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Atasu B, Simón-Sánchez J, Hanagasi H, Bilgic B, Hauser AK, Guven G, Heutink P, Gasser T, Lohmann E. Dissecting genetic architecture of rare dystonia: genetic, molecular and clinical insights. J Med Genet 2024; 61:443-451. [PMID: 38458754 DOI: 10.1136/jmg-2022-109099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 12/24/2023] [Indexed: 03/10/2024]
Abstract
BACKGROUND Dystonia is one of the most common movement disorders. To date, the genetic causes of dystonia in populations of European descent have been extensively studied. However, other populations, particularly those from the Middle East, have not been adequately studied. The purpose of this study is to discover the genetic basis of dystonia in a clinically and genetically well-characterised dystonia cohort from Turkey, which harbours poorly studied populations. METHODS Exome sequencing analysis was performed in 42 Turkish dystonia families. Using co-expression network (CEN) analysis, identified candidate genes were interrogated for the networks including known dystonia-associated genes and genes further associated with the protein-protein interaction, animal model-based characteristics and clinical findings. RESULTS We identified potentially disease-causing variants in the established dystonia genes (PRKRA, SGCE, KMT2B, SLC2A1, GCH1, THAP1, HPCA, TSPOAP1, AOPEP; n=11 families (26%)), in the uncommon forms of dystonia-associated genes (PCCB, CACNA1A, ALDH5A1, PRKN; n=4 families (10%)) and in the candidate genes prioritised based on the pathogenicity of the variants and CEN-based analyses (n=11 families (21%)). The diagnostic yield was found to be 36%. Several pathways and gene ontologies implicated in immune system, transcription, metabolic pathways, endosomal-lysosomal and neurodevelopmental mechanisms were over-represented in our CEN analysis. CONCLUSIONS Here, using a structured approach, we have characterised a clinically and genetically well-defined dystonia cohort from Turkey, where dystonia has not been widely studied, and provided an uncovered genetic basis, which will facilitate diagnostic dystonia research.
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Affiliation(s)
- Burcu Atasu
- Eberhard Karls Universität Tübingen Hertie Institut für klinische Hirnforschung Allgemeine Neurologie, Tubingen, Germany
| | - Javier Simón-Sánchez
- Eberhard Karls Universität Tübingen Hertie Institut für klinische Hirnforschung Allgemeine Neurologie, Tubingen, Germany
| | - Hasmet Hanagasi
- Department of Neurology, Istanbul University Istanbul Faculty of Medicine, Istanbul, Turkey
| | - Basar Bilgic
- Department of Neurology, Istanbul University Istanbul Faculty of Medicine, Istanbul, Turkey
| | - Ann-Kathrin Hauser
- Eberhard Karls Universität Tübingen Hertie Institut für klinische Hirnforschung Allgemeine Neurologie, Tubingen, Germany
| | - Gamze Guven
- Genetics Department, Aziz Sancar Institute of Experimental Medicine, Istanbul, Turkey
| | | | - Thomas Gasser
- Eberhard Karls Universität Tübingen Hertie Institut für klinische Hirnforschung Allgemeine Neurologie, Tubingen, Germany
| | - Ebba Lohmann
- Eberhard Karls Universität Tübingen Hertie Institut für klinische Hirnforschung Allgemeine Neurologie, Tubingen, Germany
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2
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Fleifel D, Cook JG. G1 Dynamics at the Crossroads of Pluripotency and Cancer. Cancers (Basel) 2023; 15:4559. [PMID: 37760529 PMCID: PMC10526231 DOI: 10.3390/cancers15184559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 08/29/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
G1 cell cycle phase dynamics are regulated by intricate networks involving cyclins, cyclin-dependent kinases (CDKs), and CDK inhibitors, which control G1 progression and ensure proper cell cycle transitions. Moreover, adequate origin licensing in G1 phase, the first committed step of DNA replication in the subsequent S phase, is essential to maintain genome integrity. In this review, we highlight the intriguing parallels and disparities in G1 dynamics between stem cells and cancer cells, focusing on their regulatory mechanisms and functional outcomes. Notably, SOX2, OCT4, KLF4, and the pluripotency reprogramming facilitator c-MYC, known for their role in establishing and maintaining stem cell pluripotency, are also aberrantly expressed in certain cancer cells. In this review, we discuss recent advances in understanding the regulatory role of these pluripotency factors in G1 dynamics in the context of stem cells and cancer cells, which may offer new insights into the interconnections between pluripotency and tumorigenesis.
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Affiliation(s)
| | - Jeanette Gowen Cook
- Department of Biochemistry & Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
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3
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Kislova AV, Zheglo D, Pozhitnova VO, Sviridov PS, Gadzhieva EP, Voronina ES. Replication stress causes delayed mitotic entry and chromosome 12 fragility at the ANKS1B large neuronal gene in human induced pluripotent stem cells. Chromosome Res 2023; 31:23. [PMID: 37597021 DOI: 10.1007/s10577-023-09729-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 07/10/2023] [Accepted: 07/19/2023] [Indexed: 08/21/2023]
Abstract
Substantial background level of replication stress is a feature of embryonic and induced pluripotent stem cells (iPSCs), which can predispose to numerical and structural chromosomal instability, including recurrent aberrations of chromosome 12. In differentiated cells, replication stress-sensitive genomic regions, including common fragile sites, are widely mapped through mitotic chromosome break induction by mild aphidicolin treatment, an inhibitor of replicative polymerases. IPSCs exhibit lower apoptotic threshold and higher repair capacity hindering fragile site mapping. Caffeine potentiates genotoxic effects and abrogates G2/M checkpoint delay induced by chemical and physical mutagens. Using 5-ethynyl-2'-deoxyuridine (EdU) for replication labeling, we characterized the mitotic entry dynamics of asynchronous iPSCs exposed to aphidicolin and/or caffeine. Under the adjusted timing of replication stress exposure accounting revealed cell cycle delay, higher metaphase chromosome breakage rate was observed in iPSCs compared to primary lymphocytes. Using differential chromosome staining and subsequent locus-specific fluorescent in situ hybridization, we mapped the FRA12L fragile site spanning the large neuronal ANKS1B gene at 12q23.1, which may contribute to recurrent chromosome 12 missegregation and rearrangements in iPSCs. Publicly available data on the ANKS1B genetic alterations and their possible functional impact are reviewed. Our study provides the first evidence of common fragile site induction in iPSCs and reveals potential somatic instability of a clinically relevant gene during early human development and in vitro cell expansion.
