1
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Lam WH, Yu D, Zhang Q, Lin Y, Li N, Li J, Wu Y, Zhang Y, Gao N, Tye BK, Zhai Y, Dang S. DNA bending mediated by ORC is essential for replication licensing in budding yeast. Proc Natl Acad Sci U S A 2025; 122:e2502277122. [PMID: 40184174 PMCID: PMC12002289 DOI: 10.1073/pnas.2502277122] [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: 01/29/2025] [Accepted: 03/04/2025] [Indexed: 04/05/2025] Open
Abstract
In eukaryotes, the origin recognition complex (ORC) promotes the assembly of minichromosome maintenance 2 to 7 complexes into a head-to-head double hexamer at origin DNA in a process known as replication licensing. In this study, we present a series of cryoelectron microscopy structures of yeast ORC mutants in complex with origin DNA. We show that Orc6, the smallest subunit of ORC, utilizes its transcription factor II B-B domain to orchestrate the sequential binding of ORC to origin DNA. In addition, Orc6 plays the role of a scaffold by stabilizing the basic patch (BP) of Orc5 for ORC to capture and bend origin DNA. Importantly, disrupting DNA bending through mutating three key residues in Orc5-BP impairs ORC's ability to promote replication initiation at two points during the pre-RC assembly process. This study dissects the multifaceted role of Orc6 in orchestrating ORC's activities on DNA and underscores the vital role of DNA bending by ORC in replication licensing.
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Grants
- 32425014 MOST | National Natural Science Foundation of China (NSFC)
- GRF17119022 Research Grants Council, University Grants Committee (ç"究資助局)
- GRF17109623 Research Grants Council, University Grants Committee (ç"究資助局)
- C6036-21GF Research Grants Council, University Grants Committee (ç"究資助局)
- C7035-23GF Research Grants Council, University Grants Committee (ç"究資助局)
- CRS_HKU705/23 Research Grants Council, University Grants Committee (ç"究資助局)
- GRF16103321 Research Grants Council, University Grants Committee (ç"究資助局)
- GRF16102822 Research Grants Council, University Grants Committee (ç"究資助局)
- GRF16100233 Research Grants Council, University Grants Committee (ç"究資助局)
- C6001-21E Research Grants Council, University Grants Committee (ç"究資助局)
- C6012-22G Research Grants Council, University Grants Committee (ç"究資助局)
- Research Grants Council, University Grants Committee (ç”究資助局)
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Affiliation(s)
- Wai Hei Lam
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Daqi Yu
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Qiongdan Zhang
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Yuhan Lin
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Ningning Li
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing100084, China
| | - Jian Li
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Yue Wu
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Yingyi Zhang
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Ning Gao
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing100084, China
| | - Bik Kwoon Tye
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - Yuanliang Zhai
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Shangyu Dang
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
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2
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Stępień K, Enkhbaatar T, Kula-Maximenko M, Jurczyk Ł, Skoneczna A, Mołoń M. Restricting the level of the proteins essential for the regulation of the initiation step of replication extends the chronological lifespan and reproductive potential in budding yeast. Biogerontology 2024; 25:859-881. [PMID: 38844751 PMCID: PMC11374879 DOI: 10.1007/s10522-024-10113-x] [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: 03/22/2024] [Accepted: 05/29/2024] [Indexed: 09/05/2024]
Abstract
Aging is defined as a progressive decline in physiological integrity, leading to impaired biological function, including fertility, and rising vulnerability to death. Disorders of DNA replication often lead to replication stress and are identified as factors influencing the aging rate. In this study, we aimed to reveal how the cells that lost strict control of the formation of crucial for replication initiation a pre-initiation complex impact the cells' physiology and aging. As strains with the lower pre-IC control (lowPICC) we used, Saccharomyces cerevisiae heterozygous strains having only one functional copy of genes, encoding essential replication proteins such as Cdc6, Dbf4, Sld3, Sld7, Sld2, and Mcm10. The lowPICC strains exhibited a significant reduction in the respective genes' mRNA levels, causing cell cycle aberrations and doubling time extensions. Additionally, the reduced expression of the lowPICC genes led to an aberrant DNA damage response, affected cellular and mitochondrial DNA content, extended the lifespan of post-mitotic cells, and increased the yeast's reproductive potential. Importantly, we also demonstrated a strong negative correlation between the content of cellular macromolecules (RNA, proteins, lipids, polysaccharides) and aging. The data presented here will likely contribute to the future development of therapies for treating various human diseases.
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Affiliation(s)
- Karolina Stępień
- Institute of Medical Sciences, Rzeszów University, 35-959, Rzeszów, Poland
| | - Tuguldur Enkhbaatar
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106, Warsaw, Poland
| | - Monika Kula-Maximenko
- The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, 30-239, Krakow, Poland
| | - Łukasz Jurczyk
- Institute of Agricultural Sciences, Rzeszów University, 35-601, Rzeszów, Poland
| | - Adrianna Skoneczna
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106, Warsaw, Poland.
| | - Mateusz Mołoń
- Institute of Biology, Rzeszów University, 35-601, Rzeszów, Poland.
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3
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Chappleboim M, Naveh-Tassa S, Carmi M, Levy Y, Barkai N. Ordered and disordered regions of the Origin Recognition Complex direct differential in vivo binding at distinct motif sequences. Nucleic Acids Res 2024; 52:5720-5731. [PMID: 38597680 PMCID: PMC11162778 DOI: 10.1093/nar/gkae249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 03/16/2024] [Accepted: 04/09/2024] [Indexed: 04/11/2024] Open
Abstract
The Origin Recognition Complex (ORC) seeds replication-fork formation by binding to DNA replication origins, which in budding yeast contain a 17bp DNA motif. High resolution structure of the ORC-DNA complex revealed two base-interacting elements: a disordered basic patch (Orc1-BP4) and an insertion helix (Orc4-IH). To define the ORC elements guiding its DNA binding in vivo, we mapped genomic locations of 38 designed ORC mutants, revealing that different ORC elements guide binding at different sites. At silencing-associated sites lacking the motif, ORC binding and activity were fully explained by a BAH domain. Within replication origins, we reveal two dominating motif variants showing differential binding modes and symmetry: a non-repetitive motif whose binding requires Orc1-BP4 and Orc4-IH, and a repetitive one where another basic patch, Orc1-BP3, can replace Orc4-IH. Disordered basic patches are therefore key for ORC-motif binding in vivo, and we discuss how these conserved, minor-groove interacting elements can guide specific ORC-DNA recognition.
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Affiliation(s)
- Michal Chappleboim
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Segev Naveh-Tassa
- Department of Chemical and structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Miri Carmi
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Yaakov Levy
- Department of Chemical and structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Naama Barkai
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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4
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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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5
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Zhang A, Friedman LJ, Gelles J, Bell SP. Changing protein-DNA interactions promote ORC binding site exchange during replication origin licensing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.16.545300. [PMID: 37398123 PMCID: PMC10312730 DOI: 10.1101/2023.06.16.545300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
During origin licensing, the eukaryotic replicative helicase Mcm2-7 forms head-to-head double hexamers to prime origins for bidirectional replication. Recent single-molecule and structural studies revealed that one molecule of the helicase loader ORC can sequentially load two Mcm2-7 hexamers to ensure proper head-to-head helicase alignment. To perform this task, ORC must release from its initial high-affinity DNA binding site and "flip" to bind a weaker, inverted DNA site. However, the mechanism of this binding-site switch remains unclear. In this study, we used single-molecule Förster resonance energy transfer (sm-FRET) to study the changing interactions between DNA and ORC or Mcm2-7. We found that the loss of DNA bending that occurs during DNA deposition into the Mcm2-7 central channel increases the rate of ORC dissociation from DNA. Further studies revealed temporally-controlled DNA sliding of helicase-loading intermediates, and that the first sliding complex includes ORC, Mcm2-7, and Cdt1. We demonstrate that sequential events of DNA unbending, Cdc6 release, and sliding lead to a stepwise decrease in ORC stability on DNA, facilitating ORC dissociation from its strong binding site during site switching. In addition, the controlled sliding we observed provides insight into how ORC accesses secondary DNA binding sites at different locations relative to the initial binding site. Our study highlights the importance of dynamic protein-DNA interactions in the loading of two oppositely-oriented Mcm2-7 helicases to ensure bidirectional DNA replication. Significance Statement Bidirectional DNA replication, in which two replication forks travel in opposite directions from each origin of replication, is required for complete genome duplication. To prepare for this event, two copies of the Mcm2-7 replicative helicase are loaded at each origin in opposite orientations. Using single-molecule assays, we studied the sequence of changing protein-DNA interactions involved in this process. These stepwise changes gradually reduce the DNA-binding strength of ORC, the primary DNA binding protein involved in this event. This reduced affinity promotes ORC dissociation and rebinding in the opposite orientation on the DNA, facilitating the sequential assembly of two Mcm2-7 molecules in opposite orientations. Our findings identify a coordinated series of events that drive proper DNA replication initiation.
