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Sasani TA, Quinlan AR, Harris K. Epistasis between mutator alleles contributes to germline mutation spectrum variability in laboratory mice. eLife 2024; 12:RP89096. [PMID: 38381482 PMCID: PMC10942616 DOI: 10.7554/elife.89096] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024] Open
Abstract
Maintaining germline genome integrity is essential and enormously complex. Although many proteins are involved in DNA replication, proofreading, and repair, mutator alleles have largely eluded detection in mammals. DNA replication and repair proteins often recognize sequence motifs or excise lesions at specific nucleotides. Thus, we might expect that the spectrum of de novo mutations - the frequencies of C>T, A>G, etc. - will differ between genomes that harbor either a mutator or wild-type allele. Previously, we used quantitative trait locus mapping to discover candidate mutator alleles in the DNA repair gene Mutyh that increased the C>A germline mutation rate in a family of inbred mice known as the BXDs (Sasani et al., 2022, Ashbrook et al., 2021). In this study we developed a new method to detect alleles associated with mutation spectrum variation and applied it to mutation data from the BXDs. We discovered an additional C>A mutator locus on chromosome 6 that overlaps Ogg1, a DNA glycosylase involved in the same base-excision repair network as Mutyh (David et al., 2007). Its effect depends on the presence of a mutator allele near Mutyh, and BXDs with mutator alleles at both loci have greater numbers of C>A mutations than those with mutator alleles at either locus alone. Our new methods for analyzing mutation spectra reveal evidence of epistasis between germline mutator alleles and may be applicable to mutation data from humans and other model organisms.
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Affiliation(s)
- Thomas A Sasani
- Department of Human Genetics, University of UtahSalt Lake CityUnited States
| | - Aaron R Quinlan
- Department of Human Genetics, University of UtahSalt Lake CityUnited States
- Department of Biomedical Informatics, University of UtahSalt Lake CityUnited States
| | - Kelley Harris
- Department of Genome Sciences, University of WashingtonSeattleUnited States
- Herbold Computational Biology Program, Fred Hutch Cancer CenterSeattleUnited States
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2
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Nickoloff JA, Jaiswal AS, Sharma N, Williamson EA, Tran MT, Arris D, Yang M, Hromas R. Cellular Responses to Widespread DNA Replication Stress. Int J Mol Sci 2023; 24:16903. [PMID: 38069223 PMCID: PMC10707325 DOI: 10.3390/ijms242316903] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Replicative DNA polymerases are blocked by nearly all types of DNA damage. The resulting DNA replication stress threatens genome stability. DNA replication stress is also caused by depletion of nucleotide pools, DNA polymerase inhibitors, and DNA sequences or structures that are difficult to replicate. Replication stress triggers complex cellular responses that include cell cycle arrest, replication fork collapse to one-ended DNA double-strand breaks, induction of DNA repair, and programmed cell death after excessive damage. Replication stress caused by specific structures (e.g., G-rich sequences that form G-quadruplexes) is localized but occurs during the S phase of every cell division. This review focuses on cellular responses to widespread stress such as that caused by random DNA damage, DNA polymerase inhibition/nucleotide pool depletion, and R-loops. Another form of global replication stress is seen in cancer cells and is termed oncogenic stress, reflecting dysregulated replication origin firing and/or replication fork progression. Replication stress responses are often dysregulated in cancer cells, and this too contributes to ongoing genome instability that can drive cancer progression. Nucleases play critical roles in replication stress responses, including MUS81, EEPD1, Metnase, CtIP, MRE11, EXO1, DNA2-BLM, SLX1-SLX4, XPF-ERCC1-SLX4, Artemis, XPG, FEN1, and TATDN2. Several of these nucleases cleave branched DNA structures at stressed replication forks to promote repair and restart of these forks. We recently defined roles for EEPD1 in restarting stressed replication forks after oxidative DNA damage, and for TATDN2 in mitigating replication stress caused by R-loop accumulation in BRCA1-defective cells. We also discuss how insights into biological responses to genome-wide replication stress can inform novel cancer treatment strategies that exploit synthetic lethal relationships among replication stress response factors.
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Affiliation(s)
- Jac A. Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Aruna S. Jaiswal
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Elizabeth A. Williamson
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Manh T. Tran
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Dominic Arris
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Ming Yang
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Robert Hromas
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
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3
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Sasani TA, Quinlan AR, Harris K. Epistasis between mutator alleles contributes to germline mutation spectra variability in laboratory mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.25.537217. [PMID: 37162999 PMCID: PMC10168256 DOI: 10.1101/2023.04.25.537217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Maintaining germline genome integrity is essential and enormously complex. Although many proteins are involved in DNA replication, proofreading, and repair [1], mutator alleles have largely eluded detection in mammals. DNA replication and repair proteins often recognize sequence motifs or excise lesions at specific nucleotides. Thus, we might expect that the spectrum of de novo mutations - the frequencies of C>T, A>G, etc. - will differ between genomes that harbor either a mutator or wild-type allele. Previously, we used quantitative trait locus mapping to discover candidate mutator alleles in the DNA repair gene Mutyh that increased the C>A germline mutation rate in a family of inbred mice known as the BXDs [2,3]. In this study we developed a new method to detect alleles associated with mutation spectrum variation and applied it to mutation data from the BXDs. We discovered an additional C>A mutator locus on chromosome 6 that overlaps Ogg1, a DNA glycosylase involved in the same base-excision repair network as Mutyh [4]. Its effect depended on the presence of a mutator allele near Mutyh, and BXDs with mutator alleles at both loci had greater numbers of C>A mutations than those with mutator alleles at either locus alone. Our new methods for analyzing mutation spectra reveal evidence of epistasis between germline mutator alleles and may be applicable to mutation data from humans and other model organisms.
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Affiliation(s)
| | - Aaron R. Quinlan
- Department of Human Genetics, University of Utah; Department of Biomedical Informatics, University of Utah · Funded by NIH/NHGRI R01HG012252
| | - Kelley Harris
- Department of Genome Sciences, University of Washington · Funded by NIH/NIGMS R35GM133428; Burroughs Wellcome Career Award at the Scientific Interface; Searle Scholarship; Pew Scholarship; Sloan Fellowship; Allen Discovery Center for Cell Lineage Tracing
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Puzakov MV, Puzakova LV, Ulupova YN. Differential Activity of Genes with IS630/TC1/MARINER Transposon Fragments in the Genome of the Ctenophore Mnemiopsis leidyi. MOLECULAR GENETICS, MICROBIOLOGY AND VIROLOGY 2022. [DOI: 10.3103/s089141682204005x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/22/2023]
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5
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Structural and genome-wide analyses suggest that transposon-derived protein SETMAR alters transcription and splicing. J Biol Chem 2022; 298:101894. [PMID: 35378129 PMCID: PMC9062482 DOI: 10.1016/j.jbc.2022.101894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 03/25/2022] [Accepted: 03/26/2022] [Indexed: 11/22/2022] Open
Abstract
Extensive portions of the human genome have unknown function, including those derived from transposable elements. One such element, the DNA transposon Hsmar1, entered the primate lineage approximately 50 million years ago leaving behind terminal inverted repeat (TIR) sequences and a single intact copy of the Hsmar1 transposase, which retains its ancestral TIR-DNA-binding activity, and is fused with a lysine methyltransferase SET domain to constitute the chimeric SETMAR gene. Here, we provide a structural basis for recognition of TIRs by SETMAR and investigate the function of SETMAR through genome-wide approaches. As elucidated in our 2.37 Å crystal structure, SETMAR forms a dimeric complex with each DNA-binding domain bound specifically to TIR-DNA through the formation of 32 hydrogen bonds. We found that SETMAR recognizes primarily TIR sequences (∼5000 sites) within the human genome as assessed by chromatin immunoprecipitation sequencing analysis. In two SETMAR KO cell lines, we identified 163 shared differentially expressed genes and 233 shared alternative splicing events. Among these genes are several pre–mRNA-splicing factors, transcription factors, and genes associated with neuronal function, and one alternatively spliced primate-specific gene, TMEM14B, which has been identified as a marker for neocortex expansion associated with brain evolution. Taken together, our results suggest a model in which SETMAR impacts differential expression and alternative splicing of genes associated with transcription and neuronal function, potentially through both its TIR-specific DNA-binding and lysine methyltransferase activities, consistent with a role for SETMAR in simian primate development.
