1
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Tang N, Wen W, Liu Z, Xiong X, Wu Y. HELQ as a DNA helicase: Its novel role in normal cell function and tumorigenesis (Review). Oncol Rep 2023; 50:220. [PMID: 37921071 PMCID: PMC10652244 DOI: 10.3892/or.2023.8657] [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: 02/22/2023] [Accepted: 08/08/2023] [Indexed: 11/04/2023] Open
Abstract
Helicase POLQ‑like (HELQ or Hel308), is a highly conserved, 3'‑5' superfamily II DNA helicase that contributes to diverse DNA processes, including DNA repair, unwinding, and strand annealing. HELQ deficiency leads to subfertility, due to its critical role in germ cell stability. In addition, the abnormal expression of HELQ has been observed in multiple tumors and a number of molecular pathways, including the nucleotide excision repair, checkpoint kinase 1‑DNA repair protein RAD51 homolog 1 and ATM/ATR pathways, have been shown to be involved in HELQ. In the present review, the structure and characteristics of HELQ, as well as its major functions in DNA processing, were described. Molecular mechanisms involving HELQ in the context of tumorigenesis were also described. It was deduced that HELQ biology warrants investigation, and that its critical roles in the regulation of various DNA processes and participation in tumorigenesis are clinically relevant.
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Affiliation(s)
- Nan Tang
- Department of Traditional Chinese Medicine, Guangzhou Red Cross Hospital of Jinan University, Guangzhou, Guangdong 510220, P.R. China
| | - Weilun Wen
- Department of Traditional Chinese Medicine, Guangzhou Red Cross Hospital of Jinan University, Guangzhou, Guangdong 510220, P.R. China
| | - Zhihe Liu
- Guangzhou Institute of Traumatic Surgery, Guangzhou Red Cross Hospital of Jinan University, Guangzhou, Guangdong 510220, P.R. China
| | - Xifeng Xiong
- Guangzhou Institute of Traumatic Surgery, Guangzhou Red Cross Hospital of Jinan University, Guangzhou, Guangdong 510220, P.R. China
| | - Yanhua Wu
- Department of Traditional Chinese Medicine, Guangzhou Red Cross Hospital of Jinan University, Guangzhou, Guangdong 510220, P.R. China
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2
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Lever R, Simmons E, Gamble-Milner R, Buckley R, Harrison C, Parkes A, Mitchell L, Gausden J, Škulj S, Bertoša B, Bolt E, Allers T. Archaeal Hel308 suppresses recombination through a catalytic switch that controls DNA annealing. Nucleic Acids Res 2023; 51:8563-8574. [PMID: 37409572 PMCID: PMC10484726 DOI: 10.1093/nar/gkad572] [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: 03/25/2023] [Revised: 06/14/2023] [Accepted: 06/23/2023] [Indexed: 07/07/2023] Open
Abstract
Hel308 helicases promote genome stability in archaea and are conserved in metazoans, where they are known as HELQ. Their helicase mechanism is well characterised, but it is unclear how they specifically contribute to genome stability in archaea. We show here that a highly conserved motif of Hel308/HELQ helicases (motif IVa, F/YHHAGL) modulates both DNA unwinding and a newly identified strand annealing function of archaeal Hel308. A single amino acid substitution in motif IVa results in hyper-active DNA helicase and annealase activities of purified Hel308 in vitro. All-atom molecular dynamics simulations using Hel308 crystal structures provided a molecular basis for these differences between mutant and wild type Hel308. In archaeal cells, the same mutation results in 160000-fold increased recombination, exclusively as gene conversion (non-crossover) events. However, crossover recombination is unaffected by the motif IVa mutation, as is cell viability or DNA damage sensitivity. By contrast, cells lacking Hel308 show impaired growth, increased sensitivity to DNA cross-linking agents, and only moderately increased recombination. Our data reveal that archaeal Hel308 suppresses recombination and promotes DNA repair, and that motif IVa in the RecA2 domain acts as a catalytic switch to modulate the separable recombination and repair activities of Hel308.