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Affiliation(s)
- Annie Zhang
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Larry J. Friedman
- Department of Biochemistry, Brandeis University, Waltham, MA 02454, USA
| | - Jeff Gelles
- Department of Biochemistry, Brandeis University, Waltham, MA 02454, USA
| | - Stephen P Bell
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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6
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Weiβ M, Chanou A, Schauer T, Tvardovskiy A, Meiser S, König AC, Schmidt T, Kruse E, Ummethum H, Trauner M, Werner M, Lalonde M, Hauck SM, Scialdone A, Hamperl S. Single-copy locus proteomics of early- and late-firing DNA replication origins identifies a role of Ask1/DASH complex in replication timing control. Cell Rep 2023; 42:112045. [PMID: 36701236 PMCID: PMC9989823 DOI: 10.1016/j.celrep.2023.112045] [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: 03/04/2022] [Revised: 11/28/2022] [Accepted: 01/13/2023] [Indexed: 01/27/2023] Open
Abstract
The chromatin environment at origins of replication is thought to influence DNA replication initiation in eukaryotic genomes. However, it remains unclear how and which chromatin features control the firing of early-efficient (EE) or late-inefficient (LI) origins. Here, we use site-specific recombination and single-locus chromatin isolation to purify EE and LI replication origins in Saccharomyces cerevisiae. Using mass spectrometry, we define the protein composition of native chromatin regions surrounding the EE and LI replication start sites. In addition to known origin interactors, we find the microtubule-binding Ask1/DASH complex as an origin-regulating factor. Strikingly, tethering of Ask1 to individual origin sites advances replication timing (RT) of the targeted chromosomal domain. Targeted degradation of Ask1 globally changes RT of a subset of origins, which can be reproduced by inhibiting microtubule dynamics. Thus, our findings mechanistically connect RT and chromosomal organization via Ask1/DASH with the microtubule cytoskeleton.
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Affiliation(s)
- Matthias Weiβ
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany
| | - Anna Chanou
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany
| | - Tamas Schauer
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany
| | - Andrey Tvardovskiy
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Stefan Meiser
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany; Institute of Functional Epigenetics, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany; Institute of Computational Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Ann-Christine König
- Metabolomics and Proteomics Core, Helmholtz Zentrum München, German Center for Environmental Health, Heidemannstrasse 1, 80939 München, Germany
| | - Tobias Schmidt
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany
| | - Elisabeth Kruse
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany
| | - Henning Ummethum
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany
| | - Manuel Trauner
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany
| | - Marcel Werner
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany
| | - Maxime Lalonde
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany
| | - Stefanie M Hauck
- Metabolomics and Proteomics Core, Helmholtz Zentrum München, German Center for Environmental Health, Heidemannstrasse 1, 80939 München, Germany
| | - Antonio Scialdone
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany; Institute of Functional Epigenetics, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany; Institute of Computational Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Stephan Hamperl
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Feodor-Lynen-Strasse 21, 81377 München, Germany.
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7
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Stępień K, Skoneczna A, Kula-Maximenko M, Jurczyk Ł, Mołoń M. Depletion of the Origin Recognition Complex Subunits Delays Aging in Budding Yeast. Cells 2022; 11:cells11081252. [PMID: 35455932 PMCID: PMC9032818 DOI: 10.3390/cells11081252] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/31/2022] [Accepted: 04/05/2022] [Indexed: 12/01/2022] Open
Abstract
Precise DNA replication is pivotal for ensuring the accurate inheritance of genetic information. To avoid genetic instability, each DNA fragment needs to be amplified only once per cell cycle. DNA replication in eukaryotes starts with the binding of the origin recognition complex (ORC) to the origins of DNA replication. The genes encoding ORC subunits have been conserved across eukaryotic evolution and are essential for the initiation of DNA replication. In this study, we conducted an extensive physiological and aging-dependent analysis of heterozygous cells lacking one copy of ORC genes in the BY4743 background. Cells with only one copy of the ORC genes showed a significant decrease in the level of ORC mRNA, a delay in the G1 phase of the cell cycle, and an extended doubling time. Here, we also show that the reducing the levels of Orc1-6 proteins significantly extends both the budding and average chronological lifespans. Heterozygous ORC/orcΔ and wild-type diploid cells easily undergo haploidization during chronological aging. This ploidy shift might be related to nutrient starvation or the inability to survive under stress conditions. A Raman spectroscopy analysis helped us to strengthen the hypothesis of the importance of lipid metabolism and homeostasis in aging.
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Affiliation(s)
- Karolina Stępień
- Department of Biology, Institute of Biology and Biotechnology, University of Rzeszów, 35-601 Rzeszów, Poland;
| | - Adrianna Skoneczna
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Correspondence: (A.S.); (M.M.); Tel.: +48-22-659-70-72 (A.S.); +48-17-785-54-07 (M.M.)
| | - Monika Kula-Maximenko
- The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, 30-239 Krakow, Poland;
| | - Łukasz Jurczyk
- Institute of Agricultural Sciences, Land Management and Environmental Protection, University of Rzeszow, 35-601 Rzeszów, Poland;
| | - Mateusz Mołoń
- Department of Biology, Institute of Biology and Biotechnology, University of Rzeszów, 35-601 Rzeszów, Poland;
- Correspondence: (A.S.); (M.M.); Tel.: +48-22-659-70-72 (A.S.); +48-17-785-54-07 (M.M.)
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8
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Abstract
DNA replication in eukaryotic cells initiates from large numbers of sites called replication origins. Initiation of replication from these origins must be tightly controlled to ensure the entire genome is precisely duplicated in each cell cycle. This is accomplished through the regulation of the first two steps in replication: loading and activation of the replicative DNA helicase. Here we describe what is known about the mechanism and regulation of these two reactions from a genetic, biochemical, and structural perspective, focusing on recent progress using proteins from budding yeast. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Alessandro Costa
- Macromolecular Machines Laboratory, The Francis Crick Institute, London, UK;
| | - John F X Diffley
- Chromosome Replication Laboratory, The Francis Crick Institute, London, UK;
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9
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Joshi I, Peng J, Alvino G, Kwan E, Feng W. Exceptional origin activation revealed by comparative analysis in two laboratory yeast strains. PLoS One 2022; 17:e0263569. [PMID: 35157703 PMCID: PMC8843211 DOI: 10.1371/journal.pone.0263569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 01/21/2022] [Indexed: 11/18/2022] Open
Abstract
We performed a comparative analysis of replication origin activation by genome-wide single-stranded DNA mapping in two yeast strains challenged by hydroxyurea, an inhibitor of the ribonucleotide reductase. We gained understanding of the impact on origin activation by three factors: S-phase checkpoint control, DNA sequence polymorphisms, and relative positioning of origin and transcription unit. Wild type W303 showed a significant reduction of fork progression accompanied by an elevated level of Rad53 phosphorylation as well as physical presence at origins compared to A364a. Moreover, a rad53K227A mutant in W303 activated more origins, accompanied by global reduction of ssDNA across all origins, compared to A364a. Sequence polymorphism in the consensus motifs of origins plays a minor role in determining strain-specific activity. Finally, we identified a new class of origins only active in checkpoint-proficient cells, which we named “Rad53-dependent origins”. Our study presents a comprehensive list of differentially used origins and provide new insights into the mechanisms of origin activation.
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Affiliation(s)
- Ishita Joshi
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, United States of America
| | - Jie Peng
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, United States of America
| | - Gina Alvino
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Elizabeth Kwan
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Wenyi Feng
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, United States of America
- * E-mail:
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10
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ReconSil: An electron microscopy toolbox to study helicase function at an origin of replication. Methods Enzymol 2022; 672:203-231. [DOI: 10.1016/bs.mie.2022.03.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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11
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The structure of ORC-Cdc6 on an origin DNA reveals the mechanism of ORC activation by the replication initiator Cdc6. Nat Commun 2021; 12:3883. [PMID: 34162887 PMCID: PMC8222357 DOI: 10.1038/s41467-021-24199-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 06/07/2021] [Indexed: 01/31/2023] Open
Abstract
The Origin Recognition Complex (ORC) binds to sites in chromosomes to specify the location of origins of DNA replication. The S. cerevisiae ORC binds to specific DNA sequences throughout the cell cycle but becomes active only when it binds to the replication initiator Cdc6. It has been unclear at the molecular level how Cdc6 activates ORC, converting it to an active recruiter of the Mcm2-7 hexamer, the core of the replicative helicase. Here we report the cryo-EM structure at 3.3 Å resolution of the yeast ORC–Cdc6 bound to an 85-bp ARS1 origin DNA. The structure reveals that Cdc6 contributes to origin DNA recognition via its winged helix domain (WHD) and its initiator-specific motif. Cdc6 binding rearranges a short α-helix in the Orc1 AAA+ domain and the Orc2 WHD, leading to the activation of the Cdc6 ATPase and the formation of the three sites for the recruitment of Mcm2-7, none of which are present in ORC alone. The results illuminate the molecular mechanism of a critical biochemical step in the licensing of eukaryotic replication origins. Eukaryotic DNA replication is mediated by many proteins which are tightly regulated for an efficient firing of replication at each cell cycle. Here the authors report a cryo-EM structure of the yeast ORC–Cdc6 bound to an 85-bp ARS1 origin DNA revealing additional insights into how Cdc6 contributes to origin DNA recognition.
