1
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Storozhuk O, Bruekner SR, Paul A, Lebbink JHG, Sixma TK, Friedhoff P. MutL Activates UvrD by Interaction Between the MutL C-terminal Domain and the UvrD 2B Domain. J Mol Biol 2024; 436:168589. [PMID: 38677494 DOI: 10.1016/j.jmb.2024.168589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 04/14/2024] [Accepted: 04/19/2024] [Indexed: 04/29/2024]
Abstract
UvrD is a helicase vital for DNA replication and quality control processes. In its monomeric state, UvrD exhibits limited helicase activity, necessitating either dimerization or assistance from an accessory protein to efficiently unwind DNA. Within the DNA mismatch repair pathway, MutL plays a pivotal role in relaying the repair signal, enabling UvrD to unwind DNA from the strand incision site up to and beyond the mismatch. Although this interdependence is well-established, the precise mechanism of activation and the specific MutL-UvrD interactions that trigger helicase activity remain elusive. To address these questions, we employed site-specific crosslinking techniques using single-cysteine variants of MutL and UvrD followed by functional assays. Our investigation unveils that the C-terminal domain of MutL not only engages with UvrD but also acts as a self-sufficient activator of UvrD helicase activity on DNA substrates with 3'-single-stranded tails. Especially when MutL is covalently attached to the 2B or 1B domain the tail length can be reduced to a minimal substrate of 5 nucleotides without affecting unwinding efficiency.
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Affiliation(s)
- Olha Storozhuk
- Institute for Biochemistry, FB 08, Justus Liebig University, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
| | - Susanne R Bruekner
- Division of Biochemistry, Netherlands Cancer Institute and Oncode Institute, Amsterdam, the Netherlands
| | - Ankon Paul
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Joyce H G Lebbink
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Radiotherapy, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Titia K Sixma
- Division of Biochemistry, Netherlands Cancer Institute and Oncode Institute, Amsterdam, the Netherlands
| | - Peter Friedhoff
- Institute for Biochemistry, FB 08, Justus Liebig University, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany.
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2
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Browning KR, Merrikh H. Pathogenic bacteria experience pervasive RNA polymerase backtracking during infection. mBio 2024; 15:e0273723. [PMID: 38095872 PMCID: PMC10790778 DOI: 10.1128/mbio.02737-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/06/2023] [Indexed: 12/26/2023] Open
Abstract
IMPORTANCE Eukaryotic hosts have defense mechanisms that may disrupt molecular transactions along the pathogen's chromosome through excessive DNA damage. Given that DNA damage stalls RNA polymerase (RNAP) thereby increasing mutagenesis, investigating how host defense mechanisms impact the movement of the transcription machinery on the pathogen chromosome is crucial. Using a new methodology we developed, we elucidated the dynamics of RNAP movement and association with the chromosome in the pathogenic bacterium Salmonella enterica during infection. We found that dynamics of RNAP movement on the chromosome change significantly during infection genome-wide, including at regions that encode for key virulence genes. In particular, we found that there is pervasive RNAP backtracking on the bacterial chromosome during infections and that anti-backtracking factors are critical for pathogenesis. Altogether, our results suggest that, interestingly, the host environment can promote the development of antimicrobial resistance and hypervirulence as stalled RNAPs can accelerate evolution through increased mutagenesis.
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Affiliation(s)
- Kaitlyn R. Browning
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Houra Merrikh
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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3
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Chadda A, Kozlov AG, Nguyen B, Lohman TM, Galburt EA. Mycobacterium tuberculosis Ku Stimulates Multi-round DNA Unwinding by UvrD1 Monomers. J Mol Biol 2024; 436:168367. [PMID: 37972687 PMCID: PMC10836237 DOI: 10.1016/j.jmb.2023.168367] [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: 09/28/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 11/19/2023]
Abstract
Mycobacterium tuberculosis is the causative agent of Tuberculosis. During the host response to infection, the bacterium is exposed to both reactive oxygen species and nitrogen intermediates that can cause DNA damage. It is becoming clear that the DNA damage response in Mtb and related actinobacteria function via distinct pathways as compared to well-studied model bacteria. For example, we have previously shown that the DNA repair helicase UvrD1 is activated for processive unwinding via redox-dependent dimerization. In addition, mycobacteria contain a homo-dimeric Ku protein, homologous to the eukaryotic Ku70/Ku80 dimer, that plays roles in double-stranded break repair via non-homologous end-joining. Kuhas been shown to stimulate the helicase activity of UvrD1, but the molecular mechanism, as well as which redox form of UvrD1 is activated, is unknown. We show here that Ku specifically stimulates multi-round unwinding by UvrD1 monomers which are able to slowly unwind DNA, but at rates 100-fold slower than the dimer. We also demonstrate that the UvrD1 C-terminal Tudor domain is required for the formation of a Ku-UvrD1 protein complex and activation. We show that Mtb Ku dimers bind with high nearest neighbor cooperativity to duplex DNA and that UvrD1 activation is observed when the DNA substrate is bound with two or three Ku dimers. Our observations reveal aspects of the interactions between DNA, Mtb Ku, and UvrD1 and highlight the potential role of UvrD1 in multiple DNA repair pathways through different mechanisms of activation.
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Affiliation(s)
- Ankita Chadda
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Alexander G Kozlov
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Binh Nguyen
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Timothy M Lohman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Eric A Galburt
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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4
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Wollman AJM, Syeda AH, Howard JAL, Payne-Dwyer A, Leech A, Warecka D, Guy C, McGlynn P, Hawkins M, Leake MC. Tetrameric UvrD Helicase Is Located at the E. Coli Replisome due to Frequent Replication Blocks. J Mol Biol 2024; 436:168369. [PMID: 37977299 DOI: 10.1016/j.jmb.2023.168369] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 11/10/2023] [Accepted: 11/11/2023] [Indexed: 11/19/2023]
Abstract
DNA replication in all organisms must overcome nucleoprotein blocks to complete genome duplication. Accessory replicative helicases in Escherichia coli, Rep and UvrD, help remove these blocks and aid the re-initiation of replication. Mechanistic details of Rep function have emerged from recent live cell studies; however, the division of UvrD functions between its activities in DNA repair and role as an accessory helicase remain unclear in live cells. By integrating super-resolved single-molecule fluorescence microscopy with biochemical analysis, we find that UvrD self-associates into tetrameric assemblies and, unlike Rep, is not recruited to a specific replisome protein despite being found at approximately 80% of replication forks. Instead, its colocation with forks is likely due to the very high frequency of replication blocks composed of DNA-bound proteins, including RNA polymerase and factors involved in repairing DNA damage. Deleting rep and DNA repair factor genes mutS and uvrA, and inhibiting transcription through RNA polymerase mutation and antibiotic inhibition, indicates that the level of UvrD at the fork is dependent on UvrD's function. Our findings show that UvrD is recruited to sites of nucleoprotein blocks via different mechanisms to Rep and plays a multi-faceted role in ensuring successful DNA replication.
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Affiliation(s)
- Adam J M Wollman
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Aisha H Syeda
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Jamieson A L Howard
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Alex Payne-Dwyer
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Andrew Leech
- Bioscience Technology Facility, Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Dominika Warecka
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Colin Guy
- Covance Laboratories Ltd., Otley Road, Harrogate HG3 1PY, United Kingdom
| | - Peter McGlynn
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Michelle Hawkins
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Mark C Leake
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom.
