1
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Přibylová A, Fischer L. How to use CRISPR/Cas9 in plants: from target site selection to DNA repair. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:5325-5343. [PMID: 38648173 PMCID: PMC11389839 DOI: 10.1093/jxb/erae147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 04/21/2024] [Indexed: 04/25/2024]
Abstract
A tool for precise, target-specific, efficient, and affordable genome editing is a dream for many researchers, from those who conduct basic research to those who use it for applied research. Since 2012, we have tool that almost fulfils such requirements; it is based on clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) systems. However, even CRISPR/Cas has limitations and obstacles that might surprise its users. In this review, we focus on the most frequently used variant, CRISPR/Cas9 from Streptococcus pyogenes, and highlight key factors affecting its mutagenesis outcomes: (i) factors affecting the CRISPR/Cas9 activity, such as the effect of the target sequence, chromatin state, or Cas9 variant, and how long it remains in place after cleavage; and (ii) factors affecting the follow-up DNA repair mechanisms including mostly the cell type and cell cycle phase, but also, for example, the type of DNA ends produced by Cas9 cleavage (blunt/staggered). Moreover, we note some differences between using CRISPR/Cas9 in plants, yeasts, and animals, as knowledge from individual kingdoms is not fully transferable. Awareness of these factors can increase the likelihood of achieving the expected results of plant genome editing, for which we provide detailed guidelines.
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Affiliation(s)
- Adéla Přibylová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 12800, Prague 2, Czech Republic
| | - Lukáš Fischer
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 12800, Prague 2, Czech Republic
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2
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Blanch JR, Krishnamurthy M, McVey M. A non-tethering role for the Drosophila Pol θ linker domain in promoting damage resolution. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.27.609911. [PMID: 39253446 PMCID: PMC11383001 DOI: 10.1101/2024.08.27.609911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
DNA polymerase theta ( Pol θ ) is an error-prone translesion polymerase that becomes crucial for DNA double-strand break repair when cells are deficient in homologous recombination or non-homologous end joining. In some organisms, Pol θ also promotes tolerance of DNA interstrand crosslinks. Due to its importance in DNA damage tolerance, Pol θ is an emerging target for treatment of cancer and disease. Prior work has characterized the functions of the Pol θ helicase-like and polymerase domains, but the roles of the linker domain are largely unknown. Here, we show that the Drosophila melanogaster Pol θ linker domain promotes egg development and is required for tolerance of DNA double-strand breaks and interstrand crosslinks. While a linker domain with scrambled amino acid residues is sufficient for DNA repair, replacement of the linker with part of the Homo sapiens Pol θ linker or a disordered region from the FUS RNA-binding protein does not restore function. These results demonstrate that the linker domain is not simply a random tether between the helicase-like and polymerase domains. Furthermore, they suggest that intrinsic amino acid residue properties, rather than protein interaction motifs, are more critical for Pol θ linker functions in DNA repair.
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Affiliation(s)
- Justin R Blanch
- Department of Biology, Tufts University, Medford, Massachusetts, 02155, United States of America
| | - Manan Krishnamurthy
- Department of Biology, Tufts University, Medford, Massachusetts, 02155, United States of America
- Icahn School of Medicine at Mount Sinai, New York City, New York, 10029, United States of America
| | - Mitch McVey
- Department of Biology, Tufts University, Medford, Massachusetts, 02155, United States of America
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3
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Ito F, Li Z, Minakhin L, Chandramouly G, Tyagi M, Betsch R, Krais JJ, Taberi B, Vekariya U, Calbert M, Skorski T, Johnson N, Chen XS, Pomerantz RT. Structural basis for a Polθ helicase small-molecule inhibitor revealed by cryo-EM. Nat Commun 2024; 15:7003. [PMID: 39143110 PMCID: PMC11324745 DOI: 10.1038/s41467-024-51351-4] [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: 08/11/2023] [Accepted: 08/05/2024] [Indexed: 08/16/2024] Open
Abstract
DNA polymerase theta (Polθ) is a DNA helicase-polymerase protein that facilitates DNA repair and is synthetic lethal with homology-directed repair (HDR) factors. Thus, Polθ is a promising precision oncology drug-target in HDR-deficient cancers. Here, we characterize the binding and mechanism of action of a Polθ helicase (Polθ-hel) small-molecule inhibitor (AB25583) using cryo-EM. AB25583 exhibits 6 nM IC50 against Polθ-hel, selectively kills BRCA1/2-deficient cells, and acts synergistically with olaparib in cancer cells harboring pathogenic BRCA1/2 mutations. Cryo-EM uncovers predominantly dimeric Polθ-hel:AB25583 complex structures at 3.0-3.2 Å. The structures reveal a binding-pocket deep inside the helicase central-channel, which underscores the high specificity and potency of AB25583. The cryo-EM structures in conjunction with biochemical data indicate that AB25583 inhibits the ATPase activity of Polθ-hel helicase via an allosteric mechanism. These detailed structural data and insights about AB25583 inhibition pave the way for accelerating drug development targeting Polθ-hel in HDR-deficient cancers.
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Affiliation(s)
- Fumiaki Ito
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, California, CA, 90089, USA
| | - Ziyuan Li
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, California, CA, 90089, USA
| | - Leonid Minakhin
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Gurushankar Chandramouly
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Mrityunjay Tyagi
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Robert Betsch
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - John J Krais
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Bernadette Taberi
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Umeshkumar Vekariya
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Marissa Calbert
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Tomasz Skorski
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Neil Johnson
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Xiaojiang S Chen
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, California, CA, 90089, USA.
| | - Richard T Pomerantz
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA.