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12
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Investigation of the Interaction of Human Origin Recognition Complex Subunit 1 with G-Quadruplex DNAs of Human c-myc Promoter and Telomere Regions. Int J Mol Sci 2021; 22:ijms22073481. [PMID: 33801762 PMCID: PMC8036949 DOI: 10.3390/ijms22073481] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/19/2021] [Accepted: 03/23/2021] [Indexed: 12/15/2022] Open
Abstract
Origin recognition complex (ORC) binds to replication origins in eukaryotic DNAs and plays an important role in replication. Although yeast ORC is known to sequence-specifically bind to a replication origin, how human ORC recognizes a replication origin remains unknown. Previous genome-wide studies revealed that guanine (G)-rich sequences, potentially forming G-quadruplex (G4) structures, are present in most replication origins in human cells. We previously suggested that the region comprising residues 413–511 of human ORC subunit 1, hORC1413–511, binds preferentially to G-rich DNAs, which form a G4 structure in the absence of hORC1413–511. Here, we investigated the interaction of hORC1413-511 with various G-rich DNAs derived from human c-myc promoter and telomere regions. Fluorescence anisotropy revealed that hORC1413–511 binds preferentially to DNAs that have G4 structures over ones having double-stranded structures. Importantly, circular dichroism (CD) and nuclear magnetic resonance (NMR) showed that those G-rich DNAs retain the G4 structures even after binding with hORC1413–511. NMR chemical shift perturbation analyses revealed that the external G-tetrad planes of the G4 structures are the primary binding sites for hORC1413–511. The present study suggests that human ORC1 may recognize replication origins through the G4 structure.
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13
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Amin A, Wu R, Cheung MH, Scott JF, Wang Z, Zhou Z, Liu C, Zhu G, Wong CKC, Yu Z, Liang C. An Essential and Cell-Cycle-Dependent ORC Dimerization Cycle Regulates Eukaryotic Chromosomal DNA Replication. Cell Rep 2021; 30:3323-3338.e6. [PMID: 32160540 DOI: 10.1016/j.celrep.2020.02.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 10/04/2019] [Accepted: 02/10/2020] [Indexed: 12/24/2022] Open
Abstract
Eukaryotic DNA replication licensing is a prerequisite for, and plays a role in, regulating genome duplication that occurs exactly once per cell cycle. ORC (origin recognition complex) binds to and marks replication origins throughout the cell cycle and loads other replication-initiation proteins onto replication origins to form pre-replicative complexes (pre-RCs), completing replication licensing. However, how an asymmetric single-heterohexameric ORC structure loads the symmetric MCM (minichromosome maintenance) double hexamers is controversial, and importantly, it remains unknown when and how ORC proteins associate with the newly replicated origins to protect them from invasion by histones. Here, we report an essential and cell-cycle-dependent ORC "dimerization cycle" that plays three fundamental roles in the regulation of DNA replication: providing a symmetric platform to load the symmetric pre-RCs, marking and protecting the nascent sister replication origins for the next licensing, and playing a crucial role to prevent origin re-licensing within the same cell cycle.
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Affiliation(s)
- Aftab Amin
- School of Chinese Medicine and Department of Biology, Hong Kong Baptist University, Hong Kong, China; Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Rentian Wu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Man Hei Cheung
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - John F Scott
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Ziyi Wang
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Zijing Zhou
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Changdong Liu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Guang Zhu
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Chris Kong-Chu Wong
- School of Chinese Medicine and Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Zhiling Yu
- School of Chinese Medicine and Department of Biology, Hong Kong Baptist University, Hong Kong, China.
| | - Chun Liang
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China; The First Clinical Medicine College, Guangzhou University of Chinese Medicine, Guangzhou, China; EnKang Pharmaceuticals Limited, Guangzhou, China.
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14
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Chou HC, Bhalla K, Demerdesh OE, Klingbeil O, Hanington K, Aganezov S, Andrews P, Alsudani H, Chang K, Vakoc CR, Schatz MC, McCombie WR, Stillman B. The human origin recognition complex is essential for pre-RC assembly, mitosis, and maintenance of nuclear structure. eLife 2021; 10:61797. [PMID: 33522487 PMCID: PMC7877914 DOI: 10.7554/elife.61797] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 01/30/2021] [Indexed: 12/23/2022] Open
Abstract
The origin recognition complex (ORC) cooperates with CDC6, MCM2-7, and CDT1 to form pre-RC complexes at origins of DNA replication. Here, using tiling-sgRNA CRISPR screens, we report that each subunit of ORC and CDC6 is essential in human cells. Using an auxin-inducible degradation system, we created stable cell lines capable of ablating ORC2 rapidly, revealing multiple cell division cycle phenotypes. The primary defects in the absence of ORC2 were cells encountering difficulty in initiating DNA replication or progressing through the cell division cycle due to reduced MCM2-7 loading onto chromatin in G1 phase. The nuclei of ORC2-deficient cells were also large, with decompacted heterochromatin. Some ORC2-deficient cells that completed DNA replication entered into, but never exited mitosis. ORC1 knockout cells also demonstrated extremely slow cell proliferation and abnormal cell and nuclear morphology. Thus, ORC proteins and CDC6 are indispensable for normal cellular proliferation and contribute to nuclear organization.
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Affiliation(s)
- Hsiang-Chen Chou
- Cold Spring Harbor Laboratory, Cold Spring Harbor, United States.,Graduate Program in Molecular and Cellular Biology, Stony Brook University, Stony Brook, United States
| | - Kuhulika Bhalla
- Cold Spring Harbor Laboratory, Cold Spring Harbor, United States
| | | | - Olaf Klingbeil
- Cold Spring Harbor Laboratory, Cold Spring Harbor, United States
| | | | - Sergey Aganezov
- Department of Computer Science, Whiting School of Engineering, Johns Hopkins University, Baltimore, United States
| | - Peter Andrews
- Cold Spring Harbor Laboratory, Cold Spring Harbor, United States
| | - Habeeb Alsudani
- Cold Spring Harbor Laboratory, Cold Spring Harbor, United States
| | - Kenneth Chang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, United States
| | | | - Michael C Schatz
- Department of Computer Science, Whiting School of Engineering, Johns Hopkins University, Baltimore, United States
| | | | - Bruce Stillman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, United States
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15
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Prospect of reprogramming replication licensing for cancer drug development. Biomed Pharmacother 2021; 136:111190. [PMID: 33497909 DOI: 10.1016/j.biopha.2020.111190] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 12/15/2020] [Accepted: 12/26/2020] [Indexed: 12/15/2022] Open
Abstract
Eukaryotic chromosomal DNA replication is preceded by replication licensing which involves the identification of the origin of replication by origin recognition complex (ORC). The ORC loads pre-replication complexes (pre-RCs) through a series of tightly regulated mechanisms where the ORC interacts with Cdc6 to recruit cdt1-MCM2-7 complexes to the origin of replication. In eukaryotes, adherence to regulatory mechanisms of the replication program is required to ensure that all daughter cells carry the exact copy of genetic material as the parent cell. Failure of which leads to the development of genome instability syndromes like cancer, diabetes, etc. In an event of such occurrence, preventing cells from carrying the defaulted genetic material and passing it to other cells hinges on the regulation of chromosomal DNA replication. Thus, understanding the mechanisms underpinning chromosomal DNA replication and particularly replication licensing can expose druggable enzymes, effector molecules, and secondary messengers that can be targeted for diagnosis and therapeutic purposes. Effectively drugging these molecular markers to reprogram pre-replication events can be used to control the fate of chromosomal DNA replication for the treatment of genome instability disorders and in this case, cancer. This review discusses available knowledge of replication licensing in the contest of molecular drug discovery for the treatment of cancer.
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16
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Tareen A, Kinney JB. Logomaker: beautiful sequence logos in Python. Bioinformatics 2020; 36:2272-2274. [PMID: 31821414 PMCID: PMC7141850 DOI: 10.1093/bioinformatics/btz921] [Citation(s) in RCA: 257] [Impact Index Per Article: 51.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 11/14/2019] [Accepted: 12/06/2019] [Indexed: 01/09/2023] Open
Abstract
Summary Sequence logos are visually compelling ways of illustrating the biological properties of DNA, RNA and protein sequences, yet it is currently difficult to generate and customize such logos within the Python programming environment. Here we introduce Logomaker, a Python API for creating publication-quality sequence logos. Logomaker can produce both standard and highly customized logos from either a matrix-like array of numbers or a multiple-sequence alignment. Logos are rendered as native matplotlib objects that are easy to stylize and incorporate into multi-panel figures. Availability and implementation Logomaker can be installed using the pip package manager and is compatible with both Python 2.7 and Python 3.6. Documentation is provided at http://logomaker.readthedocs.io; source code is available at http://github.com/jbkinney/logomaker.
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Affiliation(s)
- Ammar Tareen
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Justin B Kinney
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
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17
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Structural mechanism for replication origin binding and remodeling by a metazoan origin recognition complex and its co-loader Cdc6. Nat Commun 2020; 11:4263. [PMID: 32848132 PMCID: PMC7450096 DOI: 10.1038/s41467-020-18067-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/03/2020] [Indexed: 12/11/2022] Open
Abstract
Eukaryotic DNA replication initiation relies on the origin recognition complex (ORC), a DNA-binding ATPase that loads the Mcm2–7 replicative helicase onto replication origins. Here, we report cryo-electron microscopy (cryo-EM) structures of DNA-bound Drosophila ORC with and without the co-loader Cdc6. These structures reveal that Orc1 and Orc4 constitute the primary DNA binding site in the ORC ring and cooperate with the winged-helix domains to stabilize DNA bending. A loop region near the catalytic Walker B motif of Orc1 directly contacts DNA, allosterically coupling DNA binding to ORC’s ATPase site. Correlating structural and biochemical data show that DNA sequence modulates DNA binding and remodeling by ORC, and that DNA bending promotes Mcm2–7 loading in vitro. Together, these findings explain the distinct DNA sequence-dependencies of metazoan and S. cerevisiae initiators in origin recognition and support a model in which DNA geometry and bendability contribute to Mcm2–7 loading site selection in metazoans. The origin recognition complex (ORC) is essential for loading the Mcm2–7 replicative helicase onto DNA during DNA replication initiation. Here, the authors describe several cryo-electron microscopy structures of Drosophila ORC bound to DNA and its cofactor Cdc6 and also report an in vitro reconstitution system for Drosophila Mcm2–7 loading, revealing unexpected features of ORC’s DNA binding and remodeling mechanism during Mcm2–7 loading.
