1
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Berger S, Chistol G. Visualizing the dynamics of DNA replication and repair at the single-molecule level. Methods Cell Biol 2023; 182:109-165. [PMID: 38359974 PMCID: PMC11246157 DOI: 10.1016/bs.mcb.2023.07.001] [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: 02/17/2024]
Abstract
During cell division, the genome of each eukaryotic cell is copied by thousands of replisomes-large protein complexes consisting of several dozen proteins. Recent studies suggest that the eukaryotic replisome is much more dynamic than previously thought. To directly visualize replisome dynamics in a physiological context, we recently developed a single-molecule approach for imaging replication proteins in Xenopus egg extracts. These extracts contain all the soluble nuclear proteins and faithfully recapitulate DNA replication and repair in vitro, serving as a powerful platform for studying the mechanisms of genome maintenance. Here we present detailed protocols for conducting single-molecule experiments in nuclear egg extracts and preparing key reagents. This workflow can be easily adapted to visualize the dynamics and function of other proteins implicated in DNA replication and repair.
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Affiliation(s)
- Scott Berger
- Biophysics Program, Stanford School of Medicine, Stanford, CA, United States
| | - Gheorghe Chistol
- Biophysics Program, Stanford School of Medicine, Stanford, CA, United States; Chemical and Systems Biology Department, Cancer Biology Program, Stanford School of Medicine, Stanford, CA, United States.
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2
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Williams KS, Secomb TW, El-Kareh AW. An autonomous mathematical model for the mammalian cell cycle. J Theor Biol 2023; 569:111533. [PMID: 37196820 DOI: 10.1016/j.jtbi.2023.111533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 04/04/2023] [Accepted: 05/10/2023] [Indexed: 05/19/2023]
Abstract
A mathematical model for the mammalian cell cycle is developed as a system of 13 coupled nonlinear ordinary differential equations. The variables and interactions included in the model are based on detailed consideration of available experimental data. A novel feature of the model is inclusion of cycle tasks such as origin licensing and initiation, nuclear envelope breakdown and kinetochore attachment, and their interactions with controllers (molecular complexes involved in cycle control). Other key features are that the model is autonomous, except for a dependence on external growth factors; the variables are continuous in time, without instantaneous resets at phase boundaries; mechanisms to prevent rereplication are included; and cycle progression is independent of cell size. Eight variables represent cell cycle controllers: the Cyclin D1-Cdk4/6 complex, APCCdh1, SCFβTrCP, Cdc25A, MPF, NuMA, the securin-separase complex, and separase. Five variables represent task completion, with four for the status of origins and one for kinetochore attachment. The model predicts distinct behaviors corresponding to the main phases of the cell cycle, showing that the principal features of the mammalian cell cycle, including restriction point behavior, can be accounted for in a quantitative mechanistic way based on known interactions among cycle controllers and their coupling to tasks. The model is robust to parameter changes, in that cycling is maintained over at least a five-fold range of each parameter when varied individually. The model is suitable for exploring how extracellular factors affect cell cycle progression, including responses to metabolic conditions and to anti-cancer therapies.
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Affiliation(s)
| | - Timothy W Secomb
- BIO5 Institute, University of Arizona, Tucson, AZ, USA; Department of Physiology, University of Arizona, Tucson, AZ, USA
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3
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Amin A, Wu R, Khan MA, Cheung MH, Liang Y, Liu C, Zhu G, Yu ZL, Liang C. An essential Noc3p dimerization cycle mediates ORC double-hexamer formation in replication licensing. Life Sci Alliance 2023; 6:e202201594. [PMID: 36599624 PMCID: PMC9813392 DOI: 10.26508/lsa.202201594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 12/17/2022] [Accepted: 12/19/2022] [Indexed: 01/05/2023] Open
Abstract
Replication licensing, a prerequisite of DNA replication, helps to ensure once-per-cell-cycle genome duplication. Some DNA replication-initiation proteins are sequentially loaded onto replication origins to form pre-replicative complexes (pre-RCs). ORC and Noc3p bind replication origins throughout the cell cycle, providing a platform for pre-RC assembly. We previously reported that cell cycle-dependent ORC dimerization is essential for the chromatin loading of the symmetric MCM double-hexamers. Here, we used Saccharomyces cerevisiae separation-of-function NOC3 mutants to confirm the separable roles of Noc3p in DNA replication and ribosome biogenesis. We also show that an essential and cell cycle-dependent Noc3p dimerization cycle regulates the ORC dimerization cycle. Noc3p dimerizes at the M-to-G1 transition and de-dimerizes in S-phase. The Noc3p dimerization cycle coupled with the ORC dimerization cycle enables replication licensing, protects nascent sister replication origins after replication initiation, and prevents re-replication. This study has revealed a new mechanism of replication licensing and elucidated the molecular mechanism of Noc3p as a mediator of ORC dimerization in pre-RC formation.
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Affiliation(s)
- Aftab Amin
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China
| | - Rentian Wu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Muhammad Ajmal Khan
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Man Hei Cheung
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Yanting Liang
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Changdong Liu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Guang Zhu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Zhi-Ling Yu
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China
| | - Chun Liang
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
- EnKang Pharmaceuticals (Guangzhou), Ltd., Guangzhou, China
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4
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Ng LY, Ma HT, Poon RYC. Cyclin A-CDK1 suppresses the expression of the CDK1 activator CDC25A to safeguard timely mitotic entry. J Biol Chem 2023; 299:102957. [PMID: 36717077 PMCID: PMC9986519 DOI: 10.1016/j.jbc.2023.102957] [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: 11/23/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 01/29/2023] Open
Abstract
Cyclin A and CDC25A are both activators of cyclin-dependent kinases (CDKs): cyclin A acts as an activating subunit of CDKs and CDC25A a phosphatase of the inhibitory phosphorylation sites of the CDKs. In this study, we uncovered an inverse relationship between the two CDK activators. As cyclin A is an essential gene, we generated a conditional silencing cell line using a combination of CRISPR-Cas9 and degron-tagged cyclin A. Destruction of cyclin A promoted an acute accumulation of CDC25A. The increase of CDC25A after cyclin A depletion occurred throughout the cell cycle and was independent on cell cycle delay caused by cyclin A deficiency. Moreover, we determined that the inverse relationship with cyclin A was specific for CDC25A and not for other CDC25 family members or kinases that regulate the same sites in CDKs. Unexpectedly, the upregulation of CDC25A was mainly caused by an increase in transcriptional activity instead of a change in the stability of the protein. Reversing the accumulation of CDC25A severely delayed G2-M in cyclin A-depleted cells. Taken together, these data provide evidence of a compensatory mechanism involving CDC25A that ensures timely mitotic entry at different levels of cyclin A.
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Affiliation(s)
- Lau Yan Ng
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Hoi Tang Ma
- Department of Pathology, The University of Hong Kong, Hong Kong, China; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong, China
| | - Randy Y C Poon
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China; State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China.
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5
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Ratnayeke N, Baris Y, Chung M, Yeeles JTP, Meyer T. CDT1 inhibits CMG helicase in early S phase to separate origin licensing from DNA synthesis. Mol Cell 2023; 83:26-42.e13. [PMID: 36608667 DOI: 10.1016/j.molcel.2022.12.004] [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: 07/12/2022] [Revised: 09/16/2022] [Accepted: 12/08/2022] [Indexed: 01/07/2023]
Abstract
Human cells license tens of thousands of origins of replication in G1 and then must stop all licensing before DNA synthesis in S phase to prevent re-replication and genome instability that ensue when an origin is licensed on replicated DNA. However, the E3 ubiquitin ligase CRL4Cdt2 only starts to degrade the licensing factor CDT1 after origin firing, raising the question of how cells prevent re-replication before CDT1 is fully degraded. Here, using quantitative microscopy and in-vitro-reconstituted human DNA replication, we show that CDT1 inhibits DNA synthesis during an overlap period when CDT1 is still present after origin firing. CDT1 inhibits DNA synthesis by suppressing CMG helicase at replication forks, and DNA synthesis commences once CDT1 is degraded. Thus, in contrast to the prevailing model that human cells prevent re-replication by strictly separating licensing from firing, licensing and firing overlap, and cells instead separate licensing from DNA synthesis.
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Affiliation(s)
- Nalin Ratnayeke
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Cell and Developmental Biology, Weill Cornell Medical College, New York, NY 10065, USA
| | - Yasemin Baris
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | - Mingyu Chung
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Joseph T P Yeeles
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
| | - Tobias Meyer
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Cell and Developmental Biology, Weill Cornell Medical College, New York, NY 10065, USA.
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6
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Stępień K, Skoneczna A, Kula-Maximenko M, Jurczyk Ł, Mołoń M. Depletion of the Origin Recognition Complex Subunits Delays Aging in Budding Yeast. Cells 2022; 11:cells11081252. [PMID: 35455932 PMCID: PMC9032818 DOI: 10.3390/cells11081252] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/31/2022] [Accepted: 04/05/2022] [Indexed: 12/01/2022] Open
Abstract
Precise DNA replication is pivotal for ensuring the accurate inheritance of genetic information. To avoid genetic instability, each DNA fragment needs to be amplified only once per cell cycle. DNA replication in eukaryotes starts with the binding of the origin recognition complex (ORC) to the origins of DNA replication. The genes encoding ORC subunits have been conserved across eukaryotic evolution and are essential for the initiation of DNA replication. In this study, we conducted an extensive physiological and aging-dependent analysis of heterozygous cells lacking one copy of ORC genes in the BY4743 background. Cells with only one copy of the ORC genes showed a significant decrease in the level of ORC mRNA, a delay in the G1 phase of the cell cycle, and an extended doubling time. Here, we also show that the reducing the levels of Orc1-6 proteins significantly extends both the budding and average chronological lifespans. Heterozygous ORC/orcΔ and wild-type diploid cells easily undergo haploidization during chronological aging. This ploidy shift might be related to nutrient starvation or the inability to survive under stress conditions. A Raman spectroscopy analysis helped us to strengthen the hypothesis of the importance of lipid metabolism and homeostasis in aging.
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Affiliation(s)
- Karolina Stępień
- Department of Biology, Institute of Biology and Biotechnology, University of Rzeszów, 35-601 Rzeszów, Poland;
| | - Adrianna Skoneczna
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Correspondence: (A.S.); (M.M.); Tel.: +48-22-659-70-72 (A.S.); +48-17-785-54-07 (M.M.)
| | - Monika Kula-Maximenko
- The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, 30-239 Krakow, Poland;
| | - Łukasz Jurczyk
- Institute of Agricultural Sciences, Land Management and Environmental Protection, University of Rzeszow, 35-601 Rzeszów, Poland;
| | - Mateusz Mołoń
- Department of Biology, Institute of Biology and Biotechnology, University of Rzeszów, 35-601 Rzeszów, Poland;
- Correspondence: (A.S.); (M.M.); Tel.: +48-22-659-70-72 (A.S.); +48-17-785-54-07 (M.M.)