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Nickoloff JA, Sharma N, Taylor L, Allen SJ, Hromas R. Nucleases and Co-Factors in DNA Replication Stress Responses. DNA 2022; 2:68-85. [PMID: 36203968 PMCID: PMC9534323 DOI: 10.3390/dna2010006] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
DNA replication stress is a constant threat that cells must manage to proliferate and maintain genome integrity. DNA replication stress responses, a subset of the broader DNA damage response (DDR), operate when the DNA replication machinery (replisome) is blocked or replication forks collapse during S phase. There are many sources of replication stress, such as DNA lesions caused by endogenous and exogenous agents including commonly used cancer therapeutics, and difficult-to-replicate DNA sequences comprising fragile sites, G-quadraplex DNA, hairpins at trinucleotide repeats, and telomeres. Replication stress is also a consequence of conflicts between opposing transcription and replication, and oncogenic stress which dysregulates replication origin firing and fork progression. Cells initially respond to replication stress by protecting blocked replisomes, but if the offending problem (e.g., DNA damage) is not bypassed or resolved in a timely manner, forks may be cleaved by nucleases, inducing a DNA double-strand break (DSB) and providing a means to accurately restart stalled forks via homologous recombination. However, DSBs pose their own risks to genome stability if left unrepaired or misrepaired. Here we focus on replication stress response systems, comprising DDR signaling, fork protection, and fork processing by nucleases that promote fork repair and restart. Replication stress nucleases include MUS81, EEPD1, Metnase, CtIP, MRE11, EXO1, DNA2-BLM, SLX1-SLX4, XPF-ERCC1-SLX4, Artemis, XPG, and FEN1. Replication stress factors are important in cancer etiology as suppressors of genome instability associated with oncogenic mutations, and as potential cancer therapy targets to enhance the efficacy of chemo- and radiotherapeutics.
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Affiliation(s)
- Jac A. Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Lynn Taylor
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Sage J. Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX 78229, USA
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Nickoloff JA, Sharma N, Taylor L, Allen SJ, Lee SH, Hromas R. Metnase and EEPD1: DNA Repair Functions and Potential Targets in Cancer Therapy. Front Oncol 2022; 12:808757. [PMID: 35155245 PMCID: PMC8831698 DOI: 10.3389/fonc.2022.808757] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/12/2022] [Indexed: 12/30/2022] Open
Abstract
Cells respond to DNA damage by activating signaling and DNA repair systems, described as the DNA damage response (DDR). Clarifying DDR pathways and their dysregulation in cancer are important for understanding cancer etiology, how cancer cells exploit the DDR to survive endogenous and treatment-related stress, and to identify DDR targets as therapeutic targets. Cancer is often treated with genotoxic chemicals and/or ionizing radiation. These agents are cytotoxic because they induce DNA double-strand breaks (DSBs) directly, or indirectly by inducing replication stress which causes replication fork collapse to DSBs. EEPD1 and Metnase are structure-specific nucleases, and Metnase is also a protein methyl transferase that methylates histone H3 and itself. EEPD1 and Metnase promote repair of frank, two-ended DSBs, and both promote the timely and accurate restart of replication forks that have collapsed to single-ended DSBs. In addition to its roles in HR, Metnase also promotes DSB repair by classical non-homologous recombination, and chromosome decatenation mediated by TopoIIα. Although mutations in Metnase and EEPD1 are not common in cancer, both proteins are frequently overexpressed, which may help tumor cells manage oncogenic stress or confer resistance to therapeutics. Here we focus on Metnase and EEPD1 DNA repair pathways, and discuss opportunities for targeting these pathways to enhance cancer therapy.
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Affiliation(s)
- Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Lynn Taylor
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Sage J Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, United States
| | - Suk-Hee Lee
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX, United States
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Tellier M. Structure, Activity, and Function of SETMAR Protein Lysine Methyltransferase. Life (Basel) 2021; 11:life11121342. [PMID: 34947873 PMCID: PMC8704517 DOI: 10.3390/life11121342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 12/21/2022] Open
Abstract
SETMAR is a protein lysine methyltransferase that is involved in several DNA processes, including DNA repair via the non-homologous end joining (NHEJ) pathway, regulation of gene expression, illegitimate DNA integration, and DNA decatenation. However, SETMAR is an atypical protein lysine methyltransferase since in anthropoid primates, the SET domain is fused to an inactive DNA transposase. The presence of the DNA transposase domain confers to SETMAR a DNA binding activity towards the remnants of its transposable element, which has resulted in the emergence of a gene regulatory function. Both the SET and the DNA transposase domains are involved in the different cellular roles of SETMAR, indicating the presence of novel and specific functions in anthropoid primates. In addition, SETMAR is dysregulated in different types of cancer, indicating a potential pathological role. While some light has been shed on SETMAR functions, more research and new tools are needed to better understand the cellular activities of SETMAR and to investigate the therapeutic potential of SETMAR.
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Affiliation(s)
- Michael Tellier
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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9
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Nickoloff JA, Sharma N, Taylor L, Allen SJ, Hromas R. The Safe Path at the Fork: Ensuring Replication-Associated DNA Double-Strand Breaks are Repaired by Homologous Recombination. Front Genet 2021; 12:748033. [PMID: 34646312 PMCID: PMC8502867 DOI: 10.3389/fgene.2021.748033] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/14/2021] [Indexed: 01/15/2023] Open
Abstract
Cells must replicate and segregate their DNA to daughter cells accurately to maintain genome stability and prevent cancer. DNA replication is usually fast and accurate, with intrinsic (proofreading) and extrinsic (mismatch repair) error-correction systems. However, replication forks slow or stop when they encounter DNA lesions, natural pause sites, and difficult-to-replicate sequences, or when cells are treated with DNA polymerase inhibitors or hydroxyurea, which depletes nucleotide pools. These challenges are termed replication stress, to which cells respond by activating DNA damage response signaling pathways that delay cell cycle progression, stimulate repair and replication fork restart, or induce apoptosis. Stressed forks are managed by rescue from adjacent forks, repriming, translesion synthesis, template switching, and fork reversal which produces a single-ended double-strand break (seDSB). Stressed forks also collapse to seDSBs when they encounter single-strand nicks or are cleaved by structure-specific nucleases. Reversed and cleaved forks can be restarted by homologous recombination (HR), but seDSBs pose risks of mis-rejoining by non-homologous end-joining (NHEJ) to other DSBs, causing genome rearrangements. HR requires resection of broken ends to create 3' single-stranded DNA for RAD51 recombinase loading, and resected ends are refractory to repair by NHEJ. This Mini Review highlights mechanisms that help maintain genome stability by promoting resection of seDSBs and accurate fork restart by HR.