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18
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Jaremko MJ, On KF, Thomas DR, Stillman B, Joshua-Tor L. The dynamic nature of the human origin recognition complex revealed through five cryoEM structures. eLife 2020; 9:e58622. [PMID: 32808929 PMCID: PMC7467728 DOI: 10.7554/elife.58622] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/17/2020] [Indexed: 12/21/2022] Open
Abstract
Genome replication is initiated from specific origin sites established by dynamic events. The Origin Recognition Complex (ORC) is necessary for orchestrating the initiation process by binding to origin DNA, recruiting CDC6, and assembling the MCM replicative helicase on DNA. Here we report five cryoEM structures of the human ORC (HsORC) that illustrate the native flexibility of the complex. The absence of ORC1 revealed a compact, stable complex of ORC2-5. Introduction of ORC1 opens the complex into several dynamic conformations. Two structures revealed dynamic movements of the ORC1 AAA+ and ORC2 winged-helix domains that likely impact DNA incorporation into the ORC core. Additional twist and pinch motions were observed in an open ORC conformation revealing a hinge at the ORC5·ORC3 interface that may facilitate ORC binding to DNA. Finally, a structure of ORC was determined with endogenous DNA bound in the core revealing important differences between human and yeast origin recognition.
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Affiliation(s)
- Matt J Jaremko
- W. M. Keck Structural Biology LaboratoryNew YorkUnited States
- Howard Hughes Medical InstituteNew YorkUnited States
- Cold Spring Harbor LaboratoryNew YorkUnited States
| | - Kin Fan On
- W. M. Keck Structural Biology LaboratoryNew YorkUnited States
- Howard Hughes Medical InstituteNew YorkUnited States
- Cold Spring Harbor LaboratoryNew YorkUnited States
| | - Dennis R Thomas
- W. M. Keck Structural Biology LaboratoryNew YorkUnited States
- Cold Spring Harbor LaboratoryNew YorkUnited States
| | | | - Leemor Joshua-Tor
- W. M. Keck Structural Biology LaboratoryNew YorkUnited States
- Howard Hughes Medical InstituteNew YorkUnited States
- Cold Spring Harbor LaboratoryNew YorkUnited States
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19
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Masuda K, Renard-Guillet C, Shirahige K, Sutani T. Bioinformatical dissection of fission yeast DNA replication origins. Open Biol 2020; 10:200052. [PMID: 32692956 PMCID: PMC7574548 DOI: 10.1098/rsob.200052] [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] [Indexed: 11/24/2022] Open
Abstract
Replication origins in eukaryotes form a base for assembly of the pre-replication complex (pre-RC), thereby serving as an initiation site of DNA replication. Characteristics of replication origin vary among species. In fission yeast Schizosaccharomyces pombe, DNA of high AT content is a distinct feature of replication origins; however, it remains to be understood what the general molecular architecture of fission yeast origin is. Here, we performed ChIP-seq mapping of Orc4 and Mcm2, two representative components of the pre-RC, and described the characteristics of their binding sites. The analysis revealed that fission yeast efficient origins are associated with two similar but independent features: a ≥15 bp-long motif with stretches of As and an AT-rich region of a few hundred bp. The A-rich motif was correlated with chromosomal binding of Orc, a DNA-binding component in the pre-RC, whereas the AT-rich region was associated with efficient binding of the DNA replicative helicase Mcm. These two features, in combination with the third feature, a transcription-poor region of approximately 1 kb, enabled to distinguish efficient replication origins from the rest of chromosome arms with high accuracy. This study, hence, provides a model that describes how multiple functional elements specify DNA replication origins in fission yeast genome.
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Affiliation(s)
- Koji Masuda
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Claire Renard-Guillet
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Katsuhiko Shirahige
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Takashi Sutani
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
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20
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Do DT, Le NQK. Using extreme gradient boosting to identify origin of replication in Saccharomyces cerevisiae via hybrid features. Genomics 2020; 112:2445-2451. [PMID: 31987913 DOI: 10.1016/j.ygeno.2020.01.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 01/12/2020] [Accepted: 01/23/2020] [Indexed: 12/11/2022]
Abstract
DNA replication is a fundamental task that plays a crucial role in the propagation of all living things on earth. Hence, the accurate identification of its origin could be the key to giving an insightful understanding of the regulatory mechanism of gene expression. Indeed, with the robust development of computational techniques and the abundant biological sequencing data, it has become possible for scientists to identify the origin of replication accurately and promptly. This growing concern has drawn a lot of attention among experts in this field. However, to gain better outcomes, more work is required. Therefore, this study is designed to explore the combination of state-of-the-art features and extreme gradient boosting learning system in classifying DNA sequences. Our hybrid approach is able to identify the origin of DNA replication with achieved sensitivity of 85.19%, specificity of 93.83%, accuracy of 89.51%, and MCC of 0.7931. Evidence is presented to show that our proposed method is superior to the state-of-the-art methods on the same benchmark dataset. Moreover, the research results represent a further step towards developing the prediction models for DNA replication in particular and DNA sequences in general.
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Affiliation(s)
- Duyen Thi Do
- Toxicology and Biomedicine Research Group, Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Viet Nam.
| | - Nguyen Quoc Khanh Le
- Professional Master Program in Artificial Intelligence in Medicine, College of Medicine, Taipei Medical University, Taipei City 106, Taiwan; Research Center of Artificial Intelligence in Medicine, Taipei Medical University, Taipei City 106, Taiwan.
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21
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Abstract
In all kingdoms of life, DNA is used to encode hereditary information. Propagation of the genetic material between generations requires timely and accurate duplication of DNA by semiconservative replication prior to cell division to ensure each daughter cell receives the full complement of chromosomes. DNA synthesis of daughter strands starts at discrete sites, termed replication origins, and proceeds in a bidirectional manner until all genomic DNA is replicated. Despite the fundamental nature of these events, organisms have evolved surprisingly divergent strategies that control replication onset. Here, we discuss commonalities and differences in replication origin organization and recognition in the three domains of life.
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Affiliation(s)
- Babatunde Ekundayo
- Quantitative Biology, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Franziska Bleichert
- Quantitative Biology, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- * E-mail:
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22
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Candelli T, Gros J, Libri D. Pervasive transcription fine-tunes replication origin activity. eLife 2018; 7:40802. [PMID: 30556807 PMCID: PMC6314782 DOI: 10.7554/elife.40802] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 12/17/2018] [Indexed: 12/22/2022] Open
Abstract
RNA polymerase (RNAPII) transcription occurs pervasively, raising the important question of its functional impact on other DNA-associated processes, including replication. In budding yeast, replication originates from Autonomously Replicating Sequences (ARSs), generally located in intergenic regions. The influence of transcription on ARSs function has been studied for decades, but these earlier studies have neglected the role of non-annotated transcription. We studied the relationships between pervasive transcription and replication origin activity using high-resolution transcription maps. We show that ARSs alter the pervasive transcription landscape by pausing and terminating neighboring RNAPII transcription, thus limiting the occurrence of pervasive transcription within origins. We propose that quasi-symmetrical binding of the ORC complex to ARS borders and/or pre-RC formation are responsible for pausing and termination. We show that low, physiological levels of pervasive transcription impact the function of replication origins. Overall, our results have important implications for understanding the impact of genomic location on origin function.
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Affiliation(s)
- Tito Candelli
- Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Julien Gros
- Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Domenico Libri
- Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
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23
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Dao FY, Lv H, Wang F, Feng CQ, Ding H, Chen W, Lin H. Identify origin of replication in Saccharomyces cerevisiae using two-step feature selection technique. Bioinformatics 2018; 35:2075-2083. [DOI: 10.1093/bioinformatics/bty943] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/06/2018] [Accepted: 11/13/2018] [Indexed: 02/07/2023] Open
Affiliation(s)
- Fu-Ying Dao
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology and Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China
| | - Hao Lv
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology and Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China
| | - Fang Wang
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology and Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China
| | - Chao-Qin Feng
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology and Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China
| | - Hui Ding
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology and Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China
| | - Wei Chen
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology and Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China
- Innovative Institute of Chinese Medicine and Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Hao Lin
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology and Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China
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24
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Caruso JA, Duong MT, Carey JPW, Hunt KK, Keyomarsi K. Low-Molecular-Weight Cyclin E in Human Cancer: Cellular Consequences and Opportunities for Targeted Therapies. Cancer Res 2018; 78:5481-5491. [PMID: 30194068 PMCID: PMC6168358 DOI: 10.1158/0008-5472.can-18-1235] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/18/2018] [Accepted: 07/18/2018] [Indexed: 01/03/2023]
Abstract
Cyclin E, a regulatory subunit of cyclin-dependent kinase 2 (CDK2), is central to the initiation of DNA replication at the G1/S checkpoint. Tight temporal control of cyclin E is essential to the coordination of cell-cycle processes and the maintenance of genome integrity. Overexpression of cyclin E in human tumors was first observed in the 1990s and led to the identification of oncogenic roles for deregulated cyclin E in experimental models. A decade later, low-molecular-weight cyclin E (LMW-E) isoforms were observed in aggressive tumor subtypes. Compared with full-length cyclin E, LMW-E hyperactivates CDK2 through increased complex stability and resistance to the endogenous inhibitors p21CIP1 and p27KIP1 LMW-E is predominantly generated by neutrophil elastase-mediated proteolytic cleavage, which eliminates the N-terminal cyclin E nuclear localization signal and promotes cyclin E's accumulation in the cytoplasm. Compared with full-length cyclin E, the aberrant localization and unique stereochemistry of LMW-E dramatically alters the substrate specificity and selectivity of CDK2, increasing tumorigenicity in experimental models. Cytoplasmic LMW-E, which can be assessed by IHC, is prognostic of poor survival and predicts resistance to standard therapies in patients with cancer. These patients may benefit from therapeutic modalities targeting the altered biochemistry of LMW-E or its associated vulnerabilities. Cancer Res; 78(19); 5481-91. ©2018 AACR.
