1
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Ambros CL, Ehrmann MA. Fate, inducibility, and behavior of Latilactobacillus curvatus temperate phage TMW 1.591 P1 during sausage fermentation. J Appl Microbiol 2024; 135:lxae175. [PMID: 38991993 DOI: 10.1093/jambio/lxae175] [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: 02/06/2024] [Revised: 06/28/2024] [Accepted: 07/10/2024] [Indexed: 07/13/2024]
Abstract
AIMS Temperate phages insert their genome into the host's chromosome. As prophages, they remain latent in the genome until an induction event leads to lytic phage production. When this occurs in a starter culture that has been added to food fermentation, this can impair the fermentation success. This study aimed to analyze prophage inducibility in the Latilactobacillus curvatus TMW 1.591 strain during meat fermentation and investigate whether an induction signal before cryopreservation is maintained during storage and can lead to phage-induced lysis after culture activation. METHODS AND RESULTS A prophage-free isogenic derivative of the model starter organism, L. curvatus TMW 1.591, was developed as a negative control (L. curvatus TMW 1.2406). Raw meat fermentation was performed with the wild-type (WT) and phage-cured strains. The WT strain produced high numbers of phages (5.2 ± 1.8 × 107 plaque-forming units g-1) in the meat batter. However, the prophage did not significantly affect the meat fermentation process. Induction experiments suggested an acidic environment as a potential trigger for prophage induction. Phage induction by ultraviolet light before strain cryopreservation remains functional for at least 10 weeks of storage. CONCLUSIONS Intact prophages are active during meat fermentation. However, in this study, this has no measurable consequences for fermentation, suggesting a high resiliency of meat fermentation against phages. Inadequate handling of lysogenic starter strains, even before preservation, can lead to phage introduction into food fermentation and unintended host lysis.
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Affiliation(s)
- Conrad L Ambros
- Chair of Microbiology, Technical University of Munich (TUM), School of Life Sciences, 85354 Freising, Germany
| | - Matthias A Ehrmann
- Chair of Microbiology, Technical University of Munich (TUM), School of Life Sciences, 85354 Freising, Germany
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2
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Adams MC, Schiltz C, Sun J, Hosford C, Johnson V, Pan H, Borbat P, Freed J, Thomason L, Court C, Court D, Chappie J. The crystal structure of bacteriophage λ RexA provides novel insights into the DNA binding properties of Rex-like phage exclusion proteins. Nucleic Acids Res 2024; 52:4659-4675. [PMID: 38554102 PMCID: PMC11077077 DOI: 10.1093/nar/gkae212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 03/07/2024] [Accepted: 03/12/2024] [Indexed: 04/01/2024] Open
Abstract
RexA and RexB function as an exclusion system that prevents bacteriophage T4rII mutants from growing on Escherichia coli λ phage lysogens. Recent data established that RexA is a non-specific DNA binding protein that can act independently of RexB to bias the λ bistable switch toward the lytic state, preventing conversion back to lysogeny. The molecular interactions underlying these activities are unknown, owing in part to a dearth of structural information. Here, we present the 2.05-Å crystal structure of the λ RexA dimer, which reveals a two-domain architecture with unexpected structural homology to the recombination-associated protein RdgC. Modelling suggests that our structure adopts a closed conformation and would require significant domain rearrangements to facilitate DNA binding. Mutagenesis coupled with electromobility shift assays, limited proteolysis, and double electron-electron spin resonance spectroscopy support a DNA-dependent conformational change. In vivo phenotypes of RexA mutants suggest that DNA binding is not a strict requirement for phage exclusion but may directly contribute to modulation of the bistable switch. We further demonstrate that RexA homologs from other temperate phages also dimerize and bind DNA in vitro. Collectively, these findings advance our mechanistic understanding of Rex functions and provide new evolutionary insights into different aspects of phage biology.
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Affiliation(s)
- Myfanwy C Adams
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Carl J Schiltz
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Jing Sun
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | | | - Virginia M Johnson
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Hao Pan
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Peter P Borbat
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
- National Biomedical Resource for Advanced Electron Spin Resonance Spectroscopy, Cornell University, Ithaca, NY 14853, USA
| | - Jack H Freed
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
- National Biomedical Resource for Advanced Electron Spin Resonance Spectroscopy, Cornell University, Ithaca, NY 14853, USA
| | - Lynn C Thomason
- Center for Cancer Research, National Cancer Institute, Frederick, MD21702, USA
| | - Carolyn Court
- Center for Cancer Research, National Cancer Institute, Frederick, MD21702, USA
| | - Donald L Court
- Center for Cancer Research, National Cancer Institute, Frederick, MD21702, USA
| | - Joshua S Chappie
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
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3
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Nyíri K, Gál E, Laczkovich M, Vértessy BG. Antirepressor specificity is shaped by highly efficient dimerization of the staphylococcal pathogenicity island regulating repressors: Stl repressor dimerization perturbed by dUTPases. Sci Rep 2024; 14:1953. [PMID: 38263343 PMCID: PMC10806181 DOI: 10.1038/s41598-024-51260-y] [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: 05/22/2023] [Accepted: 01/02/2024] [Indexed: 01/25/2024] Open
Abstract
The excision and replication, thus the life cycle of pathogenicity islands in staphylococci are regulated by Stl master repressors that form strong dimers. It has been recently shown that SaPIbov1-Stl dimers are separated during the activation of the Staphylococcus aureus pathogenicity island (SaPI) transcription via helper phage proteins. To understand the mechanism of this regulation, a quantitative analysis of the dimerization characteristics is required. Due to the highly efficient dimerization process, such an analysis has to involve specific solutions that permit relevant experiments to be performed. In the present work, we focused on two staphylococcal Stls associated with high biomedical interest, namely Stl proteins of Staphylococcus aureus bov1 and Staphylococcus hominis ShoCI794_SEPI pathogenicity islands. Exploiting the interactions of these two Stl proteins with their antirepressor-mimicking interaction partners allowed precise determination of the Stl dimerization constant in the subnanomolar range.
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Affiliation(s)
- Kinga Nyíri
- Department of Applied Biotechnology and Food Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., Budapest, 1111, Hungary.