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Affiliation(s)
- Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO, United States
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO, United States
| | - Lynn Taylor
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO, United States
| | - Sage J Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO, United States
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX, United States
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Nickoloff JA, Sharma N, Allen CP, Taylor L, Allen SJ, Jaiswal AS, Hromas R. Roles of homologous recombination in response to ionizing radiation-induced DNA damage. Int J Radiat Biol 2021; 99:903-914. [PMID: 34283012 PMCID: PMC9629169 DOI: 10.1080/09553002.2021.1956001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/04/2021] [Accepted: 07/05/2021] [Indexed: 02/06/2023]
Abstract
PURPOSE Ionizing radiation induces a vast array of DNA lesions including base damage, and single- and double-strand breaks (SSB, DSB). DSBs are among the most cytotoxic lesions, and mis-repair causes small- and large-scale genome alterations that can contribute to carcinogenesis. Indeed, ionizing radiation is a 'complete' carcinogen. DSBs arise immediately after irradiation, termed 'frank DSBs,' as well as several hours later in a replication-dependent manner, termed 'secondary' or 'replication-dependent DSBs. DSBs resulting from replication fork collapse are single-ended and thus pose a distinct problem from two-ended, frank DSBs. DSBs are repaired by error-prone nonhomologous end-joining (NHEJ), or generally error-free homologous recombination (HR), each with sub-pathways. Clarifying how these pathways operate in normal and tumor cells is critical to increasing tumor control and minimizing side effects during radiotherapy. CONCLUSIONS The choice between NHEJ and HR is regulated during the cell cycle and by other factors. DSB repair pathways are major contributors to cell survival after ionizing radiation, including tumor-resistance to radiotherapy. Several nucleases are important for HR-mediated repair of replication-dependent DSBs and thus replication fork restart. These include three structure-specific nucleases, the 3' MUS81 nuclease, and two 5' nucleases, EEPD1 and Metnase, as well as three end-resection nucleases, MRE11, EXO1, and DNA2. The three structure-specific nucleases evolved at very different times, suggesting incremental acceleration of replication fork restart to limit toxic HR intermediates and genome instability as genomes increased in size during evolution, including the gain of large numbers of HR-prone repetitive elements. Ionizing radiation also induces delayed effects, observed days to weeks after exposure, including delayed cell death and delayed HR. In this review we highlight the roles of HR in cellular responses to ionizing radiation, and discuss the importance of HR as an exploitable target for cancer radiotherapy.
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Affiliation(s)
- Jac A. Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Christopher P. Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
- Department of Microbiology, Immunology and Pathology, Flow Cytometry and Cell Sorting Facility, Colorado State University, Fort Collins, CO, USA
| | - Lynn Taylor
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Sage J. Allen
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Aruna S. Jaiswal
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX, USA
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine and the Mays Cancer Center, University of Texas Health Science Center, San Antonio, TX, USA
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Sharma V, Thakore P, Majumdar S. THAP9 Transposase Cleaves DNA via Conserved Acidic Residues in an RNaseH-Like Domain. Cells 2021; 10:1351. [PMID: 34072453 PMCID: PMC8230255 DOI: 10.3390/cells10061351] [Citation(s) in RCA: 1] [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] [Received: 04/09/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 11/16/2022] Open
Abstract
The catalytic domain of most 'cut and paste' DNA transposases have the canonical RNase-H fold, which is also shared by other polynucleotidyl transferases such as the retroviral integrases and the RAG1 subunit of V(D)J recombinase. The RNase-H fold is a mixture of beta sheets and alpha helices with three acidic residues (Asp, Asp, Glu/Asp-DDE/D) that are involved in the metal-mediated cleavage and subsequent integration of DNA. Human THAP9 (hTHAP9), homologous to the well-studied Drosophila P-element transposase (DmTNP), is an active DNA transposase that, although domesticated, still retains the catalytic activity to mobilize transposons. In this study we have modeled the structure of hTHAP9 using the recently available cryo-EM structure of DmTNP as a template to identify an RNase-H like fold along with important acidic residues in its catalytic domain. Site-directed mutagenesis of the predicted catalytic residues followed by screening for DNA excision and integration activity has led to the identification of candidate Ds and Es in the RNaseH fold that may be a part of the catalytic triad in hTHAP9. This study has helped widen our knowledge about the catalytic activity of a functionally uncharacterized transposon-derived gene in the human genome.
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Affiliation(s)
| | | | - Sharmistha Majumdar
- Discipline of Biological Engineering, Indian Institute of Technology Gandhinagar, Gujarat 382355, India; (V.S.); (P.T.)
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Antoine-Lorquin A, Arensburger P, Arnaoty A, Asgari S, Batailler M, Beauclair L, Belleannée C, Buisine N, Coustham V, Guyetant S, Helou L, Lecomte T, Pitard B, Stévant I, Bigot Y. Two repeated motifs enriched within some enhancers and origins of replication are bound by SETMAR isoforms in human colon cells. Genomics 2021; 113:1589-1604. [PMID: 33812898 DOI: 10.1016/j.ygeno.2021.03.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 03/25/2021] [Accepted: 03/30/2021] [Indexed: 11/15/2022]
Abstract
Setmar is a gene specific to simian genomes. The function(s) of its isoforms are poorly understood and their existence in healthy tissues remains to be validated. Here we profiled SETMAR expression and its genome-wide binding landscape in colon tissue. We found isoforms V3 and V6 in healthy and tumour colon tissues as well as incell lines. In two colorectal cell lines SETMAR binds to several thousand Hsmar1 and MADE1 terminal ends, transposons mostly located in non-genic regions of active chromatin including in enhancers. It also binds to a 12-bp motifs similar to an inner motif in Hsmar1 and MADE1 terminal ends. This motif is interspersed throughout the genome and is enriched in GC-rich regions as well as in CpG islands that contain constitutive replication origins. It is also found in enhancers other than those associated with Hsmar1 and MADE1. The role of SETMAR in the expression of genes, DNA replication and in DNA repair are discussed.
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Affiliation(s)
| | - Peter Arensburger
- Biological Sciences Department, California State Polytechnic University, Pomona, CA 91768, - United States
| | - Ahmed Arnaoty
- EA GICC, 7501, CHRU de Tours, 37044 TOURS, Cedex 09, France
| | - Sassan Asgari
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Martine Batailler
- PRC, UMR INRA 0085, CNRS 7247, Centre INRA Val de Loire, 37380 Nouzilly, France
| | - Linda Beauclair
- PRC, UMR INRA 0085, CNRS 7247, Centre INRA Val de Loire, 37380 Nouzilly, France
| | | | - Nicolas Buisine
- UMR CNRS 7221, Muséum National d'Histoire Naturelle, 75005 Paris, France
| | | | - Serge Guyetant
- Tumorothèque du CHRU de Tours, 37044 Tours, Cedex, France
| | - Laura Helou
- PRC, UMR INRA 0085, CNRS 7247, Centre INRA Val de Loire, 37380 Nouzilly, France
| | | | - Bruno Pitard
- Université de Nantes, CNRS ERL6001, Inserm 1232, CRCINA, F-44000 Nantes, France
| | - Isabelle Stévant
- Institut de Génomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon, 1, 46 allée d'Italie, 69364 Lyon, France
| | - Yves Bigot
- PRC, UMR INRA 0085, CNRS 7247, Centre INRA Val de Loire, 37380 Nouzilly, France.
