1
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Tolbatov I, Umari P, Marrone A. The binding of diruthenium (II,III) and dirhodium (II,II) paddlewheel complexes at DNA/RNA nucleobases: Computational evidences of an appreciable selectivity toward the AU base pairs. J Mol Graph Model 2024; 131:108806. [PMID: 38824876 DOI: 10.1016/j.jmgm.2024.108806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 05/21/2024] [Accepted: 05/28/2024] [Indexed: 06/04/2024]
Abstract
Multiple medicinal strategies involve modifications of the structure of DNA or RNA, which disrupt their correct functioning. Metal complexes with medicinal effects, also known as metallodrugs, are among the agents intended specifically for the attack onto nucleosides. The diruthenium (II,III) and dirhodium (II,II) paddlewheel complexes constitute promising dual acting drugs due to their ability to release the therapeutically active bridging ligands upon their substitution by endogenous ligands. In this paper, we study the structure and the stability of the complexes formed by the diruthenium (II,III) and dirhodium (II,II) paddlewheel complexes coordinated in axial positions with the DNA/RNA nucleobases or base pairs, assuming the attainable metalation at all the accessible pyridyl nitrogens. Dirhodium complexes coordinate at the pyridyl nitrogens more strongly than the diruthenium complexes. On the other hand, we found that the diruthenium scaffold binds more selectively to nucleobase targets. Furthermore, we reveal a tighter coordination of diruthenium complex at the adenine-uracil base pair, compared to adenine-thymine, hence constituting a scarce instance of RNA-selectivity. We envision that the here reported computational outcomes may pace future experiments addressing the binding of diruthenium and dirhodium paddlewheel complexes at either single nucleobases or DNA/RNA fragments.
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Affiliation(s)
- Iogann Tolbatov
- Department of Physics and Astronomy, University of Padova, via F. Marzolo 8, 35131, Padova, Italy.
| | - Paolo Umari
- Department of Physics and Astronomy, University of Padova, via F. Marzolo 8, 35131, Padova, Italy
| | - Alessandro Marrone
- Dipartimento di Farmacia, Università degli Studi "G. D'Annunzio" Chieti-Pescara, Via dei Vestini, 66100, Chieti, Italy
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2
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Zhang Q, Lam WH, Zhai Y. Assembly and activation of replicative helicases at origin DNA for replication initiation. Curr Opin Struct Biol 2024; 88:102876. [PMID: 38986167 DOI: 10.1016/j.sbi.2024.102876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 06/01/2024] [Accepted: 06/14/2024] [Indexed: 07/12/2024]
Abstract
To initiate DNA replication, it is essential to properly assemble a pair of replicative helicases at each replication origin. While the general principle of this process applies universally from prokaryotes to eukaryotes, the specific mechanisms governing origin selection, helicase loading, and subsequent helicase activation vary significantly across different species. Recent advancements in cryo-electron microscopy (cryo-EM) have revolutionized our ability to visualize large protein or protein-DNA complexes involved in the initiation of DNA replication. Complemented by real-time single-molecule analysis, the available high-resolution cryo-EM structures have greatly enhanced our understanding of the dynamic regulation of this process at origin DNA. This review primarily focuses on the latest structural discoveries that shed light on the key molecular machineries responsible for driving replication initiation, with a particular emphasis on the assembly of pre-replication complex (pre-RC) in eukaryotes.
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Affiliation(s)
- Qiongdan Zhang
- School of Biological Sciences, The University of Hong Kong, Hong Kong
| | - Wai Hei Lam
- School of Biological Sciences, The University of Hong Kong, Hong Kong
| | - Yuanliang Zhai
- School of Biological Sciences, The University of Hong Kong, Hong Kong.
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3
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Karagyozova T, Almouzni G. Replicating chromatin in the nucleus: A histone variant perspective. Curr Opin Cell Biol 2024; 89:102397. [PMID: 38981199 DOI: 10.1016/j.ceb.2024.102397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 06/07/2024] [Accepted: 06/17/2024] [Indexed: 07/11/2024]
Abstract
In eukaryotes, chromatin and DNA replication are intimately linked, whereby chromatin impacts DNA replication control while genome duplication involves recovery of chromatin organisation. Here, we review recent advances in this area using a histone variant lens. We highlight how nucleosomal features interplay with origin definition and how the order of origin firing links with chromatin states in early mammalian development. We next discuss histone recycling and de novo deposition at the fork to finally open on the post-replicative recovery of the chromatin landscape to promote maintenance of cell identity.
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Affiliation(s)
- Tina Karagyozova
- Institut Curie, PSL Research University, CNRS, Sorbonne Université, Nuclear Dynamics Unit, Equipe Labellisée Ligue Contre le Cancer, 26 rue d'Ulm, 75005 Paris, France
| | - Geneviève Almouzni
- Institut Curie, PSL Research University, CNRS, Sorbonne Université, Nuclear Dynamics Unit, Equipe Labellisée Ligue Contre le Cancer, 26 rue d'Ulm, 75005 Paris, France.
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4
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Feng J, Chuah Y, Liang Y, Cipta N, Zeng Y, Warrier T, Elfar G, Yoon J, Grinchuk O, Tay E, Lok KZ, Zheng ZQ, Khong Z, Chong ZS, Teo J, Sanford E, Neo C, Chiu H, Leung J, Wang L, Lim Y, Zhao T, Sobota R, Crasta K, Tergaonkar V, Taneja R, Ng SY, Cheok C, Ling SC, Loh YH, Ong D. PHF2 regulates genome topology and DNA replication in neural stem cells via cohesin. Nucleic Acids Res 2024; 52:7063-7080. [PMID: 38808662 PMCID: PMC11229317 DOI: 10.1093/nar/gkae457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 04/15/2024] [Accepted: 05/15/2024] [Indexed: 05/30/2024] Open
Abstract
Cohesin plays a crucial role in the organization of topologically-associated domains (TADs), which influence gene expression and DNA replication timing. Whether epigenetic regulators may affect TADs via cohesin to mediate DNA replication remains elusive. Here, we discover that the histone demethylase PHF2 associates with RAD21, a core subunit of cohesin, to regulate DNA replication in mouse neural stem cells (NSC). PHF2 loss impairs DNA replication due to the activation of dormant replication origins in NSC. Notably, the PHF2/RAD21 co-bound genomic regions are characterized by CTCF enrichment and epigenomic features that resemble efficient, active replication origins, and can act as boundaries to separate adjacent domains. Accordingly, PHF2 loss weakens TADs and chromatin loops at the co-bound loci due to reduced RAD21 occupancy. The observed topological and DNA replication defects in PHF2 KO NSC support a cohesin-dependent mechanism. Furthermore, we demonstrate that the PHF2/RAD21 complex exerts little effect on gene regulation, and that PHF2's histone-demethylase activity is dispensable for normal DNA replication and proliferation of NSC. We propose that PHF2 may serve as a topological accessory to cohesin for cohesin localization to TADs and chromatin loops, where cohesin represses dormant replication origins directly or indirectly, to sustain DNA replication in NSC.