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7
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Targeted inhibition of the expression of both MCM5 and MCM7 by miRNA-214 impedes DNA replication and tumorigenesis in hepatocellular carcinoma cells. Cancer Lett 2022; 539:215677. [DOI: 10.1016/j.canlet.2022.215677] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/12/2022] [Accepted: 03/29/2022] [Indexed: 12/12/2022]
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8
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Schmidt JM, Yang R, Kumar A, Hunker O, Seebacher J, Bleichert F. A mechanism of origin licensing control through autoinhibition of S. cerevisiae ORC·DNA·Cdc6. Nat Commun 2022; 13:1059. [PMID: 35217664 PMCID: PMC8881611 DOI: 10.1038/s41467-022-28695-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 02/04/2022] [Indexed: 11/10/2022] Open
Abstract
The coordinated action of multiple replicative helicase loading factors is needed for the licensing of replication origins prior to DNA replication. Binding of the Origin Recognition Complex (ORC) to DNA initiates the ATP-dependent recruitment of Cdc6, Cdt1 and Mcm2-7 loading, but the structural details for timely ATPase site regulation and for how loading can be impeded by inhibitory signals, such as cyclin-dependent kinase phosphorylation, are unknown. Using cryo-electron microscopy, we have determined several structures of S. cerevisiae ORC·DNA·Cdc6 intermediates at 2.5-2.7 Å resolution. These structures reveal distinct ring conformations of the initiator·co-loader assembly and inactive ATPase site configurations for ORC and Cdc6. The Orc6 N-terminal domain laterally engages the ORC·Cdc6 ring in a manner that is incompatible with productive Mcm2-7 docking, while deletion of this Orc6 region alleviates the CDK-mediated inhibition of Mcm7 recruitment. Our findings support a model in which Orc6 promotes the assembly of an autoinhibited ORC·DNA·Cdc6 intermediate to block origin licensing in response to CDK phosphorylation and to avert DNA re-replication.
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Affiliation(s)
- Jan Marten Schmidt
- Friedrich Miescher Institute for Biomedical Research, Basel, 4058, Switzerland
- University of Basel, Basel, 4051, Switzerland
- Novartis Institutes for Biomedical Research, Basel, 4033, Switzerland
| | - Ran Yang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Ashish Kumar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Olivia Hunker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Jan Seebacher
- Friedrich Miescher Institute for Biomedical Research, Basel, 4058, Switzerland
| | - Franziska Bleichert
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA.
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9
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Zhao H, Gezi G, Tian X, Jia P, Morigen M, Fan L. Lysophosphatidic Acid-Induced EGFR Transactivation Promotes Gastric Cancer Cell DNA Replication by Stabilizing Geminin in the S Phase. Front Pharmacol 2021; 12:706240. [PMID: 34658851 PMCID: PMC8511314 DOI: 10.3389/fphar.2021.706240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 08/13/2021] [Indexed: 11/15/2022] Open
Abstract
Geminin, an inhibitor of the DNA replication licensing factor, chromatin licensing and DNA replication factor (Cdt) 1, is essential for the maintenance of genomic integrity. As a multifunctional protein, geminin is also involved in tumor progression, but the molecular details are largely unknown. Here, we found that lysophosphatidic acid (LPA)–induced upregulation of geminin was specific to gastric cancer cells. LPA acted via LPA receptor (LPAR) 3 and matrix metalloproteinases (MMPs) signaling to transactivate epidermal growth factor receptor (EGFR) (Y1173) and thereby stabilize geminin expression level during the S phase. LPA also induced the expression of deubiquitinating protein (DUB) 3, which prevented geminin degradation. These results reveal a novel mechanism underlying gastric cancer progression that involves the regulation of geminin stability by LPA-induced EGFR transactivation and provide potential targets for the signaling pathway and tumor cell–specific inhibitors.
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Affiliation(s)
- Haile Zhao
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Gezi Gezi
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Xiaoxia Tian
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Peijun Jia
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Morigen Morigen
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Lifei Fan
- State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot, China
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10
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Santos-Rosa H, Millán-Zambrano G, Han N, Leonardi T, Klimontova M, Nasiscionyte S, Pandolfini L, Tzelepis K, Bartke T, Kouzarides T. Methylation of histone H3 at lysine 37 by Set1 and Set2 prevents spurious DNA replication. Mol Cell 2021; 81:2793-2807.e8. [PMID: 33979575 PMCID: PMC7612968 DOI: 10.1016/j.molcel.2021.04.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 02/09/2021] [Accepted: 04/21/2021] [Indexed: 11/22/2022]
Abstract
DNA replication initiates at genomic locations known as origins of replication, which, in S. cerevisiae, share a common DNA consensus motif. Despite being virtually nucleosome-free, origins of replication are greatly influenced by the surrounding chromatin state. Here, we show that histone H3 lysine 37 mono-methylation (H3K37me1) is catalyzed by Set1p and Set2p and that it regulates replication origin licensing. H3K37me1 is uniformly distributed throughout most of the genome, but it is scarce at replication origins, where it increases according to the timing of their firing. We find that H3K37me1 hinders Mcm2 interaction with chromatin, maintaining low levels of MCM outside of conventional replication origins. Lack of H3K37me1 results in defective DNA replication from canonical origins while promoting replication events at inefficient and non-canonical sites. Collectively, our results indicate that H3K37me1 ensures correct execution of the DNA replication program by protecting the genome from inappropriate origin licensing and spurious DNA replication.
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Affiliation(s)
- Helena Santos-Rosa
- The Gurdon Institute and Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.
| | - Gonzalo Millán-Zambrano
- The Gurdon Institute and Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK; Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), 41092 Sevilla, Spain
| | - Namshik Han
- The Gurdon Institute and Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK; Milner Therapeutics Institute, University of Cambridge, Cambridge CB2 0AW, UK
| | - Tommaso Leonardi
- The Gurdon Institute and Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK; Center for Genomic Science Istituto Italiano di Tecnologia (IIT), 20139 Milano, Italy
| | - Marie Klimontova
- The Gurdon Institute and Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Simona Nasiscionyte
- Institute of Functional Epigenetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Luca Pandolfini
- The Gurdon Institute and Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK; Istituto Italiano di Tecnologia (IIT), Center for Human Technologies (CHT), 16152 Genova, Italy
| | - Kostantinos Tzelepis
- The Gurdon Institute and Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK; Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge CB10 1SA, UK
| | - Till Bartke
- Institute of Functional Epigenetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Tony Kouzarides
- The Gurdon Institute and Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.
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11
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Amin A, Wu R, Cheung MH, Scott JF, Wang Z, Zhou Z, Liu C, Zhu G, Wong CKC, Yu Z, Liang C. An Essential and Cell-Cycle-Dependent ORC Dimerization Cycle Regulates Eukaryotic Chromosomal DNA Replication. Cell Rep 2021; 30:3323-3338.e6. [PMID: 32160540 DOI: 10.1016/j.celrep.2020.02.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 10/04/2019] [Accepted: 02/10/2020] [Indexed: 12/24/2022] Open
Abstract
Eukaryotic DNA replication licensing is a prerequisite for, and plays a role in, regulating genome duplication that occurs exactly once per cell cycle. ORC (origin recognition complex) binds to and marks replication origins throughout the cell cycle and loads other replication-initiation proteins onto replication origins to form pre-replicative complexes (pre-RCs), completing replication licensing. However, how an asymmetric single-heterohexameric ORC structure loads the symmetric MCM (minichromosome maintenance) double hexamers is controversial, and importantly, it remains unknown when and how ORC proteins associate with the newly replicated origins to protect them from invasion by histones. Here, we report an essential and cell-cycle-dependent ORC "dimerization cycle" that plays three fundamental roles in the regulation of DNA replication: providing a symmetric platform to load the symmetric pre-RCs, marking and protecting the nascent sister replication origins for the next licensing, and playing a crucial role to prevent origin re-licensing within the same cell cycle.
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Affiliation(s)
- Aftab Amin
- School of Chinese Medicine and Department of Biology, Hong Kong Baptist University, Hong Kong, China; Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Rentian Wu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Man Hei Cheung
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - John F Scott
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Ziyi Wang
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Zijing Zhou
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Changdong Liu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Guang Zhu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Chris Kong-Chu Wong
- School of Chinese Medicine and Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Zhiling Yu
- School of Chinese Medicine and Department of Biology, Hong Kong Baptist University, Hong Kong, China.
| | - Chun Liang
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China; The First Clinical Medicine College, Guangzhou University of Chinese Medicine, Guangzhou, China; EnKang Pharmaceuticals Limited, Guangzhou, China.
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12
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He Z, Houghton PJ, Williams TM, Shen C. Regulation of DNA duplication by the mTOR signaling pathway. Cell Cycle 2021; 20:742-751. [PMID: 33691584 DOI: 10.1080/15384101.2021.1897271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Accurate and complete DNA replication and separation are essential for genetic information inheritance and organism maintenance. Errors in DNA duplication are the main source of genetic instability. Understanding DNA duplication regulation is the key to elucidate the mechanisms and find treatment strategies for human genetic disorders, especially cancer. The mechanistic target of rapamycin (mTOR) is a central regulator of cell growth and proliferation by integrating and processing extracellular and intracellular signals to monitor the well-being of cell physiology. mTOR signaling dysregulation is associated with many human diseases including cancer and diabetes. Emerging evidence has demonstrated that mTOR signaling plays a key role in DNA duplication. We herein review the current knowledge of mTOR signaling in the regulation of DNA replication origin licensing, replication fork progression, and stabilization.
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Affiliation(s)
- Zhengfu He
- Department of Thoracic Surgery, Sir Run Run Shaw Hospital, College of Medicine Zhejiang University, Hangzhou, China
| | - Peter J Houghton
- The Greehey Children's Cancer Research Institute, the University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Terence M Williams
- Department of Radiation Oncology, Beckman Research Institute, City of Hope National Medical Center, Duarte, California, USA
| | - Changxian Shen
- Department of Radiation Oncology, Beckman Research Institute, City of Hope National Medical Center, Duarte, California, USA
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13
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Fouad S, Hauton D, D'Angiolella V. E2F1: Cause and Consequence of DNA Replication Stress. Front Mol Biosci 2021; 7:599332. [PMID: 33665206 PMCID: PMC7921158 DOI: 10.3389/fmolb.2020.599332] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 11/30/2020] [Indexed: 12/12/2022] Open
Abstract
In mammalian cells, cell cycle entry occurs in response to the correct stimuli and is promoted by the transcriptional activity of E2F family members. E2F proteins regulate the transcription of S phase cyclins and genes required for DNA replication, DNA repair, and apoptosis. The activity of E2F1, the archetypal and most heavily studied E2F family member, is tightly controlled by the DNA damage checkpoints to modulate cell cycle progression and initiate programmed cell death, when required. Altered tumor suppressor and oncogenic signaling pathways often result in direct or indirect interference with E2F1 regulation to ensure higher rates of cell proliferation independently of external cues. Despite a clear link between dysregulated E2F1 activity and cancer progression, literature on the contribution of E2F1 to DNA replication stress phenotypes is somewhat scarce. This review discusses how dysfunctional tumor suppressor and oncogenic signaling pathways promote the disruption of E2F1 transcription and hence of its transcriptional targets, and how such events have the potential to drive DNA replication stress. In addition to the involvement of E2F1 upstream of DNA replication stress, this manuscript also considers the role of E2F1 as a downstream effector of the response to this type of cellular stress. Lastly, the review introduces some reflections on how E2F1 activity is integrated with checkpoint control through post-translational regulation, and proposes an exploitable tumor weakness based on this axis.