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Sharma N, Speed MC, Allen CP, Maranon DG, Williamson E, Singh S, Hromas R, Nickoloff JA. Distinct roles of structure-specific endonucleases EEPD1 and Metnase in replication stress responses. NAR Cancer 2020; 2:zcaa008. [PMID: 32743552 PMCID: PMC7380491 DOI: 10.1093/narcan/zcaa008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 05/20/2020] [Accepted: 05/31/2020] [Indexed: 12/16/2022] Open
Abstract
Accurate DNA replication and segregation are critical for maintaining genome integrity and suppressing cancer. Metnase and EEPD1 are DNA damage response (DDR) proteins frequently dysregulated in cancer and implicated in cancer etiology and tumor response to genotoxic chemo- and radiotherapy. Here, we examine the DDR in human cell lines with CRISPR/Cas9 knockout of Metnase or EEPD1. The knockout cell lines exhibit slightly slower growth rates, significant hypersensitivity to replication stress, increased genome instability and distinct alterations in DDR signaling. Metnase and EEPD1 are structure-specific nucleases. EEPD1 is recruited to and cleaves stalled forks to initiate fork restart by homologous recombination. Here, we demonstrate that Metnase is also recruited to stalled forks where it appears to dimethylate histone H3 lysine 36 (H3K36me2), raising the possibility that H3K36me2 promotes DDR factor recruitment or limits nucleosome eviction to protect forks from nucleolytic attack. We show that stalled forks are cleaved normally in the absence of Metnase, an important and novel result because a prior study indicated that Metnase nuclease is important for timely fork restart. A double knockout was as sensitive to etoposide as either single knockout, suggesting a degree of epistasis between Metnase and EEPD1. We propose that EEPD1 initiates fork restart by cleaving stalled forks, and that Metnase may promote fork restart by processing homologous recombination intermediates and/or inducing H3K36me2 to recruit DDR factors. By accelerating fork restart, Metnase and EEPD1 reduce the chance that stalled replication forks will adopt toxic or genome-destabilizing structures, preventing genome instability and cancer. Metnase and EEPD1 are overexpressed in some cancers and thus may also promote resistance to genotoxic therapeutics.
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Affiliation(s)
- Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, 1618 Campus Delivery, Fort Collins, CO 80523-1618, USA
| | - Michael C Speed
- Department of Environmental and Radiological Health Sciences, Colorado State University, 1618 Campus Delivery, Fort Collins, CO 80523-1618, USA
| | - Christopher P Allen
- Department of Microbiology, Immunology, and Pathology, Colorado State University, 1601Campus Delivery, Fort Collins, CO 80523-1601, USA
| | - David G Maranon
- Department of Environmental and Radiological Health Sciences, Colorado State University, 1618 Campus Delivery, Fort Collins, CO 80523-1618, USA
| | - Elizabeth Williamson
- Division of Hematology and Medical Oncology, Department of Medicine, University of Texas HealthScience Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Sudha Singh
- Division of Hematology and Medical Oncology, Department of Medicine, University of Texas HealthScience Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Robert Hromas
- Division of Hematology and Medical Oncology, Department of Medicine, University of Texas HealthScience Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, 1618 Campus Delivery, Fort Collins, CO 80523-1618, USA
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14
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The Tc1-like elements with the spliceosomal introns in mollusk genomes. Mol Genet Genomics 2020; 295:621-633. [DOI: 10.1007/s00438-020-01645-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 01/09/2020] [Indexed: 12/22/2022]
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15
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Tellier M, Chalmers R. The roles of the human SETMAR (Metnase) protein in illegitimate DNA recombination and non-homologous end joining repair. DNA Repair (Amst) 2019; 80:26-35. [PMID: 31238295 PMCID: PMC6715855 DOI: 10.1016/j.dnarep.2019.06.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/18/2019] [Accepted: 06/18/2019] [Indexed: 02/07/2023]
Abstract
Full length SETMAR expression has no effect on DNA repair and integration in vivo. SETMAR putative nuclease activity is not required in vivo. Separate expression of the SET and MAR domains affects DNA repair and integration. SETMAR isoform with a truncated SET-domain is specific to species containing the MAR domain.
SETMAR is a fusion between a SET-domain methyltransferase gene and a mariner-family transposase gene, which is specific to anthropoid primates. However, the ancestral SET gene is present in all other mammals and birds. SETMAR is reported to be involved in transcriptional regulation and a diverse set of reactions related to DNA repair. Since the transcriptional effects of SETMAR depend on site-specific DNA binding, and are perturbed by inactivating the methyltransferase, we wondered whether we could differentiate the effects of the SET and MAR domains in DNA repair assays. We therefore generated several stable U2OS cell lines expressing either wild type SETMAR or truncation or point mutant variants. We tested these cell lines with in vivo plasmid-based assays to determine the relevance of the different domains and activities of SETMAR in DNA repair. Contrary to previous reports, we found that wild type SETMAR had little to no effect on the rate of cell division, DNA integration into the genome or non-homologous end joining. Also contrary to previous reports, we failed to detect any effect of a strong active-site mutation that should have knocked out the putative nuclease activity of SETMAR.
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Affiliation(s)
- Michael Tellier
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
| | - Ronald Chalmers
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
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16
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Bischerour J, Bhullar S, Denby Wilkes C, Régnier V, Mathy N, Dubois E, Singh A, Swart E, Arnaiz O, Sperling L, Nowacki M, Bétermier M. Six domesticated PiggyBac transposases together carry out programmed DNA elimination in Paramecium. eLife 2018; 7:37927. [PMID: 30223944 PMCID: PMC6143343 DOI: 10.7554/elife.37927] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/29/2018] [Indexed: 02/06/2023] Open
Abstract
The domestication of transposable elements has repeatedly occurred during evolution and domesticated transposases have often been implicated in programmed genome rearrangements, as remarkably illustrated in ciliates. In Paramecium, PiggyMac (Pgm), a domesticated PiggyBac transposase, carries out developmentally programmed DNA elimination, including the precise excision of tens of thousands of gene-interrupting germline Internal Eliminated Sequences (IESs). Here, we report the discovery of five groups of distant Pgm-like proteins (PgmLs), all able to interact with Pgm and essential for its nuclear localization and IES excision genome-wide. Unlike Pgm, PgmLs lack a conserved catalytic site, suggesting that they rather have an architectural function within a multi-component excision complex embedding Pgm. PgmL depletion can increase erroneous targeting of residual Pgm-mediated DNA cleavage, indicating that PgmLs contribute to accurately position the complex on IES ends. DNA rearrangements in Paramecium constitute a rare example of a biological process jointly managed by six distinct domesticated transposases.
