1
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Johannesman A, Carlson NA, LeRoux M. Phages carry orphan antitoxin-like enzymes to neutralize the DarTG1 toxin-antitoxin defense system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.11.602962. [PMID: 39026772 PMCID: PMC11257639 DOI: 10.1101/2024.07.11.602962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
The astounding number of anti-phage defenses encoded by bacteria is countered by an elaborate set of phage counter-defenses, though their evolutionary origins are often unknown. Here, we discover an orphan antitoxin counter-defense element in T4-like phages that can overcome the bacterial toxin-antitoxin phage defense system, DarTG1. The DarT1 toxin, an ADP-ribosyltransferase, modifies phage DNA to prevent replication while its cognate antitoxin, DarG1, is an ADP-ribosylglycohydrolase that reverses these modifications in uninfected bacteria. The orphan phage DarG1-like protein, which we term anti-DarT factor NADAR (AdfN), removes ADP-ribose modifications from phage DNA during infection thereby enabling replication in DarTG1-containing bacteria. AdfN, like DarG1, is in the NADAR superfamily of ADP-ribosylglycohydrolases found across domains of life. We find divergent NADAR proteins in unrelated phages that likewise exhibit anti-DarTG1 activity, underscoring the importance of ADP-ribosylation in bacterial-phage interactions, and revealing the function of a substantial subset of the NADAR superfamily.
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Affiliation(s)
- Anna Johannesman
- Department of Molecular Microbiology, Washington University in Saint Louis School of Medicine, Saint Louis, MO 63110, USA
| | - Nico A. Carlson
- Department of Molecular Microbiology, Washington University in Saint Louis School of Medicine, Saint Louis, MO 63110, USA
| | - Michele LeRoux
- Department of Molecular Microbiology, Washington University in Saint Louis School of Medicine, Saint Louis, MO 63110, USA
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2
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Carabias A, Camara-Wilpert S, Mestre MR, Lopéz-Méndez B, Hendriks IA, Zhao R, Pape T, Fuglsang A, Luk SHC, Nielsen ML, Pinilla-Redondo R, Montoya G. Retron-Eco1 assembles NAD +-hydrolyzing filaments that provide immunity against bacteriophages. Mol Cell 2024; 84:2185-2202.e12. [PMID: 38788717 DOI: 10.1016/j.molcel.2024.05.001] [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: 09/26/2023] [Revised: 03/15/2024] [Accepted: 05/01/2024] [Indexed: 05/26/2024]
Abstract
Retrons are toxin-antitoxin systems protecting bacteria against bacteriophages via abortive infection. The Retron-Eco1 antitoxin is formed by a reverse transcriptase (RT) and a non-coding RNA (ncRNA)/multi-copy single-stranded DNA (msDNA) hybrid that neutralizes an uncharacterized toxic effector. Yet, the molecular mechanisms underlying phage defense remain unknown. Here, we show that the N-glycosidase effector, which belongs to the STIR superfamily, hydrolyzes NAD+ during infection. Cryoelectron microscopy (cryo-EM) analysis shows that the msDNA stabilizes a filament that cages the effector in a low-activity state in which ADPr, a NAD+ hydrolysis product, is covalently linked to the catalytic E106 residue. Mutations shortening the msDNA induce filament disassembly and the effector's toxicity, underscoring the msDNA role in immunity. Furthermore, we discovered a phage-encoded Retron-Eco1 inhibitor (U56) that binds ADPr, highlighting the intricate interplay between retron systems and phage evolution. Our work outlines the structural basis of Retron-Eco1 defense, uncovering ADPr's pivotal role in immunity.
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Affiliation(s)
- Arturo Carabias
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark.
| | - Sarah Camara-Wilpert
- Section of Microbiology, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Mario Rodríguez Mestre
- Section of Microbiology, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Blanca Lopéz-Méndez
- Protein Purification and Characterization Facility, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Ivo A Hendriks
- Proteomics Department, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Ruiliang Zhao
- Section of Microbiology, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Tillmann Pape
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark; Core Facility for Integrated Microscopy (CFIM), Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Anders Fuglsang
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Sean Hoi-Ching Luk
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Michael L Nielsen
- Proteomics Department, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Rafael Pinilla-Redondo
- Section of Microbiology, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark.
| | - Guillermo Montoya
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark.
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3
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Cihlova B, Lu Y, Mikoč A, Schuller M, Ahel I. Specificity of DNA ADP-Ribosylation Reversal by NADARs. Toxins (Basel) 2024; 16:208. [PMID: 38787060 PMCID: PMC11125620 DOI: 10.3390/toxins16050208] [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: 03/18/2024] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024] Open
Abstract
Recent discoveries establish DNA and RNA as bona fide substrates for ADP-ribosylation. NADAR ("NAD- and ADP-ribose"-associated) enzymes reverse guanine ADP-ribosylation and serve as antitoxins in the DarT-NADAR operon. Although NADARs are widespread across prokaryotes, eukaryotes, and viruses, their specificity and broader physiological roles remain poorly understood. Using phylogenetic and biochemical analyses, we further explore de-ADP-ribosylation activity and antitoxin functions of NADAR domains. We demonstrate that different subfamilies of NADAR proteins from representative E. coli strains and an E. coli-infecting phage retain biochemical activity while displaying specificity in providing protection from toxic guanine ADP-ribosylation in cells. Furthermore, we identify a myxobacterial enzyme within the YbiA subfamily that functions as an antitoxin for its associated DarT-unrelated ART toxin, which we termed YarT, thus presenting a hitherto uncharacterised ART-YbiA toxin-antitoxin pair. Our studies contribute to the burgeoning field of DNA ADP-ribosylation, supporting its physiological relevance within and beyond bacterial toxin-antitoxin systems. Notably, the specificity and confinement of NADARs to non-mammals infer their potential as highly specific targets for antimicrobial drugs with minimal off-target effects.
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Affiliation(s)
- Bara Cihlova
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; (B.C.); (Y.L.)
| | - Yang Lu
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; (B.C.); (Y.L.)
| | - Andreja Mikoč
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia;
| | - Marion Schuller
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; (B.C.); (Y.L.)
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; (B.C.); (Y.L.)
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4
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Deep A, Singh L, Kaur J, Velusamy M, Bhardwaj P, Singh R, Thakur KG. Structural insights into DarT toxin neutralization by cognate DarG antitoxin: ssDNA mimicry by DarG C-terminal domain keeps the DarT toxin inhibited. Structure 2023; 31:780-789.e4. [PMID: 37167974 DOI: 10.1016/j.str.2023.04.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 03/20/2023] [Accepted: 04/14/2023] [Indexed: 05/13/2023]
Abstract
In the DarTG toxin-antitoxin system, the DarT toxin ADP-ribosylates single-stranded DNA (ssDNA), which stalls DNA replication and plays a crucial role in controlling bacterial growth and bacteriophage infection. This toxic activity is reversed by the N-terminal macrodomain of the cognate antitoxin DarG. DarG also binds DarT, but the role of these interactions in DarT neutralization is unknown. Here, we report that the C-terminal domain of DarG (DarG toxin-binding domain [DarGTBD]) interacts with DarT to form a 1:1 stoichiometric heterodimeric complex. We determined the 2.2 Å resolution crystal structure of the Mycobacterium tuberculosis DarT-DarGTBD complex. The comparative structural analysis reveals that DarGTBD interacts with DarT at the DarT/ssDNA interaction interface, thus sterically occluding substrate ssDNA binding and consequently inactivating toxin by direct protein-protein interactions. Our data support a unique two-layered DarT toxin neutralization mechanism of DarG, which is important in keeping the toxin molecules in check under normal growth conditions.
