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Khan N, Graham T, Franciszkiewicz K, Bloch S, Nejman-Faleńczyk B, Wegrzyn A, Donaldson LW. The NMR structure of the Orf63 lytic developmental protein from lambda bacteriophage. Sci Rep 2024; 14:3793. [PMID: 38360900 PMCID: PMC10869804 DOI: 10.1038/s41598-024-54508-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 02/13/2024] [Indexed: 02/17/2024] Open
Abstract
The orf63 gene resides in a region of the lambda bacteriophage genome between the exo and xis genes and is among the earliest genes transcribed during infection. In lambda phage and Shiga toxin (Stx) producing phages found in enterohemorrhagic Escherichia coli (EHEC) associated with food poisoning, Orf63 expression reduces the host survival and hastens the period between infection and lysis thereby giving it pro-lytic qualities. The NMR structure of dimeric Orf63 reveals a fold consisting of two helices and one strand that all make extensive intermolecular contacts. Structure-based data mining failed to identify any Orf63 homolog beyond the family of temperate bacteriophages. A machine learning approach was used to design an amphipathic helical ligand that bound a hydrophobic cleft on Orf63 with micromolar affinity. This approach may open a new path towards designing therapeutics that antagonize the contributions of Stx phages in EHEC outbreaks.
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Affiliation(s)
- Naushaba Khan
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
| | - Tavawn Graham
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
| | | | - Sylwia Bloch
- Department of Molecular Biology, University of Gdańsk, 80-308, Gdańsk, Poland
| | | | - Alicja Wegrzyn
- Phage Therapy Center, University Center for Applied and Interdisciplinary Research, University of Gdańsk, 80-822, Gdańsk, Poland
| | - Logan W Donaldson
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada.
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2
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Bloch S, Nejman-Faleńczyk B, Licznerska K, Dydecka A, Topka-Bielecka G, Necel A, Węgrzyn A, Węgrzyn G. Complex effects of the exo-xis region of the Shiga toxin-converting bacteriophage Φ24 B genome on the phage development and the Escherichia coli host physiology. J Appl Genet 2024; 65:191-211. [PMID: 37968427 PMCID: PMC10789677 DOI: 10.1007/s13353-023-00799-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/22/2023] [Accepted: 10/23/2023] [Indexed: 11/17/2023]
Abstract
Lambdoid bacteriophages are excellent models in studies on molecular aspects of virus-host interactions. However, some of them carry genes encoding toxins which are responsible for virulence of pathogenic strains of bacteria. Shiga toxin-converting bacteriophages (Stx phages) encode Shiga toxins that cause virulence of enterohemorrhagic Escherichia coli (EHEC), and their effective production depends on Stx prophage induction. The exo-xis region of the lambdoid phage genome consists of genes which are dispensable for the phage multiplication under laboratory conditions; however, they might modulate the virus development. Nevertheless, their exact effects on the phage and host physiology remained unclear. Here, we present results of complex studies on the role of the exo-xis region of bacteriophage Φ24B, one of Stx2b phages. Transcriptomic analyses, together with proteomic and metabolomic studies, provided the basis for understanding the functions of the exo-xis region. Genes from this region promoted lytic development of the phage over lysogenization. Moreover, expression of the host genes coding for DnaK, DnaJ, GrpE, and GroELS chaperones was impaired in the cells infected with the Δexo-xis phage mutant, relative to the wild-type virus, corroborating the conclusion about lytic development promotion by the exo-xis region. Proteomic and metabolomic analyses indicated also modulation of gad and nrf operons, and levels of amino acids and acylcarnitines, respectively. In conclusion, the exo-xis region controls phage propagation and host metabolism by influencing expression of different phage and bacterial genes, directing the virus to the lytic rather than lysogenic developmental mode.
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Affiliation(s)
- Sylwia Bloch
- Department of Molecular Biology, Faculty of Biology, University of Gdansk, Gdansk, Poland
| | | | | | | | | | - Agnieszka Necel
- Department of Medical Microbiology, Faculty of Medicine, Medical University of Gdansk, Gdansk, Poland
| | - Alicja Węgrzyn
- Phage Therapy Center, University Center for Applied and Interdisciplinary Research, University of Gdansk, Gdansk, Poland
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, Faculty of Biology, University of Gdansk, Gdansk, Poland.