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Affiliation(s)
- Julien Bischerour
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Simran Bhullar
- Institute of Cell Biology, University of Bern, Bern, Switzerland.,Institut de Biologie de l'Ecole Normale Supérieure, Paris, France
| | - Cyril Denby Wilkes
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Vinciane Régnier
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France.,Univ Paris Diderot, Paris, France
| | - Nathalie Mathy
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Emeline Dubois
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Aditi Singh
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Estienne Swart
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Olivier Arnaiz
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Linda Sperling
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Mariusz Nowacki
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Mireille Bétermier
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
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17
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Hromas R, Kim HS, Sidhu G, Williamson E, Jaiswal A, Totterdale TA, Nole J, Lee SH, Nickoloff JA, Kong KY. The endonuclease EEPD1 mediates synthetic lethality in RAD52-depleted BRCA1 mutant breast cancer cells. Breast Cancer Res 2017; 19:122. [PMID: 29145865 PMCID: PMC5693420 DOI: 10.1186/s13058-017-0912-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 10/30/2017] [Indexed: 02/06/2023] Open
Abstract
Background Proper repair and restart of stressed replication forks requires intact homologous recombination (HR). HR at stressed replication forks can be initiated by the 5′ endonuclease EEPD1, which cleaves the stalled replication fork. Inherited or acquired defects in HR, such as mutations in breast cancer susceptibility protein-1 (BRCA1) or BRCA2, predispose to cancer, including breast and ovarian cancers. In order for these HR-deficient tumor cells to proliferate, they become addicted to a bypass replication fork repair pathway mediated by radiation repair protein 52 (RAD52). Depleting RAD52 can cause synthetic lethality in BRCA1/2 mutant cancers by an unknown molecular mechanism. Methods We hypothesized that cleavage of stressed replication forks by EEPD1 generates a fork repair intermediate that is toxic when HR-deficient cells cannot complete repair with the RAD52 bypass pathway. To test this hypothesis, we applied cell survival assays, immunofluorescence staining, DNA fiber and western blot analyses to look at the correlation between cell survival and genome integrity in control, EEPD1, RAD52 and EEPD1/RAD52 co-depletion BRCA1-deficient breast cancer cells. Results Our data show that depletion of EEPD1 suppresses synthetic lethality, genome instability, mitotic catastrophe, and hypersensitivity to stress of replication of RAD52-depleted, BRCA1 mutant breast cancer cells. Without HR and the RAD52-dependent backup pathway, the BRCA1 mutant cancer cells depleted of EEPD1 skew to the alternative non-homologous end-joining DNA repair pathway for survival. Conclusion This study indicates that the mechanism of synthetic lethality in RAD52-depleted BRCA1 mutant cancer cells depends on the endonuclease EEPD1. The data imply that EEPD1 cleavage of stressed replication forks may result in a toxic intermediate when replication fork repair cannot be completed. Electronic supplementary material The online version of this article (doi:10.1186/s13058-017-0912-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Robert Hromas
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA.
| | - Hyun-Suk Kim
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Gurjit Sidhu
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
| | - Elizabeth Williamson
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
| | - Aruna Jaiswal
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
| | - Taylor A Totterdale
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
| | - Jocelyn Nole
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
| | - Suk-Hee Lee
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Kimi Y Kong
- Department of Medicine and the Cancer Center, University of Florida Health, 1600 SW Archer Rd, Gainesville, FL, 32610, USA.
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18
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Nickoloff JA, Jones D, Lee SH, Williamson EA, Hromas R. Drugging the Cancers Addicted to DNA Repair. J Natl Cancer Inst 2017; 109:3832892. [PMID: 28521333 PMCID: PMC5436301 DOI: 10.1093/jnci/djx059] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 03/10/2017] [Indexed: 12/29/2022] Open
Abstract
Defects in DNA repair can result in oncogenic genomic instability. Cancers occurring from DNA repair defects were once thought to be limited to rare inherited mutations (such as BRCA1 or 2). It now appears that a clinically significant fraction of cancers have acquired DNA repair defects. DNA repair pathways operate in related networks, and cancers arising from loss of one DNA repair component typically become addicted to other repair pathways to survive and proliferate. Drug inhibition of the rescue repair pathway prevents the repair-deficient cancer cell from replicating, causing apoptosis (termed synthetic lethality). However, the selective pressure of inhibiting the rescue repair pathway can generate further mutations that confer resistance to the synthetic lethal drugs. Many such drugs currently in clinical use inhibit PARP1, a repair component to which cancers arising from inherited BRCA1 or 2 mutations become addicted. It is now clear that drugs inducing synthetic lethality may also be therapeutic in cancers with acquired DNA repair defects, which would markedly broaden their applicability beyond treatment of cancers with inherited DNA repair defects. Here we review how each DNA repair pathway can be attacked therapeutically and evaluate DNA repair components as potential drug targets to induce synthetic lethality. Clinical use of drugs targeting DNA repair will markedly increase when functional and genetic loss of repair components are consistently identified. In addition, future therapies will exploit artificial synthetic lethality, where complementary DNA repair pathways are targeted simultaneously in cancers without DNA repair defects.
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Affiliation(s)
- Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA
| | - Dennie Jones
- Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, FL, USA
| | - Suk-Hee Lee
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Elizabeth A Williamson
- Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, FL, USA
| | - Robert Hromas
- Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, FL, USA
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19
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Paths from DNA damage and signaling to genome rearrangements via homologous recombination. Mutat Res 2017; 806:64-74. [PMID: 28779875 DOI: 10.1016/j.mrfmmm.2017.07.008] [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: 11/07/2016] [Accepted: 07/21/2017] [Indexed: 12/31/2022]
Abstract
DNA damage is a constant threat to genome integrity. DNA repair and damage signaling networks play a central role maintaining genome stability, suppressing tumorigenesis, and determining tumor response to common cancer chemotherapeutic agents and radiotherapy. DNA double-strand breaks (DSBs) are critical lesions induced by ionizing radiation and when replication forks encounter damage. DSBs can result in mutations and large-scale genome rearrangements reflecting mis-repair by non-homologous end joining or homologous recombination. Ionizing radiation induces genetic change immediately, and it also triggers delayed events weeks or even years after exposure, long after the initial damage has been repaired or diluted through cell division. This review covers DNA damage signaling and repair pathways and cell fate following genotoxic insult, including immediate and delayed genome instability and cell survival/cell death pathways.
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20
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Nickoloff JA, Boss MK, Allen CP, LaRue SM. Translational research in radiation-induced DNA damage signaling and repair. Transl Cancer Res 2017; 6:S875-S891. [PMID: 30574452 PMCID: PMC6298755 DOI: 10.21037/tcr.2017.06.02] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Radiotherapy is an effective tool in the fight against cancer. It is non-invasive and painless, and with advanced tumor imaging and beam control systems, radiation can be delivered to patients safely, generally with minor or no adverse side effects, accounting for its increasing use against a broad range of tumors. Tumors and normal cells respond to radiation-induced DNA damage by activating a complex network of DNA damage signaling and repair pathways that determine cell fate including survival, death, and genome stability. DNA damage response (DDR) proteins represent excellent targets to augment radiotherapy, and many agents that inhibit key response proteins are being combined with radiation and genotoxic chemotherapy in clinical trials. This review focuses on how insights into molecular mechanisms of DDR pathways are translated to small animal preclinical studies, to clinical studies of naturally occurring tumors in companion animals, and finally to human clinical trials. Companion animal studies, under the umbrella of comparative oncology, have played key roles in the development of clinical radiotherapy throughout its >100-year history. There is growing appreciation that rapid translation of basic knowledge of DNA damage and repair systems to improved radiotherapy practice requires a comprehensive approach that embraces the full spectrum of cancer research, with companion animal clinical trials representing a critical bridge between small animal preclinical studies, and human clinical trials.
