The Staphylococcus aureus Thiol/Oxidative Stress Global Regulator Spx Controls trfA, a Gene Implicated in Cell Wall Antibiotic Resistance
The Staphylococcus aureus Thiol/Oxidative Stress Global Regulator Spx Controls trfA, a Gene Implicated in Cell Wall Antibiotic Resistance
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DOI：
10.1128/aac.00220-13
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发表时间：
2013-07-01
影响因子：
4.9
通讯作者：
Renzoni, Adriana
中科院分区：
文献类型：
--
作者：
Jousselin, Ambre;Kelley, William L.;Renzoni, Adriana
S.金黄色葡萄球菌通过改变由各种环境信号传感器介导的基因表达来对抗细胞壁抗生素应激。在这项研究中，我们研究了trfA的转录调控，枯草芽孢杆菌的mecA相关的基因编码的衔接蛋白牵连在多个角色，特别是，蛋白水解和遗传能力。尽管与B有很强的序列相似性。subtilis mecA的功能;金黄色葡萄球菌trfA仍然在很大程度上未被探索;然而，其缺失导致糖肽中间体S中对苯唑西林和糖肽抗生素的抗性几乎完全丧失。金黄色葡萄球菌（GISA）的甲氧西林敏感或甲氧西林抗性S.金黄色葡萄球菌（MRSA）临床或实验室分离株。北方印迹分析和5'端cDNA末端快速扩增（RACE）作图表明，trfA基因由3个启动子单顺反子表达。细胞壁活性抗生素暴露导致增加的trfA转录和增强的稳态TrfA水平。trfA启动子调控不依赖于细胞壁应力哨兵VraSR和其他感觉应力系统，如GraRS，WalkRK，Stk 1/Stp 1和SigB。值得注意的是，我们发现，全球氧化应激调节Spx控制trfA转录。这一发现也证实了使用增强的Spx水平的菌株，由缺陷yjbH，编码Spx相互作用蛋白的Spx蛋白水解降解。一组临床GISA菌株显示，与相应的敏感亲本菌株相比，trfA的稳态上调显著，进一步支持了trfA在抗生素耐药性中的作用。这些数据为细胞壁抗生素应激和氧化应激传感器介导的诱发反应之间的联系提供了强有力的证据。
S. aureus combats cell wall antibiotic stress by altered gene expression mediated by various environmental signal sensors. In this study, we examined the transcriptional regulation of trfA, a gene related to mecA of Bacillus subtilis encoding an adaptor protein implicated in multiple roles, notably, proteolysis and genetic competence. Despite strong sequence similarity to B. subtilis mecA, the function of S. aureus trfA remains largely unexplored; however, its deletion leads to almost complete loss of resistance to oxacillin and glycopeptide antibiotics in glycopeptide-intermediate S. aureus (GISA) derivatives of methicillin-susceptible or methicillin-resistant S. aureus (MRSA) clinical or laboratory isolates. Northern blot analysis and 5' rapid amplification of cDNA ends (RACE) mapping revealed that trfA was expressed monocistronically by three promoters. Cell wall-active antibiotic exposure led to both increased trfA transcription and enhanced steady-state TrfA levels. trfA promoter regulation was not dependent upon the cell wall stress sentinel VraSR and other sensory stress systems, such as GraRS, WalkRK, Stk1/Stp1, and SigB. Notably, we discovered that the global oxidative-stress regulator Spx controlled trfA transcription. This finding was also confirmed using a strain with enhanced Spx levels resulting from a defect in yjbH, encoding a Spx-interacting protein governing Spx proteolytic degradation. A cohort of clinical GISA strains revealed significant steady-state upregulation of trfA compared to corresponding susceptible parental strains, further supporting a role for trfA in antibiotic resistance. These data provide strong evidence for a link between cell wall antibiotic stress and evoked responses mediated by an oxidative-stress sensor.