1
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Pelliciari S, Bodet-Lefèvre S, Fenyk S, Stevens D, Winterhalter C, Schramm FD, Pintar S, Burnham DR, Merces G, Richardson TT, Tashiro Y, Hubbard J, Yardimci H, Ilangovan A, Murray H. The bacterial replication origin BUS promotes nucleobase capture. Nat Commun 2023; 14:8339. [PMID: 38097584 PMCID: PMC10721633 DOI: 10.1038/s41467-023-43823-w] [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: 02/13/2023] [Accepted: 11/21/2023] [Indexed: 12/17/2023] Open
Abstract
Genome duplication is essential for the proliferation of cellular life and this process is generally initiated by dedicated replication proteins at chromosome origins. In bacteria, DNA replication is initiated by the ubiquitous DnaA protein, which assembles into an oligomeric complex at the chromosome origin (oriC) that engages both double-stranded DNA (dsDNA) and single-stranded DNA (ssDNA) to promote DNA duplex opening. However, the mechanism of DnaA specifically opening a replication origin was unknown. Here we show that Bacillus subtilis DnaAATP assembles into a continuous oligomer at the site of DNA melting, extending from a dsDNA anchor to engage a single DNA strand. Within this complex, two nucleobases of each ssDNA binding motif (DnaA-trio) are captured within a dinucleotide binding pocket created by adjacent DnaA proteins. These results provide a molecular basis for DnaA specifically engaging the conserved sequence elements within the bacterial chromosome origin basal unwinding system (BUS).
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Affiliation(s)
- Simone Pelliciari
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Salomé Bodet-Lefèvre
- Centre for Molecular Cell Biology, School of Biological and Behavioural Sciences, Queen Mary University of London, Newark Street, London, E1 2AT, UK
| | - Stepan Fenyk
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Daniel Stevens
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Charles Winterhalter
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Frederic D Schramm
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Sara Pintar
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Daniel R Burnham
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - George Merces
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Tomas T Richardson
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Yumiko Tashiro
- Centre for Molecular Cell Biology, School of Biological and Behavioural Sciences, Queen Mary University of London, Newark Street, London, E1 2AT, UK
| | - Julia Hubbard
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Hasan Yardimci
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Aravindan Ilangovan
- Centre for Molecular Cell Biology, School of Biological and Behavioural Sciences, Queen Mary University of London, Newark Street, London, E1 2AT, UK.
| | - Heath Murray
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK.
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2
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Radford HM, Toft CJ, Sorenson AE, Schaeffer PM. Inhibition of Replication Fork Formation and Progression: Targeting the Replication Initiation and Primosomal Proteins. Int J Mol Sci 2023; 24:ijms24108802. [PMID: 37240152 DOI: 10.3390/ijms24108802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/02/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
Over 1.2 million deaths are attributed to multi-drug-resistant (MDR) bacteria each year. Persistence of MDR bacteria is primarily due to the molecular mechanisms that permit fast replication and rapid evolution. As many pathogens continue to build resistance genes, current antibiotic treatments are being rendered useless and the pool of reliable treatments for many MDR-associated diseases is thus shrinking at an alarming rate. In the development of novel antibiotics, DNA replication is still a largely underexplored target. This review summarises critical literature and synthesises our current understanding of DNA replication initiation in bacteria with a particular focus on the utility and applicability of essential initiation proteins as emerging drug targets. A critical evaluation of the specific methods available to examine and screen the most promising replication initiation proteins is provided.
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Affiliation(s)
- Holly M Radford
- Molecular and Cell Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD 4811, Australia
| | - Casey J Toft
- Molecular and Cell Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD 4811, Australia
| | - Alanna E Sorenson
- Molecular and Cell Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD 4811, Australia
| | - Patrick M Schaeffer
- Molecular and Cell Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD 4811, Australia
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3
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Botto M, Murthy S, Lamers MH. High-Throughput Exonuclease Assay Based on the Fluorescent Base Analogue 2-Aminopurine. ACS OMEGA 2023; 8:8285-8292. [PMID: 36910963 PMCID: PMC9996622 DOI: 10.1021/acsomega.2c06577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
Exonucleases are essential enzymes that remove nucleotides from free DNA ends during DNA replication, DNA repair, and telomere maintenance. Due to their essential role, they are potential targets for novel anticancer and antimicrobial drugs but have so far been little exploited. Here, we present a simple and versatile real-time exonuclease assay based on 2-aminopurine, an intrinsically fluorescent nucleotide that is quenched by neighboring bases when embedded in DNA. We show that our assay is applicable to different eukaryotic and bacterial exonucleases acting on both 3' and 5' DNA ends over a wide range of protein activities and suitable for a high-throughput inhibitor screening campaign. Using our assay, we discover a novel inhibitor of the Mycobacterium tuberculosis PHP-exonuclease that is part of the replicative DNA polymerase DnaE1. Hence, our novel assay will be a useful tool for high-throughput screening for novel exonuclease inhibitors that may interfere with DNA replication or DNA maintenance.