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4
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Toraason E, Salagean A, Almanzar DE, Brown JE, Richter CM, Kurhanewicz NA, Rog O, Libuda DE. BRCA1/BRC-1 and SMC-5/6 regulate DNA repair pathway engagement during Caenorhabditis elegans meiosis. eLife 2024; 13:e80687. [PMID: 39115289 PMCID: PMC11368404 DOI: 10.7554/elife.80687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 08/07/2024] [Indexed: 09/03/2024] Open
Abstract
The preservation of genome integrity during sperm and egg development is vital for reproductive success. During meiosis, the tumor suppressor BRCA1/BRC-1 and structural maintenance of chromosomes 5/6 (SMC-5/6) complex genetically interact to promote high fidelity DNA double strand break (DSB) repair, but the specific DSB repair outcomes these proteins regulate remain unknown. Using genetic and cytological methods to monitor resolution of DSBs with different repair partners in Caenorhabditis elegans, we demonstrate that both BRC-1 and SMC-5 repress intersister crossover recombination events. Sequencing analysis of conversion tracts from homolog-independent DSB repair events further indicates that BRC-1 regulates intersister/intrachromatid noncrossover conversion tract length. Moreover, we find that BRC-1 specifically inhibits error prone repair of DSBs induced at mid-pachytene. Finally, we reveal functional interactions of BRC-1 and SMC-5/6 in regulating repair pathway engagement: BRC-1 is required for localization of recombinase proteins to DSBs in smc-5 mutants and enhances DSB repair defects in smc-5 mutants by repressing theta-mediated end joining (TMEJ). These results are consistent with a model in which some functions of BRC-1 act upstream of SMC-5/6 to promote recombination and inhibit error-prone DSB repair, while SMC-5/6 acts downstream of BRC-1 to regulate the formation or resolution of recombination intermediates. Taken together, our study illuminates the coordinated interplay of BRC-1 and SMC-5/6 to regulate DSB repair outcomes in the germline.
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Affiliation(s)
- Erik Toraason
- Institute of Molecular Biology, Department of Biology, University of OregonEugeneUnited States
| | - Alina Salagean
- Institute of Molecular Biology, Department of Biology, University of OregonEugeneUnited States
| | - David E Almanzar
- School of Biological Sciences and Center for Cell and Genome Sciences, University of UtahSalt Lake CityUnited States
| | - Jordan E Brown
- Institute of Molecular Biology, Department of Biology, University of OregonEugeneUnited States
| | - Colette M Richter
- Institute of Molecular Biology, Department of Biology, University of OregonEugeneUnited States
| | - Nicole A Kurhanewicz
- Institute of Molecular Biology, Department of Biology, University of OregonEugeneUnited States
| | - Ofer Rog
- School of Biological Sciences and Center for Cell and Genome Sciences, University of UtahSalt Lake CityUnited States
| | - Diana E Libuda
- Institute of Molecular Biology, Department of Biology, University of OregonEugeneUnited States
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5
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Vekariya U, Minakhin L, Chandramouly G, Tyagi M, Kent T, Sullivan-Reed K, Atkins J, Ralph D, Nieborowska-Skorska M, Kukuyan AM, Tang HY, Pomerantz RT, Skorski T. PARG is essential for Polθ-mediated DNA end-joining by removing repressive poly-ADP-ribose marks. Nat Commun 2024; 15:5822. [PMID: 38987289 PMCID: PMC11236980 DOI: 10.1038/s41467-024-50158-7] [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: 08/29/2023] [Accepted: 06/27/2024] [Indexed: 07/12/2024] Open
Abstract
DNA polymerase theta (Polθ)-mediated end-joining (TMEJ) repairs DNA double-strand breaks and confers resistance to genotoxic agents. How Polθ is regulated at the molecular level to exert TMEJ remains poorly characterized. We find that Polθ interacts with and is PARylated by PARP1 in a HPF1-independent manner. PARP1 recruits Polθ to the vicinity of DNA damage via PARylation dependent liquid demixing, however, PARylated Polθ cannot perform TMEJ due to its inability to bind DNA. PARG-mediated de-PARylation of Polθ reactivates its DNA binding and end-joining activities. Consistent with this, PARG is essential for TMEJ and the temporal recruitment of PARG to DNA damage corresponds with TMEJ activation and dissipation of PARP1 and PAR. In conclusion, we show a two-step spatiotemporal mechanism of TMEJ regulation. First, PARP1 PARylates Polθ and facilitates its recruitment to DNA damage sites in an inactivated state. PARG subsequently activates TMEJ by removing repressive PAR marks on Polθ.
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Affiliation(s)
- Umeshkumar Vekariya
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Leonid Minakhin
- Thomas Jefferson University, Sidney Kimmel Cancer Center, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Gurushankar Chandramouly
- Thomas Jefferson University, Sidney Kimmel Cancer Center, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Mrityunjay Tyagi
- Thomas Jefferson University, Sidney Kimmel Cancer Center, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Tatiana Kent
- Thomas Jefferson University, Sidney Kimmel Cancer Center, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Katherine Sullivan-Reed
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Jessica Atkins
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Douglas Ralph
- Thomas Jefferson University, Sidney Kimmel Cancer Center, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Margaret Nieborowska-Skorska
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Anna-Mariya Kukuyan
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Hsin-Yao Tang
- Proteomics and Metabolomics Facility, The Wistar Institute, Philadelphia, PA, 19104, USA
| | - Richard T Pomerantz
- Thomas Jefferson University, Sidney Kimmel Cancer Center, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA.
| | - Tomasz Skorski
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA.
- Department of Cancer and Cellular Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA.
- Nuclear Dynamics and Cancer Program, Fox Chase Cancer Center, Philadelphia, PA, USA.
