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Khristich AN, Mirkin SM. On the wrong DNA track: Molecular mechanisms of repeat-mediated genome instability. J Biol Chem 2020; 295:4134-4170. [PMID: 32060097 PMCID: PMC7105313 DOI: 10.1074/jbc.rev119.007678] [Citation(s) in RCA: 160] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Expansions of simple tandem repeats are responsible for almost 50 human diseases, the majority of which are severe, degenerative, and not currently treatable or preventable. In this review, we first describe the molecular mechanisms of repeat-induced toxicity, which is the connecting link between repeat expansions and pathology. We then survey alternative DNA structures that are formed by expandable repeats and review the evidence that formation of these structures is at the core of repeat instability. Next, we describe the consequences of the presence of long structure-forming repeats at the molecular level: somatic and intergenerational instability, fragility, and repeat-induced mutagenesis. We discuss the reasons for gender bias in intergenerational repeat instability and the tissue specificity of somatic repeat instability. We also review the known pathways in which DNA replication, transcription, DNA repair, and chromatin state interact and thereby promote repeat instability. We then discuss possible reasons for the persistence of disease-causing DNA repeats in the genome. We describe evidence suggesting that these repeats are a payoff for the advantages of having abundant simple-sequence repeats for eukaryotic genome function and evolvability. Finally, we discuss two unresolved fundamental questions: (i) why does repeat behavior differ between model systems and human pedigrees, and (ii) can we use current knowledge on repeat instability mechanisms to cure repeat expansion diseases?
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Affiliation(s)
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, Massachusetts 02155.
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2
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Liu X, Feng D, Huo X, Xiao X, Chen Z. Association of intron microsatellite status and exon mutational profiles of TP53 in human colorectal cancer. Exp Ther Med 2019; 18:4287-4294. [PMID: 31777536 PMCID: PMC6862561 DOI: 10.3892/etm.2019.8095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 09/10/2019] [Indexed: 01/10/2023] Open
Abstract
Microsatellite instability (MSI) and loss of heterozygosity (LOH), which cause genomic instability, contribute to cancer pathogenesis. However, only few studies have evaluated the association of a single microsatellite locus of the TP53 gene with the mutation spectra of TP53 exons. A total of 256 patients with colorectal cancer were enrolled in the present study. MSI/LOH alterations of a microsatellite in the TP53 intron (TP53ALU) were assessed via short tandem repeat scanning. The exon mutation profile was evaluated by direct sequencing. The mutation rate of TP53 exons was significantly higher in tumors with LOH alterations of TP53 introns compared with those in tumors with a microsatellite-stable status in the TP53 intron (P=0.0047). TNM stage II was significantly more frequent in MSI vs. LOH or MSS of the TP53 intron (P=0.027 and P=0.048, respectively). Thus, microsatellite alterations may be valuable predictors of TP53 exon mutation and the TNM stage of colorectal cancers.
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Affiliation(s)
- Xin Liu
- Department of Medical Genetics, School of Basic Medical Sciences, Capital Medical University, Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Beijing 100069, P.R. China
| | - Dandan Feng
- Department of Medical Genetics, School of Basic Medical Sciences, Capital Medical University, Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Beijing 100069, P.R. China
| | - Xueyun Huo
- Department of Medical Genetics, School of Basic Medical Sciences, Capital Medical University, Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Beijing 100069, P.R. China
| | - Xiaoqin Xiao
- Department of Medical Genetics, School of Basic Medical Sciences, Capital Medical University, Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Beijing 100069, P.R. China
| | - Zhenwen Chen
- Department of Medical Genetics, School of Basic Medical Sciences, Capital Medical University, Beijing Key Laboratory of Cancer Invasion and Metastasis Research, Beijing 100069, P.R. China
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3
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DeVito S, Woodrick J, Song L, Roy R. Mutagenic potential of hypoxanthine in live human cells. Mutat Res 2017; 803-805:9-16. [PMID: 28704682 DOI: 10.1016/j.mrfmmm.2017.06.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Revised: 06/06/2017] [Accepted: 06/20/2017] [Indexed: 01/08/2023]
Abstract