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4
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Winterhalter C, Stevens D, Fenyk S, Pelliciari S, Marchand E, Soultanas P, Ilangovan A, Murray H. SirA inhibits the essential DnaA:DnaD interaction to block helicase recruitment during Bacillus subtilis sporulation. Nucleic Acids Res 2022; 51:4302-4321. [PMID: 36416272 DOI: 10.1093/nar/gkac1060] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 10/04/2022] [Accepted: 10/24/2022] [Indexed: 11/24/2022] Open
Abstract
Bidirectional DNA replication from a chromosome origin requires the asymmetric loading of two helicases, one for each replisome. Our understanding of the molecular mechanisms underpinning helicase loading at bacterial chromosome origins is incomplete. Here we report both positive and negative mechanisms for directing helicase recruitment in the model organism Bacillus subtilis. Systematic characterization of the essential initiation protein DnaD revealed distinct protein interfaces required for homo-oligomerization, interaction with the master initiator protein DnaA, and interaction with the helicase co-loader protein DnaB. Informed by these properties of DnaD, we went on to find that the developmentally expressed repressor of DNA replication initiation, SirA, blocks the interaction between DnaD and DnaA, thereby restricting helicase recruitment from the origin during sporulation to inhibit further initiation events. These results advance our understanding of the mechanisms underpinning DNA replication initiation in B. subtilis, as well as guiding the search for essential cellular activities to target for antimicrobial drug design.
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Affiliation(s)
- Charles Winterhalter
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne NE2 4AX, UK
| | - Daniel Stevens
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne NE2 4AX, UK
| | - Stepan Fenyk
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne NE2 4AX, UK
| | - Simone Pelliciari
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne NE2 4AX, UK
| | - Elie Marchand
- Research Unit in Biology of Microorganisms, Department of Biology, Université de Namur, Namur, Belgium
| | - Panos Soultanas
- Biodiscovery Institute, School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
| | - Aravindan Ilangovan
- Blizard Institute, School of Biological and Behavioural Sciences, Queen Mary University of London, Newark street, London E1 2AT, UK
| | - Heath Murray
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne NE2 4AX, UK
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5
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Chengalroyen MD, Mason MK, Borsellini A, Tassoni R, Abrahams GL, Lynch S, Ahn YM, Ambler J, Young K, Crowley BM, Olsen DB, Warner DF, Barry III CE, Boshoff HIM, Lamers MH, Mizrahi V. DNA-Dependent Binding of Nargenicin to DnaE1 Inhibits Replication in Mycobacterium tuberculosis. ACS Infect Dis 2022; 8:612-625. [PMID: 35143160 PMCID: PMC8922275 DOI: 10.1021/acsinfecdis.1c00643] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Indexed: 12/15/2022]
Abstract
Natural products provide a rich source of potential antimicrobials for treating infectious diseases for which drug resistance has emerged. Foremost among these diseases is tuberculosis. Assessment of the antimycobacterial activity of nargenicin, a natural product that targets the replicative DNA polymerase of Staphylococcus aureus, revealed that it is a bactericidal genotoxin that induces a DNA damage response in Mycobacterium tuberculosis (Mtb) and inhibits growth by blocking the replicative DNA polymerase, DnaE1. Cryo-electron microscopy revealed that binding of nargenicin to Mtb DnaE1 requires the DNA substrate such that nargenicin is wedged between the terminal base pair and the polymerase and occupies the position of both the incoming nucleotide and templating base. Comparative analysis across three bacterial species suggests that the activity of nargenicin is partly attributable to the DNA binding affinity of the replicative polymerase. This work has laid the foundation for target-led drug discovery efforts focused on Mtb DnaE1.
