1
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Karagyozova T, Almouzni G. Replicating chromatin in the nucleus: A histone variant perspective. Curr Opin Cell Biol 2024; 89:102397. [PMID: 38981199 DOI: 10.1016/j.ceb.2024.102397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 06/07/2024] [Accepted: 06/17/2024] [Indexed: 07/11/2024]
Abstract
In eukaryotes, chromatin and DNA replication are intimately linked, whereby chromatin impacts DNA replication control while genome duplication involves recovery of chromatin organisation. Here, we review recent advances in this area using a histone variant lens. We highlight how nucleosomal features interplay with origin definition and how the order of origin firing links with chromatin states in early mammalian development. We next discuss histone recycling and de novo deposition at the fork to finally open on the post-replicative recovery of the chromatin landscape to promote maintenance of cell identity.
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Affiliation(s)
- Tina Karagyozova
- Institut Curie, PSL Research University, CNRS, Sorbonne Université, Nuclear Dynamics Unit, Equipe Labellisée Ligue Contre le Cancer, 26 rue d'Ulm, 75005 Paris, France
| | - Geneviève Almouzni
- Institut Curie, PSL Research University, CNRS, Sorbonne Université, Nuclear Dynamics Unit, Equipe Labellisée Ligue Contre le Cancer, 26 rue d'Ulm, 75005 Paris, France.
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2
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Chua GNL, Liu S. When Force Met Fluorescence: Single-Molecule Manipulation and Visualization of Protein-DNA Interactions. Annu Rev Biophys 2024; 53:169-191. [PMID: 38237015 DOI: 10.1146/annurev-biophys-030822-032904] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Myriad DNA-binding proteins undergo dynamic assembly, translocation, and conformational changes while on DNA or alter the physical configuration of the DNA substrate to control its metabolism. It is now possible to directly observe these activities-often central to the protein function-thanks to the advent of single-molecule fluorescence- and force-based techniques. In particular, the integration of fluorescence detection and force manipulation has unlocked multidimensional measurements of protein-DNA interactions and yielded unprecedented mechanistic insights into the biomolecular processes that orchestrate cellular life. In this review, we first introduce the different experimental geometries developed for single-molecule correlative force and fluorescence microscopy, with a focus on optical tweezers as the manipulation technique. We then describe the utility of these integrative platforms for imaging protein dynamics on DNA and chromatin, as well as their unique capabilities in generating complex DNA configurations and uncovering force-dependent protein behaviors. Finally, we give a perspective on the future directions of this emerging research field.
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Affiliation(s)
- Gabriella N L Chua
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, New York, USA;
- Tri-Institutional PhD Program in Chemical Biology, New York, New York, USA
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, New York, USA;
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3
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Ahmad H, Chetlangia N, Prasanth SG. Chromatin's Influence on Pre-Replication Complex Assembly and Function. BIOLOGY 2024; 13:152. [PMID: 38534422 DOI: 10.3390/biology13030152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/19/2024] [Accepted: 02/19/2024] [Indexed: 03/28/2024]
Abstract
In all eukaryotes, the initiation of DNA replication requires a stepwise assembly of factors onto the origins of DNA replication. This is pioneered by the Origin Recognition Complex, which recruits Cdc6. Together, they bring Cdt1, which shepherds MCM2-7 to form the OCCM complex. Sequentially, a second Cdt1-bound hexamer of MCM2-7 is recruited by ORC-Cdc6 to form an MCM double hexamer, which forms a part of the pre-RC. Although the mechanism of ORC binding to DNA varies across eukaryotes, how ORC is recruited to replication origins in human cells remains an area of intense investigation. This review discusses how the chromatin environment influences pre-RC assembly, function, and, eventually, origin activity.
