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Eckert KA. Nontraditional Roles of DNA Polymerase Eta Support Genome Duplication and Stability. Genes (Basel) 2023; 14:genes14010175. [PMID: 36672916 PMCID: PMC9858799 DOI: 10.3390/genes14010175] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/03/2023] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
DNA polymerase eta (Pol η) is a Y-family polymerase and the product of the POLH gene. Autosomal recessive inheritance of POLH mutations is the cause of the xeroderma pigmentosum variant, a cancer predisposition syndrome. This review summarizes mounting evidence for expanded Pol η cellular functions in addition to DNA lesion bypass that are critical for maintaining genome stability. In vitro, Pol η displays efficient DNA synthesis through difficult-to-replicate sequences, catalyzes D-loop extensions, and utilizes RNA-DNA hybrid templates. Human Pol η is constitutively present at the replication fork. In response to replication stress, Pol η is upregulated at the transcriptional and protein levels, and post-translational modifications regulate its localization to chromatin. Numerous studies show that Pol η is required for efficient common fragile site replication and stability. Additionally, Pol η can be recruited to stalled replication forks through protein-protein interactions, suggesting a broader role in replication fork recovery. During somatic hypermutations, Pol η is recruited by mismatch repair proteins and is essential for VH gene A:T basepair mutagenesis. Within the global context of repeat-dense genomes, the recruitment of Pol η to perform specialized functions during replication could promote genome stability by interrupting pure repeat arrays with base substitutions. Alternatively, not engaging Pol η in genome duplication is costly, as the absence of Pol η leads to incomplete replication and increased chromosomal instability.
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Affiliation(s)
- Kristin A Eckert
- Gittlen Cancer Research Laboratories, Department of Pathology, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17036, USA
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2
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Song K, Minami JK, Huang A, Dehkordi SR, Lomeli SH, Luebeck J, Goodman MH, Moriceau G, Krijgsman O, Dharanipragada P, Ridgley T, Crosson WP, Salazar J, Pazol E, Karin G, Jayaraman R, Balanis NG, Alhani S, Sheu K, Hoeve JT, Palermo A, Motika SE, Senaratne TN, Paraiso KH, Hergenrother PJ, Rao PN, Multani AS, Peeper DS, Bafna V, Lo RS, Graeber TG. Plasticity of Extrachromosomal and Intrachromosomal BRAF Amplifications in Overcoming Targeted Therapy Dosage Challenges. Cancer Discov 2022; 12:1046-1069. [PMID: 34930786 PMCID: PMC9192483 DOI: 10.1158/2159-8290.cd-20-0936] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 11/06/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022]
Abstract
Focal amplifications (FA) can mediate targeted therapy resistance in cancer. Understanding the structure and dynamics of FAs is critical for designing treatments that overcome plasticity-mediated resistance. We developed a melanoma model of dual MAPK inhibitor (MAPKi) resistance that bears BRAFV600 amplifications through either extrachromosomal DNA (ecDNA)/double minutes (DM) or intrachromosomal homogenously staining regions (HSR). Cells harboring BRAFV600E FAs displayed mode switching between DMs and HSRs, from both de novo genetic changes and selection of preexisting subpopulations. Plasticity is not exclusive to ecDNAs, as cells harboring HSRs exhibit drug addiction-driven structural loss of BRAF amplicons upon dose reduction. FA mechanisms can couple with kinase domain duplications and alternative splicing to enhance resistance. Drug-responsive amplicon plasticity is observed in the clinic and can involve other MAPK pathway genes, such as RAF1 and NRAS. BRAF FA-mediated dual MAPKi-resistant cells are more sensitive to proferroptotic drugs, extending the spectrum of ferroptosis sensitivity in MAPKi resistance beyond cases of dedifferentiation. SIGNIFICANCE Understanding the structure and dynamics of oncogene amplifications is critical for overcoming tumor relapse. BRAF amplifications are highly plastic under MAPKi dosage challenges in melanoma, through involvement of de novo genomic alterations, even in the HSR mode. Moreover, BRAF FA-driven, dual MAPKi-resistant cells extend the spectrum of resistance-linked ferroptosis sensitivity. This article is highlighted in the In This Issue feature, p. 873.