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Affiliation(s)
- Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Flint Animal Cancer Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Mary-Keara Boss
- Department of Environmental and Radiological Health Sciences, Flint Animal Cancer Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Christopher P Allen
- Department of Environmental and Radiological Health Sciences, Flint Animal Cancer Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Susan M LaRue
- Department of Environmental and Radiological Health Sciences, Flint Animal Cancer Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
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21
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Dussaussois-Montagne A, Jaillet J, Babin L, Verrelle P, Karayan-Tapon L, Renault S, Rousselot-Denis C, Zemmoura I, Augé-Gouillou C. SETMAR isoforms in glioblastoma: A matter of protein stability. Oncotarget 2017; 8:9835-9848. [PMID: 28038463 PMCID: PMC5354774 DOI: 10.18632/oncotarget.14218] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 12/05/2016] [Indexed: 01/10/2023] Open
Abstract
Glioblastomas (GBMs) are the most frequent and the most aggressive brain tumors, known for their chemo- and radio-resistance, making them often incurable. We also know that SETMAR is a protein involved in chromatin dynamics and genome plasticity, of which overexpression confers chemo- and radio-resistance to some tumors. The relationships between SETMAR and GBM have never been explored. To fill this gap, we define the SETMAR status of 44 resected tumors and of GBM derived cells, at both the mRNA and the protein levels. We identify a new, small SETMAR protein (so called SETMAR-1200), enriched in GBMs and GBM stem cells as compared to the regular enzyme (SETMAR-2100). We show that SETMAR-1200 is able to increase DNA repair by non-homologous end-joining, albeit with a lower efficiency than the regular SETMAR protein. Interestingly, the regular/small ratio of SETMAR in GBM cells changes depending on cell type, providing evidence that SETMAR expression is regulated by alternative splicing. We also demonstrate that SETMAR expression can be regulated by the use of an alternative ATG. In conclusion, various SETMAR proteins can be synthesized in human GBM that may each have specific biophysical and/or biochemical properties and characteristics. Among them, the small SETMAR may play a role in GBMs biogenesis. On this basis, we would like to consider SETMAR-1200 as a new potential therapeutic target to investigate, in addition to the regular SETMAR protein already considered by others.
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Affiliation(s)
| | - Jérôme Jaillet
- EA 6306 IGC, University François Rabelais, 37200 Tours, France
| | - Laetitia Babin
- EA 6306 IGC, University François Rabelais, 37200 Tours, France
- UMR CNRS 7292 GICC, University François Rabelais, 37000 Tours, France
| | - Pierre Verrelle
- EA 7283 CREaT, Université d′Auvergne, BP 10448, 63000 Clermont-Ferrand, France
- Institut Curie, Dpt d'Oncologie Radiothérapique, 75005 Paris, France
- Centre Jean Perrin, Service Radiothérapie, Laboratoire de Radio-Oncologie Expérimentale, 63000 Clermont-Ferrand, France
| | - Lucie Karayan-Tapon
- INSERM U1084, Laboratoire de Neurosciences Expérimentales et Cliniques, F-86021 Poitiers, France
- University of Poitiers, F-86022 Poitiers, France
- CHU of Poitiers, Laboratoire de Cancérologie Biologique, F-86021 Poitiers, France
| | | | | | - Ilyess Zemmoura
- INSERM U930 Imagerie & Cerveau, University François Rabelais, 37000 Tours, France
- CHRU of Tours, Service de Neurochirurgie, 37000 Tours, France
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22
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Kim HS, Nickoloff JA, Wu Y, Williamson EA, Sidhu GS, Reinert BL, Jaiswal AS, Srinivasan G, Patel B, Kong K, Burma S, Lee SH, Hromas RA. Endonuclease EEPD1 Is a Gatekeeper for Repair of Stressed Replication Forks. J Biol Chem 2017; 292:2795-2804. [PMID: 28049724 PMCID: PMC5314175 DOI: 10.1074/jbc.m116.758235] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 12/29/2016] [Indexed: 01/21/2023] Open
Abstract
Replication is not as continuous as once thought, with DNA damage frequently stalling replication forks. Aberrant repair of stressed replication forks can result in cell death or genome instability and resulting transformation to malignancy. Stressed replication forks are most commonly repaired via homologous recombination (HR), which begins with 5′ end resection, mediated by exonuclease complexes, one of which contains Exo1. However, Exo1 requires free 5′-DNA ends upon which to act, and these are not commonly present in non-reversed stalled replication forks. To generate a free 5′ end, stalled replication forks must therefore be cleaved. Although several candidate endonucleases have been implicated in cleavage of stalled replication forks to permit end resection, the identity of such an endonuclease remains elusive. Here we show that the 5′-endonuclease EEPD1 cleaves replication forks at the junction between the lagging parental strand and the unreplicated DNA parental double strands. This cleavage creates the structure that Exo1 requires for 5′ end resection and HR initiation. We observed that EEPD1 and Exo1 interact constitutively, and Exo1 repairs stalled replication forks poorly without EEPD1. Thus, EEPD1 performs a gatekeeper function for replication fork repair by mediating the fork cleavage that permits initiation of HR-mediated repair and restart of stressed forks.
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Affiliation(s)
- Hyun-Suk Kim
- From the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Jac A Nickoloff
- the Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523
| | - Yuehan Wu
- the Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida 32610, and
| | - Elizabeth A Williamson
- the Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida 32610, and
| | - Gurjit Singh Sidhu
- the Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida 32610, and
| | - Brian L Reinert
- the Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida 32610, and
| | - Aruna S Jaiswal
- the Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida 32610, and
| | - Gayathri Srinivasan
- the Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida 32610, and
| | - Bhavita Patel
- the Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida 32610, and
| | - Kimi Kong
- the Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida 32610, and
| | - Sandeep Burma
- the Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Suk-Hee Lee
- From the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202,
| | - Robert A Hromas
- the Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida 32610, and
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23
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Kim HS, Williamson EA, Nickoloff JA, Hromas RA, Lee SH. Metnase Mediates Loading of Exonuclease 1 onto Single Strand Overhang DNA for End Resection at Stalled Replication Forks. J Biol Chem 2016; 292:1414-1425. [PMID: 27974460 DOI: 10.1074/jbc.m116.745646] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 12/13/2016] [Indexed: 11/06/2022] Open
Abstract
Stalling at DNA replication forks generates stretches of single-stranded (ss) DNA on both strands that are exposed to nucleolytic degradation, potentially compromising genome stability. One enzyme crucial for DNA replication fork repair and restart of stalled forks in human is Metnase (also known as SETMAR), a chimeric fusion protein consisting of a su(var)3-9, enhancer-of-zeste and trithorax (SET) histone methylase and transposase nuclease domain. We previously showed that Metnase possesses a unique fork cleavage activity necessary for its function in replication restart and that its SET domain is essential for recovery from hydroxyurea-induced DNA damage. However, its exact role in replication restart is unclear. In this study, we show that Metnase associates with exonuclease 1 (Exo1), a 5'-exonuclease crucial for 5'-end resection to mediate DNA processing at stalled forks. Metnase DNA cleavage activity was not required for Exo1 5'-exonuclease activity on the lagging strand daughter DNA, but its DNA binding activity mediated loading of Exo1 onto ssDNA overhangs. Metnase-induced enhancement of Exo1-mediated DNA strand resection required the presence of these overhangs but did not require Metnase's DNA cleavage activity. These results suggest that Metnase enhances Exo1-mediated exonuclease activity on the lagging strand DNA by facilitating Exo1 loading onto a single strand gap at the stalled replication fork.
