1
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Yang H, Lan L. Transcription-coupled DNA repair protects genome stability upon oxidative stress-derived DNA strand breaks. FEBS Lett 2024. [PMID: 38813713 DOI: 10.1002/1873-3468.14938] [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: 02/01/2024] [Revised: 03/27/2024] [Accepted: 04/29/2024] [Indexed: 05/31/2024]
Abstract
Elevated oxidative stress, which threatens genome stability, has been detected in almost all types of cancers. Cells employ various DNA repair pathways to cope with DNA damage induced by oxidative stress. Recently, a lot of studies have provided insights into DNA damage response upon oxidative stress, specifically in the context of transcriptionally active genomes. Here, we summarize recent studies to help understand how the transcription is regulated upon DNA double strand breaks (DSB) and how DNA repair pathways are selectively activated at the damage sites coupling with transcription. The role of RNA molecules, especially R-loops and RNA modifications during the DNA repair process, is critical for protecting genome stability. This review provides an update on how cells protect transcribed genome loci via transcription-coupled repair pathways.
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Affiliation(s)
- Haibo Yang
- Department of Urology, Brigham and Women's Hospital & Harvard Medical School, Boston, MA, USA
| | - Li Lan
- Department of Molecular Genetics and Microbiology, School of Medicine, Duke University, Durham, NC, USA
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2
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Fried W, Tyagi M, Minakhin L, Chandramouly G, Tredinnick T, Ramanjulu M, Auerbacher W, Calbert M, Rusanov T, Hoang T, Borisonnik N, Betsch R, Krais JJ, Wang Y, Vekariya UM, Gordon J, Morton G, Kent T, Skorski T, Johnson N, Childers W, Chen XS, Pomerantz RT. Discovery of a small-molecule inhibitor that traps Polθ on DNA and synergizes with PARP inhibitors. Nat Commun 2024; 15:2862. [PMID: 38580648 PMCID: PMC10997755 DOI: 10.1038/s41467-024-46593-1] [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: 08/14/2023] [Accepted: 03/04/2024] [Indexed: 04/07/2024] Open
Abstract
The DNA damage response (DDR) protein DNA Polymerase θ (Polθ) is synthetic lethal with homologous recombination (HR) factors and is therefore a promising drug target in BRCA1/2 mutant cancers. We discover an allosteric Polθ inhibitor (Polθi) class with 4-6 nM IC50 that selectively kills HR-deficient cells and acts synergistically with PARP inhibitors (PARPi) in multiple genetic backgrounds. X-ray crystallography and biochemistry reveal that Polθi selectively inhibits Polθ polymerase (Polθ-pol) in the closed conformation on B-form DNA/DNA via an induced fit mechanism. In contrast, Polθi fails to inhibit Polθ-pol catalytic activity on A-form DNA/RNA in which the enzyme binds in the open configuration. Remarkably, Polθi binding to the Polθ-pol:DNA/DNA closed complex traps the polymerase on DNA for more than forty minutes which elucidates the inhibitory mechanism of action. These data reveal a unique small-molecule DNA polymerase:DNA trapping mechanism that induces synthetic lethality in HR-deficient cells and potentiates the activity of PARPi.
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Affiliation(s)
- William Fried
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA, USA
| | - Mrityunjay Tyagi
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, 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
| | - Taylor Tredinnick
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Mercy Ramanjulu
- Recombination Therapeutics, Pennsylvania Biotechnology Center, Doylestown, PA, 18902, USA
| | - William Auerbacher
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Marissa Calbert
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA
- Fels Cancer Institute for Personalized Medicine, Philadelphia, PA, USA
| | - Timur Rusanov
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, 60612, 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
| | - Yifan Wang
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Umeshkumar M Vekariya
- Fels Cancer Institute for Personalized Medicine, Philadelphia, PA, USA
- Department of Cancer and Cellular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - John Gordon
- Fels Cancer Institute for Personalized Medicine, Philadelphia, PA, USA
| | - George Morton
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, PA, USA
| | - Tatiana Kent
- 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, Philadelphia, PA, USA
- Department of Cancer and Cellular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Neil Johnson
- Nuclear Dynamics Program, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Wayne Childers
- Recombination Therapeutics, Pennsylvania Biotechnology Center, Doylestown, PA, 18902, USA
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, PA, USA
| | - Xiaojiang S Chen
- Molecular and Computational Biology, Department of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA, USA
- Recombination Therapeutics, Pennsylvania Biotechnology Center, Doylestown, PA, 18902, USA
| | - Richard T Pomerantz
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, 19107, USA.
- Recombination Therapeutics, Pennsylvania Biotechnology Center, Doylestown, PA, 18902, USA.
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3
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Kannan S, Gillespie SW, Picking WL, Picking WD, Lorson CL, Singh K. Inhibitors against DNA Polymerase I Family of Enzymes: Novel Targets and Opportunities. BIOLOGY 2024; 13:204. [PMID: 38666816 PMCID: PMC11048162 DOI: 10.3390/biology13040204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 03/18/2024] [Accepted: 03/20/2024] [Indexed: 04/28/2024]
Abstract
DNA polymerases replicate cellular genomes and/or participate in the maintenance of genome integrity. DNA polymerases sharing high sequence homology with E. coli DNA polymerase I (pol I) have been grouped in Family A. Pol I participates in Okazaki fragment maturation and in bacterial genome repair. Since its discovery in 1956, pol I has been extensively studied, primarily to gain deeper insights into the mechanism of DNA replication. As research on DNA polymerases advances, many novel functions of this group of polymerases are being uncovered. For example, human DNA polymerase θ (a Family A DNA pol) has been shown to synthesize DNA using RNA as a template, a function typically attributed to retroviral reverse transcriptase. Increased interest in drug discovery against pol θ has emerged due to its roles in cancer. Likewise, Pol I family enzymes also appear attractive as drug-development targets against microbial infections. Development of antimalarial compounds targeting apicoplast apPOL, an ortholog of Pol I, further extends the targeting of this family of enzymes. Here, we summarize reported drug-development efforts against Family A polymerases and future perspective regarding these enzymes as antibiotic targets. Recently developed techniques, such as artificial intelligence, can be used to facilitate the development of new drugs.
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Affiliation(s)
- Saathvik Kannan
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
| | - Samuel W. Gillespie
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
| | - Wendy L. Picking
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - William D. Picking
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Christian L. Lorson
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Kamal Singh
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA; (S.K.); (S.W.G.); (W.L.P.); (W.D.P.); (C.L.L.)
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
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4
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Igyártó BZ, Qin Z. The mRNA-LNP vaccines - the good, the bad and the ugly? Front Immunol 2024; 15:1336906. [PMID: 38390323 PMCID: PMC10883065 DOI: 10.3389/fimmu.2024.1336906] [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: 11/11/2023] [Accepted: 01/23/2024] [Indexed: 02/24/2024] Open
Abstract
The mRNA-LNP vaccine has received much attention during the COVID-19 pandemic since it served as the basis of the most widely used SARS-CoV-2 vaccines in Western countries. Based on early clinical trial data, these vaccines were deemed safe and effective for all demographics. However, the latest data raise serious concerns about the safety and effectiveness of these vaccines. Here, we review some of the safety and efficacy concerns identified to date. We also discuss the potential mechanism of observed adverse events related to the use of these vaccines and whether they can be mitigated by alterations of this vaccine mechanism approach.
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Affiliation(s)
- Botond Z. Igyártó
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA, United States
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5
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Steele EJ, Franklin A, Lindley RA. Somatic mutation patterns at Ig and Non-Ig Loci. DNA Repair (Amst) 2024; 133:103607. [PMID: 38056368 DOI: 10.1016/j.dnarep.2023.103607] [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: 06/22/2023] [Revised: 11/17/2023] [Accepted: 11/21/2023] [Indexed: 12/08/2023]
Abstract
The reverse transcriptase (RT) model of immunoglobulin (Ig) somatic hypermutation (SHM) has received insufficient scientific attention. This is understandable given that DNA deamination mediated by activation-induced deaminase (AID), the initiating step of Ig SHM, has dominated experiments since 2002. We summarise some key history of the RT Ig SHM model dating to 1987. For example, it is now established that DNA polymerase η, the sole DNA repair polymerase involved in post-replication short-patch repair, is an efficient cellular RT. This implies that it is potentially able to initiate target site reverse transcription by RNA-directed DNA repair at AID-induced lesions. Recently, DNA polymerase θ has also been shown to be an efficient cellular RT. Since DNA polymerase θ plays no significant role in Ig SHM, it could serve a similar RNA-dependent DNA polymerase role as DNA polymerase η at non-Ig loci in the putative RNA-templated nucleotide excision repair of bulky adducts and other mutagenic lesions on the transcribed strand. A major yet still poorly recognised consequence of the proposed RT process in Ig SHM is the generation of significant and characteristic strand-biased mutation signatures at both deoxyadenosine/deoxythymidine and deoxyguanosine/deoxycytidine base pairs. In this historical perspective, we highlight how diagnostic strand-biased mutation signatures are detected in vivo during SHM at both Ig loci in germinal centre B lymphocytes and non-Ig loci in cancer genomes. These strand-biased signatures have been significantly obscured by technical issues created by improper use of the polymerase chain reaction technique. A heightened awareness of this fact should contribute to better data interpretation and somatic mutation pattern recognition both at Ig and non-Ig loci.