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Affiliation(s)
- Kai Song
- Department of Bioengineering, UCLA, Los Angeles, CA 90095, USA
| | - Jenna K. Minami
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
- Department of Integrative Biology and Physiology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Arthur Huang
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Siavash R. Dehkordi
- Department of Computer Science and Engineering, University of California at San Diego, La Jolla, CA 92093, USA
| | - Shirley H. Lomeli
- Division of Dermatology, Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Jens Luebeck
- Department of Computer Science and Engineering, University of California at San Diego, La Jolla, CA 92093, USA
| | - Mark H. Goodman
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Gatien Moriceau
- Division of Dermatology, Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Oscar Krijgsman
- Division of Molecular Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Prashanthi Dharanipragada
- Division of Dermatology, Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Trevor Ridgley
- Bioinformatics Interdepartmental Program, UCLA, Los Angeles, CA, 90095, USA
| | - William P. Crosson
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Jesus Salazar
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Eli Pazol
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Gabriel Karin
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Rachana Jayaraman
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Nikolas G. Balanis
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Salwan Alhani
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Kyle Sheu
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Johanna ten Hoeve
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
- UCLA Metabolomics Center, Los Angeles, CA, 90095, USA
| | - Amelia Palermo
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
- UCLA Metabolomics Center, Los Angeles, CA, 90095, USA
| | - Stephen E. Motika
- Department of Chemistry, Institute for Genomic Biology, Cancer Center at Illinois, University of Illinois, Urbana-Champaign, USA
| | - T. Niroshi Senaratne
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Kim H. Paraiso
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Paul J. Hergenrother
- Department of Chemistry, Institute for Genomic Biology, Cancer Center at Illinois, University of Illinois, Urbana-Champaign, USA
| | - P. Nagesh Rao
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Asha S. Multani
- Department of Genetics, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030
| | - Daniel S. Peeper
- Division of Molecular Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | - Vineet Bafna
- Department of Computer Science and Engineering, University of California at San Diego, La Jolla, CA 92093, USA
| | - Roger S. Lo
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
- Division of Dermatology, Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
- Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA 90095, USA
| | - Thomas G. Graeber
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
- Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA 90095, USA
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA 90095, USA
- California NanoSystems Institute, UCLA, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, UCLA, Los Angeles, CA 90095, USA
- UCLA Metabolomics Center, Los Angeles, CA, 90095, USA
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Quantitative assessment reveals the dominance of duplicated sequences in germline-derived extrachromosomal circular DNA. Proc Natl Acad Sci U S A 2021; 118:2102842118. [PMID: 34789574 PMCID: PMC8617514 DOI: 10.1073/pnas.2102842118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2021] [Indexed: 01/08/2023] Open
Abstract
Extrachromosomal circular DNA (eccDNA) plays a role in human diseases such as cancer, but little is known about the impact of eccDNA in healthy human biology. Since eccDNA is a tiny fraction of nuclear DNA, artificial amplification has been employed to increase eccDNA amounts, resulting in the loss of native compositions. We developed an approach to enrich eccDNA populations at the native state (naïve small circular DNA, nscDNA) and investigated their origins in the human genome. We found that, in human sperm, the vast majority of nscDNA came from high-copy genomic regions, including the most variable regions between individuals. Because eccDNA can be incorporated back into chromosomes, eccDNA may promote human genetic variation. Extrachromosomal circular DNA (eccDNA) originates from linear chromosomal DNA in various human tissues under physiological and disease conditions. The genomic origins of eccDNA have largely been investigated using in vitro–amplified DNA. However, in vitro amplification obscures quantitative information by skewing the total population stoichiometry. In addition, the analyses have focused on eccDNA stemming from single-copy genomic regions, leaving eccDNA from multicopy regions unexamined. To address these issues, we isolated eccDNA without in vitro amplification (naïve small circular DNA, nscDNA) and assessed the populations quantitatively by integrated genomic, molecular, and cytogenetic approaches. nscDNA of up to tens of kilobases were successfully enriched by our approach and were predominantly derived from multicopy genomic regions including segmental duplications (SDs). SDs, which account for 5% of the human genome and are hotspots for copy number variations, were significantly overrepresented in sperm nscDNA, with three times more sequencing reads derived from SDs than from the entire single-copy regions. SDs were also overrepresented in mouse sperm nscDNA, which we estimated to comprise 0.2% of nuclear DNA. Considering that eccDNA can be integrated into chromosomes, germline-derived nscDNA may be a mediator of genome diversity.
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Mognato M, Burdak-Rothkamm S, Rothkamm K. Interplay between DNA replication stress, chromatin dynamics and DNA-damage response for the maintenance of genome stability. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2020; 787:108346. [PMID: 34083038 DOI: 10.1016/j.mrrev.2020.108346] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/02/2020] [Accepted: 11/09/2020] [Indexed: 12/17/2022]
Abstract
DNA replication stress is a major source of DNA damage, including double-stranded breaks that promote DNA damage response (DDR) signaling. Inefficient repair of such lesions can affect genome integrity. During DNA replication different factors act on chromatin remodeling in a coordinated way. While recent studies have highlighted individual molecular mechanisms of interaction, less is known about the orchestration of chromatin changes under replication stress. In this review we attempt to explore the complex relationship between DNA replication stress, DDR and genome integrity in mammalian cells, taking into account the role of chromatin disposition as an important modulator of DNA repair. Recent data on chromatin restoration and epigenetic re-establishment after DNA replication stress are reviewed.