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5
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Browning KR, Merrikh H. Pathogenic bacteria experience pervasive RNA polymerase backtracking during infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.12.540596. [PMID: 37215019 PMCID: PMC10197661 DOI: 10.1101/2023.05.12.540596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Pathogenic bacteria and their eukaryotic hosts are in a constant arms race. Hosts have numerous defense mechanisms at their disposal that not only challenge the bacterial invaders, but have the potential to disrupt molecular transactions along the bacterial chromosome. However, it is unclear how the host impacts association of proteins with the bacterial chromosome at the molecular level during infection. This is partially due to the lack of a method that could detect these events in pathogens while they are within host cells. We developed and optimized a system capable of mapping and measuring levels of bacterial proteins associated with the chromosome while they are actively infecting the host (referred to as PIC-seq). Here, we focused on the dynamics of RNA polymerase (RNAP) movement and association with the chromosome in the pathogenic bacterium Salmonella enterica as a model system during infection. Using PIC-seq, we found that RNAP association patterns with the chromosome change during infection genome-wide, including at regions that encode for key virulence genes. Importantly, we found that infection of a host significantly increases RNAP backtracking on the bacterial chromosome. RNAP backtracking is the most common form of disruption to RNAP progress on the chromosome. Interestingly, we found that the resolution of backtracked RNAPs via the anti-backtracking factors GreA and GreB is critical for pathogenesis, revealing a new class of virulence genes. Altogether, our results strongly suggest that infection of a host significantly impacts transcription by disrupting RNAP movement on the chromosome within the bacterial pathogen. The increased backtracking events have important implications not only for efficient transcription, but also for mutation rates as stalled RNAPs increase the levels of mutagenesis.
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Affiliation(s)
- Kaitlyn R. Browning
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN 37232, USA
| | - Houra Merrikh
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN 37232, USA
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6
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Kapoor I, Shaw A, Naha A, Emam EAF, Varshney U. Role of the nucleotide excision repair pathway proteins (UvrB and UvrD2) in recycling UdgB, a base excision repair enzyme in Mycobacterium smegmatis. DNA Repair (Amst) 2022; 113:103316. [PMID: 35306347 DOI: 10.1016/j.dnarep.2022.103316] [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: 10/19/2021] [Revised: 01/30/2022] [Accepted: 03/02/2022] [Indexed: 11/24/2022]
Abstract
Cross-talks between DNA repair pathways are emerging as a crucial strategy in the maintenance of the genomic integrity. A double-stranded (ds) DNA specific DNA glycosylase, UdgB is known to excise uracil, hypoxanthine and ethenocytosine. We earlier showed that Mycobacterium smegmatis (Msm) UdgB stays back on the AP-sites it generates in the DNA upon excision of the damaged bases. Here, we show that in an Msm strain deleted for a nucleotide excision repair (NER) protein, UvrB (uvrB-), UdgB expression is toxic, and its deletion from the genome (udgB-) rescues the strain from the genotoxic stress. However, UdgB bound AP-site is not a direct substrate for NER in vitro. We show that UvrD2 and UvrB, known helicases with single-stranded (ss) DNA translocase activity, facilitate recycling of UdgB from AP-DNA. Our studies reveal that the helicases play an important role in exposing the AP-sites in DNA and make them available for further repair.
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Affiliation(s)
- Indu Kapoor
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Abhirup Shaw
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Arindam Naha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Elhassan Ali Fathi Emam
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Umesh Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.
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7
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Jain M, Golzarroshan B, Lin CL, Agrawal S, Tang WH, Wu CJ, Yuan HS. Dimeric assembly of human Suv3 helicase promotes its RNA unwinding function in mitochondrial RNA degradosome for RNA decay. Protein Sci 2022; 31:e4312. [PMID: 35481630 PMCID: PMC9044407 DOI: 10.1002/pro.4312] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/21/2022] [Accepted: 04/01/2022] [Indexed: 11/12/2022]
Abstract
Human Suv3 is a unique homodimeric helicase that constitutes the major component of the mitochondrial degradosome to work cooperatively with exoribonuclease PNPase for efficient RNA decay. However, the molecular mechanism of how Suv3 is assembled into a homodimer to unwind RNA remains elusive. Here, we show that dimeric Suv3 preferentially binds to and unwinds DNA-DNA, DNA-RNA, and RNA-RNA duplexes with a long 3' overhang (≥10 nucleotides). The C-terminal tail (CTT)-truncated Suv3 (Suv3ΔC) becomes a monomeric protein that binds to and unwinds duplex substrates with ~six to sevenfold lower activities relative to dimeric Suv3. Only dimeric Suv3, but not monomeric Suv3ΔC, binds RNA independently of ATP or ADP, and is capable of interacting with PNPase, indicating that dimeric Suv3 assembly ensures its continuous association with RNA and PNPase during ATP hydrolysis cycles for efficient RNA degradation. We further determined the crystal structure of the apo-form of Suv3ΔC, and SAXS structures of dimeric Suv3 and PNPase-Suv3 complex, showing that dimeric Suv3 caps on the top of PNPase via interactions with S1 domains, and forms a dumbbell-shaped degradosome complex with PNPase. Overall, this study reveals that Suv3 is assembled into a dimeric helicase by its CTT for efficient and persistent RNA binding and unwinding to facilitate interactions with PNPase, promote RNA degradation, and maintain mitochondrial genome integrity and homeostasis.
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Affiliation(s)
- Monika Jain
- Molecular and Cell Biology, Taiwan International Graduate Program, Academia Sinica and Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.,Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | | | - Chia-Liang Lin
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Sashank Agrawal
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Wei-Hsuan Tang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.,Graduate Institute of Biochemistry and Molecular Biology, National Taiwan University, Taipei, Taiwan
| | - Chiu-Ju Wu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.,Graduate Institute of Biochemistry and Molecular Biology, National Taiwan University, Taipei, Taiwan
| | - Hanna S Yuan
- Molecular and Cell Biology, Taiwan International Graduate Program, Academia Sinica and Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.,Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.,Graduate Institute of Biochemistry and Molecular Biology, National Taiwan University, Taipei, Taiwan
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8
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Mycobacterium tuberculosis DNA repair helicase UvrD1 is activated by redox-dependent dimerization via a 2B domain cysteine. Proc Natl Acad Sci U S A 2022; 119:2114501119. [PMID: 35173050 PMCID: PMC8872793 DOI: 10.1073/pnas.2114501119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/31/2021] [Indexed: 01/13/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) causes tuberculosis and, during infection, is exposed to reactive oxygen species and reactive nitrogen intermediates from the host immune response that can cause DNA damage. UvrD-like proteins are involved in DNA repair and replication and belong to the SF1 family of DNA helicases that use ATP hydrolysis to catalyze DNA unwinding. In Mtb, there are two UvrD-like enzymes, where UvrD1 is most closely related to other family members. Previous studies have suggested that UvrD1 is exclusively monomeric; however, it is well known that Escherichia coli UvrD and other UvrD family members exhibit monomer-dimer equilibria and unwind as dimers in the absence of accessory factors. Here, we reconcile these incongruent studies by showing that Mtb UvrD1 exists in monomer, dimer, and higher-order oligomeric forms, where dimerization is regulated by redox potential. We identify a 2B domain cysteine, conserved in many Actinobacteria, that underlies this effect. We also show that UvrD1 DNA-unwinding activity correlates specifically with the dimer population and is thus titrated directly via increasing positive (i.e., oxidative) redox potential. Consistent with the regulatory role of the 2B domain and the dimerization-based activation of DNA unwinding in UvrD family helicases, these results suggest that UvrD1 is activated under oxidizing conditions when it may be needed to respond to DNA damage during infection.