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Affiliation(s)
- Edward J Steele
- Melville Analytics Pty Ltd, 2/102 Duke St, Kangaroo Point, Brisbane 4169, Qld, Australia.
| | - Andrew Franklin
- Novartis Pharmaceuticals UK Limited, The WestWorks Building, White City Place, 195 Wood Lane, W12 7FQ London, United Kingdom
| | - Robyn A Lindley
- GMDxgenomics, Suite 201, 697 Burke Rd, Camberwell, Melbourne 3124, Vic, Australia; Department of Clinical Pathology, Faculty of Medicine, Dentistry & Health Sciences, University of Melbourne, Vic, Australia
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6
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Oscorbin IP, Filipenko ML. A Novel Thermostable and Processive Reverse Transcriptase from a Group II Intron of Anoxybacillus flavithermus. Biomolecules 2023; 14:49. [PMID: 38254649 PMCID: PMC10813441 DOI: 10.3390/biom14010049] [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: 11/06/2023] [Revised: 12/22/2023] [Accepted: 12/27/2023] [Indexed: 01/24/2024] Open
Abstract
Reverse transcriptases (RTs) are a family of enzymes that synthesize DNA using an RNA template and are involved in retrovirus propagation and telomere lengthening. In vitro, RTs are widely applied in various methods, including RNA-seq, RT-PCR, and RT-LAMP. Thermostable RTs from bacterial group II introns are promising tools for biotechnology due to their higher thermostability, fidelity, and processivity compared to commonly used M-MuLV RT and its mutants. However, the diversity of group II intron-encoded RTs is still understudied. In this work, we biochemically characterized a novel RT from a thermophilic bacterium, Anoxybacillus flavithermus, which was isolated from a hot spring in New Zealand and has an optimal growth temperature of around 60 °C. The cloned RT, named Afl RT, retained approximately 40% of the specific activity after a 45 min incubation at 50 °C. The optimal pH was 8.5, the optimal temperature was between 45 and 50 °C, and Mn2+ ions were found to be an optimal cofactor. The processivity analysis with MS2 phage gRNA (3569 b) demonstrated that Afl RT elongated fully up to 36% of the template molecules. In reverse transcription and RT-qLAMP, the enzyme allowed up to 10 copies of MS2 phage genomic RNA to be detected per reaction. Thus, Afl RT holds great potential for a variety of practical applications that require the use of thermostable and processive RTs.
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Affiliation(s)
- Igor P. Oscorbin
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences (ICBFM SB RAS), 8 Lavrentiev Avenue, 630090 Novosibirsk, Russia;
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7
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Mendez-Dorantes C, Burns KH. LINE-1 retrotransposition and its deregulation in cancers: implications for therapeutic opportunities. Genes Dev 2023; 37:948-967. [PMID: 38092519 PMCID: PMC10760644 DOI: 10.1101/gad.351051.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Long interspersed element 1 (LINE-1) is the only protein-coding transposon that is active in humans. LINE-1 propagates in the genome using RNA intermediates via retrotransposition. This activity has resulted in LINE-1 sequences occupying approximately one-fifth of our genome. Although most copies of LINE-1 are immobile, ∼100 copies are retrotransposition-competent. Retrotransposition is normally limited via epigenetic silencing, DNA repair, and other host defense mechanisms. In contrast, LINE-1 overexpression and retrotransposition are hallmarks of cancers. Here, we review mechanisms of LINE-1 regulation and how LINE-1 may promote genetic heterogeneity in tumors. Finally, we discuss therapeutic strategies to exploit LINE-1 biology in cancers.
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Affiliation(s)
- Carlos Mendez-Dorantes
- Department of Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA;
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
| | - Kathleen H Burns
- Department of Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA;
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
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8
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Bader AS, Bushell M. iMUT-seq: high-resolution DSB-induced mutation profiling reveals prevalent homologous-recombination dependent mutagenesis. Nat Commun 2023; 14:8419. [PMID: 38110444 PMCID: PMC10728174 DOI: 10.1038/s41467-023-44167-1] [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: 04/01/2022] [Accepted: 12/04/2023] [Indexed: 12/20/2023] Open
Abstract
DNA double-strand breaks (DSBs) are the most mutagenic form of DNA damage, and play a significant role in cancer biology, neurodegeneration and aging. However, studying DSB-induced mutagenesis is limited by our current approaches. Here, we describe iMUT-seq, a technique that profiles DSB-induced mutations at high-sensitivity and single-nucleotide resolution around endogenous DSBs. By depleting or inhibiting 20 DSB-repair factors we define their mutational signatures in detail, revealing insights into the mechanisms of DSB-induced mutagenesis. Notably, we find that homologous-recombination (HR) is more mutagenic than previously thought, inducing prevalent base substitutions and mononucleotide deletions at distance from the break due to DNA-polymerase errors. Simultaneously, HR reduces translocations, suggesting a primary role of HR is specifically the prevention of genomic rearrangements. The results presented here offer fundamental insights into DSB-induced mutagenesis and have significant implications for our understanding of cancer biology and the development of DDR-targeting chemotherapeutics.
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Affiliation(s)
- Aldo S Bader
- Cancer Research UK Beatson Institute, Glasgow, G61 1BD, UK.
- Cancer Research UK/CI, University of Cambridge, Li Ka Shing Centre, Cambridge, CB2 0RE, UK.
- The Gurdon Institute, University of Cambridge, Biochemistry, Cambridge, UK.
| | - Martin Bushell
- Cancer Research UK Beatson Institute, Glasgow, G61 1BD, UK.
- Institute of Cancer Sciences, University of Glasgow, Glasgow, G61 1QH, UK.
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9
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Tozzi A, Mazzeo M. The First Nucleic Acid Strands May Have Grown on Peptides via Primeval Reverse Translation. Acta Biotheor 2023; 71:23. [PMID: 37947915 DOI: 10.1007/s10441-023-09474-6] [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: 04/05/2023] [Accepted: 10/25/2023] [Indexed: 11/12/2023]
Abstract
The central dogma of molecular biology dictates that, with only a few exceptions, information proceeds from DNA to protein through an RNA intermediate. Examining the enigmatic steps from prebiotic to biological chemistry, we take another road suggesting that primordial peptides acted as template for the self-assembly of the first nucleic acids polymers. Arguing in favour of a sort of archaic "reverse translation" from proteins to RNA, our basic premise is a Hadean Earth where key biomolecules such as amino acids, polypeptides, purines, pyrimidines, nucleosides and nucleotides were available under different prebiotically plausible conditions, including meteorites delivery, shallow ponds and hydrothermal vents scenarios. Supporting a protein-first scenario alternative to the RNA world hypothesis, we propose the primeval occurrence of short two-dimensional peptides termed "selective amino acid- and nucleotide-matching oligopeptides" (henceforward SANMAOs) that noncovalently bind at the same time the polymerized amino acids and the single nucleotides dispersed in the prebiotic milieu. In this theoretical paper, we describe the chemical features of this hypothetical oligopeptide, its biological plausibility and its virtues from an evolutionary perspective. We provide a theoretical example of SANMAO's selective pairing between amino acids and nucleosides, simulating a poly-Glycine peptide that acts as a template to build a purinic chain corresponding to the glycine's extant triplet codon GGG. Further, we discuss how SANMAO might have endorsed the formation of low-fidelity RNA's polymerized strains, well before the appearance of the accurate genetic material's transmission ensured by the current translation apparatus.
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Affiliation(s)
- Arturo Tozzi
- Center for Nonlinear Science, Department of Physics, University of North Texas, 1155 Union Circle, #311427, Denton, TX, 76203-5017, USA.
| | - Marco Mazzeo
- Erredibi Srl, Via Pazzigno 117, 80146, Naples, Italy
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10
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Lakota J. Spontaneous regression of tumours. Possible cross reactivity of autoantibodies against carbonic anhydrase I. J Cell Mol Med 2023; 27:3637-3640. [PMID: 37776059 PMCID: PMC10660616 DOI: 10.1111/jcmm.17970] [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: 06/28/2023] [Revised: 09/11/2023] [Accepted: 09/16/2023] [Indexed: 10/01/2023] Open
Abstract
Spontaneous tumour regression in patients after high dose therapy and autologous stem cell transplantation or patients with standard therapy is accompanied with the presence of high titers autoantibodies against carbonic anhydrase I (CA I). The concomitant presence of aplastic anaemia-like syndrome in these patients points to parallel bone marrow suppression during this period. It seems that CA I, an 'obscure' enzyme, does not have any significant physiological role in humans. One possible explanation points to the fact that autoantibodies against CA I may target another antigen(s) which is(are) important in tumour growth as well as in normal haematopoiesis. One of the candidates for such a target is the DNA polymerase theta.
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Affiliation(s)
- Ján Lakota
- Centre of Experimental Medicine, SASBratislavaSlovakia
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11
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Paniagua I, Jacobs JJL. Freedom to err: The expanding cellular functions of translesion DNA polymerases. Mol Cell 2023; 83:3608-3621. [PMID: 37625405 DOI: 10.1016/j.molcel.2023.07.008] [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: 02/24/2023] [Revised: 06/02/2023] [Accepted: 07/07/2023] [Indexed: 08/27/2023]
Abstract
Translesion synthesis (TLS) DNA polymerases were originally described as error-prone enzymes involved in the bypass of DNA lesions. However, extensive research over the past few decades has revealed that these enzymes play pivotal roles not only in lesion bypass, but also in a myriad of other cellular processes. Such processes include DNA replication, DNA repair, epigenetics, immune signaling, and even viral infection. This review discusses the wide range of functions exhibited by TLS polymerases, including their underlying biochemical mechanisms and associated mutagenicity. Given their multitasking ability to alleviate replication stress, TLS polymerases represent a cellular dependency and a critical vulnerability of cancer cells. Hence, this review also highlights current and emerging strategies for targeting TLS polymerases in cancer therapy.
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Affiliation(s)
- Inés Paniagua
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Jacqueline J L Jacobs
- Division of Oncogenomics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands.