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Affiliation(s)
- Jia Feng
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - You Heng Chuah
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- NUS Centre for Cancer Research Translation Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Yajing Liang
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - Nadia Omega Cipta
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
| | - Yingying Zeng
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
| | - Tushar Warrier
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
| | - Gamal Ahmed Rashed Elsayed Elfar
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, National University Hospital, Singapore 119074, Singapore
| | - Jeehyun Yoon
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- NUS Centre for Cancer Research Translation Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Oleg V Grinchuk
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- NUS Centre for Cancer Research Translation Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Emmy Xue Yun Tay
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - Ker-Zhing Lok
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - Zong-Qing Zheng
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - Zi Jian Khong
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
| | - Zheng-Shan Chong
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
| | - Jackie Teo
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
| | - Emma May Sanford
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- Healthy Longevity Translation Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Cheryl Jia Yi Neo
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- Healthy Longevity Translation Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Hsin Yao Chiu
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - Jia Yu Leung
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, National University Hospital, Singapore 119074, Singapore
| | - Loo Chien Wang
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
| | - Yan Ting Lim
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
| | - Tianyun Zhao
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
| | - Radoslaw M Sobota
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
| | - Karen Carmelina Crasta
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- NUS Centre for Cancer Research Translation Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
- Healthy Longevity Translation Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Vinay Tergaonkar
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, MD7, Singapore 117596, Singapore
- Laboratory of NFκB Signalling, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
| | - Reshma Taneja
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- NUS Centre for Cancer Research Translation Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Healthy Longevity Translation Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Shi-Yan Ng
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
- National Neuroscience Institute, 308433, Singapore
| | - Chit Fang Cheok
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, National University Hospital, Singapore 119074, Singapore
| | - Shuo-Chien Ling
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- Healthy Longevity Translation Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Yuin-Han Loh
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Derrick Sek Tong Ong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- NUS Centre for Cancer Research Translation Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138673, Singapore
- Healthy Longevity Translation Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- National Neuroscience Institute, 308433, Singapore
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5
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Zhu X, Kanemaki MT. Replication initiation sites and zones in the mammalian genome: Where are they located and how are they defined? DNA Repair (Amst) 2024; 141:103713. [PMID: 38959715 DOI: 10.1016/j.dnarep.2024.103713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 06/14/2024] [Accepted: 06/15/2024] [Indexed: 07/05/2024]
Abstract
Eukaryotic DNA replication is a tightly controlled process that occurs in two main steps, i.e., licensing and firing, which take place in the G1 and S phases of the cell cycle, respectively. In Saccharomyces cerevisiae, the budding yeast, replication origins contain consensus sequences that are recognized and bound by the licensing factor Orc1-6, which then recruits the replicative Mcm2-7 helicase. By contrast, mammalian initiation sites lack such consensus sequences, and the mammalian ORC does not exhibit sequence specificity. Studies performed over the past decades have identified replication initiation sites in the mammalian genome using sequencing-based assays, raising the question of whether replication initiation occurs at confined sites or in broad zones across the genome. Although recent reports have shown that the licensed MCMs in mammalian cells are broadly distributed, suggesting that ORC-dependent licensing may not determine the initiation sites/zones, they are predominantly located upstream of actively transcribed genes. This review compares the mechanism of replication initiation in yeast and mammalian cells, summarizes the sequencing-based technologies used for the identification of initiation sites/zones, and proposes a possible mechanism of initiation-site/zone selection in mammalian cells. Future directions and challenges in this field are also discussed.
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Affiliation(s)
- Xiaoxuan Zhu
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Yata 1111, Shizuoka, Mishima 411-8540, Japan.
| | - Masato T Kanemaki
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Yata 1111, Shizuoka, Mishima 411-8540, Japan; Graduate Institute for Advanced Studies, SOKENDAI, Yata 1111, Shizuoka, Mishima 411-8540, Japan; Department of Biological Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
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6
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Reed TT, Kendal AH, Wozniak KJ, Simmons LA. DNA replication initiation timing is important for maintaining genome integrity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.18.599555. [PMID: 38948856 PMCID: PMC11212987 DOI: 10.1101/2024.06.18.599555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
DNA replication is regulated by factors that promote or inhibit initiation. In Bacillus subtilis, YabA is a negative regulator of DNA replication initiation while the newly identified kinase CcrZ is a positive regulator. The consequences of under-initiation or over-initiation of DNA replication to genome stability remain unclear. In this work, we measure origin to terminus ratios as a proxy for replication initiation activity. We show that ΔccrZ and several ccrZ alleles under-initiate DNA replication while ablation of yabA or overproduction of CcrZ leads to over-initiation. We find that cells under-initiating DNA replication have few incidents of replication fork stress as determined by low formation of RecA-GFP foci compared with wild type. In contrast, cells over-initiating DNA replication show levels of RecA-GFP foci formation analogous to cells directly challenged with DNA damaging agents. We show that cells under-initiating and over-initiating DNA replication were both sensitive to mitomycin C and that changes in replication initiation frequency cause increased sensitivity to genotoxic stress. With these results, we propose that cells under-initiating DNA replication are sensitive to DNA damage due to a shortage of DNA for repair through homologous recombination. For cells over-initiating DNA replication, we propose that an increase in the number of replication forks leads to replication fork stress which is further exacerbated by chromosomal DNA damage. Together, our study shows that DNA replication initiation frequency must be tightly controlled as changes in initiation influence replication fork fate and the capacity of cells to efficiently repair damage to their genetic material.
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Affiliation(s)
- Tristan T. Reed
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Abigail H. Kendal
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Katherine J Wozniak
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
- Present address: Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030
| | - Lyle A. Simmons
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
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7
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Wang Y, Liang J. Pioneer factors for DNA replication initiation in metazoans. Bioessays 2024:e2400002. [PMID: 38881154 DOI: 10.1002/bies.202400002] [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: 01/08/2024] [Revised: 05/30/2024] [Accepted: 06/04/2024] [Indexed: 06/18/2024]
Abstract
Precise DNA replication is fundamental for genetic inheritance. In eukaryotes, replication initiates at multiple origins that are first "licensed" and subsequently "fired" to activate DNA synthesis. Despite the success in identifying origins with specific DNA motifs in Saccharomyces cerevisiae, no consensus sequence or sequences with a predictive value of replication origins have been recognized in metazoan genomes. Rather, epigenetic rules and chromatin structures are believed to play important roles in governing the selection and activation of replication origins. We propose that replication initiation is facilitated by a group of sequence-specific "replication pioneer factors," which function to increase chromatin accessibility and foster a chromatin environment that is conducive to the loading of the prereplication complex. Dysregulation of the function of these factors may lead to gene duplication, genomic instability, and ultimately the occurrence of pathological conditions such as cancer.
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Affiliation(s)
- Yue Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Zhejiang Key Laboratory of Medical Epigenetics, Hangzhou Normal University, Hangzhou, China
| | - Jing Liang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
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8
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Fajri N, Petryk N. Monitoring and quantifying replication fork dynamics with high-throughput methods. Commun Biol 2024; 7:729. [PMID: 38877080 PMCID: PMC11178896 DOI: 10.1038/s42003-024-06412-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 06/04/2024] [Indexed: 06/16/2024] Open
Abstract
Before each cell division, eukaryotic cells must replicate their chromosomes to ensure the accurate transmission of genetic information. Chromosome replication involves more than just DNA duplication; it also includes chromatin assembly, inheritance of epigenetic marks, and faithful resumption of all genomic functions after replication. Recent progress in quantitative technologies has revolutionized our understanding of the complexity and dynamics of DNA replication forks at both molecular and genomic scales. Here, we highlight the pivotal role of these novel methods in uncovering the principles and mechanisms of chromosome replication. These technologies have illuminated the regulation of genome replication programs, quantified the impact of DNA replication on genomic mutations and evolutionary processes, and elucidated the mechanisms of replication-coupled chromatin assembly and epigenome maintenance.
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Affiliation(s)
- Nora Fajri
- UMR9019 - CNRS, Intégrité du Génome et Cancers, Université Paris-Saclay, Gustave Roussy, Villejuif, France, 114 rue Edouard Vaillant, 94805, Villejuif, France
| | - Nataliya Petryk
- UMR9019 - CNRS, Intégrité du Génome et Cancers, Université Paris-Saclay, Gustave Roussy, Villejuif, France, 114 rue Edouard Vaillant, 94805, Villejuif, France.
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9
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Stillman B. Establishing a biochemical understanding of the initiation of chromosome replication in bacteria. Proc Natl Acad Sci U S A 2024; 121:e2400667121. [PMID: 38758693 PMCID: PMC11161774 DOI: 10.1073/pnas.2400667121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2024] Open
Abstract
In the mid-1950s, Arthur Kornberg elucidated the enzymatic synthesis of DNA by DNA polymerase, for which he was recognized with the 1959 Nobel Prize in Physiology or Medicine. He then identified many of the proteins that cooperate with DNA polymerase to replicate duplex DNA of small bacteriophages. However, one major unanswered problem was understanding the mechanism and control of the initiation of chromosome replication in bacteria. In a seminal paper in 1981, Fuller, Kaguni, and Kornberg reported the development of a cell-free enzyme system that could replicate DNA that was dependent on the bacterial origin of DNA replication, oriC. This advance opened the door to a flurry of discoveries and important papers that elucidated the process and control of initiation of chromosome replication in bacteria.