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Affiliation(s)
- Joseph A Caruso
- Department of Pathology, University of California, San Francisco, San Francisco, California.
| | | | - Jason P W Carey
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Kelly K Hunt
- Department of Breast Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Khandan Keyomarsi
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
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25
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Structure of the origin recognition complex bound to DNA replication origin. Nature 2018; 559:217-222. [DOI: 10.1038/s41586-018-0293-x] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 05/08/2018] [Indexed: 11/09/2022]
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26
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Kang S, Kang MS, Ryu E, Myung K. Eukaryotic DNA replication: Orchestrated action of multi-subunit protein complexes. Mutat Res 2018; 809:58-69. [PMID: 28501329 DOI: 10.1016/j.mrfmmm.2017.04.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 04/13/2017] [Accepted: 04/30/2017] [Indexed: 06/07/2023]
Abstract
Genome duplication is an essential process to preserve genetic information between generations. The eukaryotic cell cycle is composed of functionally distinct phases: G1, S, G2, and M. One of the key replicative proteins that participate at every stage of DNA replication is the Mcm2-7 complex, a replicative helicase. In the G1 phase, inactive Mcm2-7 complexes are loaded on the replication origins by replication-initiator proteins, ORC and Cdc6. Two kinases, S-CDK and DDK, convert the inactive origin-loaded Mcm2-7 complex to an active helicase, the CMG complex in the S phase. The activated CMG complex begins DNA unwinding and recruits enzymes essential for DNA synthesis to assemble a replisome at the replication fork. After completion of DNA synthesis, the inactive CMG complex on the replicated DNA is removed from chromatin to terminate DNA replication. In this review, we will discuss the structure, function, and regulation of the molecular machines involved in each step of DNA replication.
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Affiliation(s)
- Sukhyun Kang
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea.
| | - Mi-Sun Kang
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Eunjin Ryu
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea; School of Life Sciences, Ulsan National Institute for Science and Technology, Ulsan 44919, Republic of Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea; School of Life Sciences, Ulsan National Institute for Science and Technology, Ulsan 44919, Republic of Korea
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27
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Warner MD, Azmi IF, Kang S, Zhao Y, Bell SP. Replication origin-flanking roadblocks reveal origin-licensing dynamics and altered sequence dependence. J Biol Chem 2017; 292:21417-21430. [PMID: 29074622 PMCID: PMC5766963 DOI: 10.1074/jbc.m117.815639] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/13/2017] [Indexed: 11/06/2022] Open
Abstract
In eukaryotes, DNA replication initiates from multiple origins of replication for timely genome duplication. These sites are selected by origin licensing, during which the core enzyme of the eukaryotic DNA replicative helicase, the Mcm2-7 (minichromosome maintenance) complex, is loaded at each origin. This origin licensing requires loading two Mcm2-7 helicases around origin DNA in a head-to-head orientation. Current models suggest that the origin-recognition complex (ORC) and cell-division cycle 6 (Cdc6) proteins recognize and encircle origin DNA and assemble an Mcm2-7 double-hexamer around adjacent double-stranded DNA. To test this model and assess the location of Mcm2-7 initial loading, we placed DNA-protein roadblocks at defined positions adjacent to the essential ORC-binding site within Saccharomyces cerevisiae origin DNA. Roadblocks were made either by covalent cross-linking of the HpaII methyltransferase to DNA or through binding of a transcription activator-like effector (TALE) protein. Contrary to the sites of Mcm2-7 recruitment being precisely defined, only single roadblocks that inhibited ORC-DNA binding showed helicase loading defects. We observed inhibition of helicase loading without inhibition of ORC-DNA binding only when roadblocks were placed on both sides of the origin to restrict sliding of a helicase-loading intermediate. Consistent with a sliding helicase-loading intermediate, when either one of the flanking roadblocks was eliminated, the remaining roadblock had no effect on helicase loading. Interestingly, either origin-flanking nucleosomes or roadblocks resulted in helicase loading being dependent on an additional origin sequence known to be a weaker ORC-DNA-binding site. Together, our findings support a model in which sliding helicase-loading intermediates increase the flexibility of the DNA sequence requirements for origin licensing.
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Affiliation(s)
- Megan D Warner
- From the Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 and
| | - Ishara F Azmi
- From the Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 and
| | - Sukhyun Kang
- From the Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 and
| | - Yanding Zhao
- the Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454
| | - Stephen P Bell
- From the Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 and
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28
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Riera A, Barbon M, Noguchi Y, Reuter LM, Schneider S, Speck C. From structure to mechanism-understanding initiation of DNA replication. Genes Dev 2017; 31:1073-1088. [PMID: 28717046 PMCID: PMC5538431 DOI: 10.1101/gad.298232.117] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In this Review, Riera et al. review recent structural and biochemical insights that start to explain how specific proteins recognize DNA replication origins, load the replicative helicase on DNA, unwind DNA, synthesize new DNA strands, and reassemble chromatin. DNA replication results in the doubling of the genome prior to cell division. This process requires the assembly of 50 or more protein factors into a replication fork. Here, we review recent structural and biochemical insights that start to explain how specific proteins recognize DNA replication origins, load the replicative helicase on DNA, unwind DNA, synthesize new DNA strands, and reassemble chromatin. We focus on the minichromosome maintenance (MCM2–7) proteins, which form the core of the eukaryotic replication fork, as this complex undergoes major structural rearrangements in order to engage with DNA, regulate its DNA-unwinding activity, and maintain genome stability.
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Affiliation(s)
- Alberto Riera
- DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Marta Barbon
- DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom.,Medical Research Council (MRC) London Institute of Medical Sciences (LMS), London W12 0NN, United Kingdom
| | - Yasunori Noguchi
- DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - L Maximilian Reuter
- DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Sarah Schneider
- DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Christian Speck
- DNA Replication Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom.,Medical Research Council (MRC) London Institute of Medical Sciences (LMS), London W12 0NN, United Kingdom
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29
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Abstract
The accurate and complete replication of genomic DNA is essential for all life. In eukaryotic cells, the assembly of the multi-enzyme replisomes that perform replication is divided into stages that occur at distinct phases of the cell cycle. Replicative DNA helicases are loaded around origins of DNA replication exclusively during G1 phase. The loaded helicases are then activated during S phase and associate with the replicative DNA polymerases and other accessory proteins. The function of the resulting replisomes is monitored by checkpoint proteins that protect arrested replisomes and inhibit new initiation when replication is inhibited. The replisome also coordinates nucleosome disassembly, assembly, and the establishment of sister chromatid cohesion. Finally, when two replisomes converge they are disassembled. Studies in Saccharomyces cerevisiae have led the way in our understanding of these processes. Here, we review our increasingly molecular understanding of these events and their regulation.
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30
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Ravoitytė B, Wellinger RE. Non-Canonical Replication Initiation: You're Fired! Genes (Basel) 2017; 8:genes8020054. [PMID: 28134821 PMCID: PMC5333043 DOI: 10.3390/genes8020054] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 01/19/2017] [Indexed: 12/25/2022] Open
Abstract
The division of prokaryotic and eukaryotic cells produces two cells that inherit a perfect copy of the genetic material originally derived from the mother cell. The initiation of canonical DNA replication must be coordinated to the cell cycle to ensure the accuracy of genome duplication. Controlled replication initiation depends on a complex interplay of cis-acting DNA sequences, the so-called origins of replication (ori), with trans-acting factors involved in the onset of DNA synthesis. The interplay of cis-acting elements and trans-acting factors ensures that cells initiate replication at sequence-specific sites only once, and in a timely order, to avoid chromosomal endoreplication. However, chromosome breakage and excessive RNA:DNA hybrid formation can cause break-induced (BIR) or transcription-initiated replication (TIR), respectively. These non-canonical replication events are expected to affect eukaryotic genome function and maintenance, and could be important for genome evolution and disease development. In this review, we describe the difference between canonical and non-canonical DNA replication, and focus on mechanistic differences and common features between BIR and TIR. Finally, we discuss open issues on the factors and molecular mechanisms involved in TIR.
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Affiliation(s)
- Bazilė Ravoitytė
- Nature Research Centre, Akademijos g. 2, LT-08412 Vilnius, Lithuania.
| | - Ralf Erik Wellinger
- CABIMER-Universidad de Sevilla, Avd Americo Vespucio sn, 41092 Sevilla, Spain.
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31
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Parker MW, Botchan MR, Berger JM. Mechanisms and regulation of DNA replication initiation in eukaryotes. Crit Rev Biochem Mol Biol 2017; 52:107-144. [PMID: 28094588 DOI: 10.1080/10409238.2016.1274717] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cellular DNA replication is initiated through the action of multiprotein complexes that recognize replication start sites in the chromosome (termed origins) and facilitate duplex DNA melting within these regions. In a typical cell cycle, initiation occurs only once per origin and each round of replication is tightly coupled to cell division. To avoid aberrant origin firing and re-replication, eukaryotes tightly regulate two events in the initiation process: loading of the replicative helicase, MCM2-7, onto chromatin by the origin recognition complex (ORC), and subsequent activation of the helicase by its incorporation into a complex known as the CMG. Recent work has begun to reveal the details of an orchestrated and sequential exchange of initiation factors on DNA that give rise to a replication-competent complex, the replisome. Here, we review the molecular mechanisms that underpin eukaryotic DNA replication initiation - from selecting replication start sites to replicative helicase loading and activation - and describe how these events are often distinctly regulated across different eukaryotic model organisms.
