Cross-Regulations between Bacterial Toxin–Antitoxin Systems: Evidence of an Interconnected Regulatory Network?. Issue 10 (October 2020)

• Record Type: Journal Article
• Authors: Riffaud, Camille; Pinel-Marie, Marie-Laure; Felden, Brice
• Is Part Of: Trends in microbiology. Volume 28:Issue 10(2020)
• Page Start: 851
• Page End: 866
• Publication Date: 2020-10
• Subjects: toxin–antitoxin -- cross-regulation -- cross-activation; Microbiology -- Periodicals; Infection -- Periodicals; Virulence (Microbiology) -- Periodicals; Infection -- Periodicals; Microbiology -- Periodicals; Virulence -- Periodicals; Microbiologie -- Périodiques; Infection -- Périodiques; Virulence (Microbiologie) -- Périodiques; Infection; Microbiology; Virulence (Microbiology); 579
• DOI: 10.1016/j.tim.2020.05.016
• Languages: English
• ISSNs: 0966-842X

Abstract

Abstract : Toxin–antitoxin (TA) systems are ubiquitous among bacteria and include stable toxins whose toxicity can be counteracted by RNA or protein antitoxins. They are involved in multiple functions that range from stability maintenance for mobile genetic elements to stress adaptation. Bacterial chromosomes frequently have multiple homologues of TA system loci, and it is unclear why there are so many of them. In this review we focus on cross-regulations between TA systems, which occur between both homologous and nonhomologous systems, from similar or distinct types, whether encoded from plasmids or chromosomes. In addition to being able to modulate RNA expression levels, cross-regulations between these systems can also influence their toxicity. This suggests the idea that they are involved in an interconnected regulatory network. Highlights: TA systems are genetic modules in bacteria that encode both a stable toxic protein and a labile antitoxin which neutralizes the toxin's activity. They are classified into six types depending on the antitoxin's nature and mode of action, with toxins that are always proteins and antitoxins that are either small RNAs or proteins. The coexistence of both homologous and nonhomologous TA systems in bacterial genomes suggests that cross-regulation between them is very likely. Cross-regulations can influence RNA levels or the toxicity of other TA systems. Type II antitoxins are global regulators of gene expression via their DNA-binding domains. TA systems can act individually or within an extended gene network containing cross-regulations between homologous and nonhomologous TA systems among various types.