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Affiliation(s)
- Bruce Stillman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY11724
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10
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Duardo RC, Marinello J, Russo M, Morelli S, Pepe S, Guerra F, Gómez-González B, Aguilera A, Capranico G. Human DNA topoisomerase I poisoning causes R loop-mediated genome instability attenuated by transcription factor IIS. SCIENCE ADVANCES 2024; 10:eadm8196. [PMID: 38787953 PMCID: PMC11122683 DOI: 10.1126/sciadv.adm8196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 04/18/2024] [Indexed: 05/26/2024]
Abstract
DNA topoisomerase I can contribute to cancer genome instability. During catalytic activity, topoisomerase I forms a transient intermediate, topoisomerase I-DNA cleavage complex (Top1cc) to allow strand rotation and duplex relaxation, which can lead to elevated levels of DNA-RNA hybrids and micronuclei. To comprehend the underlying mechanisms, we have integrated genomic data of Top1cc-triggered hybrids and DNA double-strand breaks (DSBs) shortly after Top1cc induction, revealing that Top1ccs increase hybrid levels with different mechanisms. DSBs are at highly transcribed genes in early replicating initiation zones and overlap with hybrids downstream of accumulated RNA polymerase II (RNAPII) at gene 5'-ends. A transcription factor IIS mutant impairing transcription elongation further increased RNAPII accumulation likely due to backtracking. Moreover, Top1ccs can trigger micronuclei when occurring during late G1 or early/mid S, but not during late S. As micronuclei and transcription-replication conflicts are attenuated by transcription factor IIS, our results support a role of RNAPII arrest in Top1cc-induced transcription-replication conflicts leading to DSBs and micronuclei.
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Affiliation(s)
- Renée C. Duardo
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Jessica Marinello
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Marco Russo
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Sara Morelli
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Simona Pepe
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Federico Guerra
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa—CABIMER, Universidad de Sevilla–CSIC, Calle Américo Vespucio 24, 41092 Seville, Spain
- Departamento de Genetica, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa—CABIMER, Universidad de Sevilla–CSIC, Calle Américo Vespucio 24, 41092 Seville, Spain
- Departamento de Genetica, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Giovanni Capranico
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum–University of Bologna, via Selmi 3, 40126, Bologna, Italy
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Przanowska RK, Chen Y, Uchida TO, Shibata E, Hao X, Rueda IS, Jensen K, Przanowski P, Trimboli A, Shibata Y, Leone G, Dutta A. Endo-reduplication in mouse liver after conditional mutation of ORC2 and combined mutation of ORC1 and ORC2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.04.588006. [PMID: 38617300 PMCID: PMC11014565 DOI: 10.1101/2024.04.04.588006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
The six subunit Origin Recognition Complex (ORC) is essential for loading MCM2-7 at origins of DNA replication to promote initiation of DNA replication in organisms ranging from S. cerevisiae to humans. In rare instances, as in cancer cell-lines in culture with mutations in ORC1 , ORC2 or ORC5 , or in endo-reduplicating mouse hepatocytes in vivo without ORC1 , DNA replication has been observed in the virtual absence of individual ORC subunits. Although ORC1 is dispensable in the mouse liver for endo-reduplication, because of the homology of ORC1 with CDC6, it could be argued that CDC6 was substituting for ORC1 to restore functional ORC. Here, we have created mice with a conditional deletion of ORC2 , to demonstrate that mouse embryo fibroblasts require ORC2 for proliferation, but that the mouse hepatocytes can carry out DNA synthesis in vitro and endo-reduplicate in vivo , despite the deletion of ORC2 . Combining the conditional mutation of ORC1 and ORC2 revealed that the mouse liver can still carry out endo-reduplication despite the deletion of the two genes, both during normal development and after partial hepatectomy. Since endo-reduplication, like normal S phase replication, requires the presence of MCM2-7 on the chromatin, these results suggest that in primary hepatocytes there is a mechanism to load sufficient MCM2-7 to carry out effective DNA replication despite the virtual absence of two subunits of ORC.
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12
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Tian M, Wang Z, Su Z, Shibata E, Shibata Y, Dutta A, Zang C. Integrative analysis of DNA replication origins and ORC-/MCM-binding sites in human cells reveals a lack of overlap. eLife 2024; 12:RP89548. [PMID: 38567819 PMCID: PMC10990492 DOI: 10.7554/elife.89548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024] Open
Abstract
Based on experimentally determined average inter-origin distances of ~100 kb, DNA replication initiates from ~50,000 origins on human chromosomes in each cell cycle. The origins are believed to be specified by binding of factors like the origin recognition complex (ORC) or CTCF or other features like G-quadruplexes. We have performed an integrative analysis of 113 genome-wide human origin profiles (from five different techniques) and five ORC-binding profiles to critically evaluate whether the most reproducible origins are specified by these features. Out of ~7.5 million union origins identified by all datasets, only 0.27% (20,250 shared origins) were reproducibly obtained in at least 20 independent SNS-seq datasets and contained in initiation zones identified by each of three other techniques, suggesting extensive variability in origin usage and identification. Also, 21% of the shared origins overlap with transcriptional promoters, posing a conundrum. Although the shared origins overlap more than union origins with constitutive CTCF-binding sites, G-quadruplex sites, and activating histone marks, these overlaps are comparable or less than that of known transcription start sites, so that these features could be enriched in origins because of the overlap of origins with epigenetically open, promoter-like sequences. Only 6.4% of the 20,250 shared origins were within 1 kb from any of the ~13,000 reproducible ORC-binding sites in human cancer cells, and only 4.5% were within 1 kb of the ~11,000 union MCM2-7-binding sites in contrast to the nearly 100% overlap in the two comparisons in the yeast, Saccharomyces cerevisiae. Thus, in human cancer cell lines, replication origins appear to be specified by highly variable stochastic events dependent on the high epigenetic accessibility around promoters, without extensive overlap between the most reproducible origins and currently known ORC- or MCM-binding sites.
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Affiliation(s)
- Mengxue Tian
- Center for Public Health Genomics, University of Virginia School of MedicineCharlottesvilleUnited States
- Department of Biochemistry and Molecular Genetics, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Zhenjia Wang
- Center for Public Health Genomics, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Zhangli Su
- Department of Biochemistry and Molecular Genetics, University of Virginia School of MedicineCharlottesvilleUnited States
- Department of Genetics, University of Alabama at BirminghamBirminghamUnited States
| | - Etsuko Shibata
- Department of Biochemistry and Molecular Genetics, University of Virginia School of MedicineCharlottesvilleUnited States
- Department of Genetics, University of Alabama at BirminghamBirminghamUnited States
| | - Yoshiyuki Shibata
- Department of Biochemistry and Molecular Genetics, University of Virginia School of MedicineCharlottesvilleUnited States
- Department of Genetics, University of Alabama at BirminghamBirminghamUnited States
| | - Anindya Dutta
- Department of Biochemistry and Molecular Genetics, University of Virginia School of MedicineCharlottesvilleUnited States
- Department of Genetics, University of Alabama at BirminghamBirminghamUnited States
| | - Chongzhi Zang
- Center for Public Health Genomics, University of Virginia School of MedicineCharlottesvilleUnited States
- Department of Biochemistry and Molecular Genetics, University of Virginia School of MedicineCharlottesvilleUnited States
- Department of Public Health Sciences, University of VirginiaCharlottesvilleUnited States
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13
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Lichauco C, Foss EJ, Gatbonton-Schwager T, Athow NF, Lofts BR, Acob R, Taylor E, Lao U, Miles S, Bedalov A. Sir2 and Fun30 regulate ribosomal DNA replication timing via Mcm helicase positioning and nucleosome occupancy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.21.586113. [PMID: 38585982 PMCID: PMC10996493 DOI: 10.1101/2024.03.21.586113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
The association between late replication timing and low transcription rates in eukaryotic heterochromatin is well-known, yet the specific mechanisms underlying this link remain uncertain. In Saccharomyces cerevisiae, the histone deacetylase Sir2 is required for both transcriptional silencing and late replication at the repetitive ribosomal DNA arrays (rDNA). We have previously reported that in the absence of SIR2, a derepressed RNA PolII repositions MCM replicative helicases from their loading site at the ribosomal origin, where they abut well-positioned, high-occupancy nucleosomes, to an adjacent region with lower nucleosome occupancy. By developing a method that can distinguish activation of closely spaced MCM complexes, here we show that the displaced MCMs at rDNA origins have increased firing propensity compared to the non-displaced MCMs. Furthermore, we found that both, activation of the repositioned MCMs and low occupancy of the adjacent nucleosomes critically depend on the chromatin remodeling activity of FUN30. Our study elucidates the mechanism by which Sir2 delays replication timing, and it demonstrates, for the first time, that activation of a specific replication origin in vivo relies on the nucleosome context shaped by a single chromatin remodeler.