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Affiliation(s)
- Melissa D. Chengalroyen
- SAMRC/NHLS/UCT
Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence
for Biomedical TB Research, Institute of Infectious Disease and Molecular
Medicine and Department of Pathology, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory 7925, South Africa
| | - Mandy K. Mason
- SAMRC/NHLS/UCT
Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence
for Biomedical TB Research, Institute of Infectious Disease and Molecular
Medicine and Department of Pathology, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory 7925, South Africa
| | - Alessandro Borsellini
- Cell
and Chemical Biology, Leiden University
Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
| | - Raffaella Tassoni
- Cell
and Chemical Biology, Leiden University
Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
| | - Garth L. Abrahams
- SAMRC/NHLS/UCT
Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence
for Biomedical TB Research, Institute of Infectious Disease and Molecular
Medicine and Department of Pathology, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory 7925, South Africa
- Tuberculosis
Research Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Disease,
National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United
States
| | - Sasha Lynch
- SAMRC/NHLS/UCT
Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence
for Biomedical TB Research, Institute of Infectious Disease and Molecular
Medicine and Department of Pathology, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory 7925, South Africa
| | - Yong-Mo Ahn
- Tuberculosis
Research Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Disease,
National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United
States
| | - Jon Ambler
- Wellcome
Centre for Infectious Diseases Research in Africa, University of Cape Town, Anzio Road, Observatory 7925, South Africa
| | - Katherine Young
- Infectious
Disease, Merck & Co. Inc., West Point, Pennsylvania 19446, United States
| | - Brendan M. Crowley
- Discovery
Chemistry, Merck & Co. Inc., West Point, Pennsylvania 19446, United States
| | - David B. Olsen
- Infectious
Disease, Merck & Co. Inc., West Point, Pennsylvania 19446, United States
| | - Digby F. Warner
- SAMRC/NHLS/UCT
Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence
for Biomedical TB Research, Institute of Infectious Disease and Molecular
Medicine and Department of Pathology, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory 7925, South Africa
| | - Clifton E. Barry III
- Tuberculosis
Research Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Disease,
National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United
States
| | - Helena I. M. Boshoff
- Tuberculosis
Research Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Disease,
National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United
States
| | - Meindert H. Lamers
- Cell
and Chemical Biology, Leiden University
Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
| | - Valerie Mizrahi
- SAMRC/NHLS/UCT
Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence
for Biomedical TB Research, Institute of Infectious Disease and Molecular
Medicine and Department of Pathology, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory 7925, South Africa
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6
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Convergent evolution in two bacterial replicative helicase loaders. Trends Biochem Sci 2022; 47:620-630. [DOI: 10.1016/j.tibs.2022.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 02/06/2022] [Accepted: 02/08/2022] [Indexed: 12/23/2022]
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7
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Soltan OM, Shoman ME, Abdel-Aziz SA, Narumi A, Konno H, Abdel-Aziz M. Molecular hybrids: A five-year survey on structures of multiple targeted hybrids of protein kinase inhibitors for cancer therapy. Eur J Med Chem 2021; 225:113768. [PMID: 34450497 DOI: 10.1016/j.ejmech.2021.113768] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/23/2021] [Accepted: 08/08/2021] [Indexed: 02/07/2023]
Abstract
Protein kinases have grown over the past few years as a crucial target for different cancer types. With the multifactorial nature of cancer, and the fast development of drug resistance for conventional chemotherapeutics, a strategy for designing multi-target agents was suggested to potentially increase drug efficacy, minimize side effects and retain the proper pharmacokinetic properties. Kinase inhibitors were used extensively in such strategy. Different kinase inhibitor agents which target EGFR, VEGFR, c-Met, CDK, PDK and other targets were merged into hybrids with conventional chemotherapeutics such as tubulin polymerization and topoisomerase inhibitors. Other hybrids were designed gathering kinase inhibitors with targeted cancer therapy such as HDAC, PARP, HSP 90 inhibitors. Nitric oxide donor molecules were also merged with kinase inhibitors for cancer therapy. The current review presents the hybrids designed in the past five years discussing their design principles, results and highlights their future perspectives.