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Affiliation(s)
- Hina Ahmad
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801, USA
| | - Neha Chetlangia
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801, USA
| | - Supriya G Prasanth
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801, USA
- Cancer Center at Illinois, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
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4
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Fenstermaker TK, Petruk S, Mazo A. An emerging paradigm in epigenetic marking: coordination of transcription and replication. Transcription 2024; 15:22-37. [PMID: 38378467 DOI: 10.1080/21541264.2024.2316965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/06/2024] [Indexed: 02/22/2024] Open
Abstract
DNA replication and RNA transcription both utilize DNA as a template and therefore need to coordinate their activities. The predominant theory in the field is that in order for the replication fork to proceed, transcription machinery has to be evicted from DNA until replication is complete. If that does not occur, these machineries collide, and these collisions elicit various repair mechanisms which require displacement of one of the enzymes, often RNA polymerase, in order for replication to proceed. This model is also at the heart of the epigenetic bookmarking theory, which implies that displacement of RNA polymerase during replication requires gradual re-building of chromatin structure, which guides recruitment of transcriptional proteins and resumption of transcription. We discuss these theories but also bring to light newer data that suggest that these two processes may not be as detrimental to one another as previously thought. This includes findings suggesting that these processes can occur without fork collapse and that RNA polymerase may only be transiently displaced during DNA replication. We discuss potential mechanisms by which RNA polymerase may be retained at the replication fork and quickly rebind to DNA post-replication. These discoveries are important, not only as new evidence as to how these two processes are able to occur harmoniously but also because they have implications on how transcriptional programs are maintained through DNA replication. To this end, we also discuss the coordination of replication and transcription in light of revising the current epigenetic bookmarking theory of how the active gene status can be transmitted through S phase.
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Affiliation(s)
- Tyler K Fenstermaker
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Svetlana Petruk
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Alexander Mazo
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
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5
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Chanou A, Weiβ M, Holler K, Sajid A, Straub T, Krietsch J, Sanchi A, Ummethum H, Lee CSK, Kruse E, Trauner M, Werner M, Lalonde M, Lopes M, Scialdone A, Hamperl S. Single molecule MATAC-seq reveals key determinants of DNA replication origin efficiency. Nucleic Acids Res 2023; 51:12303-12324. [PMID: 37956271 PMCID: PMC10711542 DOI: 10.1093/nar/gkad1022] [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: 11/25/2022] [Revised: 10/12/2023] [Accepted: 10/20/2023] [Indexed: 11/15/2023] Open
Abstract
Stochastic origin activation gives rise to significant cell-to-cell variability in the pattern of genome replication. The molecular basis for heterogeneity in efficiency and timing of individual origins is a long-standing question. Here, we developed Methylation Accessibility of TArgeted Chromatin domain Sequencing (MATAC-Seq) to determine single-molecule chromatin accessibility of four specific genomic loci. MATAC-Seq relies on preferential modification of accessible DNA by methyltransferases combined with Nanopore-Sequencing for direct readout of methylated DNA-bases. Applying MATAC-Seq to selected early-efficient and late-inefficient yeast replication origins revealed large heterogeneity of chromatin states. Disruption of INO80 or ISW2 chromatin remodeling complexes leads to changes at individual nucleosomal positions that correlate with changes in their replication efficiency. We found a chromatin state with an accessible nucleosome-free region in combination with well-positioned +1 and +2 nucleosomes as a strong predictor for efficient origin activation. Thus, MATAC-Seq identifies the large spectrum of alternative chromatin states that co-exist on a given locus previously masked in population-based experiments and provides a mechanistic basis for origin activation heterogeneity during eukaryotic DNA replication. Consequently, our single-molecule chromatin accessibility assay will be ideal to define single-molecule heterogeneity across many fundamental biological processes such as transcription, replication, or DNA repair in vitro and ex vivo.
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Affiliation(s)
- Anna Chanou
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Matthias Weiβ
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Karoline Holler
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany
- Institute of Computational Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Atiqa Sajid
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Tobias Straub
- Core Facility Bioinformatics, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Jana Krietsch
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Andrea Sanchi
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Henning Ummethum
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Clare S K Lee
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Elisabeth Kruse
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Manuel Trauner
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Marcel Werner
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Maxime Lalonde
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Antonio Scialdone
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany
- Institute of Computational Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Stephan Hamperl
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
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6
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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: 4] [Impact Index Per Article: 4.0] [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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7
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Sánchez H, Liu Z, van Veen E, van Laar T, Diffley JFX, Dekker NH. A chromatinized origin reduces the mobility of ORC and MCM through interactions and spatial constraint. Nat Commun 2023; 14:6735. [PMID: 37872142 PMCID: PMC10593741 DOI: 10.1038/s41467-023-42524-8] [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: 06/15/2023] [Accepted: 10/13/2023] [Indexed: 10/25/2023] Open
Abstract
Chromatin replication involves the assembly and activity of the replisome within the nucleosomal landscape. At the core of the replisome is the Mcm2-7 complex (MCM), which is loaded onto DNA after binding to the Origin Recognition Complex (ORC). In yeast, ORC is a dynamic protein that diffuses rapidly along DNA, unless halted by origin recognition sequences. However, less is known about the dynamics of ORC proteins in the presence of nucleosomes and attendant consequences for MCM loading. To address this, we harnessed an in vitro single-molecule approach to interrogate a chromatinized origin of replication. We find that ORC binds the origin of replication with similar efficiency independently of whether the origin is chromatinized, despite ORC mobility being reduced by the presence of nucleosomes. Recruitment of MCM also proceeds efficiently on a chromatinized origin, but subsequent movement of MCM away from the origin is severely constrained. These findings suggest that chromatinized origins in yeast are essential for the local retention of MCM, which may facilitate subsequent assembly of the replisome.
