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Saif A, Islam MT, Raihan MO, Yousefi N, Rahman MA, Faridi H, Hasan AR, Hossain MM, Saleem RM, Albadrani GM, Al-Ghadi MQ, Ahasan Setu MA, Kamel M, Abdel-Daim MM, Aktaruzzaman M. Pan-cancer analysis of CDC7 in human tumors: Integrative multi-omics insights and discovery of novel marine-based inhibitors through machine learning and computational approaches. Comput Biol Med 2025; 190:110044. [PMID: 40120182 DOI: 10.1016/j.compbiomed.2025.110044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2024] [Revised: 03/14/2025] [Accepted: 03/16/2025] [Indexed: 03/25/2025]
Abstract
Cancer remains a significant global health challenge, with the Cell Division Cycle 7 (CDC7) protein emerging as a potential therapeutic target due to its critical role in tumor proliferation, survival, and resistance. However, a comprehensive analysis of CDC7 across multiple cancers is lacking, and existing therapeutic options have come with limited clinical success. The aim of this is to integrate a comprehensive pan-cancer analysis of CDC7 with the identification of novel marine-derived inhibitors, bridging the understanding of CDC7's role as a prognostic biomarker and therapeutic target across diverse cancer types. In this study, we conducted a pan-cancer analysis of CDC7 across 33 tumor types using publicly available datasets to evaluate its expression, genetic alterations, immune interactions, survival, and prognostic significance. Additionally, a marine-derived compound library of 31,492 molecules was screened to identify potential CDC7 inhibitors using chemoinformatics and machine learning. The top candidates underwent rigorous evaluations, including molecular docking, pharmacokinetics, toxicity, Density Functional Theory (DFT) calculations, and Molecular Dynamics (MD) simulations. The findings revealed that CDC7 is overexpressed in several cancers and is associated with poor survival outcomes and unfavorable prognosis. Enrichment analysis linked CDC7 to critical DNA replication pathways, while its role in modulating tumor-immune interactions highlighted its potential as a target for immunotherapy. Among all tested compounds, Tetrahydroaltersolanol D (CMNPD21999) exhibited the strongest binding affinity and stability, along with better drug-likeness and zero toxicity. These attributes highlight its potential as a promising drug candidate for CDC7 inhibition and future cancer treatment development. Furthermore, additional in vitro and in vivo studies are required to confirm the effectiveness of this drug candidate against the CDC7 protein.
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Affiliation(s)
- Ahmed Saif
- Department of Pharmacy, Faculty of Science, University of Rajshahi, Rajshahi, 6205, Bangladesh; Laboratory of Advanced Computational Biology, Biological Research on the Brain (BRB), Jashore, 7408, Bangladesh.
| | - Md Tarikul Islam
- Department of Genetic Engineering and Biotechnology, Faculty of Biological Science and Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh; Laboratory of Advanced Computational Biology, Biological Research on the Brain (BRB), Jashore, 7408, Bangladesh.
| | - Md Obayed Raihan
- Laboratory of Advanced Computational Biology, Biological Research on the Brain (BRB), Jashore, 7408, Bangladesh; Department of Pharmaceutical Sciences, College of Health Sciences and Pharmacy, Chicago State University, Chicago, IL, USA.
| | - Niloofar Yousefi
- Department of Industrial Engineering and Management Systems, University of Central Florida, USA, Orlando, FL, USA
| | - Md Ajijur Rahman
- Department of Pharmacy, Faculty of Science, University of Rajshahi, Rajshahi, 6205, Bangladesh
| | - Hafeez Faridi
- Department of Pharmaceutical Sciences, College of Health Sciences and Pharmacy, Chicago State University, Chicago, IL, USA
| | - Al Riyad Hasan
- Laboratory of Advanced Computational Biology, Biological Research on the Brain (BRB), Jashore, 7408, Bangladesh; Department of Pharmacy, Faculty of Biological Science and Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh
| | - Mirza Mahfuj Hossain
- Laboratory of Advanced Computational Biology, Biological Research on the Brain (BRB), Jashore, 7408, Bangladesh; Department of Computer Science and Engineering, Faculty of Engineering and Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh
| | - Rasha Mohammed Saleem
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Al-Baha University, Al-Baha, 65431, Saudi Arabia
| | - Ghadeer M Albadrani
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, 84428, Riyadh, 11671, Saudi Arabia
| | - Muath Q Al-Ghadi
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia
| | - Md Ali Ahasan Setu
- Laboratory of Advanced Computational Biology, Biological Research on the Brain (BRB), Jashore, 7408, Bangladesh; Department of Microbiology, Faculty of Biological Science and Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh
| | - Mohamed Kamel
- Department of Medicine and Infectious Diseases, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
| | - Mohamed M Abdel-Daim
- Department of Pharmaceutical Sciences, Pharmacy Program, Batterjee Medical College, P.O. Box 6231, Jeddah, 21442, Saudi Arabia; Pharmacology Department, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, 41522, Egypt
| | - Md Aktaruzzaman
- Laboratory of Advanced Computational Biology, Biological Research on the Brain (BRB), Jashore, 7408, Bangladesh; Department of Pharmacy, Faculty of Biological Science and Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh.
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2
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Damasceno JD, Briggs EM, Krasilnikova M, Marques CA, Lapsley C, McCulloch R. R-loops acted on by RNase H1 influence DNA replication timing and genome stability in Leishmania. Nat Commun 2025; 16:1470. [PMID: 39922816 PMCID: PMC11807225 DOI: 10.1038/s41467-025-56785-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Accepted: 01/31/2025] [Indexed: 02/10/2025] Open
Abstract
Genomes in eukaryotes normally undergo DNA replication in a choreographed temporal order, resulting in early and late replicating chromosome compartments. Leishmania, a human protozoan parasite, displays an unconventional DNA replication program in which the timing of DNA replication completion is chromosome size-dependent: larger chromosomes complete replication later then smaller ones. Here we show that both R-loops and RNase H1, a ribonuclease that resolves RNA-DNA hybrids, accumulate in Leishmania major chromosomes in a pattern that reflects their replication timing. Furthermore, we demonstrate that such differential organisation of R-loops, RNase H1 and DNA replication timing across the parasite's chromosomes correlates with size-dependent differences in chromatin accessibility, G quadruplex distribution and sequence content. Using conditional gene excision, we show that loss of RNase H1 leads to transient growth perturbation and permanently abrogates the differences in DNA replication timing across chromosomes, as well as altering levels of aneuploidy and increasing chromosome instability in a size-dependent manner. This work provides a link between R-loop homeostasis and DNA replication timing in a eukaryotic parasite and demonstrates that orchestration of DNA replication dictates levels of genome plasticity in Leishmania.
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Affiliation(s)
- Jeziel D Damasceno
- The University of Glasgow Centre for Parasitology, The Wellcome Centre for Integrative Parasitology, University of Glasgow, School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK.
| | - Emma M Briggs
- University of Edinburgh, Institute for Immunology and Infection Research, School of Biological Sciences, Edinburgh, UK
- Biosciences Institute, Cookson Building, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Marija Krasilnikova
- The University of Glasgow Centre for Parasitology, The Wellcome Centre for Integrative Parasitology, University of Glasgow, School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Catarina A Marques
- The University of Glasgow Centre for Parasitology, The Wellcome Centre for Integrative Parasitology, University of Glasgow, School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Craig Lapsley
- The University of Glasgow Centre for Parasitology, The Wellcome Centre for Integrative Parasitology, University of Glasgow, School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Richard McCulloch
- The University of Glasgow Centre for Parasitology, The Wellcome Centre for Integrative Parasitology, University of Glasgow, School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK.
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3
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Trakroo D, Agarwal P, Alekar A, Ghosh SK. Nonessential kinetochore proteins contribute to meiotic chromosome condensation through polo-like kinase. Mol Biol Cell 2025; 36:ar14. [PMID: 39705398 PMCID: PMC11809314 DOI: 10.1091/mbc.e24-08-0348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2024] [Revised: 11/12/2024] [Accepted: 12/10/2024] [Indexed: 12/22/2024] Open
Abstract
Chromosome condensation plays a pivotal role during faithful chromosome segregation, hence, understanding the factors that drive condensation is crucial to get mechanistic insight into chromosome segregation. Previously, we showed that in budding yeast, the absence of the nonessential kinetochore proteins affects chromatin-condensin association in meiosis but not in mitosis. A differential organization of the kinetochores, that we and others observed earlier during mitosis and meiosis may contribute to the meiotic-specific role. Here, with our in-depth investigation using in vivo chromosome condensation assays in cells lacking a nonessential kinetochore protein, Ctf19, we establish that these proteins have roles in achieving a higher meiotic condensation without influencing much of the mitotic condensation. We further observed an accumulation of the polo-like kinase Cdc5 owing to its higher protein stability in ctf19Δ meiotic cells. High Cdc5 activity causes hyperphosphorylation of the condensin resulting in its reduced stability and concomitant decreased association with the chromatin. Overall, our findings highlight the role of Ctf19 in promoting meiotic chromosome condensation by influencing the activity of Cdc5 and thereby affecting the stability and association of condensin with the chromatin.
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Affiliation(s)
- Deepika Trakroo
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India
| | - Prakhar Agarwal
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India
| | - Anushka Alekar
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India
| | - Santanu Kumar Ghosh
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India
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4
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Krasiļņikova M, Marques CA, Briggs EM, Lapsley C, Hamilton G, Beraldi D, Crouch K, McCulloch R. Nanopore sequencing reveals that DNA replication compartmentalisation dictates genome stability and instability in Trypanosoma brucei. Nat Commun 2025; 16:751. [PMID: 39820334 PMCID: PMC11739655 DOI: 10.1038/s41467-025-56087-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Accepted: 01/07/2025] [Indexed: 01/19/2025] Open
Abstract
The Trypanosoma brucei genome is structurally complex. Eleven megabase-sized chromosomes each comprise a transcribed core flanked by silent subtelomeres, housing thousands of Variant Surface Glycoprotein (VSG) genes. Additionally, hundreds of sub-megabase chromosomes contain 177 bp repeats of unknown function, and VSG transcription sites localise to many telomeres. DNA replication dynamics have only been described in the megabase chromosome cores, and in the single active VSG transcription site. Using a Nanopore genome assembly, we show that megabase chromosome subtelomeres display a paucity of replication initiation events relative to the core, correlating with increased instability. In addition, replication of the active VSG transcription site is shown to originate from the telomere, likely causing targeted VSG recombination. Lastly, we provide evidence that the 177 bp repeats act as conserved DNA replication origins, explaining submegabase chromosome stability. Compartmentalized DNA replication therefore explains how T. brucei balances stable genome transmission with localised instability driving immune evasion.
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Affiliation(s)
- Marija Krasiļņikova
- University of Glasgow Centre for Parasitology, The Wellcome Centre for Integrative Parasitology, University of Glasgow, School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, United Kingdom
| | - Catarina A Marques
- University of Glasgow Centre for Parasitology, The Wellcome Centre for Integrative Parasitology, University of Glasgow, School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, United Kingdom.
| | - Emma M Briggs
- University of Glasgow Centre for Parasitology, The Wellcome Centre for Integrative Parasitology, University of Glasgow, School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, United Kingdom
- University of Edinburgh, Institute for Immunology and Infection Research, School of Biological Sciences, Edinburgh, United Kingdom
- Biosciences Institute, Cookson Building, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Craig Lapsley
- University of Glasgow Centre for Parasitology, The Wellcome Centre for Integrative Parasitology, University of Glasgow, School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, United Kingdom
| | - Graham Hamilton
- MVLS Research Facilities, University of Glasgow, Wolfson Wohl Cancer Research Centre, Garscube Estate, Switchback Rd, Bearsden, Glasgow, G61 1QH, United Kingdom
| | - Dario Beraldi
- University of Glasgow Centre for Parasitology, The Wellcome Centre for Integrative Parasitology, University of Glasgow, School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, United Kingdom
| | - Kathryn Crouch
- University of Glasgow Centre for Parasitology, The Wellcome Centre for Integrative Parasitology, University of Glasgow, School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, United Kingdom
| | - Richard McCulloch
- University of Glasgow Centre for Parasitology, The Wellcome Centre for Integrative Parasitology, University of Glasgow, School of Infection and Immunity, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, United Kingdom.
