Toxin–antitoxin (TA) systems are small genetic modules usually consisting of two elements—a toxin and an antitoxin. The abundance of TA systems among various bacterial strains may indicate an important evolutionary role. Pseudomonas aeruginosa, which can be found in a variety of niches in nature, is an opportunistic pathogen for various hosts. While P. aeruginosa strains are very versatile and diverse, only a few TA systems were characterized in this species. Here, we describe a newly characterized TA system in P. aeruginosa that is encoded within the filamentous Pf4 prophage. This system, named PfiT/PfiA, is a homologue of the ParE/YefM TA system. It is a type II TA system, in which the antitoxin is a protein that binds the toxic protein and eliminates the toxic effect. PfiT/PfiA carries several typical type II characteristics. Specifically, it constitutes two small genes expressed in a single operon, PfiT inhibits growth and PfiA eliminates this effect, PfiA binds PfiT, and PfiT expression results in elongated cells. Finally, we assigned a novel function to this TA system, where an imbalance between PfiT and PfiA, favouring the toxin, resulted in cell elongation and an increase in virion production.

中文翻译：

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铜绿假单胞菌的PfiT / PfiA毒素-抗毒素系统的表征，可影响细胞伸长和噬菌体诱导。

毒素-抗毒素（TA）系统是小型遗传模块，通常由两个元素组成-毒素和抗毒素。各种细菌菌株中TA系统的丰富性可能表明了重要的进化作用。铜绿假单胞菌（Pseudomonas aeruginosa）可以在自然界的各种生态位中发现，是各种宿主的机会病原体。虽然P。铜绿假单胞菌菌株非常通用且种类繁多，在该物种中仅鉴定了少数TA系统。在这里，我们描述了P中一个新特性的TA系统。铜绿编码在丝状Pf4噬菌体中。该系统名为PfiT / PfiA，是ParE / YefM TA系统的同系物。它是II型TA系统，其中抗毒素是一种结合有毒蛋白质并消除毒性作用的蛋白质。PfiT / PfiA具有几种典型的II型特征。具体来说，它构成在单个操纵子中表达的两个小基因，PfiT抑制生长，PfiA消除这种作用，PfiA结合PfiT，PfiT表达导致伸长的细胞。最后，我们为该TA系统分配了一种新功能，其中PfiT和PfiA之间的不平衡（有利于毒素）导致细胞伸长和病毒体产量增加。