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Affiliation(s)
| | - Susanne Burdak-Rothkamm
- University Medical Center Hamburg-Eppendorf, Department of Radiotherapy, Laboratory of Radiobiology & Experimental Radiation Oncology, Germany.
| | - Kai Rothkamm
- University Medical Center Hamburg-Eppendorf, Department of Radiotherapy, Laboratory of Radiobiology & Experimental Radiation Oncology, Germany.
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5
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Mansilla SF, De La Vega MB, Calzetta NL, Siri SO, Gottifredi V. CDK-Independent and PCNA-Dependent Functions of p21 in DNA Replication. Genes (Basel) 2020; 11:genes11060593. [PMID: 32481484 PMCID: PMC7349641 DOI: 10.3390/genes11060593] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/13/2020] [Accepted: 05/15/2020] [Indexed: 12/12/2022] Open
Abstract
p21Waf/CIP1 is a small unstructured protein that binds and inactivates cyclin-dependent kinases (CDKs). To this end, p21 levels increase following the activation of the p53 tumor suppressor. CDK inhibition by p21 triggers cell-cycle arrest in the G1 and G2 phases of the cell cycle. In the absence of exogenous insults causing replication stress, only residual p21 levels are prevalent that are insufficient to inhibit CDKs. However, research from different laboratories has demonstrated that these residual p21 levels in the S phase control DNA replication speed and origin firing to preserve genomic stability. Such an S-phase function of p21 depends fully on its ability to displace partners from chromatin-bound proliferating cell nuclear antigen (PCNA). Vice versa, PCNA also regulates p21 by preventing its upregulation in the S phase, even in the context of robust p21 induction by irradiation. Such a tight regulation of p21 in the S phase unveils the potential that CDK-independent functions of p21 may have for the improvement of cancer treatments.
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Tanaka H, Watanabe T. Mechanisms Underlying Recurrent Genomic Amplification in Human Cancers. Trends Cancer 2020; 6:462-477. [PMID: 32383436 DOI: 10.1016/j.trecan.2020.02.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 02/20/2020] [Accepted: 02/24/2020] [Indexed: 12/17/2022]
Abstract
Focal copy-number increases (genomic amplification) pinpoint oncogenic driver genes and therapeutic targets in cancer genomes. With the advent of genomic technologies, recurrent genomic amplification has been mapped throughout the genome. Recurrent amplification could be solely due to positive selection for the tumor-promoting effects of amplified gene products. Alternatively, recurrence could result from the susceptibility of the loci to amplification. Distinguishing between these possibilities requires a full understanding of the amplification mechanisms. Two mechanisms, the formation of double minute (DM) chromosomes and breakage-fusion-bridge (BFB) cycles, have been repeatedly linked to genomic amplification, and the impact of both mechanisms has been confirmed in cancer genomics data. We review the details of these mechanisms and discuss the mechanisms underlying recurrence.
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Affiliation(s)
- Hisashi Tanaka
- Department of Surgery, Cedars-Sinai Medical Center, West Hollywood, CA 90046, USA; Biomedical Sciences, Cedars-Sinai Medical Center, West Hollywood, CA 90046, USA; Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, West Hollywood, CA 90046, USA.
| | - Takaaki Watanabe
- Department of Surgery, Cedars-Sinai Medical Center, West Hollywood, CA 90046, USA; Molecular Life Science, Tokai University School of Medicine, Kanagawa, Japan
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7
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Jamal M, Song T, Chen B, Faisal M, Hong Z, Xie T, Wu Y, Pan S, Yin Q, Shao L, Zhang Q. Recent Progress on Circular RNA Research in Acute Myeloid Leukemia. Front Oncol 2019; 9:1108. [PMID: 31781482 PMCID: PMC6851197 DOI: 10.3389/fonc.2019.01108] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 10/07/2019] [Indexed: 12/26/2022] Open
Abstract
Acute myeloid leukemia (AML) is a myeloid malignancy characterized by the proliferation of abnormal and immature myeloid blasts in the bone marrow. Circular RNA (circRNA) is a novel class of long non-coding RNA with a stable circular conformation that regulates various biological processes. The aberrant expression of circRNA and its impact on AML progression has been reported by a number of studies. Despite recent advances in circRNA research, our understanding of the leukemogenic mechanism of circRNA remains very limited, and translating the current circRNA-related research into clinical practice is challenging. This review provides an update on the functional roles of and research progress on circRNAs in AML with an emphasis on mechanistic insights. The challenges and opportunities associated with circRNA-based diagonostic and therapeutic development in AML are also outlined.