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Affiliation(s)
- Shahd Fouad
- Department of Oncology, Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - David Hauton
- Department of Oncology, Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Vincenzo D'Angiolella
- Department of Oncology, Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
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14
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Novák B, Tyson JJ. Computational modeling of chromosome re-replication in mutant strains of fission yeast. Mol Biol Cell 2021; 32:830-841. [PMID: 33534609 PMCID: PMC8108527 DOI: 10.1091/mbc.e20-09-0610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Typically cells replicate their genome only once per division cycle, but under some circumstances, both natural and unnatural, cells synthesize an overabundance of DNA, either in a disorganized manner (“overreplication”) or by a systematic doubling of chromosome number (“endoreplication”). These variations on the theme of DNA replication and division have been studied in strains of fission yeast, Schizosaccharomyces pombe, carrying mutations that interfere with the function of mitotic cyclin-dependent kinase (Cdk1:Cdc13) without impeding the roles of DNA-replication loading factor (Cdc18) and S-phase cyclin-dependent kinase (Cdk1:Cig2). Some of these mutations support endoreplication, and some overreplication. In this paper, we propose a dynamical model of the interactions among the proteins governing DNA replication and cell division in fission yeast. By computational simulations of the mathematical model, we account for the observed phenotypes of these re-replicating mutants, and by theoretical analysis of the dynamical system, we provide insight into the molecular distinctions between overreplicating and endoreplicating cells. In the case of induced overproduction of regulatory proteins, our model predicts that cells first switch from normal mitotic cell cycles to growth-controlled endoreplication, and ultimately to disorganized overreplication, parallel to the slow increase of protein to very high levels.
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Affiliation(s)
- Béla Novák
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - John J Tyson
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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15
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Abstract
The Origin Recognition Complex (ORC) is an evolutionarily conserved six-subunit protein complex that binds specific sites at many locations to coordinately replicate the entire eukaryote genome. Though highly conserved in structure, ORC’s selectivity for replication origins has diverged tremendously between yeasts and humans to adapt to vastly different life cycles. In this work, we demonstrate that the selectivity determinant of ORC for DNA binding lies in a 19-amino acid insertion helix in the Orc4 subunit, which is present in yeast but absent in human. Removal of this motif from Orc4 transforms the yeast ORC, which selects origins based on base-specific binding at defined locations, into one whose selectivity is dictated by chromatin landscape and afforded with plasticity, as reported for human. Notably, the altered yeast ORC has acquired an affinity for regions near transcriptional start sites (TSSs), which the human ORC also favors. In most model yeast species the Origin Recognition Complex (ORC) binds defined and species-specific base sequences while in humans what determines the binding appears to be more complex. Here the authors reveal that the yeast’s ORC complex binding specificity is dependent on a 19-amino acid insertion helix in the Orc4 subunit which is lost in human.
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16
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Under-Replicated DNA: The Byproduct of Large Genomes? Cancers (Basel) 2020; 12:cancers12102764. [PMID: 32992928 PMCID: PMC7601121 DOI: 10.3390/cancers12102764] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 12/28/2022] Open
Abstract
In this review, we provide an overview of how proliferating eukaryotic cells overcome one of the main threats to genome stability: incomplete genomic DNA replication during S phase. We discuss why it is currently accepted that double fork stalling (DFS) events are unavoidable events in higher eukaryotes with large genomes and which responses have evolved to cope with its main consequence: the presence of under-replicated DNA (UR-DNA) outside S phase. Particular emphasis is placed on the processes that constrain the detrimental effects of UR-DNA. We discuss how mitotic DNA synthesis (MiDAS), mitotic end joining events and 53BP1 nuclear bodies (53BP1-NBs) deal with such specific S phase DNA replication remnants during the subsequent phases of the cell cycle.
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17
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Li C, Ge M, Chen D, Sun T, Jiang H, Xie Y, Lu H, Zhang B, Han L, Chen J, Zhu J. RPL21 siRNA Blocks Proliferation in Pancreatic Cancer Cells by Inhibiting DNA Replication and Inducing G1 Arrest and Apoptosis. Front Oncol 2020; 10:1730. [PMID: 33014855 PMCID: PMC7509406 DOI: 10.3389/fonc.2020.01730] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 08/03/2020] [Indexed: 12/12/2022] Open
Abstract
Background Our previous study showed that the ribosomal protein L21 (RPL21) may play an important role in the development and survival of pancreatic cancer. In this article, RNA interference (RNAi) experiments were performed with RPL21-specific small interfering RNA (siRNA) to elucidate the mechanism by which RPL21 controls PC PANC-1 and BxPC-3 cell proliferation. Methods In the present study, PANC-1, BxPC-3 cells, and BALB/c nude mice were used to investigate antitumor effect and mechanism by which RPL21 controls cell proliferation and apoptosis in vitro and in vivo. The effects of RPL21 knockdown on PANC-1 and BxPC-3 cell proliferation, cell cycle and cell apoptosis in vitro were determined using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assays and flow cytometry assay. The mechanism of RPL21 regulating cell proliferation was investigated using transcriptome sequencing analysis and luciferase reporter assay. The effects of RPL21 knockdown on PANC-1 and BxPC-3 cell proliferation in vivo were determined using BALB/c nude mice tumor model. Results In PANC-1 and BxPC-3 cells, the knockdown of RPL21 expression with corresponding siRNA suppressed cell proliferation in vitro and in vivo, inhibited DNA replication, and induced arrests in the G1 phase of the cell cycle. Further results showed that the mini-chromosome maintenance (MCM) protein family (MCM2-7), CCND1 and CCNE1 were down-regulated significantly in PANC-1 and BxPC-3 cells after transfected with RPL21 siRNA, which suggests that the suppression of DNA replication is due to the reduced expression of MCM2-7 family, and the induction of G1 arrest is correlated with the inhibition of CCND1 and CCNE1. Luciferase reporter assay showed that RPL21 controls the DNA replication and G1-S phase progression possibly through the regulation of E2F1 transcription factor in PC cells. Moreover, RPL21 siRNA showed an apoptosis-inducing effect only in BxPC-3 and PANC-1 cells but not in normal HPDE6-C7 cells. The increase of caspase-8 activities and the loss of mitochondrial membrane potential after RPL21 silencing indicates that the RPL21 gene may be involved in caspase-8-related mitochondrial apoptosis. Conclusion Our findings suggest that siRNA against the RPL21 gene possesses a potential anti-cancer activity for PC cells by inhibiting their proliferation and DNA replication, as well as inducing cell cycle G1 arrest and cell apoptosis.
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Affiliation(s)
- Chaodong Li
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China.,Jecho Biopharmaceuticals Co., Ltd., Tianjin, China
| | - Mei Ge
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Laiyi Center for Biopharmaceutical R&D, Shanghai, China
| | - Daijie Chen
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China.,China State Institute of Pharmaceutical Industry, Shanghai, China
| | - Tao Sun
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Hua Jiang
- Jecho Laboratories, Inc., Frederick, MD, United States
| | - Yueqing Xie
- Jecho Laboratories, Inc., Frederick, MD, United States
| | - Huili Lu
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Baohong Zhang
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Lei Han
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China.,Jecho Biopharmaceuticals Co., Ltd., Tianjin, China
| | - Junsheng Chen
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Jianwei Zhu
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China.,Jecho Biopharmaceuticals Co., Ltd., Tianjin, China.,Jecho Laboratories, Inc., Frederick, MD, United States
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18
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McDaniel SL, Hollatz AJ, Branstad AM, Gaskill MM, Fox CA, Harrison MM. Tissue-Specific DNA Replication Defects in Drosophila melanogaster Caused by a Meier-Gorlin Syndrome Mutation in Orc4. Genetics 2020; 214:355-367. [PMID: 31818869 PMCID: PMC7017028 DOI: 10.1534/genetics.119.302938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 12/05/2019] [Indexed: 02/07/2023] Open
Abstract
Meier-Gorlin syndrome is a rare recessive disorder characterized by a number of distinct tissue-specific developmental defects. Genes encoding members of the origin recognition complex (ORC) and additional proteins essential for DNA replication (CDC6, CDT1, GMNN, CDC45, MCM5, and DONSON) are mutated in individuals diagnosed with MGS. The essential role of ORC is to license origins during the G1 phase of the cell cycle, but ORC has also been implicated in several nonreplicative functions. Because of its essential role in DNA replication, ORC is required for every cell division during development. Thus, it is unclear how the Meier-Gorlin syndrome mutations in genes encoding ORC lead to the tissue-specific defects associated with the disease. To begin to address these issues, we used Cas9-mediated genome engineering to generate a Drosophila melanogaster model of individuals carrying a specific Meier-Gorlin syndrome mutation in ORC4 along with control strains. Together these strains provide the first metazoan model for an MGS mutation in which the mutation was engineered at the endogenous locus along with precisely defined control strains. Flies homozygous for the engineered MGS allele reach adulthood, but with several tissue-specific defects. Genetic analysis revealed that this Orc4 allele was a hypomorph. Mutant females were sterile, and phenotypic analyses suggested that defects in DNA replication was an underlying cause. By leveraging the well-studied Drosophila system, we provide evidence that a disease-causing mutation in Orc4 disrupts DNA replication, and we propose that in individuals with MGS defects arise preferentially in tissues with a high-replication demand.
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Affiliation(s)
- Stephen L McDaniel
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Allison J Hollatz
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Anna M Branstad
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Marissa M Gaskill
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Catherine A Fox
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
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19
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Wu X, Li S, Hu X, Xiang X, Halloran M, Yang L, Williams TM, Houghton PJ, Shen C, He Z. mTOR Signaling Upregulates CDC6 via Suppressing miR-3178 and Promotes the Loading of DNA Replication Helicase. Sci Rep 2019; 9:9805. [PMID: 31285446 PMCID: PMC6614418 DOI: 10.1038/s41598-019-46052-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 06/21/2019] [Indexed: 12/12/2022] Open
Abstract
mTOR signaling pathway is deregulated in most cancers and uncontrolled cell cycle progression is a hallmark of cancer cell. However, the precise molecular mechanisms of the regulation of DNA replication and chromatin metabolism by mTOR signaling are largely unknown. We herein report that mTOR signaling promotes the loading of MCM2-7 helicase onto chromatin and upregulates DNA replication licensing factor CDC6. Pharmacological inhibition of mTOR kinase resulted in CHK1 checkpoint activation and decreased MCM2-7 replication helicase and PCNA associated with chromatins. Further pharmacological and genetic studies demonstrated CDC6 is positively controlled by mTORC1-S6K1 and mTORC2 signaling. miRNA screening revealed mTOR signaling suppresses miR-3178 thereby upregulating CDC6. Analysis of TCGA data found that CDC6 is overexpressed in most cancers and associates with the poor survival of cancer patients. Our findings suggest that mTOR signaling may control DNA replication origin licensing and replisome stability thereby cell cycle progression through CDC6 regulation.
