A genetic selection reveals functional metastable structures embedded in a toxin-encoding mRNA

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

The following data sets were generated

Article and author information

Author details

  1. Sara Masachis

    ARNA laboratory, INSERM U1212, CNRS UMR5320, University of Bordeaux, Bordeaux, France
    Competing interests
    The authors declare that no competing interests exist.
  2. Nicolas J Tourasse

    ARNA laboratory, INSERM U1212, CNRS UMR5320, University of Bordeaux, Bordeaux, France
    Competing interests
    The authors declare that no competing interests exist.
  3. Claire Lays

    ARNA laboratory, INSERM U1212, CNRS UMR5320, University of Bordeaux, Bordeaux, France
    Competing interests
    The authors declare that no competing interests exist.
  4. Marion Faucher

    ARNA laboratory, INSERM U1212, CNRS UMR5320, University of Bordeaux, Bordeaux, France
    Competing interests
    The authors declare that no competing interests exist.
  5. Sandrine Chabas

    ARNA laboratory, INSERM U1212, CNRS UMR5320, University of Bordeaux, Bordeaux, France
    Competing interests
    The authors declare that no competing interests exist.
  6. Isabelle Iost

    ARNA laboratory, INSERM U1212, CNRS UMR5320, University of Bordeaux, Bordeaux, France
    Competing interests
    The authors declare that no competing interests exist.
  7. Fabien Darfeuille

    ARNA laboratory, INSERM U1212, CNRS UMR5320, University of Bordeaux, Bordeaux, France
    For correspondence
    fabien.darfeuille@inserm.fr
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-1167-6113

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.

Reviewing Editor

  1. Gisela Storz, National Institute of Child Health and Human Development, United States

Version history

  1. Received: April 9, 2019
  2. Accepted: August 14, 2019
  3. Accepted Manuscript published: August 14, 2019 (version 1)
  4. Version of Record published: September 9, 2019 (version 2)

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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  1. Sara Masachis
  2. Nicolas J Tourasse
  3. Claire Lays
  4. Marion Faucher
  5. Sandrine Chabas
  6. Isabelle Iost
  7. Fabien Darfeuille
(2019)
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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