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Affiliation(s)
- Carmina Lichauco
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Eric J. Foss
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Tonibelle Gatbonton-Schwager
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Nelson F. Athow
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Brandon R. Lofts
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Robin Acob
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Erin Taylor
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Uyen Lao
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Shawna Miles
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Antonio Bedalov
- Translational Sciences and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
- Department of Biochemistry and Department of Medicine, University of Washington, Seattle, WA
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14
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Nasheuer HP, Meaney AM. Starting DNA Synthesis: Initiation Processes during the Replication of Chromosomal DNA in Humans. Genes (Basel) 2024; 15:360. [PMID: 38540419 PMCID: PMC10969946 DOI: 10.3390/genes15030360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/09/2024] [Accepted: 03/11/2024] [Indexed: 06/14/2024] Open
Abstract
The initiation reactions of DNA synthesis are central processes during human chromosomal DNA replication. They are separated into two main processes: the initiation events at replication origins, the start of the leading strand synthesis for each replicon, and the numerous initiation events taking place during lagging strand DNA synthesis. In addition, a third mechanism is the re-initiation of DNA synthesis after replication fork stalling, which takes place when DNA lesions hinder the progression of DNA synthesis. The initiation of leading strand synthesis at replication origins is regulated at multiple levels, from the origin recognition to the assembly and activation of replicative helicase, the Cdc45-MCM2-7-GINS (CMG) complex. In addition, the multiple interactions of the CMG complex with the eukaryotic replicative DNA polymerases, DNA polymerase α-primase, DNA polymerase δ and ε, at replication forks play pivotal roles in the mechanism of the initiation reactions of leading and lagging strand DNA synthesis. These interactions are also important for the initiation of signalling at unperturbed and stalled replication forks, "replication stress" events, via ATR (ATM-Rad 3-related protein kinase). These processes are essential for the accurate transfer of the cells' genetic information to their daughters. Thus, failures and dysfunctions in these processes give rise to genome instability causing genetic diseases, including cancer. In their influential review "Hallmarks of Cancer: New Dimensions", Hanahan and Weinberg (2022) therefore call genome instability a fundamental function in the development process of cancer cells. In recent years, the understanding of the initiation processes and mechanisms of human DNA replication has made substantial progress at all levels, which will be discussed in the review.
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Affiliation(s)
- Heinz Peter Nasheuer
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, Biochemistry, University of Galway, H91 TK33 Galway, Ireland;
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15
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Espinosa-Martínez M, Alcázar-Fabra M, Landeira D. The molecular basis of cell memory in mammals: The epigenetic cycle. SCIENCE ADVANCES 2024; 10:eadl3188. [PMID: 38416817 PMCID: PMC10901381 DOI: 10.1126/sciadv.adl3188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/26/2024] [Indexed: 03/01/2024]
Abstract
Cell memory refers to the capacity of cells to maintain their gene expression program once the initiating environmental signal has ceased. This exceptional feature is key during the formation of mammalian organisms, and it is believed to be in part mediated by epigenetic factors that can endorse cells with the landmarks required to maintain transcriptional programs upon cell duplication. Here, we review current literature analyzing the molecular basis of epigenetic memory in mammals, with a focus on the mechanisms by which transcriptionally repressive chromatin modifications such as methylation of DNA and histone H3 are propagated through mitotic cell divisions. The emerging picture suggests that cellular memory is supported by an epigenetic cycle in which reversible activities carried out by epigenetic regulators in coordination with cell cycle transition create a multiphasic system that can accommodate both maintenance of cell identity and cell differentiation in proliferating stem cell populations.
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Affiliation(s)
- Mencía Espinosa-Martínez
- Centre for Genomics and Oncological Research (GENYO), Avenue de la Ilustración 114, 18016 Granada, Spain
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| | - María Alcázar-Fabra
- Centre for Genomics and Oncological Research (GENYO), Avenue de la Ilustración 114, 18016 Granada, Spain
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
| | - David Landeira
- Centre for Genomics and Oncological Research (GENYO), Avenue de la Ilustración 114, 18016 Granada, Spain
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
- Instituto de Investigación Biosanitaria ibs.GRANADA, Granada, Spain
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16
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Zhao Y, Wang J, Liang X, Wang C. Clinical relevance of ORCs in predicting prognosis and immunotherapy outcomes: A pan-cancer analysis. Immunobiology 2024; 229:152783. [PMID: 38211410 DOI: 10.1016/j.imbio.2024.152783] [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: 08/19/2023] [Revised: 12/07/2023] [Accepted: 01/07/2024] [Indexed: 01/13/2024]
Abstract
BACKGROUND The origin recognition complex (ORC) consists of six subunits and mediates DNA replication by binding to its origin. Recent studies show that ORCs are closely related to various biological processes in tumors. However, a comprehensive study of ORCs in pan-cancer has not been conducted. RESULTS A systematic evaluation of the expression, mutation, and prognostic significance of ORCs was conducted across cancer types using data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases. The single-sample Gene Set Enrichment Analysis (ssGSEA) was performed using R package "Gene Set Variation Analysis (GSVA)" to evaluate ORC score. ORC score was significantly elevated in most cancers and linked with an inferior prognosis. It was positively related to the G2/M checkpoint and DNA repair pathways. An elevated ORC score also correlated with tumor mutation burden (TMB)/ microsatellite instability (MSI). A prognosis analysis suggested that high ORC scores were associated with heightened immunotherapeutic sensitivity. CONCLUSIONS Our research elucidates the genomic changes associated with and clinical relevance of ORCs in cancer and provides unique insights for future investigation of ORCs in immunotherapy.
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Affiliation(s)
- Yajun Zhao
- Department of Neurosurgery, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, China
| | - Jiangtao Wang
- Department of Neurosurgery, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, China
| | - Xiaodong Liang
- Department of Neurosurgery, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, China
| | - Chen Wang
- Department of Oncology, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, China.
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17
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Varon M, Dovrat D, Heuzé J, Tsirkas I, Singh SP, Pasero P, Galletto R, Aharoni A. Rrm3 and Pif1 division of labor during replication through leading and lagging strand G-quadruplex. Nucleic Acids Res 2024; 52:1753-1762. [PMID: 38117984 PMCID: PMC10899776 DOI: 10.1093/nar/gkad1205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 12/03/2023] [Accepted: 12/06/2023] [Indexed: 12/22/2023] Open
Abstract
Members of the conserved Pif1 family of 5'-3' DNA helicases can unwind G4s and mitigate their negative impact on genome stability. In Saccharomyces cerevisiae, two Pif1 family members, Pif1 and Rrm3, contribute to the suppression of genomic instability at diverse regions including telomeres, centromeres and tRNA genes. While Pif1 can resolve lagging strand G4s in vivo, little is known regarding Rrm3 function at G4s and its cooperation with Pif1 for G4 replication. Here, we monitored replication through G4 sequences in real time to show that Rrm3 is essential for efficient replisome progression through G4s located on the leading strand template, but not on the lagging strand. We found that Rrm3 importance for replication through G4s is dependent on its catalytic activity and its N-terminal unstructured region. Overall, we show that Rrm3 and Pif1 exhibit a division of labor that enables robust replication fork progression through leading and lagging strand G4s, respectively.
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Affiliation(s)
- Mor Varon
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
| | - Daniel Dovrat
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
| | - Jonathan Heuzé
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, 34396 Montpellier, France
| | - Ioannis Tsirkas
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
| | - Saurabh P Singh
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Philippe Pasero
- Institut de Génétique Humaine, CNRS, Université de Montpellier, Equipe Labellisée Ligue Contre le Cancer, 34396 Montpellier, France
| | - Roberto Galletto
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Amir Aharoni
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
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18
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Ahmad H, Chetlangia N, Prasanth SG. Chromatin's Influence on Pre-Replication Complex Assembly and Function. BIOLOGY 2024; 13:152. [PMID: 38534422 DOI: 10.3390/biology13030152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/19/2024] [Accepted: 02/19/2024] [Indexed: 03/28/2024]
Abstract
In all eukaryotes, the initiation of DNA replication requires a stepwise assembly of factors onto the origins of DNA replication. This is pioneered by the Origin Recognition Complex, which recruits Cdc6. Together, they bring Cdt1, which shepherds MCM2-7 to form the OCCM complex. Sequentially, a second Cdt1-bound hexamer of MCM2-7 is recruited by ORC-Cdc6 to form an MCM double hexamer, which forms a part of the pre-RC. Although the mechanism of ORC binding to DNA varies across eukaryotes, how ORC is recruited to replication origins in human cells remains an area of intense investigation. This review discusses how the chromatin environment influences pre-RC assembly, function, and, eventually, origin activity.