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9
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The Facts and Family Secrets of Plasmids That Replicate via the Rolling-Circle Mechanism. Microbiol Mol Biol Rev 2021; 86:e0022220. [PMID: 34878299 DOI: 10.1128/mmbr.00222-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Plasmids are self-replicative DNA elements that are transferred between bacteria. Plasmids encode not only antibiotic resistance genes but also adaptive genes that allow their hosts to colonize new niches. Plasmid transfer is achieved by conjugation (or mobilization), phage-mediated transduction, and natural transformation. Thousands of plasmids use the rolling-circle mechanism for their propagation (RCR plasmids). They are ubiquitous, have a high copy number, exhibit a broad host range, and often can be mobilized among bacterial species. Based upon the replicon, RCR plasmids have been grouped into several families, the best known of them being pC194 and pUB110 (Rep_1 family), pMV158 and pE194 (Rep_2 family), and pT181 and pC221 (Rep_trans family). Genetic traits of RCR plasmids are analyzed concerning (i) replication mediated by a DNA-relaxing initiator protein and its interactions with the cognate DNA origin, (ii) lagging-strand origins of replication, (iii) antibiotic resistance genes, (iv) mobilization functions, (v) replication control, performed by proteins and/or antisense RNAs, and (vi) the participating host-encoded functions. The mobilization functions include a relaxase initiator of transfer (Mob), an origin of transfer, and one or two small auxiliary proteins. There is a family of relaxases, the MOBV family represented by plasmid pMV158, which has been revisited and updated. Family secrets, like a putative open reading frame of unknown function, are reported. We conclude that basic research on RCR plasmids is of importance, and our perspectives contemplate the concept of One Earth because we should incorporate bacteria into our daily life by diminishing their virulence and, at the same time, respecting their genetic diversity.
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10
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Wiedermannová J, Krásný L. β-CASP proteins removing RNA polymerase from DNA: when a torpedo is needed to shoot a sitting duck. Nucleic Acids Res 2021; 49:10221-10234. [PMID: 34551438 PMCID: PMC8501993 DOI: 10.1093/nar/gkab803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/01/2021] [Accepted: 09/06/2021] [Indexed: 12/12/2022] Open
Abstract
During the first step of gene expression, RNA polymerase (RNAP) engages DNA to transcribe RNA, forming highly stable complexes. These complexes need to be dissociated at the end of transcription units or when RNAP stalls during elongation and becomes an obstacle (‘sitting duck’) to further transcription or replication. In this review, we first outline the mechanisms involved in these processes. Then, we explore in detail the torpedo mechanism whereby a 5′–3′ RNA exonuclease (torpedo) latches itself onto the 5′ end of RNA protruding from RNAP, degrades it and upon contact with RNAP, induces dissociation of the complex. This mechanism, originally described in Eukaryotes and executed by Xrn-type 5′–3′ exonucleases, was recently found in Bacteria and Archaea, mediated by β-CASP family exonucleases. We discuss the mechanistic aspects of this process across the three kingdoms of life and conclude that 5′–3′ exoribonucleases (β-CASP and Xrn families) involved in the ancient torpedo mechanism have emerged at least twice during evolution.
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Affiliation(s)
- Jana Wiedermannová
- Correspondence may also be addressed to Jana Wiedermannová. Tel: +44 191 208 3226; Fax: +44 191 208 3205;
| | - Libor Krásný
- To whom correspondence should be addressed. Tel: +420 241063208;
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11
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Brüning JG, Marians KJ. Bypass of complex co-directional replication-transcription collisions by replisome skipping. Nucleic Acids Res 2021; 49:9870-9885. [PMID: 34469567 PMCID: PMC8464059 DOI: 10.1093/nar/gkab760] [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: 06/23/2021] [Revised: 08/17/2021] [Accepted: 08/24/2021] [Indexed: 12/27/2022] Open
Abstract
Collisions between the replisome and RNA polymerases [RNAP(s)] are the main obstacle to DNA replication. These collisions can occur either head-on or co-directionally with respect to the direction of translocation of both complexes. Whereas head-on collisions require additional factors to be resolved, co-directional collisions are thought to be overcome by the replisome itself using the mRNA transcript as a primer. We show that mRNA takeover is utilized primarily after collisions with single RNAP complexes with short transcripts. Bypass of more complex transcription complexes requires the synthesis of a new primer downstream of the RNAP for the replisome to resume leading-strand synthesis. In both cases, bypass proceeds with displacement of the RNAP. Rep, Mfd, UvrD and RNase H can process the RNAP block and facilitate replisome bypass by promoting the formation of continuous leading strands. Bypass of co-directional RNAP(s) and/or R-loops is determined largely by the length of the obstacle that the replisome needs to traverse: R-loops are about equally as potent obstacles as RNAP arrays if they occupy the same length of the DNA template.
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Affiliation(s)
- Jan-Gert Brüning
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Kenneth J Marians
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
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12
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Abstract
The low G + C Gram-positive bacteria represent some of the most medically and industrially important microorganisms. They are relied on for the production of food and dietary supplements, enzymes and antibiotics, as well as being responsible for the majority of nosocomial infections and serving as a reservoir for antibiotic resistance. Control of gene expression in this group is more highly studied than in any bacteria other than the Gram-negative model Escherichia coli, yet until recently no structural information on RNA polymerase (RNAP) from this group was available. This review will summarize recent reports on the high-resolution structure of RNAP from the model low G + C representative Bacillus subtilis, including the role of auxiliary subunits δ and ε, and outline approaches for the development of antimicrobials to target RNAP from this group.
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Affiliation(s)
- Michael Miller
- School Of Environmental And Life Sciences, University Of Newcastle, Callaghan, NSW, Australia
| | - Aaron J Oakley
- School Of Environmental And Life Sciences, University Of Newcastle, Callaghan, NSW, Australia
| | - Peter J Lewis
- School Of Environmental And Life Sciences, University Of Newcastle, Callaghan, NSW, Australia.,School Of Chemistry And Molecular Bioscience, University Of Wollongong And Illawarra Health And Medical Research Institute, Wollongong, Nsw, Australia
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13
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Urrutia-Irazabal I, Ault JR, Sobott F, Savery NJ, Dillingham MS. Analysis of the PcrA-RNA polymerase complex reveals a helicase interaction motif and a role for PcrA/UvrD helicase in the suppression of R-loops. eLife 2021; 10:68829. [PMID: 34279225 PMCID: PMC8318588 DOI: 10.7554/elife.68829] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/16/2021] [Indexed: 12/12/2022] Open
Abstract
The PcrA/UvrD helicase binds directly to RNA polymerase (RNAP) but the structural basis for this interaction and its functional significance have remained unclear. In this work, we used biochemical assays and hydrogen-deuterium exchange coupled to mass spectrometry to study the PcrA-RNAP complex. We find that PcrA binds tightly to a transcription elongation complex in a manner dependent on protein:protein interaction with the conserved PcrA C-terminal Tudor domain. The helicase binds predominantly to two positions on the surface of RNAP. The PcrA C-terminal domain engages a conserved region in a lineage-specific insert within the β subunit which we identify as a helicase interaction motif present in many other PcrA partner proteins, including the nucleotide excision repair factor UvrB. The catalytic core of the helicase binds near the RNA and DNA exit channels and blocking PcrA activity in vivo leads to the accumulation of R-loops. We propose a role for PcrA as an R-loop suppression factor that helps to minimize conflicts between transcription and other processes on DNA including replication.