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5
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Theulot B, Tourancheau A, Simonin Chavignier E, Jean E, Arbona JM, Audit B, Hyrien O, Lacroix L, Le Tallec B. Telomere-to-telomere DNA replication timing profiling using single-molecule sequencing with Nanotiming. Nat Commun 2025; 16:242. [PMID: 39747057 PMCID: PMC11696806 DOI: 10.1038/s41467-024-55520-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Accepted: 12/13/2024] [Indexed: 01/04/2025] Open
Abstract
Current temporal studies of DNA replication are either low-resolution or require complex cell synchronisation and/or sorting procedures. Here we introduce Nanotiming, a single-molecule, nanopore sequencing-based method producing high-resolution, telomere-to-telomere replication timing (RT) profiles of eukaryotic genomes by interrogating changes in intracellular dTTP concentration during S phase through competition with its analogue bromodeoxyuridine triphosphate (BrdUTP) for incorporation into replicating DNA. This solely demands the labelling of asynchronously growing cells with an innocuous dose of BrdU during one doubling time followed by BrdU quantification along nanopore reads. We demonstrate in S. cerevisiae model eukaryote that Nanotiming reproduces RT profiles generated by reference methods both in wild-type and mutant cells inactivated for known RT determinants. Nanotiming is simple, accurate, inexpensive, amenable to large-scale analyses, and has the unique ability to access RT of individual telomeres, revealing that Rif1 iconic telomere regulator selectively delays replication of telomeres associated with specific subtelomeric elements.
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Affiliation(s)
- Bertrand Theulot
- IBENS, Département de biologie, École normale supérieure, Université PSL, CNRS, INSERM, 75005, Paris, France
- Sorbonne Université, Collège Doctoral, 75005, Paris, France
- Bertrand Theulot, Department of Biology, New York University, 100 Washington Square East, New York, NY, 10003, USA
| | - Alan Tourancheau
- IBENS, Département de biologie, École normale supérieure, Université PSL, CNRS, INSERM, 75005, Paris, France
| | - Emma Simonin Chavignier
- IBENS, Département de biologie, École normale supérieure, Université PSL, CNRS, INSERM, 75005, Paris, France
| | - Etienne Jean
- IBENS, Département de biologie, École normale supérieure, Université PSL, CNRS, INSERM, 75005, Paris, France
| | - Jean-Michel Arbona
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS, UMR5239, INSERM, U1293, Université Claude Bernard Lyon 1, 46 allée d'Italie, 69364, Lyon, France
- Jean-Michel Arbona, IBDM, UMR7288, Case 907, Parc Scientifique de Luminy, 13288, Marseille, Cedex 9, France
| | - Benjamin Audit
- CNRS, ENS de Lyon, LPENSL, UMR5672, 69342, Lyon, cedex 07, France
| | - Olivier Hyrien
- IBENS, Département de biologie, École normale supérieure, Université PSL, CNRS, INSERM, 75005, Paris, France
| | - Laurent Lacroix
- IBENS, Département de biologie, École normale supérieure, Université PSL, CNRS, INSERM, 75005, Paris, France
| | - Benoît Le Tallec
- IBENS, Département de biologie, École normale supérieure, Université PSL, CNRS, INSERM, 75005, Paris, France.
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Hoggard T, Chacin E, Hollatz AJ, Kurat CF, Fox CA. The budding yeast Fkh1 Forkhead associated (FHA) domain promotes a G1-chromatin state and the activity of chromosomal DNA replication origins. PLoS Genet 2024; 20:e1011366. [PMID: 39102423 PMCID: PMC11326605 DOI: 10.1371/journal.pgen.1011366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 08/15/2024] [Accepted: 07/09/2024] [Indexed: 08/07/2024] Open
Abstract
In Saccharomyces cerevisiae, the forkhead (Fkh) transcription factor Fkh1 (forkhead homolog) enhances the activity of many DNA replication origins that act in early S-phase (early origins). Current models posit that Fkh1 acts directly to promote these origins' activity by binding to origin-adjacent Fkh1 binding sites (FKH sites). However, the post-DNA binding functions that Fkh1 uses to promote early origin activity are poorly understood. Fkh1 contains a conserved FHA (forkhead associated) domain, a protein-binding module with specificity for phosphothreonine (pT)-containing partner proteins. At a small subset of yeast origins, the Fkh1-FHA domain enhances the ORC (origin recognition complex)-origin binding step, the G1-phase event that initiates the origin cycle. However, the importance of the Fkh1-FHA domain to either chromosomal replication or ORC-origin interactions at genome scale is unclear. Here, S-phase SortSeq experiments were used to compare genome replication in proliferating FKH1 and fkh1-R80A mutant cells. The Fkh1-FHA domain promoted the activity of ≈ 100 origins that act in early to mid- S-phase, including the majority of centromere-associated origins, while simultaneously inhibiting ≈ 100 late origins. Thus, in the absence of a functional Fkh1-FHA domain, the temporal landscape of the yeast genome was flattened. Origins are associated with a positioned nucleosome array that frames a nucleosome depleted region (NDR) over the origin, and ORC-origin binding is necessary but not sufficient for this chromatin organization. To ask whether the Fkh1-FHA domain had an impact on this chromatin architecture at origins, ORC ChIPSeq data generated from proliferating cells and MNaseSeq data generated from G1-arrested and proliferating cell populations were assessed. Origin groups that were differentially regulated by the Fkh1-FHA domain were characterized by distinct effects of this domain on ORC-origin binding and G1-phase chromatin. Thus, the Fkh1-FHA domain controlled the distinct chromatin architecture at early origins in G1-phase and regulated origin activity in S-phase.
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Affiliation(s)
- Timothy Hoggard
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Erika Chacin
- Biomedical Center Munich (BMC), Division of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, Martinsried, Germany
| | - Allison J Hollatz
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, United States of America
- Integrated Program in Biochemistry, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Christoph F Kurat
- Biomedical Center Munich (BMC), Division of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, Martinsried, Germany
| | - Catherine A Fox
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, United States of America
- Integrated Program in Biochemistry, University of Wisconsin, Madison, Wisconsin, United States of America
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7
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Cazzaniga C, Göder A, Rainey MD, Quinlan A, Coughlan S, Bernard S, Santocanale C. CDC7 inhibition drives an inflammatory response and a p53-dependent senescent-like state in breast epithelial cells. FEBS J 2024; 291:3147-3168. [PMID: 38555567 DOI: 10.1111/febs.17127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 02/04/2024] [Accepted: 03/18/2024] [Indexed: 04/02/2024]
Abstract
Drugs that block DNA replication prevent cell proliferation, which may result in anticancer activity. The latter is dependent on the drug's mode of action as well as on cell type-dependent responses to treatment. The inhibition of Cell division cycle 7-related protein kinase (CDC7), a key regulator of DNA replication, decreases the efficiency of origin firing and hampers the restarting of paused replication forks. Here, we show that upon prolonged CDC7 inhibition, breast-derived MCF10A cells progressively withdraw from the cell cycle and enter a reversible senescent-like state. This is characterised by the rewiring of the transcriptional programme with the induction of cytokine and chemokine expression and correlates with the accumulation of Cyclic GMP-AMP synthase (cGAS)-positive micronuclei. Importantly, cell fate depends on Cellular tumour antigen p53 (p53) function as cells no longer enter senescence but are funnelled into apoptosis upon p53 knockout. This work uncovers key features of the secondary response to CDC7 inhibitors, which could aid the development of these compounds as anticancer drugs.
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Affiliation(s)
- Chiara Cazzaniga
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, University of Galway, Ireland
| | - Anja Göder
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, University of Galway, Ireland
| | - Michael David Rainey
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, University of Galway, Ireland
| | - Aisling Quinlan
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, University of Galway, Ireland
| | - Simone Coughlan
- SFI Centre for Research Training in Genomics Data Science, University of Galway, Ireland
| | - Stefanus Bernard
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, University of Galway, Ireland
- SFI Centre for Research Training in Genomics Data Science, University of Galway, Ireland
| | - Corrado Santocanale
- Centre for Chromosome Biology, School of Biological and Chemical Sciences, University of Galway, Ireland
- SFI Centre for Research Training in Genomics Data Science, University of Galway, Ireland
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8
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Hoggard T, Chacin E, Hollatz AJ, Kurat CF, Fox CA. The budding yeast Fkh1 Forkhead associated (FHA) domain promoted a G1-chromatin state and the activity of chromosomal DNA replication origins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.16.580712. [PMID: 38405780 PMCID: PMC10889021 DOI: 10.1101/2024.02.16.580712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
In Saccharomyces cerevisiae, the forkhead (Fkh) transcription factor Fkh1 (forkhead homolog) enhances the activity of many DNA replication origins that act in early S-phase (early origins). Current models posit that Fkh1 acts directly to promote these origins' activity by binding to origin-adjacent Fkh1 binding sites (FKH sites). However, the post-DNA binding functions that Fkh1 uses to promote early origin activity are poorly understood. Fkh1 contains a conserved FHA (forkhead associated) domain, a protein-binding module with specificity for phosphothreonine (pT)-containing partner proteins. At a small subset of yeast origins, the Fkh1-FHA domain enhances the ORC (origin recognition complex)-origin binding step, the G1-phase event that initiates the origin cycle. However, the importance of the Fkh1-FHA domain to either chromosomal replication or ORC-origin interactions at genome scale is unclear. Here, S-phase SortSeq experiments were used to compare genome replication in proliferating FKH1 and fkh1-R80A mutant cells. The Fkh1-FHA domain promoted the activity of 100 origins that act in early to mid- S-phase, including the majority of centromere-associated origins, while simultaneously inhibiting 100 late origins. Thus, in the absence of a functional Fkh1-FHA domain, the temporal landscape of the yeast genome was flattened. Origins are associated with a positioned nucleosome array that frames a nucleosome depleted region (NDR) over the origin, and ORC-origin binding is necessary but not sufficient for this chromatin organization. To ask whether the Fkh1-FHA domain had an impact on this chromatin architecture at origins, ORC ChIPSeq data generated from proliferating cells and MNaseSeq data generated from G1-arrested and proliferating cell populations were assessed. Origin groups that were differentially regulated by the Fkh1-FHA domain were characterized by distinct effects of this domain on ORC-origin binding and G1-phase chromatin. Thus, the Fkh1-FHA domain controlled the distinct chromatin architecture at early origins in G1-phase and regulated origin activity in S-phase.
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Affiliation(s)
- Timothy Hoggard
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin, Madison
| | - Erika Chacin
- Biomedical Center Munich (BMC), Division of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, Martinsried, Germany
| | - Allison J. Hollatz
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin, Madison
- Integrated Program in Biochemistry, University of Wisconsin, Madison
| | - Christoph F. Kurat
- Biomedical Center Munich (BMC), Division of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, Martinsried, Germany
| | - Catherine A. Fox
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin, Madison
- Integrated Program in Biochemistry, University of Wisconsin, Madison
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9
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Day M, Tetik B, Parlak M, Almeida-Hernández Y, Räschle M, Kaschani F, Siegert H, Marko A, Sanchez-Garcia E, Kaiser M, Barker IA, Pearl LH, Oliver AW, Boos D. TopBP1 utilises a bipartite GINS binding mode to support genome replication. Nat Commun 2024; 15:1797. [PMID: 38413589 PMCID: PMC10899662 DOI: 10.1038/s41467-024-45946-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 02/07/2024] [Indexed: 02/29/2024] Open
Abstract
Activation of the replicative Mcm2-7 helicase by loading GINS and Cdc45 is crucial for replication origin firing, and as such for faithful genetic inheritance. Our biochemical and structural studies demonstrate that the helicase activator GINS interacts with TopBP1 through two separate binding surfaces, the first involving a stretch of highly conserved amino acids in the TopBP1-GINI region, the second a surface on TopBP1-BRCT4. The two surfaces bind to opposite ends of the A domain of the GINS subunit Psf1. Mutation analysis reveals that either surface is individually able to support TopBP1-GINS interaction, albeit with reduced affinity. Consistently, either surface is sufficient for replication origin firing in Xenopus egg extracts and becomes essential in the absence of the other. The TopBP1-GINS interaction appears sterically incompatible with simultaneous binding of DNA polymerase epsilon (Polε) to GINS when bound to Mcm2-7-Cdc45, although TopBP1-BRCT4 and the Polε subunit PolE2 show only partial competitivity in binding to Psf1. Our TopBP1-GINS model improves the understanding of the recently characterised metazoan pre-loading complex. It further predicts the coordination of three molecular origin firing processes, DNA polymerase epsilon arrival, TopBP1 ejection and GINS integration into Mcm2-7-Cdc45.