Hypoxanthine (Hx) is a major DNA lesion generated by deamination of adenine during chronic inflammatory conditions, which is an underlying cause of various diseases including cancer of colon, liver, pancreas, bladder and stomach. There is evidence that deamination of DNA bases induces mutations, but no study has directly linked Hx accumulation to mutagenesis and strand-specific mutations yet in human cells. Using a site-specific mutagenesis approach, we report the first direct evidence of mutation potential and pattern of Hx in live human cells. We investigated Hx-induced mutations in human nonmalignant HEK293 and cancer HCT116 cell lines and found that Hx is mutagenic in both HEK293 and HCT116 cell lines. There is a strand bias for Hx-mediated mutations in both the cell lines; the Hx in lagging strand is more mutagenic than in leading strand. There is also some difference in cell types regarding the strand bias for mutation types; HEK293 cells showed largely deletion (>80%) mutations in both leading and lagging strand and the rest were insertions and A:T→G:C transition mutations in leading and lagging strands, respectively, whereas in HCT116 cells we observed 60% A:T→G:C transition mutations in the leading strand and 100% deletions in the lagging strand. Overall, Hx is a highly mutagenic lesion capable of generating A:T→G:C transitions and large deletions with a significant variation in leading and lagging strands in human cells. In recent meta-analysis study A→G (T→C) mutations were found to be a prominent signature in a variety of cancers, including a majority types that are induced by inflammation. The deletions are known to be a major cause of copy-number variations or CNVs, which is a major underlying cause of many human diseases including mental illness, developmental disorders and cancer. Thus, Hx, a major DNA lesion induced by different deamination mechanisms, has potential to initiate inflammation-driven carcinogenesis in addition to various human pathophysiological consequences.
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Affiliation(s)
- Stephen DeVito
- Department of Oncology, Georgetown Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, United States
| | - Jordan Woodrick
- Department of Oncology, Georgetown Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, United States
| | - Linze Song
- Department of Oncology, Georgetown Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, United States
| | - Rabindra Roy
- Department of Oncology, Georgetown Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, United States.
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Pai CC, Kearsey SE. A Critical Balance: dNTPs and the Maintenance of Genome Stability. Genes (Basel) 2017; 8:genes8020057. [PMID: 28146119 PMCID: PMC5333046 DOI: 10.3390/genes8020057] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 01/24/2017] [Indexed: 01/14/2023] Open
Abstract
A crucial factor in maintaining genome stability is establishing deoxynucleoside triphosphate (dNTP) levels within a range that is optimal for chromosomal replication. Since DNA replication is relevant to a wide range of other chromosomal activities, these may all be directly or indirectly affected when dNTP concentrations deviate from a physiologically normal range. The importance of understanding these consequences is relevant to genetic disorders that disturb dNTP levels, and strategies that inhibit dNTP synthesis in cancer chemotherapy and for treatment of other disorders. We review here how abnormal dNTP levels affect DNA replication and discuss the consequences for genome stability.
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Affiliation(s)
- Chen-Chun Pai
- CRUK-MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK.
| | - Stephen E Kearsey
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
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Potentiation of hydrogen peroxide toxicity: From catalase inhibition to stable DNA-iron complexes. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2016; 773:274-281. [PMID: 28927535 DOI: 10.1016/j.mrrev.2016.08.006] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 08/29/2016] [Indexed: 12/15/2022]
Abstract
Hydrogen peroxide (H2O2) is unique among general toxins, because it is stable in abiotic environments at ambient temperature and neutral pH, yet rapidly kills any type of cells by producing highly-reactive hydroxyl radicals. This life-specific reactivity follows the distribution of soluble iron, Fe(II) (which combines with H2O2 to form the famous Fenton's reagent),Fe(II) is concentrated inside cells, but is virtually absent outside them. Because of the immediate danger of H2O2, all cells have powerful H2O2 scavengers, the equally famous catalases, which enable cells to survive thousand-fold higher concentrations of H2O2 and, in combination with adequate movement of H2O2 across membranes, make the killing H2O2 concentrations virtually impractical to generate in vivo. And yet, low concentrations of H2O2 are somehow used as an efficient biological weapon. Here we review several examples of how cells potentiate H2O2 toxicity with other chemicals. At first, these potentiators were thought to simply inhibit catalases, but recent findings with cyanide suggest that potentiators mostly promote the other side of Fenton's reaction, recruiting iron from cell depots into stable DNA-iron complexes that, in the presence of elevated H2O2, efficiently break duplex DNA, pulverizing the chromosome. This multifaceted potentiation of H2O2 toxicity results in robust and efficient killing.