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Affiliation(s)
- Inigo Urrutia-Irazabal
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol. Biomedical Sciences Building, University Walk, Bristol, United Kingdom
| | - James R Ault
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Frank Sobott
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Nigel J Savery
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol. Biomedical Sciences Building, University Walk, Bristol, United Kingdom
| | - Mark S Dillingham
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol. Biomedical Sciences Building, University Walk, Bristol, United Kingdom
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14
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Nguyen B, Shinn MK, Weiland E, Lohman TM. Regulation of E. coli Rep helicase activity by PriC. J Mol Biol 2021; 433:167072. [PMID: 34081984 DOI: 10.1016/j.jmb.2021.167072] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/11/2021] [Accepted: 05/20/2021] [Indexed: 11/28/2022]
Abstract
Stalled DNA replication forks can result in incompletely replicated genomes and cell death. DNA replication restart pathways have evolved to deal with repair of stalled forks and E. coli Rep helicase functions in this capacity. Rep and an accessory protein, PriC, assemble at a stalled replication fork to facilitate loading of other replication proteins. A Rep monomer is a rapid and processive single stranded (ss) DNA translocase but needs to be activated to function as a helicase. Activation of Rep in vitro requires self-assembly to form a dimer, removal of its auto-inhibitory 2B sub-domain, or interactions with an accessory protein. Rep helicase activity has been shown to be stimulated by PriC, although the mechanism of activation is not clear. Using stopped flow kinetics, analytical sedimentation and single molecule fluorescence methods, we show that a PriC dimer activates the Rep monomer helicase and can also stimulate the Rep dimer helicase. We show that PriC can self-assemble to form dimers and tetramers and that Rep and PriC interact in the absence of DNA. We further show that PriC serves as a Rep processivity factor, presumably co-translocating with Rep during DNA unwinding. Activation is specific for Rep since PriC does not activate the UvrD helicase. Interaction of PriC with the C-terminal acidic tip of the ssDNA binding protein, SSB, eliminates Rep activation by stabilizing the PriC monomer. This suggests a likely mechanism for Rep activation by PriC at a stalled replication fork.
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Affiliation(s)
- Binh Nguyen
- Department of Biochemistry and Molecular Biophysics, Box 8231, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, United States
| | - Min Kyung Shinn
- Department of Physics, Washington University in St. Louis, St. Louis, MO 63130, United States
| | - Elizabeth Weiland
- Department of Biochemistry and Molecular Biophysics, Box 8231, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, United States
| | - Timothy M Lohman
- Department of Biochemistry and Molecular Biophysics, Box 8231, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, United States.
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15
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Brüning JG, Marians KJ. Replisome bypass of transcription complexes and R-loops. Nucleic Acids Res 2020; 48:10353-10367. [PMID: 32926139 PMCID: PMC7544221 DOI: 10.1093/nar/gkaa741] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/22/2020] [Accepted: 08/25/2020] [Indexed: 12/16/2022] Open
Abstract
The vast majority of the genome is transcribed by RNA polymerases. G+C-rich regions of the chromosomes and negative superhelicity can promote the invasion of the DNA by RNA to form R-loops, which have been shown to block DNA replication and promote genome instability. However, it is unclear whether the R-loops themselves are sufficient to cause this instability or if additional factors are required. We have investigated replisome collisions with transcription complexes and R-loops using a reconstituted bacterial DNA replication system. RNA polymerase transcription complexes co-directionally oriented with the replication fork were transient blockages, whereas those oriented head-on were severe, stable blockages. On the other hand, replisomes easily bypassed R-loops on either template strand. Replication encounters with R-loops on the leading-strand template (co-directional) resulted in gaps in the nascent leading strand, whereas lagging-strand template R-loops (head-on) had little impact on replication fork progression. We conclude that whereas R-loops alone can act as transient replication blocks, most genome-destabilizing replication fork stalling likely occurs because of proteins bound to the R-loops.
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Affiliation(s)
- Jan-Gert Brüning
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Kenneth J Marians
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
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16
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Kawale AA, Burmann BM. UvrD helicase-RNA polymerase interactions are governed by UvrD's carboxy-terminal Tudor domain. Commun Biol 2020; 3:607. [PMID: 33097771 PMCID: PMC7585439 DOI: 10.1038/s42003-020-01332-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 09/28/2020] [Indexed: 12/12/2022] Open
Abstract
All living organisms have to cope with the constant threat of genome damage by UV light and other toxic reagents. To maintain the integrity of their genomes, organisms developed a variety of DNA repair pathways. One of these, the Transcription Coupled DNA-Repair (TCR) pathway, is triggered by stalled RNA Polymerase (RNAP) complexes at DNA damage sites on actively transcribed genes. A recently elucidated bacterial TCR pathway employs the UvrD helicase pulling back stalled RNAP complexes from the damage, stimulating recruitment of the DNA-repair machinery. However, structural and functional aspects of UvrD's interaction with RNA Polymerase remain elusive. Here we used advanced solution NMR spectroscopy to investigate UvrD's role within the TCR, identifying that the carboxy-terminal region of the UvrD helicase facilitates RNAP interactions by adopting a Tudor-domain like fold. Subsequently, we functionally analyzed this domain, identifying it as a crucial component for the UvrD-RNAP interaction besides having nucleic-acid affinity.
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Affiliation(s)
- Ashish A Kawale
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, 40530, Sweden
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, 40530, Sweden
| | - Björn M Burmann
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, 40530, Sweden.
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, 40530, Sweden.
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17
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Bernardes JS, Eberle RJ, Vieira FRJ, Coronado MA. A comparative pan-genomic analysis of 53 C. pseudotuberculosis strains based on functional domains. J Biomol Struct Dyn 2020; 39:6974-6986. [PMID: 32779519 DOI: 10.1080/07391102.2020.1805017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Corynebacterium pseudotuberculosis is a pathogenic bacterium with great veterinary and economic importance. It is classified into two biovars: ovis, nitrate-negative, that causes lymphadenitis in small ruminants and equi, nitrate-positive, causing ulcerative lymphangitis in equines. With the explosive growth of available genomes of several strains, pan-genome analysis has opened new opportunities for understanding the dynamics and evolution of C. pseudotuberculosis. However, few pan-genomic studies have compared biovars equi and ovis. Such studies have considered a reduced number of strains and compared entire genomes. Here we conducted an original pan-genome analysis based on protein sequences and their functional domains. We considered 53 C. pseudotuberculosis strains from both biovars isolated from different hosts and countries. We have analysed conserved domains, common domains more frequently found in each biovar and biovar-specific (unique) domains. Our results demonstrated that biovar equi is more variable; there is a significant difference in the number of proteins per strains, probably indicating the occurrence of more gene loss/gain events. Moreover, strains of biovar equi presented a higher number of biovar-specific domains, 77 against only eight in biovar ovis, most of them are associated with virulence mechanisms. With this domain analysis, we have identified functional differences among strains of biovars ovis and equi that could be related to niche-adaptation and probably help to better understanding mechanisms of virulence and pathogenesis. The distribution patterns of functional domains identified in this work might have impacts on bacterial physiology and lifestyle, encouraging the development of new diagnoses, vaccines, and treatments for C. pseudotuberculosis diseases.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Juliana S Bernardes
- Laboratoire de Biologie Computationelle et Quantitative, UMR 7238, CNRS, Sorbonne Université, Paris, France
| | - Raphael J Eberle
- Multiuser Center for Biomolecular Innovation, Department of Physics, Instituto de Biociências, Letras e Ciências Exatas (Ibilce), Universidade Estadual Paulista (UNESP), São Jose do Rio Preto, Brazil
| | - Fabio R J Vieira
- Institut de Biologie de l'École Normale Supérieure (IBENS), Paris, France
| | - Mônika A Coronado
- Multiuser Center for Biomolecular Innovation, Department of Physics, Instituto de Biociências, Letras e Ciências Exatas (Ibilce), Universidade Estadual Paulista (UNESP), São Jose do Rio Preto, Brazil.,Institute of Biological Information Processing (IBI-7: Strucutral Biochemistry), Forschungszentrum Juelich, Juelich, Germany
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18
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Vatlin AA, Bekker OB, Lysenkova LN, Shchekotikhin AE, Danilenko VN. Bioinformatics analysis of genes of Streptomyces xinghaiensis (fradiae) ATCC 19609 with a focus on mutations conferring resistance to oligomycin A and its derivatives. J Glob Antimicrob Resist 2020; 22:47-53. [PMID: 32061812 DOI: 10.1016/j.jgar.2020.01.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 01/21/2020] [Accepted: 01/25/2020] [Indexed: 10/25/2022] Open
Abstract
OBJECTIVES The aim of this study was to obtain Streptomyces xinghaiensis (fradiae) ATCC 19609 mutants resistant to oligomycin A and its derivatives and to identify the underlying mechanism of resistance. This study was based on the premise that S. xinghaiensis ATCC 19609 contains several oligomycin A biological targets, explaining why the strain remains supersensitive to oligomycin A despite all efforts to obtain resistant mutants using standard genetic methods. METHODS The method to obtain oligomycin A-resistant mutants was performed in two steps: first, mutants slightly resistant to an oligomycin A derivative with an attenuated effect were obtained; and second, oligomycin A-resistant mutants were obtained from those mutants obtained earlier. The genomes of the mutants were then sequenced and a bioinformatics analysis of the detected mutations was conducted. RESULTS Mutants with seven mutations were required to obtain oligomycin A-resistant mutant strains of S. xinghaiensis characterised by a level of resistance comparable with that of the model organism Streptomyces lividans. Five of these mutations caused amino acid substitutions in the well-known oligomycin A biological target, namely the F0F1-ATP synthase A subunit, and the others caused amino acid substitutions in unexplored biological targets, including RecB-like recombinase, type IV helicase, DNA ligase and single-domain response regulator. CONCLUSION A new oligomycin resistance mechanism involving a pathway that repairs double-strand breaks in DNA known as non-homologous end joining (NHEJ) was discovered.