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Affiliation(s)
- Amar Deep
- Structural Biology Laboratory, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh 160036, India
| | - Latika Singh
- Structural Biology Laboratory, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh 160036, India
| | - Japleen Kaur
- Structural Biology Laboratory, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh 160036, India
| | - Maheshwaran Velusamy
- Structural Biology Laboratory, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh 160036, India
| | - Pushpanjali Bhardwaj
- Structural Biology Laboratory, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh 160036, India
| | - Ramandeep Singh
- Infection and Immunology Group, Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, NCR-Biotech Science Cluster, 3rd Milestone, Faridabad Gurugram Expressway, Faridabad-121001, India
| | - Krishan Gopal Thakur
- Structural Biology Laboratory, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh 160036, India.
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5
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Cox MM, Goodman MF, Keck JL, van Oijen A, Lovett ST, Robinson A. Generation and Repair of Postreplication Gaps in Escherichia coli. Microbiol Mol Biol Rev 2023; 87:e0007822. [PMID: 37212693 PMCID: PMC10304936 DOI: 10.1128/mmbr.00078-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023] Open
Abstract
When replication forks encounter template lesions, one result is lesion skipping, where the stalled DNA polymerase transiently stalls, disengages, and then reinitiates downstream to leave the lesion behind in a postreplication gap. Despite considerable attention in the 6 decades since postreplication gaps were discovered, the mechanisms by which postreplication gaps are generated and repaired remain highly enigmatic. This review focuses on postreplication gap generation and repair in the bacterium Escherichia coli. New information to address the frequency and mechanism of gap generation and new mechanisms for their resolution are described. There are a few instances where the formation of postreplication gaps appears to be programmed into particular genomic locations, where they are triggered by novel genomic elements.
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Affiliation(s)
- Michael M. Cox
- Department of Biochemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Myron F. Goodman
- Department of Biological Sciences, University of Southern California, University Park, Los Angeles, California, USA
- Department of Chemistry, University of Southern California, University Park, Los Angeles, California, USA
| | - James L. Keck
- Department of Biological Chemistry, University of Wisconsin—Madison School of Medicine, Madison, Wisconsin, USA
| | - Antoine van Oijen
- Molecular Horizons, University of Wollongong, Wollongong, New South Wales, Australia
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales, Australia
| | - Susan T. Lovett
- Department of Biology, Brandeis University, Waltham, Massachusetts, USA
| | - Andrew Robinson
- Molecular Horizons, University of Wollongong, Wollongong, New South Wales, Australia
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales, Australia
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6
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Schuller M, Raggiaschi R, Mikolcevic P, Rack JGM, Ariza A, Zhang Y, Ledermann R, Tang C, Mikoc A, Ahel I. Molecular basis for the reversible ADP-ribosylation of guanosine bases. Mol Cell 2023:S1097-2765(23)00457-4. [PMID: 37390817 DOI: 10.1016/j.molcel.2023.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 04/13/2023] [Accepted: 06/08/2023] [Indexed: 07/02/2023]
Abstract
Modification of nucleic acids by ADP-ribosylation is catalyzed by various ADP-ribosyltransferases, including the DarT enzyme. The latter is part of the bacterial toxin-antitoxin (TA) system DarTG, which was shown to provide control of DNA replication and bacterial growth as well as protection against bacteriophages. Two subfamilies have been identified, DarTG1 and DarTG2, which are distinguished by their associated antitoxins. While DarTG2 catalyzes reversible ADP-ribosylation of thymidine bases employing a macrodomain as antitoxin, the DNA ADP-ribosylation activity of DarTG1 and the biochemical function of its antitoxin, a NADAR domain, are as yet unknown. Using structural and biochemical approaches, we show that DarT1-NADAR is a TA system for reversible ADP-ribosylation of guanosine bases. DarT1 evolved the ability to link ADP-ribose to the guanine amino group, which is specifically hydrolyzed by NADAR. We show that guanine de-ADP-ribosylation is also conserved among eukaryotic and non-DarT-associated NADAR members, indicating a wide distribution of reversible guanine modifications beyond DarTG systems.
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Affiliation(s)
- Marion Schuller
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | - Petra Mikolcevic
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Johannes G M Rack
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Antonio Ariza
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - YuGeng Zhang
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | - Christoph Tang
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Andreja Mikoc
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
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7
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Henry C, Mbele N, Cox MM. RecF protein targeting to postreplication (daughter strand) gaps I: DNA binding by RecF and RecFR. Nucleic Acids Res 2023; 51:5699-5713. [PMID: 37125642 PMCID: PMC10287957 DOI: 10.1093/nar/gkad311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 04/09/2023] [Accepted: 04/27/2023] [Indexed: 05/02/2023] Open
Abstract
In bacteria, the repair of post-replication gaps by homologous recombination requires the action of the recombination mediator proteins RecF, RecO and RecR. Whereas the role of the RecOR proteins to displace the single strand binding protein (SSB) and facilitate RecA loading is clear, how RecF mediates targeting of the system to appropriate sites remains enigmatic. The most prominent hypothesis relies on specific RecF binding to gap ends. To test this idea, we present a detailed examination of RecF and RecFR binding to more than 40 DNA substrates of varying length and structure. Neither RecF nor the RecFR complex exhibited specific DNA binding that can explain the targeting of RecF(R) to post-replication gaps. RecF(R) bound to dsDNA and ssDNA of sufficient length with similar facility. DNA binding was highly ATP-dependent. Most measured Kd values fell into a range of 60-180 nM. The addition of ssDNA extensions on duplex substrates to mimic gap ends or CPD lesions produces only subtle increases or decreases in RecF(R) affinity. Significant RecFR binding cooperativity was evident with many DNA substrates. The results indicate that RecF or RecFR targeting to post-replication gaps must rely on factors not yet identified, perhaps involving interactions with additional proteins.
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Affiliation(s)
- Camille Henry
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA
| | - Neema Mbele
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA
| | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA
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8
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Boss L, Kędzierska B. Bacterial Toxin-Antitoxin Systems' Cross-Interactions-Implications for Practical Use in Medicine and Biotechnology. Toxins (Basel) 2023; 15:380. [PMID: 37368681 DOI: 10.3390/toxins15060380] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 05/30/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023] Open
Abstract
Toxin-antitoxin (TA) systems are widely present in bacterial genomes. They consist of stable toxins and unstable antitoxins that are classified into distinct groups based on their structure and biological activity. TA systems are mostly related to mobile genetic elements and can be easily acquired through horizontal gene transfer. The ubiquity of different homologous and non-homologous TA systems within a single bacterial genome raises questions about their potential cross-interactions. Unspecific cross-talk between toxins and antitoxins of non-cognate modules may unbalance the ratio of the interacting partners and cause an increase in the free toxin level, which can be deleterious to the cell. Moreover, TA systems can be involved in broadly understood molecular networks as transcriptional regulators of other genes' expression or modulators of cellular mRNA stability. In nature, multiple copies of highly similar or identical TA systems are rather infrequent and probably represent a transition stage during evolution to complete insulation or decay of one of them. Nevertheless, several types of cross-interactions have been described in the literature to date. This implies a question of the possibility and consequences of the TA system cross-interactions, especially in the context of the practical application of the TA-based biotechnological and medical strategies, in which such TAs will be used outside their natural context, will be artificially introduced and induced in the new hosts. Thus, in this review, we discuss the prospective challenges of system cross-talks in the safety and effectiveness of TA system usage.