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Affiliation(s)
- Rebecca J Lever
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Emily Simmons
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | | | - Ryan J Buckley
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Catherine Harrison
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Ashley J Parkes
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Laura Mitchell
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Jacob A Gausden
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Sanja Škulj
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, HR-10000 Zagreb, Croatia
| | - Branimir Bertoša
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, HR-10000 Zagreb, Croatia
| | - Edward L Bolt
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Thorsten Allers
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
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3
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Buckley RJ, Lou‐Hing A, Hanson KM, Ahmed NR, Cooper CDO, Bolt EL. Escherichia coli DNA repair helicase Lhr is also a uracil-DNA glycosylase. Mol Microbiol 2023; 120:298-306. [PMID: 37452011 PMCID: PMC10953399 DOI: 10.1111/mmi.15123] [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: 01/16/2023] [Revised: 06/24/2023] [Accepted: 06/27/2023] [Indexed: 07/18/2023]
Abstract
DNA glycosylases protect genetic fidelity during DNA replication by removing potentially mutagenic chemically damaged DNA bases. Bacterial Lhr proteins are well-characterized DNA repair helicases that are fused to additional 600-700 amino acids of unknown function, but with structural homology to SecB chaperones and AlkZ DNA glycosylases. Here, we identify that Escherichia coli Lhr is a uracil-DNA glycosylase (UDG) that depends on an active site aspartic acid residue. We show that the Lhr DNA helicase activity is functionally independent of the UDG activity, but that the helicase domains are required for fully active UDG activity. Consistent with UDG activity, deletion of lhr from the E. coli chromosome sensitized cells to oxidative stress that triggers cytosine deamination to uracil. The ability of Lhr to translocate single-stranded DNA and remove uracil bases suggests a surveillance role to seek and remove potentially mutagenic base changes during replication stress.
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Affiliation(s)
| | - Anna Lou‐Hing
- School of Life SciencesUniversity of NottinghamNottinghamUK
| | - Karl M. Hanson
- School of Biological and Geographical Sciences, School of Applied SciencesUniversity of HuddersfieldHuddersfieldUK
| | - Nadia R. Ahmed
- School of Biological and Geographical Sciences, School of Applied SciencesUniversity of HuddersfieldHuddersfieldUK
| | - Christopher D. O. Cooper
- School of Biological and Geographical Sciences, School of Applied SciencesUniversity of HuddersfieldHuddersfieldUK
- CHARM Therapeutics LtdB900 Babraham Research CampusCambridgeUK
| | - Edward L. Bolt
- School of Life SciencesUniversity of NottinghamNottinghamUK
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4
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Marshall CJ, Qayyum MZ, Walker JE, Murakami KS, Santangelo TJ. The structure and activities of the archaeal transcription termination factor Eta detail vulnerabilities of the transcription elongation complex. Proc Natl Acad Sci U S A 2022; 119:e2207581119. [PMID: 35917344 PMCID: PMC9371683 DOI: 10.1073/pnas.2207581119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 06/22/2022] [Indexed: 02/04/2023] Open
Abstract
Transcription must be properly regulated to ensure dynamic gene expression underlying growth, development, and response to environmental cues. Regulation is imposed throughout the transcription cycle, and while many efforts have detailed the regulation of transcription initiation and early elongation, the termination phase of transcription also plays critical roles in regulating gene expression. Transcription termination can be driven by only a few proteins in each domain of life. Detailing the mechanism(s) employed provides insight into the vulnerabilities of transcription elongation complexes (TECs) that permit regulated termination to control expression of many genes and operons. Here, we describe the biochemical activities and crystal structure of the superfamily 2 helicase Eta, one of two known factors capable of disrupting archaeal transcription elongation complexes. Eta retains a twin-translocase core domain common to all superfamily 2 helicases and a well-conserved C terminus wherein individual amino acid substitutions can critically abrogate termination activities. Eta variants that perturb ATPase, helicase, single-stranded DNA and double-stranded DNA translocase and termination activities identify key regions of the C terminus of Eta that, when combined with modeling Eta-TEC interactions, provide a structural model of Eta-mediated termination guided in part by structures of Mfd and the bacterial TEC. The susceptibility of TECs to disruption by termination factors that target the upstream surface of RNA polymerase and potentially drive termination through forward translocation and allosteric mechanisms that favor opening of the clamp to release the encapsulated nucleic acids emerges as a common feature of transcription termination mechanisms.
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Affiliation(s)
- Craig J. Marshall
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - M. Zuhaib Qayyum
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | - Julie E. Walker
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - Katsuhiko S. Murakami
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | - Thomas J. Santangelo
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
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Modelling single-molecule kinetics of helicase translocation using high-resolution nanopore tweezers (SPRNT). Essays Biochem 2021; 65:109-127. [PMID: 33491732 DOI: 10.1042/ebc20200027] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/23/2020] [Accepted: 11/30/2020] [Indexed: 12/16/2022]
Abstract
Single-molecule picometer resolution nanopore tweezers (SPRNT) is a technique for monitoring the motion of individual enzymes along a nucleic acid template at unprecedented spatiotemporal resolution. We review the development of SPRNT and the application of single-molecule kinetics theory to SPRNT data to develop a detailed model of helicase motion along a single-stranded DNA substrate. In this review, we present three examples of questions SPRNT can answer in the context of the Superfamily 2 helicase Hel308. With Hel308, SPRNT's spatiotemporal resolution enables resolution of two distinct enzymatic substates, one which is dependent upon ATP concentration and one which is ATP independent. By analyzing dwell-time distributions and helicase back-stepping, we show, in detail, how SPRNT can be used to determine the nature of these observed steps. We use dwell-time distributions to discern between three different possible models of helicase backstepping. We conclude by using SPRNT's ability to discern an enzyme's nucleotide-specific location along a DNA strand to understand the nature of sequence-specific enzyme kinetics and show that the sequence within the helicase itself affects both step dwell-time and backstepping probability while translocating on single-stranded DNA.