- Institute of Molecular Life Sciences, HUN-REN, Research Centre for Natural Sciences, Magyar Tudósok Krt 2., Budapest, 1117, Hungary.
| | - Enikő Gál
- Department of Applied Biotechnology and Food Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., Budapest, 1111, Hungary
- Institute of Molecular Life Sciences, HUN-REN, Research Centre for Natural Sciences, Magyar Tudósok Krt 2., Budapest, 1117, Hungary
| | - Máté Laczkovich
- Department of Applied Biotechnology and Food Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., Budapest, 1111, Hungary
- Institute of Molecular Life Sciences, HUN-REN, Research Centre for Natural Sciences, Magyar Tudósok Krt 2., Budapest, 1117, Hungary
| | - Beáta G Vértessy
- Department of Applied Biotechnology and Food Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., Budapest, 1111, Hungary
- Institute of Molecular Life Sciences, HUN-REN, Research Centre for Natural Sciences, Magyar Tudósok Krt 2., Budapest, 1117, Hungary
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4
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Varming AK, Huang Z, Hamad GM, Rasmussen KK, Ingmer H, Kilstrup M, Lo Leggio L. CI:Mor interactions in the lysogeny switches of Lactococcus lactis TP901-1 and Staphylococcus aureus φ13 bacteriophages. MICROBIOME RESEARCH REPORTS 2024; 3:15. [PMID: 38841409 PMCID: PMC11149083 DOI: 10.20517/mrr.2023.50] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 12/29/2023] [Accepted: 01/09/2024] [Indexed: 06/07/2024]
Abstract
Aim: To structurally characterize in detail the interactions between the phage repressor (CI) and the antirepressor (Mor) in the lysis-lysogeny switches of two Gram-positive bacteriophages, the lactococcal TP901-1 and staphylococcal φ13. Methods: We use crystallographic structure determination, computational structural modeling, and analysis, as well as biochemical methods, to elucidate similarities and differences in the CI:Mor interactions for the two genetic switches. Results: By comparing a newly determined and other available crystal structures for the N-terminal domain of CI (CI-NTD), we show that the CI interface involved in Mor binding undergoes structural changes upon binding in TP901-1. Most importantly, we show experimentally for the first time the direct interaction between CI and Mor for φ13, and model computationally the interaction interface. The computational modeling supports similar side chain rearrangements in TP901-1 and φ13. Conclusion: This study ascertains experimentally that, like in the TP901-1 lysogeny switch, staphylococcal φ13 CI and Mor interact with each other. The structural basis of the interaction of φ13 CI and Mor was computationally modeled and is similar to the interaction demonstrated experimentally between TP901-1 CI-NTD and Mor, likely involving similar rearrangement of residue side chains during the formation of the complex. The study identifies one CI residue, Glu69, which unusually interacts primarily through its aliphatic chain with an aromatic residue on Mor after changing its conformation compared to the un-complexed structure. This and other residues at the interface are suggested for investigation in future studies.
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Affiliation(s)
- Anders K. Varming
- Department of Chemistry, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Zhiyu Huang
- Department of Chemistry, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Ghofran M. Hamad
- Department of Chemistry, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Kim K. Rasmussen
- Department of Chemistry, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg DK-1870, Denmark
| | - Mogens Kilstrup
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby DK-2800, Denmark
| | - Leila Lo Leggio
- Department of Chemistry, University of Copenhagen, Copenhagen DK-2100, Denmark
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5
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Mutate or die: Atomic structures explain bacterial SOS induction. Proc Natl Acad Sci U S A 2023; 120:e2221605120. [PMID: 36693092 PMCID: PMC9945995 DOI: 10.1073/pnas.2221605120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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6
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Abstract
In response to DNA damage, bacterial RecA protein forms filaments with the assistance of DinI protein. The RecA filaments stimulate the autocleavage of LexA, the repressor of more than 50 SOS genes, and activate the SOS response. During the late phase of SOS response, the RecA filaments stimulate the autocleavage of UmuD and λ repressor CI, leading to mutagenic repair and lytic cycle, respectively. Here, we determined the cryo-electron microscopy structures of Escherichia coli RecA filaments in complex with DinI, LexA, UmuD, and λCI by helical reconstruction. The structures reveal that LexA and UmuD dimers bind in the filament groove and cleave in an intramolecular and an intermolecular manner, respectively, while λCI binds deeply in the filament groove as a monomer. Despite their distinct folds and oligomeric states, all RecA filament binders recognize the same conserved protein features in the filament groove. The SOS response in bacteria can lead to mutagenesis and antimicrobial resistance, and our study paves the way for rational drug design targeting the bacterial SOS response.
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7
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King S, Quick A, King K, Walker AR, Shields RC. Activation of TnSmu1, an integrative and conjugative element, by an ImmR-like transcriptional regulator in Streptococcus mutans. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 36201342 DOI: 10.1099/mic.0.001254] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Integrative and conjugative elements (ICEs) are chromosomally encoded mobile genetic elements that can transfer DNA between bacterial strains. Recently, as part of efforts to determine hypothetical gene functions, we have discovered an important regulatory module encoded on an ICE known as TnSmu1 on the Streptococcus mutans chromosome. The regulatory module consists of a cI-like repressor with a helix-turn-helix DNA binding domain immR Smu (immunity repressor) and a metalloprotease immA Smu (anti-repressor). It is not possible to create an in-frame deletion mutant of immR Smu and repression of immR Smu with CRISPRi (CRISPR interference) causes substantial cell defects. We used a bypass of essentiality (BoE) screen to discover genes that allow deletion of the regulatory module. This revealed that conjugation genes, located within TnSmu1, can restore the viability of an immR Smu mutant. Deletion of immR Smu also leads to production of a circular intermediate form of TnSmu1, which is also inducible by the genotoxic agent mitomycin C. To gain further insights into potential regulation of TnSmu1 by ImmRSmu and broader effects on S. mutans UA159 physiology, we used CRISPRi and RNA-seq. Strongly induced genes included all the TnSmu1 mobile element, genes involved in amino acid metabolism, transport systems and a type I-C CRISPR-Cas system. Lastly, bioinformatic analysis shows that the TnSmu1 mobile element and its associated genes are well distributed across S. mutans isolates. Taken together, our results show that activation of TnSmu1 is controlled by the immRA Smu module, and that activation is deleterious to S. mutans, highlighting the complex interplay between mobile elements and their host.