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Affiliation(s)
- Xianjin Wu
- Key Laboratory of Hunan Province for Study and Utilization of Ethnic Medicinal Plant Resources, College of Biological and Food Engineering, Huaihua University, Huaihua, 418008, China
| | - Shenghua Li
- Key Laboratory of Hunan Province for Study and Utilization of Ethnic Medicinal Plant Resources, College of Biological and Food Engineering, Huaihua University, Huaihua, 418008, China
| | - Xing Hu
- Key Laboratory of Hunan Province for Study and Utilization of Ethnic Medicinal Plant Resources, College of Biological and Food Engineering, Huaihua University, Huaihua, 418008, China
| | - Xiaoliang Xiang
- Key Laboratory of Hunan Province for Study and Utilization of Ethnic Medicinal Plant Resources, College of Biological and Food Engineering, Huaihua University, Huaihua, 418008, China
| | - Megan Halloran
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Linlin Yang
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Terence M Williams
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, 43210, USA
| | - Peter J Houghton
- The Greehey Children's Cancer Research Institute, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, 78229, USA
| | - Changxian Shen
- Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, 43210, USA.
| | - Zhengfu He
- Department of Thoracic Surgery, Sir Run Run Shaw Hospital, College of Medicine Zhejiang University, Hangzhou, 310016, China.
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20
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Wu R, Amin A, Wang Z, Huang Y, Man-Hei Cheung M, Yu Z, Yang W, Liang C. The interaction networks of the budding yeast and human DNA replication-initiation proteins. Cell Cycle 2019; 18:723-741. [PMID: 30890025 DOI: 10.1080/15384101.2019.1586509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
DNA replication is a stringently regulated cellular process. In proliferating cells, DNA replication-initiation proteins (RIPs) are sequentially loaded onto replication origins during the M-to-G1 transition to form the pre-replicative complex (pre-RC), a process known as replication licensing. Subsequently, additional RIPs are recruited to form the pre-initiation complex (pre-IC). RIPs and their regulators ensure that chromosomal DNA is replicated exactly once per cell cycle. Origin recognition complex (ORC) binds to, and marks replication origins throughout the cell cycle and recruits other RIPs including Noc3p, Ipi1-3p, Cdt1p, Cdc6p and Mcm2-7p to form the pre-RC. The detailed mechanisms and regulation of the pre-RC and its exact architecture still remain unclear. In this study, pairwise protein-protein interactions among 23 budding yeast and 16 human RIPs were systematically and comprehensively examined by yeast two-hybrid analysis. This study tested 470 pairs of yeast and 196 pairs of human RIPs, from which 113 and 96 positive interactions, respectively, were identified. While many of these interactions were previously reported, some were novel, including various ORC and MCM subunit interactions, ORC self-interactions, and the interactions of IPI3 and NOC3 with several pre-RC and pre-IC proteins. Ten of the novel interactions were further confirmed by co-immunoprecipitation assays. Furthermore, we identified the conserved interaction networks between the yeast and human RIPs. This study provides a foundation and framework for further understanding the architectures, interactions and functions of the yeast and human pre-RC and pre-IC.
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Affiliation(s)
- Rentian Wu
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China.,b Guangzhou HKUST Fok Ying Tung Research Institute , Guangzhou , China
| | - Aftab Amin
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China.,b Guangzhou HKUST Fok Ying Tung Research Institute , Guangzhou , China.,c School of Chinese Medicine , Hong Kong Baptist University , Guangzhou , China
| | - Ziyi Wang
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China
| | - Yining Huang
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China
| | - Marco Man-Hei Cheung
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China.,b Guangzhou HKUST Fok Ying Tung Research Institute , Guangzhou , China
| | - Zhiling Yu
- c School of Chinese Medicine , Hong Kong Baptist University , Guangzhou , China
| | - Wei Yang
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China.,d Guangdong Lewwin Pharmaceutical Research Institute Co., Ltd , Hong Kong , China
| | - Chun Liang
- a Division of Life Science, Center for Cancer Research and State Key Lab for Molecular Neuroscience , Hong Kong University of Science and Technology , Hong Kong , China.,b Guangzhou HKUST Fok Ying Tung Research Institute , Guangzhou , China.,e ntelgen Limited , Hong Kong-Guangzhou-Foshan , China
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21
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Control of Eukaryotic DNA Replication Initiation-Mechanisms to Ensure Smooth Transitions. Genes (Basel) 2019; 10:genes10020099. [PMID: 30700044 PMCID: PMC6409694 DOI: 10.3390/genes10020099] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 01/25/2019] [Accepted: 01/25/2019] [Indexed: 02/06/2023] Open
Abstract
DNA replication differs from most other processes in biology in that any error will irreversibly change the nature of the cellular progeny. DNA replication initiation, therefore, is exquisitely controlled. Deregulation of this control can result in over-replication characterized by repeated initiation events at the same replication origin. Over-replication induces DNA damage and causes genomic instability. The principal mechanism counteracting over-replication in eukaryotes is a division of replication initiation into two steps—licensing and firing—which are temporally separated and occur at distinct cell cycle phases. Here, we review this temporal replication control with a specific focus on mechanisms ensuring the faultless transition between licensing and firing phases.
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22
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Chappidi N, De Gregorio G, Ferrari S. Replication stress-induced Exo1 phosphorylation is mediated by Rad53/Pph3 and Exo1 nuclear localization is controlled by 14-3-3 proteins. Cell Div 2019; 14:1. [PMID: 30622624 PMCID: PMC6318887 DOI: 10.1186/s13008-018-0044-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 12/24/2018] [Indexed: 12/22/2022] Open
Abstract
Background Mechanisms controlling DNA resection at sites of damage and affecting genome stability have been the subject of deep investigation, though their complexity is not yet fully understood. Specifically, the regulatory role of post-translational modifications in the localization, stability and function of DNA repair proteins is an important aspect of such complexity. Results Here, we took advantage of the superior resolution of phosphorylated proteins provided by Phos-Tag technology to study pathways controlling the reversible phosphorylation of yeast Exo1, an exonuclease involved in a number of DNA repair pathways. We report that Rad53, a checkpoint kinase downstream of Mec1, is responsible for Exo1 phosphorylation in response to DNA replication stress and we demonstrate a role for the type-2A protein phosphatase Pph3 in the dephosphorylation of both Rad53 and Exo1 during checkpoint recovery. Fluorescence microscopy studies showed that Rad53-dependent phosphorylation is not required for the recruitment or the release of Exo1 from the nucleus, whereas 14-3-3 proteins are necessary for Exo1 nuclear translocation. Conclusions By shedding light on the mechanism of Exo1 control, these data underscore the importance of post-translational modifications and protein interactions in the regulation of DNA end resection.
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Affiliation(s)
- Nagaraja Chappidi
- Institute of Molecular Cancer Research, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Giuseppe De Gregorio
- Institute of Molecular Cancer Research, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Stefano Ferrari
- Institute of Molecular Cancer Research, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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23
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Dewachter L, Verstraeten N, Fauvart M, Michiels J. An integrative view of cell cycle control in Escherichia coli. FEMS Microbiol Rev 2018; 42:116-136. [PMID: 29365084 DOI: 10.1093/femsre/fuy005] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 01/19/2018] [Indexed: 11/14/2022] Open
Abstract
Bacterial proliferation depends on the cells' capability to proceed through consecutive rounds of the cell cycle. The cell cycle consists of a series of events during which cells grow, copy their genome, partition the duplicated DNA into different cell halves and, ultimately, divide to produce two newly formed daughter cells. Cell cycle control is of the utmost importance to maintain the correct order of events and safeguard the integrity of the cell and its genomic information. This review covers insights into the regulation of individual key cell cycle events in Escherichia coli. The control of initiation of DNA replication, chromosome segregation and cell division is discussed. Furthermore, we highlight connections between these processes. Although detailed mechanistic insight into these connections is largely still emerging, it is clear that the different processes of the bacterial cell cycle are coordinated to one another. This careful coordination of events ensures that every daughter cell ends up with one complete and intact copy of the genome, which is vital for bacterial survival.
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Affiliation(s)
- Liselot Dewachter
- Centre of Microbial and Plant Genetics, KU Leuven-University of Leuven, B-3001 Leuven, Belgium.,VIB Center for Microbiology, B-3001 Leuven, Belgium
| | - Natalie Verstraeten
- Centre of Microbial and Plant Genetics, KU Leuven-University of Leuven, B-3001 Leuven, Belgium.,VIB Center for Microbiology, B-3001 Leuven, Belgium
| | - Maarten Fauvart
- Centre of Microbial and Plant Genetics, KU Leuven-University of Leuven, B-3001 Leuven, Belgium.,VIB Center for Microbiology, B-3001 Leuven, Belgium.,Department of Life Sciences and Imaging, Smart Electronics Unit, imec, B-3001 Leuven, Belgium
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven-University of Leuven, B-3001 Leuven, Belgium.,VIB Center for Microbiology, B-3001 Leuven, Belgium
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24
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Liao H, Ji F, Helleday T, Ying S. Mechanisms for stalled replication fork stabilization: new targets for synthetic lethality strategies in cancer treatments. EMBO Rep 2018; 19:embr.201846263. [PMID: 30108055 DOI: 10.15252/embr.201846263] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 07/06/2018] [Accepted: 07/20/2018] [Indexed: 01/24/2023] Open
Abstract
Timely and faithful duplication of the entire genome depends on completion of replication. Replication forks frequently encounter obstacles that may cause genotoxic fork stalling. Nevertheless, failure to complete replication rarely occurs under normal conditions, which is attributed to an intricate network of proteins that serves to stabilize, repair and restart stalled forks. Indeed, many of the components in this network are encoded by tumour suppressor genes, and their loss of function by mutation or deletion generates genomic instability, a hallmark of cancer. Paradoxically, the same fork-protective network also confers resistance of cancer cells to chemotherapeutic drugs that induce high-level replication stress. Here, we review the mechanisms and major pathways rescuing stalled replication forks, with a focus on fork stabilization preventing fork collapse. A coherent understanding of how cells protect their replication forks will not only provide insight into how cells maintain genome stability, but also unravel potential therapeutic targets for cancers refractory to conventional chemotherapies.