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Affiliation(s)
- Osama M Soltan
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Al-Azhar University, Assiut Branch, Assiut, 71524, Egypt
| | - Mai E Shoman
- Department of Medicinal Chemistry, Faculty of Pharmacy, Minia University, 61519, Minia, Egypt.
| | - Salah A Abdel-Aziz
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Al-Azhar University, Assiut Branch, Assiut, 71524, Egypt; Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Deraya University, 61111, Minia, Egypt
| | - Atsushi Narumi
- Department of Organic Materials Science, Graduate School of Organic Materials Science, Yamagata University, Jonan 4-3-16, Yonezawa, 992-8510, Japan
| | - Hiroyuki Konno
- Department of Biological Engineering, Graduate School of Science and Engineering, Yamagata University, Jonan 4-3-16, Yonezawa, 992-8510, Japan
| | - Mohamed Abdel-Aziz
- Department of Medicinal Chemistry, Faculty of Pharmacy, Minia University, 61519, Minia, Egypt.
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8
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Pelliciari S, Dong MJ, Gao F, Murray H. Evidence for a chromosome origin unwinding system broadly conserved in bacteria. Nucleic Acids Res 2021; 49:7525-7536. [PMID: 34197592 PMCID: PMC8287927 DOI: 10.1093/nar/gkab560] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 06/09/2021] [Accepted: 06/14/2021] [Indexed: 11/12/2022] Open
Abstract
Genome replication is a fundamental requirement for the proliferation of all cells. Throughout the domains of life, conserved DNA replication initiation proteins assemble at specific chromosomal loci termed replication origins and direct loading of replicative helicases (1). Despite decades of study on bacterial replication, the diversity of bacterial chromosome origin architecture has confounded the search for molecular mechanisms directing the initiation process. Recently a basal system for opening a bacterial chromosome origin (oriC) was proposed (2). In the model organism Bacillus subtilis, a pair of double-stranded DNA (dsDNA) binding sites (DnaA-boxes) guide the replication initiator DnaA onto adjacent single-stranded DNA (ssDNA) binding motifs (DnaA-trios) where the protein assembles into an oligomer that stretches DNA to promote origin unwinding. We report here that these core elements are predicted to be present in the majority of bacterial chromosome origins. Moreover, we find that the principle activities of the origin unwinding system are conserved in vitro and in vivo. The results suggest that this basal mechanism for oriC unwinding is broadly functionally conserved and therefore may represent an ancestral system to open bacterial chromosome origins.
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Affiliation(s)
- Simone Pelliciari
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne NE2 4AX, UK
| | - Mei-Jing Dong
- Department of Physics, School of Science, Tianjin University, Tianjin, China.,Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China
| | - Feng Gao
- Department of Physics, School of Science, Tianjin University, Tianjin, China.,Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China
| | - Heath Murray
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne NE2 4AX, UK
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9
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Konikkat S, Scribner MR, Eutsey R, Hiller NL, Cooper VS, McManus J. Quantitative mapping of mRNA 3' ends in Pseudomonas aeruginosa reveals a pervasive role for premature 3' end formation in response to azithromycin. PLoS Genet 2021; 17:e1009634. [PMID: 34252072 PMCID: PMC8297930 DOI: 10.1371/journal.pgen.1009634] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/22/2021] [Accepted: 06/01/2021] [Indexed: 01/06/2023] Open
Abstract
Pseudomonas aeruginosa produces serious chronic infections in hospitalized patients and immunocompromised individuals, including patients with cystic fibrosis. The molecular mechanisms by which P. aeruginosa responds to antibiotics and other stresses to promote persistent infections may provide new avenues for therapeutic intervention. Azithromycin (AZM), an antibiotic frequently used in cystic fibrosis treatment, is thought to improve clinical outcomes through a number of mechanisms including impaired biofilm growth and quorum sensing (QS). The mechanisms underlying the transcriptional response to AZM remain unclear. Here, we interrogated the P. aeruginosa transcriptional response to AZM using a fast, cost-effective genome-wide approach to quantitate RNA 3’ ends (3pMap). We also identified hundreds of P. aeruginosa genes with high incidence of premature 3’ end formation indicative of riboregulation in their transcript leaders using 3pMap. AZM treatment of planktonic and biofilm cultures alters the expression of hundreds of genes, including those involved in QS, biofilm formation, and virulence. Strikingly, most genes downregulated by AZM in biofilms had increased levels of intragenic 3’ ends indicating premature transcription termination, transcriptional pausing, or accumulation of stable intermediates resulting from the action of nucleases. Reciprocally, AZM reduced premature intragenic 3’ end termini in many upregulated genes. Most notably, reduced termination accompanied robust induction of obgE, a GTPase involved in persister formation in P. aeruginosa. Our results support a model in which AZM-induced changes in 3’ end formation alter the expression of central regulators which in turn impairs the expression of QS, biofilm formation and stress response genes, while upregulating genes associated with persistence. Pseudomonas aeruginosa is a common source of hospital-acquired infections and causes prolonged illness in patients with cystic fibrosis. P. aeruginosa infections are often treated with the macrolide antibiotic azithromycin, which changes the expression of many genes involved in infection. By examining such expression changes at nucleotide resolution, we found azithromycin treatment alters the locations of mRNA 3’ ends suggesting most downregulated genes are subject to premature 3’ end formation. We further identified candidate RNA regulatory elements that P. aeruginosa may use to control gene expression. Our work provides new insights in P. aeruginosa gene regulation and its response to antibiotics.