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Affiliation(s)
- Aleksey A Vatlin
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkina str. 3, 119333 Moscow, Russia.
| | - Olga B Bekker
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkina str. 3, 119333 Moscow, Russia
| | - Ludmila N Lysenkova
- Gause Institute of New Antibiotics, Bolschaya Pirogovskaya str. 11/1, 119867 Moscow, Russia
| | - Andrey E Shchekotikhin
- Gause Institute of New Antibiotics, Bolschaya Pirogovskaya str. 11/1, 119867 Moscow, Russia
| | - Valery N Danilenko
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkina str. 3, 119333 Moscow, Russia
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19
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Hawkins M, Dimude JU, Howard JAL, Smith AJ, Dillingham MS, Savery NJ, Rudolph CJ, McGlynn P. Direct removal of RNA polymerase barriers to replication by accessory replicative helicases. Nucleic Acids Res 2019; 47:5100-5113. [PMID: 30869136 PMCID: PMC6547429 DOI: 10.1093/nar/gkz170] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 02/22/2019] [Accepted: 03/08/2019] [Indexed: 11/24/2022] Open
Abstract
Bacterial genome duplication and transcription require simultaneous access to the same DNA template. Conflicts between the replisome and transcription machinery can lead to interruption of DNA replication and loss of genome stability. Pausing, stalling and backtracking of transcribing RNA polymerases add to this problem and present barriers to replisomes. Accessory helicases promote fork movement through nucleoprotein barriers and exist in viruses, bacteria and eukaryotes. Here, we show that stalled Escherichia coli transcription elongation complexes block reconstituted replisomes. This physiologically relevant block can be alleviated by the accessory helicase Rep or UvrD, resulting in the formation of full-length replication products. Accessory helicase action during replication-transcription collisions therefore promotes continued replication without leaving gaps in the DNA. In contrast, DinG does not promote replisome movement through stalled transcription complexes in vitro. However, our data demonstrate that DinG operates indirectly in vivo to reduce conflicts between replication and transcription. These results suggest that Rep and UvrD helicases operate on DNA at the replication fork whereas DinG helicase acts via a different mechanism.
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Affiliation(s)
- Michelle Hawkins
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Juachi U Dimude
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
| | | | - Abigail J Smith
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Mark S Dillingham
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Nigel J Savery
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Christian J Rudolph
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
| | - Peter McGlynn
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
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20
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Kovaľ T, Sudzinová P, Perháčová T, Trundová M, Skálová T, Fejfarová K, Šanderová H, Krásný L, Dušková J, Dohnálek J. Domain structure of HelD, an interaction partner of Bacillus subtilis RNA polymerase. FEBS Lett 2019; 593:996-1005. [PMID: 30972737 DOI: 10.1002/1873-3468.13385] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/29/2019] [Accepted: 04/01/2019] [Indexed: 01/02/2023]
Abstract
The HelD is a helicase-like protein binding to Bacillus subtilis RNA polymerase (RNAP), stimulating transcription in an ATP-dependent manner. Here, our small angle X-ray scattering data bring the first insights into the HelD structure: HelD is compact in shape and undergoes a conformational change upon substrate analog binding. Furthermore, the HelD domain structure is delineated, and a partial model of HelD is presented. In addition, the unique N-terminal domain of HelD is characterized as essential for its transcription-related function but not for ATPase activity, DNA binding, or binding to RNAP. The study provides a topological basis for further studies of the role of HelD in transcription.
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Affiliation(s)
- Tomáš Kovaľ
- Laboratory of Structure and Function of Biomolecules, Institute of Biotechnology of the Czech Academy of Sciences, v. v. i., Biocev, Vestec, Czech Republic
| | - Petra Sudzinová
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, v. v. i., Praha 4, Czech Republic
| | - Terézia Perháčová
- Laboratory of Structure and Function of Biomolecules, Institute of Biotechnology of the Czech Academy of Sciences, v. v. i., Biocev, Vestec, Czech Republic
| | - Mária Trundová
- Laboratory of Structure and Function of Biomolecules, Institute of Biotechnology of the Czech Academy of Sciences, v. v. i., Biocev, Vestec, Czech Republic
| | - Tereza Skálová
- Laboratory of Structure and Function of Biomolecules, Institute of Biotechnology of the Czech Academy of Sciences, v. v. i., Biocev, Vestec, Czech Republic
| | - Karla Fejfarová
- Laboratory of Structure and Function of Biomolecules, Institute of Biotechnology of the Czech Academy of Sciences, v. v. i., Biocev, Vestec, Czech Republic
| | - Hana Šanderová
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, v. v. i., Praha 4, Czech Republic
| | - Libor Krásný
- Laboratory of Microbial Genetics and Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, v. v. i., Praha 4, Czech Republic
| | - Jarmila Dušková
- Laboratory of Structure and Function of Biomolecules, Institute of Biotechnology of the Czech Academy of Sciences, v. v. i., Biocev, Vestec, Czech Republic
| | - Jan Dohnálek
- Laboratory of Structure and Function of Biomolecules, Institute of Biotechnology of the Czech Academy of Sciences, v. v. i., Biocev, Vestec, Czech Republic
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21
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Ordabayev YA, Nguyen B, Niedziela-Majka A, Lohman TM. Regulation of UvrD Helicase Activity by MutL. J Mol Biol 2018; 430:4260-4274. [PMID: 30171840 DOI: 10.1016/j.jmb.2018.08.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 08/03/2018] [Accepted: 08/23/2018] [Indexed: 11/18/2022]
Abstract
Escherichia coli UvrD is a superfamily 1 helicase/translocase involved in multiple DNA metabolic processes including methyl-directed mismatch DNA repair. Although a UvrD monomer can translocate along single-stranded DNA, a UvrD dimer is needed for processive helicase activity in vitro. E. coli MutL, a regulatory protein involved in methyl-directed mismatch repair, stimulates UvrD helicase activity; however, the mechanism is not well understood. Using single-molecule fluorescence and ensemble approaches, we find that a single MutL dimer can activate latent UvrD monomer helicase activity. However, we also find that MutL stimulates UvrD dimer helicase activity. We further find that MutL enhances the DNA-unwinding processivity of UvrD. Hence, MutL acts as a processivity factor by binding to and presumably moving along with UvrD to facilitate DNA unwinding.
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Affiliation(s)
- Yerdos A Ordabayev
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Ave., Box 8231, St. Louis, MO 63110, United States
| | - Binh Nguyen
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Ave., Box 8231, St. Louis, MO 63110, United States
| | - Anita Niedziela-Majka
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Ave., Box 8231, St. Louis, MO 63110, United States
| | - Timothy M Lohman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Ave., Box 8231, St. Louis, MO 63110, United States.