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Affiliation(s)
- Lidia Boss
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, 80-309 Gdańsk, Poland
| | - Barbara Kędzierska
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, 80-309 Gdańsk, Poland
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9
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The DarT/DarG Toxin-Antitoxin ADP-Ribosylation System as a Novel Target for a Rational Design of Innovative Antimicrobial Strategies. Pathogens 2023; 12:pathogens12020240. [PMID: 36839512 PMCID: PMC9967889 DOI: 10.3390/pathogens12020240] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/27/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
The chemical modification of cellular macromolecules by the transfer of ADP-ribose unit(s), known as ADP-ribosylation, is an ancient homeostatic and stress response control system. Highly conserved across the evolution, ADP-ribosyltransferases and ADP-ribosylhydrolases control ADP-ribosylation signalling and cellular responses. In addition to proteins, both prokaryotic and eukaryotic transferases can covalently link ADP-ribosylation to different conformations of nucleic acids, thus highlighting the evolutionary conservation of archaic stress response mechanisms. Here, we report several structural and functional aspects of DNA ADP-ribosylation modification controlled by the prototype DarT and DarG pair, which show ADP-ribosyltransferase and hydrolase activity, respectively. DarT/DarG is a toxin-antitoxin system conserved in many bacterial pathogens, for example in Mycobacterium tuberculosis, which regulates two clinically important processes for human health, namely, growth control and the anti-phage response. The chemical modulation of the DarT/DarG system by selective inhibitors may thus represent an exciting strategy to tackle resistance to current antimicrobial therapies.
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10
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Rack JGM, Ahel I. A Simple Method to Study ADP-Ribosylation Reversal: From Function to Drug Discovery. Methods Mol Biol 2023; 2609:111-132. [PMID: 36515833 DOI: 10.1007/978-1-0716-2891-1_8] [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] [Indexed: 12/15/2022]
Abstract
ADP-ribosylation is an ancient modification of proteins, nucleic acids, and other biomolecules found in all kingdoms of life as well as in certain viruses. The regulation of fundamental (patho)physiological processes by ADP-ribosylation, including the cellular stress response, inflammation, and immune response to bacterial and viral pathogens, has created a strong interest into the study of modification establishment and removal to explore novel therapeutic approaches. Beyond ADP-ribosylation in humans, direct targeting of factors that alter host ADP-ribosylation signaling (e.g., viral macrodomains) or utilize ADP-ribosylation to manipulate host cell behavior (e.g., bacterial toxins) were shown to reduce virulence and disease severity. However, the realization of these therapeutic potentials is thus far hampered by the unavailability of simple, high-throughput methods to study the modification "writers" and "erasers" and screen for novel inhibitors.Here, we describe a scalable method for the measurement of (ADP-ribosyl)hydrolase activity. The assay relies on the conversion of ADP-ribose released from a modified substrate by the (ADP-ribosyl)hydrolase under investigation into AMP by the phosphodiesterase NudT5 into bioluminescence via a commercially available detection assay. Moreover, this method can be utilized to study the role of nudix- or ENPP-type phosphodiesterases in ADP-ribosylation processing and may also be adapted to investigate the activity of (ADP-ribosyl)transferases. Overall, this method is applicable for both basic biochemical characterization and screening of large drug libraries; hence, it is highly adaptable to diverse project needs.
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Affiliation(s)
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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11
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Fang X, Rao K, Wei Z, Cheng J. SOX10
modulated
SMARCA4
dysregulation alleviates
DNA
replication stress in cutaneous melanoma. J Cell Mol Med 2022; 26:5846-5857. [DOI: 10.1111/jcmm.17607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 09/21/2022] [Accepted: 10/15/2022] [Indexed: 12/05/2022] Open
Affiliation(s)
- Xiangjian Fang
- Department of Burns and Plastic Surgery Fujian Medical University Affiliated First Quanzhou Hospital Quanzhou Fujian Province China
| | - Keqiang Rao
- School of Medicine Shanghai Jiao Tong University Shanghai China
| | - Zhiyi Wei
- Department of Burns and Plastic Surgery Fujian Medical University Affiliated First Quanzhou Hospital Quanzhou Fujian Province China
| | - Juntao Cheng
- Department of Burns and Plastic Surgery Fujian Medical University Affiliated First Quanzhou Hospital Quanzhou Fujian Province China
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12
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Dua N, Seshadri A, Badrinarayanan A. DarT-mediated mtDNA damage induces dynamic reorganization and selective segregation of mitochondria. J Cell Biol 2022; 221:213451. [PMID: 36074064 PMCID: PMC9463037 DOI: 10.1083/jcb.202205104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/23/2022] [Accepted: 08/08/2022] [Indexed: 11/22/2022] Open
Abstract
Mitochondria are dynamic organelles that play essential roles in cell growth and survival. Processes of fission and fusion are critical for the distribution, segregation, and maintenance of mitochondria and their genomes (mtDNA). While recent work has revealed the significance of mitochondrial organization for mtDNA maintenance, the impact of mtDNA perturbations on mitochondrial dynamics remains less understood. Here, we develop a tool to induce mitochondria-specific DNA damage using a mitochondrial-targeted base modifying bacterial toxin, DarT. Following damage, we observe dynamic reorganization of mitochondrial networks, likely driven by mitochondrial dysfunction. Changes in the organization are associated with the loss of mtDNA, independent of mitophagy. Unexpectedly, perturbation to exonuclease function of mtDNA replicative polymerase, Mip1, results in rapid loss of mtDNA. Our data suggest that, under damage, partitioning of defective mtDNA and organelle are de-coupled, with emphasis on mitochondrial segregation independent of its DNA. Together, our work underscores the importance of genome maintenance on mitochondrial function, which can act as a modulator of organelle organization and segregation.
