Bacterial Proliferation: Keep Dividing and Don't Mind the Gap

PLoS Genet. 2015 Dec 29;11(12):e1005757. doi: 10.1371/journal.pgen.1005757. eCollection 2015 Dec.

Abstract

DNA Damage Tolerance (DDT) mechanisms help dealing with unrepaired DNA lesions that block replication and challenge genome integrity. Previous in vitro studies showed that the bacterial replicase is able to re-prime downstream of a DNA lesion, leaving behind a single-stranded DNA gap. The question remains of what happens to this gap in vivo. Following the insertion of a single lesion in the chromosome of a living cell, we showed that this gap is mostly filled in by Homology Directed Gap Repair in a RecA dependent manner. When cells fail to repair this gap, or when homologous recombination is impaired, cells are still able to divide, leading to the loss of the damaged chromatid, suggesting that bacteria lack a stringent cell division checkpoint mechanism. Hence, at the expense of losing one chromatid, cell survival and proliferation are ensured.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Division*
  • DNA Breaks, Single-Stranded*
  • DNA Damage
  • Escherichia coli / genetics*
  • Escherichia coli / physiology
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Rec A Recombinases / genetics
  • Rec A Recombinases / metabolism
  • Recombinational DNA Repair*

Substances

  • Escherichia coli Proteins
  • Rec A Recombinases

Grants and funding

This work was funded by Équipe Labellisée Ligue Contre le Cancer: http://www.ligue-cancer.net; Agence Nationale de la Recherche (ANR) Grant ForkRepair ANR-11-BSV8-017-01 and GenoBlock ANR-14-CE09-0010-01: http://www.agence-nationale-recherche.fr. LL was supported by a fellowship from the AXA Foundation: http://www.axa-research.org. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.