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Barthelemy J, Hanenberg H, Leffak M. FANCJ is essential to maintain microsatellite structure genome-wide during replication stress. Nucleic Acids Res 2016; 44:6803-16. [PMID: 27179029 PMCID: PMC5001596 DOI: 10.1093/nar/gkw433] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Accepted: 05/06/2016] [Indexed: 12/15/2022] Open
Abstract
Microsatellite DNAs that form non-B structures are implicated in replication fork stalling, DNA double strand breaks (DSBs) and human disease. Fanconi anemia (FA) is an inherited disorder in which mutations in at least nineteen genes are responsible for the phenotypes of genome instability and cancer predisposition. FA pathway proteins are active in the resolution of non-B DNA structures including interstrand crosslinks, G quadruplexes and DNA triplexes. In FANCJ helicase depleted cells, we show that hydroxyurea or aphidicolin treatment leads to loss of microsatellite polymerase chain reaction signals and to chromosome recombination at an ectopic hairpin forming CTG/CAG repeat in the HeLa genome. Moreover, diverse endogenous microsatellite signals were also lost upon replication stress after FANCJ depletion, and in FANCJ null patient cells. The phenotype of microsatellite signal instability is specific for FANCJ apart from the intact FA pathway, and is consistent with DSBs at microsatellites genome-wide in FANCJ depleted cells following replication stress.
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Affiliation(s)
- Joanna Barthelemy
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Helmut Hanenberg
- Department of Pediatrics III, University Children's Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany Department of Otorhinolaryngology & Head/Neck Surgery, Heinrich Heine University, 40225 Duesseldorf, Germany
| | - Michael Leffak
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
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Drosopoulos WC, Kosiyatrakul ST, Schildkraut CL. BLM helicase facilitates telomere replication during leading strand synthesis of telomeres. J Cell Biol 2016. [PMID: 26195664 PMCID: PMC4508891 DOI: 10.1083/jcb.201410061] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BLM helicase facilitates telomere replication by resolving G-quadruplex structures that can form in the G-rich repeats during leading strand synthesis. Based on its in vitro unwinding activity on G-quadruplex (G4) DNA, the Bloom syndrome–associated helicase BLM is proposed to participate in telomere replication by aiding fork progression through G-rich telomeric DNA. Single molecule analysis of replicated DNA (SMARD) was used to determine the contribution of BLM helicase to telomere replication. In BLM-deficient cells, replication forks initiating from origins within the telomere, which copy the G-rich strand by leading strand synthesis, moved slower through the telomere compared with the adjacent subtelomere. Fork progression through the telomere was further slowed in the presence of a G4 stabilizer. Using a G4-specific antibody, we found that deficiency of BLM, or another G4-unwinding helicase, the Werner syndrome-associated helicase WRN, resulted in increased G4 structures in cells. Importantly, deficiency of either helicase led to greater increases in G4 DNA detected in the telomere compared with G4 seen genome-wide. Collectively, our findings are consistent with BLM helicase facilitating telomere replication by resolving G4 structures formed during copying of the G-rich strand by leading strand synthesis.
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Affiliation(s)
| | | | - Carl L Schildkraut
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY 10461
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Li Y, Lu Y, Polak U, Lin K, Shen J, Farmer J, Seyer L, Bhalla AD, Rozwadowska N, Lynch DR, Butler JS, Napierala M. Expanded GAA repeats impede transcription elongation through the FXN gene and induce transcriptional silencing that is restricted to the FXN locus. Hum Mol Genet 2015; 24:6932-43. [PMID: 26401053 PMCID: PMC4654050 DOI: 10.1093/hmg/ddv397] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 09/21/2015] [Indexed: 11/13/2022] Open
Abstract
Friedreich's ataxia (FRDA) is a severe neurodegenerative disease caused by homozygous expansion of the guanine-adenine-adenine (GAA) repeats in intron 1 of the FXN gene leading to transcriptional repression of frataxin expression. Post-translational histone modifications that typify heterochromatin are enriched in the vicinity of the repeats, whereas active chromatin marks in this region are underrepresented in FRDA samples. Yet, the immediate effect of the expanded repeats on transcription progression through FXN and their long-range effect on the surrounding genomic context are two critical questions that remain unanswered in the molecular pathogenesis of FRDA. To address these questions, we conducted next-generation RNA sequencing of a large cohort of FRDA and control primary fibroblasts. This comprehensive analysis revealed that the GAA-induced silencing effect does not influence expression of neighboring genes upstream or downstream of FXN. Furthermore, no long-range silencing effects were detected across a large portion of chromosome 9. Additionally, results of chromatin immunoprecipitation studies confirmed that histone modifications associated with repressed transcription are confined to the FXN locus. Finally, deep sequencing of FXN pre-mRNA molecules revealed a pronounced defect in the transcription elongation rate in FRDA cells when compared with controls. These results indicate that approaches aimed to reactivate frataxin expression should simultaneously address deficits in transcription initiation and elongation at the FXN locus.