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Affiliation(s)
- Nitish Dua
- National Centre for Biological Sciences - Tata Institute of Fundamental Research, Bangalore, Karnataka, India
| | - Akshaya Seshadri
- National Centre for Biological Sciences - Tata Institute of Fundamental Research, Bangalore, Karnataka, India.,SASTRA University, Thanjavur, Tamil Nadu, India
| | - Anjana Badrinarayanan
- National Centre for Biological Sciences - Tata Institute of Fundamental Research, Bangalore, Karnataka, India
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13
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Hloušek-Kasun A, Mikolčević P, Rack JGM, Tromans-Coia C, Schuller M, Jankevicius G, Matković M, Bertoša B, Ahel I, Mikoč A. Streptomyces coelicolor macrodomain hydrolase SCO6735 cleaves thymidine-linked ADP-ribosylation of DNA. Comput Struct Biotechnol J 2022; 20:4337-4350. [PMID: 36051881 PMCID: PMC9411070 DOI: 10.1016/j.csbj.2022.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/01/2022] [Accepted: 08/01/2022] [Indexed: 11/03/2022] Open
Abstract
ADP-ribosylation is an ancient, highly conserved, and reversible covalent modification critical for a variety of endogenous processes in both prokaryotes and eukaryotes. ADP-ribosylation targets proteins, nucleic acids, and small molecules (including antibiotics). ADP-ribosylation signalling involves enzymes that add ADP-ribose to the target molecule, the (ADP-ribosyl)transferases; and those that remove it, the (ADP-ribosyl)hydrolases. Recently, the toxin/antitoxin pair DarT/DarG composed of a DNA ADP-ribosylating toxin, DarT, and (ADP-ribosyl)hydrolase antitoxin, DarG, was described. DarT modifies thymidine in single-stranded DNA in a sequence-specific manner while DarG reverses this modification, thereby rescuing cells from DarT toxicity. We studied the DarG homologue SCO6735 which is highly conserved in all Streptomyces species and known to be associated with antibiotic production in the bacterium S. coelicolor. SCO6735 shares a high structural similarity with the bacterial DarG and human TARG1. Like DarG and TARG1, SCO6735 can also readily reverse thymidine-linked ADP-ribosylation catalysed by DarT in vitro and in cells. SCO6735 active site analysis including molecular dynamic simulations of its complex with ADP-ribosylated thymidine suggests a novel catalytic mechanism of DNA-(ADP-ribose) hydrolysis. Moreover, a comparison of SCO6735 structure with ALC1-like homologues revealed an evolutionarily conserved feature characteristic for this subclass of macrodomain hydrolases.
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Affiliation(s)
| | - Petra Mikolčević
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | | | | | - Marion Schuller
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Gytis Jankevicius
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Marija Matković
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Zagreb, Croatia
| | - Branimir Bertoša
- Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Andreja Mikoč
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
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14
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LeRoux M, Srikant S, Teodoro GIC, Zhang T, Littlehale ML, Doron S, Badiee M, Leung AKL, Sorek R, Laub MT. The DarTG toxin-antitoxin system provides phage defence by ADP-ribosylating viral DNA. Nat Microbiol 2022; 7:1028-1040. [PMID: 35725776 PMCID: PMC9250638 DOI: 10.1038/s41564-022-01153-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 05/18/2022] [Indexed: 01/03/2023]
Abstract
Toxin-antitoxin (TA) systems are broadly distributed, yet poorly conserved, genetic elements whose biological functions are unclear and controversial. Some TA systems may provide bacteria with immunity to infection by their ubiquitous viral predators, bacteriophages. To identify such TA systems, we searched bioinformatically for those frequently encoded near known phage defence genes in bacterial genomes. This search identified homologues of DarTG, a recently discovered family of TA systems whose biological functions and natural activating conditions were unclear. Representatives from two different subfamilies, DarTG1 and DarTG2, strongly protected E. coli MG1655 against different phages. We demonstrate that for each system, infection with either RB69 or T5 phage, respectively, triggers release of the DarT toxin, a DNA ADP-ribosyltransferase, that then modifies viral DNA and prevents replication, thereby blocking the production of mature virions. Further, we isolated phages that have evolved to overcome DarTG defence either through mutations to their DNA polymerase or to an anti-DarT factor, gp61.2, encoded by many T-even phages. Collectively, our results indicate that phage defence may be a common function for TA systems and reveal the mechanism by which DarTG systems inhibit phage infection.
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Affiliation(s)
- Michele LeRoux
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sriram Srikant
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Tong Zhang
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Megan L Littlehale
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Shany Doron
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Mohsen Badiee
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Anthony K L Leung
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
- Department of Molecular Biology and Genetics, Department of Genetic Medicine, Department of Oncology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Rotem Sorek
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Michael T Laub
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA.
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15
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Abstract
Toxin-antitoxin (TA) systems are ubiquitous genetic elements in bacteria that consist of a growth-inhibiting toxin and its cognate antitoxin. These systems are prevalent in bacterial chromosomes, plasmids, and phage genomes, but individual systems are not highly conserved, even among closely related strains. The biological functions of TA systems have been controversial and enigmatic, although a handful of these systems have been shown to defend bacteria against their viral predators, bacteriophages. Additionally, their patterns of conservation-ubiquitous, but rapidly acquired and lost from genomes-as well as the co-occurrence of some TA systems with known phage defense elements are suggestive of a broader role in mediating phage defense. Here, we review the existing evidence for phage defense mediated by TA systems, highlighting how toxins are activated by phage infection and how toxins disrupt phage replication. We also discuss phage-encoded systems that counteract TA systems, underscoring the ongoing coevolutionary battle between bacteria and phage. We anticipate that TA systems will continue to emerge as central players in the innate immunity of bacteria against phage. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Michele LeRoux
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA;
| | - Michael T Laub
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; .,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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16
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Schuller M, Ahel I. Beyond protein modification: the rise of non-canonical ADP-ribosylation. Biochem J 2022; 479:463-477. [PMID: 35175282 PMCID: PMC8883491 DOI: 10.1042/bcj20210280] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/18/2022] [Accepted: 01/21/2022] [Indexed: 12/22/2022]
Abstract
ADP-ribosylation has primarily been known as post-translational modification of proteins. As signalling strategy conserved in all domains of life, it modulates substrate activity, localisation, stability or interactions, thereby regulating a variety of cellular processes and microbial pathogenicity. Yet over the last years, there is increasing evidence of non-canonical forms of ADP-ribosylation that are catalysed by certain members of the ADP-ribosyltransferase family and go beyond traditional protein ADP-ribosylation signalling. New macromolecular targets such as nucleic acids and new ADP-ribose derivatives have been established, notably extending the repertoire of ADP-ribosylation signalling. Based on the physiological relevance known so far, non-canonical ADP-ribosylation deserves its recognition next to the traditional protein ADP-ribosylation modification and which we therefore review in the following.
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Affiliation(s)
- Marion Schuller
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, U.K
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, U.K
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17
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Schaich MA, Van Houten B. Searching for DNA Damage: Insights From Single Molecule Analysis. Front Mol Biosci 2021; 8:772877. [PMID: 34805281 PMCID: PMC8602339 DOI: 10.3389/fmolb.2021.772877] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 10/18/2021] [Indexed: 01/26/2023] Open
Abstract
DNA is under constant threat of damage from a variety of chemical and physical insults, such as ultraviolet rays produced by sunlight and reactive oxygen species produced during respiration or inflammation. Because damaged DNA, if not repaired, can lead to mutations or cell death, multiple DNA repair pathways have evolved to maintain genome stability. Two repair pathways, nucleotide excision repair (NER) and base excision repair (BER), must sift through large segments of nondamaged nucleotides to detect and remove rare base modifications. Many BER and NER proteins share a common base-flipping mechanism for the detection of modified bases. However, the exact mechanisms by which these repair proteins detect their damaged substrates in the context of cellular chromatin remains unclear. The latest generation of single-molecule techniques, including the DNA tightrope assay, atomic force microscopy, and real-time imaging in cells, now allows for nearly direct visualization of the damage search and detection processes. This review describes several mechanistic commonalities for damage detection that were discovered with these techniques, including a combination of 3-dimensional and linear diffusion for surveying damaged sites within long stretches of DNA. We also discuss important findings that DNA repair proteins within and between pathways cooperate to detect damage. Finally, future technical developments and single-molecule studies are described which will contribute to the growing mechanistic understanding of DNA damage detection.