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Affiliation(s)
- Salini Konikkat
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Michelle R. Scribner
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Rory Eutsey
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - N. Luisa Hiller
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Vaughn S. Cooper
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Joel McManus
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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10
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Novel Antibiotics Targeting Bacterial Replicative DNA Polymerases. Antibiotics (Basel) 2020; 9:antibiotics9110776. [PMID: 33158178 PMCID: PMC7694242 DOI: 10.3390/antibiotics9110776] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/31/2020] [Accepted: 11/02/2020] [Indexed: 12/15/2022] Open
Abstract
Multidrug resistance is a worldwide problem that is an increasing threat to global health. Therefore, the development of new antibiotics that inhibit novel targets is of great urgency. Some of the most successful antibiotics inhibit RNA transcription, RNA translation, and DNA replication. Transcription and translation are inhibited by directly targeting the RNA polymerase or ribosome, respectively. DNA replication, in contrast, is inhibited indirectly through targeting of DNA gyrases, and there are currently no antibiotics that inhibit DNA replication by directly targeting the replisome. This contrasts with antiviral therapies where the viral replicases are extensively targeted. In the last two decades there has been a steady increase in the number of compounds that target the bacterial replisome. In particular a variety of inhibitors of the bacterial replicative polymerases PolC and DnaE have been described, with one of the DNA polymerase inhibitors entering clinical trials for the first time. In this review we will discuss past and current work on inhibition of DNA replication, and the potential of bacterial DNA polymerase inhibitors in particular as attractive targets for a new generation of antibiotics.
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11
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Konto-Ghiorghi Y, Norris V. Hypothesis: nucleoid-associated proteins segregate with a parental DNA strand to generate coherent phenotypic diversity. Theory Biosci 2020; 140:17-25. [PMID: 33095418 DOI: 10.1007/s12064-020-00323-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 10/12/2020] [Indexed: 01/07/2023]
Abstract
The generation of a phenotypic diversity that is coherent across a bacterial population is a fundamental problem. We propose here that the DNA strand-specific segregation of certain nucleoid-associated proteins or NAPs results in these proteins being asymmetrically distributed to the daughter cells. We invoke a variety of mechanisms as responsible for this asymmetrical segregation including those based on differences between the leading and lagging strands, post-translational modifications, oligomerisation and association with membrane domains.
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Affiliation(s)
- Yoan Konto-Ghiorghi
- Laboratory of Microbiology Signals and Microenvironment, EA 4312, University of Rouen, 76821, Mont Saint Aignan, France
| | - Vic Norris
- Laboratory of Microbiology Signals and Microenvironment, EA 4312, University of Rouen, 76821, Mont Saint Aignan, France.
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12
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Blocking the Trigger: Inhibition of the Initiation of Bacterial Chromosome Replication as an Antimicrobial Strategy. Antibiotics (Basel) 2019; 8:antibiotics8030111. [PMID: 31390740 PMCID: PMC6784150 DOI: 10.3390/antibiotics8030111] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/02/2019] [Accepted: 08/04/2019] [Indexed: 12/19/2022] Open
Abstract
All bacterial cells must duplicate their genomes prior to dividing into two identical daughter cells. Chromosome replication is triggered when a nucleoprotein complex, termed the orisome, assembles, unwinds the duplex DNA, and recruits the proteins required to establish new replication forks. Obviously, the initiation of chromosome replication is essential to bacterial reproduction, but this process is not inhibited by any of the currently-used antimicrobial agents. Given the urgent need for new antibiotics to combat drug-resistant bacteria, it is logical to evaluate whether or not unexploited bacterial processes, such as orisome assembly, should be more closely examined for sources of novel drug targets. This review will summarize current knowledge about the proteins required for bacterial chromosome initiation, as well as how orisomes assemble and are regulated. Based upon this information, we discuss current efforts and potential strategies and challenges for inhibiting this initiation pharmacologically.