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Affiliation(s)
| | - Diana Zheglo
- Laboratory of Mutagenesis, Research Centre for Medical Genetics, Moscow, Russia.
| | | | - Philipp S Sviridov
- Laboratory of Mutagenesis, Research Centre for Medical Genetics, Moscow, Russia
| | - Elmira P Gadzhieva
- Laboratory of Mutagenesis, Research Centre for Medical Genetics, Moscow, Russia
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4
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Tichy ED. Specialized Circuitry of Embryonic Stem Cells Promotes Genomic Integrity. Crit Rev Oncog 2023; 27:1-15. [PMID: 36734869 DOI: 10.1615/critrevoncog.2022042332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Embryonic stem cells (ESCs) give rise to all cell types of the organism. Given the importance of these cells in this process, ESCs must employ robust mechanisms to protect genomic integrity or risk catastrophic propagation of mutations throughout the organism. Should such an event occur in daughter cells that will eventually contribute to the germline, the overall species health could dramatically decline. This review describes several key mechanisms employed by ESCs that are unique to these cells, in order to maintain their genomic integrity. Additionally, the contributions of cell cycle regulators in modulating ESC differentiation, after DNA damage exposure, are also examined. Where data are available, findings reported in ESCs are extended to include observations described in induced pluripotent stem cells (IPSCs).
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Affiliation(s)
- Elisia D Tichy
- Department of Orthopaedic Surgery, Perelman School of Medicine, The University of Pennsylvania, 371 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104-6081
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5
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Zhang W, Tang M, Wang L, Zhou H, Gao J, Chen Z, Zhao B, Zheng P. Lnc956-TRIM28-HSP90B1 complex on replication forks promotes CMG helicase retention to ensure stem cell genomic stability and embryogenesis. SCIENCE ADVANCES 2023; 9:eadf6277. [PMID: 36706191 PMCID: PMC9882984 DOI: 10.1126/sciadv.adf6277] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 12/22/2022] [Indexed: 06/18/2023]
Abstract
Replication stress is a major source of endogenous DNA damage. Despite the identification of numerous proteins on replication forks to modulate fork or replication machinery activities, it remains unexplored whether noncoding RNAs can localize on stalled forks and play critical regulatory roles. Here, we identify an uncharacterized long noncoding RNA NONMMUT028956 (Lnc956 for short) predominantly expressed in mouse embryonic stem cells. Lnc956 is accumulated on replication forks to prevent fork collapse and preserve genomic stability and is essential for mouse embryogenesis. Mechanistically, it drives assembly of the Lnc956-TRIM28-HSP90B1 complex on stalled forks in an interdependent manner downstream of ataxia telangiectasia and Rad3-related (ATR) signaling. Lnc956-TRIM28-HSP90B1 complex physically associates with minichromosome maintenance proteins 2 (MCM2) to minichromosome maintenance proteins 7 (MCM7) hexamer via TRIM28 and directly regulates the CDC45-MCM-GINS (CMG) helicase retention on chromatin. The regulation of Lnc956-TRIM28-HSP90B1 on CMG retention is mediated by HSP90B1's chaperoning function. These findings reveal a player that actively regulates replisome retention to prevent fork collapse.
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Affiliation(s)
- Weidao Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Min Tang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Lin Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Hu Zhou
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jing Gao
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Zhongliang Chen
- Key Laboratory of Adult Stem Cell Translational Research (Chinese Academy of Medical Sciences), Guizhou Medical University, Guiyang, China
- National Joint Local Engineering Laboratory for Cell Engineering and Biomedicine Technique, Guizhou Medical University, Guiyang, China
| | - Bo Zhao
- Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Ping Zheng
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
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6
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Ma H, Ning Y, Wang L, Zhang W, Zheng P. Lnc956 regulates mouse embryonic stem cell differentiation in response to DNA damage in a p53-independent pathway. SCIENCE ADVANCES 2023; 9:eade9742. [PMID: 36662856 PMCID: PMC9858519 DOI: 10.1126/sciadv.ade9742] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Maintaining genomic stability is crucial for embryonic stem cells (ESCs). ESCs with unrepaired DNA damage are eliminated through differentiation and apoptosis. To date, only tumor suppressor p53 is known to be implicated in this quality control process. Here, we identified a p53-independent quality control factor lncRNA NONMMUT028956 (Lnc956 for short) in mouse ESCs. Lnc956 is prevalently expressed in ESCs and regulates the differentiation of ESCs after DNA damage. Mechanistically, Ataxia telangiectasia mutated (ATM) activation drives m6A methylation of Lnc956, which promotes its interaction with Krüppel-like factor 4 (KLF4). Lnc956-KLF4 association sequestrates the KLF4 protein and prevents KLF4's transcriptional regulation on pluripotency. This posttranslational mechanism favors the rapid shutdown of the regulatory circuitry of pluripotency. Thus, ATM signaling in ESCs can activate two pathways mediated by p53 and Lnc956, respectively, which act together to ensure robust differentiation and apoptosis in response to unrepaired DNA damage.
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Affiliation(s)
- Huaixiao Ma
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Yuqi Ning
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Lin Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Weidao Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Ping Zheng
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
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7
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Kalogeropoulou A, Mougkogianni M, Iliadou M, Nikolopoulou E, Flordelis S, Kanellou A, Arbi M, Nikou S, Nieminuszczy J, Niedzwiedz W, Kardamakis D, Bravou V, Lygerou Z, Taraviras S. Intrinsic neural stem cell properties define brain hypersensitivity to genotoxic stress. Stem Cell Reports 2022; 17:1395-1410. [PMID: 35623353 PMCID: PMC9214316 DOI: 10.1016/j.stemcr.2022.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 04/28/2022] [Accepted: 04/29/2022] [Indexed: 11/25/2022] Open
Abstract
Impaired replication has been previously linked to growth retardation and microcephaly; however, why the brain is critically affected compared with other organs remains elusive. Here, we report the differential response between early neural progenitors (neuroepithelial cells [NECs]) and fate-committed neural progenitors (NPs) to replication licensing defects. Our results show that, while NPs can tolerate altered expression of licensing factors, NECs undergo excessive replication stress, identified by impaired replication, increased DNA damage, and defective cell-cycle progression, leading eventually to NEC attrition and microcephaly. NECs that possess a short G1 phase license and activate more origins than NPs, by acquiring higher levels of DNA-bound MCMs. In vivo G1 shortening in NPs induces DNA damage upon impaired licensing, suggesting that G1 length correlates with replication stress hypersensitivity. Our findings propose that NECs possess distinct cell-cycle characteristics to ensure fast proliferation, although these inherent features render them susceptible to genotoxic stress.