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Affiliation(s)
- Matthew A Schaich
- UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Bennett Van Houten
- UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Molecular Biophysics and Structural Biology Graduate Program, University of Pittsburgh, Pittsburgh, PA, United States
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18
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Tromans-Coia C, Sanchi A, Moeller GK, Timinszky G, Lopes M, Ahel I. TARG1 protects against toxic DNA ADP-ribosylation. Nucleic Acids Res 2021; 49:10477-10492. [PMID: 34508355 PMCID: PMC8501950 DOI: 10.1093/nar/gkab771] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 08/16/2021] [Accepted: 09/09/2021] [Indexed: 01/15/2023] Open
Abstract
ADP-ribosylation is a modification that targets a variety of macromolecules and regulates a diverse array of important cellular processes. ADP-ribosylation is catalysed by ADP-ribosyltransferases and reversed by ADP-ribosylhydrolases. Recently, an ADP-ribosyltransferase toxin termed 'DarT' from bacteria, which is distantly related to human PARPs, was shown to modify thymidine in single-stranded DNA in a sequence specific manner. The antitoxin of DarT is the macrodomain containing ADP-ribosylhydrolase DarG, which shares striking structural homology with the human ADP-ribosylhydrolase TARG1. Here, we show that TARG1, like DarG, can reverse thymidine-linked DNA ADP-ribosylation. We find that TARG1-deficient human cells are extremely sensitive to DNA ADP-ribosylation. Furthermore, we also demonstrate the first detection of reversible ADP-ribosylation on genomic DNA in vivo from human cells. Collectively, our results elucidate the impact of DNA ADP-ribosylation in human cells and provides a molecular toolkit for future studies into this largely unknown facet of ADP-ribosylation.
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Affiliation(s)
- Callum Tromans-Coia
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Andrea Sanchi
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zurich, Switzerland
| | - Giuliana K Moeller
- Department of Physiological Chemistry, Biomedical Center (BMC), Faculty of Medicine, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Gyula Timinszky
- Lendület Laboratory of DNA Damage and Nuclear Dynamics, Institute of Genetics, Biological Research Centre, Eötvös Loránd Research Network (ELKH), 6276 Szeged, Hungary
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, 8057 Zurich, Switzerland
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
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19
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In silico modeling and molecular docking insights of kaempferitrin for colon cancer-related molecular targets. JOURNAL OF SAUDI CHEMICAL SOCIETY 2021. [DOI: 10.1016/j.jscs.2021.101319] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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20
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Groslambert J, Prokhorova E, Ahel I. ADP-ribosylation of DNA and RNA. DNA Repair (Amst) 2021; 105:103144. [PMID: 34116477 PMCID: PMC8385414 DOI: 10.1016/j.dnarep.2021.103144] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/28/2021] [Accepted: 05/31/2021] [Indexed: 12/22/2022]
Abstract
ADP-ribosylation is a chemical modification of macromolecules found across all domains of life and known to regulate a variety of cellular processes. Notably, it has a well-established role in the DNA damage response. While it was historically known as a post-translational modification of proteins, recent studies have shown that nucleic acids can also serve as substrates of reversible ADP-ribosylation. More precisely, ADP-ribosylation of DNA bases, phosphorylated DNA ends and phosphorylated RNA ends have been reported. We will discuss these three types of modification in details. In a variety of bacterial species, including Mycobacterium tuberculosis, ADP-ribosylation of thymidine has emerged as the mode of action of a toxin-antitoxin system named DarTG, with the resultant products perceived as DNA damage by the cell. On the other hand, mammalian DNA damage sensors PARP1, PARP2 and PARP3 were shown to ADP-ribosylate phosphorylated ends of double-stranded DNA in vitro. Additionally, TRPT1 and several PARP enzymes, including PARP10, can add ADP-ribose to the 5'-phosphorylated end of single-stranded RNA in vitro, representing a novel RNA capping mechanism. Together, these discoveries have led to the emergence of a new and exciting research area, namely DNA and RNA ADP-ribosylation, that is likely to have far-reaching implications for the fields of DNA repair, replication and epigenetics.
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Affiliation(s)
- Joséphine Groslambert
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Evgeniia Prokhorova
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom.
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21
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Schuller M, Butler RE, Ariza A, Tromans-Coia C, Jankevicius G, Claridge TDW, Kendall SL, Goh S, Stewart GR, Ahel I. Molecular basis for DarT ADP-ribosylation of a DNA base. Nature 2021; 596:597-602. [PMID: 34408320 DOI: 10.1038/s41586-021-03825-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 07/15/2021] [Indexed: 02/07/2023]
Abstract
ADP-ribosyltransferases use NAD+ to catalyse substrate ADP-ribosylation1, and thereby regulate cellular pathways or contribute to toxin-mediated pathogenicity of bacteria2-4. Reversible ADP-ribosylation has traditionally been considered a protein-specific modification5, but recent in vitro studies have suggested nucleic acids as targets6-9. Here we present evidence that specific, reversible ADP-ribosylation of DNA on thymidine bases occurs in cellulo through the DarT-DarG toxin-antitoxin system, which is found in a variety of bacteria (including global pathogens such as Mycobacterium tuberculosis, enteropathogenic Escherichia coli and Pseudomonas aeruginosa)10. We report the structure of DarT, which identifies this protein as a diverged member of the PARP family. We provide a set of high-resolution structures of this enzyme in ligand-free and pre- and post-reaction states, which reveals a specialized mechanism of catalysis that includes a key active-site arginine that extends the canonical ADP-ribosyltransferase toolkit. Comparison with PARP-HPF1, a well-established DNA repair protein ADP-ribosylation complex, offers insights into how the DarT class of ADP-ribosyltransferases evolved into specific DNA-modifying enzymes. Together, our structural and mechanistic data provide details of this PARP family member and contribute to a fundamental understanding of the ADP-ribosylation of nucleic acids. We also show that thymine-linked ADP-ribose DNA adducts reversed by DarG antitoxin (functioning as a noncanonical DNA repair factor) are used not only for targeted DNA damage to induce toxicity, but also as a signalling strategy for cellular processes. Using M. tuberculosis as an exemplar, we show that DarT-DarG regulates growth by ADP-ribosylation of DNA at the origin of chromosome replication.