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6
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Carvajal-Maldonado D, Li Y, Returan M, Averill AM, Doublié S, Wood RD. Dynamic stem-loop extension by Pol θ and templated insertion during DNA repair. J Biol Chem 2024; 300:107461. [PMID: 38876299 PMCID: PMC11292364 DOI: 10.1016/j.jbc.2024.107461] [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: 04/17/2024] [Revised: 05/26/2024] [Accepted: 05/28/2024] [Indexed: 06/16/2024] Open
Abstract
Theta-mediated end joining (TMEJ) is critical for survival of cancer cells when other DNA double-stranded break repair pathways are impaired. Human DNA polymerase theta (Pol θ) can extend ssDNA oligonucleotides, but little is known about preferred substrates and mechanism. We show that Pol θ can extend both ssDNA and RNA substrates by unimolecular stem-loop synthesis initiated by only two 3' terminal base pairs. Given sufficient time, Pol θ uses alternative pairing configurations that greatly expand the repertoire of sequence outcomes. Further primer-template adjustments yield low-fidelity outcomes when the nucleotide pool is imbalanced. Unimolecular stem-loop synthesis competes with bimolecular end joining, even when a longer terminal microhomology for end joining is available. Both reactions are partially suppressed by the ssDNA-binding protein replication protein A. Protein-primer grasp residues that are specific to Pol θ are needed for rapid stem-loop synthesis. The ability to perform stem-loop synthesis from a minimally paired primer is rare among human DNA polymerases, but we show that human DNA polymerases Pol η and Pol λ can catalyze related reactions. Using purified human Pol θ, we reconstituted in vitro TMEJ incorporating an insertion arising from a stem-loop extension. These activities may help explain TMEJ repair events that include inverted repeat sequences.
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Affiliation(s)
- Denisse Carvajal-Maldonado
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, Texas, USA
| | - Yuzhen Li
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, Texas, USA
| | - Mark Returan
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, Texas, USA
| | - April M Averill
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, USA
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, USA
| | - Richard D Wood
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, Texas, USA.
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7
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Ito F, Li Z, Minakhin L, Khant HA, Pomerantz RT, Chen XS. Structural Basis for Polθ-Helicase DNA Binding and Microhomology-Mediated End-Joining. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.07.597860. [PMID: 38895274 PMCID: PMC11185775 DOI: 10.1101/2024.06.07.597860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
DNA double-strand breaks (DSBs) present a critical threat to genomic integrity, often precipitating genomic instability and oncogenesis. Repair of DSBs predominantly occurs through homologous recombination (HR) and non-homologous end joining (NHEJ). In HR-deficient cells, DNA polymerase theta (Polθ) becomes critical for DSB repair via microhomology-mediated end joining (MMEJ), also termed theta-mediated end joining (TMEJ). Thus, Polθ is synthetically lethal with BRCA1/2 and other HR factors, underscoring its potential as a therapeutic target in HR-deficient cancers. However, the molecular mechanisms governing Polθ-mediated MMEJ remain poorly understood. Here we present a series of cryo-electron microscopy structures of the Polθ helicase domain (Polθ-hel) in complex with DNA containing 3'-overhang. The structures reveal the sequential conformations adopted by Polθ-hel during the critical phases of DNA binding, microhomology searching, and microhomology annealing. The stepwise conformational changes within the Polθ-hel subdomains and its functional dimeric state are pivotal for aligning the 3'-overhangs, facilitating the microhomology search and subsequent annealing necessary for DSB repair via MMEJ. Our findings illustrate the essential molecular switches within Polθ-hel that orchestrate the MMEJ process in DSB repair, laying the groundwork for the development of targeted therapies against the Polθ-hel.
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Affiliation(s)
- Fumiaki Ito
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, California, 90089, USA
- Department of Microbiology, Immunology and Molecular Genetics
- California NanoSystems Institute, University of California, Los Angeles, CA90095, USA
| | - Ziyuan Li
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, California, 90089, USA
| | - Leonid Minakhin
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Htet A. Khant
- USC Center of Excellence for Nano-Imaging, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - Richard T. Pomerantz
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Xiaojiang S. Chen
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, California, 90089, USA
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8
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Zerio CJ, Bai Y, Sosa-Alvarado BA, Guzi T, Lander GC. Human polymerase theta helicase positions DNA microhomologies for double-strand break repair. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.26.591388. [PMID: 38712090 PMCID: PMC11071473 DOI: 10.1101/2024.04.26.591388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
DNA double-strand breaks occur in all human cells on a daily basis and must be repaired with high fidelity to minimize genomic instability1. Deficiencies in high-fidelity DNA repair by homologous recombination lead to dependence on DNA polymerase theta, which identifies DNA microhomologies in 3' single-stranded DNA overhangs and anneals them to initiate error-prone double-strand break repair. The resulting genomic instability is associated with numerous cancers, thereby making this polymerase an attractive therapeutic target2,3. However, despite the biomedical importance of polymerase theta, the molecular details of how it initiates DNA break repair remain unclear4,5. Here we present cryo-electron microscopy structures of the polymerase theta helicase domain bound to microhomology-containing DNA, revealing DNA-induced rearrangements of the helicase that enable DNA repair. Our structures show that DNA-bound helicase dimers facilitate a microhomology search that positions 3' single-stranded DNA ends in proximity to align complementary base pairs and anneal DNA microhomology. We define the molecular determinants that enable the polymerase theta helicase domain to identify and pair DNA microhomologies to initiate mutagenic DNA repair, providing mechanistic insights into therapeutic targeting of these interactions.
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Affiliation(s)
- Christopher J. Zerio
- Department of Integrative Structural and Computational Biology, Scripps Research; La Jolla, CA, USA
| | | | | | | | - Gabriel C. Lander
- Department of Integrative Structural and Computational Biology, Scripps Research; La Jolla, CA, USA
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9
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Fijen C, Drogalis Beckham L, Terino D, Li Y, Ramsden DA, Wood RD, Doublié S, Rothenberg E. Sequential requirements for distinct Polθ domains during theta-mediated end joining. Mol Cell 2024; 84:1460-1474.e6. [PMID: 38640894 PMCID: PMC11031631 DOI: 10.1016/j.molcel.2024.03.010] [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: 03/29/2023] [Revised: 01/10/2024] [Accepted: 03/12/2024] [Indexed: 04/21/2024]
Abstract
DNA polymerase θ (Polθ) plays a central role in a DNA double-strand break repair pathway termed theta-mediated end joining (TMEJ). TMEJ functions by pairing short-sequence "microhomologies" (MHs) in single-stranded DNA at each end of a break and subsequently initiating DNA synthesis. It is not known how the Polθ helicase domain (HD) and polymerase domain (PD) operate to bring together MHs and facilitate repair. To resolve these transient processes in real time, we utilized in vitro single-molecule FRET approaches and biochemical analyses. We find that the Polθ-HD mediates the initial capture of two ssDNA strands, bringing them in close proximity. The Polθ-PD binds and stabilizes pre-annealed MHs to form a synaptic complex (SC) and initiate repair synthesis. Individual synthesis reactions show that Polθ is inherently non-processive, accounting for complex mutational patterns during TMEJ. Binding of Polθ-PD to stem-loop-forming sequences can substantially limit synapsis, depending on the available dNTPs and sequence context.