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Affiliation(s)
- Humberto Sánchez
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Zhaowei Liu
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Edo van Veen
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Theo van Laar
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - John F X Diffley
- Chromosome Replication Laboratory, Francis Crick Institute, London, United Kingdom
| | - Nynke H Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
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8
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Zhu L, Wang L, Liu D, Chen C, Mo K, Lan X, Liu J, Huang Y, Guo D, Huang H, Li M, Guo H, Tan J, Zhang K, Ji J, Yuan J, Ouyang H. Single-cell transcriptomics implicates the FEZ1-DKK1 axis in the regulation of corneal epithelial cell proliferation and senescence. Cell Prolif 2023; 56:e13433. [PMID: 36851859 PMCID: PMC10472519 DOI: 10.1111/cpr.13433] [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: 12/04/2022] [Revised: 02/07/2023] [Accepted: 02/16/2023] [Indexed: 03/01/2023] Open
Abstract
Limbal stem/progenitor cells (LSC) represent the source of corneal epithelium renewal. LSC proliferation and differentiation are essential for corneal homeostasis, however, the regulatory mechanism remains largely unexplored. Here, we performed single-cell RNA sequencing and discovered proliferation heterogeneity as well as spontaneously differentiated and senescent cell subgroups in multiply passaged primary LSC. Fasciculation and elongation protein zeta 1 (FEZ1) and Dickkopf-1 (DKK1) were identified as two significant regulators of LSC proliferation and senescence. These two factors were mainly expressed in undifferentiated corneal epithelial cells (CECs). Knocking down the expression of either FEZ1 or DKK1 reduced cell division and caused cell cycle arrest. We observed that DKK1 acted as a downstream target of FEZ1 in LSC and that exogenous DKK1 protein partially prevented growth arrest and senescence upon FEZ1 suppression in vitro. In a mouse model of corneal injury, DKK1 also rescued the corneal epithelium after recovery was inhibited by FEZ1 suppression. Hence, the FEZ1-DKK1 axis was required for CEC proliferation and the juvenile state and can potentially be targeted as a therapeutic strategy for promoting recovery after corneal injury.
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Affiliation(s)
- Liqiong Zhu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Li Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Dongmei Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Chaoqun Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Kunlun Mo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Xihong Lan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Jiafeng Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Ying Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Dianlei Guo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Huaxing Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Mingsen Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Huizhen Guo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Jieying Tan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Kang Zhang
- Center for Biomedicine and Innovations, Faculty of MedicineMacau University of Science and TechnologyChina
| | - Jianping Ji
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Jin Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
| | - Hong Ouyang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic CenterSun Yat‐sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science|GuangzhouChina
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9
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Poulet-Benedetti J, Tonnerre-Doncarli C, Valton AL, Laurent M, Gérard M, Barinova N, Parisis N, Massip F, Picard F, Prioleau MN. Dimeric G-quadruplex motifs-induced NFRs determine strong replication origins in vertebrates. Nat Commun 2023; 14:4843. [PMID: 37563125 PMCID: PMC10415359 DOI: 10.1038/s41467-023-40441-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 07/28/2023] [Indexed: 08/12/2023] Open
Abstract
Replication of vertebrate genomes is tightly regulated to ensure accurate duplication, but our understanding of the interplay between genetic and epigenetic factors in this regulation remains incomplete. Here, we investigated the involvement of three elements enriched at gene promoters and replication origins: guanine-rich motifs potentially forming G-quadruplexes (pG4s), nucleosome-free regions (NFRs), and the histone variant H2A.Z, in the firing of origins of replication in vertebrates. We show that two pG4s on the same DNA strand (dimeric pG4s) are sufficient to induce the assembly of an efficient minimal replication origin without inducing transcription in avian DT40 cells. Dimeric pG4s in replication origins are associated with formation of an NFR next to precisely-positioned nucleosomes enriched in H2A.Z on this minimal origin and genome-wide. Thus, our data suggest that dimeric pG4s are important for the organization and duplication of vertebrate genomes. It supports the hypothesis that a nucleosome close to an NFR is a shared signal for the formation of replication origins in eukaryotes.