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Affiliation(s)
- Marion Schuller
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Rachel E Butler
- Department of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, UK
| | - Antonio Ariza
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | - Gytis Jankevicius
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Biozentrum, University of Basel, Basel, Switzerland
| | - Tim D W Claridge
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Sharon L Kendall
- Centre for Emerging, Endemic and Exotic Disease, Pathology and Population Sciences, The Royal Veterinary College, Hatfield, UK
| | - Shan Goh
- Centre for Emerging, Endemic and Exotic Disease, Pathology and Population Sciences, The Royal Veterinary College, Hatfield, UK
| | - Graham R Stewart
- Department of Microbial Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, UK.
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
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22
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Nonin-Lecomte S, Fermon L, Felden B, Pinel-Marie ML. Bacterial Type I Toxins: Folding and Membrane Interactions. Toxins (Basel) 2021; 13:toxins13070490. [PMID: 34357962 PMCID: PMC8309996 DOI: 10.3390/toxins13070490] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/08/2021] [Accepted: 07/09/2021] [Indexed: 11/16/2022] Open
Abstract
Bacterial type I toxin-antitoxin systems are two-component genetic modules that encode a stable toxic protein whose ectopic overexpression can lead to growth arrest or cell death, and an unstable RNA antitoxin that inhibits toxin translation during growth. These systems are widely spread among bacterial species. Type I antitoxins are cis- or trans-encoded antisense small RNAs that interact with toxin-encoding mRNAs by pairing, thereby inhibiting toxin mRNA translation and/or inducing its degradation. Under environmental stress conditions, the up-regulation of the toxin and/or the antitoxin degradation by specific RNases promote toxin translation. Most type I toxins are small hydrophobic peptides with a predicted α-helical transmembrane domain that induces membrane depolarization and/or permeabilization followed by a decrease of intracellular ATP, leading to plasmid maintenance, growth adaptation to environmental stresses, or persister cell formation. In this review, we describe the current state of the art on the folding and the membrane interactions of these membrane-associated type I toxins from either Gram-negative or Gram-positive bacteria and establish a chronology of their toxic effects on the bacterial cell. This review also includes novel structural results obtained by NMR concerning the sprG1-encoded membrane peptides that belong to the sprG1/SprF1 type I TA system expressed in Staphylococcus aureus and discusses the putative membrane interactions allowing the lysis of competing bacteria and host cells.
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Affiliation(s)
| | - Laurence Fermon
- BRM (Bacterial Regulatory RNAs and Medicine), Inserm, UMR_S 1230, Université de Rennes 1, 35000 Rennes, France; (L.F.); (B.F.)
| | - Brice Felden
- BRM (Bacterial Regulatory RNAs and Medicine), Inserm, UMR_S 1230, Université de Rennes 1, 35000 Rennes, France; (L.F.); (B.F.)
| | - Marie-Laure Pinel-Marie
- BRM (Bacterial Regulatory RNAs and Medicine), Inserm, UMR_S 1230, Université de Rennes 1, 35000 Rennes, France; (L.F.); (B.F.)
- Correspondence:
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23
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Weixler L, Schäringer K, Momoh J, Lüscher B, Feijs KLH, Žaja R. ADP-ribosylation of RNA and DNA: from in vitro characterization to in vivo function. Nucleic Acids Res 2021; 49:3634-3650. [PMID: 33693930 PMCID: PMC8053099 DOI: 10.1093/nar/gkab136] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/11/2021] [Accepted: 02/17/2021] [Indexed: 12/12/2022] Open
Abstract
The functionality of DNA, RNA and proteins is altered dynamically in response to physiological and pathological cues, partly achieved by their modification. While the modification of proteins with ADP-ribose has been well studied, nucleic acids were only recently identified as substrates for ADP-ribosylation by mammalian enzymes. RNA and DNA can be ADP-ribosylated by specific ADP-ribosyltransferases such as PARP1-3, PARP10 and tRNA 2'-phosphotransferase (TRPT1). Evidence suggests that these enzymes display different preferences towards different oligonucleotides. These reactions are reversed by ADP-ribosylhydrolases of the macrodomain and ARH families, such as MACROD1, TARG1, PARG, ARH1 and ARH3. Most findings derive from in vitro experiments using recombinant components, leaving the relevance of this modification in cells unclear. In this Survey and Summary, we provide an overview of the enzymes that ADP-ribosylate nucleic acids, the reversing hydrolases, and the substrates' requirements. Drawing on data available for other organisms, such as pierisin1 from cabbage butterflies and the bacterial toxin-antitoxin system DarT-DarG, we discuss possible functions for nucleic acid ADP-ribosylation in mammals. Hypothesized roles for nucleic acid ADP-ribosylation include functions in DNA damage repair, in antiviral immunity or as non-conventional RNA cap. Lastly, we assess various methods potentially suitable for future studies of nucleic acid ADP-ribosylation.
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Affiliation(s)
- Lisa Weixler
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Pauwelsstrasse 30, Aachen, Germany
| | - Katja Schäringer
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Pauwelsstrasse 30, Aachen, Germany
| | - Jeffrey Momoh
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Pauwelsstrasse 30, Aachen, Germany
| | - Bernhard Lüscher
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Pauwelsstrasse 30, Aachen, Germany
| | - Karla L H Feijs
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Pauwelsstrasse 30, Aachen, Germany
| | - Roko Žaja
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Pauwelsstrasse 30, Aachen, Germany
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24
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Mikolčević P, Hloušek-Kasun A, Ahel I, Mikoč A. ADP-ribosylation systems in bacteria and viruses. Comput Struct Biotechnol J 2021; 19:2366-2383. [PMID: 34025930 PMCID: PMC8120803 DOI: 10.1016/j.csbj.2021.04.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/07/2021] [Accepted: 04/07/2021] [Indexed: 12/30/2022] Open
Abstract
ADP-ribosylation is an ancient posttranslational modification present in all kingdoms of life. The system likely originated in bacteria where it functions in inter- and intra-species conflict, stress response and pathogenicity. It was repeatedly adopted via lateral transfer by eukaryotes, including humans, where it has a pivotal role in epigenetics, DNA-damage repair, apoptosis, and other crucial pathways including the immune response to pathogenic bacteria and viruses. In other words, the same ammunition used by pathogens is adapted by eukaryotes to fight back. While we know quite a lot about the eukaryotic system, expanding rather patchy knowledge on bacterial and viral ADP-ribosylation would give us not only a better understanding of the system as a whole but a fighting advantage in this constant arms race. By writing this review we hope to put into focus the available information and give a perspective on how this system works and can be exploited in the search for therapeutic targets in the future. The relevance of the subject is especially highlighted by the current situation of being amid the world pandemic caused by a virus harbouring and dependent on a representative of such a system.