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Affiliation(s)
- Argyro Kalogeropoulou
- Department of Physiology, School of Medicine, University of Patras, Basic Medical Sciences Building, 1 Asklepiou Str., University Campus, 26504, Rio, Patras, Greece
| | - Maria Mougkogianni
- Department of Physiology, School of Medicine, University of Patras, Basic Medical Sciences Building, 1 Asklepiou Str., University Campus, 26504, Rio, Patras, Greece
| | - Marianna Iliadou
- Department of Physiology, School of Medicine, University of Patras, Basic Medical Sciences Building, 1 Asklepiou Str., University Campus, 26504, Rio, Patras, Greece
| | - Eleni Nikolopoulou
- Department of Physiology, School of Medicine, University of Patras, Basic Medical Sciences Building, 1 Asklepiou Str., University Campus, 26504, Rio, Patras, Greece
| | - Stefanos Flordelis
- Department of Physiology, School of Medicine, University of Patras, Basic Medical Sciences Building, 1 Asklepiou Str., University Campus, 26504, Rio, Patras, Greece
| | - Alexandra Kanellou
- Department of General Biology, School of Medicine, University of Patras, Patras, Greece
| | - Marina Arbi
- Department of General Biology, School of Medicine, University of Patras, Patras, Greece
| | - Sofia Nikou
- Department of Anatomy-Histology-Embryology, School of Medicine, University of Patras, Patras, Greece
| | | | | | - Dimitrios Kardamakis
- Department of Radiation Oncology, School of Medicine, University of Patras, Patras, Greece
| | - Vasiliki Bravou
- Department of Anatomy-Histology-Embryology, School of Medicine, University of Patras, Patras, Greece
| | - Zoi Lygerou
- Department of General Biology, School of Medicine, University of Patras, Patras, Greece
| | - Stavros Taraviras
- Department of Physiology, School of Medicine, University of Patras, Basic Medical Sciences Building, 1 Asklepiou Str., University Campus, 26504, Rio, Patras, Greece.
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8
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Kang X, Yang X, Guo X, Li Y, Yang C, Wei H, Chang J. OUP accepted manuscript. J Mol Cell Biol 2022; 14:6544677. [PMID: 35259279 PMCID: PMC9254884 DOI: 10.1093/jmcb/mjac014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 02/23/2022] [Accepted: 03/04/2022] [Indexed: 11/24/2022] Open
Abstract
Sense mutations in several conserved modifiable sites of histone H3 have been found to be strongly correlated with multiple tissue-specific clinical cancers. These clinical site mutants acquire a distinctively new epigenetic role and mediate cancer evolution. In this study, we mimicked histone H3 at the 56th lysine (H3K56) mutant incorporation in mouse embryonic stem cells (mESCs) by lentivirus-mediated ectopic expression and analyzed the effects on replication and epigenetic regulation. The data show that two types of H3K56 mutants, namely H3 lysine 56-to-methionine (H3K56M) and H3 lysine 56-to-alanine (H3K56A), promote replication by recruiting more minichromosome maintenance complex component 3 and checkpoint kinase 1 onto chromatin compared with wild-type histone H3 and other site substitution mutants. Under this condition, the frequency of genomic copy number gain in H3K56M and H3K56A cells globally increases, especially in the Mycl1 region, a known molecular marker frequently occurring in multiple malignant cancers. Additionally, we found the disruption of H3K56 acetylation distribution in the copy-gain regions, which indicates a probable epigenetic mechanism of H3K56M and H3K56A. We then identified that H3K56M and H3K56A can trigger a potential adaptation to transcription; genes involved in the mitogen-activated protein kinase pathway are partially upregulated, whereas genes associated with intrinsic apoptotic function show obvious downregulation. The final outcome of ectopic H3K56M and H3K56A incorporation in mESCs is an enhanced ability to form carcinomas. This work indicates that H3K56 site conservation and proper modification play important roles in harmonizing the function of the replication machinery in mESCs.
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Affiliation(s)
- Xuan Kang
- Correspondence to: Xuan Kang, E-mail:
| | - Xiaomei Yang
- Research Center for Translational Medicine, East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Xiaobo Guo
- Research Center for Translational Medicine, East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Yabin Li
- Research Center for Translational Medicine, East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Chenxin Yang
- Research Center for Translational Medicine, East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
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9
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Wang L, Li J, Zhou H, Zhang W, Gao J, Zheng P. A novel lncRNA Discn fine-tunes replication protein A (RPA) availability to promote genomic stability. Nat Commun 2021; 12:5572. [PMID: 34552092 PMCID: PMC8458541 DOI: 10.1038/s41467-021-25827-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 08/31/2021] [Indexed: 11/24/2022] Open
Abstract
RPA is a master regulator of DNA metabolism and RPA availability acts as a rate-limiting factor. While numerous studies focused on the post-translational regulations of RPA for its functions, little is known regarding how RPA availability is controlled. Here we identify a novel lncRNA Discn as the guardian of RPA availability in stem cells. Discn is induced upon genotoxic stress and binds to neucleolin (NCL) in the nucleolus. This prevents NCL from translocation into nucleoplasm and avoids undesirable NCL-mediated RPA sequestration. Thus, Discn-NCL-RPA pathway preserves a sufficient RPA pool for DNA replication stress response and repair. Discn loss causes massive genome instability in mouse embryonic stem cells and neural stem/progenigor cells. Mice depleted of Discn display newborn death and brain dysfunctions due to DNA damage accumulation and associated inflammatory reactions. Our findings uncover a key regulator of DNA metabolism and provide new clue to understand the chemoresistance in cancer treatment.
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Affiliation(s)
- Lin Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- Yunnan Key Laboratory of Animal Reproduction, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
| | - Jingzheng Li
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- Yunnan Key Laboratory of Animal Reproduction, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- University of Chinese Academy of Sciences, Beijing, 101408, China
| | - Hu Zhou
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Weidao Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- Yunnan Key Laboratory of Animal Reproduction, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
| | - Jing Gao
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Ping Zheng
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China.
- Yunnan Key Laboratory of Animal Reproduction, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China.
- KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China.
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, 650223, China.
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10
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Munisha M, Schimenti JC. Genome maintenance during embryogenesis. DNA Repair (Amst) 2021; 106:103195. [PMID: 34358805 DOI: 10.1016/j.dnarep.2021.103195] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 12/25/2022]
Abstract
Genome maintenance during embryogenesis is critical, because defects during this period can be perpetuated and thus have a long-term impact on individual's health and longevity. Nevertheless, genome instability is normal during certain aspects of embryonic development, indicating that there is a balance between the exigencies of timely cell proliferation and mutation prevention. In particular, early embryos possess unique cellular and molecular features that underscore the challenge of having an appropriate balance. Here, we discuss genome instability during embryonic development, the mechanisms used in various cell compartments to manage genomic stress and address outstanding questions regarding the balance between genome maintenance mechanisms in key cell types that are important for adulthood and progeny.
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Affiliation(s)
- Mumingjiang Munisha
- Dept. of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, United States
| | - John C Schimenti
- Dept. of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, United States.