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Affiliation(s)
- Muhammad Jamal
- Department of Immunology, School of Basic Medical Science, Wuhan University, Wuhan, China
| | - Tianbao Song
- Department of Immunology, School of Basic Medical Science, Wuhan University, Wuhan, China
| | - Bei Chen
- Department of Immunology, School of Basic Medical Science, Wuhan University, Wuhan, China
| | - Muhammad Faisal
- Institute of Pathology, Hannover Medical School, Hanover, Germany
| | - Zixi Hong
- Department of Immunology, School of Basic Medical Science, Wuhan University, Wuhan, China
| | - Tian Xie
- Department of Immunology, School of Basic Medical Science, Wuhan University, Wuhan, China
| | - Yingjie Wu
- Department of Immunology, School of Basic Medical Science, Wuhan University, Wuhan, China
| | - Shan Pan
- Department of Immunology, School of Basic Medical Science, Wuhan University, Wuhan, China
| | - Qian Yin
- Department of Immunology, School of Basic Medical Science, Wuhan University, Wuhan, China
| | - Liang Shao
- Department of Hematology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Qiuping Zhang
- Department of Immunology, School of Basic Medical Science, Wuhan University, Wuhan, China.,Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan University, Wuhan, China
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8
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Saha A, Nanavaty VP, Li B. Telomere and Subtelomere R-loops and Antigenic Variation in Trypanosomes. J Mol Biol 2019; 432:4167-4185. [PMID: 31682833 DOI: 10.1016/j.jmb.2019.10.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 10/02/2019] [Accepted: 10/21/2019] [Indexed: 12/12/2022]
Abstract
Trypanosoma brucei is a kinetoplastid parasite that causes African trypanosomiasis, which is fatal if left untreated. T. brucei regularly switches its major surface antigen, VSG, to evade the host immune responses. VSGs are exclusively expressed from subtelomeric expression sites (ESs) where VSG genes are flanked by upstream 70 bp repeats and downstream telomeric repeats. The telomere downstream of the active VSG is transcribed into a long-noncoding RNA (TERRA), which forms RNA:DNA hybrids (R-loops) with the telomeric DNA. At an elevated level, telomere R-loops cause more telomeric and subtelomeric double-strand breaks (DSBs) and increase VSG switching rate. In addition, stabilized R-loops are observed at the 70 bp repeats and immediately downstream of ES-linked VSGs in RNase H defective cells, which also have an increased amount of subtelomeric DSBs and more frequent VSG switching. Although subtelomere plasticity is expected to be beneficial to antigenic variation, severe defects in subtelomere integrity and stability increase cell lethality. Therefore, regulation of the telomere and 70 bp repeat R-loop levels is important for the balance between antigenic variation and cell fitness in T. brucei. In addition, the high level of the active ES transcription favors accumulation of R-loops at the telomere and 70 bp repeats, providing an intrinsic mechanism for local DSB formation, which is a strong inducer of VSG switching.
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Affiliation(s)
- Arpita Saha
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Science and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Vishal P Nanavaty
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Science and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Science and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA; Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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9
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Damasceno JD, Obonaga R, Silva GLA, Reis-Cunha JL, Duncan SM, Bartholomeu DC, Mottram JC, McCulloch R, Tosi LRO. Conditional genome engineering reveals canonical and divergent roles for the Hus1 component of the 9-1-1 complex in the maintenance of the plastic genome of Leishmania. Nucleic Acids Res 2019; 46:11835-11846. [PMID: 30380080 PMCID: PMC6294564 DOI: 10.1093/nar/gky1017] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 10/11/2018] [Indexed: 12/16/2022] Open
Abstract
Leishmania species are protozoan parasites whose remarkably plastic genome limits the establishment of effective genetic manipulation and leishmaniasis treatment. The strategies used by Leishmania to maintain its genome while allowing variability are not fully understood. Here, we used DiCre-mediated conditional gene deletion to show that HUS1, a component of the 9-1-1 (RAD9-RAD1-HUS1) complex, is essential and is required for a G2/M checkpoint. By analyzing genome-wide instability in HUS1 ablated cells, HUS1 is shown to have a conserved role, by which it preserves genome stability and also a divergent role, by which it promotes genome variability. These roles of HUS1 are related to distinct patterns of formation and resolution of single-stranded DNA and γH2A, throughout the cell cycle. Our findings suggest that Leishmania 9-1-1 subunits have evolved to co-opt canonical genomic maintenance and genomic variation functions. Hence, this study reveals a pivotal function of HUS1 in balancing genome stability and transmission in Leishmania. These findings may be relevant to understanding the evolution of genome maintenance and plasticity in other pathogens and eukaryotes.