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Mechanistic insights into Lhr helicase function in DNA repair. Biochem J 2021; 477:2935-2947. [PMID: 32706021 PMCID: PMC7437997 DOI: 10.1042/bcj20200379] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/23/2020] [Accepted: 07/23/2020] [Indexed: 12/16/2022]
Abstract
The DNA helicase Large helicase-related (Lhr) is present throughout archaea, including in the Asgard and Nanoarchaea, and has homologues in bacteria and eukaryotes. It is thought to function in DNA repair but in a context that is not known. Our data show that archaeal Lhr preferentially targets DNA replication fork structures. In a genetic assay, expression of archaeal Lhr gave a phenotype identical to the replication-coupled DNA repair enzymes Hel308 and RecQ. Purified archaeal Lhr preferentially unwound model forked DNA substrates compared with DNA duplexes, flaps and Holliday junctions, and unwound them with directionality. Single-molecule FRET measurements showed that binding of Lhr to a DNA fork causes ATP-independent distortion and base-pair melting at, or close to, the fork branchpoint. ATP-dependent directional translocation of Lhr resulted in fork DNA unwinding through the ‘parental’ DNA strands. Interaction of Lhr with replication forks in vivo and in vitro suggests that it contributes to DNA repair at stalled or broken DNA replication.
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Marshall CJ, Santangelo TJ. Archaeal DNA Repair Mechanisms. Biomolecules 2020; 10:E1472. [PMID: 33113933 PMCID: PMC7690668 DOI: 10.3390/biom10111472] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 12/29/2022] Open
Abstract
Archaea often thrive in environmental extremes, enduring levels of heat, pressure, salinity, pH, and radiation that prove intolerable to most life. Many environmental extremes raise the propensity for DNA damaging events and thus, impact DNA stability, placing greater reliance on molecular mechanisms that recognize DNA damage and initiate accurate repair. Archaea can presumably prosper in harsh and DNA-damaging environments in part due to robust DNA repair pathways but surprisingly, no DNA repair pathways unique to Archaea have been described. Here, we review the most recent advances in our understanding of archaeal DNA repair. We summarize DNA damage types and their consequences, their recognition by host enzymes, and how the collective activities of many DNA repair pathways maintain archaeal genomic integrity.
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Affiliation(s)
| | - Thomas J. Santangelo
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA;
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8
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Leal AZ, Schwebs M, Briggs E, Weisert N, Reis H, Lemgruber L, Luko K, Wilkes J, Butter F, McCulloch R, Janzen CJ. Genome maintenance functions of a putative Trypanosoma brucei translesion DNA polymerase include telomere association and a role in antigenic variation. Nucleic Acids Res 2020; 48:9660-9680. [PMID: 32890403 PMCID: PMC7515707 DOI: 10.1093/nar/gkaa686] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 08/03/2020] [Accepted: 09/03/2020] [Indexed: 12/17/2022] Open
Abstract
Maintenance of genome integrity is critical to guarantee transfer of an intact genome from parent to offspring during cell division. DNA polymerases (Pols) provide roles in both replication of the genome and the repair of a wide range of lesions. Amongst replicative DNA Pols, translesion DNA Pols play a particular role: replication to bypass DNA damage. All cells express a range of translesion Pols, but little work has examined their function in parasites, including whether the enzymes might contribute to host-parasite interactions. Here, we describe a dual function of one putative translesion Pol in African trypanosomes, which we now name TbPolIE. Previously, we demonstrated that TbPolIE is associated with telomeric sequences and here we show that RNAi-mediated depletion of TbPolIE transcripts results in slowed growth, altered DNA content, changes in cell morphology, and increased sensitivity to DNA damaging agents. We also show that TbPolIE displays pronounced localization at the nuclear periphery, and that its depletion leads to chromosome segregation defects and increased levels of endogenous DNA damage. Finally, we demonstrate that TbPolIE depletion leads to deregulation of telomeric variant surface glycoprotein genes, linking the function of this putative translesion DNA polymerase to host immune evasion by antigenic variation.