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22
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Kaur G, Kapoor S, Thakur KG. Bacillus subtilis HelD, an RNA Polymerase Interacting Helicase, Forms Amyloid-Like Fibrils. Front Microbiol 2018; 9:1934. [PMID: 30186259 PMCID: PMC6111841 DOI: 10.3389/fmicb.2018.01934] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 07/30/2018] [Indexed: 12/26/2022] Open
Abstract
HelD, an RNA polymerase binding protein from Bacillus subtilis, stimulates transcription and helps in timely adaptation of cells under diverse environmental conditions. At present, no structural information is available for HelD. In the current study, we performed size exclusion chromatography coupled to small angle X-ray scattering (SEC-SAXS) which suggests that HelD is predominantly monomeric and globular in solution. Using combination of size exclusion chromatography and analytical ultracentrifugation, we also show that HelD has a tendency to form higher order oligomers in solution. CD experiments suggest that HelD has both α-helical (∼35%) and β sheet (∼26%) secondary structural elements. Thermal melting experiments suggest that even at 90°C, there is only about 30% loss in secondary structural contents with Tm of 44°C. However, with the increase in temperature, there was a gain in the β-sheet content and significant irreversible loss of α-helical content. Using a combination of X-ray fiber diffraction analysis, and dye based assays including Thioflavin-T based fluorescence and Congo red binding assays, we discovered that HelD forms amyloid-like fibrils at physiologically relevant conditions in vitro. Using confocal imaging, we further show that HelD forms amyloid inclusions in Escherichia coli. Bioinformatics-based sequence analysis performed using three independent web-based servers suggests that HelD has more than 20 hot-spots spread across the sequence that may aid the formation of amyloid-like fibrils. This discovery adds one more member to the growing list of amyloid or amyloid-like fibril forming cytosolic proteins in bacteria. Future studies aimed at resolving the function of amyloid-like fibrils or amyloid inclusions may help better understand their role, if any, in the bacterial physiology.
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Affiliation(s)
- Gundeep Kaur
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India
| | - Srajan Kapoor
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India
| | - Krishan G Thakur
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India
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23
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Sanders K, Lin CL, Smith AJ, Cronin N, Fisher G, Eftychidis V, McGlynn P, Savery NJ, Wigley DB, Dillingham MS. The structure and function of an RNA polymerase interaction domain in the PcrA/UvrD helicase. Nucleic Acids Res 2017; 45:3875-3887. [PMID: 28160601 PMCID: PMC5397179 DOI: 10.1093/nar/gkx074] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 01/25/2017] [Indexed: 11/14/2022] Open
Abstract
The PcrA/UvrD helicase functions in multiple pathways that promote bacterial genome stability including the suppression of conflicts between replication and transcription and facilitating the repair of transcribed DNA. The reported ability of PcrA/UvrD to bind and backtrack RNA polymerase (1,2) might be relevant to these functions, but the structural basis for this activity is poorly understood. In this work, we define a minimal RNA polymerase interaction domain in PcrA, and report its crystal structure at 1.5 Å resolution. The domain adopts a Tudor-like fold that is similar to other RNA polymerase interaction domains, including that of the prototype transcription-repair coupling factor Mfd. Removal or mutation of the interaction domain reduces the ability of PcrA/UvrD to interact with and to remodel RNA polymerase complexes in vitro. The implications of this work for our understanding of the role of PcrA/UvrD at the interface of DNA replication, transcription and repair are discussed.
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Affiliation(s)
- Kelly Sanders
- DNA:Protein Interactions Unit, School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Chia-Liang Lin
- Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK and Section of Structural Biology, Department of Medicine, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Abigail J Smith
- DNA:Protein Interactions Unit, School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Nora Cronin
- Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK and Section of Structural Biology, Department of Medicine, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Gemma Fisher
- DNA:Protein Interactions Unit, School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | | | - Peter McGlynn
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Nigel J Savery
- DNA:Protein Interactions Unit, School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Dale B Wigley
- Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK and Section of Structural Biology, Department of Medicine, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Mark S Dillingham
- DNA:Protein Interactions Unit, School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
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24
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Torres R, Romero H, Rodríguez-Cerrato V, Alonso JC. Interplay between Bacillus subtilis RecD2 and the RecG or RuvAB helicase in recombinational repair. DNA Repair (Amst) 2017; 55:40-46. [DOI: 10.1016/j.dnarep.2017.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 05/08/2017] [Accepted: 05/10/2017] [Indexed: 10/24/2022]
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25
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Abstract
Transcription-coupled DNA repair (TCR) acts on lesions in the transcribed strand of active genes. Helix distorting adducts and other forms of DNA damage often interfere with the progression of the transcription apparatus. Prolonged stalling of RNA polymerase can promote genome instability and also induce cell cycle arrest and apoptosis. These generally unfavorable events are counteracted by RNA polymerase-mediated recruitment of specific proteins to the sites of DNA damage to perform TCR and eventually restore transcription. In this perspective we discuss the decision-making process to employ TCR and we elucidate the intricate biochemical pathways leading to TCR in E. coli and human cells.
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Affiliation(s)
- Bibhusita Pani
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA.
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26
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Conflict Resolution in the Genome: How Transcription and Replication Make It Work. Cell 2017; 167:1455-1467. [PMID: 27912056 DOI: 10.1016/j.cell.2016.09.053] [Citation(s) in RCA: 177] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 09/20/2016] [Accepted: 09/27/2016] [Indexed: 01/12/2023]
Abstract
The complex machineries involved in replication and transcription translocate along the same DNA template, often in opposing directions and at different rates. These processes routinely interfere with each other in prokaryotes, and mounting evidence now suggests that RNA polymerase complexes also encounter replication forks in higher eukaryotes. Indeed, cells rely on numerous mechanisms to avoid, tolerate, and resolve such transcription-replication conflicts, and the absence of these mechanisms can lead to catastrophic effects on genome stability and cell viability. In this article, we review the cellular responses to transcription-replication conflicts and highlight how these inevitable encounters shape the genome and impact diverse cellular processes.
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27
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28
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Selby CP. Mfd Protein and Transcription-Repair Coupling in Escherichia coli. Photochem Photobiol 2017; 93:280-295. [PMID: 27864884 DOI: 10.1111/php.12675] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 10/18/2016] [Indexed: 01/30/2023]
Abstract
In 1989, transcription-repair coupling (TRC) was first described in Escherichia coli, as the transcription-dependent, preferential nucleotide excision repair (NER) of UV photoproducts located in the template DNA strand. This finding led to pioneering biochemical studies of TRC in the laboratory of Professor Aziz Sancar, where, at the time, major contributions were being made toward understanding the roles of the UvrA, UvrB and UvrC proteins in NER. When the repair studies were extended to TRC, template but not coding strand lesions were found to block RNA polymerase (RNAP) in vitro, and unexpectedly, the blocked RNAP inhibited NER. A transcription-repair coupling factor, also called Mfd protein, was found to remove the blocked RNAP, deliver the repair enzyme to the lesion and thereby mediate more rapid repair of the transcription-blocking lesion compared with lesions elsewhere. Structural and functional analyses of Mfd protein revealed helicase motifs responsible for ATP hydrolysis and DNA binding, and regions that interact with RNAP and UvrA. These and additional studies provided a basis upon which other investigators, in following decades, have characterized fascinating and unexpected structural and mechanistic features of Mfd, revealed the possible existence of additional pathways of TRC and discovered additional roles of Mfd in the cell.
