Publication:
Overexpression of the recA gene decreases oral but not intraperitoneal fitness of Salmonella enterica

Date

2010

Authors

Medina-Ruiz, Laura
Campoy Sánchez, Susana
Cardenas, Paula
Alonso, Juan Carlos
Barbé, Jordi

Director

Publisher

American Society for Microbiology
Acceso abierto / Sarbide irekia
Artículo / Artikulua
Versión publicada / Argitaratu den bertsioa

Project identifier

Abstract

Transcription of the Salmonella enterica recA gene is negatively controlled by the LexA protein, the repressor of the SOS response. The introduction of a mutation (recAo6869) in the LexA binding site, in the promoter region of the S. enterica ATCC 14028 recA gene, allowed the analysis of the effect that RecA protein overproduction has on the fitness of this virulent strain. The fitness of orally but not intraperitoneally inoculated recAo6869 cells decreased dramatically. However, the SOS response of this mutant was induced normally, and there was no increase in the sensitivity of the strain toward DNA-damaging agents, bile salts, or alterations in pH. Nevertheless, S. enterica recAo6869 cells were unable to swarm and their capacity to cross the intestinal epithelium was significantly reduced. The swarming deficiency in recAo6869 cells is independent of the flagellar phase. Moreover, swimming activity of the recAo6869 strain was not diminished with respect to the wild type, indicating that the flagellar synthesis is not affected by RecA protein overproduction. In contrast, swarming was recovered in a recAo6869 derivative that overproduced CheW, a protein known to be essential for this function. These data demonstrate that an equilibrium between the intracellular concentrations of RecA and CheW is necessary for swarming in S. enterica. Our results are the first to point out that the SOS response plays a critical role in the prevention of DNA damage by abolishing bacterial swarming in the presence of a genotoxic compound.

Description

Keywords

Salmonella enterica, Rec A

Department

IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua

Faculty/School

Degree

Doctorate program

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