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Affiliation(s)
- Andrea Zurita Leal
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Marie Schwebs
- Department of Cell & Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Emma Briggs
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Nadine Weisert
- Department of Cell & Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Helena Reis
- Department of Cell & Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Leandro Lemgruber
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Katarina Luko
- Quantitative Proteomics, Institute of Molecular Biology (IMB), Mainz, Germany
| | - Jonathan Wilkes
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Falk Butter
- Quantitative Proteomics, Institute of Molecular Biology (IMB), Mainz, Germany
| | - Richard McCulloch
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Christian J Janzen
- Department of Cell & Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
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9
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Craig JM, Laszlo AH, Nova IC, Brinkerhoff H, Noakes MT, Baker KS, Bowman JL, Higinbotham HR, Mount JW, Gundlach JH. Determining the effects of DNA sequence on Hel308 helicase translocation along single-stranded DNA using nanopore tweezers. Nucleic Acids Res 2019; 47:2506-2513. [PMID: 30649515 PMCID: PMC6412116 DOI: 10.1093/nar/gkz004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 12/30/2018] [Accepted: 01/03/2019] [Indexed: 12/22/2022] Open
Abstract
Motor enzymes that process nucleic-acid substrates play vital roles in all aspects of genome replication, expression, and repair. The DNA and RNA nucleobases are known to affect the kinetics of these systems in biologically meaningful ways. Recently, it was shown that DNA bases control the translocation speed of helicases on single-stranded DNA, however the cause of these effects remains unclear. We use single-molecule picometer-resolution nanopore tweezers (SPRNT) to measure the kinetics of translocation along single-stranded DNA by the helicase Hel308 from Thermococcus gammatolerans. SPRNT can measure enzyme steps with subangstrom resolution on millisecond timescales while simultaneously measuring the absolute position of the enzyme along the DNA substrate. Previous experiments with SPRNT revealed the presence of two distinct substates within the Hel308 ATP hydrolysis cycle, one [ATP]-dependent and the other [ATP]-independent. Here, we analyze in-depth the apparent sequence dependent behavior of the [ATP]-independent step. We find that DNA bases at two sites within Hel308 control sequence-specific kinetics of the [ATP]-independent step. We suggest mechanisms for the observed sequence-specific translocation kinetics. Similar SPRNT measurements and methods can be applied to other nucleic-acid-processing motor enzymes.
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Affiliation(s)
- Jonathan M Craig
- Department of Physics, University of Washington, Seattle, WA 98105, USA
| | - Andrew H Laszlo
- Department of Physics, University of Washington, Seattle, WA 98105, USA
| | - Ian C Nova
- Department of Physics, University of Washington, Seattle, WA 98105, USA
| | - Henry Brinkerhoff
- Department of Physics, University of Washington, Seattle, WA 98105, USA
| | - Matthew T Noakes
- Department of Physics, University of Washington, Seattle, WA 98105, USA
| | - Katherine S Baker
- Department of Physics, University of Washington, Seattle, WA 98105, USA
| | - Jasmine L Bowman
- Department of Physics, University of Washington, Seattle, WA 98105, USA
| | | | - Jonathan W Mount
- Department of Physics, University of Washington, Seattle, WA 98105, USA
| | - Jens H Gundlach
- Department of Physics, University of Washington, Seattle, WA 98105, USA
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White MF, Allers T. DNA repair in the archaea-an emerging picture. FEMS Microbiol Rev 2018; 42:514-526. [PMID: 29741625 DOI: 10.1093/femsre/fuy020] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/02/2018] [Indexed: 12/12/2022] Open
Abstract
There has long been a fascination in the DNA repair pathways of archaea, for two main reasons. Firstly, many archaea inhabit extreme environments where the rate of physical damage to DNA is accelerated. These archaea might reasonably be expected to have particularly robust or novel DNA repair pathways to cope with this. Secondly, the archaea have long been understood to be a lineage distinct from the bacteria, and to share a close relationship with the eukarya, particularly in their information processing systems. Recent discoveries suggest the eukarya arose from within the archaeal domain, and in particular from lineages related to the TACK superphylum and Lokiarchaea. Thus, archaeal DNA repair proteins and pathways can represent a useful model system. This review focuses on recent advances in our understanding of archaeal DNA repair processes including base excision repair, nucleotide excision repair, mismatch repair and double-strand break repair. These advances are discussed in the context of the emerging picture of the evolution and relationship of the three domains of life.
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Affiliation(s)
- Malcolm F White
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, Fife KY16 9ST, UK
| | - Thorsten Allers
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
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