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11
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Novo CL. A Tale of Two States: Pluripotency Regulation of Telomeres. Front Cell Dev Biol 2021; 9:703466. [PMID: 34307383 PMCID: PMC8300013 DOI: 10.3389/fcell.2021.703466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/08/2021] [Indexed: 01/01/2023] Open
Abstract
Inside the nucleus, chromatin is functionally organized and maintained as a complex three-dimensional network of structures with different accessibility such as compartments, lamina associated domains, and membraneless bodies. Chromatin is epigenetically and transcriptionally regulated by an intricate and dynamic interplay of molecular processes to ensure genome stability. Phase separation, a process that involves the spontaneous organization of a solution into separate phases, has been proposed as a mechanism for the timely coordination of several cellular processes, including replication, transcription and DNA repair. Telomeres, the repetitive structures at the end of chromosomes, are epigenetically maintained in a repressed heterochromatic state that prevents their recognition as double-strand breaks (DSB), avoiding DNA damage repair and ensuring cell proliferation. In pluripotent embryonic stem cells, telomeres adopt a non-canonical, relaxed epigenetic state, which is characterized by a low density of histone methylation and expression of telomere non-coding transcripts (TERRA). Intriguingly, this telomere non-canonical conformation is usually associated with chromosome instability and aneuploidy in somatic cells, raising the question of how genome stability is maintained in a pluripotent background. In this review, we will explore how emerging technological and conceptual developments in 3D genome architecture can provide novel mechanistic perspectives for the pluripotent epigenetic paradox at telomeres. In particular, as RNA drives the formation of LLPS, we will consider how pluripotency-associated high levels of TERRA could drive and coordinate phase separation of several nuclear processes to ensure genome stability. These conceptual advances will provide a better understanding of telomere regulation and genome stability within the highly dynamic pluripotent background.
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Affiliation(s)
- Clara Lopes Novo
- The Francis Crick Institute, London, United Kingdom
- Imperial College London, London, United Kingdom
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12
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Spotlight on the Replisome: Aetiology of DNA Replication-Associated Genetic Diseases. Trends Genet 2021; 37:317-336. [DOI: 10.1016/j.tig.2020.09.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/07/2020] [Accepted: 09/09/2020] [Indexed: 12/26/2022]
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13
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Atkins A, Xu MJ, Li M, Rogers NP, Pryzhkova MV, Jordan PW. SMC5/6 is required for replication fork stability and faithful chromosome segregation during neurogenesis. eLife 2020; 9:e61171. [PMID: 33200984 PMCID: PMC7723410 DOI: 10.7554/elife.61171] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 11/16/2020] [Indexed: 12/21/2022] Open
Abstract
Mutations of SMC5/6 components cause developmental defects, including primary microcephaly. To model neurodevelopmental defects, we engineered a mouse wherein Smc5 is conditionally knocked out (cKO) in the developing neocortex. Smc5 cKO mice exhibited neurodevelopmental defects due to neural progenitor cell (NPC) apoptosis, which led to reduction in cortical layer neurons. Smc5 cKO NPCs formed DNA bridges during mitosis and underwent chromosome missegregation. SMC5/6 depletion triggers a CHEK2-p53 DNA damage response, as concomitant deletion of the Trp53 tumor suppressor or Chek2 DNA damage checkpoint kinase rescued Smc5 cKO neurodevelopmental defects. Further assessment using Smc5 cKO and auxin-inducible degron systems demonstrated that absence of SMC5/6 leads to DNA replication stress at late-replicating regions such as pericentromeric heterochromatin. In summary, SMC5/6 is important for completion of DNA replication prior to entering mitosis, which ensures accurate chromosome segregation. Thus, SMC5/6 functions are critical in highly proliferative stem cells during organism development.
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Affiliation(s)
- Alisa Atkins
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public HealthBaltimoreUnited States
| | - Michelle J Xu
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public HealthBaltimoreUnited States
| | - Maggie Li
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public HealthBaltimoreUnited States
| | - Nathaniel P Rogers
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public HealthBaltimoreUnited States
| | - Marina V Pryzhkova
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public HealthBaltimoreUnited States
| | - Philip W Jordan
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public HealthBaltimoreUnited States
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14
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Paniza T, Deshpande M, Wang N, O’Neil R, Zuccaro MV, Smith ME, Madireddy A, James D, Ecker J, Rosenwaks Z, Egli D, Gerhardt J. Pluripotent stem cells with low differentiation potential contain incompletely reprogrammed DNA replication. J Cell Biol 2020; 219:e201909163. [PMID: 32673399 PMCID: PMC7480103 DOI: 10.1083/jcb.201909163] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/26/2020] [Accepted: 05/13/2020] [Indexed: 12/20/2022] Open
Abstract
Reprogrammed pluripotent stem cells (PSCs) are valuable for research and potentially for cell replacement therapy. However, only a fraction of reprogrammed PSCs are developmentally competent. Genomic stability and accurate DNA synthesis are fundamental for cell development and critical for safety. We analyzed whether defects in DNA replication contribute to genomic instability and the diverse differentiation potentials of reprogrammed PSCs. Using a unique single-molecule approach, we visualized DNA replication in isogenic PSCs generated by different reprogramming approaches, either somatic cell nuclear transfer (NT-hESCs) or with defined factors (iPSCs). In PSCs with lower differentiation potential, DNA replication was incompletely reprogrammed, and genomic instability increased during replicative stress. Reprogramming of DNA replication did not correlate with DNA methylation. Instead, fewer replication origins and a higher frequency of DNA breaks in PSCs with incompletely reprogrammed DNA replication were found. Given the impact of error-free DNA synthesis on the genomic integrity and differentiation proficiency of PSCs, analyzing DNA replication may be a useful quality control tool.
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Affiliation(s)
- Theodore Paniza
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY
| | - Madhura Deshpande
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY
| | - Ning Wang
- Department of Pediatrics, Columbia University, New York, NY
| | - Ryan O’Neil
- Plant Molecular and Cellular Biology Laboratory, Salk Institute, La Jolla, CA
| | - Michael V. Zuccaro
- Department of Pediatrics, Columbia University, New York, NY
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY
| | | | - Advaitha Madireddy
- Department of Pediatric Hematology/Oncology, Rutgers University, New Brunswick, NJ
| | - Daylon James
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, NY
| | - Joseph Ecker
- Plant Molecular and Cellular Biology Laboratory, Salk Institute, La Jolla, CA
| | - Zev Rosenwaks
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY
| | - Dieter Egli
- Department of Pediatrics, Columbia University, New York, NY
| | - Jeannine Gerhardt
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, NY
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15
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Kafer GR, Cesare AJ. A Survey of Essential Genome Stability Genes Reveals That Replication Stress Mitigation Is Critical for Peri-Implantation Embryogenesis. Front Cell Dev Biol 2020; 8:416. [PMID: 32548123 PMCID: PMC7274024 DOI: 10.3389/fcell.2020.00416] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 05/05/2020] [Indexed: 12/16/2022] Open
Abstract
Murine development demands that pluripotent epiblast stem cells in the peri-implantation embryo increase from approximately 120 to 14,000 cells between embryonic days (E) 4.5 and E7.5. This is possible because epiblast stem cells can complete cell cycles in under 3 h in vivo. To ensure conceptus fitness, epiblast cells must undertake this proliferative feat while maintaining genome integrity. How epiblast cells maintain genome health under such an immense proliferation demand remains unclear. To illuminate the contribution of genome stability pathways to early mammalian development we systematically reviewed knockout mouse data from 347 DDR and repair associated genes. Cumulatively, the data indicate that while many DNA repair functions are dispensable in embryogenesis, genes encoding replication stress response and homology directed repair factors are essential specifically during the peri-implantation stage of early development. We discuss the significance of these findings in the context of the unique proliferative demands placed on pluripotent epiblast stem cells.