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12
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Palovcak A, Yuan F, Verdun R, Luo L, Zhang Y. Fanconi anemia associated protein 20 (FAAP20) plays an essential role in homology-directed repair of DNA double-strand breaks. Commun Biol 2023; 6:873. [PMID: 37620397 PMCID: PMC10449828 DOI: 10.1038/s42003-023-05252-9] [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: 12/19/2022] [Accepted: 08/17/2023] [Indexed: 08/26/2023] Open
Abstract
FAAP20 is a Fanconi anemia (FA) protein that associates with the FA core complex to promote FANCD2/FANCI monoubiquitination and activate the damage response to interstrand crosslink damage. Here, we report that FAAP20 has a marked role in homologous recombination at a DNA double-strand break not associated with an ICL and separable from its binding partner FANCA. While FAAP20's role in homologous recombination is not dependent on FANCA, we found that FAAP20 stimulates FANCA's biochemical activity in vitro and participates in the single-strand annealing pathway of double-strand break repair in a FANCA-dependent manner. This indicates that FAAP20 has roles in several homology-directed repair pathways. Like other homology-directed repair factors, FAAP20 loss causes a reduction in nuclear RAD51 Irradiation-induced foci; and sensitizes cancer cells to ionizing radiation and PARP inhibition. In summary, FAAP20 participates in DNA double strand break repair by supporting homologous recombination in a non-redundant manner to FANCA, and single-strand annealing repair via FANCA-mediated strand annealing activity.
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Affiliation(s)
- Anna Palovcak
- Department of Biochemistry & Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Fenghua Yuan
- Department of Biochemistry & Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Ramiro Verdun
- Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Liang Luo
- Department of Biochemistry & Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Yanbin Zhang
- Department of Biochemistry & Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
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13
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Miller WB, Baluška F, Reber AS. A revised central dogma for the 21st century:all biology is cognitive information processing. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023:S0079-6107(23)00057-3. [PMID: 37268025 DOI: 10.1016/j.pbiomolbio.2023.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/28/2023] [Accepted: 05/30/2023] [Indexed: 06/04/2023]
Abstract
Crick's Central Dogma has been a foundational aspect of 20th century biology, describing an implicit relationship governing the flow of information in biological systems in biomolecular terms. Accumulating scientific discoveries support the need for a revised Central Dogma to buttress evolutionary biology's still-fledgling migration from a Neodarwinian canon. A reformulated Central Dogma to meet contemporary biology is proposed: all biology is cognitive information processing. Central to this contention is the recognition that life is the self-referential state, instantiated within the cellular form. Self-referential cells act to sustain themselves and to do so, cells must be in consistent harmony with their environment. That consonance is achieved by the continuous assimilation of environmental cues and stresses as information to self-referential observers. All received cellular information must be analyzed to be deployed as cellular problem-solving to maintain homeorhetic equipoise. However, the effective implementation of information is definitively a function of orderly information management. Consequently, effective cellular problem-solving is information processing and management. The epicenter of that cellular information processing is its self-referential internal measurement. All further biological self-organization initiates from this obligate activity. As the internal measurement by cells of information is self-referential by definition, self-reference is biological self-organization, underpinning 21st century Cognition-Based Biology.
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Affiliation(s)
| | | | - Arthur S Reber
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada.
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14
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Tschage L, Kowarz E, Marschalek R. Model System to Analyze RNA-Mediated DNA Repair in Mammalian Cells. CRISPR J 2023. [PMID: 37200486 DOI: 10.1089/crispr.2022.0105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023] Open
Abstract
"RNA-templated/directed DNA repair" is a biological mechanism that has been experimentally demonstrated in bacteria, yeast, and mammalian cells. Recent study has shown that small noncoding RNAs (DDRNAs) and/or newly RNAPII transcribed RNAs (dilncRNAs) are orchestrating the initial steps of double-strand break (DSB) repair. In this study, we demonstrate that also pre-mRNA could be used as direct or indirect substrate for DSB repair. Our test system is based on (1) a stably integrated mutant reporter gene that produces constitutively a nonspliceable pre-mRNA, (2) a transiently expressed sgRNA-guided dCas13b::ADAR fusion protein to specifically RNA edit the nonspliceable pre-mRNA, and (3) transiently expressed I-SceI to create a DSB situation to study the effect of spliceable pre-mRNA on DNA repair. Based on our data, the RNA-edited pre-mRNA was used in cis for the DSB repair process, thereby converting the genomically encoded mutant reporter gene into an active reporter gene. Overexpression and knockdown of several cellular proteins were performed to delineate their role in this novel "RNA-mediated end joining" pathway.
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Affiliation(s)
- Lisa Tschage
- Institute of Pharmaceutical Biology, Goethe-University, Frankfurt am Main, Germany
| | - Eric Kowarz
- Institute of Pharmaceutical Biology, Goethe-University, Frankfurt am Main, Germany
| | - Rolf Marschalek
- Institute of Pharmaceutical Biology, Goethe-University, Frankfurt am Main, Germany
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15
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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: 0] [Impact Index Per Article: 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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16
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Apari P, Földvári G. Domestication and microbiome succession may drive pathogen spillover. Front Microbiol 2023; 14:1102337. [PMID: 37007505 PMCID: PMC10065160 DOI: 10.3389/fmicb.2023.1102337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 03/02/2023] [Indexed: 03/19/2023] Open
Abstract
Emerging infectious diseases have posed growing medical, social and economic threats to humanity. The biological background of pathogen spillover or host switch, however, still has to be clarified. Disease ecology finds pathogen spillovers frequently but struggles to explain at the molecular level. Contrarily, molecular biological traits of host-pathogen relationships with specific molecular binding mechanisms predict few spillovers. Here we aim to provide a synthetic explanation by arguing that domestication, horizontal gene transfer even between superkingdoms as well as gradual exchange of microbiome (microbiome succession) are essential in the whole scenario. We present a new perspective at the molecular level which can explain the observations of frequent pathogen spillover events at the ecological level. This proposed rationale is described in detail, along with supporting evidence from the peer-reviewed literature and suggestions for testing hypothesis validity. We also highlight the importance of systematic monitoring of virulence genes across taxonomical categories and in the whole biosphere as it helps prevent future epidemics and pandemics. We conclude that that the processes of domestication, horizontal gene transfer and microbial succession might be important mechanisms behind the many spillover events driven and accelerated by climate change, biodiversity loss and globalization.
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Affiliation(s)
- Péter Apari
- Institute of Evolution, Centre for Ecological Research, Budapest, Hungary
| | - Gábor Földvári
- Institute of Evolution, Centre for Ecological Research, Budapest, Hungary
- Centre for Eco-Epidemiology, National Laboratory for Health Security, Budapest, Hungary
- *Correspondence: Gábor Földvári,
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17
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Balboni B, Rinaldi F, Previtali V, Ciamarone A, Girotto S, Cavalli A. Novel Insights into RAD52’s Structure, Function, and Druggability for Synthetic Lethality and Innovative Anticancer Therapies. Cancers (Basel) 2023; 15:cancers15061817. [PMID: 36980703 PMCID: PMC10046612 DOI: 10.3390/cancers15061817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/08/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023] Open
Abstract
In recent years, the RAD52 protein has been highlighted as a mediator of many DNA repair mechanisms. While RAD52 was initially considered to be a non-essential auxiliary factor, its inhibition has more recently been demonstrated to be synthetically lethal in cancer cells bearing mutations and inactivation of specific intracellular pathways, such as homologous recombination. RAD52 is now recognized as a novel and critical pharmacological target. In this review, we comprehensively describe the available structural and functional information on RAD52. The review highlights the pathways in which RAD52 is involved and the approaches to RAD52 inhibition. We discuss the multifaceted role of this protein, which has a complex, dynamic, and functional 3D superstructural arrangement. This complexity reinforces the need to further investigate and characterize RAD52 to solve a challenging mechanistic puzzle and pave the way for a robust drug discovery campaign.
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Affiliation(s)
- Beatrice Balboni
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, via Belmeloro 6, 40126 Bologna, Italy
| | - Francesco Rinaldi
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, via Belmeloro 6, 40126 Bologna, Italy
| | - Viola Previtali
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
| | - Andrea Ciamarone
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, via Belmeloro 6, 40126 Bologna, Italy
| | - Stefania Girotto
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
- Structural Biophysics and Translational Pharmacology Facility, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
- Correspondence: (S.G.); (A.C.); Tel.: +39-010-2896-983 (S.G.); +39-010-2897-403 (A.C.)
| | - Andrea Cavalli
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, via Belmeloro 6, 40126 Bologna, Italy
- Correspondence: (S.G.); (A.C.); Tel.: +39-010-2896-983 (S.G.); +39-010-2897-403 (A.C.)
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18
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Evolutionary honing in and mutational replacement: how long-term directed mutational responses to specific environmental pressures are possible. Theory Biosci 2023; 142:87-105. [PMID: 36899155 DOI: 10.1007/s12064-023-00387-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 01/13/2023] [Indexed: 03/12/2023]
Abstract
Recent results have shown that the human malaria-resistant hemoglobin S mutation originates de novo more frequently in the gene and in the population where it is of adaptive significance, namely, in the hemoglobin subunit beta gene compared to the nonresistant but otherwise identical 20A[Formula: see text]T mutation in the hemoglobin subunit delta gene, and in sub-Saharan Africans, who have been subject to intense malarial pressure for many generations, compared to northern Europeans, who have not. This finding raises a fundamental challenge to the traditional notion of accidental mutation. Here, we address this finding with the replacement hypothesis, according to which preexisting genetic interactions can lead directly and mechanistically to mutations that simplify and replace them. Thus, an evolutionary process under selection can gradually hone in on interactions of importance for the currently evolving adaptations, from which large-effect mutations follow that are relevant to these adaptations. We exemplify this hypothesis using multiple types of mutation, including gene fusion mutations, gene duplication mutations, A[Formula: see text]G mutations in RNA-edited sites and transcription-associated mutations, and place it in the broader context of a system-level view of mutation origination called interaction-based evolution. Potential consequences include that similarity of mutation pressures may contribute to parallel evolution in genetically related species, that the evolution of genome organization may be driven by mutational mechanisms, that transposable element movements may also be explained by replacement, and that long-term directed mutational responses to specific environmental pressures are possible. Such mutational phenomena need to be further tested by future studies in natural and artificial settings.