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Affiliation(s)
- Hyun-Suk Kim
- From the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Elizabeth A Williamson
- the Department of Medicine, University of Florida and Shands Health Care System, Gainesville, Florida 32610, and
| | - Jac A Nickoloff
- the Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523
| | - Robert A Hromas
- the Department of Medicine, University of Florida and Shands Health Care System, Gainesville, Florida 32610, and
| | - Suk-Hee Lee
- From the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202,
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24
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Chen Q, Georgiadis M. Crystallization of and selenomethionine phasing strategy for a SETMAR-DNA complex. Acta Crystallogr F Struct Biol Commun 2016; 72:713-9. [PMID: 27599863 PMCID: PMC5012212 DOI: 10.1107/s2053230x16012723] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 08/06/2016] [Indexed: 11/10/2022] Open
Abstract
Transposable elements have played a critical role in the creation of new genes in all higher eukaryotes, including humans. Although the chimeric fusion protein SETMAR is no longer active as a transposase, it contains both the DNA-binding domain (DBD) and catalytic domain of the Hsmar1 transposase. The amino-acid sequence of the DBD has been virtually unchanged in 50 million years and, as a consequence, SETMAR retains its sequence-specific binding to the ancestral Hsmar1 terminal inverted repeat (TIR) sequence. Thus, the DNA-binding activity of SETMAR is likely to have an important biological function. To determine the structural basis for the recognition of TIR DNA by SETMAR, the design of TIR-containing oligonucleotides and SETMAR DBD variants, crystallization of DBD-DNA complexes, phasing strategies and initial phasing experiments are reported here. An unexpected finding was that oligonucleotides containing two BrdUs in place of thymidines produced better quality crystals in complex with SETMAR than their natural counterparts.
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Affiliation(s)
- Qiujia Chen
- Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA
| | - Millie Georgiadis
- Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA
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End-processing nucleases and phosphodiesterases: An elite supporting cast for the non-homologous end joining pathway of DNA double-strand break repair. DNA Repair (Amst) 2016; 43:57-68. [PMID: 27262532 DOI: 10.1016/j.dnarep.2016.05.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 05/05/2016] [Indexed: 11/20/2022]
Abstract
Nonhomologous end joining (NHEJ) is an error-prone DNA double-strand break repair pathway that is active throughout the cell cycle. A substantial fraction of NHEJ repair events show deletions and, less often, insertions in the repair joints, suggesting an end-processing step comprising the removal of mismatched or damaged nucleotides by nucleases and other phosphodiesterases, as well as subsequent strand extension by polymerases. A wide range of nucleases, including Artemis, Metnase, APLF, Mre11, CtIP, APE1, APE2 and WRN, are biochemically competent to carry out such double-strand break end processing, and have been implicated in NHEJ by at least circumstantial evidence. Several additional DNA end-specific phosphodiesterases, including TDP1, TDP2 and aprataxin are available to resolve various non-nucleotide moieties at DSB ends. This review summarizes the biochemical specificities of these enzymes and the evidence for their participation in the NHEJ pathway.
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Wu Y, Lee SH, Williamson EA, Reinert BL, Cho JH, Xia F, Jaiswal AS, Srinivasan G, Patel B, Brantley A, Zhou D, Shao L, Pathak R, Hauer-Jensen M, Singh S, Kong K, Wu X, Kim HS, Beissbarth T, Gaedcke J, Burma S, Nickoloff JA, Hromas RA. EEPD1 Rescues Stressed Replication Forks and Maintains Genome Stability by Promoting End Resection and Homologous Recombination Repair. PLoS Genet 2015; 11:e1005675. [PMID: 26684013 PMCID: PMC4684289 DOI: 10.1371/journal.pgen.1005675] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 10/26/2015] [Indexed: 12/13/2022] Open
Abstract
Replication fork stalling and collapse is a major source of genome instability leading to neoplastic transformation or cell death. Such stressed replication forks can be conservatively repaired and restarted using homologous recombination (HR) or non-conservatively repaired using micro-homology mediated end joining (MMEJ). HR repair of stressed forks is initiated by 5’ end resection near the fork junction, which permits 3’ single strand invasion of a homologous template for fork restart. This 5’ end resection also prevents classical non-homologous end-joining (cNHEJ), a competing pathway for DNA double-strand break (DSB) repair. Unopposed NHEJ can cause genome instability during replication stress by abnormally fusing free double strand ends that occur as unstable replication fork repair intermediates. We show here that the previously uncharacterized Exonuclease/Endonuclease/Phosphatase Domain-1 (EEPD1) protein is required for initiating repair and restart of stalled forks. EEPD1 is recruited to stalled forks, enhances 5’ DNA end resection, and promotes restart of stalled forks. Interestingly, EEPD1 directs DSB repair away from cNHEJ, and also away from MMEJ, which requires limited end resection for initiation. EEPD1 is also required for proper ATR and CHK1 phosphorylation, and formation of gamma-H2AX, RAD51 and phospho-RPA32 foci. Consistent with a direct role in stalled replication fork cleavage, EEPD1 is a 5’ overhang nuclease in an obligate complex with the end resection nuclease Exo1 and BLM. EEPD1 depletion causes nuclear and cytogenetic defects, which are made worse by replication stress. Depleting 53BP1, which slows cNHEJ, fully rescues the nuclear and cytogenetic abnormalities seen with EEPD1 depletion. These data demonstrate that genome stability during replication stress is maintained by EEPD1, which initiates HR and inhibits cNHEJ and MMEJ. The cell itself damages its own DNA throughout the cell cycle as a result of oxidative metabolism, and this damage creates barriers for replication fork progression. Thus, DNA replication is not a smooth and continuous process, but rather one of stalls and restarts. Therefore, proper replication fork restart is crucial to maintain the integrity of the cell’s genome, and preventing its own death or immortalization. To restart after stalling, the replication fork subverts a DNA repair pathway termed homologous recombination. Using any other pathway for fork repair will result in an unstable genome. How the homologous recombination repair pathway is initiated at the replication fork is not well defined. In this study we demonstrate the previously uncharacterized EEPD1 protein is a novel gatekeeper for the initiation of this fork repair pathway. EEPD1 promotes 5’ end resection, the initial step of homologous recombination, which also prevents alternative fork repair pathways that lead to unstable chromosomes. Thus, EEPD1 protects the integrity of the cell genome by promoting the safe homologous recombination fork repair pathway.