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Affiliation(s)
- Matthew Day
- School of Biological and Behavioural Sciences, Blizard Institute, Queen Mary University of London, London, E1 2AT, UK.
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9RQ, UK.
| | - Bilal Tetik
- Molecular Genetics II, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
| | - Milena Parlak
- Molecular Genetics II, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
| | - Yasser Almeida-Hernández
- Computational Bioengineering, Fakultät Bio- und Chemieingenieurwesen, Technical University Dortmund, Emil-Figge Str. 66, 44227, Dortmund, Germany
- Computational Biochemistry, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
| | - Markus Räschle
- Molecular Genetics, Technical University Kaiserslautern, Paul-Ehrlich Straße 24, 67663, Kaiserslautern, Germany
| | - Farnusch Kaschani
- Analytics Core Facility Essen, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
- Chemical Biology, Center of Medical Biotechnology, University Duisburg-Essen, Fakultät Biologie, Essen, Germany
| | - Heike Siegert
- Molecular Genetics II, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
| | - Anika Marko
- Molecular Genetics II, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
| | - Elsa Sanchez-Garcia
- Computational Bioengineering, Fakultät Bio- und Chemieingenieurwesen, Technical University Dortmund, Emil-Figge Str. 66, 44227, Dortmund, Germany
- Computational Biochemistry, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
| | - Markus Kaiser
- Analytics Core Facility Essen, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany
- Chemical Biology, Center of Medical Biotechnology, University Duisburg-Essen, Fakultät Biologie, Essen, Germany
| | - Isabel A Barker
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9RQ, UK
| | - Laurence H Pearl
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9RQ, UK.
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW1E 6BT, UK.
| | - Antony W Oliver
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9RQ, UK.
| | - Dominik Boos
- Molecular Genetics II, Center of Medical Biotechnology, University of Duisburg-Essen, Universitätsstraße 2-5, 45141, Essen, Germany.
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10
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Lee CSK, Weiβ M, Hamperl S. Where and when to start: Regulating DNA replication origin activity in eukaryotic genomes. Nucleus 2023; 14:2229642. [PMID: 37469113 PMCID: PMC10361152 DOI: 10.1080/19491034.2023.2229642] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/20/2023] [Accepted: 06/21/2023] [Indexed: 07/21/2023] Open
Abstract
In eukaryotic genomes, hundreds to thousands of potential start sites of DNA replication named origins are dispersed across each of the linear chromosomes. During S-phase, only a subset of origins is selected in a stochastic manner to assemble bidirectional replication forks and initiate DNA synthesis. Despite substantial progress in our understanding of this complex process, a comprehensive 'identity code' that defines origins based on specific nucleotide sequences, DNA structural features, the local chromatin environment, or 3D genome architecture is still missing. In this article, we review the genetic and epigenetic features of replication origins in yeast and metazoan chromosomes and highlight recent insights into how this flexibility in origin usage contributes to nuclear organization, cell growth, differentiation, and genome stability.
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Affiliation(s)
- Clare S K Lee
- Chromosome Dynamics and Genome Stability, Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Matthias Weiβ
- Chromosome Dynamics and Genome Stability, Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Stephan Hamperl
- Chromosome Dynamics and Genome Stability, Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
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11
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Reinapae A, Ilves I, Jürgens H, Värv S, Kristjuhan K, Kristjuhan A. Interactions between Fkh1 monomers stabilize its binding to DNA replication origins. J Biol Chem 2023; 299:105026. [PMID: 37423303 PMCID: PMC10403728 DOI: 10.1016/j.jbc.2023.105026] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 06/28/2023] [Accepted: 07/01/2023] [Indexed: 07/11/2023] Open
Abstract
Eukaryotic DNA replication is initiated from multiple genomic origins, which can be broadly categorized as firing early or late in the S phase. Several factors can influence the temporal usage of origins to determine the timing of their firing. In budding yeast, the Forkhead family proteins Fkh1 and Fkh2 bind to a subset of replication origins and activate them at the beginning of the S phase. In these origins, the Fkh1/2 binding sites are arranged in a strict configuration, suggesting that Forkhead factors must bind the origins in a specific manner. To explore these binding mechanisms in more detail, we mapped the domains of Fkh1 that were required for its role in DNA replication regulation. We found that a short region of Fkh1 near its DNA binding domain was essential for the protein to bind and activate replication origins. Analysis of purified Fkh1 proteins revealed that this region mediates dimerization of Fkh1, suggesting that intramolecular contacts of Fkh1 are required for efficient binding and regulation of DNA replication origins. We also show that the Sld3-Sld7-Cdc45 complex is recruited to Forkhead-regulated origins already in the G1 phase and that Fkh1 is constantly required to keep these factors bound on origins before the onset of the S phase. Together, our results suggest that dimerization-mediated stabilization of DNA binding by Fkh1 is crucial for its ability to activate DNA replication origins.
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Affiliation(s)
- Allan Reinapae
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Ivar Ilves
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Henel Jürgens
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Signe Värv
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Kersti Kristjuhan
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Arnold Kristjuhan
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia.
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12
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Arbona JM, Kabalane H, Barbier J, Goldar A, Hyrien O, Audit B. Neural network and kinetic modelling of human genome replication reveal replication origin locations and strengths. PLoS Comput Biol 2023; 19:e1011138. [PMID: 37253070 PMCID: PMC10256156 DOI: 10.1371/journal.pcbi.1011138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 06/09/2023] [Accepted: 04/30/2023] [Indexed: 06/01/2023] Open
Abstract
In human and other metazoans, the determinants of replication origin location and strength are still elusive. Origins are licensed in G1 phase and fired in S phase of the cell cycle, respectively. It is debated which of these two temporally separate steps determines origin efficiency. Experiments can independently profile mean replication timing (MRT) and replication fork directionality (RFD) genome-wide. Such profiles contain information on multiple origins' properties and on fork speed. Due to possible origin inactivation by passive replication, however, observed and intrinsic origin efficiencies can markedly differ. Thus, there is a need for methods to infer intrinsic from observed origin efficiency, which is context-dependent. Here, we show that MRT and RFD data are highly consistent with each other but contain information at different spatial scales. Using neural networks, we infer an origin licensing landscape that, when inserted in an appropriate simulation framework, jointly predicts MRT and RFD data with unprecedented precision and underlies the importance of dispersive origin firing. We furthermore uncover an analytical formula that predicts intrinsic from observed origin efficiency combined with MRT data. Comparison of inferred intrinsic origin efficiencies with experimental profiles of licensed origins (ORC, MCM) and actual initiation events (Bubble-seq, SNS-seq, OK-seq, ORM) show that intrinsic origin efficiency is not solely determined by licensing efficiency. Thus, human replication origin efficiency is set at both the origin licensing and firing steps.
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Affiliation(s)
- Jean-Michel Arbona
- Laboratoire de Biologie et Modélisation de la Cellule, ENS de Lyon, Lyon, France
| | - Hadi Kabalane
- ENS de Lyon, CNRS, Laboratoire de Physique, Lyon, France
| | - Jeremy Barbier
- ENS de Lyon, CNRS, Laboratoire de Physique, Lyon, France
| | - Arach Goldar
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Olivier Hyrien
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Benjamin Audit
- ENS de Lyon, CNRS, Laboratoire de Physique, Lyon, France
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13
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Hinshaw SM, Quan Y, Cai J, Zhou AL, Zhou H. Multi-site phosphorylation of yeast Mif2/CENP-C promotes inner kinetochore assembly. Curr Biol 2023; 33:688-696.e6. [PMID: 36736323 PMCID: PMC9992315 DOI: 10.1016/j.cub.2023.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/28/2022] [Accepted: 01/09/2023] [Indexed: 02/05/2023]
Abstract
Kinetochores control eukaryotic chromosome segregation by connecting chromosomal centromeres to spindle microtubules. Duplication of centromeric DNA necessitates kinetochore disassembly and subsequent reassembly on nascent sisters. To search for a regulatory mechanism that controls the earliest steps of this process, we studied Mif2/CENP-C, an essential basal component of the kinetochore. We found that phosphorylation of a central region of Mif2 (Mif2-PEST) enhances inner kinetochore assembly. Eliminating Mif2-PEST phosphorylation sites progressively impairs cellular fitness. The most severe Mif2-PEST mutations are lethal in cells lacking otherwise non-essential inner kinetochore factors. These data show that multi-site phosphorylation of Mif2/CENP-C controls inner kinetochore assembly.
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Affiliation(s)
- Stephen M Hinshaw
- Stanford Cancer Institute, Stanford School of Medicine, 1291 Welch Road, Stanford, CA 94305, USA.
| | - Yun Quan
- Department of Cellular and Molecular Medicine, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92039, USA
| | - Jiaxi Cai
- Department of Cellular and Molecular Medicine, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92039, USA
| | - Ann L Zhou
- Department of Cellular and Molecular Medicine, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92039, USA
| | - Huilin Zhou
- Department of Cellular and Molecular Medicine, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92039, USA.
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14
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Choudhary K, Kupiec M. The cohesin complex of yeasts: sister chromatid cohesion and beyond. FEMS Microbiol Rev 2023; 47:6825453. [PMID: 36370456 DOI: 10.1093/femsre/fuac045] [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: 09/13/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022] Open
Abstract
Each time a cell divides, it needs to duplicate the genome and then separate the two copies. In eukaryotes, which usually have more than one linear chromosome, this entails tethering the two newly replicated DNA molecules, a phenomenon known as sister chromatid cohesion (SCC). Cohesion ensures proper chromosome segregation to separate poles during mitosis. SCC is achieved by the presence of the cohesin complex. Besides its canonical function, cohesin is essential for chromosome organization and DNA damage repair. Surprisingly, yeast cohesin is loaded in G1 before DNA replication starts but only acquires its binding activity during DNA replication. Work in microorganisms, such as Saccharomyces cerevisiae and Schizosaccharomyces pombe has greatly contributed to the understanding of cohesin composition and functions. In the last few years, much progress has been made in elucidating the role of cohesin in chromosome organization and compaction. Here, we discuss the different functions of cohesin to ensure faithful chromosome segregation and genome stability during the mitotic cell division in yeast. We describe what is known about its composition and how DNA replication is coupled with SCC establishment. We also discuss current models for the role of cohesin in chromatin loop extrusion and delineate unanswered questions about the activity of this important, conserved complex.
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Affiliation(s)
- Karan Choudhary
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Martin Kupiec
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
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15
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Dbf4 Zn-Finger Motif Is Specifically Required for Stimulation of Ctf19-Activated Origins in Saccharomyces cerevisiae. Genes (Basel) 2022; 13:genes13122202. [PMID: 36553469 PMCID: PMC9778208 DOI: 10.3390/genes13122202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 11/11/2022] [Accepted: 11/17/2022] [Indexed: 11/25/2022] Open
Abstract
Eukaryotic genomes are replicated in spatiotemporal patterns that are stereotypical for individual genomes and developmental profiles. In the model system Saccharomyces cerevisiae, two primary mechanisms determine the preferential activation of replication origins during early S phase, thereby largely defining the consequent replication profiles of these cells. Both mechanisms are thought to act through specific recruitment of a rate-limiting initiation factor, Dbf4-dependent kinase (DDK), to a subset of licensed replication origins. Fkh1/2 is responsible for stimulation of most early-firing origins, except for centromere (CEN)-proximal origins that recruit DDK via the kinetochore protein Ctf19, which is required for their early firing. The C-terminus of Dbf4 has been implicated in its recruitment to origins via both the Fkh1/2 and Ctf19 mechanisms. Here, we show that the Zn-finger motif within the C-terminus is specifically required for Dbf4 recruitment to CENs to stimulate CEN-proximal/Ctf19-dependent origins, whereas stimulation of origins via the Fkh1/2 pathway remains largely intact. These findings re-open the question of exactly how Fkh1/2 and DDK act together to stimulate replication origin initiation.