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19
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Chakraborty A, Tapryal N, Islam A, Sarker AH, Manohar K, Mitra J, Hegde ML, Hazra T. Human DNA polymerase η promotes RNA-templated error-free repair of DNA double-strand breaks. J Biol Chem 2023; 299:102991. [PMID: 36758800 PMCID: PMC10011834 DOI: 10.1016/j.jbc.2023.102991] [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: 10/06/2022] [Revised: 01/20/2023] [Accepted: 01/31/2023] [Indexed: 02/10/2023] Open
Abstract
A growing body of evidence indicates that RNA plays a critical role in orchestrating DNA double-strand break repair (DSBR). Recently, we showed that homologous nascent RNA can be used as a template for error-free repair of double-strand breaks (DSBs) in the transcribed genome and to restore the missing sequence at the break site via the transcription-coupled classical nonhomologous end-joining (TC-NHEJ) pathway. TC-NHEJ is a complex multistep process in which a reverse transcriptase (RT) is essential for synthesizing the DNA strand from template RNA. However, the identity of the RT involved in the TC-NHEJ pathway remained unknown. Here, we report that DNA polymerase eta (Pol η), known to possess RT activity, plays a critical role in TC-NHEJ. We found that Pol η forms a multiprotein complex with RNAP II and other TC-NHEJ factors, while also associating with nascent RNA. Moreover, purified Pol η, along with DSBR proteins PNKP, XRCC4, and Ligase IV can fully repair RNA templated 3'-phosphate-containing gapped DNA substrate. In addition, we demonstrate here that Pol η deficiency leads to accumulation of R-loops and persistent strand breaks in the transcribed genes. Finally, we determined that, in Pol η depleted but not in control cells, TC-NHEJ-mediated repair was severely abrogated when a reporter plasmid containing a DSB with several nucleotide deletion within the E. coli lacZ gene was introduced for repair in lacZ-expressing mammalian cells. Thus, our data strongly suggest that RT activity of Pol η is required in error-free DSBR.
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Affiliation(s)
- Anirban Chakraborty
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA
| | - Nisha Tapryal
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA
| | - Azharul Islam
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA
| | - Altaf H Sarker
- Life Sciences Division, Department of Cancer and DNA Damage Responses, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Kodavati Manohar
- Department of Neurosurgery, Center for Neuroregeneration, The Houston Methodist Research Institute, Houston, Texas, USA
| | - Joy Mitra
- Department of Neurosurgery, Center for Neuroregeneration, The Houston Methodist Research Institute, Houston, Texas, USA
| | - Muralidhar L Hegde
- Department of Neurosurgery, Center for Neuroregeneration, The Houston Methodist Research Institute, Houston, Texas, USA
| | - Tapas Hazra
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA.
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20
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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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21
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Patterson-Fortin J, D'Andrea AD. Targeting Polymerase Theta (POLθ) for Cancer Therapy. Cancer Treat Res 2023; 186:285-298. [PMID: 37978141 DOI: 10.1007/978-3-031-30065-3_15] [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] [Indexed: 11/19/2023]
Abstract
Polymerase theta (POLθ) is the critical multi-domain enzyme in microhomology-mediated end-joining DNA double-stranded break repair. POLθ is expressed at low levels in normal tissue but is often overexpressed in cancers, especially in DNA repair deficient cancers, such as homologous-recombination cancers, rendering them exquisitely sensitive to POLθ inhibition secondary to synthetic lethality. Development of POLθ inhibitors is an active area of investigation with inhibitors of the N-terminal helicase domain or the C-terminal polymerase domain currently in clinical trial. Here, we review POLθ-mediated microhomology-mediated end-joining, the development of POLθ inhibitors, and the potential clinical uses of POLθ inhibitors.
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Affiliation(s)
- Jeffrey Patterson-Fortin
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - Alan D D'Andrea
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.
- Harvard Medical School, Center for DNA Damage and Repair, Susan F. Smith Center for Women's Cancers (SFSCWC), The Fuller-American Cancer Society, Dana-Farber Cancer Institute, HIM 243, 450 Brookline Ave., Boston, MA, 02215, USA.
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22
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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 2022; 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] [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)
| | | | - 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
- Correspondence may also be addressed to Ji Sun.
| | - Yang Gao
- To whom correspondence should be addressed. Tel: +1 713 348 2619;
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23
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Tsegay PS, Hernandez D, Qu F, Olatunji M, Mamun Y, Chapagain P, Liu Y. RNA-guided DNA base damage repair via DNA polymerase-mediated nick translation. Nucleic Acids Res 2022; 51:166-181. [PMID: 36533524 PMCID: PMC9841414 DOI: 10.1093/nar/gkac1178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/28/2022] [Accepted: 12/06/2022] [Indexed: 12/23/2022] Open
Abstract
DNA repair is mediated by DNA synthesis guided by a DNA template. Recent studies have shown that DNA repair can also be accomplished by RNA-guided DNA synthesis. However, it remains unknown how RNA can guide DNA synthesis to repair DNA damage. In this study, we revealed the molecular mechanisms underlying RNA-guided DNA synthesis and base damage repair mediated by human repair DNA polymerases. We showed that pol β, pol κ, and pol ι predominantly synthesized one nucleotide, and pol η, pol ν, and pol θ synthesized multi-nucleotides during RNA-guided DNA base damage repair. The steady-state kinetics showed that pol η exhibited more efficient RNA-guided DNA synthesis than pol β. Using molecular dynamics simulation, we further revealed dynamic conformational changes of pol β and pol η and their structural basis to accommodate the RNA template and misoriented triphosphates of an incoming nucleotide. We demonstrated that RNA-guided base damage repair could be accomplished by the RNA-guided DNA strand-displacement synthesis and nick translation leading to nick ligation in a double-strand DNA region. Our study revealed a novel RNA-guided base damage repair pathway during transcription and DNA replication.
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Affiliation(s)
- Pawlos S Tsegay
- Biochemistry Ph.D. Program, Florida International University, Miami, FL, USA
| | - Daniela Hernandez
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA
| | - Fei Qu
- Biochemistry Ph.D. Program, Florida International University, Miami, FL, USA
| | - Mustapha Olatunji
- Biochemistry Ph.D. Program, Florida International University, Miami, FL, USA
| | - Yasir Mamun
- Biochemistry Ph.D. Program, Florida International University, Miami, FL, USA
| | - Prem Chapagain
- Department of Physics, Florida International University, Miami, FL, USA,Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Yuan Liu
- To whom correspondence should be addressed. Tel: +1 305 348 3628; Fax: +1 305 348 2772;
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24
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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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25
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Stockley ML, Ferdinand A, Benedetti G, Blencowe P, Boyd SM, Calder M, Charles MD, Edwardes LV, Ekwuru T, Finch H, Galbiati A, Geo L, Grande D, Grinkevich V, Holliday ND, Krajewski WW, MacDonald E, Majithiya JB, McCarron H, McWhirter CL, Patel V, Pedder C, Rajendra E, Ranzani M, Rigoreau LJM, Robinson HMR, Schaedler T, Sirina J, Smith GCM, Swarbrick ME, Turnbull AP, Willis S, Heald RA. Discovery, Characterization, and Structure-Based Optimization of Small-Molecule In Vitro and In Vivo Probes for Human DNA Polymerase Theta. J Med Chem 2022; 65:13879-13891. [PMID: 36200480 DOI: 10.1021/acs.jmedchem.2c01142] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human DNA polymerase theta (Polθ), which is essential for microhomology-mediated DNA double strand break repair, has been proposed as an attractive target for the treatment of BRCA deficient and other DNA repair pathway defective cancers. As previously reported, we recently identified the first selective small molecule Polθ in vitro probe, 22 (ART558), which recapitulates the phenotype of Polθ loss, and in vivo probe, 43 (ART812), which is efficacious in a model of PARP inhibitor resistant TNBC in vivo. Here we describe the discovery, biochemical and biophysical characterization of these probes including small molecule ligand co-crystal structures with Polθ. The crystallographic data provides a basis for understanding the unique mechanism of inhibition of these compounds which is dependent on stabilization of a "closed" enzyme conformation. Additionally, the structural biology platform provided a basis for rational optimization based primarily on reduced ligand conformational flexibility.