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Affiliation(s)
- Hina Ahmad
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801, USA
| | - Neha Chetlangia
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801, USA
| | - Supriya G Prasanth
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801, USA
- Cancer Center at Illinois, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
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19
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Yadav AK, Polasek-Sedlackova H. Quantity and quality of minichromosome maintenance protein complexes couple replication licensing to genome integrity. Commun Biol 2024; 7:167. [PMID: 38336851 PMCID: PMC10858283 DOI: 10.1038/s42003-024-05855-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
Accurate and complete replication of genetic information is a fundamental process of every cell division. The replication licensing is the first essential step that lays the foundation for error-free genome duplication. During licensing, minichromosome maintenance protein complexes, the molecular motors of DNA replication, are loaded to genomic sites called replication origins. The correct quantity and functioning of licensed origins are necessary to prevent genome instability associated with severe diseases, including cancer. Here, we delve into recent discoveries that shed light on the novel functions of licensed origins, the pathways necessary for their proper maintenance, and their implications for cancer therapies.
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Affiliation(s)
- Anoop Kumar Yadav
- Department of Cell Biology and Epigenetics, Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Hana Polasek-Sedlackova
- Department of Cell Biology and Epigenetics, Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic.
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20
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Foss EJ, Lichauco C, Gatbonton-Schwager T, Gonske SJ, Lofts B, Lao U, Bedalov A. Identification of 1600 replication origins in S. cerevisiae. eLife 2024; 12:RP88087. [PMID: 38315095 PMCID: PMC10945306 DOI: 10.7554/elife.88087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024] Open
Abstract
There are approximately 500 known origins of replication in the yeast genome, and the process by which DNA replication initiates at these locations is well understood. In particular, these sites are made competent to initiate replication by loading of the Mcm replicative helicase prior to the start of S phase; thus, 'a site that binds Mcm in G1' might be considered to provide an operational definition of a replication origin. By fusing a subunit of Mcm to micrococcal nuclease, we previously showed that known origins are typically bound by a single Mcm double hexamer, loaded adjacent to the ARS consensus sequence (ACS). Here, we extend this analysis from known origins to the entire genome, identifying candidate Mcm binding sites whose signal intensity varies over at least three orders of magnitude. Published data quantifying single-stranded DNA (ssDNA) during S phase revealed replication initiation among the most abundant 1600 of these sites, with replication activity decreasing with Mcm abundance and disappearing at the limit of detection of ssDNA. Three other hallmarks of replication origins were apparent among the most abundant 5500 sites. Specifically, these sites: (1) appeared in intergenic nucleosome-free regions flanked on one or both sides by well-positioned nucleosomes; (2) were flanked by ACSs; and (3) exhibited a pattern of GC skew characteristic of replication initiation. We conclude that, if sites at which Mcm double hexamers are loaded can function as replication origins, then DNA replication origins are at least threefold more abundant than previously assumed, and we suggest that replication may occasionally initiate in essentially every intergenic region. These results shed light on recent reports that as many as 15% of replication events initiate outside of known origins, and this broader distribution of replication origins suggest that S phase in yeast may be less distinct from that in humans than widely assumed.
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Affiliation(s)
- Eric J Foss
- Clinical Research Division, Fred Hutch Cancer CenterSeattleUnited States
| | - Carmina Lichauco
- Clinical Research Division, Fred Hutch Cancer CenterSeattleUnited States
| | | | - Sara J Gonske
- Clinical Research Division, Fred Hutch Cancer CenterSeattleUnited States
| | - Brandon Lofts
- Clinical Research Division, Fred Hutch Cancer CenterSeattleUnited States
| | - Uyen Lao
- Clinical Research Division, Fred Hutch Cancer CenterSeattleUnited States
| | - Antonio Bedalov
- Clinical Research Division, Fred Hutch Cancer CenterSeattleUnited States
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21
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Castellano CM, Lacroix L, Mathis E, Prorok P, Hennion M, Lopez-Rubio JJ, Méchali M, Gomes A. The genetic landscape of origins of replication in P. falciparum. Nucleic Acids Res 2024; 52:660-676. [PMID: 38038269 PMCID: PMC10810204 DOI: 10.1093/nar/gkad1103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 10/18/2023] [Accepted: 11/01/2023] [Indexed: 12/02/2023] Open
Abstract
Various origin mapping approaches have enabled genome-wide identification of origins of replication (ORI) in model organisms, but only a few studies have focused on divergent organisms. By employing three complementary approaches we provide a high-resolution map of ORIs in Plasmodium falciparum, the deadliest human malaria parasite. We profiled the distribution of origin of recognition complex (ORC) binding sites by ChIP-seq of two PfORC subunits and mapped active ORIs using NFS and SNS-seq. We show that ORIs lack sequence specificity but are not randomly distributed, and group in clusters. Licensing is biased towards regions of higher GC content and associated with G-quadruplex forming sequences (G4FS). While strong transcription likely enhances firing, active origins are depleted from transcription start sites. Instead, most accumulate in transcriptionally active gene bodies. Single molecule analysis of nanopore reads containing multiple initiation events, which could have only come from individual nuclei, showed a relationship between the replication fork pace and the distance to the nearest origin. While some similarities were drawn with the canonic eukaryote model, the distribution of ORIs in P. falciparum is likely shaped by unique genomic features such as extreme AT-richness-a product of evolutionary pressure imposed by the parasitic lifestyle.
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Affiliation(s)
| | - Laurent Lacroix
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Paris, France
| | - Emilie Mathis
- LPHI, CNRS, Université de Montpellier, 34095 Montpellier, France
| | - Paulina Prorok
- Institute of Human Genetics, CNRS, 34396 Montpellier, France
| | - Magali Hennion
- Université Paris Cité, CNRS, Epigenetics and Cell Fate, F-75013 Paris, France
| | | | - Marcel Méchali
- Institute of Human Genetics, CNRS, 34396 Montpellier, France
| | - Ana Rita Gomes
- LPHI, CNRS, Université de Montpellier, 34095 Montpellier, France
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22
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González-Acosta D, Lopes M. DNA replication and replication stress response in the context of nuclear architecture. Chromosoma 2024; 133:57-75. [PMID: 38055079 PMCID: PMC10904558 DOI: 10.1007/s00412-023-00813-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 12/07/2023]
Abstract
The DNA replication process needs to be coordinated with other DNA metabolism transactions and must eventually extend to the full genome, regardless of chromatin status, gene expression, secondary structures and DNA lesions. Completeness and accuracy of DNA replication are crucial to maintain genome integrity, limiting transformation in normal cells and offering targeting opportunities for proliferating cancer cells. DNA replication is thus tightly coordinated with chromatin dynamics and 3D genome architecture, and we are only beginning to understand the underlying molecular mechanisms. While much has recently been discovered on how DNA replication initiation is organised and modulated in different genomic regions and nuclear territories-the so-called "DNA replication program"-we know much less on how the elongation of ongoing replication forks and particularly the response to replication obstacles is affected by the local nuclear organisation. Also, it is still elusive how specific components of nuclear architecture participate in the replication stress response. Here, we review known mechanisms and factors orchestrating replication initiation, and replication fork progression upon stress, focusing on recent evidence linking genome organisation and nuclear architecture with the cellular responses to replication interference, and highlighting open questions and future challenges to explore this exciting new avenue of research.
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Affiliation(s)
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland.
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23
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Tye BK, Zhai Y. The Origin Recognition Complex: From Origin Selection to Replication Licensing in Yeast and Humans. BIOLOGY 2023; 13:13. [PMID: 38248444 PMCID: PMC10813338 DOI: 10.3390/biology13010013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/15/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024]
Abstract
Understanding human DNA replication through the study of yeast has been an extremely fruitful journey. The minichromosome maintenance (MCM) 2-7 genes that encode the catalytic core of the eukaryotic replisome were initially identified through forward yeast genetics. The origin recognition complexes (ORC) that load the MCM hexamers at replication origins were purified from yeast extracts. We have reached an age where high-resolution cryoEM structures of yeast and human replication complexes can be compared side-by-side. Their similarities and differences are converging as alternative strategies that may deviate in detail but are shared by both species.
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Affiliation(s)
- Bik-Kwoon Tye
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Yuanliang Zhai
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China;
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24
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Malzl D, Peycheva M, Rahjouei A, Gnan S, Klein KN, Nazarova M, Schoeberl UE, Gilbert DM, Buonomo SCB, Di Virgilio M, Neumann T, Pavri R. RIF1 regulates early replication timing in murine B cells. Nat Commun 2023; 14:8049. [PMID: 38081811 PMCID: PMC10713614 DOI: 10.1038/s41467-023-43778-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
The mammalian DNA replication timing (RT) program is crucial for the proper functioning and integrity of the genome. The best-known mechanism for controlling RT is the suppression of late origins of replication in heterochromatin by RIF1. Here, we report that in antigen-activated, hypermutating murine B lymphocytes, RIF1 binds predominantly to early-replicating active chromatin and promotes early replication, but plays a minor role in regulating replication origin activity, gene expression and genome organization in B cells. Furthermore, we find that RIF1 functions in a complementary and non-epistatic manner with minichromosome maintenance (MCM) proteins to establish early RT signatures genome-wide and, specifically, to ensure the early replication of highly transcribed genes. These findings reveal additional layers of regulation within the B cell RT program, driven by the coordinated activity of RIF1 and MCM proteins.
