Abstract
Shiga-toxin producing Escherichia coli (STEC) causes human illness ranging from mild diarrhea to death. The bacteriophage encoded stx genes are located in the late transcription region, downstream of the antiterminator Q. The transcription of the stx genes is directly under the control of the late promoter pR’, thus the sequence diversity of the region between Q and stx, here termed the pR’ region, may affect Stx toxin production. Here, we compared the gene structure of the pR’ region and the stx subtypes of nineteen STECs. The sequence alignment and phylogenetic analysis suggested that the pR’ region tends to be more heterogeneous than the promoter itself, even if the prophages harbor the same stx subtype. Furthermore, we established and validated transcriptional fusions of the pR’ region to the DsRed reporter gene using mitomycin C (MMC) induction. Finally, these constructs were transformed into native and non-native strains and examined with flow cytometry. The results showed that induction levels changed when pR’ regions were placed under different regulatory systems. Moreover, not every stx gene could be induced in its native host bacteria. In addition to the functional genes, the diversity of the pR’ region plays an important role in determining the level of toxin induction.
Highlights
Bacteriophages shape the genome of their prey through horizontal gene transfer, often transferring genes that provide an evolutionary benefit for both the bacterial host and the prophage
There are several examples of this phenomenon in Escherichia coli including phages that transfer genes into E. coli that confer virulence, or improve its ability to survive environmental stress [1–4]. One such group of genes are the stx genes that make E. coli toxic to some protist predators, and convert commensal
∆stx::gfp::ampr was used as the reporter strain for DsRed expression; this strain is a derivative of the outbreak strain E. coli O104:H4 that was obtained by the replacement of stx2a by a gfp::ampr cassette [33]
Summary
Bacteriophages shape the genome of their prey through horizontal gene transfer, often transferring genes that provide an evolutionary benefit for both the bacterial host and the prophage. There are several examples of this phenomenon in Escherichia coli including phages that transfer genes into E. coli that confer virulence, or improve its ability to survive environmental stress [1–4]. One such group of genes are the stx genes that make E. coli toxic to some protist predators, and convert commensal. Shiga toxin-producing E. coli (STEC) cause diarrheal disease [9]. A subpopulation of STEC, enterohemorrhagic E. coli (EHEC), combines Stx production with adhesion to the intestinal mucosa. E. coli O104:H4 combines adhesion factors of enteroaggregative E. coli, which produce attaching and effacing (A/E) lesions with Shiga toxin production [13].
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.