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Affiliation(s)
- Georgia R Kafer
- Genome Integrity Unit, Children's Medical Research Institute, The University of Sydney, Westmead, NSW, Australia
| | - Anthony J Cesare
- Genome Integrity Unit, Children's Medical Research Institute, The University of Sydney, Westmead, NSW, Australia
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16
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Pumilio proteins utilize distinct regulatory mechanisms to achieve complementary functions required for pluripotency and embryogenesis. Proc Natl Acad Sci U S A 2020; 117:7851-7862. [PMID: 32198202 DOI: 10.1073/pnas.1916471117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Gene regulation in embryonic stem cells (ESCs) has been extensively studied at the epigenetic-transcriptional level, but not at the posttranscriptional level. Pumilio (Pum) proteins are among the few known translational regulators required for stem-cell maintenance in invertebrates and plants. Here we report the essential function of two murine Pum proteins, Pum1 and Pum2, in ESCs and early embryogenesis. Pum1/2 double-mutant ESCs display severely reduced self-renewal and differentiation, and Pum1/2 double-mutant mice are developmentally delayed at the morula stage and lethal by embryonic day 8.5. Remarkably, Pum1-deficient ESCs show increased expression of pluripotency genes but not differentiation genes, whereas Pum2-deficient ESCs show decreased pluripotency markers and accelerated differentiation. Thus, despite their high homology and overlapping target messenger RNAs (mRNAs), Pum1 promotes differentiation while Pum2 promotes self-renewal in ESCs. Pum1 and Pum2 achieve these two complementary aspects of pluripotency by forming a negative interregulatory feedback loop that directly regulates at least 1,486 mRNAs. Pum1 and Pum2 regulate target mRNAs not only by repressing translation, but also by promoting translation and enhancing or reducing mRNA stability of different target mRNAs. Together, these findings reveal distinct roles of individual mammalian Pum proteins in ESCs and their essential functions in ESC pluripotency and embryogenesis.
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17
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18
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Bloom JC, Loehr AR, Schimenti JC, Weiss RS. Germline genome protection: implications for gamete quality and germ cell tumorigenesis. Andrology 2019; 7:516-526. [PMID: 31119900 DOI: 10.1111/andr.12651] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/25/2019] [Accepted: 04/26/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND Germ cells have a unique and critical role as the conduit for hereditary information and therefore employ multiple strategies to protect genomic integrity and avoid mutations. Unlike somatic cells, which often respond to DNA damage by arresting the cell cycle and conducting DNA repair, germ cells as well as long-lived pluripotent stem cells typically avoid the use of error-prone repair mechanisms and favor apoptosis, reducing the risk of genetic alterations. Testicular germ cell tumors, the most common cancers of young men, arise from pre-natal germ cells. OBJECTIVES To summarize the current understanding of DNA damage response mechanisms in pre-meiotic germ cells and to discuss how they impact both the origins of testicular germ cell tumors and their remarkable responsiveness to genotoxic chemotherapy. MATERIALS AND METHODS We conducted a review of literature gathered from PubMed regarding the DNA damage response properties of testicular germ cell tumors and the germ cells from which they arise, as well as the influence of these mechanisms on therapeutic responses by testicular germ cell tumors. RESULTS AND DISCUSSION This review provides a comprehensive evaluation of how the developmental origins of male germ cells and their inherent germ cell-like DNA damage response directly impact the development and therapeutic sensitivity of testicular germ cell tumors. CONCLUSIONS The DNA damage response of germ cells directly impacts the development and therapeutic sensitivity of testicular germ cell tumors. Recent advances in the study of primordial germ cells, post-natal mitotically dividing germ cells, and pluripotent stem cells will allow for new investigations into the initiation, progression, and treatment of testicular germ cell tumors.
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Affiliation(s)
- J C Bloom
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, USA
| | - A R Loehr
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, USA
| | - J C Schimenti
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, USA
| | - R S Weiss
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, USA
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19
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Petropoulos M, Champeris Tsaniras S, Taraviras S, Lygerou Z. Replication Licensing Aberrations, Replication Stress, and Genomic Instability. Trends Biochem Sci 2019; 44:752-764. [PMID: 31054805 DOI: 10.1016/j.tibs.2019.03.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 03/24/2019] [Accepted: 03/27/2019] [Indexed: 01/07/2023]
Abstract
Strict regulation of DNA replication is of fundamental significance for the maintenance of genome stability. Licensing of origins of DNA replication is a critical event for timely genome duplication. Errors in replication licensing control lead to genomic instability across evolution. Here, we present accumulating evidence that aberrant replication licensing is linked to oncogene-induced replication stress and poses a major threat to genome stability, promoting tumorigenesis. Oncogene activation can lead to defects in where along the genome and when during the cell cycle licensing takes place, resulting in replication stress. We also discuss the potential of replication licensing as a specific target for novel anticancer therapies.
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Affiliation(s)
- Michalis Petropoulos
- Department of Biology, School of Medicine, University of Patras, Patras 26504, Greece
| | | | - Stavros Taraviras
- Department of Physiology, School of Medicine, University of Patras, Patras 26504, Greece.
| | - Zoi Lygerou
- Department of Biology, School of Medicine, University of Patras, Patras 26504, Greece.