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Affiliation(s)
- Petra Mikolčević
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | | | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, UK
| | - Andreja Mikoč
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
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25
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Wyżewski Z, Gradowski M, Krysińska M, Dudkiewicz M, Pawłowski K. A novel predicted ADP-ribosyltransferase-like family conserved in eukaryotic evolution. PeerJ 2021; 9:e11051. [PMID: 33854844 PMCID: PMC7955679 DOI: 10.7717/peerj.11051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 02/11/2021] [Indexed: 01/12/2023] Open
Abstract
The presence of many completely uncharacterized proteins, even in well-studied organisms such as humans, seriously hampers full understanding of the functioning of the living cells. ADP-ribosylation is a common post-translational modification of proteins; also nucleic acids and small molecules can be modified by the covalent attachment of ADP-ribose. This modification, important in cellular signalling and infection processes, is usually executed by enzymes from the large superfamily of ADP-ribosyltransferases (ARTs). Here, using bioinformatics approaches, we identify a novel putative ADP-ribosyltransferase family, conserved in eukaryotic evolution, with a divergent active site. The hallmark of these proteins is the ART domain nestled between flanking leucine-rich repeat (LRR) domains. LRRs are typically involved in innate immune surveillance. The novel family appears as putative novel ADP-ribosylation-related actors, most likely pseudoenzymes. Sequence divergence and lack of clearly detectable “classical” ART active site suggests the novel domains are pseudoARTs, yet atypical ART activity, or alternative enzymatic activity cannot be excluded. We propose that this family, including its human member LRRC9, may be involved in an ancient defense mechanism, with analogies to the innate immune system, and coupling pathogen detection to ADP-ribosyltransfer or other signalling mechanisms.
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Affiliation(s)
- Zbigniew Wyżewski
- Institute of Biological Sciences, Cardinal Stefan Wyszynski University in Warsaw, Warszawa, Poland
| | - Marcin Gradowski
- Department of Biochemistry and Microbiology, Warsaw University of Life Sciences - SGGW, Warszawa, Poland
| | - Marianna Krysińska
- Department of Biochemistry and Microbiology, Warsaw University of Life Sciences - SGGW, Warszawa, Poland
| | - Małgorzata Dudkiewicz
- Department of Biochemistry and Microbiology, Warsaw University of Life Sciences - SGGW, Warszawa, Poland
| | - Krzysztof Pawłowski
- Department of Biochemistry and Microbiology, Warsaw University of Life Sciences - SGGW, Warszawa, Poland.,Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Translational Medicine, Lund University, Lund, Sweden
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26
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Bacterial phenotypic heterogeneity in DNA repair and mutagenesis. Biochem Soc Trans 2021; 48:451-462. [PMID: 32196548 PMCID: PMC7200632 DOI: 10.1042/bst20190364] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 02/26/2020] [Accepted: 02/28/2020] [Indexed: 02/06/2023]
Abstract
Genetically identical cells frequently exhibit striking heterogeneity in various phenotypic traits such as their morphology, growth rate, or gene expression. Such non-genetic diversity can help clonal bacterial populations overcome transient environmental challenges without compromising genome stability, while genetic change is required for long-term heritable adaptation. At the heart of the balance between genome stability and plasticity are the DNA repair pathways that shield DNA from lesions and reverse errors arising from the imperfect DNA replication machinery. In principle, phenotypic heterogeneity in the expression and activity of DNA repair pathways can modulate mutation rates in single cells and thus be a source of heritable genetic diversity, effectively reversing the genotype-to-phenotype dogma. Long-standing evidence for mutation rate heterogeneity comes from genetics experiments on cell populations, which are now complemented by direct measurements on individual living cells. These measurements are increasingly performed using fluorescence microscopy with a temporal and spatial resolution that enables localising, tracking, and counting proteins with single-molecule sensitivity. In this review, we discuss which molecular processes lead to phenotypic heterogeneity in DNA repair and consider the potential consequences on genome stability and dynamics in bacteria. We further inspect these concepts in the context of DNA damage and mutation induced by antibiotics.
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27
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Vatta M, Lyons B, Heney KA, Lidster T, Merrill AR. Mapping the DNA-Binding Motif of Scabin Toxin, a Guanine Modifying Enzyme from Streptomyces scabies. Toxins (Basel) 2021; 13:toxins13010055. [PMID: 33450958 PMCID: PMC7828395 DOI: 10.3390/toxins13010055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/23/2020] [Accepted: 01/09/2021] [Indexed: 11/16/2022] Open
Abstract
Scabin is a mono-ADP-ribosyltransferase toxin/enzyme and possible virulence factor produced by the agriculture pathogen, Streptomyces scabies. Recently, molecular dynamic approaches and MD simulations revealed its interaction with both NAD+ and DNA substrates. An Essential Dynamics Analysis identified a crab-claw-like mechanism, including coupled changes in the exposed motifs, and the Rβ1-RLa-NLc-STTβ2-WPN-WARTT-(QxE)ARTT sequence motif was proposed as a catalytic signature of the Pierisin family of DNA-acting toxins. A new fluorescence assay was devised to measure the kinetics for both RNA and DNA substrates. Several protein variants were prepared to probe the Scabin-NAD-DNA molecular model and to reveal the reaction mechanism for the transfer of ADP-ribose to the guanine base in the DNA substrate. The results revealed that there are several lysine and arginine residues in Scabin that are important for binding the DNA substrate; also, key residues such as Asn110 in the mechanism of ADP-ribose transfer to the guanine base were identified. The DNA-binding residues are shared with ScARP from Streptomyces coelicolor but are not conserved with Pierisin-1, suggesting that the modification of guanine bases by ADP-ribosyltransferases is divergent even in the Pierisin family.
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Affiliation(s)
- Maritza Vatta
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada;
| | - Bronwyn Lyons
- Department of Biochemistry and Molecular Biology and Center for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada;
| | - Kayla A. Heney
- Department of Biochemistry, McGill University, Montreal, QC H3G 1Y6, Canada;
| | - Taylor Lidster
- Department of Biological Sciences, Brock University, St. Catherines, ON L2S 3A1, Canada;
| | - A. Rod Merrill
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada;
- Correspondence: ; Fax: +1-519-837-1802
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Yoshida T, Tsuge H. Common Mechanism for Target Specificity of Protein- and DNA-Targeting ADP-Ribosyltransferases. Toxins (Basel) 2021; 13:toxins13010040. [PMID: 33430384 PMCID: PMC7827354 DOI: 10.3390/toxins13010040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 01/01/2021] [Accepted: 01/03/2021] [Indexed: 12/14/2022] Open
Abstract
Many bacterial pathogens utilize ADP-ribosyltransferases (ARTs) as virulence factors. The critical aspect of ARTs is their target specificity. Each individual ART modifies a specific residue of its substrates, which could be proteins, DNA, or antibiotics. However, the mechanism underlying this specificity is poorly understood. Here, we review the substrate recognition mechanism and target residue specificity based on the available complex structures of ARTs and their substrates. We show that there are common mechanisms of target residue specificity among protein- and DNA-targeting ARTs.
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Affiliation(s)
- Toru Yoshida
- Faculty of Science, Japan Women’s University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo 112-8681, Japan;
| | - Hideaki Tsuge
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto 603-8555, Japan
- Institute for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto 603-8555, Japan
- Center for Molecular Research in Infectious Diseases, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto 603-8555, Japan
- Correspondence: ; Tel.: +81-75-705-3117
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29
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Munnur D, Ahel I. Detecting ADP-Ribosylation in RNA. Methods Mol Biol 2021; 2298:231-243. [PMID: 34085249 DOI: 10.1007/978-1-0716-1374-0_15] [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] [Indexed: 02/11/2024]
Abstract
ADP-ribosylation is a widespread reversible chemical modification of macromolecular targets. Protein ADP-ribosylation has been widely studied and plays a vital role in the regulation of several biological processes. In recent years there has been increasing interest in alternative ADP-ribosylation targets such as nucleic acids-DNA and RNA. Here we report different methods to detect ADP-ribosylation of RNA substrates.