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16
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Reusswig KU, Bittmann J, Peritore M, Courtes M, Pardo B, Wierer M, Mann M, Pfander B. Unscheduled DNA replication in G1 causes genome instability and damage signatures indicative of replication collisions. Nat Commun 2022; 13:7014. [PMID: 36400763 PMCID: PMC9674678 DOI: 10.1038/s41467-022-34379-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 10/24/2022] [Indexed: 11/19/2022] Open
Abstract
DNA replicates once per cell cycle. Interfering with the regulation of DNA replication initiation generates genome instability through over-replication and has been linked to early stages of cancer development. Here, we engineer genetic systems in budding yeast to induce unscheduled replication in a G1-like cell cycle state. Unscheduled G1 replication initiates at canonical S-phase origins. We quantifiy the composition of replisomes in G1- and S-phase and identified firing factors, polymerase α, and histone supply as factors that limit replication outside S-phase. G1 replication per se does not trigger cellular checkpoints. Subsequent replication during S-phase, however, results in over-replication and leads to chromosome breaks and chromosome-wide, strand-biased occurrence of RPA-bound single-stranded DNA, indicating head-to-tail replication collisions as a key mechanism generating genome instability upon G1 replication. Low-level, sporadic induction of G1 replication induces an identical response, indicating findings from synthetic systems are applicable to naturally occurring scenarios of unscheduled replication initiation.
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Affiliation(s)
- Karl-Uwe Reusswig
- grid.418615.f0000 0004 0491 845XDNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany ,grid.38142.3c000000041936754XPresent Address: Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115 USA ,grid.65499.370000 0001 2106 9910Present Address: Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215 USA
| | - Julia Bittmann
- grid.418615.f0000 0004 0491 845XDNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Martina Peritore
- grid.418615.f0000 0004 0491 845XDNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany ,grid.7551.60000 0000 8983 7915Present Address: Genome Maintenance Mechanisms in Health and Disease, Institute of Aerospace Medicine, German Aerospace Center (DLR), 51147 Cologne, Germany
| | - Mathilde Courtes
- grid.433120.7Institut de Génétique Humaine (IGH), Université de Montpellier – Centre National de la Recherche Scientifique, 34396 Montpellier, France
| | - Benjamin Pardo
- grid.433120.7Institut de Génétique Humaine (IGH), Université de Montpellier – Centre National de la Recherche Scientifique, 34396 Montpellier, France
| | - Michael Wierer
- grid.418615.f0000 0004 0491 845XProteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany ,grid.5254.60000 0001 0674 042XPresent Address: Proteomics Research Infrastructure, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Matthias Mann
- grid.418615.f0000 0004 0491 845XProteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Boris Pfander
- grid.418615.f0000 0004 0491 845XDNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany ,grid.7551.60000 0000 8983 7915Present Address: Genome Maintenance Mechanisms in Health and Disease, Institute of Aerospace Medicine, German Aerospace Center (DLR), 51147 Cologne, Germany ,grid.6190.e0000 0000 8580 3777Present Address: Genome Maintenance Mechanisms in Health and Disease, Institute of Genome Stability in Ageing and Disease, CECAD Research Center, University of Cologne, 50931 Cologne, Germany
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17
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Rhind N. DNA replication timing: Biochemical mechanisms and biological significance. Bioessays 2022; 44:e2200097. [PMID: 36125226 PMCID: PMC9783711 DOI: 10.1002/bies.202200097] [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: 05/16/2022] [Revised: 08/31/2022] [Accepted: 09/02/2022] [Indexed: 12/27/2022]
Abstract
The regulation of DNA replication is a fascinating biological problem both from a mechanistic angle-How is replication timing regulated?-and from an evolutionary one-Why is replication timing regulated? Recent work has provided significant insight into the first question. Detailed biochemical understanding of the mechanism and regulation of replication initiation has made possible robust hypotheses for how replication timing is regulated. Moreover, technical progress, including high-throughput, single-molecule mapping of replication initiation and single-cell assays of replication timing, has allowed for direct testing of these hypotheses in mammalian cells. This work has consolidated the conclusion that differential replication timing is a consequence of the varying probability of replication origin initiation. The second question is more difficult to directly address experimentally. Nonetheless, plausible hypotheses can be made and one-that replication timing contributes to the regulation of chromatin structure-has received new experimental support.
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Affiliation(s)
- Nicholas Rhind
- Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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18
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Santos MM, Johnson MC, Fiedler L, Zegerman P. Global early replication disrupts gene expression and chromatin conformation in a single cell cycle. Genome Biol 2022; 23:217. [PMID: 36253803 PMCID: PMC9575230 DOI: 10.1186/s13059-022-02788-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 10/10/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND The early embryonic divisions of many organisms, including fish, flies, and frogs, are characterized by a very rapid S-phase caused by high rates of replication initiation. In somatic cells, S-phase is much longer due to both a reduction in the total number of initiation events and the imposition of a temporal order of origin activation. The physiological importance of changes in the rate and timing of replication initiation in S-phase remains unclear. RESULTS Here we assess the importance of the temporal control of replication initiation using a conditional system in budding yeast to drive the early replication of the majority of origins in a single cell cycle. We show that global early replication disrupts the expression of over a quarter of all genes. By deleting individual origins, we show that delaying replication is sufficient to restore normal gene expression, directly implicating origin firing control in this regulation. Global early replication disrupts nucleosome positioning and transcription factor binding during S-phase, suggesting that the rate of S-phase is important to regulate the chromatin landscape. CONCLUSIONS Together, these data provide new insight into the role of the temporal control of origin firing during S-phase for coordinating replication, gene expression, and chromatin establishment as occurs in the early embryo.
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Affiliation(s)
- Miguel M Santos
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Mark C Johnson
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Lukáš Fiedler
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Philip Zegerman
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK.
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
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19
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JENKINSON F, ZEGERMAN P. Roles of phosphatases in eukaryotic DNA replication initiation control. DNA Repair (Amst) 2022; 118:103384. [DOI: 10.1016/j.dnarep.2022.103384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/28/2022] [Accepted: 07/30/2022] [Indexed: 11/03/2022]
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20
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Lazar-Stefanita L, Luo J, Montagne R, Thierry A, Sun X, Mercy G, Mozziconacci J, Koszul R, Boeke JD. Karyotype engineering reveals spatio-temporal control of replication firing and gene contacts. CELL GENOMICS 2022; 2:None. [PMID: 35983101 PMCID: PMC9365758 DOI: 10.1016/j.xgen.2022.100163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 03/30/2022] [Accepted: 07/06/2022] [Indexed: 10/27/2022]
Abstract
Eukaryotic genomes vary in terms of size, chromosome number, and genetic complexity. Their temporal organization is complex, reflecting coordination between DNA folding and function. Here, we used fused karyotypes of budding yeast to characterize the effects of chromosome length on nuclear architecture. We found that size-matched megachromosomes expand to occupy a larger fraction of the enlarged nucleus. Hi-C maps reveal changes in the three-dimensional structure corresponding to inactivated centromeres and telomeres. De-clustering of inactive centromeres results in their loss of early replication, highlighting a functional correlation between genome organization and replication timing. Repositioning of former telomere-proximal regions on chromosome arms exposed a subset of contacts between flocculin genes. Chromatin reorganization of megachromosomes during cell division remained unperturbed, and it revealed that centromere-rDNA contacts in anaphase, extending over 0.3 Mb on wild-type chromosome, cannot exceed ∼1.7 Mb. Our results highlight the relevance of engineered karyotypes to unveiling relationships between genome organization and function.
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21
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Zaffar E, Ferreira P, Sanchez-Pulido L, Boos D. The Role of MTBP as a Replication Origin Firing Factor. BIOLOGY 2022; 11:biology11060827. [PMID: 35741348 PMCID: PMC9219753 DOI: 10.3390/biology11060827] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/20/2022] [Accepted: 05/22/2022] [Indexed: 12/12/2022]
Abstract
The initiation step of replication at replication origins determines when and where in the genome replication machines, replisomes, are generated. Tight control of replication initiation helps facilitate the two main tasks of genome replication, to duplicate the genome accurately and exactly once each cell division cycle. The regulation of replication initiation must ensure that initiation occurs during the S phase specifically, that no origin fires more than once per cell cycle, that enough origins fire to avoid non-replicated gaps, and that the right origins fire at the right time but only in favorable circumstances. Despite its importance for genetic homeostasis only the main molecular processes of eukaryotic replication initiation and its cellular regulation are understood. The MTBP protein (Mdm2-binding protein) is so far the last core replication initiation factor identified in metazoan cells. MTBP is the orthologue of yeast Sld7. It is essential for origin firing, the maturation of pre-replicative complexes (pre-RCs) into replisomes, and is emerging as a regulation focus targeted by kinases and by regulated degradation. We present recent insight into the structure and cellular function of the MTBP protein in light of recent structural and biochemical studies revealing critical molecular details of the eukaryotic origin firing reaction. How the roles of MTBP in replication and other cellular processes are mutually connected and are related to MTBP's contribution to tumorigenesis remains largely unclear.
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Affiliation(s)
- Eman Zaffar
- Molecular Genetics II, Centre for Medical Biotechnology, University of Duisburg-Essen, 45141 Essen, Germany; (E.Z.); (P.F.)
| | - Pedro Ferreira
- Molecular Genetics II, Centre for Medical Biotechnology, University of Duisburg-Essen, 45141 Essen, Germany; (E.Z.); (P.F.)
| | - Luis Sanchez-Pulido
- Medical Research Council Human Genetics Unit, IGC, University of Edinburgh, Edinburgh EH9 3JR, UK;
| | - Dominik Boos
- Molecular Genetics II, Centre for Medical Biotechnology, University of Duisburg-Essen, 45141 Essen, Germany; (E.Z.); (P.F.)
- Correspondence: ; Tel.: +49-201-183-4132
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22
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Joseph CR, Dusi S, Giannattasio M, Branzei D. Rad51-mediated replication of damaged templates relies on monoSUMOylated DDK kinase. Nat Commun 2022; 13:2480. [PMID: 35513396 PMCID: PMC9072374 DOI: 10.1038/s41467-022-30215-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 04/21/2022] [Indexed: 12/24/2022] Open
Abstract
DNA damage tolerance (DDT), activated by replication stress during genome replication, is mediated by translesion synthesis and homologous recombination (HR). Here we uncover that DDK kinase, essential for replication initiation, is critical for replication-associated recombination-mediated DDT. DDK relies on its multi-monoSUMOylation to facilitate HR-mediated DDT and optimal retention of Rad51 recombinase at replication damage sites. Impairment of DDK kinase activity, reduced monoSUMOylation and mutations in the putative SUMO Interacting Motifs (SIMs) of Rad51 impair replication-associated recombination and cause fork uncoupling with accumulation of large single-stranded DNA regions at fork branching points. Notably, genetic activation of salvage recombination rescues the uncoupled fork phenotype but not the recombination-dependent gap-filling defect of DDK mutants, revealing that the salvage recombination pathway operates preferentially proximal to fork junctions at stalled replication forks. Overall, we uncover that monoSUMOylated DDK acts with Rad51 in an axis that prevents replication fork uncoupling and mediates recombination-dependent gap-filling.
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Affiliation(s)
- Chinnu Rose Joseph
- IFOM, Istituto Fondazione di Oncologia Molecolare, Via Adamello 16, 20139, Milan, Italy
| | - Sabrina Dusi
- IFOM, Istituto Fondazione di Oncologia Molecolare, Via Adamello 16, 20139, Milan, Italy
| | - Michele Giannattasio
- IFOM, Istituto Fondazione di Oncologia Molecolare, Via Adamello 16, 20139, Milan, Italy
- Università degli Studi di Milano, Dipartimento di Oncologia ed Emato-Oncologia, Via S. Sofia 9/1, 20122, Milano, Italy
| | - Dana Branzei
- IFOM, Istituto Fondazione di Oncologia Molecolare, Via Adamello 16, 20139, Milan, Italy.
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), 27100, Pavia, Italy.
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23
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The yeast Dbf4 Zn 2+ finger domain suppresses single-stranded DNA at replication forks initiated from a subset of origins. Curr Genet 2022; 68:253-265. [PMID: 35147742 PMCID: PMC8976809 DOI: 10.1007/s00294-022-01230-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 12/23/2021] [Accepted: 01/06/2022] [Indexed: 11/25/2022]
Abstract
Dbf4 is the cyclin-like subunit for the Dbf4-dependent protein kinase (DDK), required for activating the replicative helicase at DNA replication origin that fire during S phase. Dbf4 also functions as an adaptor, targeting the DDK to different groups of origins and substrates. Here we report a genome-wide analysis of origin firing in a budding yeast mutant, dbf4-zn, lacking the Zn2+ finger domain within the C-terminus of Dbf4. At one group of origins, which we call dromedaries, we observe an unanticipated DNA replication phenotype: accumulation of single-stranded DNA spanning ± 5kbp from the center of the origins. A similar accumulation of single-stranded DNA at origins occurs more globally in pri1-m4 mutants defective for the catalytic subunit of DNA primase and rad53 mutants defective for the S phase checkpoint following DNA replication stress. We propose the Dbf4 Zn2+ finger suppresses single-stranded gaps at replication forks emanating from dromedary origins. Certain origins may impose an elevated requirement for the DDK to fully initiate DNA synthesis following origin activation. Alternatively, dbf4-zn may be defective for stabilizing/restarting replication forks emanating from dromedary origins during replication stress.