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Affiliation(s)
- Carel Fijen
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY 10016, USA.
| | - Lea Drogalis Beckham
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
| | - Dante Terino
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Yuzhen Li
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA
| | - Dale A Ramsden
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Richard D Wood
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY 10016, USA.
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10
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Ronson GE, Starowicz K, Anthony EJ, Piberger AL, Clarke LC, Garvin AJ, Beggs AD, Whalley CM, Edmonds MJ, Beesley JFJ, Morris JR. Mechanisms of synthetic lethality between BRCA1/2 and 53BP1 deficiencies and DNA polymerase theta targeting. Nat Commun 2023; 14:7834. [PMID: 38030626 PMCID: PMC10687250 DOI: 10.1038/s41467-023-43677-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 11/16/2023] [Indexed: 12/01/2023] Open
Abstract
A synthetic lethal relationship exists between disruption of polymerase theta (Polθ), and loss of either 53BP1 or homologous recombination (HR) proteins, including BRCA1; however, the mechanistic basis of these observations are unclear. Here we reveal two distinct mechanisms of Polθ synthetic lethality, identifying dual influences of 1) whether Polθ is lost or inhibited, and 2) the underlying susceptible genotype. Firstly, we find that the sensitivity of BRCA1/2- and 53BP1-deficient cells to Polθ loss, and 53BP1-deficient cells to Polθ inhibition (ART558) requires RAD52, and appropriate reduction of RAD52 can ameliorate these phenotypes. We show that in the absence of Polθ, RAD52 accumulations suppress ssDNA gap-filling in G2/M and encourage MRE11 nuclease accumulation. In contrast, the survival of BRCA1-deficient cells treated with Polθ inhibitor are not restored by RAD52 suppression, and ssDNA gap-filling is prevented by the chemically inhibited polymerase itself. These data define an additional role for Polθ, reveal the mechanism underlying synthetic lethality between 53BP1, BRCA1/2 and Polθ loss, and indicate genotype-dependent Polθ inhibitor mechanisms.
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Affiliation(s)
- George E Ronson
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Katarzyna Starowicz
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
- Adthera Bio, Lyndon House, 62 Hagley Road, Birmingham, B16 8PE, UK
| | - Elizabeth J Anthony
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Ann Liza Piberger
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Lucy C Clarke
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
- West Midlands Regional Genetics Laboratory, Birmingham Women's Hospital, Mindelsohn Way, Birmingham, B15 2TG, UK
| | - Alexander J Garvin
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
- University of Leeds, Leeds, UK
| | - Andrew D Beggs
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
- Genomics Birmingham, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Celina M Whalley
- Genomics Birmingham, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Matthew J Edmonds
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
- Certara Insight, Danebrook Court, Oxford Office Village, Kidlington, Oxfordshire, OX5 1LQ, UK
| | - James F J Beesley
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Joanna R Morris
- Birmingham Centre for Genome Biology and Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
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11
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Krais JJ, Glass DJ, Chudoba I, Wang Y, Feng W, Simpson D, Patel P, Liu Z, Neumann-Domer R, Betsch RG, Bernhardy AJ, Bradbury AM, Conger J, Yueh WT, Nacson J, Pomerantz RT, Gupta GP, Testa JR, Johnson N. Genetic separation of Brca1 functions reveal mutation-dependent Polθ vulnerabilities. Nat Commun 2023; 14:7714. [PMID: 38001070 PMCID: PMC10673838 DOI: 10.1038/s41467-023-43446-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023] Open
Abstract
Homologous recombination (HR)-deficiency induces a dependency on DNA polymerase theta (Polθ/Polq)-mediated end joining, and Polθ inhibitors (Polθi) are in development for cancer therapy. BRCA1 and BRCA2 deficient cells are thought to be synthetic lethal with Polθ, but whether distinct HR gene mutations give rise to equivalent Polθ-dependence, and the events that drive lethality, are unclear. In this study, we utilized mouse models with separate Brca1 functional defects to mechanistically define Brca1-Polθ synthetic lethality. Surprisingly, homozygous Brca1 mutant, Polq-/- cells were viable, but grew slowly and had chromosomal instability. Brca1 mutant cells proficient in DNA end resection were significantly more dependent on Polθ for viability; here, treatment with Polθi elevated RPA foci, which persisted through mitosis. In an isogenic system, BRCA1 null cells were defective, but PALB2 and BRCA2 mutant cells exhibited active resection, and consequently stronger sensitivity to Polθi. Thus, DNA end resection is a critical determinant of Polθi sensitivity in HR-deficient cells, and should be considered when selecting patients for clinical studies.
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Affiliation(s)
- John J Krais
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA.
- Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA.
| | - David J Glass
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
- Temple University, Lewis Katz School of Medicine, Philadelphia, PA, 19140, USA
| | - Ilse Chudoba
- MetaSystems Probes, GmbH, Industriestr, 68804, Altlussheim, Germany
| | - Yifan Wang
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Wanjuan Feng
- Department of Radiation Oncology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Dennis Simpson
- Department of Radiation Oncology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Pooja Patel
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Zemin Liu
- Cytogenetics Laboratory, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Ryan Neumann-Domer
- Cytogenetics Laboratory, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Robert G Betsch
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Andrea J Bernhardy
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Alice M Bradbury
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Jason Conger
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Wei-Ting Yueh
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Joseph Nacson
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Richard T Pomerantz
- Thomas Jefferson University, Sidney Kimmel Cancer Center, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Gaorav P Gupta
- Cancer Control and Prevention Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Joseph R Testa
- Cytogenetics Laboratory, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
- Cancer Control and Prevention Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Neil Johnson
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA.
