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Toxins 2016, 8(4), 113;

Identification and Characterization of the HicAB Toxin-Antitoxin System in the Opportunistic Pathogen Pseudomonas aeruginosa

Department of Microbiology, Third Military Medical University, Chongqing 400038, China
Authors to whom correspondence should be addressed.
Academic Editor: Anton Meinhart
Received: 21 March 2016 / Revised: 6 April 2016 / Accepted: 8 April 2016 / Published: 19 April 2016
(This article belongs to the Special Issue Toxin-Antitoxin System in Bacteria)
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Toxin-antitoxin (TA) systems are small genetic modules that are widely distributed in the genomes of bacteria and archaea and have been proposed to fulfill numerous functions. Here, we describe the identification and characterization of a type II TA system, comprising the hicAB locus in the human opportunistic pathogen Pseudomonas aeruginosa. The hicAB locus consists of genes hicA and hicB encoding a toxin and its cognate antitoxin, respectively. BLAST analysis revealed that hicAB is prevalent in approximately 36% of P. aeruginosa strains and locates in the same genomic region. RT-PCR demonstrated that hicAB forms a bicistronic operon that is cotranscribed under normal growth conditions. Overproduction of HicA inhibited the growth of Escherichia coli, and this effect could be counteracted by co-expression of HicB. The Escherichia coli kill/rescue assay showed that the effect of HicA is bacteriostatic, rather than bactericidal. Deletion of hicAB had no effect on the biofilm formation and virulence of P. aeruginosa in a mice infection model. Collectively, this study presents the first characterization of the HicAB system in the opportunistic pathogen P. aeruginosa. View Full-Text
Keywords: toxin-antitoxin system; HicAB; Pseudomonas aeruginosa; biofilm formation; virulence toxin-antitoxin system; HicAB; Pseudomonas aeruginosa; biofilm formation; virulence

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Li, G.; Shen, M.; Lu, S.; Le, S.; Tan, Y.; Wang, J.; Zhao, X.; Shen, W.; Guo, K.; Yang, Y.; Zhu, H.; Rao, X.; Hu, F.; Li, M. Identification and Characterization of the HicAB Toxin-Antitoxin System in the Opportunistic Pathogen Pseudomonas aeruginosa. Toxins 2016, 8, 113.

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