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3
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Goddard C, Nejman-Faleńczyk B, Donaldson LW. The NMR structure of the Ea22 lysogenic developmental protein from lambda bacteriophage. Sci Rep 2024; 14:2685. [PMID: 38302537 PMCID: PMC10834534 DOI: 10.1038/s41598-024-52996-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 01/25/2024] [Indexed: 02/03/2024] Open
Abstract
The ea22 gene resides in a relatively uncharacterized region of the lambda bacteriophage genome between the exo and xis genes and is among the earliest genes transcribed upon infection. In lambda and Shiga toxin-producing phages found in enterohemorrhagic E. coli (EHEC) associated with food poisoning, Ea22 favors a lysogenic over lytic developmental state. The Ea22 protein may be considered in terms of three domains: a short amino-terminal domain, a coiled-coiled domain, and a carboxy-terminal domain (CTD). While the full-length protein is tetrameric, the CTD is dimeric when expressed individually. Here, we report the NMR solution structure of the Ea22 CTD that is described by a mixed alpha-beta fold with a dimer interface reinforced by salt bridges. A conserved mobile loop may serve as a ligand for an unknown host protein that works with Ea22 to promote bacterial survival and the formation of new lysogens. From sequence and structural comparisons, the CTD distinguishes lambda Ea22 from homologs encoded by Shiga toxin-producing bacteriophages.
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Affiliation(s)
- Cameron Goddard
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
| | | | - Logan W Donaldson
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada.
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4
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Donaldson LW. Molecular Modeling the Proteins from the exo-xis Region of Lambda and Shigatoxigenic Bacteriophages. Antibiotics (Basel) 2021; 10:1282. [PMID: 34827220 PMCID: PMC8614690 DOI: 10.3390/antibiotics10111282] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/09/2021] [Accepted: 10/19/2021] [Indexed: 11/17/2022] Open
Abstract
Despite decades of intensive research on bacteriophage lambda, a relatively uncharacterized region remains between the exo and xis genes. Collectively, exo-xis region genes are expressed during the earliest stages of the lytic developmental cycle and are capable of affecting the molecular events associated with the lysogenic-lytic developmental decision. In Shiga toxin-producing E. coli (STEC) and enterohemorragic E. coli (EHEC) that are responsible for food- and water-borne outbreaks throughout the world, there are distinct differences of exo-xis region genes from their counterparts in lambda phage. Together, these differences may help EHEC-specific phage and their bacterial hosts adapt to the complex environment within the human intestine. Only one exo-xis region protein, Ea8.5, has been solved to date. Here, I have used the AlphaFold and RoseTTAFold machine learning algorithms to predict the structures of six exo-xis region proteins from lambda and STEC/EHEC phages. Together, the models suggest possible roles for exo-xis region proteins in transcription and the regulation of RNA polymerase.
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5
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Tong J, Nejman-Faleńczyk B, Bloch S, Węgrzyn A, Węgrzyn G, Donaldson LW. Ea22 Proteins from Lambda and Shiga Toxin-Producing Bacteriophages Balance Structural Diversity with Functional Similarity. ACS OMEGA 2020; 5:12236-12244. [PMID: 32548406 PMCID: PMC7271347 DOI: 10.1021/acsomega.0c00894] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) outbreaks are commonly associated with contaminated food sources. Unlike normal intestinal bacteria, EHEC are lysogens of lambdoid bacteriophages that also carry a gene for Shiga toxin. Oxidative attack by the immune system or other stressors on the bacterial host can activate the lytic pathway of the latent phage genome to produce phage progeny and the release of Shiga toxin into the surrounding tissues. Within the genomes of bacteriophage λ and Shiga toxin-expressing (Stx+) phages such as φ24B and φP27, there is a conserved set of open reading frames that is located between the exo and xis genes that influences the lysogenic-lytic decision. In this report, we have focused on the largest exo-xis region open reading frame termed ea22 that has been shown previously to have prolysogenic properties. Using a variety of biophysical and bioinformatic methods, we demonstrate that λ and φP27 Ea22 proteins are tetrameric in solution and can be considered in terms of an amino-terminal region, a central coiled-coil region, and a carboxy-terminal region. The carboxy-terminal regions of λ and φ24B Ea22, expressed on their own, form dimers with exceptional thermostability. Limited proteolysis of φP27 Ea22 also identified a C-terminal region along the predicted boundaries. While the three Ea22 proteins all appear to have the hallmarks of a domain in their respective C-terminal regions, each sequence is remarkably dissimilar. To reconcile this difference among Ea22 proteins from λ and Stx+ phages alike, we speculate that each Ea22 may achieve the same function by targeting different components of the same regulatory process in the host.