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12
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Syed A, Filandr F, Patterson-Fortin J, Bacolla A, Ravindranathan R, Zhou J, McDonald D, Albuhluli M, Verway-Cohen A, Newman J, Tsai MS, Jones D, Schriemer D, D’Andrea A, Tainer J. Novobiocin blocks nucleic acid binding to Polθ and inhibits stimulation of its ATPase activity. Nucleic Acids Res 2023; 51:9920-9937. [PMID: 37665033 PMCID: PMC10570058 DOI: 10.1093/nar/gkad727] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 08/10/2023] [Accepted: 08/24/2023] [Indexed: 09/05/2023] Open
Abstract
Polymerase theta (Polθ) acts in DNA replication and repair, and its inhibition is synthetic lethal in BRCA1 and BRCA2-deficient tumor cells. Novobiocin (NVB) is a first-in-class inhibitor of the Polθ ATPase activity, and it is currently being tested in clinical trials as an anti-cancer drug. Here, we investigated the molecular mechanism of NVB-mediated Polθ inhibition. Using hydrogen deuterium exchange-mass spectrometry (HX-MS), biophysical, biochemical, computational and cellular assays, we found NVB is a non-competitive inhibitor of ATP hydrolysis. NVB sugar group deletion resulted in decreased potency and reduced HX-MS interactions, supporting a specific NVB binding orientation. Collective results revealed that NVB binds to an allosteric site to block DNA binding, both in vitro and in cells. Comparisons of The Cancer Genome Atlas (TCGA) tumors and matched controls implied that POLQ upregulation in tumors stems from its role in replication stress responses to increased cell proliferation: this can now be tested in fifteen tumor types by NVB blocking ssDNA-stimulation of ATPase activity, required for Polθ function at replication forks and DNA damage sites. Structural and functional insights provided in this study suggest a path for developing NVB derivatives with improved potency for Polθ inhibition by targeting ssDNA binding with entropically constrained small molecules.
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Affiliation(s)
- Aleem Syed
- Division of Radiation and Genome Instability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Frantisek Filandr
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Jeffrey Patterson-Fortin
- Division of Radiation and Genome Instability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Albino Bacolla
- Department of Molecular and Cellular Oncology, Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ramya Ravindranathan
- Division of Radiation and Genome Instability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Jia Zhou
- Division of Radiation and Genome Instability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Drew T McDonald
- Biological and System Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Mohammed E Albuhluli
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Amy Verway-Cohen
- Biological and System Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Joseph A Newman
- Center for Medicines Discovery, University of Oxford, OX1 3QU, UK
| | - Miaw-Sheue Tsai
- Biological and System Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Darin E Jones
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - David C Schriemer
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Alan D D’Andrea
- Division of Radiation and Genome Instability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
- Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - John A Tainer
- Department of Molecular and Cellular Oncology, Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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13
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Irvin EM, Wang H. Single-molecule imaging of genome maintenance proteins encountering specific DNA sequences and structures. DNA Repair (Amst) 2023; 128:103528. [PMID: 37392578 PMCID: PMC10989508 DOI: 10.1016/j.dnarep.2023.103528] [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: 04/08/2023] [Revised: 06/08/2023] [Accepted: 06/21/2023] [Indexed: 07/03/2023]
Abstract
DNA repair pathways are tightly regulated processes that recognize specific hallmarks of DNA damage and coordinate lesion repair through discrete mechanisms, all within the context of a three-dimensional chromatin landscape. Dysregulation or malfunction of any one of the protein constituents in these pathways can contribute to aging and a variety of diseases. While the collective action of these many proteins is what drives DNA repair on the organismal scale, it is the interactions between individual proteins and DNA that facilitate each step of these pathways. In much the same way that ensemble biochemical techniques have characterized the various steps of DNA repair pathways, single-molecule imaging (SMI) approaches zoom in further, characterizing the individual protein-DNA interactions that compose each pathway step. SMI techniques offer the high resolving power needed to characterize the molecular structure and functional dynamics of individual biological interactions on the nanoscale. In this review, we highlight how our lab has used SMI techniques - traditional atomic force microscopy (AFM) imaging in air, high-speed AFM (HS-AFM) in liquids, and the DNA tightrope assay - over the past decade to study protein-nucleic acid interactions involved in DNA repair, mitochondrial DNA replication, and telomere maintenance. We discuss how DNA substrates containing specific DNA sequences or structures that emulate DNA repair intermediates or telomeres were generated and validated. For each highlighted project, we discuss novel findings made possible by the spatial and temporal resolution offered by these SMI techniques and unique DNA substrates.
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Affiliation(s)
| | - Hong Wang
- Toxicology Program, North Carolina State University, Raleigh, NC, USA; Physics Department, North Carolina State University, Raleigh, NC, USA; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA.
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14
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Pismataro MC, Astolfi A, Barreca ML, Pacetti M, Schenone S, Bandiera T, Carbone A, Massari S. Small Molecules Targeting DNA Polymerase Theta (POLθ) as Promising Synthetic Lethal Agents for Precision Cancer Therapy. J Med Chem 2023; 66:6498-6522. [PMID: 37134182 DOI: 10.1021/acs.jmedchem.2c02101] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Synthetic lethality (SL) is an innovative strategy in targeted anticancer therapy that exploits tumor genetic vulnerabilities. This topic has come to the forefront in recent years, as witnessed by the increased number of publications since 2007. The first proof of concept for the effectiveness of SL was provided by the approval of poly(ADP-ribose)polymerase inhibitors, which exploit a SL interaction in BRCA-deficient cells, although their use is limited by resistance. Searching for additional SL interactions involving BRCA mutations, the DNA polymerase theta (POLθ) emerged as an exciting target. This review summarizes, for the first time, the POLθ polymerase and helicase inhibitors reported to date. Compounds are described focusing on chemical structure and biological activity. With the aim to enable further drug discovery efforts in interrogating POLθ as a target, we propose a plausible pharmacophore model for POLθ-pol inhibitors and provide a structural analysis of the known POLθ ligand binding sites.