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Affiliation(s)
- Hongwei Liao
- Department of Pharmacology & Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital, Institute of Respiratory Diseases, Zhejiang University School of Medicine, Hangzhou, China
| | - Fang Ji
- Department of Pharmacology & Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital, Institute of Respiratory Diseases, Zhejiang University School of Medicine, Hangzhou, China
| | - Thomas Helleday
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden .,Sheffield Cancer Centre, Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
| | - Songmin Ying
- Department of Pharmacology & Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital, Institute of Respiratory Diseases, Zhejiang University School of Medicine, Hangzhou, China
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25
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Szambowska A, Tessmer I, Prus P, Schlott B, Pospiech H, Grosse F. Cdc45-induced loading of human RPA onto single-stranded DNA. Nucleic Acids Res 2017; 45:3217-3230. [PMID: 28100698 PMCID: PMC5389570 DOI: 10.1093/nar/gkw1364] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 01/02/2017] [Indexed: 11/14/2022] Open
Abstract
Cell division cycle protein 45 (Cdc45) is an essential component of the eukaryotic replicative DNA helicase. We found that human Cdc45 forms a complex with the single-stranded DNA (ssDNA) binding protein RPA. Moreover, it actively loads RPA onto nascent ssDNA. Pull-down assays and surface plasmon resonance studies revealed that Cdc45-bound RPA complexed with ssDNA in the 8–10 nucleotide binding mode, but dissociated when RPA covered a 30-mer. Real-time analysis of RPA-ssDNA binding demonstrated that Cdc45 catalytically loaded RPA onto ssDNA. This placement reaction required physical contacts of Cdc45 with the RPA70A subdomain. Our results imply that Cdc45 controlled stabilization of the 8-nt RPA binding mode, the subsequent RPA transition into 30-mer mode and facilitated an ordered binding to ssDNA. We propose that a Cdc45-mediated loading guarantees a seamless deposition of RPA on newly emerging ssDNA at the nascent replication fork.
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Affiliation(s)
- Anna Szambowska
- Research Group Biochemistry, Leibniz Institute on Aging-Fritz Lipmann Institute, Beutenbergstrasse 11, D-07745 Jena, Germany
| | - Ingrid Tessmer
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Josef Schneider Strasse 2, D-97080 Würzburg, Germany
| | - Piotr Prus
- Biocenter Oulu, P.O. Box 5000, 90014 University of Oulu, Finland
| | - Bernhard Schlott
- Research Group Biochemistry, Leibniz Institute on Aging-Fritz Lipmann Institute, Beutenbergstrasse 11, D-07745 Jena, Germany.,Proteomics Core Facility, Leibniz Institute on Aging-Fritz Lipmann Institute, Beutenbergstrasse 11, D-07745 Jena, Germany
| | - Helmut Pospiech
- Research Group Biochemistry, Leibniz Institute on Aging-Fritz Lipmann Institute, Beutenbergstrasse 11, D-07745 Jena, Germany.,Faculty of Biochemistry and Molecular Medicine, P.O. Box 5000, 90014 University of Oulu, Finland
| | - Frank Grosse
- Research Group Biochemistry, Leibniz Institute on Aging-Fritz Lipmann Institute, Beutenbergstrasse 11, D-07745 Jena, Germany.,Center for Molecular Biomedicine, Friedrich-Schiller University, Biochemistry Department, Jena, Germany
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The Intra-S Checkpoint Responses to DNA Damage. Genes (Basel) 2017; 8:genes8020074. [PMID: 28218681 PMCID: PMC5333063 DOI: 10.3390/genes8020074] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Revised: 02/08/2017] [Accepted: 02/08/2017] [Indexed: 02/03/2023] Open
Abstract
Faithful duplication of the genome is a challenge because DNA is susceptible to damage by a number of intrinsic and extrinsic genotoxins, such as free radicals and UV light. Cells activate the intra-S checkpoint in response to damage during S phase to protect genomic integrity and ensure replication fidelity. The checkpoint prevents genomic instability mainly by regulating origin firing, fork progression, and transcription of G1/S genes in response to DNA damage. Several studies hint that regulation of forks is perhaps the most critical function of the intra-S checkpoint. However, the exact role of the checkpoint at replication forks has remained elusive and controversial. Is the checkpoint required for fork stability, or fork restart, or to prevent fork reversal or fork collapse, or activate repair at replication forks? What are the factors that the checkpoint targets at stalled replication forks? In this review, we will discuss the various pathways activated by the intra-S checkpoint in response to damage to prevent genomic instability.
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A defective dNTP pool hinders DNA replication in cell cycle-reactivated terminally differentiated muscle cells. Cell Death Differ 2017; 24:774-784. [PMID: 28186504 DOI: 10.1038/cdd.2017.4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 01/02/2017] [Accepted: 01/10/2017] [Indexed: 02/06/2023] Open
Abstract
Terminally differentiated cells are defined by their inability to proliferate. When forced to re-enter the cell cycle, they generally cannot undergo long-term replication. Our previous work with myotubes has shown that these cells fail to proliferate because of their intrinsic inability to complete DNA replication. Moreover, we have reported pronounced modifications of deoxynucleotide metabolism during myogenesis. Here we investigate the causes of incomplete DNA duplication in cell cycle-reactivated myotubes (rMt). We find that rMt possess extremely low levels of thymidine triphosphate (dTTP), resulting in very slow replication fork rates. Exogenous administration of thymidine or forced expression of thymidine kinase increases deoxynucleotide availability, allowing extended and faster DNA replication. Inadequate dTTP levels are caused by selective, differentiation-dependent, cell cycle-resistant suppression of genes encoding critical synthetic enzymes, chief among which is thymidine kinase 1. We conclude that lack of dTTP is at least partially responsible for the inability of myotubes to proliferate and speculate that it constitutes an emergency barrier against unwarranted DNA replication in terminally differentiated cells.
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29
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Abstract
As the ratio of the copy number of the most replicated to the unreplicated regions in the same chromosome, the definition of chromosomal replication complexity (CRC) appears to leave little room for variation, being either two during S-phase or one otherwise. However, bacteria dividing faster than they replicate their chromosome spike CRC to four and even eight. A recent experimental inquiry about the limits of CRC in Escherichia coli revealed two major reasons to avoid elevating it further: (i) increased chromosomal fragmentation and (ii) complications with subsequent double-strand break repair. Remarkably, examples of stable elevated CRC in eukaryotic chromosomes are well known under various terms like "differential replication," "underreplication," "DNA puffs," "onion-skin replication," or "re-replication" and highlight the phenomenon of static replication fork (sRF). To accurately describe the resulting "amplification by overinitiation," I propose a new term: "replification" (subchromosomal overreplication). In both prokaryotes and eukaryotes, replification, via sRF processing, causes double-strand DNA breaks and, with their repair elevating chromosomal rearrangements, represents a novel genome instability factor. I suggest how static replication bubbles could be stabilized and speculate that some tandem duplications represent such persistent static bubbles. Moreover, I propose how static replication bubbles could be transformed into tandem duplications, double minutes, or inverted triplications. Possible experimental tests of these models are discussed.
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Affiliation(s)
- Andrei Kuzminov
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail:
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30
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Reusswig KU, Zimmermann F, Galanti L, Pfander B. Robust Replication Control Is Generated by Temporal Gaps between Licensing and Firing Phases and Depends on Degradation of Firing Factor Sld2. Cell Rep 2016; 17:556-569. [DOI: 10.1016/j.celrep.2016.09.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 08/10/2016] [Accepted: 09/02/2016] [Indexed: 10/20/2022] Open
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31
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Inevitability and containment of replication errors for eukaryotic genome lengths spanning megabase to gigabase. Proc Natl Acad Sci U S A 2016; 113:E5765-74. [PMID: 27630194 PMCID: PMC5047159 DOI: 10.1073/pnas.1603241113] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The replication of DNA is initiated at particular sites on the genome called replication origins (ROs). Understanding the constraints that regulate the distribution of ROs across different organisms is fundamental for quantifying the degree of replication errors and their downstream consequences. Using a simple probabilistic model, we generate a set of predictions on the extreme sensitivity of error rates to the distribution of ROs, and how this distribution must therefore be tuned for genomes of vastly different sizes. As genome size changes from megabases to gigabases, we predict that regularity of RO spacing is lost, that large gaps between ROs dominate error rates but are heavily constrained by the mean stalling distance of replication forks, and that, for genomes spanning ∼100 megabases to ∼10 gigabases, errors become increasingly inevitable but their number remains very small (three or less). Our theory predicts that the number of errors becomes significantly higher for genome sizes greater than ∼10 gigabases. We test these predictions against datasets in yeast, Arabidopsis, Drosophila, and human, and also through direct experimentation on two different human cell lines. Agreement of theoretical predictions with experiment and datasets is found in all cases, resulting in a picture of great simplicity, whereby the density and positioning of ROs explain the replication error rates for the entire range of eukaryotes for which data are available. The theory highlights three domains of error rates: negligible (yeast), tolerable (metazoan), and high (some plants), with the human genome at the extreme end of the middle domain.
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32
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Dimude JU, Midgley-Smith SL, Stein M, Rudolph CJ. Replication Termination: Containing Fork Fusion-Mediated Pathologies in Escherichia coli. Genes (Basel) 2016; 7:genes7080040. [PMID: 27463728 PMCID: PMC4999828 DOI: 10.3390/genes7080040] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/12/2016] [Accepted: 07/19/2016] [Indexed: 01/18/2023] Open
Abstract
Duplication of bacterial chromosomes is initiated via the assembly of two replication forks at a single defined origin. Forks proceed bi-directionally until they fuse in a specialised termination area opposite the origin. This area is flanked by polar replication fork pause sites that allow forks to enter but not to leave. The precise function of this replication fork trap has remained enigmatic, as no obvious phenotypes have been associated with its inactivation. However, the fork trap becomes a serious problem to cells if the second fork is stalled at an impediment, as replication cannot be completed, suggesting that a significant evolutionary advantage for maintaining this chromosomal arrangement must exist. Recently, we demonstrated that head-on fusion of replication forks can trigger over-replication of the chromosome. This over-replication is normally prevented by a number of proteins including RecG helicase and 3’ exonucleases. However, even in the absence of these proteins it can be safely contained within the replication fork trap, highlighting that multiple systems might be involved in coordinating replication fork fusions. Here, we discuss whether considering the problems associated with head-on replication fork fusion events helps us to better understand the important role of the replication fork trap in cellular metabolism.
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Affiliation(s)
- Juachi U Dimude
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK.
| | - Sarah L Midgley-Smith
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK.
| | - Monja Stein
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK.
| | - Christian J Rudolph
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK.
