Role of orf73 in the development of lambdoid bacteriophages during infection of the Escherichia coli host

  • Karolina Zdrojewska Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland https://orcid.org/0000-0001-8891-1236
  • Aleksandra Dydecka Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland https://orcid.org/0000-0003-1248-3508
  • Bożena Nejman-Faleńczyk Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland https://orcid.org/0000-0003-4468-0733
  • Gracja Topka Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland https://orcid.org/0000-0003-4085-4900
  • Agnieszka Necel Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland https://orcid.org/0000-0002-9051-4077
  • Alicja Węgrzyn Laboratory of Molecular Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Gdańsk, Poland
  • Grzegorz Węgrzyn Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland https://orcid.org/0000-0003-4042-7466
  • Sylwia Bloch Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Gdańsk, Poland https://orcid.org/0000-0002-3451-3619

Abstract

Shiga toxin-producing Escherichia coli (STEC) is a group of pathogenic strains responsible for human infections that result in bloody diarrhea and hemorrhagic colitis, often with severe complications. The main virulence factors of STEC are Shiga toxins encoded by stx genes located in genomes of Shiga toxin-converting bacteriophages (Stx phages). These bacterial viruses are clustered in the lambdoid bacteriophages family represented by phage λ. Here, we report that expression of orf73 from the exo-xis region of the phage genome promotes the lysogenic pathway of development of λ and Φ24B phages. We demonstrated that the mutant phages with deletions of orf73 revealed higher burst size during the lytic cycle. Moreover, survival rates of E. coli infected with mutant bacteriophages were lower relative to wild-type viruses. Additionally, orf73 deletion negatively influenced the lysogenization process of E. coli host cells. We conclude that orf73 plays an important biological role in the development of lambdoid viruses, and probably it is involved in the network of molecular mechanism of the lysis-vs.-lysogenization decision.

Published
2019-11-26