Original Paper

Archives of Microbiology

, Volume 192, Issue 8, pp 673-683

Open Access This content is freely available online to anyone, anywhere at any time.

Influence of the Escherichia coli oxyR gene function on λ prophage maintenance

  • Monika GlinkowskaAffiliated withDepartment of Molecular Biology, University of Gdańsk
  • , Joanna M. ŁośAffiliated withDepartment of Molecular Biology, University of Gdańsk
  • , Anna SzambowskaAffiliated withLaboratory of Molecular Biology (affiliated with the University of Gdańsk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences
  • , Agata CzyżAffiliated withLaboratory of Molecular Biology (affiliated with the University of Gdańsk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences
  • , Joanna CałkiewiczAffiliated withInstitute of Oceanology, Polish Academy of Sciences
  • , Anna Herman-AntosiewiczAffiliated withDepartment of Molecular Biology, University of Gdańsk
  • , Borys WróbelAffiliated withInstitute of Oceanology, Polish Academy of SciencesLaboratory of Bioinformatics, Adam Mickiewicz University
  • , Grzegorz WęgrzynAffiliated withDepartment of Molecular Biology, University of Gdańsk
  • , Alicja WęgrzynAffiliated withLaboratory of Molecular Biology (affiliated with the University of Gdańsk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences
    • , Marcin ŁośAffiliated withDepartment of Molecular Biology, University of GdańskInstitute of Physical Chemistry, Polish Academy of Sciences Email author 

Abstract

In Escherichia coli hosts, hydrogen peroxide is one of the factors that may cause induction of λ prophage. Here, we demonstrate that H2O2-mediated λ prophage induction is significantly enhanced in the oxyR mutant host. The mRNA levels for cI gene expression were increased in a λ lysogen in the presence of H2O2. On the other hand, stimulation of the p M promoter by cI857 overproduced from a multicopy plasmid was decreased in the ΔoxyR mutant in the presence of H2O2 but not under normal growth conditions. The purified OxyR protein did bind specifically to the p M promoter region. This binding impaired efficiency of interaction of the cI protein with the OR3 site, while stimulating such a binding to OR2 and OR1 sites, in the regulatory region of the p M promoter. We propose that changes in cI gene expression, perhaps in combination with moderately induced SOS response, may be responsible for enhanced λ prophage induction by hydrogen peroxide in the oxyR mutant. Therefore, OxyR seems to be a factor stimulating λ prophage maintenance under conditions of oxidative stress. This proposal is discussed in the light of efficiency of induction of lambdoid prophages bearing genes coding for Shiga toxins.

Keywords

λ Prophage induction Shiga toxin-encoding lambdoid phages OxyR protein Hydrogen peroxide