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20
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Kalogeropoulou A, Lygerou Z, Taraviras S. Cortical Development and Brain Malformations: Insights From the Differential Regulation of Early Events of DNA Replication. Front Cell Dev Biol 2019; 7:29. [PMID: 30915332 PMCID: PMC6421272 DOI: 10.3389/fcell.2019.00029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 02/20/2019] [Indexed: 12/27/2022] Open
Abstract
During the development of the cortex distinct populations of Neural Stem Cells (NSCs) are defined by differences in their cell cycle duration, self-renewal capacity and transcriptional profile. A key difference across the distinct populations of NSCs is the length of G1 phase, where the licensing of the DNA replication origins takes place by the assembly of a pre-replicative complex. Licensing of DNA replication is a process that is adapted accordingly to the cell cycle length of NSCs to secure the timed duplication of the genome. Moreover, DNA replication should be efficiently coordinated with ongoing transcription for the prevention of conflicts that would impede the progression of both processes, compromising the normal course of development. In the present review we discuss how the differential regulation of the licensing and initiation of DNA replication in different cortical NSCs populations is integrated with the properties of these stem cells populations. Moreover, we examine the implication of the initial steps of DNA replication in the pathogenetic mechanisms of neurodevelopmental defects and Zika virus-related microcephaly, highlighting the significance of the differential regulation of DNA replication during brain development.
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Affiliation(s)
| | - Zoi Lygerou
- Department of General Biology, Medical School, University of Patras, Patras, Greece
| | - Stavros Taraviras
- Department of Physiology, Medical School, University of Patras, Patras, Greece
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21
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Voutsinos V, Munk SHN, Oestergaard VH. Common Chromosomal Fragile Sites-Conserved Failure Stories. Genes (Basel) 2018; 9:E580. [PMID: 30486458 PMCID: PMC6315858 DOI: 10.3390/genes9120580] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/19/2018] [Accepted: 11/21/2018] [Indexed: 12/17/2022] Open
Abstract
In order to pass on an intact copy of the genome during cell division, complete and faithful DNA replication is crucial. Yet, certain areas of the genome are intrinsically challenging to replicate, which manifests as high local mutation propensity. Such regions include trinucleotide repeat sequences, common chromosomal fragile sites (CFSs), and early replicating fragile sites (ERFSs). Despite their genomic instability CFSs are conserved, suggesting that they have a biological function. To shed light on the potential function of CFSs, this review summarizes the similarities and differences of the regions that challenge DNA replication with main focus on CFSs. Moreover, we review the mechanisms that operate when CFSs fail to complete replication before entry into mitosis. Finally, evolutionary perspectives and potential physiological roles of CFSs are discussed with emphasis on their potential role in neurogenesis.
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Affiliation(s)
- Vasileios Voutsinos
- Department of Biology, University of Copenhagen, 2200 Copenhagen N, Denmark.
| | - Sebastian H N Munk
- Department of Biology, University of Copenhagen, 2200 Copenhagen N, Denmark.
| | - Vibe H Oestergaard
- Department of Biology, University of Copenhagen, 2200 Copenhagen N, Denmark.
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22
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Courtot L, Hoffmann JS, Bergoglio V. The Protective Role of Dormant Origins in Response to Replicative Stress. Int J Mol Sci 2018; 19:ijms19113569. [PMID: 30424570 PMCID: PMC6274952 DOI: 10.3390/ijms19113569] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 11/05/2018] [Accepted: 11/07/2018] [Indexed: 02/07/2023] Open
Abstract
Genome stability requires tight regulation of DNA replication to ensure that the entire genome of the cell is duplicated once and only once per cell cycle. In mammalian cells, origin activation is controlled in space and time by a cell-specific and robust program called replication timing. About 100,000 potential replication origins form on the chromatin in the gap 1 (G1) phase but only 20⁻30% of them are active during the DNA replication of a given cell in the synthesis (S) phase. When the progress of replication forks is slowed by exogenous or endogenous impediments, the cell must activate some of the inactive or "dormant" origins to complete replication on time. Thus, the many origins that may be activated are probably key to protect the genome against replication stress. This review aims to discuss the role of these dormant origins as safeguards of the human genome during replicative stress.
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Affiliation(s)
- Lilas Courtot
- CRCT, Université de Toulouse, Inserm, CNRS, UPS; Equipe labellisée Ligue Contre le Cancer, Laboratoire d'excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037 Toulouse, France.
| | - Jean-Sébastien Hoffmann
- CRCT, Université de Toulouse, Inserm, CNRS, UPS; Equipe labellisée Ligue Contre le Cancer, Laboratoire d'excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037 Toulouse, France.
| | - Valérie Bergoglio
- CRCT, Université de Toulouse, Inserm, CNRS, UPS; Equipe labellisée Ligue Contre le Cancer, Laboratoire d'excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037 Toulouse, France.
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23
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Aze A, Maiorano D. Recent advances in understanding DNA replication: cell type-specific adaptation of the DNA replication program. F1000Res 2018; 7. [PMID: 30228862 PMCID: PMC6117848 DOI: 10.12688/f1000research.15408.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/20/2018] [Indexed: 12/11/2022] Open
Abstract
DNA replication is an essential process occurring prior to cell division. Cell division coupled to proliferation ensures the growth and renewal of a large variety of specialized cell types generated during embryonic development. Changes in the DNA replication program occur during development. Embryonic undifferentiated cells show a high replication rate and fast proliferation, whereas more differentiated cells are characterized by reduced DNA synthesis and a low proliferation rate. Hence, the DNA replication program must adapt to the specific features of cells committed to different fates. Recent findings on DNA synthesis regulation in different cell types open new perspectives for developing efficient and more adapted therapies to treat various diseases such as genetic diseases and cancer. This review will put the emphasis on recent progress made in this field.
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Affiliation(s)
- Antoine Aze
- Institute of Human Genetics, UMR9002, CNRS-University of Montpellier, Montpellier, 34396 Cedex 5, France
| | - Domenico Maiorano
- Institute of Human Genetics, UMR9002, CNRS-University of Montpellier, Montpellier, 34396 Cedex 5, France
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24
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Chemotherapy-Induced Depletion of OCT4-Positive Cancer Stem Cells in a Mouse Model of Malignant Testicular Cancer. Cell Rep 2018; 21:1896-1909. [PMID: 29141221 DOI: 10.1016/j.celrep.2017.10.078] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 08/27/2017] [Accepted: 10/20/2017] [Indexed: 12/22/2022] Open
Abstract
Testicular germ cell tumors (TGCTs) are among the most responsive solid cancers to conventional chemotherapy. To elucidate the underlying mechanisms, we developed a mouse TGCT model featuring germ cell-specific Kras activation and Pten inactivation. The resulting mice developed malignant, metastatic TGCTs composed of teratoma and embryonal carcinoma, the latter of which exhibited stem cell characteristics, including expression of the pluripotency factor OCT4. Consistent with epidemiological data linking human testicular cancer risk to in utero exposures, embryonic germ cells were susceptible to malignant transformation, whereas adult germ cells underwent apoptosis in response to the same oncogenic events. Treatment of tumor-bearing mice with genotoxic chemotherapy not only prolonged survival and reduced tumor size but also selectively eliminated the OCT4-positive cancer stem cells. We conclude that the chemosensitivity of TGCTs derives from the sensitivity of their cancer stem cells to DNA-damaging chemotherapy.