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Affiliation(s)
- Matthew W Parker
- a Department of Biophysics and Biophysical Chemistry , Johns Hopkins University School of Medicine , Baltimore , MD , USA
| | - Michael R Botchan
- b Department of Molecular and Cell Biology , University of California Berkeley , Berkeley , CA , USA
| | - James M Berger
- a Department of Biophysics and Biophysical Chemistry , Johns Hopkins University School of Medicine , Baltimore , MD , USA
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32
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Singh VK, Krishnamachari A. Context based computational analysis and characterization of ARS consensus sequences (ACS) of Saccharomyces cerevisiae genome. GENOMICS DATA 2016; 9:130-6. [PMID: 27508123 PMCID: PMC4971157 DOI: 10.1016/j.gdata.2016.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 06/27/2016] [Accepted: 07/06/2016] [Indexed: 01/08/2023]
Abstract
Genome-wide experimental studies in Saccharomyces cerevisiae reveal that autonomous replicating sequence (ARS) requires an essential consensus sequence (ACS) for replication activity. Computational studies identified thousands of ACS like patterns in the genome. However, only a few hundreds of these sites act as replicating sites and the rest are considered as dormant or evolving sites. In a bid to understand the sequence makeup of replication sites, a content and context-based analysis was performed on a set of replicating ACS sequences that binds to origin-recognition complex (ORC) denoted as ORC-ACS and non-replicating ACS sequences (nrACS), that are not bound by ORC. In this study, DNA properties such as base composition, correlation, sequence dependent thermodynamic and DNA structural profiles, and their positions have been considered for characterizing ORC-ACS and nrACS. Analysis reveals that ORC-ACS depict marked differences in nucleotide composition and context features in its vicinity compared to nrACS. Interestingly, an A-rich motif was also discovered in ORC-ACS sequences within its nucleosome-free region. Profound changes in the conformational features, such as DNA helical twist, inclination angle and stacking energy between ORC-ACS and nrACS were observed. Distribution of ACS motifs in the non-coding segments points to the locations of ORC-ACS which are found far away from the adjacent gene start position compared to nrACS thereby enabling an accessible environment for ORC-proteins. Our attempt is novel in considering the contextual view of ACS and its flanking region along with nucleosome positioning in the S. cerevisiae genome and may be useful for any computational prediction scheme.
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33
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High Throughput Analyses of Budding Yeast ARSs Reveal New DNA Elements Capable of Conferring Centromere-Independent Plasmid Propagation. G3-GENES GENOMES GENETICS 2016; 6:993-1012. [PMID: 26865697 PMCID: PMC4825667 DOI: 10.1534/g3.116.027904] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The ability of plasmids to propagate in Saccharomyces cerevisiae has been instrumental in defining eukaryotic chromosomal control elements. Stable propagation demands both plasmid replication, which requires a chromosomal replication origin (i.e., an ARS), and plasmid distribution to dividing cells, which requires either a chromosomal centromere for segregation or a plasmid-partitioning element. While our knowledge of yeast ARSs and centromeres is relatively advanced, we know less about chromosomal regions that can function as plasmid partitioning elements. The Rap1 protein-binding site (RAP1) present in transcriptional silencers and telomeres of budding yeast is a known plasmid-partitioning element that functions to anchor a plasmid to the inner nuclear membrane (INM), which in turn facilitates plasmid distribution to daughter cells. This Rap1-dependent INM-anchoring also has an important chromosomal role in higher-order chromosomal structures that enhance transcriptional silencing and telomere stability. Thus, plasmid partitioning can reflect fundamental features of chromosome structure and biology, yet a systematic screen for plasmid partitioning elements has not been reported. Here, we couple deep sequencing with competitive growth experiments of a plasmid library containing thousands of short ARS fragments to identify new plasmid partitioning elements. Competitive growth experiments were performed with libraries that differed only in terms of the presence or absence of a centromere. Comparisons of the behavior of ARS fragments in the two experiments allowed us to identify sequences that were likely to drive plasmid partitioning. In addition to the silencer RAP1 site, we identified 74 new putative plasmid-partitioning motifs predicted to act as binding sites for DNA binding proteins enriched for roles in negative regulation of gene expression and G2/M-phase associated biology. These data expand our knowledge of chromosomal elements that may function in plasmid partitioning and suggest underlying biological roles shared by such elements.
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34
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Duzdevich D, Warner MD, Ticau S, Ivica NA, Bell SP, Greene EC. The dynamics of eukaryotic replication initiation: origin specificity, licensing, and firing at the single-molecule level. Mol Cell 2015; 58:483-94. [PMID: 25921072 DOI: 10.1016/j.molcel.2015.03.017] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 01/20/2015] [Accepted: 03/11/2015] [Indexed: 12/23/2022]
Abstract
Eukaryotic replication initiation is highly regulated and dynamic. It begins with the origin recognition complex (ORC) binding DNA sites called origins of replication. ORC, together with Cdc6 and Cdt1, mediate pre-replicative complex (pre-RC) assembly by loading a double hexamer of Mcm2-7: the core of the replicative helicase. Here, we use single-molecule imaging to directly visualize Saccharomyces cerevisiae pre-RC assembly and replisome firing in real time. We show that ORC can locate and stably bind origins within large tracts of non-origin DNA and that Cdc6 drives ordered pre-RC assembly. We further show that the dynamics of the ORC-Cdc6 interaction dictate Mcm2-7 loading specificity and that Mcm2-7 double hexamers form preferentially at a native origin sequence. Finally, we demonstrate that single Mcm2-7 hexamers propagate bidirectionally, monotonically, and processively as constituents of active replisomes.
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Affiliation(s)
- Daniel Duzdevich
- Department of Biological Sciences, Columbia University, New York, NY 10032, USA
| | - Megan D Warner
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Simina Ticau
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Nikola A Ivica
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Stephen P Bell
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Eric C Greene
- Department of Biochemistry and Molecular Biophysics, and the Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA.
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35
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Peng C, Luo H, Zhang X, Gao F. Recent advances in the genome-wide study of DNA replication origins in yeast. Front Microbiol 2015; 6:117. [PMID: 25745419 PMCID: PMC4333867 DOI: 10.3389/fmicb.2015.00117] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 01/29/2015] [Indexed: 11/13/2022] Open
Abstract
DNA replication, one of the central events in the cell cycle, is the basis of biological inheritance. In order to be duplicated, a DNA double helix must be opened at defined sites, which are called DNA replication origins (ORIs). Unlike in bacteria, where replication initiates from a single replication origin, multiple origins are utilized in the eukaryotic genomes. Among them, the ORIs in budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe have been best characterized. In recent years, advances in DNA microarray and next-generation sequencing technologies have increased the number of yeast species involved in ORIs research dramatically. The ORIs in some non-conventional yeast species such as Kluyveromyces lactis and Pichia pastoris have also been genome-widely identified. Relevant databases of replication origins in yeast were constructed, then the comparative genomic analysis can be carried out. Here, we review several experimental approaches that have been used to map replication origins in yeast and some of the available web resources related to yeast ORIs. We also discuss the sequence characteristics and chromosome structures of ORIs in the four yeast species, which can be utilized to improve yeast replication origins prediction.
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Affiliation(s)
- Chong Peng
- Department of Physics, Tianjin University , Tianjin, China
| | - Hao Luo
- Department of Physics, Tianjin University , Tianjin, China
| | - Xi Zhang
- Department of Physics, Tianjin University , Tianjin, China
| | - Feng Gao
- Department of Physics, 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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36
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Powell SK, MacAlpine HK, Prinz JA, Li Y, Belsky JA, MacAlpine DM. Dynamic loading and redistribution of the Mcm2-7 helicase complex through the cell cycle. EMBO J 2015; 34:531-43. [PMID: 25555795 DOI: 10.15252/embj.201488307] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Eukaryotic replication origins are defined by the ORC-dependent loading of the Mcm2-7 helicase complex onto chromatin in G1. Paradoxically, there is a vast excess of Mcm2-7 relative to ORC assembled onto chromatin in G1. These excess Mcm2-7 complexes exhibit little co-localization with ORC or replication foci and can function as dormant origins. We dissected the mechanisms regulating the assembly and distribution of the Mcm2-7 complex in the Drosophila genome. We found that in the absence of cyclin E/Cdk2 activity, there was a 10-fold decrease in chromatin-associated Mcm2-7 relative to the levels found at the G1/S transition. The minimal amounts of Mcm2-7 loaded in the absence of cyclin E/Cdk2 activity were strictly localized to ORC binding sites. In contrast, cyclin E/Cdk2 activity was required for maximal loading of Mcm2-7 and a dramatic genome-wide reorganization of the distribution of Mcm2-7 that is shaped by active transcription. Thus, increasing cyclin E/Cdk2 activity over the course of G1 is not only critical for Mcm2-7 loading, but also for the distribution of the Mcm2-7 helicase prior to S-phase entry.