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Affiliation(s)
- Daniel Malzl
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter, 1030, Vienna, Austria
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090, Lazarettgasse 14, Vienna, Austria
| | - Mihaela Peycheva
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter, 1030, Vienna, Austria
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090, Lazarettgasse 14, Vienna, Austria
| | - Ali Rahjouei
- Max-Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Stefano Gnan
- School of Biological Sciences, Institute of Cell Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Kyle N Klein
- San Diego Biomedical Research Institute, San Diego, CA, 92121, USA
| | - Mariia Nazarova
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter, 1030, Vienna, Austria
| | - Ursula E Schoeberl
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter, 1030, Vienna, Austria
| | - David M Gilbert
- San Diego Biomedical Research Institute, San Diego, CA, 92121, USA
| | - Sara C B Buonomo
- School of Biological Sciences, Institute of Cell Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Michela Di Virgilio
- Max-Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Tobias Neumann
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter, 1030, Vienna, Austria.
- Quantro Therapeutics, Vienna Biocenter, 1030, Vienna, Austria.
| | - Rushad Pavri
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter, 1030, Vienna, Austria.
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25
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Lebdy R, Canut M, Patouillard J, Cadoret JC, Letessier A, Ammar J, Basbous J, Urbach S, Miotto B, Constantinou A, Abou Merhi R, Ribeyre C. The nucleolar protein GNL3 prevents resection of stalled replication forks. EMBO Rep 2023; 24:e57585. [PMID: 37965896 DOI: 10.15252/embr.202357585] [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: 06/02/2023] [Revised: 10/25/2023] [Accepted: 10/27/2023] [Indexed: 11/16/2023] Open
Abstract
Faithful DNA replication requires specific proteins that protect replication forks and so prevent the formation of DNA lesions that may damage the genome. Identification of new proteins involved in this process is essential to understand how DNA lesions accumulate in cancer cells and how they tolerate them. Here, we show that human GNL3/nucleostemin, a GTP-binding protein localized mostly in the nucleolus and highly expressed in cancer cells, prevents nuclease-dependent resection of nascent DNA in response to replication stress. We demonstrate that inhibiting origin firing reduces resection. This suggests that the heightened replication origin activation observed upon GNL3 depletion largely drives the observed DNA resection probably due to the exhaustion of the available RPA pool. We show that GNL3 and DNA replication initiation factor ORC2 interact in the nucleolus and that the concentration of GNL3 in the nucleolus is required to limit DNA resection. We propose that the control of origin firing by GNL3 through the sequestration of ORC2 in the nucleolus is critical to prevent nascent DNA resection in response to replication stress.
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Affiliation(s)
- Rana Lebdy
- Institut de Génétique Humaine (UMR9002), CNRS, Université de Montpellier, Montpellier Cedex 5, France
- Faculty of Sciences, Genomics and Surveillance Biotherapy (GSBT) Laboratory, R. Hariri Campus, Lebanese University, Hadath, Lebanon
| | - Marine Canut
- Institut de Génétique Humaine (UMR9002), CNRS, Université de Montpellier, Montpellier Cedex 5, France
| | - Julie Patouillard
- Institut de Génétique Humaine (UMR9002), CNRS, Université de Montpellier, Montpellier Cedex 5, France
| | | | - Anne Letessier
- Université Paris Cité, Institut Cochin, INSERM, CNRS, Paris, France
| | - Josiane Ammar
- Institut de Génétique Humaine (UMR9002), CNRS, Université de Montpellier, Montpellier Cedex 5, France
| | - Jihane Basbous
- Institut de Génétique Humaine (UMR9002), CNRS, Université de Montpellier, Montpellier Cedex 5, France
| | - Serge Urbach
- Institut de Génomique Fonctionnelle, CNRS UMR 5203, Inserm U1191, Université de Montpellier, Montpellier Cedex 5, France
| | - Benoit Miotto
- Université Paris Cité, Institut Cochin, INSERM, CNRS, Paris, France
| | - Angelos Constantinou
- Institut de Génétique Humaine (UMR9002), CNRS, Université de Montpellier, Montpellier Cedex 5, France
| | - Raghida Abou Merhi
- Faculty of Sciences, Genomics and Surveillance Biotherapy (GSBT) Laboratory, R. Hariri Campus, Lebanese University, Hadath, Lebanon
| | - Cyril Ribeyre
- Institut de Génétique Humaine (UMR9002), CNRS, Université de Montpellier, Montpellier Cedex 5, France
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26
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Chen N, Buonomo SCB. Three-dimensional nuclear organisation and the DNA replication timing program. Curr Opin Struct Biol 2023; 83:102704. [PMID: 37741142 DOI: 10.1016/j.sbi.2023.102704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/26/2023] [Accepted: 08/23/2023] [Indexed: 09/25/2023]
Abstract
In eukaryotic cells, genome duplication is temporally organised according to a program referred to as the replication-timing (RT) program. The RT of individual genomic domains strikingly parallels the three-dimensional architecture of their chromatin contacts and subnuclear distribution. However, it is unclear whether this correspondence is coincidental or whether it indicates a causal and regulatory relationship. In either case, the nature of the molecular mechanisms ensuring this spatio-temporal coordination is still unknown. Here, we review recent evidence that begins to uncover the existence of a shared molecular machinery at the core of the spatio-temporal co-regulation of DNA replication and genome architecture. Finally, we discuss the outstanding, key question of the biological role of their coordination.
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Affiliation(s)
- Naiming Chen
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Roger Land Building, Alexander Crum Brown Road, Edinburgh, EH9 3FF, UK
| | - Sara C B Buonomo
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Roger Land Building, Alexander Crum Brown Road, Edinburgh, EH9 3FF, UK.
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27
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Tian M, Wang Z, Su Z, Shibata E, Shibata Y, Dutta A, Zang C. Integrative analysis of DNA replication origins and ORC/MCM binding sites in human cells reveals a lack of overlap. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.25.550556. [PMID: 37546918 PMCID: PMC10402023 DOI: 10.1101/2023.07.25.550556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Based on experimentally determined average inter-origin distances of ∼100 kb, DNA replication initiates from ∼50,000 origins on human chromosomes in each cell cycle. The origins are believed to be specified by binding of factors like the Origin Recognition Complex (ORC) or CTCF or other features like G-quadruplexes. We have performed an integrative analysis of 113 genome-wide human origin profiles (from five different techniques) and 5 ORC-binding profiles to critically evaluate whether the most reproducible origins are specified by these features. Out of ∼7.5 million union origins identified by all datasets, only 0.27% were reproducibly obtained in at least 20 independent SNS-seq datasets and contained in initiation zones identified by each of three other techniques (20,250 shared origins), suggesting extensive variability in origin usage and identification. 21% of the shared origins overlap with transcriptional promoters, posing a conundrum. Although the shared origins overlap more than union origins with constitutive CTCF binding sites, G-quadruplex sites and activating histone marks, these overlaps are comparable or less than that of known Transcription Start Sites, so that these features could be enriched in origins because of the overlap of origins with epigenetically open, promoter-like sequences. Only 6.4% of the 20,250 shared origins were within 1 kb from any of the ∼13,000 reproducible ORC binding sites in human cancer cells, and only 4.5% were within 1 kb of the ∼11,000 union MCM2-7 binding sites in contrast to the nearly 100% overlap in the two comparisons in the yeast, S. cerevisiae . Thus, in human cancer cell lines, replication origins appear to be specified by highly variable stochastic events dependent on the high epigenetic accessibility around promoters, without extensive overlap between the most reproducible origins and currently known ORC- or MCM-binding sites.