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Affiliation(s)
- Maria Chiara Pismataro
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Andrea Astolfi
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Maria Letizia Barreca
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Martina Pacetti
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Silvia Schenone
- Department of Pharmacy, University of Genoa, Viale Benedetto XV 3, 16132 Genoa, Italy
| | - Tiziano Bandiera
- D3 PharmaChemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Anna Carbone
- Department of Pharmacy, University of Genoa, Viale Benedetto XV 3, 16132 Genoa, Italy
| | - Serena Massari
- Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06123 Perugia, Italy
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15
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Yi G, Sung Y, Kim C, Ra JS, Hirakawa H, Kato T, Fujimori A, Kim H, Takata KI. DNA polymerase θ-mediated repair of high LET radiation-induced complex DNA double-strand breaks. Nucleic Acids Res 2023; 51:2257-2269. [PMID: 36805268 PMCID: PMC10018357 DOI: 10.1093/nar/gkad076] [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: 07/19/2022] [Revised: 01/21/2023] [Accepted: 01/25/2023] [Indexed: 02/22/2023] Open
Abstract
DNA polymerase θ (POLQ) is a unique DNA polymerase that is able to perform microhomology-mediated end-joining as well as translesion synthesis (TLS) across an abasic (AP) site and thymine glycol (Tg). However, the biological significance of the TLS activity is currently unknown. Herein we provide evidence that the TLS activity of POLQ plays a critical role in repairing complex DNA double-strand breaks (DSBs) induced by high linear energy transfer (LET) radiation. Radiotherapy with high LET radiation such as carbon ions leads to more deleterious biological effects than corresponding doses of low LET radiation such as X-rays. High LET-induced DSBs are considered to be complex, carrying additional DNA damage such as AP site and Tg in close proximity to the DSB sites. However, it is not clearly understood how complex DSBs are processed in mammalian cells. We demonstrated that genetic disruption of POLQ results in an increase of chromatid breaks and enhanced cellular sensitivity following treatment with high LET radiation. At the biochemical level, POLQ was able to bypass an AP site and Tg during end-joining and was able to anneal two single-stranded DNA tails when DNA lesions were located outside the microhomology. This study offers evidence that POLQ is directly involved in the repair of complex DSBs.
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Affiliation(s)
- Geunil Yi
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Yubin Sung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Chanwoo Kim
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Jae Sun Ra
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Hirokazu Hirakawa
- Department of Charged Particle Therapy Research, Institute for Quantum Medical Science, Chiba 263-8555, Japan
| | - Takamitsu A Kato
- Department of Environmental & Radiological Health Sciences, Colorado State University, Colorado 80523, USA
| | - Akira Fujimori
- Department of Charged Particle Therapy Research, Institute for Quantum Medical Science, Chiba 263-8555, Japan
| | - Hajin Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Kei-ichi Takata
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
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16
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Multifaceted Nature of DNA Polymerase θ. Int J Mol Sci 2023; 24:ijms24043619. [PMID: 36835031 PMCID: PMC9962433 DOI: 10.3390/ijms24043619] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/26/2023] [Accepted: 02/02/2023] [Indexed: 02/15/2023] Open
Abstract
DNA polymerase θ belongs to the A family of DNA polymerases and plays a key role in DNA repair and damage tolerance, including double-strand break repair and DNA translesion synthesis. Pol θ is often overexpressed in cancer cells and promotes their resistance to chemotherapeutic agents. In this review, we discuss unique biochemical properties and structural features of Pol θ, its multiple roles in protection of genome stability and the potential of Pol θ as a target for cancer treatment.
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17
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Li C, Zhu H, Jin S, Maksoud LM, Jain N, Sun J, Gao Y. Structural basis of DNA polymerase θ mediated DNA end joining. Nucleic Acids Res 2023; 51:463-474. [PMID: 36583344 PMCID: PMC9841435 DOI: 10.1093/nar/gkac1201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/30/2022] [Accepted: 12/05/2022] [Indexed: 12/31/2022] Open
Abstract
DNA polymerase θ (Pol θ) plays an essential role in the microhomology-mediated end joining (MMEJ) pathway for repairing DNA double-strand breaks. However, the mechanisms by which Pol θ recognizes microhomologous DNA ends and performs low-fidelity DNA synthesis remain unclear. Here, we present cryo-electron microscope structures of the polymerase domain of Lates calcarifer Pol θ with long and short duplex DNA at up to 2.4 Å resolution. Interestingly, Pol θ binds to long and short DNA substrates similarly, with extensive interactions around the active site. Moreover, Pol θ shares a similar active site as high-fidelity A-family polymerases with its finger domain well-closed but differs in having hydrophilic residues surrounding the nascent base pair. Computational simulations and mutagenesis studies suggest that the unique insertion loops of Pol θ help to stabilize short DNA binding and assemble the active site for MMEJ repair. Taken together, our results illustrate the structural basis of Pol θ-mediated MMEJ.