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Affiliation(s)
- Sara K Powell
- Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Heather K MacAlpine
- Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Joseph A Prinz
- Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Yulong Li
- Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Jason A Belsky
- Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - David M MacAlpine
- Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
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37
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Origin replication complex binding, nucleosome depletion patterns, and a primary sequence motif can predict origins of replication in a genome with epigenetic centromeres. mBio 2014; 5:e01703-14. [PMID: 25182328 PMCID: PMC4173791 DOI: 10.1128/mbio.01703-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Origins of DNA replication are key genetic elements, yet their identification remains elusive in most organisms. In previous work, we found that centromeres contain origins of replication (ORIs) that are determined epigenetically in the pathogenic yeast Candida albicans. In this study, we used origin recognition complex (ORC) binding and nucleosome occupancy patterns in Saccharomyces cerevisiae and Kluyveromyces lactis to train a machine learning algorithm to predict the position of active arm (noncentromeric) origins in the C. albicans genome. The model identified bona fide active origins as determined by the presence of replication intermediates on nondenaturing two-dimensional (2D) gels. Importantly, these origins function at their native chromosomal loci and also as autonomously replicating sequences (ARSs) on a linear plasmid. A “mini-ARS screen” identified at least one and often two ARS regions of ≥100 bp within each bona fide origin. Furthermore, a 15-bp AC-rich consensus motif was associated with the predicted origins and conferred autonomous replicating activity to the mini-ARSs. Thus, while centromeres and the origins associated with them are epigenetic, arm origins are dependent upon critical DNA features, such as a binding site for ORC and a propensity for nucleosome exclusion. DNA replication machinery is highly conserved, yet the definition of exactly what specifies a replication origin differs in different species. Here, we utilized computational genomics to predict origin locations in Candida albicans by combining locations of binding sites for the conserved origin replication complex, necessary for replication initiation, together with chromatin organization patterns. We identified predicted sequences that exhibited bona fide origin function and developed a linear plasmid assay to delimit the DNA fragments necessary for origin function. Additionally, we found that a short AC-rich motif, which is enriched in predicted origins, is required for origin function. Thus, we demonstrated a new machine learning paradigm for identification of potential origins from a genome with no prior information. Furthermore, this work suggests that C. albicans has two different types of origins: “hard-wired” arm origins that rely upon specific sequence motifs and “epigenetic” centromeric origins that are recruited to kinetochores in a sequence-independent manner.
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38
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On KF, Beuron F, Frith D, Snijders AP, Morris EP, Diffley JFX. Prereplicative complexes assembled in vitro support origin-dependent and independent DNA replication. EMBO J 2014; 33:605-20. [PMID: 24566989 PMCID: PMC3989654 DOI: 10.1002/embj.201387369] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 12/17/2013] [Accepted: 01/10/2014] [Indexed: 11/09/2022] Open
Abstract
Eukaryotic DNA replication initiates from multiple replication origins. To ensure each origin fires just once per cell cycle, initiation is divided into two biochemically discrete steps: the Mcm2-7 helicase is first loaded into prereplicative complexes (pre-RCs) as an inactive double hexamer by the origin recognition complex (ORC), Cdt1 and Cdc6; the helicase is then activated by a set of "firing factors." Here, we show that plasmids containing pre-RCs assembled with purified proteins support complete and semi-conservative replication in extracts from budding yeast cells overexpressing firing factors. Replication requires cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK). DDK phosphorylation of Mcm2-7 does not by itself promote separation of the double hexamer, but is required for the recruitment of firing factors and replisome components in the extract. Plasmid replication does not require a functional replication origin; however, in the presence of competitor DNA and limiting ORC concentrations, replication becomes origin-dependent in this system. These experiments indicate that Mcm2-7 double hexamers can be precursors of replication and provide insight into the nature of eukaryotic DNA replication origins.
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Affiliation(s)
- Kin Fan On
- Chromosome Replication Laboratory, Cancer Research UK London Research InstituteSouth Mimms, Herts, UK
| | - Fabienne Beuron
- Division of Structural Biology, The Institute of Cancer ResearchLondon, UK
| | - David Frith
- Protein Analysis and Proteomics, Cancer Research UK London Research Institute, Clare Hall LaboratoriesSouth Mimms, Herts, UK
| | - Ambrosius P Snijders
- Protein Analysis and Proteomics, Cancer Research UK London Research Institute, Clare Hall LaboratoriesSouth Mimms, Herts, UK
| | - Edward P Morris
- Division of Structural Biology, The Institute of Cancer ResearchLondon, UK
| | - John F X Diffley
- Chromosome Replication Laboratory, Cancer Research UK London Research InstituteSouth Mimms, Herts, UK
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39
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Gros J, Devbhandari S, Remus D. Origin plasticity during budding yeast DNA replication in vitro. EMBO J 2014; 33:621-36. [PMID: 24566988 DOI: 10.1002/embj.201387278] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The separation of DNA replication origin licensing and activation in the cell cycle is essential for genome stability across generations in eukaryotic cells. Pre-replicative complexes (pre-RCs) license origins by loading Mcm2-7 complexes in inactive form around DNA. During origin firing in S phase, replisomes assemble around the activated Mcm2-7 DNA helicase. Budding yeast pre-RCs have previously been reconstituted in vitro with purified proteins. Here, we show that reconstituted pre-RCs support replication of plasmid DNA in yeast cell extracts in a reaction that exhibits hallmarks of cellular replication initiation. Plasmid replication in vitro results in the generation of covalently closed circular daughter molecules, indicating that the system recapitulates the initiation, elongation, and termination stages of DNA replication. Unexpectedly, yeast origin DNA is not strictly required for DNA replication in vitro, as heterologous DNA sequences could support replication of plasmid molecules. Our findings support the notion that epigenetic mechanisms are important for determining replication origin sites in budding yeast, highlighting mechanistic principles of replication origin specification that are common among eukaryotes.
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Affiliation(s)
- Julien Gros
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
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40
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Abstract
The onset of genomic DNA synthesis requires precise interactions of specialized initiator proteins with DNA at sites where the replication machinery can be loaded. These sites, defined as replication origins, are found at a few unique locations in all of the prokaryotic chromosomes examined so far. However, replication origins are dispersed among tens of thousands of loci in metazoan chromosomes, thereby raising questions regarding the role of specific nucleotide sequences and chromatin environment in origin selection and the mechanisms used by initiators to recognize replication origins. Close examination of bacterial and archaeal replication origins reveals an array of DNA sequence motifs that position individual initiator protein molecules and promote initiator oligomerization on origin DNA. Conversely, the need for specific recognition sequences in eukaryotic replication origins is relaxed. In fact, the primary rule for origin selection appears to be flexibility, a feature that is modulated either by structural elements or by epigenetic mechanisms at least partly linked to the organization of the genome for gene expression.
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Affiliation(s)
- Alan C Leonard
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, Florida 32901
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41
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Hoshina S, Yura K, Teranishi H, Kiyasu N, Tominaga A, Kadoma H, Nakatsuka A, Kunichika T, Obuse C, Waga S. Human origin recognition complex binds preferentially to G-quadruplex-preferable RNA and single-stranded DNA. J Biol Chem 2013; 288:30161-30171. [PMID: 24003239 DOI: 10.1074/jbc.m113.492504] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Origin recognition complex (ORC), consisting of six subunits ORC1-6, is known to bind to replication origins and function in the initiation of DNA replication in eukaryotic cells. In contrast to the fact that Saccharomyces cerevisiae ORC recognizes the replication origin in a sequence-specific manner, metazoan ORC has not exhibited strict sequence-specificity for DNA binding. Here we report that human ORC binds preferentially to G-quadruplex (G4)-preferable G-rich RNA or single-stranded DNA (ssDNA). We mapped the G-rich RNA-binding domain in the ORC1 subunit, in a region adjacent to its ATPase domain. This domain itself has an ability to preferentially recognize G4-preferable sequences of ssDNA. Furthermore, we found, by structure modeling, that the G-rich RNA-binding domain is similar to the N-terminal portion of AdoMet_MTase domain of mammalian DNA methyltransferase 1. Therefore, in contrast with the binding to double-stranded DNA, human ORC has an apparent sequence preference with respect to its RNA/ssDNA binding. Interestingly, this specificity coincides with the common signature present in most of the human replication origins. We expect that our findings provide new insights into the regulations of function and chromatin binding of metazoan ORCs.
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Affiliation(s)
- Shoko Hoshina
- From the Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Tokyo 112-8681, Japan
| | - Kei Yura
- the Graduate School of Humanities and Sciences, Ochanomizu University, Tokyo 112-8610, Japan
| | - Honami Teranishi
- From the Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Tokyo 112-8681, Japan
| | - Noriko Kiyasu
- From the Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Tokyo 112-8681, Japan
| | - Ayumi Tominaga
- From the Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Tokyo 112-8681, Japan
| | - Haruka Kadoma
- From the Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Tokyo 112-8681, Japan
| | - Ayaka Nakatsuka
- From the Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Tokyo 112-8681, Japan
| | - Tomoko Kunichika
- the Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan, and
| | - Chikashi Obuse
- the Division of Molecular Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 001-0021, Japan
| | - Shou Waga
- From the Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Tokyo 112-8681, Japan,.
