Genes from the exo-xis region of λ and Shiga toxin-converting bacteriophages influence lysogenization and prophage induction

Arch Microbiol. 2013 Nov;195(10-11):693-703. doi: 10.1007/s00203-013-0920-8. Epub 2013 Aug 27.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacteriophage lambda / genetics*
  • Bacteriophage lambda / physiology
  • Molecular Sequence Data
  • Plasmids
  • Prophages / genetics
  • Prophages / physiology
  • Sequence Alignment
  • Shiga Toxin / genetics
  • Shiga Toxin / metabolism*
  • Shiga-Toxigenic Escherichia coli / genetics
  • Shiga-Toxigenic Escherichia coli / pathogenicity*
  • Shiga-Toxigenic Escherichia coli / physiology
  • Shiga-Toxigenic Escherichia coli / virology*
  • Virus Activation*


  • Shiga Toxin