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Affiliation(s)
- Yanjie Li
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA
| | - Yue Lu
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, USA
| | - Urszula Polak
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, USA, Department of Cell Biology, Poznan University of Medical Sciences, Rokietnicka 5D, Poznan 60-806, Poland
| | - Kevin Lin
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, USA
| | - Jianjun Shen
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, USA
| | - Jennifer Farmer
- Division of Neurology and Pediatrics, Children's Hospital of Philadelphia, Abramson Research Center Room 502, Philadelphia, PA 19104, USA
| | - Lauren Seyer
- Division of Neurology and Pediatrics, Children's Hospital of Philadelphia, Abramson Research Center Room 502, Philadelphia, PA 19104, USA
| | - Angela D Bhalla
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA
| | - Natalia Rozwadowska
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA, Institute of Human Genetics, Polish Academy of Science, Strzeszynska 32, Poznan 60-479, Poland
| | - David R Lynch
- Division of Neurology and Pediatrics, Children's Hospital of Philadelphia, Abramson Research Center Room 502, Philadelphia, PA 19104, USA
| | - Jill Sergesketter Butler
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA,
| | - Marek Napierala
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA, Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan 61-704, Poland and
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9
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Jackson A, Okely EA, Leach DRF. Expansion of CAG repeats in Escherichia coli is controlled by single-strand DNA exonucleases of both polarities. Genetics 2014; 198:509-17. [PMID: 25081568 PMCID: PMC4196609 DOI: 10.1534/genetics.114.168245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The expansion of CAG·CTG repeat tracts is responsible for several neurodegenerative diseases, including Huntington disease and myotonic dystrophy. Understanding the molecular mechanism of CAG·CTG repeat tract expansion is therefore important if we are to develop medical interventions limiting expansion rates. Escherichia coli provides a simple and tractable model system to understand the fundamental properties of these DNA sequences, with the potential to suggest pathways that might be conserved in humans or to highlight differences in behavior that could signal the existence of human-specific factors affecting repeat array processing. We have addressed the genetics of CAG·CTG repeat expansion in E. coli and shown that these repeat arrays expand via an orientation-independent mechanism that contrasts with the orientation dependence of CAG·CTG repeat tract contraction. The helicase Rep contributes to the orientation dependence of repeat tract contraction and limits repeat tract expansion in both orientations. However, RuvAB-dependent fork reversal, which occurs in a rep mutant, is not responsible for the observed increase in expansions. The frequency of repeat tract expansion is controlled by both the 5'-3' exonuclease RecJ and the 3'-5' exonuclease ExoI, observations that suggest the importance of both 3'and 5' single-strand ends in the pathway of CAG·CTG repeat tract expansion. We discuss the relevance of our results to two competing models of repeat tract expansion.
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Affiliation(s)
- Adam Jackson
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JR, United Kingdom
| | - Ewa A Okely
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JR, United Kingdom
| | - David R F Leach
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JR, United Kingdom
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10
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Pillaire MJ, Bétous R, Hoffmann JS. Role of DNA polymerase κ in the maintenance of genomic stability. Mol Cell Oncol 2014; 1:e29902. [PMID: 27308312 PMCID: PMC4905163 DOI: 10.4161/mco.29902] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 06/20/2014] [Accepted: 06/23/2014] [Indexed: 12/28/2022]
Abstract
To ensure high cell viability and genomic stability, cells have evolved two major mechanisms to deal with the constant challenge of DNA replication fork arrest during S phase of the cell cycle: (1) induction of the ataxia telangiectasia and Rad3-related (ATR) replication checkpoint mechanism, and (2) activation of a pathway that bypasses DNA damage and DNA with abnormal structure and is mediated by translesion synthesis (TLS) Y-family DNA polymerases. This review focuses on how DNA polymerase kappa (Pol κ), one of the most highly conserved TLS DNA polymerases, is involved in each of these pathways and thereby coordinates them to choreograph the response to a stalled replication fork. We also describe how loss of Pol κ regulation, which occurs frequently in human cancers, affects genomic stability and contributes to cancer development.