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Affiliation(s)
- Shawn King
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR, USA
| | - Allison Quick
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR, USA
| | - Kalee King
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR, USA
| | | | - Robert C Shields
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR, USA
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8
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Arvidsson I, Tontanahal A, Johansson K, Kristoffersson AC, Kellnerová S, Berger M, Dobrindt U, Karpman D. Apyrase decreases phage induction and Shiga toxin release from E. coli O157:H7 and has a protective effect during infection. Gut Microbes 2022; 14:2122667. [PMID: 36138514 PMCID: PMC9519026 DOI: 10.1080/19490976.2022.2122667] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Shiga toxin (Stx)-producing enterohemorrhagic Escherichia coli (EHEC) cause gastrointestinal infection and, in severe cases, hemolytic uremic syndrome which may lead to death. There is, to-date, no therapy for this infection. Stx induces ATP release from host cells and ATP signaling mediates its cytotoxic effects. Apyrase cleaves and neutralizes ATP and its effect on Stx and EHEC infection was therefore investigated. Apyrase decreased bacterial RecA and dose-dependently decreased toxin release from E. coli O157:H7 in vitro, demonstrated by reduced phage DNA and protein levels. The effect was investigated in a mouse model of E. coli O157:H7 infection. BALB/c mice infected with Stx2-producing E. coli O157:H7 were treated with apyrase intraperitoneally, on days 0 and 2 post-infection, and monitored for 11 days. Apyrase-treated mice developed disease two days later than untreated mice. Untreated infected mice lost significantly more weight than those treated with apyrase. Apyrase-treated mice exhibited less colonic goblet cell depletion and apoptotic cells, as well as lower fecal ATP and Stx2, compared to untreated mice. Apyrase also decreased platelet aggregation induced by co-incubation of human platelet-rich-plasma with Stx2 and E. coli O157 lipopolysaccharide in the presence of collagen. Thus, apyrase had multiple protective effects, reducing RecA levels, stx2 and toxin release from EHEC, reducing fecal Stx2 and protecting mouse intestinal cells, as well as decreasing platelet activation, and could thereby delay the development of disease.
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Affiliation(s)
- Ida Arvidsson
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Ashmita Tontanahal
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Karl Johansson
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden
| | | | - Sára Kellnerová
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden,Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Michael Berger
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Ulrich Dobrindt
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Diana Karpman
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden,CONTACT Diana Karpman Department of Pediatrics, Lund University, 22185Lund, Sweden
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9
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Kaushik V, Tiwari M, Tiwari V. Interaction of RecA mediated SOS response with bacterial persistence, biofilm formation, and host response. Int J Biol Macromol 2022; 217:931-943. [PMID: 35905765 DOI: 10.1016/j.ijbiomac.2022.07.176] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/20/2022] [Accepted: 07/22/2022] [Indexed: 11/28/2022]
Abstract
Antibiotics have a primary mode of actions, and most of them have a common secondary mode of action via reactive species (ROS and RNS) mediated DNA damage. Bacteria have been able to tolerate this DNA damage by SOS (Save-Our-Soul) response. RecA is the universal essential key protein of the DNA damage mediated SOS repair in various bacteria including ESKAPE pathogens. In addition, antibiotics also triggers activation of various other bacterial mechanisms such as biofilm formation, host dependent responses, persister subpopulation formation. These supporting the survival of bacteria in unfriendly natural conditions i.e. antibiotic presence. This review highlights the detailed mechanism of RecA mediated SOS response as well as role of RecA-LexA interaction in SOS response. The review also focuses on inter-connection between DNA damage repair pathway (like SOS response) with other survival mechanisms of bacteria such as host mediated RecA induction, persister-SOS interplay, and biofilm-SOS interplay. This understanding of inter-connection of SOS response with different other survival mechanisms will prove beneficial in targeting the SOS response for prevention and development of therapeutics against recalcitrant bacterial infections. The review also covers the significance of RecA as a promising potent therapeutic target for hindering bacterial SOS response in prevailing successful treatments of bacterial infections and enhancing the conventional antibiotic efficiency.
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Affiliation(s)
- Vaishali Kaushik
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India.
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10
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Boeckman J, Korn A, Yao G, Ravindran A, Gonzalez C, Gill J. Sheep in wolves’ clothing: Temperate T7-like bacteriophages and the origins of the Autographiviridae. Virology 2022; 568:86-100. [DOI: 10.1016/j.virol.2022.01.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/14/2022] [Accepted: 01/22/2022] [Indexed: 12/25/2022]
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11
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Sánchez-Osuna M, Cortés P, Lee M, Smith AT, Barbé J, Erill I. Non-canonical LexA proteins regulate the SOS response in the Bacteroidetes. Nucleic Acids Res 2021; 49:11050-11066. [PMID: 34614190 PMCID: PMC8565304 DOI: 10.1093/nar/gkab773] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 08/18/2021] [Accepted: 10/04/2021] [Indexed: 02/07/2023] Open
Abstract
Lesions to DNA compromise chromosome integrity, posing a direct threat to cell survival. The bacterial SOS response is a widespread transcriptional regulatory mechanism to address DNA damage. This response is coordinated by the LexA transcriptional repressor, which controls genes involved in DNA repair, mutagenesis and cell-cycle control. To date, the SOS response has been characterized in most major bacterial groups, with the notable exception of the Bacteroidetes. No LexA homologs had been identified in this large, diverse and ecologically important phylum, suggesting that it lacked an inducible mechanism to address DNA damage. Here, we report the identification of a novel family of transcriptional repressors in the Bacteroidetes that orchestrate a canonical response to DNA damage in this phylum. These proteins belong to the S24 peptidase family, but are structurally different from LexA. Their N-terminal domain is most closely related to CI-type bacteriophage repressors, suggesting that they may have originated from phage lytic phase repressors. Given their role as SOS regulators, however, we propose to designate them as non-canonical LexA proteins. The identification of a new class of repressors orchestrating the SOS response illuminates long-standing questions regarding the origin and plasticity of this transcriptional network.
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Affiliation(s)
- Miquel Sánchez-Osuna
- Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, 08192 Bellaterra, Spain
| | - Pilar Cortés
- Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, 08192 Bellaterra, Spain
| | - Mark Lee
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Aaron T Smith
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Jordi Barbé
- Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, 08192 Bellaterra, Spain
| | - Ivan Erill
- Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, 08192 Bellaterra, Spain.,Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
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12
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Ansari S, Walsh JC, Bottomley AL, Duggin IG, Burke C, Harry EJ. A newly identified prophage-encoded gene, ymfM, causes SOS-inducible filamentation in Escherichia coli. J Bacteriol 2021; 203:JB.00646-20. [PMID: 33722843 PMCID: PMC8117526 DOI: 10.1128/jb.00646-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 02/26/2021] [Indexed: 12/29/2022] Open
Abstract
Rod-shaped bacteria such as Escherichia coli can regulate cell division in response to stress, leading to filamentation, a process where cell growth and DNA replication continues in the absence of division, resulting in elongated cells. The classic example of stress is DNA damage which results in the activation of the SOS response. While the inhibition of cell division during SOS has traditionally been attributed to SulA in E. coli, a previous report suggests that the e14 prophage may also encode an SOS-inducible cell division inhibitor, previously named SfiC. However, the exact gene responsible for this division inhibition has remained unknown for over 35 years. A recent high-throughput over-expression screen in E. coli identified the e14 prophage gene, ymfM, as a potential cell division inhibitor. In this study, we show that the inducible expression of ymfM from a plasmid causes filamentation. We show that this expression of ymfM results in the inhibition of Z ring formation and is independent of the well characterised inhibitors of FtsZ ring assembly in E. coli, SulA, SlmA and MinC. We confirm that ymfM is the gene responsible for the SfiC phenotype as it contributes to the filamentation observed during the SOS response. This function is independent of SulA, highlighting that multiple alternative division inhibition pathways exist during the SOS response. Our data also highlight that our current understanding of cell division regulation during the SOS response is incomplete and raises many questions regarding how many inhibitors there actually are and their purpose for the survival of the organism.Importance:Filamentation is an important biological mechanism which aids in the survival, pathogenesis and antibiotic resistance of bacteria within different environments, including pathogenic bacteria such as uropathogenic Escherichia coli Here we have identified a bacteriophage-encoded cell division inhibitor which contributes to the filamentation that occurs during the SOS response. Our work highlights that there are multiple pathways that inhibit cell division during stress. Identifying and characterising these pathways is a critical step in understanding survival tactics of bacteria which become important when combating the development of bacterial resistance to antibiotics and their pathogenicity.