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25
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Cyclin K regulates prereplicative complex assembly to promote mammalian cell proliferation. Nat Commun 2018; 9:1876. [PMID: 29760377 PMCID: PMC5951916 DOI: 10.1038/s41467-018-04258-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 04/16/2018] [Indexed: 12/14/2022] Open
Abstract
The assembly of prereplicative complex (pre-RC) during G1 phase must be tightly controlled to sustain cell proliferation and maintain genomic stability. Mechanisms to prevent pre-RC formation in G2/M and S phases are well appreciated, whereas how cells ensure efficient pre-RC assembly during G1 is less clear. Here we report that cyclin K regulates pre-RC formation. We find that cyclin K expression positively correlates with cell proliferation, and knockdown of cyclin K or its cognate kinase CDK12 prevents the assembly of pre-RC in G1 phase. Mechanistically we uncover that cyclin K promotes pre-RC assembly by restricting cyclin E1 activity in G1. We identify a cyclin K-dependent, novel phosphorylation site in cyclin E1 that disrupts its interaction with CDK2. Importantly, this antagonistic relationship is largely recapitulated in cyclin E1-overexpressing tumors. We discuss the implications of our findings in light of recent reports linking cyclin K and CDK12 to human tumorigenesis. Prereplicative complex (pre-RC) formation during G1 is fundamental for cell replication. Here the authors report a role for cyclin K in regulating pre-RC formation in mammalian cells by affecting cyclin E1 activity.
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26
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Carroll TD, Newton IP, Chen Y, Blow JJ, Näthke I. Lgr5 + intestinal stem cells reside in an unlicensed G 1 phase. J Cell Biol 2018; 217:1667-1685. [PMID: 29599208 PMCID: PMC5940300 DOI: 10.1083/jcb.201708023] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 01/23/2018] [Accepted: 02/27/2018] [Indexed: 12/21/2022] Open
Abstract
During late mitosis and the early G1 phase, the origins of replication are licensed by binding to double hexamers of MCM2-7. In this study, we investigated how licensing and proliferative commitment are coupled in the epithelium of the small intestine. We developed a method for identifying cells in intact tissue containing DNA-bound MCM2-7. Interphase cells above the transit-amplifying compartment had no DNA-bound MCM2-7, but still expressed the MCM2-7 protein, suggesting that licensing is inhibited immediately upon differentiation. Strikingly, we found most proliferative Lgr5+ stem cells are in an unlicensed state. This suggests that the elongated cell-cycle of intestinal stem cells is caused by an increased G1 length, characterized by dormant periods with unlicensed origins. Significantly, the unlicensed state is lost in Apc-mutant epithelium, which lacks a functional restriction point, causing licensing immediately upon G1 entry. We propose that the unlicensed G1 phase of intestinal stem cells creates a temporal window when proliferative fate decisions can be made.
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Affiliation(s)
- Thomas D Carroll
- Cell and Developmental Biology, University of Dundee, Dundee, Scotland, UK
| | - Ian P Newton
- Cell and Developmental Biology, University of Dundee, Dundee, Scotland, UK
| | - Yu Chen
- Cell and Developmental Biology, University of Dundee, Dundee, Scotland, UK
| | - J Julian Blow
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, Scotland, UK
| | - Inke Näthke
- Cell and Developmental Biology, University of Dundee, Dundee, Scotland, UK
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27
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Zhao B, Zhang W, Cun Y, Li J, Liu Y, Gao J, Zhu H, Zhou H, Zhang R, Zheng P. Mouse embryonic stem cells have increased capacity for replication fork restart driven by the specific Filia-Floped protein complex. Cell Res 2017; 28:69-89. [PMID: 29125140 DOI: 10.1038/cr.2017.139] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 07/12/2017] [Accepted: 08/22/2017] [Indexed: 12/15/2022] Open
Abstract
Pluripotent stem cells (PSCs) harbor constitutive DNA replication stress during their rapid proliferation and the consequent genome instability hampers their applications in regenerative medicine. It is therefore important to understand the regulatory mechanisms of replication stress response in PSCs. Here, we report that mouse embryonic stem cells (ESCs) are superior to differentiated cells in resolving replication stress. Specifically, ESCs utilize a unique Filia-Floped protein complex-dependent mechanism to efficiently promote the restart of stalled replication forks, therefore maintaining genomic stability. The ESC-specific Filia-Floped complex resides on replication forks under normal conditions. Replication stress stimulates their recruitment to stalling forks and the serine 151 residue of Filia is phosphorylated in an ATR-dependent manner. This modification enables the Filia-Floped complex to act as a functional scaffold, which then promotes the stalling fork restart through a dual mechanism: both enhancing recruitment of the replication fork restart protein, Blm, and stimulating ATR kinase activation. In the Blm pathway, the scaffolds recruit the E3 ubiquitin ligase, Trim25, to the stalled replication forks, and in turn Trim25 tethers and concentrates Blm at stalled replication forks through ubiquitination. In differentiated cells, the recruitment of the Trim25-Blm complex to replication forks and the activation of ATR signaling are much less robust due to lack of the ESC-specific Filia-Floped scaffold. Thus, our study reveals that ESCs utilize an additional and unique regulatory layer to efficiently promote the stalled fork restart and maintain genomic stability.
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Affiliation(s)
- Bo Zhao
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.,Yunnan Key Laboratory of Animal Reproduction, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Weidao Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.,Yunnan Key Laboratory of Animal Reproduction, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Yixian Cun
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Jingzheng Li
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.,Yunnan Key Laboratory of Animal Reproduction, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Yan Liu
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.,Yunnan Key Laboratory of Animal Reproduction, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Jing Gao
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Hongwen Zhu
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Hu Zhou
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Rugang Zhang
- Gene Expression and Regulation Program, The Wistar Institute Cancer Center, The Wistar Institute, Philadelphia, PA 19104, USA
| | - Ping Zheng
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.,Yunnan Key Laboratory of Animal Reproduction, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
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Shima N, Pederson KD. Dormant origins as a built-in safeguard in eukaryotic DNA replication against genome instability and disease development. DNA Repair (Amst) 2017; 56:166-173. [PMID: 28641940 PMCID: PMC5547906 DOI: 10.1016/j.dnarep.2017.06.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
DNA replication is a prerequisite for cell proliferation, yet it can be increasingly challenging for a eukaryotic cell to faithfully duplicate its genome as its size and complexity expands. Dormant origins now emerge as a key component for cells to successfully accomplish such a demanding but essential task. In this perspective, we will first provide an overview of the fundamental processes eukaryotic cells have developed to regulate origin licensing and firing. With a special focus on mammalian systems, we will then highlight the role of dormant origins in preventing replication-associated genome instability and their functional interplay with proteins involved in the DNA damage repair response for tumor suppression. Lastly, deficiencies in the origin licensing machinery will be discussed in relation to their influence on stem cell maintenance and human diseases.
