Abstract
The exo–xis region, present in genomes of lambdoid bacteriophages, contains highly conserved genes of largely unknown functions. In this report, using bacteriophage λ and Shiga toxin-converting bacteriophage ϕ24Β, we demonstrate that the presence of this region on a multicopy plasmid results in impaired lysogenization of Escherichia coli and delayed, while more effective, induction of prophages following stimulation by various agents (mitomycin C, hydrogen peroxide, UV irradiation). Spontaneous induction of λ and ϕ24Β prophages was also more efficient in bacteria carrying additional copies of the corresponding exo–xis region on plasmids. No significant effects of an increased copy number of genes located between exo and xis on both efficiency of adsorption on the host cells and lytic development inside the host cell of these bacteriophages were found. We conclude that genes from the exo–xis region of lambdoid bacteriophages participate in the regulation of lysogenization and prophage maintenance.
Highlights
The family of lambdoid bacteriophages is a group of temperate viruses infecting bacterial cells, which are characterized by a common scheme of genome organization and similar developmental regulation
Pathogenicity of enterohemorrhagic E. coli strains strongly depends on production and release of Shiga toxins (Mauro and Koudelka 2011)
It appears that a biological role for production of Shiga toxins by E. coli may be ascribed to killing unicellular eukaryotic predators, while toxicity to humans was speculated to be a side effect of an attack by human neutrophils which produce hydrogen peroxide, potentially causing Stx prophage induction (Łoset al. 2011, 2012; Mauro and Koudelka 2011)
Summary
The family of lambdoid bacteriophages is a group of temperate viruses infecting bacterial cells, which are characterized by a common scheme of genome organization and similar developmental regulation. Under certain conditions causing a DNA damage in the bacterial host, a developmental switch, consisting of prophage induction, excision of its genome from the host chromosome, and entering the lytic mode of development, can occur (for reviews see Ptashne 2004; Wegrzyn and Wegrzyn 2005). The best investigated member of this family is bacteriophage λ, which has served as a model virus in molecular biology for some 60 years (Wegrzyn et al 2012) and which is still a useful organism in studies on general biological processes (see, for example, Baranska et al 2013).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
