title: sRNAs in bacterial type I and type III toxin-antitoxin systems.
abstract: Toxin-antitoxin (TA) loci consist of two genes: a stable toxin whose overexpression kills the cell or causes growth stasis and an unstable antitoxin that neutralizes the toxin action. Currently, five TA systems are known. Here, we review type I and type III systems in which the antitoxins are regulatory RNAs. Type I antitoxins act by a base-pairing mechanism on toxin mRNAs. By contrast, type III antitoxins are RNA pseudoknots that bind their cognate toxins directly in an RNA-protein interaction. Whereas for a number of plasmid-encoded systems detailed information on structural requirements, kinetics of interaction with their targets and regulatory mechanisms employed by the antitoxin RNAs is available, the investigation of chromosomal systems is still in its infancy. Here, we summarize our current knowledge on that topic. Furthermore, we compare factors and conditions that induce antitoxins or toxins and different mechanisms of toxin action. Finally, we discuss biological roles for chromosome-encoded TA systems.
authors: AG Bakteriengenetik, Lehrstuhl für Genetik, Friedrich-Schiller-Universität Jena, Philosophenweg 12, D-07743 Jena, Germany Sabine.Brantl@rz.uni-jena.de.
authors: Sabine
authors: S
authors: Brantl
authors: AG Bakteriengenetik, Lehrstuhl für Genetik, Friedrich-Schiller-Universität Jena, Philosophenweg 12, D-07743 Jena, Germany.
authors: Natalie
authors: N
authors: Jahn
mesh_terms: D000992:Antitoxins / Q000235:genetics*; D001419:Bacteria / Q000235:genetics*; D001427:Bacterial Toxins / Q000235:genetics*; D002876:Chromosomes, Bacterial / Q000235:genetics; D012329:RNA, Bacterial / Q000378:metabolism*; D058727:RNA, Small Untranslated / Q000235:genetics* / Q000378:metabolism*
chemical_list: D000992:Antitoxins; D001427:Bacterial Toxins; D012329:RNA, Bacterial; D058727:RNA, Small Untranslated
keywords: RNA antitoxin; antisense RNA; small regulatory RNA; target RNA interaction; toxic peptide; toxin–antitoxin system; type I and type III TA systems