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Affiliation(s)
- Jinge Tong
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, Canada M3J 1P3
| | - Bożena Nejman-Faleńczyk
- Department of Molecular Biology, University
of Gdansk, Wita Stwosza
59, 80-308 Gdansk, Poland
| | - Sylwia Bloch
- Department of Molecular Biology, University
of Gdansk, Wita Stwosza
59, 80-308 Gdansk, Poland
| | - Alicja Węgrzyn
- Laboratory of Molecular Biology, Institute
of Biochemistry and Biophysics, Polish Academy
of Sciences, Kładki
24, 80-822 Gdańsk, Poland
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, University
of Gdansk, Wita Stwosza
59, 80-308 Gdansk, Poland
| | - Logan W. Donaldson
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, Canada M3J 1P3
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6
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Dydecka A, Bloch S, Necel A, Topka G, Węgrzyn A, Tong J, Donaldson LW, Węgrzyn G, Nejman-Faleńczyk B. The ea22 gene of lambdoid phages: preserved prolysogenic function despite of high sequence diversity. Virus Genes 2020; 56:266-277. [PMID: 31970620 PMCID: PMC7093339 DOI: 10.1007/s11262-020-01734-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 01/14/2020] [Indexed: 12/22/2022]
Abstract
The exo-xis region of lambdoid phages contains open reading frames and genes that appear to be evolutionarily important. However, this region has received little attention up to now. In this study, we provided evidence that ea22, the largest gene of this region, favors the lysogenic pathway over the lytic pathway in contrast to other characterized exo-xis region genes including ea8.5, orf61, orf60a, and orf63. Our assays also suggest some functional analogies between Ea22 and the phage integrase protein (Int). While it is unsurprising that Ea22 operates similarly in both λ and Stx phages, we have observed some distinctions that may arise from considerable sequence dissimilarity at the carboxy termini of each protein.
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Affiliation(s)
- Aleksandra Dydecka
- Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Sylwia Bloch
- Laboratory of Molecular Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Kładki 24, 80-822, Gdańsk, Poland
| | - Agnieszka Necel
- Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Gracja Topka
- Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Alicja Węgrzyn
- Laboratory of Molecular Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Kładki 24, 80-822, Gdańsk, Poland
| | - Jinge Tong
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
| | - Logan W Donaldson
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Bożena Nejman-Faleńczyk
- Department of Molecular Biology, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland.
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7
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Roles of orf60a and orf61 in Development of Bacteriophages λ and Φ24 B. Viruses 2018; 10:v10100553. [PMID: 30314296 PMCID: PMC6213356 DOI: 10.3390/v10100553] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 10/06/2018] [Accepted: 10/09/2018] [Indexed: 11/30/2022] Open
Abstract
The exo-xis region of lambdoid bacteriophage genomes contains several established and potential genes that are evolutionarily conserved, but not essential for phage propagation under laboratory conditions. Nevertheless, deletion or overexpression of either the whole exo-xis region and important regulatory elements can significantly influence the regulation of phage development. This report defines specific roles for orf60a and orf61 in bacteriophage λ and Φ24B, a specific Shiga toxin-converting phage with clinical relevance. We observed that mutant phages bearing deletions of orf60a and orf61 impaired two central aspects of phage development: the lysis-versus-lysogenization decision and prophage induction. These effects were more pronounced for phage Φ24B than for λ. Surprisingly, adsorption of phage Φ24B on Escherichia coli host cells was less efficient in the absence of either orf60a or orf61. We conclude that these open reading frames (ORFs) play important, but not essential, roles in the regulation of lambdoid phage development. Although phages can propagate without these ORFs in nutrient media, we suggest that they may be involved in the regulatory network, ensuring optimization of phage development under various environmental conditions.