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Affiliation(s)
- Martin L Stockley
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | - Amanda Ferdinand
- Cancer Research Horizons Therapeutic Innovation, Jonas Webb Building, Babraham Research Campus, CambridgeCB22 3AT, U. K
| | - Giovanni Benedetti
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | - Peter Blencowe
- Cancer Research Horizons Therapeutic Innovation, Jonas Webb Building, Babraham Research Campus, CambridgeCB22 3AT, U. K
| | - Susan M Boyd
- CompChem Solutions Ltd, St John's Innovation Centre, Cowley Rd, CambridgeCB4 0WS, U. K
| | - Mat Calder
- Cancer Research Horizons Therapeutic Innovation, Jonas Webb Building, Babraham Research Campus, CambridgeCB22 3AT, U. K
| | - Mark D Charles
- Cancer Research Horizons Therapeutic Innovation, Jonas Webb Building, Babraham Research Campus, CambridgeCB22 3AT, U. K
| | - Lucy V Edwardes
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | - Tennyson Ekwuru
- Cancer Research Horizons Therapeutic Innovation, Jonas Webb Building, Babraham Research Campus, CambridgeCB22 3AT, U. K
| | - Harry Finch
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | | | - Lerin Geo
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | - Diego Grande
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | - Vera Grinkevich
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | - Nicholas D Holliday
- Excellerate Bioscience Ltd., BioCity, Pennyfoot Street, NottinghamNG1 1GF, U. K
| | - Wojciech W Krajewski
- Cancer Research Horizons Therapeutic Innovation, The Francis Crick Institute, 1 Midland Road, LondonNW1 1AT, U. K
| | - Ellen MacDonald
- Cancer Research Horizons Therapeutic Innovation, Jonas Webb Building, Babraham Research Campus, CambridgeCB22 3AT, U. K
| | - Jayesh B Majithiya
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | - Hollie McCarron
- Cancer Research Horizons Therapeutic Innovation, Jonas Webb Building, Babraham Research Campus, CambridgeCB22 3AT, U. K
| | - Claire L McWhirter
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | - Viral Patel
- Excellerate Bioscience Ltd., BioCity, Pennyfoot Street, NottinghamNG1 1GF, U. K
| | - Chris Pedder
- Cancer Research Horizons Therapeutic Innovation, Jonas Webb Building, Babraham Research Campus, CambridgeCB22 3AT, U. K
| | - Eeson Rajendra
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | - Marco Ranzani
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | - Laurent J M Rigoreau
- Cancer Research Horizons Therapeutic Innovation, Jonas Webb Building, Babraham Research Campus, CambridgeCB22 3AT, U. K
| | - Helen M R Robinson
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | - Theresia Schaedler
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | - Julija Sirina
- Excellerate Bioscience Ltd., BioCity, Pennyfoot Street, NottinghamNG1 1GF, U. K
| | - Graeme C M Smith
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
| | - Martin E Swarbrick
- Cancer Research Horizons Therapeutic Innovation, Jonas Webb Building, Babraham Research Campus, CambridgeCB22 3AT, U. K
| | - Andrew P Turnbull
- Cancer Research Horizons Therapeutic Innovation, The Francis Crick Institute, 1 Midland Road, LondonNW1 1AT, U. K
| | - Simon Willis
- Cancer Research Horizons Therapeutic Innovation, The Francis Crick Institute, 1 Midland Road, LondonNW1 1AT, U. K
| | - Robert A Heald
- Artios Pharma Ltd., B940, Babraham Research Campus, CambridgeCB22 3FH, U. K
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26
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Bubenik M, Mader P, Mochirian P, Vallée F, Clark J, Truchon JF, Perryman AL, Pau V, Kurinov I, Zahn KE, Leclaire ME, Papp R, Mathieu MC, Hamel M, Duffy NM, Godbout C, Casas-Selves M, Falgueyret JP, Baruah PS, Nicolas O, Stocco R, Poirier H, Martino G, Fortin AB, Roulston A, Chefson A, Dorich S, St-Onge M, Patel P, Pellerin C, Ciblat S, Pinter T, Barabé F, Bakkouri ME, Parikh P, Gervais C, Sfeir A, Mamane Y, Morris SJ, Black WC, Sicheri F, Gallant M. Identification of RP-6685, an Orally Bioavailable Compound that Inhibits the DNA Polymerase Activity of Polθ. J Med Chem 2022; 65:13198-13215. [PMID: 36126059 PMCID: PMC9942948 DOI: 10.1021/acs.jmedchem.2c00998] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
DNA polymerase theta (Polθ) is an attractive synthetic lethal target for drug discovery, predicted to be efficacious against breast and ovarian cancers harboring BRCA-mutant alleles. Here, we describe our hit-to-lead efforts in search of a selective inhibitor of human Polθ (encoded by POLQ). A high-throughput screening campaign of 350,000 compounds identified an 11 micromolar hit, giving rise to the N2-substituted fused pyrazolo series, which was validated by biophysical methods. Structure-based drug design efforts along with optimization of cellular potency and ADME ultimately led to the identification of RP-6685: a potent, selective, and orally bioavailable Polθ inhibitor that showed in vivo efficacy in an HCT116 BRCA2-/- mouse tumor xenograft model.
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Affiliation(s)
- Monica Bubenik
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Pavel Mader
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, M5G 1X5, Canada
| | - Philippe Mochirian
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Fréderic Vallée
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Jillian Clark
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Jean-François Truchon
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Alexander L. Perryman
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Victor Pau
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, M5G 1X5, Canada
| | - Igor Kurinov
- Department of Chemistry and Chemical Biology, Cornell University, NE-CAT, Argonne, Illinois 60439, USA
| | - Karl E. Zahn
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Marie-Eve Leclaire
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Robert Papp
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Marie-Claude Mathieu
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Martine Hamel
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Nicole M. Duffy
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Claude Godbout
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Matias Casas-Selves
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Jean-Pierre Falgueyret
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Prasamit S. Baruah
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Olivier Nicolas
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Rino Stocco
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Hugo Poirier
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Giovanni Martino
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | | | - Anne Roulston
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Amandine Chefson
- Ventus Therapeutics 7150 Frederick-Banting suite 200, Montréal, Québec, H4S 2A1, Canada
| | - Stéphane Dorich
- Ventus Therapeutics 7150 Frederick-Banting suite 200, Montréal, Québec, H4S 2A1, Canada
| | - Miguel St-Onge
- Ventus Therapeutics 7150 Frederick-Banting suite 200, Montréal, Québec, H4S 2A1, Canada
| | - Purvish Patel
- Ventus Therapeutics 7150 Frederick-Banting suite 200, Montréal, Québec, H4S 2A1, Canada
| | - Charles Pellerin
- Ventus Therapeutics 7150 Frederick-Banting suite 200, Montréal, Québec, H4S 2A1, Canada
| | - Stéphane Ciblat
- Ventus Therapeutics 7150 Frederick-Banting suite 200, Montréal, Québec, H4S 2A1, Canada
- Paraza Pharma Inc., 2525 Ave. Marie Curie, Montréal, Québec, H4S 1Z9, Canada
| | - Thomas Pinter
- Paraza Pharma Inc., 2525 Ave. Marie Curie, Montréal, Québec, H4S 1Z9, Canada
| | - Francis Barabé
- Paraza Pharma Inc., 2525 Ave. Marie Curie, Montréal, Québec, H4S 1Z9, Canada
| | - Majida El Bakkouri
- Paraza Pharma Inc., 2525 Ave. Marie Curie, Montréal, Québec, H4S 1Z9, Canada
- National Research Council of Canada, 6100 Royalmount Ave, Montréal, Québec, H4P 2R2, Canada
| | - Paranjay Parikh
- Piramal Pharma Ltd., Plot No. 18, Village Matoda, Taluka: Sanand, Ahmedabad-382213, Gujarat, India
| | - Christian Gervais
- National Research Council of Canada, 6100 Royalmount Ave, Montréal, Québec, H4P 2R2, Canada
| | - Agnel Sfeir
- Molecular Biology Program, Sloan Kettering Institute, MSKCC, 430 E 67th Street, New York, NY 10065, USA
| | - Yael Mamane
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Stephen J. Morris
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - W. Cameron Black
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
| | - Frank Sicheri
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, M5G 1X5, Canada
| | - Michel Gallant
- Repare Therapeutics, 7171 Frederick-Banting, Building 2, H4S 1Z9, Montréal, Québec, Canada
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Moran JV, Wilson TE. Reverse transcriptase meets DNA, again: Possible roles for transposable elements in host DNA repair. Cell 2022; 185:3643-3645. [PMID: 36179663 DOI: 10.1016/j.cell.2022.09.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/05/2022] [Accepted: 09/06/2022] [Indexed: 01/26/2023]
Abstract
Retrotransposons are selfish genetic elements that encode an enzyme, reverse transcriptase (RT), which converts the element-encoded RNA into DNA prior to or during genomic integration. New studies provide compelling evidence that a bacterial group II intron-like RT has adapted enzymatic activities associated with RTs to function in host DNA repair.
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Affiliation(s)
- John V Moran
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA; Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Thomas E Wilson
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA; Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA.
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Park SK, Mohr G, Yao J, Russell R, Lambowitz AM. Group II intron-like reverse transcriptases function in double-strand break repair. Cell 2022; 185:3671-3688.e23. [PMID: 36113466 PMCID: PMC9530004 DOI: 10.1016/j.cell.2022.08.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 06/16/2022] [Accepted: 08/14/2022] [Indexed: 01/26/2023]
Abstract
Bacteria encode reverse transcriptases (RTs) of unknown function that are closely related to group II intron-encoded RTs. We found that a Pseudomonas aeruginosa group II intron-like RT (G2L4 RT) with YIDD instead of YADD at its active site functions in DNA repair in its native host and when expressed in Escherichia coli. G2L4 RT has biochemical activities strikingly similar to those of human DNA repair polymerase θ and uses them for translesion DNA synthesis and double-strand break repair (DSBR) via microhomology-mediated end-joining (MMEJ). We also found that a group II intron RT can function similarly in DNA repair, with reciprocal active-site substitutions showing isoleucine favors MMEJ and alanine favors primer extension in both enzymes. These DNA repair functions utilize conserved structural features of non-LTR-retroelement RTs, including human LINE-1 and other eukaryotic non-LTR-retrotransposon RTs, suggesting such enzymes may have inherent ability to function in DSBR in a wide range of organisms.
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Affiliation(s)
- Seung Kuk Park
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712, USA
| | - Georg Mohr
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712, USA
| | - Jun Yao
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712, USA
| | - Rick Russell
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712, USA
| | - Alan M Lambowitz
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712, USA.
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29
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Liddiard K, Aston-Evans AN, Cleal K, Hendrickson E, Baird D. POLQ suppresses genome instability and alterations in DNA repeat tract lengths. NAR Cancer 2022; 4:zcac020. [PMID: 35774233 PMCID: PMC9241439 DOI: 10.1093/narcan/zcac020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/19/2022] [Accepted: 06/10/2022] [Indexed: 11/26/2022] Open
Abstract
DNA polymerase theta (POLQ) is a principal component of the alternative non-homologous end-joining (ANHEJ) DNA repair pathway that ligates DNA double-strand breaks. Utilizing independent models of POLQ insufficiency during telomere-driven crisis, we found that POLQ - /- cells are resistant to crisis-induced growth deceleration despite sustaining inter-chromosomal telomere fusion frequencies equivalent to wild-type (WT) cells. We recorded longer telomeres in POLQ - / - than WT cells pre- and post-crisis, notwithstanding elevated total telomere erosion and fusion rates. POLQ - /- cells emerging from crisis exhibited reduced incidence of clonal gross chromosomal abnormalities in accordance with increased genetic heterogeneity. High-throughput sequencing of telomere fusion amplicons from POLQ-deficient cells revealed significantly raised frequencies of inter-chromosomal fusions with correspondingly depreciated intra-chromosomal recombinations. Long-range interactions culminating in telomere fusions with centromere alpha-satellite repeats, as well as expansions in HSAT2 and HSAT3 satellite and contractions in ribosomal DNA repeats, were detected in POLQ - / - cells. In conjunction with the expanded telomere lengths of POLQ - /- cells, these results indicate a hitherto unrealized capacity of POLQ for regulation of repeat arrays within the genome. Our findings uncover novel considerations for the efficacy of POLQ inhibitors in clinical cancer interventions, where potential genome destabilizing consequences could drive clonal evolution and resistant disease.
