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

• Published in: Archives of microbiology 2010-08, Vol.192 (8), p.673-683
• Main Authors: Glinkowska, Monika, Łoś, Joanna M, Szambowska, Anna, Czyż, Agata, Całkiewicz, Joanna, Herman-Antosiewicz, Anna, Wróbel, Borys, Węgrzyn, Grzegorz, Węgrzyn, Alicja, Łoś, Marcin
• Format: Article
• Language: English
• Subjects: Bacteriology; Bacteriophage lambda - drug effects; Bacteriophage lambda - physiology; Base Sequence; Binding Sites; Biochemistry; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Cell Biology; Ecology; Escherichia coli - genetics; Escherichia coli - metabolism; Escherichia coli - virology; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Viral; hydrogen peroxide; Hydrogen Peroxide - pharmacology; Life Sciences; Microbial Ecology; Microbiology; Miscellaneous; Molecular Sequence Data; Original Paper; Oxidative Stress; OxyR protein; Promoter Regions, Genetic; Prophages - drug effects; Prophages - physiology; Repressor Proteins - genetics; Repressor Proteins - metabolism; Shiga toxin-encoding lambdoid phages; SOS Response (Genetics); Virology; Virus Activation; λ Prophage induction
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/s00203-010-0596-2

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.