper homeostasis in bacteria. Although CopRS/CopABCD homologues are found to exist in Pseudomonas fluorescens, the potential role of this system in P. fluorescens has not been investigated. In this study a genetic cluster, consisting of copR, S, C, and D but lacking copAB, was identified in a pathogenic P. fluorescens strain (TSS) isolated from diseased fish. The copRSCD cluster was demonstrated to be required for full copper resistance and regulated at the transcription level by Cu. Expression of copCD is regulated directly by the two-component response regulator CopR, which also regulates its own expression. Interruption of the regulated expression of copR affected bacterial growth, biofilm formation, and tissue dissemination and survival. A mutant CopR, which lacks the N-terminal signal receiver domain and is constitutively active, was found to have an attenuating effect on bacterial virulence when expressed in TSS. To our knowledge, this is the first report that suggests a link between CopR and bacterial pathogenicity in P. fluorescens.
CopRS/CopABCD是已知的控制细菌铜稳态的系统之一。尽管发现荧光假单胞菌中存在CopRS/CopABCD同源物，但该系统在荧光假单胞菌中的潜在作用尚未得到研究。在本研究中，从患病鱼类分离出的致病性荧光假单胞菌菌株（TSS）中鉴定出一个由copR、S、C和D组成但缺少copAB的基因簇。结果表明，copRSCD基因簇是完全抗铜所必需的，并且受铜在转录水平上的调控。copCD的表达由双组分响应调节因子CopR直接调控，CopR也调控其自身的表达。copR调控表达的中断影响细菌生长、生物膜形成以及组织扩散和存活。发现一种缺少N端信号接收结构域且组成型激活的突变体CopR在TSS中表达时对细菌毒力有减弱作用。据我们所知，这是第一份表明CopR与荧光假单胞菌细菌致病性之间存在联系的报告。