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Affiliation(s)
- Kate Liddiard
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
| | - Alys N Aston-Evans
- Dementia Research Institute, School of Medicine, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff CF24 4HQ, UK
| | - Kez Cleal
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
| | - Eric A Hendrickson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Duncan M Baird
- Division of Cancer and Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
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30
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Petermann E, Lan L, Zou L. Sources, resolution and physiological relevance of R-loops and RNA-DNA hybrids. Nat Rev Mol Cell Biol 2022; 23:521-540. [PMID: 35459910 DOI: 10.1038/s41580-022-00474-x] [Citation(s) in RCA: 102] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2022] [Indexed: 12/12/2022]
Abstract
RNA-DNA hybrids are generated during transcription, DNA replication and DNA repair and are crucial intermediates in these processes. When RNA-DNA hybrids are stably formed in double-stranded DNA, they displace one of the DNA strands and give rise to a three-stranded structure called an R-loop. R-loops are widespread in the genome and are enriched at active genes. R-loops have important roles in regulating gene expression and chromatin structure, but they also pose a threat to genomic stability, especially during DNA replication. To keep the genome stable, cells have evolved a slew of mechanisms to prevent aberrant R-loop accumulation. Although R-loops can cause DNA damage, they are also induced by DNA damage and act as key intermediates in DNA repair such as in transcription-coupled repair and RNA-templated DNA break repair. When the regulation of R-loops goes awry, pathological R-loops accumulate, which contributes to diseases such as neurodegeneration and cancer. In this Review, we discuss the current understanding of the sources of R-loops and RNA-DNA hybrids, mechanisms that suppress and resolve these structures, the impact of these structures on DNA repair and genome stability, and opportunities to therapeutically target pathological R-loops.
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Affiliation(s)
- Eva Petermann
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK
| | - Li Lan
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA, USA
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA, USA.
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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31
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Xu X, Zhang Y, Ha P, Chen Y, Li C, Yen E, Bai Y, Chen R, Wu BM, Da Lio A, Ting K, Soo C, Zheng Z. A novel injectable fibromodulin-releasing granular hydrogel for tendon healing and functional recovery. Bioeng Transl Med 2022; 8:e10355. [PMID: 36684085 PMCID: PMC9842059 DOI: 10.1002/btm2.10355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 05/06/2022] [Accepted: 05/07/2022] [Indexed: 01/25/2023] Open
Abstract
A crucial component of the musculoskeletal system, the tendon is one of the most commonly injured tissues in the body. In severe cases, the ruptured tendon leads to permanent dysfunction. Although many efforts have been devoted to seeking a safe and efficient treatment for enhancing tendon healing, currently existing treatments have not yet achieved a major clinical improvement. Here, an injectable granular hyaluronic acid (gHA)-hydrogel is engineered to deliver fibromodulin (FMOD)-a bioactive extracellular matrix (ECM) that enhances tenocyte mobility and optimizes the surrounding ECM assembly for tendon healing. The FMOD-releasing granular HA (FMOD/gHA)-hydrogel exhibits unique characteristics that are desired for both patients and health providers, such as permitting a microinvasive application and displaying a burst-to-sustained two-phase release of FMOD, which leads to a prompt FMOD delivery followed by a constant dose-maintaining period. Importantly, the generated FMOD-releasing granular HA hydrogel significantly augmented tendon-healing in a fully-ruptured rat's Achilles tendon model histologically, mechanically, and functionally. Particularly, the breaking strength of the wounded tendon and the gait performance of treated rats returns to the same normal level as the healthy controls. In summary, a novel effective FMOD/gHA-hydrogel is developed in response to the urgent demand for promoting tendon healing.
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Affiliation(s)
- Xue Xu
- Department of Oral and Maxillofacial Plastic and Traumatic SurgeryBeijing Stomatological Hospital of Capital Medical UniversityBeijingChina,Division of Plastic and Reconstructive SurgeryDavid Geffen School of Medicine, University of CaliforniaLos AngelesCaliforniaUSA,Division of Growth and DevelopmentSchool of Dentistry, University of CaliforniaLos AngelesCaliforniaUSA
| | - Yulong Zhang
- School of DentistryUniversity of CaliforniaLos AngelesCaliforniaUSA
| | - Pin Ha
- Division of Plastic and Reconstructive SurgeryDavid Geffen School of Medicine, University of CaliforniaLos AngelesCaliforniaUSA,Division of Growth and DevelopmentSchool of Dentistry, University of CaliforniaLos AngelesCaliforniaUSA
| | - Yao Chen
- School of DentistryUniversity of CaliforniaLos AngelesCaliforniaUSA
| | - Chenshuang Li
- Department of OrthodonticsSchool of Dental Medicine, University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Emily Yen
- Arcadia High SchoolArcadiaCaliforniaUSA
| | - Yuxing Bai
- Department of OrthodonticsBeijing Stomatological Hospital of Capital Medical UniversityBeijingChina
| | - Renji Chen
- Department of Oral and Maxillofacial Plastic and Traumatic SurgeryBeijing Stomatological Hospital of Capital Medical UniversityBeijingChina
| | - Benjamin M. Wu
- School of DentistryUniversity of CaliforniaLos AngelesCaliforniaUSA
| | - Andrew Da Lio
- Division of Plastic and Reconstructive SurgeryDavid Geffen School of Medicine, University of CaliforniaLos AngelesCaliforniaUSA
| | - Kang Ting
- Forsyth Research InstituteHarvard UniversityCambridgeMassachusettsUSA,Samueli School of EngineeringUniversity of CaliforniaLos AngelesCaliforniaUSA
| | - Chia Soo
- Division of Plastic and Reconstructive Surgery, Department of Orthopaedic SurgeryThe Orthopaedic Hospital Research Center, University of CaliforniaLos AngelesCaliforniaUSA
| | - Zhong Zheng
- Division of Plastic and Reconstructive SurgeryDavid Geffen School of Medicine, University of CaliforniaLos AngelesCaliforniaUSA,Division of Growth and DevelopmentSchool of Dentistry, University of CaliforniaLos AngelesCaliforniaUSA
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32
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Porubsky D, Höps W, Ashraf H, Hsieh P, Rodriguez-Martin B, Yilmaz F, Ebler J, Hallast P, Maria Maggiolini FA, Harvey WT, Henning B, Audano PA, Gordon DS, Ebert P, Hasenfeld P, Benito E, Zhu Q, Lee C, Antonacci F, Steinrücken M, Beck CR, Sanders AD, Marschall T, Eichler EE, Korbel JO. Recurrent inversion polymorphisms in humans associate with genetic instability and genomic disorders. Cell 2022; 185:1986-2005.e26. [PMID: 35525246 PMCID: PMC9563103 DOI: 10.1016/j.cell.2022.04.017] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/14/2022] [Accepted: 04/08/2022] [Indexed: 12/13/2022]
Abstract
Unlike copy number variants (CNVs), inversions remain an underexplored genetic variation class. By integrating multiple genomic technologies, we discover 729 inversions in 41 human genomes. Approximately 85% of inversions <2 kbp form by twin-priming during L1 retrotransposition; 80% of the larger inversions are balanced and affect twice as many nucleotides as CNVs. Balanced inversions show an excess of common variants, and 72% are flanked by segmental duplications (SDs) or retrotransposons. Since flanking repeats promote non-allelic homologous recombination, we developed complementary approaches to identify recurrent inversion formation. We describe 40 recurrent inversions encompassing 0.6% of the genome, showing inversion rates up to 2.7 × 10-4 per locus per generation. Recurrent inversions exhibit a sex-chromosomal bias and co-localize with genomic disorder critical regions. We propose that inversion recurrence results in an elevated number of heterozygous carriers and structural SD diversity, which increases mutability in the population and predisposes specific haplotypes to disease-causing CNVs.
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Brickner JR, Garzon JL, Cimprich KA. Walking a tightrope: The complex balancing act of R-loops in genome stability. Mol Cell 2022; 82:2267-2297. [PMID: 35508167 DOI: 10.1016/j.molcel.2022.04.014] [Citation(s) in RCA: 78] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/28/2022] [Accepted: 04/10/2022] [Indexed: 12/14/2022]
Abstract
Although transcription is an essential cellular process, it is paradoxically also a well-recognized cause of genomic instability. R-loops, non-B DNA structures formed when nascent RNA hybridizes to DNA to displace the non-template strand as single-stranded DNA (ssDNA), are partially responsible for this instability. Yet, recent work has begun to elucidate regulatory roles for R-loops in maintaining the genome. In this review, we discuss the cellular contexts in which R-loops contribute to genomic instability, particularly during DNA replication and double-strand break (DSB) repair. We also summarize the evidence that R-loops participate as an intermediate during repair and may influence pathway choice to preserve genomic integrity. Finally, we discuss the immunogenic potential of R-loops and highlight their links to disease should they become pathogenic.
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Affiliation(s)
- Joshua R Brickner
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jada L Garzon
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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34
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Ali A, Xiao W, Babar ME, Bi Y. Double-Stranded Break Repair in Mammalian Cells and Precise Genome Editing. Genes (Basel) 2022; 13:genes13050737. [PMID: 35627122 PMCID: PMC9142082 DOI: 10.3390/genes13050737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 12/16/2022] Open
Abstract
In mammalian cells, double-strand breaks (DSBs) are repaired predominantly by error-prone non-homologous end joining (NHEJ), but less prevalently by error-free template-dependent homologous recombination (HR). DSB repair pathway selection is the bedrock for genome editing. NHEJ results in random mutations when repairing DSB, while HR induces high-fidelity sequence-specific variations, but with an undesirable low efficiency. In this review, we first discuss the latest insights into the action mode of NHEJ and HR in a panoramic view. We then propose the future direction of genome editing by virtue of these advancements. We suggest that by switching NHEJ to HR, full fidelity genome editing and robust gene knock-in could be enabled. We also envision that RNA molecules could be repurposed by RNA-templated DSB repair to mediate precise genetic editing.