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8
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Dydecka A, Bloch S, Rizvi A, Perez S, Nejman-Falenczyk B, Topka G, Gasior T, Necel A, Wegrzyn G, Donaldson LW, Wegrzyn A. Bad Phages in Good Bacteria: Role of the Mysterious orf63 of λ and Shiga Toxin-Converting Φ24 B Bacteriophages. Front Microbiol 2017; 8:1618. [PMID: 28890713 PMCID: PMC5575149 DOI: 10.3389/fmicb.2017.01618] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 08/08/2017] [Indexed: 11/13/2022] Open
Abstract
Lambdoid bacteriophages form a group of viruses that shares a common schema of genome organization and lifecycle. Some of them can play crucial roles in creating the pathogenic profiles of Escherichia coli strains. For example, Shiga toxin-producing E. coli (STEC) acquired stx genes, encoding Shiga toxins, via lambdoid prophages (Stx phages). The results obtained so far present the evidence for the relation between the exo-xis region of the phage genome and lambdoid phage development, however molecular mechanisms of activities of the exo-xis genes' products are still unknown. In view of this, we decided to determine the influence of the uncharacterized open reading frame orf63 of the exo-xis region on lambdoid phages development using recombinant prophages, λ and Stx phage Φ24B. We have demonstrated that orf63 codes for a folded protein, thus, it is a functional gene. NMR spectroscopy and analytical gel filtration were used to extend this observation further. From backbone chemical shifts, Orf63 is oligomeric in solution, likely a trimer and consistent with its small size (63 aa.), is comprised of two helices, likely intertwined to form the oligomer. We observed that the deletion of phage orf63 does not impair the intracellular lambdoid phage lytic development, however delays the time and decreases the efficiency of prophage induction and in consequence results in increased survival of E. coli during phage lytic development. Additionally, the deletion of phage orf63 negatively influences expression of the major phage genes and open reading frames from the exo-xis region during prophage induction with hydrogen peroxide. We conclude, that lambdoid phage orf63 may have specific functions in the regulation of lambdoid phages development, especially at the stage of the lysis vs. lysogenization decision. Besides, orf63 probably participates in the regulation of the level of expression of essential phage genes and open reading frames from the exo-xis region during prophage induction.
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Affiliation(s)
- Aleksandra Dydecka
- Department of Molecular Biology, Faculty of Biology, University of GdanskGdansk, Poland
| | - Sylwia Bloch
- Department of Molecular Biology, Faculty of Biology, University of GdanskGdansk, Poland
| | - Ali Rizvi
- Department of Biology, York UniversityToronto, ON, Canada
| | - Shaili Perez
- Department of Biology, York UniversityToronto, ON, Canada
| | | | - Gracja Topka
- Department of Molecular Biology, Faculty of Biology, University of GdanskGdansk, Poland
| | - Tomasz Gasior
- Institute of Biochemistry and Biophysics, Polish Academy of SciencesWarsaw, Poland
| | - Agnieszka Necel
- Department of Molecular Biology, Faculty of Biology, University of GdanskGdansk, Poland
| | - Grzegorz Wegrzyn
- Department of Molecular Biology, Faculty of Biology, University of GdanskGdansk, Poland
| | | | - Alicja Wegrzyn
- Institute of Biochemistry and Biophysics, Polish Academy of SciencesWarsaw, Poland
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9
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The Role of the Exo-Xis Region in Oxidative Stress-Mediated Induction of Shiga Toxin-Converting Prophages. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:8453135. [PMID: 26798427 PMCID: PMC4699033 DOI: 10.1155/2016/8453135] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 09/22/2015] [Accepted: 09/28/2015] [Indexed: 11/17/2022]
Abstract
Previous studies indicated that these genetic elements could be involved in the regulation of lysogenization and prophage induction processes. The effects were dramatic in Shiga toxin-converting phage Φ24(B) after treatment with oxidative stress-inducing agent, hydrogen peroxide, while they were less pronounced in bacteriophage λ and in both phages irradiated with UV. The hydrogen peroxide-caused prophage induction was found to be RecA-dependent. Importantly, in hydrogen peroxide-treated E. coli cells lysogenic for either λ or Φ24(B), deletion of the exo-xis region resulted in a significant decrease in the levels of expression of the S.O.S. regulon genes. Moreover, under these conditions, a dramatic decrease in the levels of expression of phage genes crucial for lytic development (particularly xis, exo, N, cro, O, Q, and R) could be observed in Φ24(B)-, but not in λ-bearing cells. We conclude that genes located in the exo-xis region are necessary for efficient expression of both host S.O.S regulon in lysogenic bacteria and regulatory genes of Shiga toxin-converting bacteriophage Φ24(B).