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Affiliation(s)
- Marie-Jeanne Pillaire
- Labellisée Ligue contre le Cancer 2013; INSERM Unit 1037; CNRS ERL 5294; Cancer Research Center of Toulouse; CHU Purpan; Toulouse, France; Université Paul Sabatier; University of Toulouse III; Toulouse, France
| | - Rémy Bétous
- Labellisée Ligue contre le Cancer 2013; INSERM Unit 1037; CNRS ERL 5294; Cancer Research Center of Toulouse; CHU Purpan; Toulouse, France; Université Paul Sabatier; University of Toulouse III; Toulouse, France
| | - Jean-Sébastien Hoffmann
- Labellisée Ligue contre le Cancer 2013; INSERM Unit 1037; CNRS ERL 5294; Cancer Research Center of Toulouse; CHU Purpan; Toulouse, France; Université Paul Sabatier; University of Toulouse III; Toulouse, France
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11
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Mathews CK. Deoxyribonucleotides as genetic and metabolic regulators. FASEB J 2014; 28:3832-40. [PMID: 24928192 DOI: 10.1096/fj.14-251249] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 06/02/2014] [Indexed: 01/12/2023]
Abstract
For >35 yr, we have known that the accuracy of DNA replication is controlled in large part by the relative concentrations of the 4 canonical deoxyribonucleoside 5'-triphosphates (dNTPs) at the replisome. Since this field was last reviewed, ∼8 yr ago, there has been increased understanding of the mutagenic pathways as they occur in living cells. At the same time, aspects of deoxyribonucleotide metabolism have been shown to be critically involved in processes as diverse as cell cycle control, protooncogene expression, cellular defense against HIV infection, replication rate control, telomere length control, and mitochondrial function. Evidence supports a relationship between dNTP pools and microsatellite repeat instability. Relationships between dNTP synthesis and breakdown in controlling steady-state pools have become better defined. In addition, new experimental approaches have allowed definitive analysis of mutational pathways induced by dNTP pool abnormalities, both in Escherichia coli and in yeast. Finally, ribonucleoside triphosphate (rNTP) pools have been shown to be critical determinants of DNA replication fidelity. These developments are discussed in this review article.
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Affiliation(s)
- Christopher K Mathews
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
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12
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Guarino E, Salguero I, Kearsey SE. Cellular regulation of ribonucleotide reductase in eukaryotes. Semin Cell Dev Biol 2014; 30:97-103. [PMID: 24704278 DOI: 10.1016/j.semcdb.2014.03.030] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 03/26/2014] [Indexed: 12/22/2022]
Abstract
Synthesis of deoxynucleoside triphosphates (dNTPs) is essential for both DNA replication and repair and a key step in this process is catalyzed by ribonucleotide reductases (RNRs), which reduce ribonucleotides (rNDPs) to their deoxy forms. Tight regulation of RNR is crucial for maintaining the correct levels of all four dNTPs, which is important for minimizing the mutation rate and avoiding genome instability. Although allosteric control of RNR was the first discovered mechanism involved in regulation of the enzyme, other controls have emerged in recent years. These include regulation of expression of RNR genes, proteolysis of RNR subunits, control of the cellular localization of the small RNR subunit, and regulation of RNR activity by small protein inhibitors. This review will focus on these additional mechanisms of control responsible for providing a balanced supply of dNTPs.
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Affiliation(s)
- Estrella Guarino
- Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
| | - Israel Salguero
- Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
| | - Stephen E Kearsey
- Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
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13
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Leffak M. Hypothesis: local dNTP depletion as the cause of microsatellite repeat instability during replication (comment on DOI 10.1002/bies.201200128). Bioessays 2014; 35:305. [PMID: 23494534 DOI: 10.1002/bies.201300026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Michael Leffak
- Wright State University - Biochemistry and Molecular Biology, Dayton, OH, USA.
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