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Affiliation(s)
- Shirin Ansari
- The ithree institute, Faculty of Science, University of Technology Sydney, Sydney, Australia
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - James C Walsh
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Amy L Bottomley
- The ithree institute, Faculty of Science, University of Technology Sydney, Sydney, Australia
| | - Iain G Duggin
- The ithree institute, Faculty of Science, University of Technology Sydney, Sydney, Australia
| | - Catherine Burke
- The ithree institute, Faculty of Science, University of Technology Sydney, Sydney, Australia
| | - Elizabeth J Harry
- The ithree institute, Faculty of Science, University of Technology Sydney, Sydney, Australia
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13
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Chen B, Chen Z, Wang Y, Gong H, Sima L, Wang J, Ouyang S, Gan W, Krupovic M, Chen X, Du S. ORF4 of the Temperate Archaeal Virus SNJ1 Governs the Lysis-Lysogeny Switch and Superinfection Immunity. J Virol 2020; 94:e00841-20. [PMID: 32522850 PMCID: PMC7394903 DOI: 10.1128/jvi.00841-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/01/2020] [Indexed: 12/21/2022] Open
Abstract
Recent environmental and metagenomic studies have considerably increased the repertoire of archaeal viruses and suggested that they play important roles in nutrient cycling in the biosphere. However, very little is known about how they regulate their life cycles and interact with their hosts. Here, we report that the life cycle of the temperate haloarchaeal virus SNJ1 is controlled by the product ORF4, a small protein belonging to the antitoxin MazE superfamily. We show that ORF4 controls the lysis-lysogeny switch of SNJ1 and mediates superinfection immunity by repression of genomic DNA replication of the superinfecting viruses. Bioinformatic analysis shows that ORF4 is highly conserved in two SNJ1-like proviruses, suggesting that the mechanisms for lysis-lysogeny switch and superinfection immunity are conserved in this group of viruses. As the lysis-lysogeny switch and superinfection immunity of archaeal viruses have been poorly studied, we suggest that SNJ1 could serve as a model system to study these processes.IMPORTANCE Archaeal viruses are important parts of the virosphere. Understanding how they regulate their life cycles and interact with host cells provide crucial insights into their biological functions and the evolutionary histories of viruses. However, mechanistic studies of the life cycle of archaeal viruses are scarce due to a lack of genetic tools and demanding cultivation conditions. Here, we discover that the temperate haloarchaeal virus SNJ1, which infects Natrinema sp. strain J7, employs a lysis-lysogeny switch and establishes superinfection immunity like bacteriophages. We show that its ORF4 is critical for both processes and acts as a repressor of the replication of SNJ1. These results establish ORF4 as a master regulator of SNJ1 life cycle and provides novel insights on the regulation of life cycles by temperate archaeal viruses and on their interactions with host cells.
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Affiliation(s)
- Beibei Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhao Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yuchen Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Han Gong
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Linshan Sima
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jiao Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Shushan Ouyang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Wenqiang Gan
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Mart Krupovic
- Department of Microbiology, Institut Pasteur, Paris, France
| | - Xiangdong Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Shishen Du
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
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14
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Ghodke H, Paudel BP, Lewis JS, Jergic S, Gopal K, Romero ZJ, Wood EA, Woodgate R, Cox MM, van Oijen AM. Spatial and temporal organization of RecA in the Escherichia coli DNA-damage response. eLife 2019; 8:42761. [PMID: 30717823 PMCID: PMC6363387 DOI: 10.7554/elife.42761] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 01/22/2019] [Indexed: 12/14/2022] Open
Abstract
The RecA protein orchestrates the cellular response to DNA damage via its multiple roles in the bacterial SOS response. Lack of tools that provide unambiguous access to the various RecA states within the cell have prevented understanding of the spatial and temporal changes in RecA structure/function that underlie control of the damage response. Here, we develop a monomeric C-terminal fragment of the λ repressor as a novel fluorescent probe that specifically interacts with RecA filaments on single-stranded DNA (RecA*). Single-molecule imaging techniques in live cells demonstrate that RecA is largely sequestered in storage structures during normal metabolism. Upon DNA damage, the storage structures dissolve and the cytosolic pool of RecA rapidly nucleates to form early SOS-signaling complexes, maturing into DNA-bound RecA bundles at later time points. Both before and after SOS induction, RecA* largely appears at locations distal from replisomes. Upon completion of repair, RecA storage structures reform.
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Affiliation(s)
- Harshad Ghodke
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Bishnu P Paudel
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Jacob S Lewis
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Slobodan Jergic
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.,Illawarra Health and Medical Research Institute, Wollongong, Australia
| | - Kamya Gopal
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Zachary J Romero
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Elizabeth A Wood
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Roger Woodgate
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
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15
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The osnR gene of Corynebacterium glutamicum plays a negative regulatory role in oxidative stress responses. ACTA ACUST UNITED AC 2019; 46:241-248. [DOI: 10.1007/s10295-018-02126-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 12/20/2018] [Indexed: 11/26/2022]
Abstract
Abstract
Among the Corynebacterium glutamicum ORFs that have been implicated in stress responses, we chose ORF cg3230, designated osnR, and analyzed it further. Unlike the osnR-deleted strain (ΔosnR), the osnR-overexpressing strain (P180-osnR) developed growth defects and increased sensitivity to various oxidants including H2O2. Transcription in the P180-osnR strain of genes such as sodA (superoxide dismutase), ftn (ferritin biosynthesis), and ahpD (alkyl hydroperoxide reductase; cg2674), which are involved in the detoxification of reactive oxygen species, was only 40% that of the wild type. However, transcription of katA, encoding H2O2-detoxifying catalase, was unchanged in this strain. Genes such as trxB (thioredoxin reductase) and mtr (mycothiol disulfide reductase), which play roles in redox homeostasis, also showed decreased transcription in the strain. 2D-PAGE analysis indicated that genes involved in redox reactions were considerably affected by osnR overexpression. The NADPH/NADP+ ratio of the P180-osnR strain (1.35) was higher than that of the wild-type stain (0.78). Collectively, the phenotypes of the ΔosnR and P180-osnR strains suggest a global regulatory role as well as a negative role for the gene in stress responses, particularly in katA-independent oxidative stress responses.