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Affiliation(s)
- Yuehan Wu
- Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida, United States of America
| | - Suk-Hee Lee
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Elizabeth A. Williamson
- Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida, United States of America
| | - Brian L. Reinert
- Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida, United States of America
| | - Ju Hwan Cho
- Department of Radiation Oncology, Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, United States of America
| | - Fen Xia
- Department of Radiation Oncology, Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, United States of America
| | - Aruna Shanker Jaiswal
- Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida, United States of America
| | - Gayathri Srinivasan
- Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida, United States of America
| | - Bhavita Patel
- Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida, United States of America
| | - Alexis Brantley
- Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida, United States of America
| | - Daohong Zhou
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Lijian Shao
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Rupak Pathak
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Martin Hauer-Jensen
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Sudha Singh
- Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida, United States of America
| | - Kimi Kong
- Department of Craniofacial Regeneration, College of Dental Medicine, Columbia University, New York, New York, United States of America
| | - Xaiohua Wu
- Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California, United States of America
| | - Hyun-Suk Kim
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Timothy Beissbarth
- Department of Medical Statistics, and General, Visceral, and Pediatric Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Jochen Gaedcke
- Department of Medical Statistics, and General, Visceral, and Pediatric Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Sandeep Burma
- Department of Radiation Oncology, University of Texas Southwestern, Dallas, Texas, United States of America
| | - Jac A. Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail: (JAN); (RAH)
| | - Robert A. Hromas
- Department of Medicine and the Cancer Center, University of Florida Health, Gainesville, Florida, United States of America
- * E-mail: (JAN); (RAH)
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Kim HS, Kim SK, Hromas R, Lee SH. The SET Domain Is Essential for Metnase Functions in Replication Restart and the 5' End of SS-Overhang Cleavage. PLoS One 2015; 10:e0139418. [PMID: 26437079 PMCID: PMC4593633 DOI: 10.1371/journal.pone.0139418] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 09/14/2015] [Indexed: 11/19/2022] Open
Abstract
Metnase (also known as SETMAR) is a chimeric SET-transposase protein that plays essential role(s) in non-homologous end joining (NHEJ) repair and replication fork restart. Although the SET domain possesses histone H3 lysine 36 dimethylation (H3K36me2) activity associated with an improved association of early repair components for NHEJ, its role in replication restart is less clear. Here we show that the SET domain is necessary for the recovery from DNA damage at the replication forks following hydroxyurea (HU) treatment. Cells overexpressing the SET deletion mutant caused a delay in fork restart after HU release. Our In vitro study revealed that the SET domain but not the H3K36me2 activity is required for the 5’ end of ss-overhang cleavage with fork and non-fork DNA without affecting the Metnase-DNA interaction. Together, our results suggest that the Metnase SET domain has a positive role in restart of replication fork and the 5’ end of ss-overhang cleavage, providing a new insight into the functional interaction of the SET and the transposase domains.
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Affiliation(s)
- Hyun-Suk Kim
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Sung-Kyung Kim
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Robert Hromas
- Department of Medicine, University of Florida and Shands Health Care System, Gainesville, Florida, United States of America
| | - Suk-Hee Lee
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- Indiana University Simon Cancer Center, Indianapolis, Indiana, United States of America
- * E-mail:
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28
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Apostolou P, Toloudi M, Kourtidou E, Mimikakou G, Vlachou I, Chatziioannou M, Kipourou V, Papasotiriou I. Potential role for the Metnase transposase fusion gene in colon cancer through the regulation of key genes. PLoS One 2014; 9:e109741. [PMID: 25333365 PMCID: PMC4198141 DOI: 10.1371/journal.pone.0109741] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 09/08/2014] [Indexed: 01/06/2023] Open
Abstract
The Metnase fusion gene consists of a SET histone methyltransferase domain and a transposase domain from Mariner transposase. This transposable element is involved in chromosome decatenation, enhances DNA repair, promotes foreign DNA integration, and assists topoisomerase II function. This study investigates the role of Metnase in colon cancer homeostasis and maintenance of the stemness phenotype in colon cancer stem cells (CSCs). Silencing of Metnase was performed in human cancer cell lines before and after treatment with cisplatin, and in colon CSCs. Subsequent changes in the expression of genes involved in repair mechanisms, DNA synthesis, topoisomerase II function, and metastasis as well stemness transcription factors were studied with RT-qPCR experiments. Cellular viability and apoptosis were evaluated by flow cytometry. The results suggest that Metnase influences the expression of many genes involved in the above processes. Furthermore, Metnase levels appear to impact upon expression of NANOG, OCT3/4, and SOX2. Suppression of Metnase also led to an increase in apoptosis. Therefore, Metnase may possess an important role in DNA repair, topoisomerase II function, and the maintenance of stemness during colon cancer development.
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Affiliation(s)
| | - Maria Toloudi
- Research Genetic Cancer Centre Ltd (R.G.C.C. Ltd), Filotas, Florina, Greece
| | - Eleni Kourtidou
- Research Genetic Cancer Centre Ltd (R.G.C.C. Ltd), Filotas, Florina, Greece
| | - Georgia Mimikakou
- Research Genetic Cancer Centre Ltd (R.G.C.C. Ltd), Filotas, Florina, Greece
| | - Ioanna Vlachou
- Research Genetic Cancer Centre Ltd (R.G.C.C. Ltd), Filotas, Florina, Greece
| | | | - Vasiliki Kipourou
- Research Genetic Cancer Centre Ltd (R.G.C.C. Ltd), Filotas, Florina, Greece
| | - Ioannis Papasotiriou
- Research Genetic Cancer Centre Ltd (R.G.C.C. Ltd), Filotas, Florina, Greece
- * E-mail:
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29
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Williamson EA, Wu Y, Singh S, Byrne M, Wray J, Lee SH, Nickoloff JA, Hromas R. The DNA repair component Metnase regulates Chk1 stability. Cell Div 2014; 9:1. [PMID: 25024738 PMCID: PMC4094783 DOI: 10.1186/1747-1028-9-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 06/09/2014] [Indexed: 12/31/2022] Open
Abstract
Chk1 both arrests replication forks and enhances repair of DNA damage by phosphorylation of downstream effectors. Metnase (also termed SETMAR) is a SET histone methylase and transposase nuclease protein that promotes both DNA double strand break (DSB) repair and re-start of stalled replication forks. We previously found that Chk1 phosphorylation of Metnase on S495 enhanced its DNA DSB repair activity but decreased its ability to re-start stalled replication forks. Here we show that phosphorylated Metnase feeds back to increase the half-life of Chk1. Chk1 half-life is regulated by DDB1 targeting it to Cul4A for ubiquitination and destruction. Metnase decreases Chk1 interaction with DDB1, and decreases Chk1 ubiquitination. These data define a novel pathway for Chk1 regulation, whereby a target of Chk1, Metnase, feeds back to amplify Chk1 stability, and therefore enhance replication fork arrest.
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Affiliation(s)
- Elizabeth A Williamson
- Department of Medicine, University of Florida College of Medicine, 1600 Archer Rd SW, Gainesville, FL 32610, USA
| | - Yuehan Wu
- Department of Medicine, University of Florida College of Medicine, 1600 Archer Rd SW, Gainesville, FL 32610, USA
| | - Sudha Singh
- Department of Medicine, University of Florida College of Medicine, 1600 Archer Rd SW, Gainesville, FL 32610, USA
| | - Michael Byrne
- Department of Medicine, University of Florida College of Medicine, 1600 Archer Rd SW, Gainesville, FL 32610, USA
| | - Justin Wray
- Department of Medicine, University of Florida College of Medicine, 1600 Archer Rd SW, Gainesville, FL 32610, USA
| | - Suk-Hee Lee
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Robert Hromas
- Department of Medicine, University of Florida College of Medicine, 1600 Archer Rd SW, Gainesville, FL 32610, USA
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