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Affiliation(s)
- Chuxuan Li
- Department of Biosciences, Rice University, Houston, TX 77005, USA
| | - Hanwen Zhu
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Shikai Jin
- Department of Biosciences, Rice University, Houston, TX 77005, USA
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA
| | - Leora M Maksoud
- Department of Biosciences, Rice University, Houston, TX 77005, USA
| | - Nikhil Jain
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Ji Sun
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Yang Gao
- Department of Biosciences, Rice University, Houston, TX 77005, USA
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18
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Tamura T, Yamamoto Shimojima K, Okamoto N, Yagasaki H, Morioka I, Kanno H, Minakuchi Y, Toyoda A, Yamamoto T. Long-read sequence analysis for clustered genomic copy number aberrations revealed architectures of intricately intertwined rearrangements. Am J Med Genet A 2023; 191:112-119. [PMID: 36282026 DOI: 10.1002/ajmg.a.62997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 07/13/2022] [Accepted: 08/24/2022] [Indexed: 12/14/2022]
Abstract
Most chromosomal aberrations revealed by chromosomal microarray testing (CMA) are simple; however, very complex chromosomal structural rearrangements can also be found. Although the mechanism of structural rearrangements has been gradually revealed, not all mechanisms have been elucidated. We analyzed the breakpoint-junctions (BJs) of two or more clustered copy number variations (CNVs) in the same chromosome arms to understand their conformation and the mechanism of complex structural rearrangements. Combining CMA with long-read whole-genome sequencing (WGS) analysis, we successfully determined all BJs for the clustered CNVs identified in four patients. Multiple CNVs were intricately intertwined with each other, and clustered CNVs in four patients were involved in global complex chromosomal rearrangements. The BJs of two clustered deletions identified in two patients showed microhomologies, and their characteristics were explained by chromothripsis. In contrast, the BJs in the other two patients, who showed clustered deletions and duplications, consisted of blunt-end and nontemplated insertions. These findings could be explained only by alternative nonhomologous end-joining, a mechanism related to polymerase theta. All the patients had at least one inverted segment. Three patients showed cryptic aberrations involving a disruption and a deletion/duplication, which were not detected by CMA but were first identified by WGS. This result suggested that complex rearrangements should be considered if clustered CNVs are observed in the same chromosome arms. Because CMA has potential limitations in genotype-phenotype correlation analysis, a more detailed analysis by whole genome examination is recommended in cases of suspected complex structural aberrations.
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Affiliation(s)
- Takeaki Tamura
- Department of Pediatrics and Child Health, Nihon University School of Medicine, Tokyo, Japan.,Division of Gene Medicine, Graduate School of Medical Science, Tokyo Women's Medical University, Tokyo, Japan.,Department of Transfusion Medicine and Cell Processing, Tokyo Women's Medical University, Tokyo, Japan
| | - Keiko Yamamoto Shimojima
- Department of Transfusion Medicine and Cell Processing, Tokyo Women's Medical University, Tokyo, Japan.,Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Nobuhiko Okamoto
- Department of Medical Genetics, Osaka Women's and Children's Hospital, Izumi, Japan
| | - Hiroshi Yagasaki
- Department of Pediatrics and Child Health, Nihon University School of Medicine, Tokyo, Japan
| | - Ichiro Morioka
- Department of Pediatrics and Child Health, Nihon University School of Medicine, Tokyo, Japan
| | - Hitoshi Kanno
- Department of Transfusion Medicine and Cell Processing, Tokyo Women's Medical University, Tokyo, Japan.,Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Yohei Minakuchi
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Atsushi Toyoda
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Toshiyuki Yamamoto
- Division of Gene Medicine, Graduate School of Medical Science, Tokyo Women's Medical University, Tokyo, Japan.,Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
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19
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Zhu T, Zheng JY, Huang LL, Wang YH, Yao DF, Dai HB. Human PARP1 substrates and regulators of its catalytic activity: An updated overview. Front Pharmacol 2023; 14:1137151. [PMID: 36909172 PMCID: PMC9995695 DOI: 10.3389/fphar.2023.1137151] [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: 01/04/2023] [Accepted: 02/09/2023] [Indexed: 02/25/2023] Open
Abstract
Poly (ADP-ribose) polymerase 1 (PARP1) is a key DNA damage sensor that is recruited to damaged sites after DNA strand breaks to initiate DNA repair. This is achieved by catalyzing attachment of ADP-ribose moieties, which are donated from NAD+, on the amino acid residues of itself or other acceptor proteins. PARP inhibitors (PARPi) that inhibit PARP catalytic activity and induce PARP trapping are commonly used for treating BRCA1/2-deficient breast and ovarian cancers through synergistic lethality. Unfortunately, resistance to PARPi frequently occurs. In this review, we present the novel substrates and regulators of the PARP1-catalyzed poly (ADP-ribosyl)ation (PARylatison) that have been identified in the last 3 years. The overall aim is the presentation of protein interactions of potential therapeutic intervention for overcoming the resistance to PARPi.
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Affiliation(s)
- Tao Zhu
- Department of Pharmacy, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ju-Yan Zheng
- Institute of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, China
| | - Ling-Ling Huang
- Department of Pharmacy, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yan-Hong Wang
- Department of Pharmacy, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Di-Fei Yao
- Department of Pharmacy, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Hai-Bin Dai
- Department of Pharmacy, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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20
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Barszczewska-Pietraszek G, Drzewiecka M, Czarny P, Skorski T, Śliwiński T. Polθ Inhibition: An Anticancer Therapy for HR-Deficient Tumours. Int J Mol Sci 2022; 24:ijms24010319. [PMID: 36613762 PMCID: PMC9820168 DOI: 10.3390/ijms24010319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/15/2022] [Accepted: 12/17/2022] [Indexed: 12/28/2022] Open
Abstract
DNA polymerase theta (Polθ)-mediated end joining (TMEJ) is, along with homologous recombination (HR) and non-homologous end-joining (NHEJ), one of the most important mechanisms repairing potentially lethal DNA double-strand breaks (DSBs). Polθ is becoming a new target in cancer research because it demonstrates numerous synthetically lethal interactions with other DNA repair mechanisms, e.g., those involving PARP1, BRCA1/2, DNA-PK, ATR. Inhibition of Polθ could be achieved with different methods, such as RNA interference (RNAi), CRISPR/Cas9 technology, or using small molecule inhibitors. In the context of this topic, RNAi and CRISPR/Cas9 are still more often applied in the research itself rather than clinical usage, different than small molecule inhibitors. Several Polθ inhibitors have been already generated, and two of them, novobiocin (NVB) and ART812 derivative, are being tested in clinical trials against HR-deficient tumors. In this review, we describe the significance of Polθ and the Polθ-mediated TMEJ pathway. In addition, we summarize the current state of knowledge about Polθ inhibitors and emphasize the promising role of Polθ as a therapeutic target.