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16
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Tomazou M, Barahona M, Polizzi KM, Stan GB. Computational Re-design of Synthetic Genetic Oscillators for Independent Amplitude and Frequency Modulation. Cell Syst 2018; 6:508-520.e5. [PMID: 29680377 DOI: 10.1016/j.cels.2018.03.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 12/14/2017] [Accepted: 03/19/2018] [Indexed: 01/27/2023]
Abstract
To perform well in biotechnology applications, synthetic genetic oscillators must be engineered to allow independent modulation of amplitude and period. This need is currently unmet. Here, we demonstrate computationally how two classic genetic oscillators, the dual-feedback oscillator and the repressilator, can be re-designed to provide independent control of amplitude and period and improve tunability-that is, a broad dynamic range of periods and amplitudes accessible through the input "dials." Our approach decouples frequency and amplitude modulation by incorporating an orthogonal "sink module" where the key molecular species are channeled for enzymatic degradation. This sink module maintains fast oscillation cycles while alleviating the translational coupling between the oscillator's transcription factors and output. We characterize the behavior of our re-designed oscillators over a broad range of physiologically reasonable parameters, explain why this facilitates broader function and control, and provide general design principles for building synthetic genetic oscillators that are more precisely controllable.
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Affiliation(s)
- Marios Tomazou
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK; Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK
| | - Mauricio Barahona
- Department of Mathematics, Imperial College London, London SW7 2AZ, UK; Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK
| | - Karen M Polizzi
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK; Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK
| | - Guy-Bart Stan
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK; Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK.
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17
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Specifically bound lambda repressor dimers promote adjacent non-specific binding. PLoS One 2018; 13:e0194930. [PMID: 29608611 PMCID: PMC5880393 DOI: 10.1371/journal.pone.0194930] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 03/13/2018] [Indexed: 01/01/2023] Open
Abstract
Genetic switches frequently include DNA loops secured by proteins. Recent studies of the lambda bacteriophage repressor (CI), showed that this arrangement in which the protein links two sets of three operators separated by approximately 2.3 kbp, optimizes both the stability and dynamics of DNA loops, compared to an arrangement with just two sets of two operators. Because adjacent dimers interact pairwise, we hypothesized that the odd number of operators in each set of the lambda regulatory system might have evolved to allow for semi-specific, pair-wise interactions that add stability to the loop while maintaining it dynamic. More generally, additional CI dimers may bind non-specifically to flanking DNA sequences making the genetic switch more sensitive to CI concentration. Here, we tested this hypothesis using spectroscopic and imaging approaches to study the binding of the lambda repressor (CI) dimer protein to DNA fragments. For fragments with only one operator and a short flanking sequence, fluorescence correlation spectroscopy measurements clearly indicated the presence of two distinct DNA-CI complexes; one is thought to have a non-specifically bound CI dimer on the flanking sequence. Scanning force micrographs of CI bound to DNA with all six operators revealed wild-type or mutant proteins bound at operator positions. The number of bound, wild-type proteins increased with CI concentration and was larger than expected for strictly specific binding to operators. In contrast, a mutant that fails to oligomerize beyond a dimer, D197G, only bound to operators. These data are evidence that CI cooperativity promotes oligomerization that extends from operator sites to influence the thermodynamics and kinetics of CI-mediated looping.
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18
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Kaur J, Kumar A, Kaur J. Strategies for optimization of heterologous protein expression in E. coli: Roadblocks and reinforcements. Int J Biol Macromol 2018; 106:803-822. [DOI: 10.1016/j.ijbiomac.2017.08.080] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 08/02/2017] [Accepted: 08/12/2017] [Indexed: 12/29/2022]
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19
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Kaur J, Kumar A, Kaur J. Strategies for optimization of heterologous protein expression in E. coli: Roadblocks and reinforcements. Int J Biol Macromol 2018. [DOI: 10.1016/j.ijbiomac.2017.08.080 10.1242/jeb.069716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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20
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Valle A, Hervis Y, Socas L, Canet L, Faheem M, Barbosa J, Lanio M, Pazos I. The multigene families of actinoporins (part II): Strategies for heterologous production in Escherichia coli. Toxicon 2016; 118:64-81. [DOI: 10.1016/j.toxicon.2016.03.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/24/2016] [Indexed: 11/26/2022]
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21
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Koberg S, Mohamed MDA, Faulhaber K, Neve H, Heller KJ. Identification and characterization of cis- and trans-acting elements involved in prophage induction in Streptococcus thermophilus J34. Mol Microbiol 2015; 98:535-52. [PMID: 26193959 DOI: 10.1111/mmi.13140] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2015] [Indexed: 11/29/2022]
Abstract
The genetic switch region of temperate Streptococcus thermophilus phage TP-J34 contains two divergently oriented promoters and several predicted operator sites. It separates lytic cycle-promoting genes from those promoting lysogeny. A polycistronic transcript comprises the genes coding for repressor Crh, metalloproteinase-motif protein Rir and superinfection exclusion lipoprotein Ltp. Weak promoters effecting monocistronic transcripts were localized for ltp and int (encoding integrase) by Northern blot and 5'-RACE-PCR. These transcripts appeared in lysogenic as well as lytic state. A polycistronic transcript comprising genes coh (encoding Cro homolog), ant (encoding putative antirepressor), orf7, orf8 and orf9 was only detected in the lytic state. Four operator sites, of which three were located in the intergenic regions between crh and coh, and one between coh and ant, were identified by competition electromobility shift assays. Cooperative binding of Crh to two operator sites immediately upstream of coh could be demonstrated. Coh was shown to bind to the operator closest to crh only. Oligomerization was proven by cross-linking Crh by glutaraldehyde. Knock-out of rir revealed a key role in prophage induction. Rir and Crh were shown to form a complex in solution and Rir prevented binding of Crh to its operator sites.