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Affiliation(s)
- Jeziel D Damasceno
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
| | - Ricardo Obonaga
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
| | - Gabriel L A Silva
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
| | - João L Reis-Cunha
- Laboratório de Genômica de Parasitos, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brasil
| | - Samuel M Duncan
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8TA, UK
| | - Daniella C Bartholomeu
- Laboratório de Genômica de Parasitos, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brasil
| | - Jeremy C Mottram
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8TA, UK.,Centre for Immunology and Infection, Department of Biology, University of York, York YO10 5DD, UK
| | - Richard McCulloch
- Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8TA, UK
| | - Luiz R O Tosi
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
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Abstract
Flaws in the DNA replication process have emerged as a leading driver of genome instability in human diseases. Alteration to replication fork progression is a defining feature of replication stress and the consequent failure to maintain fork integrity and complete genome duplication within a single round of S-phase compromises genetic integrity. This includes increased mutation rates, small and large scale genomic rearrangement and deleterious consequences for the subsequent mitosis that result in the transmission of additional DNA damage to the daughter cells. Therefore, preserving fork integrity and replication competence is an important aspect of how cells respond to replication stress and avoid genetic change. Homologous recombination is a pivotal pathway in the maintenance of genome integrity in the face of replication stress. Here we review our recent understanding of the mechanisms by which homologous recombination acts to protect, restart and repair replication forks. We discuss the dynamics of these genetically distinct functions and their contribution to faithful mitoticsegregation.
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11
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Affiliation(s)
- Nicholas Manguso
- Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Armando E Giuliano
- Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Hisashi Tanaka
- Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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12
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Yang Y, Gao Y, Zlatanou A, Tateishi S, Yurchenko V, Rogozin IB, Vaziri C. Diverse roles of RAD18 and Y-family DNA polymerases in tumorigenesis. Cell Cycle 2018; 17:833-843. [PMID: 29683380 PMCID: PMC6056224 DOI: 10.1080/15384101.2018.1456296] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Mutagenesis is a hallmark and enabling characteristic of cancer cells. The E3 ubiquitin ligase RAD18 and its downstream effectors, the ‘Y-family’ Trans-Lesion Synthesis (TLS) DNA polymerases, confer DNA damage tolerance at the expense of DNA replication fidelity. Thus, RAD18 and TLS polymerases are attractive candidate mediators of mutagenesis and carcinogenesis. The skin cancer-propensity disorder xeroderma pigmentosum-variant (XPV) is caused by defects in the Y-family DNA polymerase Pol eta (Polη). However it is unknown whether TLS dysfunction contributes more generally to other human cancers. Recent analyses of cancer genomes suggest that TLS polymerases generate many of the mutational signatures present in diverse cancers. Moreover biochemical studies suggest that the TLS pathway is often reprogrammed in cancer cells and that TLS facilitates tolerance of oncogene-induced DNA damage. Here we review recent evidence supporting widespread participation of RAD18 and the Y-family DNA polymerases in the different phases of multi-step carcinogenesis.
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Affiliation(s)
- Yang Yang
- a Department of Pathology and Laboratory Medicine , University of North Carolina at Chapel Hill Chapel Hill , NC , USA
| | - Yanzhe Gao
- a Department of Pathology and Laboratory Medicine , University of North Carolina at Chapel Hill Chapel Hill , NC , USA
| | - Anastasia Zlatanou
- a Department of Pathology and Laboratory Medicine , University of North Carolina at Chapel Hill Chapel Hill , NC , USA
| | - Satoshi Tateishi
- b Division of Cell Maintenance , Institute of Molecular Embryology and Genetics (IMEG) , Kumamoto University , Kumamoto , Japan
| | - Vyacheslav Yurchenko
- c Life Science Research Center , University of Ostrava , Ostrava , Czech Republic
| | - Igor B Rogozin
- d National Center for Biotechnology Information, National Library of Medicine , National Institutes of Health , Bethesda , MD , USA
| | - Cyrus Vaziri
- a Department of Pathology and Laboratory Medicine , University of North Carolina at Chapel Hill Chapel Hill , NC , USA
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