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10
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Personality and genes: remarks from a biological perspective. CURRENT ISSUES IN PERSONALITY PSYCHOLOGY 2014. [DOI: 10.5114/cipp.2014.46229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Although there is no doubt that genes’ functions influence human personality, years of studies provided no clear picture on regulation of particular traits by specific genes. In this article, an overview of the complexity of the system of genetic control of personality is presented, and the level of complications of biological processes operating in this system is underlined. The methodology of studies devoted to determine effects of genes on personality traits is discussed, and limitations of various methods in such studies are indicated. Finally, suggestions for further research are listed and commented on. It is likely that to increase the level of our understanding of genetic mechanisms that modulate human personality, researchers conducting further studies will have to focus on using large sample sizes, performing independent replications, considering experiments on animal models, integrating cross-cultural data and epigenetic measures, and performing interdisciplinary experiments which combine methods of various disciplines, such as biology and psychology.
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11
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Bloch S, Nejman-Faleńczyk B, Dydecka A, Łoś JM, Felczykowska A, Węgrzyn A, Węgrzyn G. Different expression patterns of genes from the exo-xis region of bacteriophage λ and Shiga toxin-converting bacteriophage Ф24B following infection or prophage induction in Escherichia coli. PLoS One 2014; 9:e108233. [PMID: 25310402 PMCID: PMC4195576 DOI: 10.1371/journal.pone.0108233] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 08/28/2014] [Indexed: 11/19/2022] Open
Abstract
Lambdoid bacteriophages serve as useful models in microbiological and molecular studies on basic biological process. Moreover, this family of viruses plays an important role in pathogenesis of enterohemorrhagic Escherichia coli (EHEC) strains, as they are carriers of genes coding for Shiga toxins. Efficient expression of these genes requires lambdoid prophage induction and multiplication of the phage genome. Therefore, understanding the mechanisms regulating these processes appears essential for both basic knowledge and potential anti-EHEC applications. The exo-xis region, present in genomes of lambdoid bacteriophages, contains highly conserved genes of largely unknown functions. Recent report indicated that the Ea8.5 protein, encoded in this region, contains a newly discovered fused homeodomain/zinc-finger fold, suggesting its plausible regulatory role. Moreover, subsequent studies demonstrated that overexpression of the exo-xis region from a multicopy plasmid resulted in impaired lysogenization of E. coli and more effective induction of λ and Ф24B prophages. In this report, we demonstrate that after prophage induction, the increase in phage DNA content in the host cells is more efficient in E. coli bearing additional copies of the exo-xis region, while survival rate of such bacteria is lower, which corroborated previous observations. Importantly, by using quantitative real-time reverse transcription PCR, we have determined patterns of expressions of particular genes from this region. Unexpectedly, in both phages λ and Ф24B, these patterns were significantly different not only between conditions of the host cells infection by bacteriophages and prophage induction, but also between induction of prophages with various agents (mitomycin C and hydrogen peroxide). This may shed a new light on our understanding of regulation of lambdoid phage development, depending on the mode of lytic cycle initiation.
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Affiliation(s)
- Sylwia Bloch
- Department of Molecular Biology, University of Gdańsk, Gdańsk, Poland
| | | | | | - Joanna M. Łoś
- Department of Molecular Biology, University of Gdańsk, Gdańsk, Poland
| | | | - Alicja Węgrzyn
- Department of Microbiology, University of Szczecin, Szczecin, Poland
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, University of Gdańsk, Gdańsk, Poland
- * E-mail:
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12
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Genes from the exo-xis region of λ and Shiga toxin-converting bacteriophages influence lysogenization and prophage induction. Arch Microbiol 2013; 195:693-703. [PMID: 23979561 PMCID: PMC3824215 DOI: 10.1007/s00203-013-0920-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Revised: 07/31/2013] [Accepted: 08/09/2013] [Indexed: 01/17/2023]
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.
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