Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
Nat Commun. 2013;4:2012. doi: 10.1038/ncomms3012.
Toxin-antitoxin systems were shown to be involved in plasmid maintenance when they were initially discovered, but other roles have been demonstrated since. Here we identify and characterize a novel toxin-antitoxin system (pemIKSa) located on Staphylococcus aureus plasmid pCH91. The toxin (PemKSa) is a sequence-specific endoribonuclease recognizing the tetrad sequence U↓AUU, and the antitoxin (PemISa) inhibits toxin activity by physical interaction. Although the toxin-antitoxin system is responsible for stable plasmid maintenance our data suggest the participation of pemIKSa in global regulation of staphylococcal virulence by alteration of the translation of large pools of genes. We propose a common mechanism of reversible activation of toxin-antitoxin systems based on antitoxin transcript resistance to toxin cleavage. Elucidation of this mechanism is particularly interesting because reversible activation is a prerequisite for the proposed general regulatory role of toxin-antitoxin systems.
毒素-抗毒素系统最初被发现时被认为与质粒维持有关，但此后已经证明了它们还有其他作用。在这里，我们鉴定并描述了一种位于金黄色葡萄球菌质粒 pCH91 上的新型毒素-抗毒素系统 (pemIKSa)。毒素 (PemKSa) 是一种序列特异性内切核糖核酸酶，识别 tetrad 序列 U↓AUU，而抗毒素 (PemISa) 通过物理相互作用抑制毒素活性。尽管毒素-抗毒素系统负责稳定质粒的维持，但我们的数据表明，pemIKSa 通过改变大量基因的翻译参与了金黄色葡萄球菌毒力的全局调控。我们提出了一种基于抗毒素转录体对毒素切割的抗性的毒素-抗毒素系统可逆激活的通用机制。阐明这种机制特别有趣，因为可逆激活是毒素-抗毒素系统拟议的一般调节作用的前提。