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Affiliation(s)
| | - Małgorzata Drzewiecka
- Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland
| | - Piotr Czarny
- Department of Medical Biochemistry, Medical University of Lodz, 92-216 Lodz, Poland
| | - Tomasz Skorski
- Fels Cancer Institute for Personalized Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Tomasz Śliwiński
- Laboratory of Medical Genetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland
- Correspondence: ; Tel.: +48-42-635-44-86
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21
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Belan O, Sebald M, Adamowicz M, Anand R, Vancevska A, Neves J, Grinkevich V, Hewitt G, Segura-Bayona S, Bellelli R, Robinson HMR, Higgins GS, Smith GCM, West SC, Rueda DS, Boulton SJ. POLQ seals post-replicative ssDNA gaps to maintain genome stability in BRCA-deficient cancer cells. Mol Cell 2022; 82:4664-4680.e9. [PMID: 36455556 DOI: 10.1016/j.molcel.2022.11.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 10/19/2022] [Accepted: 11/08/2022] [Indexed: 12/03/2022]
Abstract
POLQ is a key effector of DSB repair by microhomology-mediated end-joining (MMEJ) and is overexpressed in many cancers. POLQ inhibitors confer synthetic lethality in HR and Shieldin-deficient cancer cells, which has been proposed to reflect a critical dependence on the DSB repair pathway by MMEJ. Whether POLQ also operates independent of MMEJ remains unexplored. Here, we show that POLQ-deficient cells accumulate post-replicative ssDNA gaps upon BRCA1/2 loss or PARP inhibitor treatment. Biochemically, cooperation between POLQ helicase and polymerase activities promotes RPA displacement and ssDNA-gap fill-in, respectively. POLQ is also capable of microhomology-mediated gap skipping (MMGS), which generates deletions during gap repair that resemble the genomic scars prevalent in POLQ overexpressing cancers. Our findings implicate POLQ in mutagenic post-replicative gap sealing, which could drive genome evolution in cancer and whose loss places a critical dependency on HR for gap protection and repair and cellular viability.
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Affiliation(s)
- Ondrej Belan
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Marie Sebald
- DNA Recombination and Repair Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Marek Adamowicz
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Roopesh Anand
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Aleksandra Vancevska
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Joana Neves
- Artios Pharma Ltd., B940 Babraham Research Campus, Cambridge CB22 3FH, UK
| | - Vera Grinkevich
- Artios Pharma Ltd., B940 Babraham Research Campus, Cambridge CB22 3FH, UK
| | - Graeme Hewitt
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Sandra Segura-Bayona
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Roberto Bellelli
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, London EC1M 6BQ, UK
| | - Helen M R Robinson
- Artios Pharma Ltd., B940 Babraham Research Campus, Cambridge CB22 3FH, UK
| | - Geoff S Higgins
- Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Graeme C M Smith
- Artios Pharma Ltd., B940 Babraham Research Campus, Cambridge CB22 3FH, UK
| | - Stephen C West
- DNA Recombination and Repair Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - David S Rueda
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London W12 0NN, UK; Single Molecule Imaging Group, MRC-London Institute of Medical Sciences, London W12 0NN, UK
| | - Simon J Boulton
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK; Artios Pharma Ltd., B940 Babraham Research Campus, Cambridge CB22 3FH, UK.
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22
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Abstract
DNA polymerase θ (Pol θ) is a DNA repair enzyme widely conserved in animals and plants. Pol θ uses short DNA sequence homologies to initiate repair of double-strand breaks by theta-mediated end joining. The DNA polymerase domain of Pol θ is at the C terminus and is connected to an N-terminal DNA helicase-like domain by a central linker. Pol θ is crucial for maintenance of damaged genomes during development, protects DNA against extensive deletions, and limits loss of heterozygosity. The cost of using Pol θ for genome protection is that a few nucleotides are usually deleted or added at the repair site. Inactivation of Pol θ often enhances the sensitivity of cells to DNA strand-breaking chemicals and radiation. Since some homologous recombination-defective cancers depend on Pol θ for growth, inhibitors of Pol θ may be useful in treating such tumors.
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Affiliation(s)
- Richard D Wood
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, Texas, USA;
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, USA;
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23
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Vanson S, Li Y, Wood RD, Doublié S. Probing the structure and function of polymerase θ helicase-like domain. DNA Repair (Amst) 2022; 116:103358. [PMID: 35753097 PMCID: PMC10329254 DOI: 10.1016/j.dnarep.2022.103358] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/09/2022] [Accepted: 06/09/2022] [Indexed: 11/19/2022]
Abstract
DNA Polymerase θ is the key actuator of the recently identified double-strand break repair pathway, theta-mediated end joining (TMEJ). It is the only known polymerase to have a 3-domain architecture containing an independently functional family A DNA polymerase tethered by a long central region to an N-terminal helicase-like domain (HLD). Full-length polymerase θ and the isolated HLD hydrolyze ATP in the presence of DNA, but no processive DNA duplex unwinding has been observed. Based on sequence and structure conservation, the HLD is classified as a member of helicase superfamily II and, more specifically, the Ski2-like family. The specific subdomain composition and organization most closely resemble that of archaeal DNA repair helicases Hel308 and Hjm. The underlying structural basis as to why the HLD is not able to processively unwind duplex DNA, despite its similarity to bona fide helicases, remains elusive. Activities of the HLD include ATP hydrolysis, protein displacement, and annealing of complementary DNA. These observations have led to speculation about the role of the HLD within the context of double-strand break repair via TMEJ, such as removal of single-stranded DNA binding proteins like RPA and RAD51 and microhomology alignment. This review summarizes the structural classification and organization of the polymerase θ HLD and its homologs and explores emerging data on its biochemical activities. We conclude with a simple, speculative model for the HLD's role in TMEJ.
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Affiliation(s)
- Scott Vanson
- Department of Microbiology and Molecular Genetics, University of Vermont, 89 Beaumont Ave, Burlington, VT 05405, USA
| | - Yuzhen Li
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, TX 77230, USA
| | - Richard D Wood
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, TX 77230, USA.
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, 89 Beaumont Ave, Burlington, VT 05405, USA.
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