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13
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Stimulation of Replication Template-Switching by DNA-Protein Crosslinks. Genes (Basel) 2018; 10:genes10010014. [PMID: 30591691 PMCID: PMC6357072 DOI: 10.3390/genes10010014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/10/2018] [Accepted: 12/12/2018] [Indexed: 11/16/2022] Open
Abstract
Covalent DNA protein crosslinks (DPCs) are common lesions that block replication. We examine here the consequence of DPCs on mutagenesis involving replicational template-switch reactions in Escherichia coli. 5-Azacytidine (5-azaC) is a potent mutagen for template-switching. This effect is dependent on DNA cytosine methylase (Dcm), implicating the Dcm-DNA covalent complex trapped by 5-azaC as the initiator for mutagenesis. The leading strand of replication is more mutable than the lagging strand, which can be explained by blocks to the replicative helicase and/or fork regression. We find that template-switch mutagenesis induced by 5-azaC does not require double strand break repair via RecABCD; the ability to induce the SOS response is anti-mutagenic. Mutants in recB, but not recA, exhibit high constitutive rates of template-switching, and we suggest that RecBCD-mediated DNA degradation prevents template-switching associated with fork regression. A mutation in the DnaB fork helicase also promotes high levels of template-switching. We also find that other DPC-inducers, formaldehyde (a non-specific crosslinker) and ciprofloxacin (a topoisomerase II poison) are also strong mutagens for template-switching with similar genetic properties. Induction of mutations and genetic rearrangements that occur by template-switching may constitute a previously unrecognized component of the genotoxicity and genetic instability promoted by DPCs.
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14
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McGrath AE, Martyn AP, Whittell LR, Dawes FE, Beck JL, Dixon NE, Kelso MJ, Oakley AJ. Crystal structures and biochemical characterization of DNA sliding clamps from three Gram-negative bacterial pathogens. J Struct Biol 2018; 204:396-405. [DOI: 10.1016/j.jsb.2018.10.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/20/2018] [Accepted: 10/22/2018] [Indexed: 12/19/2022]
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15
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Trojanowski D, Hołówka J, Zakrzewska-Czerwińska J. Where and When Bacterial Chromosome Replication Starts: A Single Cell Perspective. Front Microbiol 2018; 9:2819. [PMID: 30534115 PMCID: PMC6275241 DOI: 10.3389/fmicb.2018.02819] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 11/02/2018] [Indexed: 12/18/2022] Open
Abstract
Bacterial chromosomes have a single, unique replication origin (named oriC), from which DNA synthesis starts. This study describes methods of visualizing oriC regions and the chromosome replication in single living bacterial cells in real-time. This review also discusses the impact of live cell imaging techniques on understanding of chromosome replication dynamics, particularly at the initiation step, in different species of bacteria.
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Affiliation(s)
- Damian Trojanowski
- Department of Molecular Microbiology, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Joanna Hołówka
- Department of Molecular Microbiology, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
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16
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Ilic S, Cohen S, Singh M, Tam B, Dayan A, Akabayov B. DnaG Primase-A Target for the Development of Novel Antibacterial Agents. Antibiotics (Basel) 2018; 7:E72. [PMID: 30104489 PMCID: PMC6163395 DOI: 10.3390/antibiotics7030072] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/06/2018] [Accepted: 08/09/2018] [Indexed: 12/21/2022] Open
Abstract
The bacterial primase-an essential component in the replisome-is a promising but underexploited target for novel antibiotic drugs. Bacterial primases have a markedly different structure than the human primase. Inhibition of primase activity is expected to selectively halt bacterial DNA replication. Evidence is growing that halting DNA replication has a bacteriocidal effect. Therefore, inhibitors of DNA primase could provide antibiotic agents. Compounds that inhibit bacterial DnaG primase have been developed using different approaches. In this paper, we provide an overview of the current literature on DNA primases as novel drug targets and the methods used to find their inhibitors. Although few inhibitors have been identified, there are still challenges to develop inhibitors that can efficiently halt DNA replication and may be applied in a clinical setting.
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Affiliation(s)
- Stefan Ilic
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
| | - Shira Cohen
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
| | - Meenakshi Singh
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
| | - Benjamin Tam
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
| | - Adi Dayan
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
| | - Barak Akabayov
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
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