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Affiliation(s)
- Akhtar Ali
- Key Laboratory of Animal Embryo and Molecular Breeding of Hubei Province, Institute of Animal Science and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (A.A.); (W.X.)
- Department of Biotechnology, Virtual University of Pakistan, Lahore 54000, Pakistan
| | - Wei Xiao
- Key Laboratory of Animal Embryo and Molecular Breeding of Hubei Province, Institute of Animal Science and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (A.A.); (W.X.)
| | - Masroor Ellahi Babar
- The University of Agriculture Dera Ismail Khan, Dera Ismail Khan 29220, Pakistan;
| | - Yanzhen Bi
- Key Laboratory of Animal Embryo and Molecular Breeding of Hubei Province, Institute of Animal Science and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (A.A.); (W.X.)
- Correspondence: ; Tel.: +86-151-0714-8708
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35
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Shapiro JA. What we have learned about evolutionary genome change in the past 7 decades. Biosystems 2022; 215-216:104669. [DOI: 10.1016/j.biosystems.2022.104669] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/23/2022] [Accepted: 03/23/2022] [Indexed: 12/12/2022]
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36
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Carvajal-Maldonado D, Drogalis Beckham L, Wood RD, Doublié S. When DNA Polymerases Multitask: Functions Beyond Nucleotidyl Transfer. Front Mol Biosci 2022; 8:815845. [PMID: 35071329 PMCID: PMC8782244 DOI: 10.3389/fmolb.2021.815845] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 12/13/2021] [Indexed: 11/13/2022] Open
Abstract
DNA polymerases catalyze nucleotidyl transfer, the central reaction in synthesis of DNA polynucleotide chains. They function not only in DNA replication, but also in diverse aspects of DNA repair and recombination. Some DNA polymerases can perform translesion DNA synthesis, facilitating damage tolerance and leading to mutagenesis. In addition to these functions, many DNA polymerases conduct biochemically distinct reactions. This review presents examples of DNA polymerases that carry out nuclease (3'-5' exonuclease, 5' nuclease, or end-trimming nuclease) or lyase (5' dRP lyase) extracurricular activities. The discussion underscores how DNA polymerases have a remarkable ability to manipulate DNA strands, sometimes involving relatively large intramolecular movement.
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Affiliation(s)
- Denisse Carvajal-Maldonado
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, TX, United States
| | - Lea Drogalis Beckham
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, United States
| | - Richard D Wood
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Center, Houston, TX, United States
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, United States
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37
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Nioi M, Napoli PE. The Waiver of Patent Protections for COVID-19 Vaccines During the Ongoing Pandemic and the Conspiracy Theories: Lights and Shadows of an Issue on the Ground. Front Med (Lausanne) 2021; 8:756623. [PMID: 34805221 PMCID: PMC8599977 DOI: 10.3389/fmed.2021.756623] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 10/15/2021] [Indexed: 11/24/2022] Open
Affiliation(s)
- Matteo Nioi
- Department of Medical Sciences and Public Health, Forensic Medicine Unit, University of Cagliari, Cagliari, Italy
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Rossi MJ, DiDomenico SF, Patel M, Mazin AV. RAD52: Paradigm of Synthetic Lethality and New Developments. Front Genet 2021; 12:780293. [PMID: 34887904 PMCID: PMC8650160 DOI: 10.3389/fgene.2021.780293] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/05/2021] [Indexed: 12/31/2022] Open
Abstract
DNA double-strand breaks and inter-strand cross-links are the most harmful types of DNA damage that cause genomic instability that lead to cancer development. The highest fidelity pathway for repairing damaged double-stranded DNA is termed Homologous recombination (HR). Rad52 is one of the key HR proteins in eukaryotes. Although it is critical for most DNA repair and recombination events in yeast, knockouts of mammalian RAD52 lack any discernable phenotypes. As a consequence, mammalian RAD52 has been long overlooked. That is changing now, as recent work has shown RAD52 to be critical for backup DNA repair pathways in HR-deficient cancer cells. Novel findings have shed light on RAD52's biochemical activities. RAD52 promotes DNA pairing (D-loop formation), single-strand DNA and DNA:RNA annealing, and inverse strand exchange. These activities contribute to its multiple roles in DNA damage repair including HR, single-strand annealing, break-induced replication, and RNA-mediated repair of DNA. The contributions of RAD52 that are essential to the viability of HR-deficient cancer cells are currently under investigation. These new findings make RAD52 an attractive target for the development of anti-cancer therapies against BRCA-deficient cancers.
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39
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Franklin A, Steele EJ. RNA-directed DNA repair and antibody somatic hypermutation. Trends Genet 2021; 38:426-436. [PMID: 34740453 DOI: 10.1016/j.tig.2021.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/03/2021] [Accepted: 10/04/2021] [Indexed: 10/19/2022]
Abstract
Somatic hypermutation at antibody loci affects both deoxyadenosine-deoxythymidine (A/T) and deoxycytidine-deoxyguanosine (C/G) pairs. Deamination of C to deoxyuridine (U) by activation-induced deaminase (AID) explains how mutation at C/G pairs is potentiated. Mutation at A/T pairs is triggered during the initial stages of repair of AID-generated U lesions and occurs through an as yet unknown mechanism in which polymerase η has a major role. Recent evidence confirms that human polymerase η can act as a reverse transcriptase. Here, we compare the popular suggestion of mutation at A/T pairs through nucleotide mispairing (owing to polymerase error) during short-patch repair synthesis with the alternative proposal of mutation at A/T pairs through RNA editing and RNA-directed DNA repair.
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Affiliation(s)
- Andrew Franklin
- Novartis Pharma AG, Novartis Campus, 4056, Basel, Switzerland.
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40
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Tulsiyan K, Jena S, González-Viegas M, Kar RK, Biswal HS. Structural Dynamics of RNA in the Presence of Choline Amino Acid Based Ionic Liquid: A Spectroscopic and Computational Outlook. ACS CENTRAL SCIENCE 2021; 7:1688-1697. [PMID: 34729412 PMCID: PMC8554839 DOI: 10.1021/acscentsci.1c00768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Indexed: 05/03/2023]
Abstract
Ribonucleic acid (RNA) is exceedingly sensitive to degradation compared to DNA. The current protocol for storage of purified RNA requires freezing conditions below -20 °C. Recent advancements in biological chemistry have identified amino acid-based ionic liquids as suitable preservation media for RNA, even in the presence of degrading enzymes. However, the mechanistic insight into the interaction between ILs and RNA is unclear. To the best of our knowledge, no attempts are made so far to provide a molecular view. This work aims to establish a detailed understanding of how ILs enable structural stability to RNA sourced from Torula yeast. Herein, we manifest the hypothesis of multimodal binding of IL and its minimal perturbation to the macromolecular structure, with several spectroscopic techniques such as time-resolved fluorescence and fluorescence correlation spectroscopy (FCS) aided with molecular dynamics at microsecond time scales. Relevant structural and thermodynamic details from biophysical experiments confirm that even long-term RNA preservation with ILs is a possible alternative devoid of any structural deformation. These results establish a unifying mechanism of how ILs are maintaining conformational integrity and thermal stability. The atomistic insights are transferable for their potential applications in drug delivery and biomaterials by considering the advantages of having maximum structural retention and minimum toxicity.
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Affiliation(s)
- Kiran
Devi Tulsiyan
- School
of Chemical Sciences, National Institute
of Science Education and Research (NISER), Bhimpur-Padanpur, Via-Jatni, District, Khurda, 752050, Bhubaneswar, India
- Homi
Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Subhrakant Jena
- School
of Chemical Sciences, National Institute
of Science Education and Research (NISER), Bhimpur-Padanpur, Via-Jatni, District, Khurda, 752050, Bhubaneswar, India
- Homi
Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - María González-Viegas
- Institut
für Biologie, Humboldt Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
| | - Rajiv K. Kar
- Faculty
II-Mathematics and Natural Sciences, Technische
Universität Berlin, Sekr. PC 14, Strasse des 17, Juni 135, D-10623 Berlin, Germany
| | - Himansu S. Biswal
- School
of Chemical Sciences, National Institute
of Science Education and Research (NISER), Bhimpur-Padanpur, Via-Jatni, District, Khurda, 752050, Bhubaneswar, India
- Homi
Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
- . Phone: +91-674-2494 185/186
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41
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Salas-Leiva DE, Tromer EC, Curtis BA, Jerlström-Hultqvist J, Kolisko M, Yi Z, Salas-Leiva JS, Gallot-Lavallée L, Williams SK, Kops GJPL, Archibald JM, Simpson AGB, Roger AJ. Genomic analysis finds no evidence of canonical eukaryotic DNA processing complexes in a free-living protist. Nat Commun 2021; 12:6003. [PMID: 34650064 PMCID: PMC8516963 DOI: 10.1038/s41467-021-26077-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 09/14/2021] [Indexed: 12/14/2022] Open
Abstract
Cells replicate and segregate their DNA with precision. Previous studies showed that these regulated cell-cycle processes were present in the last eukaryotic common ancestor and that their core molecular parts are conserved across eukaryotes. However, some metamonad parasites have secondarily lost components of the DNA processing and segregation apparatuses. To clarify the evolutionary history of these systems in these unusual eukaryotes, we generated a genome assembly for the free-living metamonad Carpediemonas membranifera and carried out a comparative genomics analysis. Here, we show that parasitic and free-living metamonads harbor an incomplete set of proteins for processing and segregating DNA. Unexpectedly, Carpediemonas species are further streamlined, lacking the origin recognition complex, Cdc6 and most structural kinetochore subunits. Carpediemonas species are thus the first known eukaryotes that appear to lack this suite of conserved complexes, suggesting that they likely rely on yet-to-be-discovered or alternative mechanisms to carry out these fundamental processes.
