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Auto-regulation of DNA degrading bacteriocins: molecular and ecological aspects

Lusine Ghazaryan1, M Ines M Soares, Osnat Gillor

  • 1Zuckerberg Institute for Water Research, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer Campus, Midreshet Ben Gurion, 84990, Beer-Sheva, Israel.

Antonie Van Leeuwenhoek
|February 22, 2014
PubMed

Insights

Colicin-producing bacteria can induce their own lethal toxin production by triggering their DNA repair system. This self-poisoning mechanism, a population-level trait, enhances colicin expression under stress.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Colicins are protein antibiotics from E. coli that kill competing bacteria via various mechanisms.
  • Colicin gene expression is tightly regulated by the SOS response, a DNA damage-induced system.
  • Sophisticated repression and expression systems govern colicin production due to their lethal nature.

Purpose of the Study:

  • To investigate the novel induction mechanism of colicin expression in DNA-degrading colicins.
  • To determine if colicinogenic strains can self-induce their own production.
  • To understand the population dynamics and costs associated with this self-regulation.

Main Methods:

  • Analysis of colicin gene expression in 13 different colicins.
  • Induction of the SOS response system using various stress conditions.
  • Comparative studies on individual cell versus population-mediated expression.

Main Results:

  • A novel self-induction mechanism was identified in strains producing DNA-degrading colicins.
  • Three of the four known DNase colicins (E2, E7, E8, E9) were found to self-induce production.
  • This self-regulation incurs significant costs under suboptimal growth and is a population-level trait.

Conclusions:

  • Colicinogenic strains employ a unique self-poisoning strategy to induce DNA-degrading colicin expression via the SOS system.
  • This population-mediated trait highlights a trade-off between self-regulation and growth efficiency.
  • The findings offer insights into colicin regulation, molecular mechanisms, and evolutionary strategies.

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