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Affiliation(s)
- Naoko Shima
- The University of Minnesota, Twin Cities, Department of Genetics, Cell Biology and Development, Masonic Cancer Center, 6-160 Jackson Hall, 321 Church St SE., Minneapolis, MN 55455, United States.
| | - Kayla D Pederson
- The University of Minnesota, Twin Cities, Department of Genetics, Cell Biology and Development, Masonic Cancer Center, 6-160 Jackson Hall, 321 Church St SE., Minneapolis, MN 55455, United States
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Hosogane M, Bosu L, Fukumoto E, Yamada H, Sato S, Nakayama K. Geminin is an indispensable inhibitor of Cdt1 in mouse embryonic stem cells. Genes Cells 2017; 22:360-375. [DOI: 10.1111/gtc.12482] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 01/26/2017] [Indexed: 11/26/2022]
Affiliation(s)
- Masaki Hosogane
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Lena Bosu
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Emiko Fukumoto
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Hidetoshi Yamada
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Soichiro Sato
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Keiko Nakayama
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
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Regulation of DNA Replication in Early Embryonic Cleavages. Genes (Basel) 2017; 8:genes8010042. [PMID: 28106858 PMCID: PMC5295036 DOI: 10.3390/genes8010042] [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: 11/25/2016] [Revised: 01/06/2017] [Accepted: 01/11/2017] [Indexed: 11/18/2022] Open
Abstract
Early embryonic cleavages are characterized by short and highly synchronous cell cycles made of alternating S- and M-phases with virtually absent gap phases. In this contracted cell cycle, the duration of DNA synthesis can be extraordinarily short. Depending on the organism, the whole genome of an embryo is replicated at a speed that is between 20 to 60 times faster than that of a somatic cell. Because transcription in the early embryo is repressed, DNA synthesis relies on a large stockpile of maternally supplied proteins stored in the egg representing most, if not all, cellular genes. In addition, in early embryonic cell cycles, both replication and DNA damage checkpoints are inefficient. In this article, we will review current knowledge on how DNA synthesis is regulated in early embryos and discuss possible consequences of replicating chromosomes with little or no quality control.
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Festuccia N, Gonzalez I, Navarro P. The Epigenetic Paradox of Pluripotent ES Cells. J Mol Biol 2016; 429:1476-1503. [PMID: 27988225 DOI: 10.1016/j.jmb.2016.12.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/02/2016] [Accepted: 12/05/2016] [Indexed: 12/15/2022]
Abstract
The propagation and maintenance of gene expression programs are at the foundation of the preservation of cell identity. A large and complex set of epigenetic mechanisms enables the long-term stability and inheritance of transcription states. A key property of authentic epigenetic regulation is being independent from the instructive signals used for its establishment. This makes epigenetic regulation, particularly epigenetic silencing, extremely robust and powerful to lock regulatory states and stabilise cell identity. In line with this, the establishment of epigenetic silencing during development restricts cell potency and maintains the cell fate choices made by transcription factors (TFs). However, how more immature cells that have not yet established their definitive fate maintain their transitory identity without compromising their responsiveness to signalling cues remains unclear. A paradigmatic example is provided by pluripotent embryonic stem (ES) cells derived from a transient population of cells of the blastocyst. Here, we argue that ES cells represent an interesting "epigenetic paradox": even though they are captured in a self-renewing state characterised by extremely efficient maintenance of their identity, which is a typical manifestation of robust epigenetic regulation, they seem not to heavily rely on classical epigenetic mechanisms. Indeed, self-renewal strictly depends on the TFs that previously instructed their undifferentiated identity and relies on a particular signalling-dependent chromatin state where repressive chromatin marks play minor roles. Although this "epigenetic paradox" may underlie their exquisite responsiveness to developmental cues, it suggests that alternative mechanisms to faithfully propagate gene regulatory states might be prevalent in ES cells.
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Affiliation(s)
- Nicola Festuccia
- Epigenetics of Stem Cells, Department of Stem Cell and Developmental Biology, Institut Pasteur, CNRS UMR3738, 25 rue du Docteur Roux, 75015 Paris, France
| | - Inma Gonzalez
- Epigenetics of Stem Cells, Department of Stem Cell and Developmental Biology, Institut Pasteur, CNRS UMR3738, 25 rue du Docteur Roux, 75015 Paris, France
| | - Pablo Navarro
- Epigenetics of Stem Cells, Department of Stem Cell and Developmental Biology, Institut Pasteur, CNRS UMR3738, 25 rue du Docteur Roux, 75015 Paris, France.
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Stevanoni M, Palumbo E, Russo A. The Replication of Frataxin Gene Is Assured by Activation of Dormant Origins in the Presence of a GAA-Repeat Expansion. PLoS Genet 2016; 12:e1006201. [PMID: 27447727 PMCID: PMC4957762 DOI: 10.1371/journal.pgen.1006201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 06/27/2016] [Indexed: 12/17/2022] Open
Abstract
It is well known that DNA replication affects the stability of several trinucleotide repeats, but whether replication profiles of human loci carrying an expanded repeat differ from those of normal alleles is poorly understood in the endogenous context. We investigated this issue using cell lines from Friedreich's ataxia patients, homozygous for a GAA-repeat expansion in intron 1 of the Frataxin gene. By interphase, FISH we found that in comparison to the normal Frataxin sequence the replication of expanded alleles is slowed or delayed. According to molecular combing, origins never fired within the normal Frataxin allele. In contrast, in mutant alleles dormant origins are recruited within the gene, causing a switch of the prevalent fork direction through the expanded repeat. Furthermore, a global modification of the replication profile, involving origin choice and a differential distribution of unidirectional forks, was observed in the surrounding 850 kb region. These data provide a wide-view of the interplay of events occurring during replication of genes carrying an expanded repeat.
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Affiliation(s)
| | - Elisa Palumbo
- Department of Biology, University of Padova, Padova, Italy
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Abstract
The mechanism that duplicates the nuclear genome during the trillions of cell divisions required to develop from zygote to adult is the same throughout the eukarya, but the mechanisms that determine where, when and how much nuclear genome duplication occur regulate development and differ among the eukarya. They allow organisms to change the rate of cell proliferation during development, to activate zygotic gene expression independently of DNA replication, and to restrict nuclear DNA replication to once per cell division. They allow specialized cells to exit their mitotic cell cycle and differentiate into polyploid cells, and in some cases, to amplify the number of copies of specific genes. It is genome duplication that drives evolution, by virtue of the errors that inevitably occur when the same process is repeated trillions of times. It is, unfortunately, the same errors that produce age-related genetic disorders such as cancer.
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Affiliation(s)
- Melvin L DePamphilis
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA.
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