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Affiliation(s)
- Deeksha Munnur
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
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30
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Zhang SP, Feng HZ, Wang Q, Kempher ML, Quan SW, Tao X, Niu S, Wang Y, Feng HY, He YX. Bacterial type II toxin-antitoxin systems acting through post-translational modifications. Comput Struct Biotechnol J 2020; 19:86-93. [PMID: 33384857 PMCID: PMC7758455 DOI: 10.1016/j.csbj.2020.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/30/2020] [Accepted: 12/02/2020] [Indexed: 11/17/2022] Open
Abstract
The post-translational modification (PTM) serves as an important molecular switch mechanism to modulate diverse biological functions in response to specific cues. Though more commonly found in eukaryotic cells, many PTMs have been identified and characterized in bacteria over the past decade, highlighting the importance of PTMs in regulating bacterial physiology. Several bacterial PTM enzymes have been characterized to function as the toxin component of type II TA systems, which consist of a toxin that inhibits cell growth and an antitoxin that protects the cell from poisoning by the toxin. While TA systems can be classified into seven types based on nature of the antitoxin and its activity, type II TA systems are perhaps the most studied among the different TA types and widely distributed in eubacteria and archaea. The type II toxins possessing PTM activities typically modify various cellular targets mostly associated with protein translation and DNA replication. This review mainly focuses on the enzymatic activities, target specificities, antitoxin neutralizing mechanisms of the different families of PTM toxins. We also proposed that TA systems can be conceptually viewed as molecular switches where the 'on' and 'off' state of the system is tightly controlled by antitoxins and discussed the perspective on toxins having other physiologically roles apart from growth inhibition by acting on the nonessential cellular targets.
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Affiliation(s)
- Si-Ping Zhang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Han-Zhong Feng
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Qian Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Megan L Kempher
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Shuo-Wei Quan
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Xuanyu Tao
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Shaomin Niu
- Institute of Urology, Lanzhou University Second Hospital, Key Laboratory of Urological Diseases in Gansu Province, Gansu Nephro-Urological Clinical Center, Lanzhou, PR China
| | - Yong Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Hu-Yuan Feng
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
| | - Yong-Xing He
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China
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Krishnan A, Burroughs AM, Iyer LM, Aravind L. Comprehensive classification of ABC ATPases and their functional radiation in nucleoprotein dynamics and biological conflict systems. Nucleic Acids Res 2020; 48:10045-10075. [PMID: 32894288 DOI: 10.1093/nar/gkaa726] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/17/2020] [Accepted: 08/20/2020] [Indexed: 12/13/2022] Open
Abstract
ABC ATPases form one of the largest clades of P-loop NTPase fold enzymes that catalyze ATP-hydrolysis and utilize its free energy for a staggering range of functions from transport to nucleoprotein dynamics. Using sensitive sequence and structure analysis with comparative genomics, for the first time we provide a comprehensive classification of the ABC ATPase superfamily. ABC ATPases developed structural hallmarks that unambiguously distinguish them from other P-loop NTPases such as an alternative to arginine-finger-based catalysis. At least five and up to eight distinct clades of ABC ATPases are reconstructed as being present in the last universal common ancestor. They underwent distinct phases of structural innovation with the emergence of inserts constituting conserved binding interfaces for proteins or nucleic acids and the adoption of a unique dimeric toroidal configuration for DNA-threading. Specifically, several clades have also extensively radiated in counter-invader conflict systems where they serve as nodal nucleotide-dependent sensory and energetic components regulating a diversity of effectors (including some previously unrecognized) acting independently or together with restriction-modification systems. We present a unified mechanism for ABC ATPase function across disparate systems like RNA editing, translation, metabolism, DNA repair, and biological conflicts, and some unexpected recruitments, such as MutS ATPases in secondary metabolism.
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Affiliation(s)
- Arunkumar Krishnan
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - A Maxwell Burroughs
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Lakshminarayan M Iyer
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - L Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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Zaveri A, Wang R, Botella L, Sharma R, Zhu L, Wallach JB, Song N, Jansen RS, Rhee KY, Ehrt S, Schnappinger D. Depletion of the DarG antitoxin in Mycobacterium tuberculosis triggers the DNA-damage response and leads to cell death. Mol Microbiol 2020; 114:641-652. [PMID: 32634279 PMCID: PMC7689832 DOI: 10.1111/mmi.14571] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/28/2020] [Accepted: 07/01/2020] [Indexed: 01/01/2023]
Abstract
Of the ~80 putative toxin-antitoxin (TA) modules encoded by the bacterial pathogen Mycobacterium tuberculosis (Mtb), three contain antitoxins essential for bacterial viability. One of these, Rv0060 (DNA ADP-ribosyl glycohydrolase, DarGMtb ), functions along with its cognate toxin Rv0059 (DNA ADP-ribosyl transferase, DarTMtb ), to mediate reversible DNA ADP-ribosylation (Jankevicius et al., 2016). We demonstrate that DarTMtb -DarGMtb form a functional TA pair and essentiality of darGMtb is dependent on the presence of darTMtb , but simultaneous deletion of both darTMtb -darGMtb does not alter viability of Mtb in vitro or in mice. The antitoxin, DarGMtb , forms a cytosolic complex with DNA-repair proteins that assembles independently of either DarTMtb or interaction with DNA. Depletion of DarGMtb alone is bactericidal, a phenotype that is rescued by expression of an orthologous antitoxin, DarGTaq , from Thermus aquaticus. Partial depletion of DarGMtb triggers a DNA-damage response and sensitizes Mtb to drugs targeting DNA metabolism and respiration. Induction of the DNA-damage response is essential for Mtb to survive partial DarGMtb -depletion and leads to a hypermutable phenotype.
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Affiliation(s)
- Anisha Zaveri
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Ruojun Wang
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Laure Botella
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Ritu Sharma
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Linnan Zhu
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Joshua B Wallach
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Naomi Song
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Robert S Jansen
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Kyu Y Rhee
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Sabine Ehrt
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
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33
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Cross-Regulations between Bacterial Toxin-Antitoxin Systems: Evidence of an Interconnected Regulatory Network? Trends Microbiol 2020; 28:851-866. [PMID: 32540313 DOI: 10.1016/j.tim.2020.05.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 12/31/2022]
Abstract
Toxin-antitoxin (TA) systems are ubiquitous among bacteria and include stable toxins whose toxicity can be counteracted by RNA or protein antitoxins. They are involved in multiple functions that range from stability maintenance for mobile genetic elements to stress adaptation. Bacterial chromosomes frequently have multiple homologues of TA system loci, and it is unclear why there are so many of them. In this review we focus on cross-regulations between TA systems, which occur between both homologous and nonhomologous systems, from similar or distinct types, whether encoded from plasmids or chromosomes. In addition to being able to modulate RNA expression levels, cross-regulations between these systems can also influence their toxicity. This suggests the idea that they are involved in an interconnected regulatory network.
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