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42
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Liu R, Hu J. DNABind: A hybrid algorithm for structure-based prediction of DNA-binding residues by combining machine learning- and template-based approaches. Proteins 2013; 81:1885-99. [DOI: 10.1002/prot.24330] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 05/02/2013] [Accepted: 05/12/2013] [Indexed: 01/10/2023]
Affiliation(s)
- Rong Liu
- Department of Computer Science and Engineering; University of South Carolina; Columbia South Carolina 29208
- Center for Bioinformatics; College of Life Science and Technology; Huazhong Agricultural University; Wuhan 430070 People's Republic of China
| | - Jianjun Hu
- Department of Computer Science and Engineering; University of South Carolina; Columbia South Carolina 29208
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43
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Hizume K, Yagura M, Araki H. Concerted interaction between origin recognition complex (ORC), nucleosomes and replication origin DNA ensures stable ORC-origin binding. Genes Cells 2013; 18:764-79. [DOI: 10.1111/gtc.12073] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 05/14/2013] [Indexed: 01/21/2023]
Affiliation(s)
| | - Masaru Yagura
- Division of Microbial Genetics; National Institute of Genetics; Mishima; 411-8540; Japan
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44
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Lõoke M, Kristjuhan K, Värv S, Kristjuhan A. Chromatin-dependent and -independent regulation of DNA replication origin activation in budding yeast. EMBO Rep 2012; 14:191-8. [PMID: 23222539 PMCID: PMC3596130 DOI: 10.1038/embor.2012.196] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 11/13/2012] [Accepted: 11/13/2012] [Indexed: 11/09/2022] Open
Abstract
To elucidate the role of the chromatin environment in the regulation of replication origin activation, autonomously replicating sequences were inserted into identical locations in the budding yeast genome and their activation times in S phase determined. Chromatin-dependent origins adopt to the firing time of the surrounding locus. In contrast, the origins containing two binding sites for Forkhead transcription factors are activated early in the S phase regardless of their location in the genome. Our results also show that genuinely late-replicating parts of the genome can be converted into early-replicating loci by insertion of a chromatin-independent early replication origin, ARS607, whereas insertion of two Forkhead-binding sites is not sufficient for conversion.
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Affiliation(s)
- Marko Lõoke
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, Tartu 51010, Estonia
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Chisamore-Robert P, Peeters S, Shostak K, Yankulov K. Directional telomeric silencing and lack of canonical B1 elements in two silencer Autonomously Replicating Sequences in S. cerevisiae. BMC Mol Biol 2012; 13:34. [PMID: 23157664 PMCID: PMC3545912 DOI: 10.1186/1471-2199-13-34] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 11/15/2012] [Indexed: 12/29/2022] Open
Abstract
Background Autonomously Replicating Sequences (ARS) in S. cerevisiae serve as origins of DNA replication or as components of cis-acting silencers, which impose positional repression at the mating type loci and at the telomeres. Both types of ARS can act as replicators or silencers, however it is not clear how these quite diverse functions are executed. It is believed that all ARS contain a core module of an essential ARS Consensus Sequence (ACS) and a non-essential B1 element. Results We have tested how the B1 elements contribute to the silencer and replicator function of ARS. We report that the ACS-B1 orientation of ARS has a profound effect on the levels of gene silencing at telomeres. We also report that the destruction of the canonical B1 elements in two silencer ARS (ARS317 and ARS319) has no effect on their silencer and replicator activity. Conclusions The observed orientation effects on gene silencing suggest that ARSs can act as both proto-silencers and as insulator elements. In addition, the lack of B1 suggests that the ACS-B1 module could be different in silencer and replicator ARS.
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Gidvani RD, Sudmant P, Li G, DaSilva LF, McConkey BJ, Duncker BP, Ingalls BP. A quantitative model of the initiation of DNA replication in Saccharomyces cerevisiae predicts the effects of system perturbations. BMC SYSTEMS BIOLOGY 2012; 6:78. [PMID: 22738223 PMCID: PMC3439281 DOI: 10.1186/1752-0509-6-78] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 06/05/2012] [Indexed: 11/17/2022]
Abstract
Background Eukaryotic cell proliferation involves DNA replication, a tightly regulated process mediated by a multitude of protein factors. In budding yeast, the initiation of replication is facilitated by the heterohexameric origin recognition complex (ORC). ORC binds to specific origins of replication and then serves as a scaffold for the recruitment of other factors such as Cdt1, Cdc6, the Mcm2-7 complex, Cdc45 and the Dbf4-Cdc7 kinase complex. While many of the mechanisms controlling these associations are well documented, mathematical models are needed to explore the network’s dynamic behaviour. We have developed an ordinary differential equation-based model of the protein-protein interaction network describing replication initiation. Results The model was validated against quantified levels of protein factors over a range of cell cycle timepoints. Using chromatin extracts from synchronized Saccharomyces cerevisiae cell cultures, we were able to monitor the in vivo fluctuations of several of the aforementioned proteins, with additional data obtained from the literature. The model behaviour conforms to perturbation trials previously reported in the literature, and accurately predicts the results of our own knockdown experiments. Furthermore, we successfully incorporated our replication initiation model into an established model of the entire yeast cell cycle, thus providing a comprehensive description of these processes. Conclusions This study establishes a robust model of the processes driving DNA replication initiation. The model was validated against observed cell concentrations of the driving factors, and characterizes the interactions between factors implicated in eukaryotic DNA replication. Finally, this model can serve as a guide in efforts to generate a comprehensive model of the mammalian cell cycle in order to explore cancer-related phenotypes.
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Affiliation(s)
- Rohan D Gidvani
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
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Di Rienzi SC, Lindstrom KC, Mann T, Noble WS, Raghuraman MK, Brewer BJ. Maintaining replication origins in the face of genomic change. Genome Res 2012; 22:1940-52. [PMID: 22665441 PMCID: PMC3460189 DOI: 10.1101/gr.138248.112] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Origins of replication present a paradox to evolutionary biologists. As a collection, they are absolutely essential genomic features, but individually are highly redundant and nonessential. It is therefore difficult to predict to what extent and in what regard origins are conserved over evolutionary time. Here, through a comparative genomic analysis of replication origins and chromosomal replication patterns in the budding yeasts Saccharomyces cerevisiae and Lachancea waltii, we assess to what extent replication origins survived genomic change produced from 150 million years of evolution. We find that L. waltii origins exhibit a core consensus sequence and nucleosome occupancy pattern highly similar to those of S. cerevisiae origins. We further observe that the overall progression of chromosomal replication is similar between L. waltii and S. cerevisiae. Nevertheless, few origins show evidence of being conserved in location between the two species. Among the conserved origins are those surrounding centromeres and adjacent to histone genes, suggesting that proximity to an origin may be important for their regulation. We conclude that, over evolutionary time, origins maintain sequence, structure, and regulation, but are continually being created and destroyed, with the result that their locations are generally not conserved.
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Affiliation(s)
- Sara C Di Rienzi
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
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Moriyama K, Yoshizawa-Sugata N, Obuse C, Tsurimoto T, Masai H. Epstein-Barr nuclear antigen 1 (EBNA1)-dependent recruitment of origin recognition complex (Orc) on oriP of Epstein-Barr virus with purified proteins: stimulation by Cdc6 through its direct interaction with EBNA1. J Biol Chem 2012; 287:23977-94. [PMID: 22589552 DOI: 10.1074/jbc.m112.368456] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Origin recognition complex (Orc) plays an essential role in directing assembly of prereplicative complex at selective sites on chromosomes. However, Orc from vertebrates is reported to bind to DNA in a sequence-nonspecific manner, and it is still unclear how it selects specific genomic loci and how Cdc6, another conserved AAA(+) factor known to interact with Orc, participates in this process. Replication from oriP, the latent origin of Epstein-Barr virus, provides an excellent model system for the study of initiation on the host chromosomes because it is known to depend on prereplicative complex factors, including Orc and Mcm. Here, we show that Orc is recruited selectively at the essential dyad symmetry element in nuclear extracts in a manner dependent on EBNA1, which specifically binds to dyad symmetry. With purified proteins, EBNA1 can recruit both Cdc6 and Orc independently on a DNA containing EBNA1 binding sites, and Cdc6 facilitates the Orc recruitment by EBNA1. Purified Cdc6 directly binds to EBNA1, whereas association of Orc with EBNA1 requires the presence of the oriP DNA. Nuclease protection assays suggest that Orc associates with DNA segments on both sides adjacent to the EBNA1 binding sites and that this process is stimulated by the presence of Cdc6. Thus, EBNA1 can direct localized assembly of Orc in a process that is facilitated by Cdc6. The possibility of similar modes of recruitment of Orc/Cdc6 at the human chromosomal origins will be discussed.
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Affiliation(s)
- Kenji Moriyama
- Genome Dynamics Project, Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
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Structure, replication efficiency and fragility of yeast ARS elements. Res Microbiol 2012; 163:243-53. [DOI: 10.1016/j.resmic.2012.03.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 01/21/2012] [Indexed: 11/16/2022]
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Chen W, Feng P, Lin H. Prediction of replication origins by calculating DNA structural properties. FEBS Lett 2012; 586:934-8. [PMID: 22449982 DOI: 10.1016/j.febslet.2012.02.034] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 02/21/2012] [Accepted: 02/21/2012] [Indexed: 11/17/2022]
Abstract
In this study, we introduced two DNA structural characteristics, namely, bendability and hydroxyl radical cleavage intensity to analyze origin of replication (ORI) in the Saccharomyces cerevisiae genome. We found that both DNA bendability and cleavage intensity in core replication regions were significantly lower than in the linker regions. By using these two DNA structural characteristics, we developed a computational model for ORI prediction and evaluated the model in a benchmark dataset. The predictive performance of the jackknife cross-validation indicates that DNA bendability and cleavage intensity have the ability to describe core replication regions and our model is effective in ORI prediction.
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Affiliation(s)
- Wei Chen
- Department of Physics, School of Sciences, Hebei United University, Tangshan, China.
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