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Affiliation(s)
- Christopher P Selby
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC
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Abstract
DNA topological transitions occur when replication forks encounter other DNA transactions such as transcription. Failure in resolving such conflicts leads to generation of aberrant replication and transcription intermediates that might have adverse effects on genome stability. Cells have evolved numerous surveillance mechanisms to avoid, tolerate, and resolve such replication-transcription conflicts. Defects or non-coordination in such cellular mechanisms might have catastrophic effect on cell viability. In this chapter, we review consequences of replication encounters with transcription and its associated events, topological challenges, and how these inevitable conflicts alter the genome structure and functions.
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30
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A Magic Spot in Genome Maintenance. Trends Genet 2016; 33:58-67. [PMID: 27931778 DOI: 10.1016/j.tig.2016.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/02/2016] [Accepted: 11/03/2016] [Indexed: 01/02/2023]
Abstract
Nucleotide excision repair (NER) is the key DNA repair system that eliminates the majority of DNA helix-distorting lesions. RNA polymerase (RNAP) expedites the recognition of DNA damage by NER components via transcription-coupled DNA repair (TCR). In bacteria, a modified nucleotide ppGpp ('magic spot') is a pleiotropic second messenger that mediates the response to nutrient deficiencies by altering the initiation properties of RNAP. In this review, we discuss newly elucidated roles of guanosine 5'-diphosphate 3'-diphosphate (ppGpp) in transcription elongation that couple this alarmone to DNA damage repair and maintenance.
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31
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Gifsy-1 Prophage IsrK with Dual Function as Small and Messenger RNA Modulates Vital Bacterial Machineries. PLoS Genet 2016; 12:e1005975. [PMID: 27057757 PMCID: PMC4825925 DOI: 10.1371/journal.pgen.1005975] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 03/14/2016] [Indexed: 11/20/2022] Open
Abstract
While an increasing number of conserved small regulatory RNAs (sRNAs) are known to function in general bacterial physiology, the roles and modes of action of sRNAs from horizontally acquired genomic regions remain little understood. The IsrK sRNA of Gifsy-1 prophage of Salmonella belongs to the latter class. This regulatory RNA exists in two isoforms. The first forms, when a portion of transcripts originating from isrK promoter reads-through the IsrK transcription-terminator producing a translationally inactive mRNA target. Acting in trans, the second isoform, short IsrK RNA, binds the inactive transcript rendering it translationally active. By switching on translation of the first isoform, short IsrK indirectly activates the production of AntQ, an antiterminator protein located upstream of isrK. Expression of antQ globally interferes with transcription termination resulting in bacterial growth arrest and ultimately cell death. Escherichia coli and Salmonella cells expressing AntQ display condensed chromatin morphology and localization of UvrD to the nucleoid. The toxic phenotype of AntQ can be rescued by co-expression of the transcription termination factor, Rho, or RNase H, which protects genomic DNA from breaks by resolving R-loops. We propose that AntQ causes conflicts between transcription and replication machineries and thus promotes DNA damage. The isrK locus represents a unique example of an island-encoded sRNA that exerts a highly complex regulatory mechanism to tune the expression of a toxic protein.
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32
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Abstract
Plasmids are DNA entities that undergo controlled replication independent of the chromosomal DNA, a crucial step that guarantees the prevalence of the plasmid in its host. DNA replication has to cope with the incapacity of the DNA polymerases to start de novo DNA synthesis, and different replication mechanisms offer diverse solutions to this problem. Rolling-circle replication (RCR) is a mechanism adopted by certain plasmids, among other genetic elements, that represents one of the simplest initiation strategies, that is, the nicking by a replication initiator protein on one parental strand to generate the primer for leading-strand initiation and a single priming site for lagging-strand synthesis. All RCR plasmid genomes consist of a number of basic elements: leading strand initiation and control, lagging strand origin, phenotypic determinants, and mobilization, generally in that order of frequency. RCR has been mainly characterized in Gram-positive bacterial plasmids, although it has also been described in Gram-negative bacterial or archaeal plasmids. Here we aim to provide an overview of the RCR plasmids' lifestyle, with emphasis on their characteristic traits, promiscuity, stability, utility as vectors, etc. While RCR is one of the best-characterized plasmid replication mechanisms, there are still many questions left unanswered, which will be pointed out along the way in this review.
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Martínez E, Campos-Gómez J, Barre FX. CTXϕ: Exploring new alternatives in host factor-mediated filamentous phage replications. BACTERIOPHAGE 2016; 6:e1128512. [PMID: 27607139 DOI: 10.1080/21597081.2015.1128512] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/24/2015] [Indexed: 10/22/2022]
Abstract
For a long time Ff phages from Escherichia coli provided the majority of the knowledge about the rolling circle replication mechanism of filamentous phages. Host factors involved in coliphages replication have been fully identified. Based on these studies, the function of Rep protein as the accessory helicase directly implicated in filamentous phage replication was considered a paradigm. We recently reported that the replication of some filamentous phages from Vibrio cholerae, including the cholera toxin phage CTXϕ, depended on the accessory helicase UvrD instead of Rep. We also identified HU protein as one of the host factors involved in CTXϕ and VGJϕ replication. The requirement of UvrD and HU for rolling circle replication was previously reported in some family of plasmids but had no precedent in filamentous phages. Here, we enrich the discussion of our results and present new preliminary data highlighting remarkable divergence in the lifestyle of filamentous phages.
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Affiliation(s)
- Eriel Martínez
- Southern Research Institute, Department of Biochemistry and Molecular Biology, Drug Discovery Division, Birmingham, AL, USA; Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Univ. Paris Sud, Gif sur Yvette, France
| | - Javier Campos-Gómez
- Southern Research Institute, Department of Biochemistry and Molecular Biology, Drug Discovery Division , Birmingham, AL, USA
| | - François-Xavier Barre
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Univ. Paris Sud , Gif sur Yvette, France
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Bacterial Transcription as a Target for Antibacterial Drug Development. Microbiol Mol Biol Rev 2016; 80:139-60. [PMID: 26764017 DOI: 10.1128/mmbr.00055-15] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Transcription, the first step of gene expression, is carried out by the enzyme RNA polymerase (RNAP) and is regulated through interaction with a series of protein transcription factors. RNAP and its associated transcription factors are highly conserved across the bacterial domain and represent excellent targets for broad-spectrum antibacterial agent discovery. Despite the numerous antibiotics on the market, there are only two series currently approved that target transcription. The determination of the three-dimensional structures of RNAP and transcription complexes at high resolution over the last 15 years has led to renewed interest in targeting this essential process for antibiotic development by utilizing rational structure-based approaches. In this review, we describe the inhibition of the bacterial transcription process with respect to structural studies of RNAP, highlight recent progress toward the discovery of novel transcription inhibitors, and suggest additional potential antibacterial targets for rational drug design.
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Abstract
Bacteria lack subcellular compartments and harbor a single RNA polymerase that synthesizes both structural and protein-coding RNAs, which are cotranscriptionally processed by distinct pathways. Nascent rRNAs fold into elaborate secondary structures and associate with ribosomal proteins, whereas nascent mRNAs are translated by ribosomes. During elongation, nucleic acid signals and regulatory proteins modulate concurrent RNA-processing events, instruct RNA polymerase where to pause and terminate transcription, or act as roadblocks to the moving enzyme. Communications among complexes that carry out transcription, translation, repair, and other cellular processes ensure timely execution of the gene expression program and survival under conditions of stress. This network is maintained by auxiliary proteins that act as bridges between RNA polymerase, ribosome, and repair enzymes, blurring boundaries between separate information-processing steps and making assignments of unique regulatory functions meaningless. Understanding the regulation of transcript elongation thus requires genome-wide approaches, which confirm known and reveal new regulatory connections.