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Affiliation(s)
- Dayana E. Salas-Leiva
- grid.55602.340000 0004 1936 8200Institute for Comparative Genomics (ICG), Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2 Canada ,grid.5335.00000000121885934Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Eelco C. Tromer
- grid.5335.00000000121885934Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom ,grid.4830.f0000 0004 0407 1981Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Bruce A. Curtis
- grid.55602.340000 0004 1936 8200Institute for Comparative Genomics (ICG), Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2 Canada
| | - Jon Jerlström-Hultqvist
- grid.55602.340000 0004 1936 8200Institute for Comparative Genomics (ICG), Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2 Canada
| | - Martin Kolisko
- grid.418095.10000 0001 1015 3316Institute of Parasitology, Biology Centre, Czech Acad. Sci, České Budějovice, Czech Republic
| | - Zhenzhen Yi
- grid.263785.d0000 0004 0368 7397Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, School of Life Science, South China Normal University, Guangzhou, 510631 China
| | - Joan S. Salas-Leiva
- grid.466575.30000 0001 1835 194XCONACyT-Centro de Investigación en Materiales Avanzados, Departamento de medio ambiente y energía, Miguel de Cervantes 120, Complejo Industrial Chihuahua, 31136 Chihuahua, Chih. México
| | - Lucie Gallot-Lavallée
- grid.55602.340000 0004 1936 8200Institute for Comparative Genomics (ICG), Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2 Canada
| | - Shelby K. Williams
- grid.55602.340000 0004 1936 8200Institute for Comparative Genomics (ICG), Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2 Canada
| | - Geert J. P. L. Kops
- grid.7692.a0000000090126352Oncode Institute, Hubrecht Institute – KNAW (Royal Netherlands Academy of Arts and Sciences) and University Medical Centre Utrecht, Utrecht, The Netherlands
| | - John M. Archibald
- grid.55602.340000 0004 1936 8200Institute for Comparative Genomics (ICG), Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2 Canada
| | - Alastair G. B. Simpson
- grid.55602.340000 0004 1936 8200Institute for Comparative Genomics (ICG), Department of Biology, Dalhousie University, Halifax, NS B3H 4R2 Canada
| | - Andrew J. Roger
- grid.55602.340000 0004 1936 8200Institute for Comparative Genomics (ICG), Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2 Canada
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Frock RL, Sadeghi C, Meng J, Wang JL. DNA End Joining: G0-ing to the Core. Biomolecules 2021; 11:biom11101487. [PMID: 34680120 PMCID: PMC8533500 DOI: 10.3390/biom11101487] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 12/28/2022] Open
Abstract
Humans have evolved a series of DNA double-strand break (DSB) repair pathways to efficiently and accurately rejoin nascently formed pairs of double-stranded DNA ends (DSEs). In G0/G1-phase cells, non-homologous end joining (NHEJ) and alternative end joining (A-EJ) operate to support covalent rejoining of DSEs. While NHEJ is predominantly utilized and collaborates extensively with the DNA damage response (DDR) to support pairing of DSEs, much less is known about A-EJ collaboration with DDR factors when NHEJ is absent. Non-cycling lymphocyte progenitor cells use NHEJ to complete V(D)J recombination of antigen receptor genes, initiated by the RAG1/2 endonuclease which holds its pair of targeted DSBs in a synapse until each specified pair of DSEs is handed off to the NHEJ DSB sensor complex, Ku. Similar to designer endonuclease DSBs, the absence of Ku allows for A-EJ to access RAG1/2 DSEs but with random pairing to complete their repair. Here, we describe recent insights into the major phases of DSB end joining, with an emphasis on synapsis and tethering mechanisms, and bring together new and old concepts of NHEJ vs. A-EJ and on RAG2-mediated repair pathway choice.
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Carbonara K, Andonovski M, Coorssen JR. Proteomes Are of Proteoforms: Embracing the Complexity. Proteomes 2021; 9:38. [PMID: 34564541 PMCID: PMC8482110 DOI: 10.3390/proteomes9030038] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 08/24/2021] [Accepted: 08/29/2021] [Indexed: 12/17/2022] Open
Abstract
Proteomes are complex-much more so than genomes or transcriptomes. Thus, simplifying their analysis does not simplify the issue. Proteomes are of proteoforms, not canonical proteins. While having a catalogue of amino acid sequences provides invaluable information, this is the Proteome-lite. To dissect biological mechanisms and identify critical biomarkers/drug targets, we must assess the myriad of proteoforms that arise at any point before, after, and between translation and transcription (e.g., isoforms, splice variants, and post-translational modifications [PTM]), as well as newly defined species. There are numerous analytical methods currently used to address proteome depth and here we critically evaluate these in terms of the current 'state-of-the-field'. We thus discuss both pros and cons of available approaches and where improvements or refinements are needed to quantitatively characterize proteomes. To enable a next-generation approach, we suggest that advances lie in transdisciplinarity via integration of current proteomic methods to yield a unified discipline that capitalizes on the strongest qualities of each. Such a necessary (if not revolutionary) shift cannot be accomplished by a continued primary focus on proteo-genomics/-transcriptomics. We must embrace the complexity. Yes, these are the hard questions, and this will not be easy…but where is the fun in easy?
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Affiliation(s)
| | | | - Jens R. Coorssen
- Faculties of Applied Health Sciences and Mathematics & Science, Departments of Health Sciences and Biological Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (K.C.); (M.A.)
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44
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Zahn KE, Jensen RB. Polymerase θ Coordinates Multiple Intrinsic Enzymatic Activities during DNA Repair. Genes (Basel) 2021; 12:1310. [PMID: 34573292 PMCID: PMC8470613 DOI: 10.3390/genes12091310] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 11/16/2022] Open
Abstract
The POLQ gene encodes DNA polymerase θ, a 2590 amino acid protein product harboring DNA-dependent ATPase, template-dependent DNA polymerase, dNTP-dependent endonuclease, and 5'-dRP lyase functions. Polymerase θ participates at an essential step of a DNA double-strand break repair pathway able to join 5'-resected substrates by locating and pairing microhomologies present in 3'-overhanging single-stranded tails, cleaving the extraneous 3'-DNA by dNTP-dependent end-processing, before extending the nascent 3' end from the microhomology annealing site. Metazoans require polymerase θ for full resistance to DNA double-strand break inducing agents but can survive knockout of the POLQ gene. Cancer cells with compromised homologous recombination, or other DNA repair defects, over-utilize end-joining by polymerase θ and often over-express the POLQ gene. This dependency points to polymerase θ as an ideal drug target candidate and multiple drug-development programs are now preparing to enter clinical trials with small-molecule inhibitors. Specific inhibitors of polymerase θ would not only be predicted to treat BRCA-mutant cancers, but could thwart accumulated resistance to current standard-of-care cancer therapies and overcome PARP-inhibitor resistance in patients. This article will discuss synthetic lethal strategies targeting polymerase θ in DNA damage-response-deficient cancers and summarize data, describing molecular structures and enzymatic functions.
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Affiliation(s)
- Karl E. Zahn
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Repare Therapeutics, 7210 Rue Frederick Banting, Montreal, QC H4S 2A1, Canada
| | - Ryan B. Jensen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
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45
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Herbert A. The Simple Biology of Flipons and Condensates Enhances the Evolution of Complexity. Molecules 2021; 26:molecules26164881. [PMID: 34443469 PMCID: PMC8400190 DOI: 10.3390/molecules26164881] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/10/2021] [Accepted: 08/10/2021] [Indexed: 01/09/2023] Open
Abstract
The classical genetic code maps nucleotide triplets to amino acids. The associated sequence composition is complex, representing many elaborations during evolution of form and function. Other genomic elements code for the expression and processing of RNA transcripts. However, over 50% of the human genome consists of widely dispersed repetitive sequences. Among these are simple sequence repeats (SSRs), representing a class of flipons, that under physiological conditions, form alternative nucleic acid conformations such as Z-DNA, G4 quartets, I-motifs, and triplexes. Proteins that bind in a structure-specific manner enable the seeding of condensates with the potential to regulate a wide range of biological processes. SSRs also encode the low complexity peptide repeats to patch condensates together, increasing the number of combinations possible. In situations where SSRs are transcribed, SSR-specific, single-stranded binding proteins may further impact condensate formation. Jointly, flipons and patches speed evolution by enhancing the functionality of condensates. Here, the focus is on the selection of SSR flipons and peptide patches that solve for survival under a wide range of environmental contexts, generating complexity with simple parts.
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Affiliation(s)
- Alan Herbert
- Unit 3412, Discovery, InsideOutBio 42 8th Street, Charlestown, MA 02129, USA
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46
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Chen XS, Pomerantz RT. DNA Polymerase θ: A Cancer Drug Target with Reverse Transcriptase Activity. Genes (Basel) 2021; 12:1146. [PMID: 34440316 PMCID: PMC8391894 DOI: 10.3390/genes12081146] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/16/2021] [Accepted: 07/20/2021] [Indexed: 12/11/2022] Open
Abstract
The emergence of precision medicine from the development of Poly (ADP-ribose) polymerase (PARP) inhibitors that preferentially kill cells defective in homologous recombination has sparked wide interest in identifying and characterizing additional DNA repair enzymes that are synthetic lethal with HR factors. DNA polymerase theta (Polθ) is a validated anti-cancer drug target that is synthetic lethal with HR factors and other DNA repair proteins and confers cellular resistance to various genotoxic cancer therapies. Since its initial characterization as a helicase-polymerase fusion protein in 2003, many exciting and unexpected activities of Polθ in microhomology-mediated end-joining (MMEJ) and translesion synthesis (TLS) have been discovered. Here, we provide a short review of Polθ's DNA repair activities and its potential as a drug target and highlight a recent report that reveals Polθ as a naturally occurring reverse transcriptase (RT) in mammalian cells.
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Affiliation(s)
- Xiaojiang S. Chen
- Molecular and Computational Biology, USC Dornsife Department of Biological Sciences, 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
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