A genetic selection reveals functional metastable structures embedded in a toxin-encoding mRNA
- INSERM U1212, CNRS UMR5320, University of Bordeaux, France
Abstract
Post-transcriptional regulation plays important roles to finely tune gene expression in bacteria. In particular, regulation of type I toxin-antitoxin (TA) systems is achieved through sophisticated mechanisms involving toxin mRNA folding. Here, we set up a genetic approach to decipher the molecular underpinnings behind the regulation of a type I TA in Helicobacter pylori. We used the lethality induced by chromosomal inactivation of the antitoxin to select mutations that suppress toxicity. We found that single point mutations are sufficient to allow cell survival. Mutations located either in the 5' untranslated region or within the open reading frame of the toxin hamper its translation by stabilizing stem-loop structures that sequester the Shine-Dalgarno sequence. We propose that these short hairpins correspond to metastable structures that are transiently formed during transcription to avoid premature toxin expression. This work uncovers the co-transcriptional inhibition of translation as an additional layer of TA regulation in bacteria.
Data availability
Sequencing data have been deposited in GEO under accession code GSE121423
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High-throughput suppressor selection of a type I toxin-antitoxin system in Helicobacter pyloriNCBI Gene Expression Omnibus, GSE121423.
Article and author information
Author details
Funding
Agence Nationale de la Recherche (ANR-12-BSV5-0025-Bactox1)
- Sandrine Chabas
- Isabelle Iost
- Fabien Darfeuille
H2020 Marie Skłodowska-Curie Actions (642738)
- Sara Masachis
- Fabien Darfeuille
Agence Nationale de la Recherche (ANR-12-BSV6-007- asSUPYCO)
- Sandrine Chabas
- Isabelle Iost
- Fabien Darfeuille
Institut National de la Santé et de la Recherche Médicale (U1212)
- Sara Masachis
- Nicolas J Tourasse
- Marion Faucher
- Sandrine Chabas
- Isabelle Iost
- Fabien Darfeuille
Centre National de la Recherche Scientifique (UMR 5320)
- Isabelle Iost
- Fabien Darfeuille
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2019, Masachis et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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A genetic selection reveals functional metastable structures embedded in a toxin-encoding mRNA
eLife 8:e47549.
https://doi.org/10.7554/eLife.47549
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