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Affiliation(s)
| | - Irina Artsimovitch
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210;
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Merrikh CN, Brewer BJ, Merrikh H. The B. subtilis Accessory Helicase PcrA Facilitates DNA Replication through Transcription Units. PLoS Genet 2015; 11:e1005289. [PMID: 26070154 PMCID: PMC4466434 DOI: 10.1371/journal.pgen.1005289] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 05/18/2015] [Indexed: 11/18/2022] Open
Abstract
In bacteria the concurrence of DNA replication and transcription leads to potentially deleterious encounters between the two machineries, which can occur in either the head-on (lagging strand genes) or co-directional (leading strand genes) orientations. These conflicts lead to replication fork stalling and can destabilize the genome. Both eukaryotic and prokaryotic cells possess resolution factors that reduce the severity of these encounters. Though Escherichia coli accessory helicases have been implicated in the mitigation of head-on conflicts, direct evidence of these proteins mitigating co-directional conflicts is lacking. Furthermore, the endogenous chromosomal regions where these helicases act, and the mechanism of recruitment, have not been identified. We show that the essential Bacillus subtilis accessory helicase PcrA aids replication progression through protein coding genes of both head-on and co-directional orientations, as well as rRNA and tRNA genes. ChIP-Seq experiments show that co-directional conflicts at highly transcribed rRNA, tRNA, and head-on protein coding genes are major targets of PcrA activity on the chromosome. Partial depletion of PcrA renders cells extremely sensitive to head-on conflicts, linking the essential function of PcrA to conflict resolution. Furthermore, ablating PcrA’s ATPase/helicase activity simultaneously increases its association with conflict regions, while incapacitating its ability to mitigate conflicts, and leads to cell death. In contrast, disruption of PcrA’s C-terminal RNA polymerase interaction domain does not impact its ability to mitigate conflicts between replication and transcription, its association with conflict regions, or cell survival. Altogether, this work establishes PcrA as an essential factor involved in mitigating transcription-replication conflicts and identifies chromosomal regions where it routinely acts. As both conflicts and accessory helicases are found in all domains of life, these results are broadly relevant. In bacteria the concurrence of DNA replication and transcription leads to potentially deleterious encounters between the two machineries. These encounters can destabilize the genome and lead to mutations. Both eukaryotic and prokaryotic cells possess conflict resolution factors that reduce the detrimental effects of these collisions. In this study we show that without the essential Bacillus subtilis accessory DNA helicase, PcrA, the replication machinery slows down at certain regions of the chromosome in a transcription-dependent manner. PcrA is essential to life but incomplete depletion of PcrA only partially inhibits cell survival. We find that, under these conditions, partial survival defects are significantly exacerbated in the presence of a single severe conflict. In summary our work identifies a high degree of conservation for accessory helicase function in conflict resolution, directly establishes PcrA’s role in co-directional conflict resolution, and maps the natural chromosomal regions where such activities are routinely needed. Because both conflicts and accessory helicases are found in all domains of life, the results of this work are broadly relevant.
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Affiliation(s)
- Christopher N. Merrikh
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Bonita J. Brewer
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Houra Merrikh
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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Functions that Protect Escherichia coli from Tightly Bound DNA-Protein Complexes Created by Mutant EcoRII Methyltransferase. PLoS One 2015; 10:e0128092. [PMID: 25993347 PMCID: PMC4437897 DOI: 10.1371/journal.pone.0128092] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 04/23/2015] [Indexed: 11/19/2022] Open
Abstract
Expression of mutant EcoRII methyltransferase protein (M.EcoRII-C186A) in Escherichia coli leads to tightly bound DNA-protein complexes (TBCs), located sporadically on the chromosome rather than in tandem arrays. The mechanisms behind the lethality induced by such sporadic TBCs are not well studied, nor is it clear whether very tight binding but non-covalent complexes are processed in the same way as covalent DNA-protein crosslinks (DPCs). Using 2D gel electrophoresis, we found that TBCs induced by M.EcoRII-C186A block replication forks in vivo. Specific bubble molecules were detected as spots on the 2D gel, only when M.EcoRII-C186A was induced, and a mutation that eliminates a specific EcoRII methylation site led to disappearance of the corresponding spot. We also performed a candidate gene screen for mutants that are hypersensitive to TBCs induced by M.EcoRII-C186A. We found several gene products necessary for protection against these TBCs that are known to also protect against DPCs induced with wild-type M.EcoRII (after 5-azacytidine incorporation): RecA, RecBC, RecG, RuvABC, UvrD, FtsK, XerCD and SsrA (tmRNA). In contrast, the RecFOR pathway and Rep helicase are needed for protection against TBCs but not DPCs induced by M.EcoRII. We propose that stalled fork processing by RecFOR and RecA promotes release of tightly bound (but non-covalent) blocking proteins, perhaps by licensing Rep helicase-driven dissociation of the blocking M.EcoRII-C186A. Our studies also argued against the involvement of several proteins that might be expected to protect against TBCs. We took the opportunity to directly compare the sensitivity of all tested mutants to two quinolone antibiotics, which target bacterial type II topoisomerases and induce a unique form of DPC. We uncovered rep, ftsK and xerCD as novel quinolone hypersensitive mutants, and also obtained evidence against the involvement of a number of functions that might be expected to protect against quinolones.
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Kamarthapu V, Nudler E. Rethinking transcription coupled DNA repair. Curr Opin Microbiol 2015; 24:15-20. [PMID: 25596348 DOI: 10.1016/j.mib.2014.12.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 12/22/2014] [Accepted: 12/30/2014] [Indexed: 11/26/2022]
Abstract
Nucleotide excision repair (NER) is an evolutionarily conserved, multistep process that can detect a wide variety of DNA lesions. Transcription coupled repair (TCR) is a subpathway of NER that repairs the transcribed DNA strand faster than the rest of the genome. RNA polymerase (RNAP) stalled at DNA lesions mediates the recruitment of NER enzymes to the damage site. In this review we focus on a newly identified bacterial TCR pathway in which the NER enzyme UvrD, in conjunction with NusA, plays a major role in initiating the repair process. We discuss the tradeoff between the new and conventional models of TCR, how and when each pathway operates to repair DNA damage, and the necessity of pervasive transcription in maintaining genome integrity.
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Affiliation(s)
- Venu Kamarthapu
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, New York University School of Medicine, New York, NY 10016, USA.
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39
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Accessory Replicative Helicases and the Replication of Protein-Bound DNA. J Mol Biol 2014; 426:3917-3928. [DOI: 10.1016/j.jmb.2014.10.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/29/2014] [Accepted: 10/06/2014] [Indexed: 12/29/2022]
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40
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Wiedermannová J, Sudzinová P, Kovaľ T, Rabatinová A, Šanderova H, Ramaniuk O, Rittich Š, Dohnálek J, Fu Z, Halada P, Lewis P, Krásny L. Characterization of HelD, an interacting partner of RNA polymerase from Bacillus subtilis. Nucleic Acids Res 2014; 42:5151-63. [PMID: 24520113 PMCID: PMC4005671 DOI: 10.1093/nar/gku113] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Bacterial RNA polymerase (RNAP) is an essential multisubunit protein complex required for gene expression. Here, we characterize YvgS (HelD) from Bacillus subtilis, a novel binding partner of RNAP. We show that HelD interacts with RNAP-core between the secondary channel of RNAP and the alpha subunits. Importantly, we demonstrate that HelD stimulates transcription in an ATP-dependent manner by enhancing transcriptional cycling and elongation. We demonstrate that the stimulatory effect of HelD can be amplified by a small subunit of RNAP, delta. In vivo, HelD is not essential but it is required for timely adaptations of the cell to changing environment. In summary, this study establishes HelD as a valid component of the bacterial transcription machinery.
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Affiliation(s)
- Jana Wiedermannová
- Laboratory of Molecular Genetics of Bacteria, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic, Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Prague 12843, Czech Republic, Department of Structure Analysis of Biomacromolecules, Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague 16206, Czech Republic, Laboratory of Structure and Function of Biomolecules, Institute of Biotechnology, Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia and Laboratory of Molecular Structure Characterization, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic
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