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Affiliation(s)
- Sabrina Koberg
- Department of Microbiology and Biotechnology, Max Rubner-Institut (Federal Research Institute of Nutrition and Food), Kiel, Germany
| | - Mazhar Desouki Ali Mohamed
- Department of Microbiology and Biotechnology, Max Rubner-Institut (Federal Research Institute of Nutrition and Food), Kiel, Germany
| | - Katharina Faulhaber
- Department of Microbiology and Biotechnology, Max Rubner-Institut (Federal Research Institute of Nutrition and Food), Kiel, Germany
| | - Horst Neve
- Department of Microbiology and Biotechnology, Max Rubner-Institut (Federal Research Institute of Nutrition and Food), Kiel, Germany
| | - Knut J Heller
- Department of Microbiology and Biotechnology, Max Rubner-Institut (Federal Research Institute of Nutrition and Food), Kiel, Germany
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22
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Fricker AD, Peters JE. Vulnerabilities on the lagging-strand template: opportunities for mobile elements. Annu Rev Genet 2014; 48:167-86. [PMID: 25195506 DOI: 10.1146/annurev-genet-120213-092046] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mobile genetic elements have the ability to move between positions in a genome. Some of these elements are capable of targeting one of the template strands during DNA replication. Examples found in bacteria include (a) Red recombination mediated by bacteriophage λ, (b) integration of group II mobile introns that reverse splice and reverse transcribe into DNA, (c) HUH endonuclease elements that move as single-stranded DNA, and (d) Tn7, a DNA cut-and-paste transposon that uses a target-site-selecting protein to target transposition into certain forms of DNA replication. In all of these examples, the lagging-strand template appears to be targeted using a variety of features specific to this strand. These features appear especially available in certain situations, such as when replication forks stall or collapse. In this review, we address the idea that features specific to the lagging-strand template represent vulnerabilities that are capitalized on by mobile genetic elements.
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Affiliation(s)
- Ashwana D Fricker
- Department of Microbiology, Cornell University, Ithaca, New York 14853;
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23
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Rosano GL, Ceccarelli EA. Recombinant protein expression in Escherichia coli: advances and challenges. Front Microbiol 2014; 5:172. [PMID: 24860555 PMCID: PMC4029002 DOI: 10.3389/fmicb.2014.00172] [Citation(s) in RCA: 1299] [Impact Index Per Article: 129.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 03/29/2014] [Indexed: 12/28/2022] Open
Abstract
Escherichia coli is one of the organisms of choice for the production of recombinant proteins. Its use as a cell factory is well-established and it has become the most popular expression platform. For this reason, there are many molecular tools and protocols at hand for the high-level production of heterologous proteins, such as a vast catalog of expression plasmids, a great number of engineered strains and many cultivation strategies. We review the different approaches for the synthesis of recombinant proteins in E. coli and discuss recent progress in this ever-growing field.
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Affiliation(s)
- Germán L Rosano
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas Rosario, Argentina ; Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario Rosario, Argentina
| | - Eduardo A Ceccarelli
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas Rosario, Argentina ; Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario Rosario, Argentina
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24
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Nassar FJ, Rahal EA, Sabra A, Matar GM. Effects of subinhibitory concentrations of antimicrobial agents on Escherichia coli O157:H7 Shiga toxin release and role of the SOS response. Foodborne Pathog Dis 2013; 10:805-12. [PMID: 23808851 DOI: 10.1089/fpd.2013.1510] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Treatment of Escherichia coli O157:H7 by certain antimicrobial agents often exacerbates the patient's condition by increasing either the release of preformed Shiga toxins (Stx) upon cell lysis or their production through the SOS response-triggered induction of Stx-producing prophages. Recommended subinhibitory concentrations (sub-MICs) of azithromycin (AZI), gentamicin (GEN), imipenem (IMI), and rifampicin (RIF) were evaluated in comparison to norfloxacin (NOR), an SOS-inducer, to assess the role of the SOS response in Stx release. Relative expression of recA (SOS-inducer), Q (late antitermination gene of Stx-producing prophage), stx1, and stx2 genes was assessed at two sub-MICs of the antimicrobials for two different strains of E. coli O157:H7 using reverse transcription-real-time polymerase chain reaction. Both strains at the two sub-MICs were also subjected to Western blotting for LexA protein expression and to reverse passive latex agglutination for Stx detection. For both strains at both sub-MICs, NOR and AZI caused SOS-induced Stx production (high recA, Q, and stx2 gene expression and high Stx2 production), so they should be avoided in E. coli O157:H7 treatment; however, sub-MICs of RIF and IMI induced Stx2 production in an SOS-independent manner except for one strain at the first twofold dilution below MIC of RIF where Stx2 production decreased. Moreover, GEN caused somewhat increased Stx2 production due to its mode of action rather than any effect on gene expression. The choice of antimicrobial therapy should rely on the antimicrobial mode of action, its concentration, and on the nature of the strain.
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Affiliation(s)
- Farah J Nassar
- Department of Experimental Pathology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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25
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Busygina V, Gaines WA, Xu Y, Kwon Y, Williams GJ, Lin SW, Chang HY, Chi P, Wang HW, Sung P. Functional attributes of the Saccharomyces cerevisiae meiotic recombinase Dmc1. DNA Repair (Amst) 2013; 12:707-12. [PMID: 23769192 DOI: 10.1016/j.dnarep.2013.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 05/15/2013] [Accepted: 05/17/2013] [Indexed: 01/10/2023]
Abstract
The role of Dmc1 as a meiosis-specific general recombinase was first demonstrated in Saccharomyces cerevisiae. Progress in understanding the biochemical mechanism of ScDmc1 has been hampered by its tendency to form inactive aggregates. We have found that the inclusion of ATP during protein purification prevents Dmc1 aggregation. ScDmc1 so prepared is capable of forming D-loops and responsive to its accessory factors Rad54 and Rdh54. Negative staining electron microscopy and iterative helical real-space reconstruction revealed that the ScDmc1-ssDNA nucleoprotein filament harbors 6.5 protomers per turn with a pitch of ∼106Å. The ScDmc1 purification procedure and companion molecular analyses should facilitate future studies on this recombinase.
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Affiliation(s)
- Valeria Busygina
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
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26
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Abstract
Homologous recombination is an ubiquitous process that shapes genomes and repairs DNA damage. The reaction is classically divided into three phases: presynaptic, synaptic, and postsynaptic. In Escherichia coli, the presynaptic phase involves either RecBCD or RecFOR proteins, which act on DNA double-stranded ends and DNA single-stranded gaps, respectively; the central synaptic steps are catalyzed by the ubiquitous DNA-binding protein RecA; and the postsynaptic phase involves either RuvABC or RecG proteins, which catalyze branch-migration and, in the case of RuvABC, the cleavage of Holliday junctions. Here, we review the biochemical properties of these molecular machines and analyze how, in light of these properties, the phenotypes of null mutants allow us to define their biological function(s). The consequences of point mutations on the biochemical properties of recombination enzymes and on cell phenotypes help refine the molecular mechanisms of action and the biological roles of recombination proteins. Given the high level of conservation of key proteins like RecA and the conservation of the principles of action of all recombination proteins, the deep knowledge acquired during decades of studies of homologous recombination in bacteria is the foundation of our present understanding of the processes that govern genome stability and evolution in all living organisms.