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28
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Foss EJ, Lichauco C, Gatbonton-Schwager T, Gonske SJ, Lofts B, Lao U, Bedalov A. Identification of 1600 replication origins in S. cerevisiae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.11.536402. [PMID: 38014147 PMCID: PMC10680564 DOI: 10.1101/2023.04.11.536402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
There are approximately 500 known origins of replication in the yeast genome, and the process by which DNA replication initiates at these locations is well understood. In particular, these sites are made competent to initiate replication by loading of the Mcm replicative helicase prior to the start of S phase; thus, "a site to which MCM is bound in G1" might be considered to provide an operational definition of a replication origin. By fusing a subunit of Mcm to micrococcal nuclease, a technique referred to as "Chromatin Endogenous Cleavage", we previously showed that known origins are typically bound by a single Mcm double hexamer, loaded adjacent to the ARS consensus sequence (ACS). Here we extend this analysis from known origins to the entire genome, identifying candidate Mcm binding sites whose signal intensity varies over at least 3 orders of magnitude. Published data quantifying the production of ssDNA during S phase showed clear evidence of replication initiation among the most abundant 1600 of these sites, with replication activity decreasing in concert with Mcm abundance and disappearing at the limit of detection of ssDNA. Three other hallmarks of replication origins were apparent among the most abundant 5,500 sites. Specifically, these sites (1) appeared in intergenic nucleosome-free regions that were flanked on one or both sides by well-positioned nucleosomes; (2) were flanked by ACSs; and (3) exhibited a pattern of GC skew characteristic of replication initiation. Furthermore, the high resolution of this technique allowed us to demonstrate a strong bias for detecting Mcm double-hexamers downstream rather than upstream of the ACS, which is consistent with the directionality of Mcm loading by Orc that has been observed in vitro. We conclude that, if sites at which Mcm double-hexamers are loaded can function as replication origins, then DNA replication origins are at least 3-fold more abundant than previously assumed, and we suggest that replication may occasionally initiate in essentially every intergenic region. These results shed light on recent reports that as many as 15% of replication events initiate outside of known origins, and this broader distribution of replication origins suggest that S phase in yeast may be less distinct from that in humans than is widely assumed.
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Affiliation(s)
- Eric J Foss
- Clinical Research Division, Fred Hutch Cancer Center, Seattle, WA 98109
| | - Carmina Lichauco
- Clinical Research Division, Fred Hutch Cancer Center, Seattle, WA 98109
| | | | - Sara J Gonske
- Clinical Research Division, Fred Hutch Cancer Center, Seattle, WA 98109
| | - Brandon Lofts
- Clinical Research Division, Fred Hutch Cancer Center, Seattle, WA 98109
| | - Uyen Lao
- Clinical Research Division, Fred Hutch Cancer Center, Seattle, WA 98109
| | - Antonio Bedalov
- Clinical Research Division, Fred Hutch Cancer Center, Seattle, WA 98109
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29
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Bellani MA, Shaik A, Majumdar I, Ling C, Seidman MM. The Response of the Replication Apparatus to Leading Template Strand Blocks. Cells 2023; 12:2607. [PMID: 37998342 PMCID: PMC10670059 DOI: 10.3390/cells12222607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 11/25/2023] Open
Abstract
Duplication of the genome requires the replication apparatus to overcome a variety of impediments, including covalent DNA adducts, the most challenging of which is on the leading template strand. Replisomes consist of two functional units, a helicase to unwind DNA and polymerases to synthesize it. The helicase is a multi-protein complex that encircles the leading template strand and makes the first contact with a leading strand adduct. The size of the channel in the helicase would appear to preclude transit by large adducts such as DNA: protein complexes (DPC). Here we discuss some of the extensively studied pathways that support replication restart after replisome encounters with leading template strand adducts. We also call attention to recent work that highlights the tolerance of the helicase for adducts ostensibly too large to pass through the central channel.
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Affiliation(s)
| | | | | | | | - Michael M. Seidman
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA; (M.A.B.)
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30
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Wegrzyn K, Oliwa M, Nowacka M, Zabrocka E, Bury K, Purzycki P, Czaplewska P, Pipka J, Giraldo R, Konieczny I. Rep protein accommodates together dsDNA and ssDNA which enables a loop-back mechanism to plasmid DNA replication initiation. Nucleic Acids Res 2023; 51:10551-10567. [PMID: 37713613 PMCID: PMC10602881 DOI: 10.1093/nar/gkad740] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 08/25/2023] [Accepted: 09/08/2023] [Indexed: 09/17/2023] Open
Abstract
For DNA replication initiation in Bacteria, replication initiation proteins bind to double-stranded DNA (dsDNA) and interact with single-stranded DNA (ssDNA) at the replication origin. The structural-functional relationship of the nucleoprotein complex involving initiator proteins is still elusive and different models are proposed. In this work, based on crosslinking combined with mass spectrometry (MS), the analysis of mutant proteins and crystal structures, we defined amino acid residues essential for the interaction between plasmid Rep proteins, TrfA and RepE, and ssDNA. This interaction and Rep binding to dsDNA could not be provided in trans, and both are important for dsDNA melting at DNA unwinding element (DUE). We solved two crystal structures of RepE: one in a complex with ssDNA DUE, and another with both ssDNA DUE and dsDNA containing RepE-specific binding sites (iterons). The amino acid residues involved in interaction with ssDNA are located in the WH1 domain in stand β1, helices α1 and α2 and in the WH2 domain in loops preceding strands β1' and β2' and in these strands. It is on the opposite side compared to RepE dsDNA-recognition interface. Our data provide evidence for a loop-back mechanism through which the plasmid replication initiator molecule accommodates together dsDNA and ssDNA.
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Affiliation(s)
- Katarzyna Wegrzyn
- Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - Monika Oliwa
- Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - Marzena Nowacka
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology in Warsaw, Księcia Trojdena 4, 02-109 Warsaw, Poland
| | - Elżbieta Zabrocka
- Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - Katarzyna Bury
- Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - Piotr Purzycki
- Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - Paulina Czaplewska
- Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - Justyna Pipka
- Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - Rafael Giraldo
- Centro de Investigaciones Biológicas – CSIC, E28040 Madrid, Spain
| | - Igor Konieczny
- Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
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31
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Sahu S, Ekundayo BE, Kumar A, Bleichert F. A dual role for the chromatin reader ORCA/LRWD1 in targeting the origin recognition complex to chromatin. EMBO J 2023; 42:e114654. [PMID: 37551430 PMCID: PMC10505921 DOI: 10.15252/embj.2023114654] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 08/09/2023] Open
Abstract
Eukaryotic cells use chromatin marks to regulate the initiation of DNA replication. The origin recognition complex (ORC)-associated protein ORCA plays a critical role in heterochromatin replication in mammalian cells by recruiting the initiator ORC, but the underlying mechanisms remain unclear. Here, we report crystal and cryo-electron microscopy structures of ORCA in complex with ORC's Orc2 subunit and nucleosomes, establishing that ORCA orchestrates ternary complex assembly by simultaneously recognizing a highly conserved peptide sequence in Orc2, nucleosomal DNA, and repressive histone trimethylation marks through an aromatic cage. Unexpectedly, binding of ORCA to nucleosomes prevents chromatin array compaction in a manner that relies on H4K20 trimethylation, a histone modification critical for heterochromatin replication. We further show that ORCA is necessary and sufficient to specifically recruit ORC into chromatin condensates marked by H4K20 trimethylation, providing a paradigm for studying replication initiation in specific chromatin contexts. Collectively, our findings support a model in which ORCA not only serves as a platform for ORC recruitment to nucleosomes bearing specific histone marks but also helps establish a local chromatin environment conducive to subsequent MCM2-7 loading.
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Affiliation(s)
- Sumon Sahu
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenCTUSA
| | - Babatunde E Ekundayo
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenCTUSA
- Present address:
Laboratory of Biological Electron MicroscopyEPFLLausanneSwitzerland
| | - Ashish Kumar
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenCTUSA
| | - Franziska Bleichert
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenCTUSA
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32
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Haccard O, Ciardo D, Narrissamprakash H, Bronchain O, Kumagai A, Dunphy WG, Goldar A, Marheineke K. Rif1 restrains the rate of replication origin firing in Xenopus laevis. Commun Biol 2023; 6:788. [PMID: 37516798 PMCID: PMC10387115 DOI: 10.1038/s42003-023-05172-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 07/24/2023] [Indexed: 07/31/2023] Open
Abstract
Metazoan genomes are duplicated by the coordinated activation of clusters of replication origins at different times during S phase, but the underlying mechanisms of this temporal program remain unclear during early development. Rif1, a key replication timing factor, inhibits origin firing by recruiting protein phosphatase 1 (PP1) to chromatin counteracting S phase kinases. We have previously described that Rif1 depletion accelerates early Xenopus laevis embryonic cell cycles. Here, we find that in the absence of Rif1, patterns of replication foci change along with the acceleration of replication cluster activation. However, initiations increase only moderately inside active clusters. Our numerical simulations suggest that the absence of Rif1 compresses the temporal program towards more homogeneity and increases the availability of limiting initiation factors. We experimentally demonstrate that Rif1 depletion increases the chromatin-binding of the S phase kinase Cdc7/Drf1, the firing factors Treslin, MTBP, Cdc45, RecQL4, and the phosphorylation of both Treslin and MTBP. We show that Rif1 globally, but not locally, restrains the replication program in early embryos, possibly by inhibiting or excluding replication factors from chromatin.