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33
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Knockleby J, Kim BJ, Mehta A, Lee H. Cdk1-mediated phosphorylation of Cdc7 suppresses DNA re-replication. Cell Cycle 2016; 15:1494-505. [PMID: 27105124 PMCID: PMC4934051 DOI: 10.1080/15384101.2016.1176658] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 03/23/2016] [Accepted: 04/06/2016] [Indexed: 12/18/2022] Open
Abstract
To maintain genetic stability, the entire mammalian genome must replicate only once per cell cycle. This is largely achieved by strictly regulating the stepwise formation of the pre-replication complex (pre-RC), followed by the activation of individual origins of DNA replication by Cdc7/Dbf4 kinase. However, the mechanism how Cdc7 itself is regulated in the context of cell cycle progression is poorly understood. Here we report that Cdc7 is phosphorylated by a Cdk1-dependent manner during prometaphase on multiple sites, resulting in its dissociation from origins. In contrast, Dbf4 is not removed from origins in prometaphase, nor is it degraded as cells exit mitosis. Our data thus demonstrates that constitutive phosphorylation of Cdc7 at Cdk1 recognition sites, but not the regulation of Dbf4, prevents the initiation of DNA replication in normally cycling cells and under conditions that promote re-replication in G2/M. As cells exit mitosis, PP1α associates with and dephosphorylates Cdc7. Together, our data support a model where Cdc7 (de)phosphorylation is the molecular switch for the activation and inactivation of DNA replication in mitosis, directly connecting Cdc7 and PP1α/Cdk1 to the regulation of once-per-cell cycle DNA replication in mammalian cells.
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Affiliation(s)
- James Knockleby
- Tumour Biology Group, Advanced Medical Research Institute of Canada, Health Sciences North, Sudbury, Ontario, Canada
| | - Byung Ju Kim
- Tumour Biology Group, Advanced Medical Research Institute of Canada, Health Sciences North, Sudbury, Ontario, Canada
| | - Avani Mehta
- Tumour Biology Group, Advanced Medical Research Institute of Canada, Health Sciences North, Sudbury, Ontario, Canada
| | - Hoyun Lee
- Tumour Biology Group, Advanced Medical Research Institute of Canada, Health Sciences North, Sudbury, Ontario, Canada
- Departments of Medicine, the Faculty of Medicine, the University of Ottawa, Ottawa, Ontario, Canada
- Northern Ontario School of Medicine, Sudbury, Ontario, Canada
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Khan SR, Mahaseth T, Kouzminova EA, Cronan GE, Kuzminov A. Static and Dynamic Factors Limit Chromosomal Replication Complexity in Escherichia coli, Avoiding Dangers of Runaway Overreplication. Genetics 2016; 202:945-60. [PMID: 26801182 PMCID: PMC4788131 DOI: 10.1534/genetics.115.184697] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 01/17/2016] [Indexed: 12/21/2022] Open
Abstract
We define chromosomal replication complexity (CRC) as the ratio of the copy number of the most replicated regions to that of unreplicated regions on the same chromosome. Although a typical CRC of eukaryotic or bacterial chromosomes is 2, rapidly growing Escherichia coli cells induce an extra round of replication in their chromosomes (CRC = 4). There are also E. coli mutants with stable CRC∼6. We have investigated the limits and consequences of elevated CRC in E. coli and found three limits: the "natural" CRC limit of ∼8 (cells divide more slowly); the "functional" CRC limit of ∼22 (cells divide extremely slowly); and the "tolerance" CRC limit of ∼64 (cells stop dividing). While the natural limit is likely maintained by the eclipse system spacing replication initiations, the functional limit might reflect the capacity of the chromosome segregation system, rather than dedicated mechanisms, and the tolerance limit may result from titration of limiting replication factors. Whereas recombinational repair is beneficial for cells at the natural and functional CRC limits, we show that it becomes detrimental at the tolerance CRC limit, suggesting recombinational misrepair during the runaway overreplication and giving a rationale for avoidance of the latter.
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Affiliation(s)
- Sharik R Khan
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Tulip Mahaseth
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Elena A Kouzminova
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Glen E Cronan
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Andrei Kuzminov
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
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35
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Sheu YJ, Kinney JB, Stillman B. Concerted activities of Mcm4, Sld3, and Dbf4 in control of origin activation and DNA replication fork progression. Genome Res 2016; 26:315-30. [PMID: 26733669 PMCID: PMC4772014 DOI: 10.1101/gr.195248.115] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 01/05/2016] [Indexed: 11/25/2022]
Abstract
Eukaryotic chromosomes initiate DNA synthesis from multiple replication origins in a temporally specific manner during S phase. The replicative helicase Mcm2-7 functions in both initiation and fork progression and thus is an important target of regulation. Mcm4, a helicase subunit, possesses an unstructured regulatory domain that mediates control from multiple kinase signaling pathways, including the Dbf4-dependent Cdc7 kinase (DDK). Following replication stress in S phase, Dbf4 and Sld3, an initiation factor and essential target of Cyclin-Dependent Kinase (CDK), are targets of the checkpoint kinase Rad53 for inhibition of initiation from origins that have yet to be activated, so-called late origins. Here, whole-genome DNA replication profile analysis is used to access under various conditions the effect of mutations that alter the Mcm4 regulatory domain and the Rad53 targets, Sld3 and Dbf4. Late origin firing occurs under genotoxic stress when the controls on Mcm4, Sld3, and Dbf4 are simultaneously eliminated. The regulatory domain of Mcm4 plays an important role in the timing of late origin firing, both in an unperturbed S phase and in dNTP limitation. Furthermore, checkpoint control of Sld3 impacts fork progression under replication stress. This effect is parallel to the role of the Mcm4 regulatory domain in monitoring fork progression. Hypomorph mutations in sld3 are suppressed by a mcm4 regulatory domain mutation. Thus, in response to cellular conditions, the functions executed by Sld3, Dbf4, and the regulatory domain of Mcm4 intersect to control origin firing and replication fork progression, thereby ensuring genome stability.
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Affiliation(s)
- Yi-Jun Sheu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Justin B Kinney
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Bruce Stillman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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36
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Archaeal DNA Replication Origins and Recruitment of the MCM Replicative Helicase. DNA REPLICATION ACROSS TAXA 2016; 39:169-90. [DOI: 10.1016/bs.enz.2016.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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37
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Swanson CI, Meserve JH, McCarter PC, Thieme A, Mathew T, Elston TC, Duronio RJ. Expression of an S phase-stabilized version of the CDK inhibitor Dacapo can alter endoreplication. Development 2015; 142:4288-98. [PMID: 26493402 DOI: 10.1242/dev.115006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 10/12/2015] [Indexed: 01/01/2023]
Abstract
In developing organisms, divergence from the canonical cell division cycle is often necessary to ensure the proper growth, differentiation, and physiological function of a variety of tissues. An important example is endoreplication, in which endocycling cells alternate between G and S phase without intervening mitosis or cytokinesis, resulting in polyploidy. Although significantly different from the canonical cell cycle, endocycles use regulatory pathways that also function in diploid cells, particularly those involved in S phase entry and progression. A key S phase regulator is the Cyclin E-Cdk2 kinase, which must alternate between periods of high (S phase) and low (G phase) activity in order for endocycling cells to achieve repeated rounds of S phase and polyploidy. The mechanisms that drive these oscillations of Cyclin E-Cdk2 activity are not fully understood. Here, we show that the Drosophila Cyclin E-Cdk2 inhibitor Dacapo (Dap) is targeted for destruction during S phase via a PIP degron, contributing to oscillations of Dap protein accumulation during both mitotic cycles and endocycles. Expression of a PIP degron mutant Dap attenuates endocycle progression but does not obviously affect proliferating diploid cells. A mathematical model of the endocycle predicts that the rate of destruction of Dap during S phase modulates the endocycle by regulating the length of G phase. We propose from this model and our in vivo data that endo S phase-coupled destruction of Dap reduces the threshold of Cyclin E-Cdk2 activity necessary to trigger the subsequent G-S transition, thereby influencing endocycle oscillation frequency and the extent of polyploidy.
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Affiliation(s)
- Christina I Swanson
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Joy H Meserve
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Patrick C McCarter
- Curriculum in Bioinformatics & Computational Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Alexis Thieme
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Tony Mathew
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Timothy C Elston
- Curriculum in Bioinformatics & Computational Biology, University of North Carolina, Chapel Hill, NC 27599, USA Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Robert J Duronio
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA
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38
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Graindorge D, Martineau S, Machon C, Arnoux P, Guitton J, Francesconi S, Frochot C, Sage E, Girard PM. Singlet Oxygen-Mediated Oxidation during UVA Radiation Alters the Dynamic of Genomic DNA Replication. PLoS One 2015; 10:e0140645. [PMID: 26485711 PMCID: PMC4618472 DOI: 10.1371/journal.pone.0140645] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 09/29/2015] [Indexed: 02/07/2023] Open
Abstract
UVA radiation (320–400 nm) is a major environmental agent that can exert its deleterious action on living organisms through absorption of the UVA photons by endogenous or exogenous photosensitizers. This leads to the production of reactive oxygen species (ROS), such as singlet oxygen (1O2) and hydrogen peroxide (H2O2), which in turn can modify reversibly or irreversibly biomolecules, such as lipids, proteins and nucleic acids. We have previously reported that UVA-induced ROS strongly inhibit DNA replication in a dose-dependent manner, but independently of the cell cycle checkpoints activation. Here, we report that the production of 1O2 by UVA radiation leads to a transient inhibition of replication fork velocity, a transient decrease in the dNTP pool, a quickly reversible GSH-dependent oxidation of the RRM1 subunit of ribonucleotide reductase and sustained inhibition of origin firing. The time of recovery post irradiation for each of these events can last from few minutes (reduction of oxidized RRM1) to several hours (replication fork velocity and origin firing). The quenching of 1O2 by sodium azide prevents the delay of DNA replication, the decrease in the dNTP pool and the oxidation of RRM1, while inhibition of Chk1 does not prevent the inhibition of origin firing. Although the molecular mechanism remains elusive, our data demonstrate that the dynamic of replication is altered by UVA photosensitization of vitamins via the production of singlet oxygen.