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27
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Li Z, Stevens DL, Hamilton SM, Parimon T, Ma Y, Kearns AM, Ellis RW, Bryant AE. Fatal S. aureus hemorrhagic pneumonia: genetic analysis of a unique clinical isolate producing both PVL and TSST-1. PLoS One 2011; 6:e27246. [PMID: 22110621 PMCID: PMC3207839 DOI: 10.1371/journal.pone.0027246] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 10/12/2011] [Indexed: 02/02/2023] Open
Abstract
In 2008, an unusual strain of methicillin-sensitive Staphylococcus aureus (MSSA68111), producing both Panton-Valentine leukocidin (PVL) and toxic shock syndrome toxin-1 (TSST-1), was isolated from a fatal case of necrotizing pneumonia. Because PVL/TSST-1 co-production in S. aureus is rare, we characterized the molecular organization of these toxin genes in strain 68111. MSSA68111 carries the PVL genes within a novel temperate prophage we call ФPVLv68111 that is most similar, though not identical, to phage ФPVL--a phage type that is relatively rare worldwide. The TSST-1 gene (tst) in MSSA68111 is carried on a unique staphylococcal pathogenicity island (SaPI) we call SaPI68111. Features of SaPI68111 suggest it likely arose through multiple major recombination events with other known SaPIs. Both ФPVLv68111 and SaPI68111 are fully mobilizable and therefore transmissible to other strains. Taken together, these findings suggest that hypervirulent S. aureus have the potential to emerge worldwide.
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Affiliation(s)
- Zhi Li
- Veterans Affairs Medical Center, Boise, Idaho, United States of America.
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28
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Adikesavan AK, Katsonis P, Marciano DC, Lua R, Herman C, Lichtarge O. Separation of recombination and SOS response in Escherichia coli RecA suggests LexA interaction sites. PLoS Genet 2011; 7:e1002244. [PMID: 21912525 PMCID: PMC3164682 DOI: 10.1371/journal.pgen.1002244] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 06/29/2011] [Indexed: 12/29/2022] Open
Abstract
RecA plays a key role in homologous recombination, the induction of the DNA damage response through LexA cleavage and the activity of error-prone polymerase in Escherichia coli. RecA interacts with multiple partners to achieve this pleiotropic role, but the structural location and sequence determinants involved in these multiple interactions remain mostly unknown. Here, in a first application to prokaryotes, Evolutionary Trace (ET) analysis identifies clusters of evolutionarily important surface amino acids involved in RecA functions. Some of these clusters match the known ATP binding, DNA binding, and RecA-RecA homo-dimerization sites, but others are novel. Mutation analysis at these sites disrupted either recombination or LexA cleavage. This highlights distinct functional sites specific for recombination and DNA damage response induction. Finally, our analysis reveals a composite site for LexA binding and cleavage, which is formed only on the active RecA filament. These new sites can provide new drug targets to modulate one or more RecA functions, with the potential to address the problem of evolution of antibiotic resistance at its root. In eubacteria, genome integrity is in large part orchestrated by RecA, which directly participates in recombination, induction of DNA damage response through LexA repressor cleavage and error-prone DNA synthesis. Yet, most of the interaction sites necessary for these vital processes are largely unknown. By comparing divergences among RecA sequences and computing putative functional regions, we discovered four functional sites of RecA. Targeted point-mutations were then tested for both recombination and DNA damage induction and reveal distinct RecA functions at each one of these sites. In particular, one new set of mutants is deficient in promoting LexA cleavage and yet maintains the ability to induce the DNA damage response. These results reveal specific amino acid determinants of the RecA–LexA interaction and suggest that LexA binds RecAi and RecAi+6 at a composite site on the RecA filament, which could explain the role of the active filament during LexA cleavage.
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Affiliation(s)
- Anbu K Adikesavan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
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29
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Lemire S, Figueroa-Bossi N, Bossi L. Bacteriophage crosstalk: coordination of prophage induction by trans-acting antirepressors. PLoS Genet 2011; 7:e1002149. [PMID: 21731505 PMCID: PMC3121763 DOI: 10.1371/journal.pgen.1002149] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 05/05/2011] [Indexed: 02/01/2023] Open
Abstract
Many species of bacteria harbor multiple prophages in their genomes. Prophages often carry genes that confer a selective advantage to the bacterium, typically during host colonization. Prophages can convert to infectious viruses through a process known as induction, which is relevant to the spread of bacterial virulence genes. The paradigm of prophage induction, as set by the phage Lambda model, sees the process initiated by the RecA-stimulated self-proteolysis of the phage repressor. Here we show that a large family of lambdoid prophages found in Salmonella genomes employs an alternative induction strategy. The repressors of these phages are not cleaved upon induction; rather, they are inactivated by the binding of small antirepressor proteins. Formation of the complex causes the repressor to dissociate from DNA. The antirepressor genes lie outside the immunity region and are under direct control of the LexA repressor, thus plugging prophage induction directly into the SOS response. GfoA and GfhA, the antirepressors of Salmonella prophages Gifsy-1 and Gifsy-3, each target both of these phages' repressors, GfoR and GfhR, even though the latter proteins recognize different operator sites and the two phages are heteroimmune. In contrast, the Gifsy-2 phage repressor, GtgR, is insensitive to GfoA and GfhA, but is inactivated by an antirepressor from the unrelated Fels-1 prophage (FsoA). This response is all the more surprising as FsoA is under the control of the Fels-1 repressor, not LexA, and plays no apparent role in Fels-1 induction, which occurs via a Lambda CI-like repressor cleavage mechanism. The ability of antirepressors to recognize non-cognate repressors allows coordination of induction of multiple prophages in polylysogenic strains. Identification of non-cleavable gfoR/gtgR homologues in a large variety of bacterial genomes (including most Escherichia coli genomes in the DNA database) suggests that antirepression-mediated induction is far more common than previously recognized.