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24
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Rhind N. f = m* a: A Framework for Investigating the Regulation of Replication Timing. Genes (Basel) 2022; 13:249. [PMID: 35205293 PMCID: PMC8872135 DOI: 10.3390/genes13020249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 01/21/2022] [Accepted: 01/24/2022] [Indexed: 12/04/2022] Open
Abstract
Stochastic models of replication timing posit that origin firing timing is regulated by origin firing probability, with early-firing origins having a high probability of firing and late-firing origins having a lower probability. However, they offer no insight into why one origin should have a higher firing probability than another. Here, a simple framework is suggested for how to approach the question by noting that the firing probability (f) must be the product of the stoichiometry of the MCM replicative helicase loaded at the origin (m) and the probability with which that MCM is activated (a). This framework emphasizes that mechanistic understanding of replication timing must focus on MCM loading and activation and can be simplified to the equation f = m*a.
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Affiliation(s)
- Nicholas Rhind
- Biochemistry and Molecular Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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25
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Mehta G, Sanyal K, Abhishek S, Rajakumara E, Ghosh SK. Minichromosome maintenance proteins in eukaryotic chromosome segregation. Bioessays 2021; 44:e2100218. [PMID: 34841543 DOI: 10.1002/bies.202100218] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/05/2021] [Accepted: 11/08/2021] [Indexed: 01/02/2023]
Abstract
Minichromosome maintenance (Mcm) proteins are well-known for their functions in DNA replication. However, their roles in chromosome segregation are yet to be reviewed in detail. Following the discovery in 1984, a group of Mcm proteins, known as the ARS-nonspecific group consisting of Mcm13, Mcm16-19, and Mcm21-22, were characterized as bonafide kinetochore proteins and were shown to play significant roles in the kinetochore assembly and high-fidelity chromosome segregation. This review focuses on the structure, function, and evolution of this group of Mcm proteins. Our in silico analysis of the physical interactors of these proteins reveals that they share non-overlapping functions despite being copurified in biochemically stable complexes. We have discussed the contrasting results reported in the literature and experimental strategies to address them. Taken together, this review focuses on the structure-function of the ARS-nonspecific Mcm proteins and their evolutionary flexibility to maintain genome stability in various organisms.
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Affiliation(s)
- Gunjan Mehta
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana, India
| | - Kaustuv Sanyal
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Bangalore, India
| | - Suman Abhishek
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana, India
| | - Eerappa Rajakumara
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana, India
| | - Santanu K Ghosh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
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26
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Mishra PK, Wood H, Stanton J, Au WC, Eisenstatt JR, Boeckmann L, Sclafani RA, Weinreich M, Bloom KS, Thorpe PH, Basrai MA. Cdc7-mediated phosphorylation of Cse4 regulates high-fidelity chromosome segregation in budding yeast. Mol Biol Cell 2021; 32:ar15. [PMID: 34432494 PMCID: PMC8693968 DOI: 10.1091/mbc.e21-06-0323] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/11/2021] [Accepted: 08/18/2021] [Indexed: 12/21/2022] Open
Abstract
Faithful chromosome segregation maintains chromosomal stability as errors in this process contribute to chromosomal instability (CIN), which has been observed in many diseases including cancer. Epigenetic regulation of kinetochore proteins such as Cse4 (CENP-A in humans) plays a critical role in high-fidelity chromosome segregation. Here we show that Cse4 is a substrate of evolutionarily conserved Cdc7 kinase, and that Cdc7-mediated phosphorylation of Cse4 prevents CIN. We determined that Cdc7 phosphorylates Cse4 in vitro and interacts with Cse4 in vivo in a cell cycle-dependent manner. Cdc7 is required for kinetochore integrity as reduced levels of CEN-associated Cse4, a faster exchange of Cse4 at the metaphase kinetochores, and defects in chromosome segregation, are observed in a cdc7-7 strain. Phosphorylation of Cse4 by Cdc7 is important for cell survival as constitutive association of a kinase-dead variant of Cdc7 (cdc7-kd) with Cse4 at the kinetochore leads to growth defects. Moreover, phospho-deficient mutations of Cse4 for consensus Cdc7 target sites contribute to CIN phenotype. In summary, our results have defined a role for Cdc7-mediated phosphorylation of Cse4 in faithful chromosome segregation.
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Affiliation(s)
- Prashant K. Mishra
- Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Henry Wood
- Queen Mary University of London, London E1 4NS, UK
| | - John Stanton
- University of North Carolina, Chapel Hill, NC 27599
| | - Wei-Chun Au
- Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Jessica R. Eisenstatt
- Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Lars Boeckmann
- Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | | | | | | | | | - Munira A. Basrai
- Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
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27
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Volpi I, Gillespie PJ, Chadha GS, Blow JJ. The role of DDK and Treslin-MTBP in coordinating replication licensing and pre-initiation complex formation. Open Biol 2021; 11:210121. [PMID: 34699733 PMCID: PMC8548084 DOI: 10.1098/rsob.210121] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 09/21/2021] [Indexed: 01/04/2023] Open
Abstract
Treslin/Ticrr is required for the initiation of DNA replication and binds to MTBP (Mdm2 Binding Protein). Here, we show that in Xenopus egg extract, MTBP forms an elongated tetramer with Treslin containing two molecules of each protein. Immunodepletion and add-back experiments show that Treslin-MTBP is rate limiting for replication initiation. It is recruited onto chromatin before S phase starts and recruitment continues during S phase. We show that DDK activity both increases and strengthens the interaction of Treslin-MTBP with licensed chromatin. We also show that DDK activity cooperates with CDK activity to drive the interaction of Treslin-MTBP with TopBP1 which is a regulated crucial step in pre-initiation complex formation. These results suggest how DDK works together with CDKs to regulate Treslin-MTBP and plays a crucial in selecting which origins will undergo initiation.
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Affiliation(s)
- Ilaria Volpi
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Peter J. Gillespie
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Gaganmeet Singh Chadha
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - J. Julian Blow
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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28
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Hsu CL, Lo YC, Kao CF. H3K4 Methylation in Aging and Metabolism. EPIGENOMES 2021; 5:14. [PMID: 34968301 PMCID: PMC8594702 DOI: 10.3390/epigenomes5020014] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/02/2021] [Accepted: 06/15/2021] [Indexed: 02/03/2023] Open
Abstract
During the process of aging, extensive epigenetic alterations are made in response to both exogenous and endogenous stimuli. Here, we summarize the current state of knowledge regarding one such alteration, H3K4 methylation (H3K4me), as it relates to aging in different species. We especially highlight emerging evidence that links this modification with metabolic pathways, which may provide a mechanistic link to explain its role in aging. H3K4me is a widely recognized marker of active transcription, and it appears to play an evolutionarily conserved role in determining organism longevity, though its influence is context specific and requires further clarification. Interestingly, the modulation of H3K4me dynamics may occur as a result of nutritional status, such as methionine restriction. Methionine status appears to influence H3K4me via changes in the level of S-adenosyl methionine (SAM, the universal methyl donor) or the regulation of H3K4-modifying enzyme activities. Since methionine restriction is widely known to extend lifespan, the mechanistic link between methionine metabolic flux, the sensing of methionine concentrations and H3K4me status may provide a cogent explanation for several seemingly disparate observations in aging organisms, including age-dependent H3K4me dynamics, gene expression changes, and physiological aberrations. These connections are not yet entirely understood, especially at a molecular level, and will require further elucidation. To conclude, we discuss some potential H3K4me-mediated molecular mechanisms that may link metabolic status to the aging process.
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Affiliation(s)
- Chia-Ling Hsu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan;
| | - Yi-Chen Lo
- Graduate Institute of Food Science and Technology, National Taiwan University, Taipei 10617, Taiwan;
| | - Cheng-Fu Kao
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan;
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29
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Cell-cycle phospho-regulation of the kinetochore. Curr Genet 2021; 67:177-193. [PMID: 33221975 DOI: 10.1007/s00294-020-01127-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 02/07/2023]
Abstract
The kinetochore is a mega-dalton protein assembly that forms within centromeric regions of chromosomes and directs their segregation during cell division. Here we review cell cycle-mediated phosphorylation events at the kinetochore, with a focus on the budding yeast Saccharomyces cerevisiae and the insight gained from forced associations of kinases and phosphatases. The point centromeres found in the budding yeast S. cerevisiae are one of the simplest such structures found in eukaryotes. The S. cerevisiae kinetochore comprises a single nucleosome, containing a centromere-specific H3 variant Cse4CENP-A, bound to a set of kinetochore proteins that connect to a single microtubule. Despite the simplicity of the budding yeast kinetochore, the proteins are mostly homologous with their mammalian counterparts. In some cases, human proteins can complement their yeast orthologs. Like its mammalian equivalent, the regulation of the budding yeast kinetochore is complex: integrating signals from the cell cycle, checkpoints, error correction, and stress pathways. The regulatory signals from these diverse pathways are integrated at the kinetochore by post-translational modifications, notably phosphorylation and dephosphorylation, to control chromosome segregation. Here we highlight the complex interplay between the activity of the different cell-cycle kinases and phosphatases at the kinetochore, emphasizing how much more we have to understand this essential structure.
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30
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Sreekumar L, Kumari K, Guin K, Bakshi A, Varshney N, Thimmappa BC, Narlikar L, Padinhateeri R, Siddharthan R, Sanyal K. Orc4 spatiotemporally stabilizes centromeric chromatin. Genome Res 2021; 31:607-621. [PMID: 33514624 PMCID: PMC8015856 DOI: 10.1101/gr.265900.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 01/27/2021] [Indexed: 11/24/2022]
Abstract
The establishment of centromeric chromatin and its propagation by the centromere-specific histone CENPA is mediated by epigenetic mechanisms in most eukaryotes. DNA replication origins, origin binding proteins, and replication timing of centromere DNA are important determinants of centromere function. The epigenetically regulated regional centromeres in the budding yeast Candida albicans have unique DNA sequences that replicate earliest in every chromosome and are clustered throughout the cell cycle. In this study, the genome-wide occupancy of the replication initiation protein Orc4 reveals its abundance at all centromeres in C. albicans Orc4 is associated with four different DNA sequence motifs, one of which coincides with tRNA genes (tDNA) that replicate early and cluster together in space. Hi-C combined with genome-wide replication timing analyses identify that early replicating Orc4-bound regions interact with themselves stronger than with late replicating Orc4-bound regions. We simulate a polymer model of chromosomes of C. albicans and propose that the early replicating and highly enriched Orc4-bound sites preferentially localize around the clustered kinetochores. We also observe that Orc4 is constitutively localized to centromeres, and both Orc4 and the helicase Mcm2 are essential for cell viability and CENPA stability in C. albicans Finally, we show that new molecules of CENPA are recruited to centromeres during late anaphase/telophase, which coincides with the stage at which the CENPA-specific chaperone Scm3 localizes to the kinetochore. We propose that the spatiotemporal localization of Orc4 within the nucleus, in collaboration with Mcm2 and Scm3, maintains centromeric chromatin stability and CENPA recruitment in C. albicans.
