title: Heat-shock-induced refolding entails rapid degradation of bsrG toxin mRNA by RNases Y and J1.
abstract: Gene regulation accomplished by alternative folding of an mRNA is a widely used mechanism. Classical examples are the various transcriptional attenuation mechanisms that employ, for example, leader peptide translation, or binding of a modified protein, an uncharged tRNA or an antisense RNA to the 5' untranslated region of an mRNA. With the discovery of transcriptional and translational riboswitches, it became clear that small metabolites or even metal ions can also alter RNA secondary structures and, hence, gene expression. In addition, biophysical factors like temperature can affect RNA folding, as exemplified by RNA thermometers. We have investigated in detail the type I toxin-antitoxin system bsrG/SR4 from Bacillus subtilis. The antitoxin SR4 is a cis-encoded regulatory RNA that neutralizes BsrG toxin action. SR4 prevents toxin expression by promoting degradation of the toxin mRNA and inhibiting its translation. In addition, upon temperature shock the amount of toxin mRNA decreases significantly. Here, we demonstrate that heat shock induces a refolding in the central region of the toxin mRNA that makes it more accessible to degradation by RNases Y and J1. Furthermore, we show that BsrG might play a role at the onset of stationary phase, when the antitoxin SR4 can no longer prevent toxin synthesis.
authors.affiliation: Friedrich-Schiller-Universität Jena, Lehrstuhl für Genetik, AG Bakteriengenetik, Philosophenweg 12, 07743 Jena, Germany.
authors.forename: Natalie
authors.initials: N
authors.lastname: Jahn
authors.affiliation: Friedrich-Schiller-Universität Jena, Lehrstuhl für Genetik, AG Bakteriengenetik, Philosophenweg 12, 07743 Jena, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Brantl
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology* / Q000528:radiation effects*; D015964:Gene Expression Regulation, Bacterial; D006358:Hot Temperature; D059370:RNA Folding / Q000528:radiation effects*; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism*; D013997:Time Factors
chemical_list: D012333:RNA, Messenger; D012260:Ribonucleases