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Affiliation(s)
- Sébastien Lemire
- Centre de Génétique Moléculaire, CNRS, UPR3404, Université Paris-Sud, Gif-sur-Yvette, France
| | - Nara Figueroa-Bossi
- Centre de Génétique Moléculaire, CNRS, UPR3404, Université Paris-Sud, Gif-sur-Yvette, France
| | - Lionello Bossi
- Centre de Génétique Moléculaire, CNRS, UPR3404, Université Paris-Sud, Gif-sur-Yvette, France
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30
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Butala M, Klose D, Hodnik V, Rems A, Podlesek Z, Klare JP, Anderluh G, Busby SJW, Steinhoff HJ, Zgur-Bertok D. Interconversion between bound and free conformations of LexA orchestrates the bacterial SOS response. Nucleic Acids Res 2011; 39:6546-57. [PMID: 21576225 PMCID: PMC3159453 DOI: 10.1093/nar/gkr265] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The bacterial SOS response is essential for the maintenance of genomes, and also modulates antibiotic resistance and controls multidrug tolerance in subpopulations of cells known as persisters. In Escherichia coli, the SOS system is controlled by the interplay of the dimeric LexA transcriptional repressor with an inducer, the active RecA filament, which forms at sites of DNA damage and activates LexA for self-cleavage. Our aim was to understand how RecA filament formation at any chromosomal location can induce the SOS system, which could explain the mechanism for precise timing of induction of SOS genes. Here, we show that stimulated self-cleavage of the LexA repressor is prevented by binding to specific DNA operator targets. Distance measurements using pulse electron paramagnetic resonance spectroscopy reveal that in unbound LexA, the DNA-binding domains sample different conformations. One of these conformations is captured when LexA is bound to operator targets and this precludes interaction by RecA. Hence, the conformational flexibility of unbound LexA is the key element in establishing a co-ordinated SOS response. We show that, while LexA exhibits diverse dissociation rates from operators, it interacts extremely rapidly with DNA target sites. Modulation of LexA activity changes the occurrence of persister cells in bacterial populations.
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Affiliation(s)
- Matej Butala
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia.
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Folded DNA in action: hairpin formation and biological functions in prokaryotes. Microbiol Mol Biol Rev 2011; 74:570-88. [PMID: 21119018 DOI: 10.1128/mmbr.00026-10] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Structured forms of DNA with intrastrand pairing are generated in several cellular processes and are involved in biological functions. These structures may arise on single-stranded DNA (ssDNA) produced during replication, bacterial conjugation, natural transformation, or viral infections. Furthermore, negatively supercoiled DNA can extrude inverted repeats as hairpins in structures called cruciforms. Whether they are on ssDNA or as cruciforms, hairpins can modify the access of proteins to DNA, and in some cases, they can be directly recognized by proteins. Folded DNAs have been found to play an important role in replication, transcription regulation, and recognition of the origins of transfer in conjugative elements. More recently, they were shown to be used as recombination sites. Many of these functions are found on mobile genetic elements likely to be single stranded, including viruses, plasmids, transposons, and integrons, thus giving some clues as to the manner in which they might have evolved. We review here, with special focus on prokaryotes, the functions in which DNA secondary structures play a role and the cellular processes giving rise to them. Finally, we attempt to shed light on the selective pressures leading to the acquisition of functions for DNA secondary structures.
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Song Q, Ye T, Zhang X. Proteins responsible for lysogeny of deep-sea thermophilic bacteriophage GVE2 at high temperature. Gene 2011; 479:1-9. [PMID: 21303688 DOI: 10.1016/j.gene.2011.01.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Revised: 01/19/2011] [Accepted: 01/20/2011] [Indexed: 10/18/2022]
Abstract
The lytic and lysogenic life cycle switch of bacteriophages plays very important roles in virus-host interactions. However, the lysogeny of thermophilic bacteriophage infecting thermophile at high temperatures has not been addressed. In this study, two lysogeny-related genes encoding the CI protein and recombinase of GVE2, a thermophilic bacteriophage obtained from a deep-sea hydrothermal vent, were characterized. Temporal analyses showed that the two genes were expressed at early stages of GVE2 infection. Based on chromatin immunoprecipitation (ChIP) assay and electrophoretic mobility shift assay (EMSA), the GVE2 CI protein was bound with only one DNA fragment located at 24264-24036 bp in the GVE2 genome. This location might be the original transcription site and the lysis-lysogeny switch site, which was very different from mesophilic bacteriophages. The GVE2 CI and recombinase proteins could function only at high temperatures. Therefore our study improved our understanding of the lysogeny process of bacteriophages at high temperatures.
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Affiliation(s)
- Qing Song
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, People's Republic of China
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Comparative transcriptomic and phenotypic analysis of the responses of Bacillus cereus to various disinfectant treatments. Appl Environ Microbiol 2010; 76:3352-60. [PMID: 20348290 DOI: 10.1128/aem.03003-09] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial chemicals are widely applied to clean and disinfect food-contacting surfaces. However, the cellular response of bacteria to various disinfectants is unclear. In this study, the physiological and genome-wide transcriptional responses of Bacillus cereus ATCC 14579 exposed to four different disinfectants (benzalkonium chloride, sodium hypochlorite, hydrogen peroxide, and peracetic acid) were analyzed. For each disinfectant, concentrations leading to the attenuation of growth, growth arrest, and cell death were determined. The transcriptome analysis revealed that B. cereus, upon exposure to the selected concentrations of disinfectants, induced common and specific responses. Notably, the common response included genes involved in the general and oxidative stress responses. Exposure to benzalkonium chloride, a disinfectant known to induce membrane damage, specifically induced genes involved in fatty acid metabolism. Membrane damage induced by benzalkonium chloride was confirmed by fluorescence microscopy, and fatty acid analysis revealed modulation of the fatty acid composition of the cell membrane. Exposure to sodium hypochlorite induced genes involved in metabolism of sulfur and sulfur-containing amino acids, which correlated with the excessive oxidation of sulfhydryl groups observed in sodium hypochlorite-stressed cells. Exposures to hydrogen peroxide and peracetic acid induced highly similar responses, including the upregulation of genes involved in DNA damage repair and SOS response. Notably, hydrogen peroxide- and peracetic acid-treated cells exhibited high mutation rates correlating with the induced SOS response.
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Chia N, Golding I, Goldenfeld N. Lambda-prophage induction modeled as a cooperative failure mode of lytic repression. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:030901. [PMID: 19905052 PMCID: PMC4038166 DOI: 10.1103/physreve.80.030901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Indexed: 05/28/2023]
Abstract
We analyze a system-level model for lytic repression of lambda phage in E. coli using reliability theory, showing that the repressor circuit comprises four redundant components whose failure mode is prophage induction. Our model reflects the specific biochemical mechanisms involved in regulation, including long-range cooperative binding, and its detailed predictions for prophage induction in E. coli under ultraviolet radiation are in good agreement with experimental data.
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Affiliation(s)
- Nicholas Chia
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, USA
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