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Affiliation(s)
- Dany Graindorge
- CNRS UMR 3348, Stress Génotoxiques et Cancer, Orsay, France
- Curie Institute, PSL Research University, Orsay, France
| | - Sylvain Martineau
- CNRS UMR 3348, Stress Génotoxiques et Cancer, Orsay, France
- Curie Institute, PSL Research University, Orsay, France
| | - Christelle Machon
- Centre Hospitalier Lyon-Sud, Hospices Civils de Lyon, Laboratoire de biochimie-toxicologie, Pierre Bénite, France
- Laboratoire de chimie analytique, Université Lyon 1, ISPBL, Faculté de pharmacie, Lyon, France
| | - Philippe Arnoux
- Université de Lorraine, Laboratoire Réactions et Génie des Procédés (LRGP), Nancy, France
- CNRS, UMR7274, Nancy, France
| | - Jérôme Guitton
- Centre Hospitalier Lyon-Sud, Hospices Civils de Lyon, Laboratoire de biochimie-toxicologie, Pierre Bénite, France
- Laboratoire de Toxicologie, Université Lyon 1, ISPBL, Faculté de pharmacie, Lyon, France
| | - Stefania Francesconi
- CNRS UMR 3348, Stress Génotoxiques et Cancer, Orsay, France
- Curie Institute, PSL Research University, Orsay, France
| | - Céline Frochot
- Université de Lorraine, Laboratoire Réactions et Génie des Procédés (LRGP), Nancy, France
- CNRS, UMR7274, Nancy, France
| | - Evelyne Sage
- CNRS UMR 3348, Stress Génotoxiques et Cancer, Orsay, France
- Curie Institute, PSL Research University, Orsay, France
| | - Pierre-Marie Girard
- CNRS UMR 3348, Stress Génotoxiques et Cancer, Orsay, France
- Curie Institute, PSL Research University, Orsay, France
- * E-mail:
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39
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Macheret M, Halazonetis TD. DNA replication stress as a hallmark of cancer. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2015; 10:425-48. [PMID: 25621662 DOI: 10.1146/annurev-pathol-012414-040424] [Citation(s) in RCA: 510] [Impact Index Per Article: 56.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Human cancers share properties referred to as hallmarks, among which sustained proliferation, escape from apoptosis, and genomic instability are the most pervasive. The sustained proliferation hallmark can be explained by mutations in oncogenes and tumor suppressors that regulate cell growth, whereas the escape from apoptosis hallmark can be explained by mutations in the TP53, ATM, or MDM2 genes. A model to explain the presence of the three hallmarks listed above, as well as the patterns of genomic instability observed in human cancers, proposes that the genes driving cell proliferation induce DNA replication stress, which, in turn, generates genomic instability and selects for escape from apoptosis. Here, we review the data that support this model, as well as the mechanisms by which oncogenes induce replication stress. Further, we argue that DNA replication stress should be considered as a hallmark of cancer because it likely drives cancer development and is very prevalent.
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Affiliation(s)
- Morgane Macheret
- Department of Molecular Biology, University of Geneva, 1205 Geneva, Switzerland;
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40
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Lee JP, Liu C, Li T, Zhu G, Li X. Development of stapled helical peptides to perturb the Cdt1-Mcm6 interaction. J Pept Sci 2015; 21:593-8. [DOI: 10.1002/psc.2779] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 03/07/2015] [Accepted: 03/10/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Jonghan Peter Lee
- Department of Chemistry; The University of Hong Kong; Hong Kong China
| | - Changdong Liu
- Division of Life Science; The Hong Kong University of Sciences and Technology; Hong Kong China
| | - Tianlu Li
- Department of Chemistry; The University of Hong Kong; Hong Kong China
| | - Guang Zhu
- Division of Life Science; The Hong Kong University of Sciences and Technology; Hong Kong China
| | - Xuechen Li
- Department of Chemistry; The University of Hong Kong; Hong Kong China
- State Key Laboratory of Synthetic Chemistry; The University of Hong Kong; Hong Kong China
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Gentric G, Maillet V, Paradis V, Couton D, L'Hermitte A, Panasyuk G, Fromenty B, Celton-Morizur S, Desdouets C. Oxidative stress promotes pathologic polyploidization in nonalcoholic fatty liver disease. J Clin Invest 2015; 125:981-92. [PMID: 25621497 DOI: 10.1172/jci73957] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 12/15/2014] [Indexed: 12/13/2022] Open
Abstract
Polyploidization is one of the most dramatic changes that can occur in the genome. In the liver, physiological polyploidization events occur during both liver development and throughout adult life. Here, we determined that a pathological polyploidization takes place in nonalcoholic fatty liver disease (NAFLD), a widespread hepatic metabolic disorder that is believed to be a risk factor for hepatocellular carcinoma (HCC). In murine models of NAFLD, the parenchyma of fatty livers displayed alterations of the polyploidization process, including the presence of a large proportion of highly polyploid mononuclear cells, which are rarely observed in normal hepatic parenchyma. Biopsies from patients with nonalcoholic steatohepatitis (NASH) revealed the presence of alterations in hepatocyte ploidy compared with tissue from control individuals. Hepatocytes from NAFLD mice revealed that progression through the S/G2 phases of the cell cycle was inefficient. This alteration was associated with activation of a G2/M DNA damage checkpoint, which prevented activation of the cyclin B1/CDK1 complex. Furthermore, we determined that oxidative stress promotes the appearance of highly polyploid cells, and antioxidant-treated NAFLD hepatocytes resumed normal cell division and returned to a physiological state of polyploidy. Collectively, these findings indicate that oxidative stress promotes pathological polyploidization and suggest that this is an early event in NAFLD that may contribute to HCC development.
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42
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Richardson CD, Li JJ. Regulatory mechanisms that prevent re-initiation of DNA replication can be locally modulated at origins by nearby sequence elements. PLoS Genet 2014; 10:e1004358. [PMID: 24945837 PMCID: PMC4063666 DOI: 10.1371/journal.pgen.1004358] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 03/24/2014] [Indexed: 11/18/2022] Open
Abstract
Eukaryotic cells must inhibit re-initiation of DNA replication at each of the thousands of origins in their genome because re-initiation can generate genomic alterations with extraordinary frequency. To minimize the probability of re-initiation from so many origins, cells use a battery of regulatory mechanisms that reduce the activity of replication initiation proteins. Given the global nature of these mechanisms, it has been presumed that all origins are inhibited identically. However, origins re-initiate with diverse efficiencies when these mechanisms are disabled, and this diversity cannot be explained by differences in the efficiency or timing of origin initiation during normal S phase replication. This observation raises the possibility of an additional layer of replication control that can differentially regulate re-initiation at distinct origins. We have identified novel genetic elements that are necessary for preferential re-initiation of two origins and sufficient to confer preferential re-initiation on heterologous origins when the control of re-initiation is partially deregulated. The elements do not enhance the S phase timing or efficiency of adjacent origins and thus are specifically acting as re-initiation promoters (RIPs). We have mapped the two RIPs to ∼60 bp AT rich sequences that act in a distance- and sequence-dependent manner. During the induction of re-replication, Mcm2-7 reassociates both with origins that preferentially re-initiate and origins that do not, suggesting that the RIP elements can overcome a block to re-initiation imposed after Mcm2-7 associates with origins. Our findings identify a local level of control in the block to re-initiation. This local control creates a complex genomic landscape of re-replication potential that is revealed when global mechanisms preventing re-replication are compromised. Hence, if re-replication does contribute to genomic alterations, as has been speculated for cancer cells, some regions of the genome may be more susceptible to these alterations than others. Eukaryotic organisms have hundreds to thousands of DNA replication origins distributed throughout their genomes. Faithful duplication of these genomes requires a multitude of global controls that ensure that every replication origin initiates at most once per cell cycle. Disruptions in these controls can result in re-initiation of origins and localized re-replication of the surrounding genome. Such re-replicated genomic segments are converted to stable chromosomal alterations with extraordinarily efficiency and could provide a potential source of genomic alterations associated with cancer cells. This publication establishes the existence of a local layer of replication control by identifying new genetic elements, termed re-initiation promoters (RIPs) that can locally override some of the global mechanisms preventing re-initiation. Origins adjacent to RIP elements are not as tightly controlled and thus more susceptible to re-initiation, especially when these global controls are compromised. We speculate that RIP elements contribute to genomic variability in origin control and make some regions of the genome more susceptible to re-replication induced genomic instability.
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Affiliation(s)
- Christopher D. Richardson
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
| | - Joachim J. Li
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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Bellelli R, Castellone MD, Guida T, Limongello R, Dathan NA, Merolla F, Cirafici AM, Affuso A, Masai H, Costanzo V, Grieco D, Fusco A, Santoro M, Carlomagno F. NCOA4 transcriptional coactivator inhibits activation of DNA replication origins. Mol Cell 2014; 55:123-37. [PMID: 24910095 DOI: 10.1016/j.molcel.2014.04.031] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Revised: 03/31/2014] [Accepted: 04/28/2014] [Indexed: 11/19/2022]
Abstract
NCOA4 is a transcriptional coactivator of nuclear hormone receptors that undergoes gene rearrangement in human cancer. By combining studies in Xenopus laevis egg extracts and mouse embryonic fibroblasts (MEFs), we show here that NCOA4 is a minichromosome maintenance 7 (MCM7)-interacting protein that is able to control DNA replication. Depletion-reconstitution experiments in Xenopus laevis egg extracts indicate that NCOA4 acts as an inhibitor of DNA replication origin activation by regulating CMG (CDC45/MCM2-7/GINS) helicase. NCOA4(-/-) MEFs display unscheduled origin activation and reduced interorigin distance; this results in replication stress, as shown by the presence of fork stalling, reduction of fork speed, and premature senescence. Together, our findings indicate that NCOA4 acts as a regulator of DNA replication origins that helps prevent inappropriate DNA synthesis and replication stress.
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Affiliation(s)
- Roberto Bellelli
- Istituto di Endocrinologia ed Oncologia Sperimentale del CNR/Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli "Federico II," 80131 Naples, Italy
| | - Maria Domenica Castellone
- Istituto di Endocrinologia ed Oncologia Sperimentale del CNR/Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli "Federico II," 80131 Naples, Italy
| | - Teresa Guida
- Istituto di Endocrinologia ed Oncologia Sperimentale del CNR/Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli "Federico II," 80131 Naples, Italy
| | - Roberto Limongello
- Istituto di Endocrinologia ed Oncologia Sperimentale del CNR/Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli "Federico II," 80131 Naples, Italy
| | | | - Francesco Merolla
- Istituto di Endocrinologia ed Oncologia Sperimentale del CNR/Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli "Federico II," 80131 Naples, Italy
| | - Anna Maria Cirafici
- Istituto di Endocrinologia ed Oncologia Sperimentale del CNR/Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli "Federico II," 80131 Naples, Italy
| | - Andrea Affuso
- Animal Model Facility, Biogem s.c.a.r.l., 83031 Ariano Irpino, Avellino, Italy
| | - Hisao Masai
- Tokyo Metropolitan Institute of Medical Sciences, 156-8506 Tokyo, Japan
| | - Vincenzo Costanzo
- London Research Institute, Clare Hall Laboratories, Blanche Lane, South Mimms EN6 3LD, UK
| | - Domenico Grieco
- Istituto di Endocrinologia ed Oncologia Sperimentale del CNR/Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli "Federico II," 80131 Naples, Italy
| | - Alfredo Fusco
- Istituto di Endocrinologia ed Oncologia Sperimentale del CNR/Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli "Federico II," 80131 Naples, Italy
| | - Massimo Santoro
- Istituto di Endocrinologia ed Oncologia Sperimentale del CNR/Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli "Federico II," 80131 Naples, Italy.
| | - Francesca Carlomagno
- Istituto di Endocrinologia ed Oncologia Sperimentale del CNR/Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli "Federico II," 80131 Naples, Italy.