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Affiliation(s)
- Olivier Haccard
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Diletta Ciardo
- Institut de Biologie de l'Ecole Normale Supérieure, Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Hemalatha Narrissamprakash
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Odile Bronchain
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, CERTO-Retina France, 91400, Saclay, France
| | - Akiko Kumagai
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - William G Dunphy
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Arach Goldar
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Kathrin Marheineke
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
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33
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Varshavsky A, Lewis K, Chen SJ. Deletions of DNA in cancer and their possible uses for therapy. Bioessays 2023; 45:e2300051. [PMID: 37166062 PMCID: PMC11102808 DOI: 10.1002/bies.202300051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 04/09/2023] [Accepted: 04/12/2023] [Indexed: 05/12/2023]
Abstract
Despite advances in treatments over the last decades, a uniformly reliable and free of side effects therapy of human cancers remains to be achieved. During chromosome replication, a premature halt of two converging DNA replication forks would cause incomplete replication and a cytotoxic chromosome nondisjunction during mitosis. In contrast to normal cells, most cancer cells bear numerous DNA deletions. A homozygous deletion permanently marks a cell and its descendants. Here, we propose an approach to cancer therapy in which a pair of sequence-specific roadblocks is placed solely at two cancer-confined deletion sites that are located ahead of two converging replication forks. We describe this method, termed "replication blocks specific for deletions" (RBSD), and another deletions-based approach as well. RBSD can be expanded by placing pairs of replication roadblocks on several different chromosomes. The resulting simultaneous nondisjunctions of these chromosomes in cancer cells would further increase the cancer-specific toxicity of RBSD.
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Affiliation(s)
- Alexander Varshavsky
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Kim Lewis
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Shun-Jia Chen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
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34
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Nasheuer HP, Onwubiko NO. Lagging Strand Initiation Processes in DNA Replication of Eukaryotes-Strings of Highly Coordinated Reactions Governed by Multiprotein Complexes. Genes (Basel) 2023; 14:genes14051012. [PMID: 37239371 DOI: 10.3390/genes14051012] [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: 04/06/2023] [Revised: 04/27/2023] [Accepted: 04/28/2023] [Indexed: 05/28/2023] Open
Abstract
In their influential reviews, Hanahan and Weinberg coined the term 'Hallmarks of Cancer' and described genome instability as a property of cells enabling cancer development. Accurate DNA replication of genomes is central to diminishing genome instability. Here, the understanding of the initiation of DNA synthesis in origins of DNA replication to start leading strand synthesis and the initiation of Okazaki fragment on the lagging strand are crucial to control genome instability. Recent findings have provided new insights into the mechanism of the remodelling of the prime initiation enzyme, DNA polymerase α-primase (Pol-prim), during primer synthesis, how the enzyme complex achieves lagging strand synthesis, and how it is linked to replication forks to achieve optimal initiation of Okazaki fragments. Moreover, the central roles of RNA primer synthesis by Pol-prim in multiple genome stability pathways such as replication fork restart and protection of DNA against degradation by exonucleases during double-strand break repair are discussed.
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Affiliation(s)
- Heinz Peter Nasheuer
- Centre for Chromosome Biology, Arts & Science Building, Main Concourse, School of Biological and Chemical Sciences, Biochemistry, University of Galway, Distillery Road, H91 TK33 Galway, Ireland
| | - Nichodemus O Onwubiko
- Centre for Chromosome Biology, Arts & Science Building, Main Concourse, School of Biological and Chemical Sciences, Biochemistry, University of Galway, Distillery Road, H91 TK33 Galway, Ireland
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35
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Gilbert DM. Replication licensing during S phase: breaking the law to prevent breaking DNA. Nat Struct Mol Biol 2023; 30:406-408. [PMID: 37041325 DOI: 10.1038/s41594-023-00962-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Affiliation(s)
- David M Gilbert
- Laboratory of Chromosome Replication and Epigenome Regulation, San Diego Biomedical Research Institute, San Diego, CA, USA.
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36
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Brison O, Gnan S, Azar D, Koundrioukoff S, Melendez-Garcia R, Kim SJ, Schmidt M, El-Hilali S, Jaszczyszyn Y, Lachages AM, Thermes C, Chen CL, Debatisse M. Mistimed origin licensing and activation stabilize common fragile sites under tight DNA-replication checkpoint activation. Nat Struct Mol Biol 2023; 30:539-550. [PMID: 37024657 DOI: 10.1038/s41594-023-00949-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 02/28/2023] [Indexed: 04/08/2023]
Abstract
Genome integrity requires replication to be completed before chromosome segregation. The DNA-replication checkpoint (DRC) contributes to this coordination by inhibiting CDK1, which delays mitotic onset. Under-replication of common fragile sites (CFSs), however, escapes surveillance, resulting in mitotic chromosome breaks. Here we asked whether loose DRC activation induced by modest stresses commonly used to destabilize CFSs could explain this leakage. We found that tightening DRC activation or CDK1 inhibition stabilizes CFSs in human cells. Repli-Seq and molecular combing analyses showed a burst of replication initiations implemented in mid S-phase across a subset of late-replicating sequences, including CFSs, while the bulk genome was unaffected. CFS rescue and extra-initiations required CDC6 and CDT1 availability in S-phase, implying that CDK1 inhibition permits mistimed origin licensing and firing. In addition to delaying mitotic onset, tight DRC activation therefore supports replication completion of late origin-poor domains at risk of under-replication, two complementary roles preserving genome stability.
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Affiliation(s)
- Olivier Brison
- CNRS UMR 9019, Gustave Roussy Institute, Villejuif, France
- Paris-Saclay University, Gif-sur-Yvette, France
| | - Stefano Gnan
- Curie Institute, PSL Research University, CNRS UMR 3244, Paris, France
- Sorbonne University, Paris, France
| | - Dana Azar
- Curie Institute, PSL Research University, CNRS UMR 3244, Paris, France
- Sorbonne University, Paris, France
- Laboratoire Biodiversité et Génomique Fonctionnelle, Faculté des Sciences, Université Saint-Joseph, Beirut, Lebanon
| | - Stéphane Koundrioukoff
- CNRS UMR 9019, Gustave Roussy Institute, Villejuif, France
- Sorbonne University, Paris, France
| | - Rodrigo Melendez-Garcia
- CNRS UMR 9019, Gustave Roussy Institute, Villejuif, France
- Paris-Saclay University, Gif-sur-Yvette, France
| | - Su-Jung Kim
- CNRS UMR 9019, Gustave Roussy Institute, Villejuif, France
- Paris-Saclay University, Gif-sur-Yvette, France
| | - Mélanie Schmidt
- CNRS UMR 9019, Gustave Roussy Institute, Villejuif, France
- Paris-Saclay University, Gif-sur-Yvette, France
| | - Sami El-Hilali
- Curie Institute, PSL Research University, CNRS UMR 3244, Paris, France
- Sorbonne University, Paris, France
- Villefranche sur mer Developmental Biology Laboratory, CNRS UMR7009, Villefranche-sur-Mer, France
| | - Yan Jaszczyszyn
- Paris-Saclay University, Gif-sur-Yvette, France
- Institute for Integrative Biology of the Cell (I2BC), UMR 9198CNRS, CEA, Paris-Sud University, Gif-sur-Yvette, France
| | - Anne-Marie Lachages
- Curie Institute, PSL Research University, CNRS UMR 3244, Paris, France
- UTCBS, CNRS UMR 8258/ INSERM U 1267, Sorbonne-Paris-Cité University, Paris, France
| | - Claude Thermes
- Paris-Saclay University, Gif-sur-Yvette, France
- Institute for Integrative Biology of the Cell (I2BC), UMR 9198CNRS, CEA, Paris-Sud University, Gif-sur-Yvette, France
| | - Chun-Long Chen
- Curie Institute, PSL Research University, CNRS UMR 3244, Paris, France
- Sorbonne University, Paris, France
| | - Michelle Debatisse
- CNRS UMR 9019, Gustave Roussy Institute, Villejuif, France.
- Sorbonne University, Paris, France.
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