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Affiliation(s)
- Lakshmi Sreekumar
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Kiran Kumari
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
- IITB-Monash Research Academy, Mumbai 400076, India
- Department of Chemical Engineering, Monash University, Melbourne 3800, Australia
| | - Krishnendu Guin
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Asif Bakshi
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Neha Varshney
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Bhagya C Thimmappa
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Leelavati Narlikar
- Department of Chemical Engineering, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Ranjith Padinhateeri
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Rahul Siddharthan
- The Institute of Mathematical Sciences/HBNI, Taramani, Chennai 600113, India
| | - Kaustuv Sanyal
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
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31
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Dukaj L, Rhind N. The capacity of origins to load MCM establishes replication timing patterns. PLoS Genet 2021; 17:e1009467. [PMID: 33764973 PMCID: PMC8023499 DOI: 10.1371/journal.pgen.1009467] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 04/06/2021] [Accepted: 03/04/2021] [Indexed: 11/24/2022] Open
Abstract
Loading of the MCM replicative helicase at origins of replication is a highly regulated process that precedes DNA replication in all eukaryotes. The stoichiometry of MCM loaded at origins has been proposed to be a key determinant of when those origins initiate replication during S phase. Nevertheless, the genome-wide regulation of MCM loading stoichiometry and its direct effect on replication timing remain unclear. In order to investigate why some origins load more MCM than others, we perturbed MCM levels in budding yeast cells and, for the first time, directly measured MCM levels and replication timing in the same experiment. Reduction of MCM levels through degradation of Mcm4, one of the six obligate components of the MCM complex, slowed progression through S phase and increased sensitivity to replication stress. Reduction of MCM levels also led to differential loading at origins during G1, revealing origins that are sensitive to reductions in MCM and others that are not. Sensitive origins loaded less MCM under normal conditions and correlated with a weak ability to recruit the origin recognition complex (ORC). Moreover, reduction of MCM loading at specific origins of replication led to a delay in their replication during S phase. In contrast, overexpression of MCM had no effects on cell cycle progression, relative MCM levels at origins, or replication timing, suggesting that, under optimal growth conditions, cellular MCM levels are not limiting for MCM loading. Our results support a model in which the loading capacity of origins is the primary determinant of MCM stoichiometry in wild-type cells, but that stoichiometry is controlled by origins' ability to recruit ORC and compete for MCM when MCM becomes limiting.
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Affiliation(s)
- Livio Dukaj
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School Worcester, Massachusetts, United States of America
| | - Nicholas Rhind
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School Worcester, Massachusetts, United States of America
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32
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Singh P, Pesenti ME, Maffini S, Carmignani S, Hedtfeld M, Petrovic A, Srinivasamani A, Bange T, Musacchio A. BUB1 and CENP-U, Primed by CDK1, Are the Main PLK1 Kinetochore Receptors in Mitosis. Mol Cell 2021; 81:67-87.e9. [PMID: 33248027 PMCID: PMC7837267 DOI: 10.1016/j.molcel.2020.10.040] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 09/08/2020] [Accepted: 10/28/2020] [Indexed: 02/02/2023]
Abstract
Reflecting its pleiotropic functions, Polo-like kinase 1 (PLK1) localizes to various sub-cellular structures during mitosis. At kinetochores, PLK1 contributes to microtubule attachments and mitotic checkpoint signaling. Previous studies identified a wealth of potential PLK1 receptors at kinetochores, as well as requirements for various mitotic kinases, including BUB1, Aurora B, and PLK1 itself. Here, we combine ectopic localization, in vitro reconstitution, and kinetochore localization studies to demonstrate that most and likely all of the PLK1 is recruited through BUB1 in the outer kinetochore and centromeric protein U (CENP-U) in the inner kinetochore. BUB1 and CENP-U share a constellation of sequence motifs consisting of a putative PP2A-docking motif and two neighboring PLK1-docking sites, which, contingent on priming phosphorylation by cyclin-dependent kinase 1 and PLK1 itself, bind PLK1 and promote its dimerization. Our results rationalize previous observations and describe a unifying mechanism for recruitment of PLK1 to human kinetochores.
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Affiliation(s)
- Priyanka Singh
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Marion E Pesenti
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Stefano Maffini
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Sara Carmignani
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Marius Hedtfeld
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Arsen Petrovic
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Anupallavi Srinivasamani
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Tanja Bange
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany; Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Universitätsstrasse, 45141 Essen, Germany.
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33
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Cooke SL, Soares BL, Müller CA, Nieduszynski CA, Bastos de Oliveira FM, de Bruin RAM. Tos4 mediates gene expression homeostasis through interaction with HDAC complexes independently of H3K56 acetylation. J Biol Chem 2021; 296:100533. [PMID: 33713703 PMCID: PMC8054192 DOI: 10.1016/j.jbc.2021.100533] [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: 12/03/2020] [Revised: 03/03/2021] [Accepted: 03/09/2021] [Indexed: 11/25/2022] Open
Abstract
Saccharomyces cerevisiae exhibits gene expression homeostasis, which is defined as the buffering of transcription levels against changes in DNA copy number during the S phase of the cell cycle. It has been suggested that S. cerevisiae employs an active mechanism to maintain gene expression homeostasis through Rtt109-Asf1-dependent acetylation of histone H3 on lysine 56 (H3K56). Here, we show that gene expression homeostasis can be achieved independently of H3K56 acetylation by Tos4 (Target of Swi6-4). Using Nanostring technology, we establish that Tos4-dependent gene expression homeostasis depends on its forkhead-associated (FHA) domain, which is a phosphopeptide recognition domain required to bind histone deacetylases (HDACs). We demonstrate that the mechanism of Tos4-dependent gene expression homeostasis requires its interaction with the Rpd3L HDAC complex. However, this is independent of Rpd3's well-established roles in both histone deacetylation and controlling the DNA replication timing program, as established by deep sequencing of Fluorescence-Activated Cell Sorted (FACS) S and G2 phase populations. Overall, our data reveals that Tos4 mediates gene expression homeostasis through its FHA domain-dependent interaction with the Rpd3L complex, which is independent of H3K56ac.
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Affiliation(s)
- Sophie L Cooke
- MRC Laboratory Molecular Cell Biology, University College London, London, UK
| | - Barbara L Soares
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carolin A Müller
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Conrad A Nieduszynski
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK; Genome Damage and Stability Centre, University of Sussex, Brighton, UK
| | | | - Robertus A M de Bruin
- MRC Laboratory Molecular Cell Biology, University College London, London, UK; UCL Cancer Institute, University College London, London, UK.
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34
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Wear EE, Song J, Zynda GJ, Mickelson-Young L, LeBlanc C, Lee TJ, Deppong DO, Allen GC, Martienssen RA, Vaughn MW, Hanley-Bowdoin L, Thompson WF. Comparing DNA replication programs reveals large timing shifts at centromeres of endocycling cells in maize roots. PLoS Genet 2020; 16:e1008623. [PMID: 33052904 PMCID: PMC7588055 DOI: 10.1371/journal.pgen.1008623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 10/26/2020] [Accepted: 08/28/2020] [Indexed: 12/20/2022] Open
Abstract
Plant cells undergo two types of cell cycles–the mitotic cycle in which DNA replication is coupled to mitosis, and the endocycle in which DNA replication occurs in the absence of cell division. To investigate DNA replication programs in these two types of cell cycles, we pulse labeled intact root tips of maize (Zea mays) with 5-ethynyl-2’-deoxyuridine (EdU) and used flow sorting of nuclei to examine DNA replication timing (RT) during the transition from a mitotic cycle to an endocycle. Comparison of the sequence-based RT profiles showed that most regions of the maize genome replicate at the same time during S phase in mitotic and endocycling cells, despite the need to replicate twice as much DNA in the endocycle and the fact that endocycling is typically associated with cell differentiation. However, regions collectively corresponding to 2% of the genome displayed significant changes in timing between the two types of cell cycles. The majority of these regions are small with a median size of 135 kb, shift to a later RT in the endocycle, and are enriched for genes expressed in the root tip. We found larger regions that shifted RT in centromeres of seven of the ten maize chromosomes. These regions covered the majority of the previously defined functional centromere, which ranged between 1 and 2 Mb in size in the reference genome. They replicate mainly during mid S phase in mitotic cells but primarily in late S phase of the endocycle. In contrast, the immediately adjacent pericentromere sequences are primarily late replicating in both cell cycles. Analysis of CENH3 enrichment levels in 8C vs 2C nuclei suggested that there is only a partial replacement of CENH3 nucleosomes after endocycle replication is complete. The shift to later replication of centromeres and possible reduction in CENH3 enrichment after endocycle replication is consistent with a hypothesis that centromeres are inactivated when their function is no longer needed. In traditional cell division, or mitosis, a cell’s genetic material is duplicated and then split between two daughter cells. In contrast, in some specialized cell types, the DNA is duplicated a second time without an intervening division step, resulting in cells that carry twice as much DNA. This phenomenon, which is called the endocycle, is common during plant development. At each step, DNA replication follows an ordered program in which highly compacted DNA is unraveled and replicated in sections at different times during the synthesis (S) phase. In plants, it is unclear whether traditional and endocycle programs are the same, especially since endocycling cells are typically in the process of differentiation. Using root tips of maize, we found that in comparison to replication in the mitotic cell cycle, there is a small portion of the genome whose replication in the endocycle is shifted in time, usually to later in S phase. Some of these regions are scattered around the genome and mostly coincide with active genes. However, the most prominent shifts occur in centromeres. The shift to later replication in centromeres is noteworthy because they orchestrate the process of separating duplicated chromosomes into daughter cells, a function that is not needed in the endocycle.
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Affiliation(s)
- Emily E. Wear
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail:
| | - Jawon Song
- Texas Advanced Computing Center, University of Texas, Austin, Texas, United States of America
| | - Gregory J. Zynda
- Texas Advanced Computing Center, University of Texas, Austin, Texas, United States of America
| | - Leigh Mickelson-Young
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Chantal LeBlanc
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - Tae-Jin Lee
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - David O. Deppong
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - George C. Allen
- Department of Horticultural Science, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Robert A. Martienssen
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - Matthew W. Vaughn
- Texas Advanced Computing Center, University of Texas, Austin, Texas, United States of America
| | - Linda Hanley-Bowdoin
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - William F. Thompson
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, United States of America
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Meiotic CENP-C is a shepherd: bridging the space between the centromere and the kinetochore in time and space. Essays Biochem 2020; 64:251-261. [PMID: 32794572 DOI: 10.1042/ebc20190080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/15/2020] [Accepted: 07/20/2020] [Indexed: 01/10/2023]
Abstract
While many of the proteins involved in the mitotic centromere and kinetochore are conserved in meiosis, they often gain a novel function due to the unique needs of homolog segregation during meiosis I (MI). CENP-C is a critical component of the centromere for kinetochore assembly in mitosis. Recent work, however, has highlighted the unique features of meiotic CENP-C. Centromere establishment and stability require CENP-C loading at the centromere for CENP-A function. Pre-meiotic loading of proteins necessary for homolog recombination as well as cohesion also rely on CENP-C, as do the main scaffolding components of the kinetochore. Much of this work relies on new technologies that enable in vivo analysis of meiosis like never before. Here, we strive to highlight the unique role of this highly conserved centromere protein that loads on to centromeres prior to M-phase onset, but continues to perform critical functions through chromosome segregation. CENP-C is not merely a structural link between the centromere and the kinetochore, but also a functional one joining the processes of early prophase homolog synapsis to late metaphase kinetochore assembly and signaling.
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Guin K, Sreekumar L, Sanyal K. Implications of the Evolutionary Trajectory of Centromeres in the Fungal Kingdom. Annu Rev Microbiol 2020; 74:835-853. [PMID: 32706633 DOI: 10.1146/annurev-micro-011720-122512] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chromosome segregation during the cell cycle is an evolutionarily conserved, fundamental biological process. Dynamic interaction between spindle microtubules and the kinetochore complex that assembles on centromere DNA is required for faithful chromosome segregation. The first artificial minichromosome was constructed by cloning the centromere DNA of the budding yeast Saccharomyces cerevisiae. Since then, centromeres have been identified in >60 fungal species. The DNA sequence and organization of the sequence elements are highly diverse across these fungal centromeres. In this article, we provide a comprehensive view of the evolution of fungal centromeres. Studies of this process facilitated the identification of factors influencing centromere specification, maintenance, and propagation through many generations. Additionally, we discuss the unique features and plasticity of centromeric chromatin and the involvement of centromeres in karyotype evolution. Finally, we discuss the implications of recurrent loss of RNA interference (RNAi) and/or heterochromatin components on the trajectory of the evolution of fungal centromeres and propose the centromere structure of the last common ancestor of three major fungal phyla-Ascomycota, Basidiomycota, and Mucoromycota.
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Affiliation(s)
- Krishnendu Guin
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka 560064, India; , ,
| | - Lakshmi Sreekumar
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka 560064, India; , ,
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka 560064, India; , ,
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Chromatin and Nuclear Architecture: Shaping DNA Replication in 3D. Trends Genet 2020; 36:967-980. [PMID: 32713597 DOI: 10.1016/j.tig.2020.07.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/26/2020] [Accepted: 07/02/2020] [Indexed: 12/13/2022]
Abstract
In eukaryotes, DNA replication progresses through a finely orchestrated temporal and spatial program. The 3D genome structure and nuclear architecture have recently emerged as fundamental determinants of the replication program. Factors with established roles in replication have been recognized as genome organization regulators. Exploiting paradigms from yeasts and mammals, we discuss how DNA replication is regulated in time and space through DNA-associated trans-acting factors, diffusible limiting replication initiation factors, higher-order chromatin folding, dynamic origin localization, and specific nuclear microenvironments. We present an integrated model for the regulation of DNA replication in 3D and highlight the importance of accurate spatio-temporal regulation of DNA replication in physiology and disease.