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44
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Tsuchiya D, Yang Y, Lacefield S. Positive feedback of NDT80 expression ensures irreversible meiotic commitment in budding yeast. PLoS Genet 2014; 10:e1004398. [PMID: 24901499 PMCID: PMC4046916 DOI: 10.1371/journal.pgen.1004398] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 04/03/2014] [Indexed: 01/03/2023] Open
Abstract
In budding yeast, meiotic commitment is the irreversible continuation of the developmental path of meiosis. After reaching meiotic commitment, cells finish meiosis and gametogenesis, even in the absence of the meiosis-inducing signal. In contrast, if the meiosis-inducing signal is removed and the mitosis-inducing signal is provided prior to reaching meiotic commitment, cells exit meiosis and return to mitosis. Previous work has shown that cells commit to meiosis after prophase I but before entering the meiotic divisions. Since the Ndt80 transcription factor induces expression of middle meiosis genes necessary for the meiotic divisions, we examined the role of the NDT80 transcriptional network in meiotic commitment. Using a microfluidic approach to analyze single cells, we found that cells commit to meiosis in prometaphase I, after the induction of the Ndt80-dependent genes. Our results showed that high-level expression of NDT80 is important for the timing and irreversibility of meiotic commitment. A modest reduction in NDT80 levels delayed meiotic commitment based on meiotic stages, although the timing of each meiotic stage was similar to that of wildtype cells. A further reduction of NDT80 resulted in the surprising finding of inappropriately uncommitted cells: withdrawal of the meiosis-inducing signal and addition of the mitosis-inducing signal to cells at stages beyond metaphase I caused return to mitosis, leading to multi-nucleate cells. Since Ndt80 enhances its own transcription through positive feedback, we tested whether positive feedback ensured the irreversibility of meiotic commitment. Ablating positive feedback in NDT80 expression resulted in a complete loss of meiotic commitment. These findings suggest that irreversibility of meiotic commitment is a consequence of the NDT80 transcriptional positive feedback loop, which provides the high-level of Ndt80 required for the developmental switch of meiotic commitment. These results also illustrate the importance of irreversible meiotic commitment for maintaining genome integrity by preventing formation of multi-nucleate cells.
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Affiliation(s)
- Dai Tsuchiya
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Yang Yang
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Soni Lacefield
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
- * E-mail:
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Raynaud C, Mallory AC, Latrasse D, Jégu T, Bruggeman Q, Delarue M, Bergounioux C, Benhamed M. Chromatin meets the cell cycle. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2677-89. [PMID: 24497647 DOI: 10.1093/jxb/ert433] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The cell cycle is one of the most comprehensively studied biological processes, due primarily to its significance in growth and development, and its deregulation in many human disorders. Studies using a diverse set of model organisms, including yeast, worms, flies, frogs, mammals, and plants, have greatly expanded our knowledge of the cell cycle and have contributed to the universally accepted view of how the basic cell cycle machinery is regulated. In addition to the oscillating activity of various cyclin-dependent kinase (CDK)-cyclin complexes, a plethora of proteins affecting various aspects of chromatin dynamics has been shown to be essential for cell proliferation during plant development. Furthermore, it was reported recently that core cell cycle regulators control gene expression by modifying histone patterns. This review focuses on the intimate relationship between the cell cycle and chromatin. It describes the dynamics and functions of chromatin structures throughout cell cycle progression and discusses the role of heterochromatin as a barrier against re-replication and endoreduplication. It also proposes that core plant cell cycle regulators control gene expression in a manner similar to that described in mammals. At present, our challenge in plants is to define the complete set of effectors and actors that coordinate cell cycle progression and chromatin structure and to understand better the functional interplay between these two processes.
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Affiliation(s)
- Cécile Raynaud
- Institut de Biologie des Plantes, UMR8618 Université Paris-Sud XI, 91405 Orsay, France
| | - Allison C Mallory
- Institut de Biologie des Plantes, UMR8618 Université Paris-Sud XI, 91405 Orsay, France
| | - David Latrasse
- Institut de Biologie des Plantes, UMR8618 Université Paris-Sud XI, 91405 Orsay, France
| | - Teddy Jégu
- Institut de Biologie des Plantes, UMR8618 Université Paris-Sud XI, 91405 Orsay, France
| | - Quentin Bruggeman
- Institut de Biologie des Plantes, UMR8618 Université Paris-Sud XI, 91405 Orsay, France
| | - Marianne Delarue
- Institut de Biologie des Plantes, UMR8618 Université Paris-Sud XI, 91405 Orsay, France
| | - Catherine Bergounioux
- Institut de Biologie des Plantes, UMR8618 Université Paris-Sud XI, 91405 Orsay, France
| | - Moussa Benhamed
- Institut de Biologie des Plantes, UMR8618 Université Paris-Sud XI, 91405 Orsay, France
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Benkemoun L, Descoteaux C, Chartier NT, Pintard L, Labbé JC. PAR-4/LKB1 regulates DNA replication during asynchronous division of the early C. elegans embryo. ACTA ACUST UNITED AC 2014; 205:447-55. [PMID: 24841566 PMCID: PMC4033775 DOI: 10.1083/jcb.201312029] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
DNA replication is asymmetrically regulated in the two-cell stage C. elegans embryo by the PAR-4 and PAR-1 polarity proteins, which function independently of known regulators of cell cycle timing to dampen DNA replication dynamics specifically in the posterior blastomere. Regulation of cell cycle duration is critical during development, yet the underlying molecular mechanisms are still poorly understood. The two-cell stage Caenorhabditis elegans embryo divides asynchronously and thus provides a powerful context in which to study regulation of cell cycle timing during development. Using genetic analysis and high-resolution imaging, we found that deoxyribonucleic acid (DNA) replication is asymmetrically regulated in the two-cell stage embryo and that the PAR-4 and PAR-1 polarity proteins dampen DNA replication dynamics specifically in the posterior blastomere, independently of regulators previously implicated in the control of cell cycle timing. Our results demonstrate that accurate control of DNA replication is crucial during C. elegans early embryonic development and further provide a novel mechanism by which PAR proteins control cell cycle progression during asynchronous cell division.
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Affiliation(s)
- Laura Benkemoun
- Cell Division and Differentiation Laboratory, Institute of Research in Immunology and Cancer, and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Catherine Descoteaux
- Cell Division and Differentiation Laboratory, Institute of Research in Immunology and Cancer, and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Nicolas T Chartier
- Cell Division and Differentiation Laboratory, Institute of Research in Immunology and Cancer, and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Lionel Pintard
- Institut Jacques Monod, Centre National de la Recherche Scientifique and Université Paris Diderot, F-75013 Paris, France
| | - Jean-Claude Labbé
- Cell Division and Differentiation Laboratory, Institute of Research in Immunology and Cancer, and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Québec H3T 1J4, CanadaCell Division and Differentiation Laboratory, Institute of Research in Immunology and Cancer, and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Québec H3T 1J4, Canada
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47
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Abstract
While large portions of the mammalian genome are known to replicate sequentially in a distinct, tissue-specific order, recent studies suggest that the inactive X chromosome is duplicated rapidly via random, synchronous DNA synthesis at numerous adjacent regions. The rapid duplication of the inactive X chromosome was observed in high-resolution studies visualizing DNA replication patterns in the nucleus, and by allele-specific DNA sequencing studies measuring the extent of DNA synthesis. These studies conclude that inactive X chromosomes complete replication earlier than previously thought and suggest that the strict order of DNA replication detected in the majority of genomic regions is not preserved in non-transcribed, "silent" chromatin. These observations alter current concepts about the regulation of DNA replication in non-transcribed portions of the genome in general and in the inactive X-chromosome in particular.
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Affiliation(s)
- Mirit I Aladjem
- Developmental Therapeutic Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
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48
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Abstract
Evolutionary selection for optimal genome preservation, replication, and expression should yield similar chromosome organizations in any type of cells. And yet, the chromosome organization is surprisingly different between eukaryotes and prokaryotes. The nuclear versus cytoplasmic accommodation of genetic material accounts for the distinct eukaryotic and prokaryotic modes of genome evolution, but it falls short of explaining the differences in the chromosome organization. I propose that the two distinct ways to organize chromosomes are driven by the differences between the global-consecutive chromosome cycle of eukaryotes and the local-concurrent chromosome cycle of prokaryotes. Specifically, progressive chromosome segregation in prokaryotes demands a single duplicon per chromosome, while other "precarious" features of the prokaryotic chromosomes can be viewed as compensations for this severe restriction.
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49
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Gros J, Devbhandari S, Remus D. Origin plasticity during budding yeast DNA replication in vitro. EMBO J 2014; 33:621-36. [PMID: 24566988 DOI: 10.1002/embj.201387278] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The separation of DNA replication origin licensing and activation in the cell cycle is essential for genome stability across generations in eukaryotic cells. Pre-replicative complexes (pre-RCs) license origins by loading Mcm2-7 complexes in inactive form around DNA. During origin firing in S phase, replisomes assemble around the activated Mcm2-7 DNA helicase. Budding yeast pre-RCs have previously been reconstituted in vitro with purified proteins. Here, we show that reconstituted pre-RCs support replication of plasmid DNA in yeast cell extracts in a reaction that exhibits hallmarks of cellular replication initiation. Plasmid replication in vitro results in the generation of covalently closed circular daughter molecules, indicating that the system recapitulates the initiation, elongation, and termination stages of DNA replication. Unexpectedly, yeast origin DNA is not strictly required for DNA replication in vitro, as heterologous DNA sequences could support replication of plasmid molecules. Our findings support the notion that epigenetic mechanisms are important for determining replication origin sites in budding yeast, highlighting mechanistic principles of replication origin specification that are common among eukaryotes.
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Affiliation(s)
- Julien Gros
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
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50
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Kaur G, Vora MP, Czerwonka CA, Rozgaja TA, Grimwade JE, Leonard AC. Building the bacterial orisome: high-affinity DnaA recognition plays a role in setting the conformation of oriC DNA. Mol Microbiol 2014; 91:1148-63. [PMID: 24443848 DOI: 10.1111/mmi.12525] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2014] [Indexed: 11/29/2022]
Abstract
During assembly of the E. coli pre-replicative complex (pre-RC), initiator DnaA oligomers are nucleated from three widely separated high-affinity DnaA recognition sites in oriC. Oligomer assembly is then guided by low-affinity DnaA recognition sites, but is also regulated by a switch-like conformational change in oriC mediated by sequential binding of two DNA bending proteins, Fis and IHF, serving as inhibitor and activator respectively. Although their recognition sites are separated by up to 90 bp, Fis represses IHF binding and weak DnaA interactions until accumulating DnaA displaces Fis from oriC. It remains unclear whether high-affinity DnaA binding plays any role in Fis repression at a distance and it is also not known whether all high-affinity DnaA recognition sites play an equivalent role in oligomer formation. To examine these issues, we developed origin-selective recombineering methods to mutate E. coli chromosomal oriC. We found that, although oligomers were assembled in the absence of any individual high-affinity DnaA binding site, loss of DnaA binding at peripheral sites eliminated Fis repression, and made binding of both Fis and IHF essential. We propose a model in which interaction of DnaA molecules at high-affinity sites regulates oriC DNA conformation.
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Affiliation(s)
- Gulpreet Kaur
- Department of Biological Sciences, Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL, 32901, USA
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