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Sir2 mitigates an intrinsic imbalance in origin licensing efficiency between early- and late-replicating euchromatin. Proc Natl Acad Sci U S A 2020; 117:14314-14321. [PMID: 32513739 PMCID: PMC7322022 DOI: 10.1073/pnas.2004664117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A eukaryotic chromosome relies on the function of multiple spatially distributed DNA replication origins for its stable inheritance. The spatial location of an origin is determined by the chromosomal position of an MCM complex, the inactive form of the DNA replicative helicase that is assembled onto DNA in G1-phase (also known as origin licensing). While the biochemistry of origin licensing is understood, the mechanisms that promote an adequate spatial distribution of MCM complexes across chromosomes are not. We have elucidated a role for the Sir2 histone deacetylase in establishing the normal distribution of MCM complexes across Saccharomyces cerevisiae chromosomes. In the absence of Sir2, MCM complexes accumulated within both early-replicating euchromatin and telomeric heterochromatin, and replication activity within these regions was enhanced. Concomitantly, the duplication of several regions of late-replicating euchromatin were delayed. Thus, Sir2-mediated attenuation of origin licensing within both euchromatin and telomeric heterochromatin established the normal spatial distribution of origins across yeast chromosomes important for normal genome duplication.
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Structural Basis for the Activation and Target Site Specificity of CDC7 Kinase. Structure 2020; 28:954-962.e4. [PMID: 32521228 PMCID: PMC7416108 DOI: 10.1016/j.str.2020.05.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/11/2020] [Accepted: 05/19/2020] [Indexed: 12/13/2022]
Abstract
CDC7 is an essential Ser/Thr kinase that acts upon the replicative helicase throughout the S phase of the cell cycle and is activated by DBF4. Here, we present crystal structures of a highly active human CDC7-DBF4 construct. The structures reveal a zinc-finger domain at the end of the kinase insert 2 that pins the CDC7 activation loop to motif M of DBF4 and the C lobe of CDC7. These interactions lead to ordering of the substrate-binding platform and full opening of the kinase active site. In a co-crystal structure with a mimic of MCM2 Ser40 phosphorylation target, the invariant CDC7 residues Arg373 and Arg380 engage phospho-Ser41 at substrate P+1 position, explaining the selectivity of the S-phase kinase for Ser/Thr residues followed by a pre-phosphorylated or an acidic residue. Our results clarify the role of DBF4 in activation of CDC7 and elucidate the structural basis for recognition of its preferred substrates. DBF4 activates CDC7 kinase via a two-step mechanism Zinc-finger domain in CDC7 KI2 interacts with DBF4 motif M Invariant CDC7 residues Arg373 and Arg380 engage P+1 substrate site
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40
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Dbf4-Dependent Kinase (DDK)-Mediated Proteolysis of CENP-A Prevents Mislocalization of CENP-A in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2020; 10:2057-2068. [PMID: 32295767 PMCID: PMC7263675 DOI: 10.1534/g3.120.401131] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The evolutionarily conserved centromeric histone H3 variant (Cse4 in budding yeast, CENP-A in humans) is essential for faithful chromosome segregation. Mislocalization of CENP-A to non-centromeric chromatin contributes to chromosomal instability (CIN) in yeast, fly, and human cells and CENP-A is highly expressed and mislocalized in cancers. Defining mechanisms that prevent mislocalization of CENP-A is an area of active investigation. Ubiquitin-mediated proteolysis of overexpressed Cse4 (GALCSE4) by E3 ubiquitin ligases such as Psh1 prevents mislocalization of Cse4, and psh1 Δ strains display synthetic dosage lethality (SDL) with GALCSE4 We previously performed a genome-wide screen and identified five alleles of CDC7 and DBF4 that encode the Dbf4-dependent kinase (DDK) complex, which regulates DNA replication initiation, among the top twelve hits that displayed SDL with GALCSE4 We determined that cdc7 -7 strains exhibit defects in ubiquitin-mediated proteolysis of Cse4 and show mislocalization of Cse4 Mutation of MCM5 (mcm5 -bob1) bypasses the requirement of Cdc7 for replication initiation and rescues replication defects in a cdc7 -7 strain. We determined that mcm5 -bob1 does not rescue the SDL and defects in proteolysis of GALCSE4 in a cdc7 -7 strain, suggesting a DNA replication-independent role for Cdc7 in Cse4 proteolysis. The SDL phenotype, defects in ubiquitin-mediated proteolysis, and the mislocalization pattern of Cse4 in a cdc7 -7 psh1 Δ strain were similar to that of cdc7 -7 and psh1 Δ strains, suggesting that Cdc7 regulates Cse4 in a pathway that overlaps with Psh1 Our results define a DNA replication initiation-independent role of DDK as a regulator of Psh1-mediated proteolysis of Cse4 to prevent mislocalization of Cse4.
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DNA copy-number measurement of genome replication dynamics by high-throughput sequencing: the sort-seq, sync-seq and MFA-seq family. Nat Protoc 2020; 15:1255-1284. [PMID: 32051615 DOI: 10.1038/s41596-019-0287-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 12/16/2019] [Indexed: 12/20/2022]
Abstract
Genome replication follows a defined temporal programme that can change during cellular differentiation and disease onset. DNA replication results in an increase in DNA copy number that can be measured by high-throughput sequencing. Here we present a protocol to determine genome replication dynamics using DNA copy-number measurements. Cell populations can be obtained in three variants of the method. First, sort-seq reveals the average replication dynamics across S phase in an unperturbed cell population; FACS is used to isolate replicating and non-replicating subpopulations from asynchronous cells. Second, sync-seq measures absolute replication time at specific points during S phase using a synchronized cell population. Third, marker frequency analysis can be used to reveal the average replication dynamics using copy-number analysis in any proliferating asynchronous cell culture. These approaches have been used to reveal genome replication dynamics in prokaryotes, archaea and a wide range of eukaryotes, including yeasts and mammalian cells. We have found this approach straightforward to apply to other organisms and highlight example studies from across the three domains of life. Here we present a Saccharomyces cerevisiae version of the protocol that can be performed in 7-10 d. It requires basic molecular and cellular biology skills, as well as a basic understanding of Unix and R.
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Jin Y, Liang Z, Lou H. The Emerging Roles of Fox Family Transcription Factors in Chromosome Replication, Organization, and Genome Stability. Cells 2020; 9:cells9010258. [PMID: 31968679 PMCID: PMC7016735 DOI: 10.3390/cells9010258] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/13/2020] [Accepted: 01/14/2020] [Indexed: 12/13/2022] Open
Abstract
The forkhead box (Fox) transcription factors (TFs) are widespread from yeast to humans. Their mutations and dysregulation have been linked to a broad spectrum of malignant neoplasias. They are known as critical players in DNA repair, metabolism, cell cycle control, differentiation, and aging. Recent studies, especially those from the simple model eukaryotes, revealed unexpected contributions of Fox TFs in chromosome replication and organization. More importantly, besides functioning as a canonical TF in cell signaling cascades and gene expression, Fox TFs can directly participate in DNA replication and determine the global replication timing program in a transcription-independent mechanism. Yeast Fox TFs preferentially recruit the limiting replication factors to a subset of early origins on chromosome arms. Attributed to their dimerization capability and distinct DNA binding modes, Fkh1 and Fkh2 also promote the origin clustering and assemblage of replication elements (replication factories). They can mediate long-range intrachromosomal and interchromosomal interactions and thus regulate the four-dimensional chromosome organization. The novel aspects of Fox TFs reviewed here expand their roles in maintaining genome integrity and coordinating the multiple essential chromosome events. These will inevitably be translated to our knowledge and new treatment strategies of Fox TF-associated human diseases including cancer.
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Marchal C, Sima J, Gilbert DM. Control of DNA replication timing in the 3D genome. Nat Rev Mol Cell Biol 2019; 20:721-737. [PMID: 31477886 PMCID: PMC11567694 DOI: 10.1038/s41580-019-0162-y] [Citation(s) in RCA: 173] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2019] [Indexed: 12/27/2022]
Abstract
The 3D organization of mammalian chromatin was described more than 30 years ago by visualizing sites of DNA synthesis at different times during the S phase of the cell cycle. These early cytogenetic studies revealed structurally stable chromosome domains organized into subnuclear compartments. Active-gene-rich domains in the nuclear interior replicate early, whereas more condensed chromatin domains that are largely at the nuclear and nucleolar periphery replicate later. During the past decade, this spatiotemporal DNA replication programme has been mapped along the genome and found to correlate with epigenetic marks, transcriptional activity and features of 3D genome architecture such as chromosome compartments and topologically associated domains. But the causal relationship between these features and DNA replication timing and the regulatory mechanisms involved have remained an enigma. The recent identification of cis-acting elements regulating the replication time and 3D architecture of individual replication domains and of long non-coding RNAs that coordinate whole chromosome replication provide insights into such mechanisms.
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Affiliation(s)
- Claire Marchal
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Jiao Sima
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - David M Gilbert
- Department of Biological Science, Florida State University, Tallahassee, FL, USA.
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Lynch KL, Alvino GM, Kwan EX, Brewer BJ, Raghuraman MK. The effects of manipulating levels of replication initiation factors on origin firing efficiency in yeast. PLoS Genet 2019; 15:e1008430. [PMID: 31584938 PMCID: PMC6795477 DOI: 10.1371/journal.pgen.1008430] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 10/16/2019] [Accepted: 09/17/2019] [Indexed: 12/22/2022] Open
Abstract
Chromosome replication in Saccharomyces cerevisiae is initiated from ~300 origins that are regulated by DNA sequence and by the limited abundance of six trans-acting initiation proteins (Sld2, Sld3, Dpb11, Dbf4, Sld7 and Cdc45). We set out to determine how the levels of individual factors contribute to time of origin activation and/or origin efficiency using induced depletion of single factors and overexpression of sets of multiple factors. Depletion of Sld2 or Sld3 slows growth and S phase progression, decreases origin efficiency across the genome and impairs viability as a result of incomplete replication of the rDNA. We find that the most efficient early origins are relatively unaffected by depletion of either Sld2 or Sld3. However, Sld3 levels, and to a lesser extent Sld2 levels, are critical for firing of the less efficient early origins. Overexpression of Sld3 simultaneously with Sld2, Dpb11 and Dbf4 preserves the relative efficiency of origins. Only when Cdc45 and Sld7 are also overexpressed is origin efficiency equalized between early- and late-firing origins. Our data support a model in which Sld3 together with Cdc45 (and/or Sld7) is responsible for the differential efficiencies of origins across the yeast genome. Eukaryotic chromosome duplication begins at sites called origins of replication along the chromosomal DNA. A conserved property of eukaryotic origins is that they vary in efficiency—the proportion of cells in a population in which they “fire”—and in the average time of activation within S phase, but the molecular details underlying this variation are not well understood. Previous work has shown that limiting concentrations of a set of conserved replication initiation proteins referred to as “SSDDCS” (Sld2, Sld3, Dbf4, Dpb11, Cdc45, and Sld7) are rate limiting for origin activation in budding yeast and other eukaryotes; combined overexpression of these proteins increases and/or advances origin firing. However, it remained possible that different factors affect different aspects of origin activation (e.g., timing vs. efficiency). Here, by depleting individual factors or by overexpressing sets of factors in budding yeast, we demonstrate that it is levels of Sld3, Cdc45 and/or Sld7 levels are primarily responsible for modulating the differences in relative origin efficiency and timing. This work gives further insights into what shapes the landscape of genome duplication.
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Affiliation(s)
- Kelsey L. Lynch
- Molecular and Cellular Biology Program, University of Washington, Seattle, Washington, United States of America
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Gina M. Alvino
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Elizabeth X. Kwan
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Bonita J. Brewer
- Molecular and Cellular Biology Program, University of Washington, Seattle, Washington, United States of America
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - M. K. Raghuraman
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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45
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Chen CF, Pohl TJ, Chan A, Slocum JS, Zakian VA. Saccharomyces cerevisiae Centromere RNA Is Negatively Regulated by Cbf1 and Its Unscheduled Synthesis Impacts CenH3 Binding. Genetics 2019; 213:465-479. [PMID: 31391265 PMCID: PMC6781895 DOI: 10.1534/genetics.119.302528] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 07/19/2019] [Indexed: 12/12/2022] Open
Abstract
Two common features of centromeres are their transcription into noncoding centromere RNAs (cen-RNAs) and their assembly into nucleosomes that contain a centromere-specific histone H3 (cenH3). Here, we show that Saccharomyces cerevisiae cen-RNA was present in low amounts in wild-type (WT) cells, and that its appearance was tightly cell cycle-regulated, appearing and disappearing in a narrow window in S phase after centromere replication. In cells lacking Cbf1, a centromere-binding protein, cen-RNA was 5-12 times more abundant throughout the cell cycle. In WT cells, cen-RNA appearance occurred at the same time as loss of Cbf1's centromere binding, arguing that the physical presence of Cbf1 inhibits cen-RNA production. Binding of the Pif1 DNA helicase, which happens in mid-late S phase, occurred at about the same time as Cbf1 loss from the centromere, suggesting that Pif1 may facilitate this loss by its known ability to displace proteins from DNA. Cen-RNAs were more abundant in rnh1Δ cells but only in mid-late S phase. However, fork pausing at centromeres was not elevated in rnh1Δ cells but rather was due to centromere-binding proteins, including Cbf1 Strains with increased cen-RNA lost centromere plasmids at elevated rates. In cbf1Δ cells, where both the levels and the cell cycle-regulated appearance of cen-RNA were disrupted, the timing and levels of cenH3 centromere binding were perturbed. Thus, cen-RNAs are highly regulated, and disruption of this regulation correlates with changes in centromere structure and function.
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Affiliation(s)
- Chi-Fu Chen
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey 08544
| | - Thomas J Pohl
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey 08544
| | - Angela Chan
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey 08544
| | - Joshua S Slocum
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey 08544
| | - Virginia A Zakian
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, New Jersey 08544
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Wang D, Gao F. Comprehensive Analysis of Replication Origins in Saccharomyces cerevisiae Genomes. Front Microbiol 2019; 10:2122. [PMID: 31572328 PMCID: PMC6753640 DOI: 10.3389/fmicb.2019.02122] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 08/29/2019] [Indexed: 12/15/2022] Open
Abstract
DNA replication initiates from multiple replication origins (ORIs) in eukaryotes. Discovery and characterization of replication origins are essential for a better understanding of the molecular mechanism of DNA replication. In this study, the features of autonomously replicating sequences (ARSs) in Saccharomyces cerevisiae have been comprehensively analyzed as follows. Firstly, we carried out the analysis of the ARSs available in S. cerevisiae S288C. By evaluating the sequence similarity of experimentally established ARSs, we found that 94.32% of ARSs are unique across the whole genome of S. cerevisiae S288C and those with high sequence similarity are prone to locate in subtelomeres. Subsequently, we built a non-redundant dataset with a total of 520 ARSs, which are based on ARSs annotation of S. cerevisiae S288C from SGD and then supplemented with those from OriDB and DeOri databases. We conducted a large-scale comparison of ORIs among the diverse budding yeast strains from a population genomics perspective. We found that 82.7% of ARSs are not only conserved in genomic sequence but also relatively conserved in chromosomal position. The non-conserved ARSs tend to distribute in the subtelomeric regions. We also conducted a pan-genome analysis of ARSs among the S. cerevisiae strains, and a total of 183 core ARSs existing in all yeast strains were determined. We extracted the genes adjacent to replication origins among the 104 yeast strains to examine whether there are differences in their gene functions. The result showed that the genes involved in the initiation of DNA replication, such as orc3, mcm2, mcm4, mcm6, and cdc45, are conservatively located adjacent to the replication origins. Furthermore, we found the genes adjacent to conserved ARSs are significantly enriched in DNA binding, enzyme activity, transportation, and energy, whereas for the genes adjacent to non-conserved ARSs are significantly enriched in response to environmental stress, metabolites biosynthetic process and biosynthesis of antibiotics. In general, we characterized the replication origins from the genome-wide and population genomics perspectives, which would provide new insights into the replication mechanism of S. cerevisiae and facilitate the design of algorithms to identify genome-wide replication origins in yeast.
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Affiliation(s)
- Dan Wang
- Department of Physics, School of Science, Tianjin University, Tianjin, China
| | - Feng Gao
- Department of Physics, School of Science, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, China.,SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China
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Julius J, Peng J, McCulley A, Caridi C, Arnak R, See C, Nugent CI, Feng W, Bachant J. Inhibition of spindle extension through the yeast S phase checkpoint is coupled to replication fork stability and the integrity of centromeric DNA. Mol Biol Cell 2019; 30:2771-2789. [PMID: 31509480 PMCID: PMC6789157 DOI: 10.1091/mbc.e19-03-0156] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Budding yeast treated with hydroxyurea (HU) activate the S phase checkpoint kinase Rad53, which prevents DNA replication forks from undergoing aberrant structural transitions and nuclease processing. Rad53 is also required to prevent premature extension of the mitotic spindle that assembles during a HU-extended S phase. Here we present evidence that checkpoint restraint of spindle extension is directly coupled to Rad53 control of replication fork stability. In budding yeast, centromeres are flanked by replication origins that fire in early S phase. Mutations affecting the Zn2+-finger of Dbf4, an origin activator, preferentially reduce centromere-proximal origin firing in HU, corresponding with suppression of rad53 spindle extension. Inactivating Exo1 nuclease or displacing centromeres from origins provides a similar suppression. Conversely, short-circuiting Rad53 targeting of Dbf4, Sld3, and Dun1, substrates contributing to fork stability, induces spindle extension. These results reveal spindle extension in HU-treated rad53 mutants is a consequence of replication fork catastrophes at centromeres. When such catastrophes occur, centromeres become susceptible to nucleases, disrupting kinetochore function and spindle force balancing mechanisms. At the same time, our data indicate centromere duplication is not required to stabilize S phase spindle structure, leading us to propose a model for how monopolar kinetochore-spindle attachments may contribute to spindle force balance in HU.
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Affiliation(s)
- Jeff Julius
- Department of Molecular Cell Systems Biology, University of California, Riverside, Riverside, CA 92521
| | - Jie Peng
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Andrew McCulley
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Chris Caridi
- Department of Molecular Cell Systems Biology, University of California, Riverside, Riverside, CA 92521
| | - Remigiusz Arnak
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Colby See
- Department of Molecular Cell Systems Biology, University of California, Riverside, Riverside, CA 92521
| | - Constance I Nugent
- Department of Molecular Cell Systems Biology, University of California, Riverside, Riverside, CA 92521
| | - Wenyi Feng
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Jeff Bachant
- Department of Molecular Cell Systems Biology, University of California, Riverside, Riverside, CA 92521
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48
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Hinshaw SM, Dates AN, Harrison SC. The structure of the yeast Ctf3 complex. eLife 2019; 8:e48215. [PMID: 31194673 PMCID: PMC6602579 DOI: 10.7554/elife.48215] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 06/12/2019] [Indexed: 01/07/2023] Open
Abstract
Kinetochores are the chromosomal attachment points for spindle microtubules. They are also signaling hubs that control major cell cycle transitions and coordinate chromosome folding. Most well-studied eukaryotes rely on a conserved set of factors, which are divided among two loosely-defined groups, for these functions. Outer kinetochore proteins contact microtubules or regulate this contact directly. Inner kinetochore proteins designate the kinetochore assembly site by recognizing a specialized nucleosome containing the H3 variant Cse4/CENP-A. We previously determined the structure, resolved by cryo-electron microscopy (cryo-EM), of the yeast Ctf19 complex (Ctf19c, homologous to the vertebrate CCAN), providing a high-resolution view of inner kinetochore architecture (Hinshaw and Harrison, 2019). We now extend these observations by reporting a near-atomic model of the Ctf3 complex, the outermost Ctf19c sub-assembly seen in our original cryo-EM density. The model is sufficiently well-determined by the new data to enable molecular interpretation of Ctf3 recruitment and function.
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Affiliation(s)
- Stephen M Hinshaw
- Department of Biological Chemistry and Molecular PharmacologyHarvard Medical School, Howard Hughes Medical InstituteBostonUnited States
| | - Andrew N Dates
- Harvard Chemical Biology PhD ProgramHarvard UniversityBostonUnited States
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular PharmacologyHarvard Medical School, Howard Hughes Medical InstituteBostonUnited States
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49
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Duriez B, Chilaka S, Bercher JF, Hercul E, Prioleau MN. Replication dynamics of individual loci in single living cells reveal changes in the degree of replication stochasticity through S phase. Nucleic Acids Res 2019; 47:5155-5169. [PMID: 30926993 PMCID: PMC6547449 DOI: 10.1093/nar/gkz220] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/18/2019] [Accepted: 03/21/2019] [Indexed: 12/22/2022] Open
Abstract
Eukaryotic genomes are replicated under the control of a highly sophisticated program during the restricted time period corresponding to S phase. The most widely used replication timing assays, which are performed on populations of millions of cells, suggest that most of the genome is synchronously replicated on homologous chromosomes. We investigated the stochastic nature of this temporal program, by comparing the precise replication times of allelic loci within single vertebrate cells progressing through S phase at six loci replicated from very early to very late. We show that replication timing is strictly controlled for the three loci replicated in the first half of S phase. Out of the three loci replicated in the second part of S phase, two present a significantly more stochastic pattern. Surprisingly, we find that the locus replicated at the very end of S phase, presents stochasticity similar to those replicated in early S phase. We suggest that the richness of loci in efficient origins of replication, which decreases from early- to late-replicating regions, and the strength of interaction with the nuclear lamina may underlie the variation of timing control during S phase.
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Affiliation(s)
- Bénédicte Duriez
- Domaines Chromatiniens et Réplication, Institut Jacques Monod, UMR7592 CNRS – Université Paris Diderot, Paris, France, Equipe labellisée ARC
| | - Sabarinadh Chilaka
- Domaines Chromatiniens et Réplication, Institut Jacques Monod, UMR7592 CNRS – Université Paris Diderot, Paris, France, Equipe labellisée ARC
| | | | - Eslande Hercul
- Domaines Chromatiniens et Réplication, Institut Jacques Monod, UMR7592 CNRS – Université Paris Diderot, Paris, France, Equipe labellisée ARC
| | - Marie-Noëlle Prioleau
- Domaines Chromatiniens et Réplication, Institut Jacques Monod, UMR7592 CNRS – Université Paris Diderot, Paris, France, Equipe labellisée ARC
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50
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Shen KF, Forsburg SL. Overlapping Roles in Chromosome Segregation for Heterochromatin Protein 1 (Swi6) and DDK in Schizosaccharomyces pombe. Genetics 2019; 212:417-430. [PMID: 31000521 PMCID: PMC6553818 DOI: 10.1534/genetics.119.302125] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 04/10/2019] [Indexed: 12/23/2022] Open
Abstract
Fission yeast Swi6 is a human HP1 homolog that plays important roles in multiple cellular processes. In addition to its role in maintaining heterochromatin silencing, Swi6 is required for cohesin enrichment at the pericentromere. Loss of Swi6 leads to abnormal mitosis, including defects in the establishment of bioriented sister kinetochores and microtubule attachment. Swi6 interacts with Dfp1, a regulatory subunit of DBF4-dependent kinase (DDK), and failure to recruit Dfp1 to the pericentromere results in late DNA replication. Using the dfp1-3A mutant allele, which specifically disrupts Swi6-Dfp1 association, we investigated how interaction between Swi6 and Dfp1 affects chromosome dynamics. We find that disrupting the interaction between Swi6 and Dfp1 delays mitotic progression in a spindle assembly checkpoint-dependent manner. Artificially tethering Dfp1 back to the pericentromere is sufficient to restore normal spindle length and rescue segregation defects in swi6-deleted cells. However, Swi6 is necessary for centromeric localization of Rad21-GFP independent of DDK. Our data indicate that DDK contributes to mitotic chromosome segregation in pathways that partly overlap with, but can be separated from both, Swi6 and the other HP1 homolog, Chp2.
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Affiliation(s)
- Kuo-Fang Shen
- Program in Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089-2910
| | - Susan L Forsburg
- Program in Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089-2910
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