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Affiliation(s)
| | | | - Anne-Laure Valton
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France
- Department of Systems Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Marc Laurent
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France
| | - Marie Gérard
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France
| | - Natalja Barinova
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France
| | - Nikolaos Parisis
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013, Paris, France
| | - Florian Massip
- MINES ParisTech, PSL-Research University, CBIO-Centre for Computational Biology, 75006, Paris, France
- Institut Curie, Paris, Cedex, France
- INSERM, U900, Paris, Cedex, France
| | - Franck Picard
- Laboratory of Biology and Modelling of the Cell, Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS, UMR5239, Université Claude Bernard Lyon 1, Lyon, France.
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10
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Chua GNL, Watters JW, Olinares PDB, Luo JA, Chait BT, Liu S. Differential dynamics specify MeCP2 function at methylated DNA and nucleosomes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.02.543478. [PMID: 37333354 PMCID: PMC10274721 DOI: 10.1101/2023.06.02.543478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Methyl-CpG-binding protein 2 (MeCP2) is an essential chromatin-binding protein whose mutations cause Rett syndrome (RTT), a leading cause of monogenic intellectual disabilities in females. Despite its significant biomedical relevance, the mechanism by which MeCP2 navigates the chromatin epigenetic landscape to regulate chromatin structure and gene expression remains unclear. Here, we used correlative single-molecule fluorescence and force microscopy to directly visualize the distribution and dynamics of MeCP2 on a variety of DNA and chromatin substrates. We found that MeCP2 exhibits differential diffusion dynamics when bound to unmethylated and methylated bare DNA. Moreover, we discovered that MeCP2 preferentially binds nucleosomes within the context of chromatinized DNA and stabilizes them from mechanical perturbation. The distinct behaviors of MeCP2 at bare DNA and nucleosomes also specify its ability to recruit TBLR1, a core component of the NCoR1/2 co-repressor complex. We further examined several RTT mutations and found that they disrupt different aspects of the MeCP2-chromatin interaction, rationalizing the heterogeneous nature of the disease. Our work reveals the biophysical basis for MeCP2's methylation-dependent activities and suggests a nucleosome-centric model for its genomic distribution and gene repressive functions. These insights provide a framework for delineating the multifaceted functions of MeCP2 and aid in our understanding of the molecular mechanisms of RTT.
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Affiliation(s)
- Gabriella N. L. Chua
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
- Tri-Institutional PhD Program in Chemical Biology, New York, NY, USA
| | - John W. Watters
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Paul Dominic B. Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Joshua A. Luo
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Brian T. Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
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11
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Liu D, Sonalkar J, Prasanth SG. ORChestra coordinates the replication and repair music. Bioessays 2023; 45:e2200229. [PMID: 36811379 PMCID: PMC10023367 DOI: 10.1002/bies.202200229] [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: 11/29/2022] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 02/24/2023]
Abstract
Error-free genome duplication and accurate cell division are critical for cell survival. In all three domains of life, bacteria, archaea, and eukaryotes, initiator proteins bind replication origins in an ATP-dependent manner, play critical roles in replisome assembly, and coordinate cell-cycle regulation. We discuss how the eukaryotic initiator, Origin recognition complex (ORC), coordinates different events during the cell cycle. We propose that ORC is the maestro driving the orchestra to coordinately perform the musical pieces of replication, chromatin organization, and repair.
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Affiliation(s)
- Dazhen Liu
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801 USA
| | - Jay Sonalkar
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801 USA
| | - Supriya G. Prasanth
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801 USA
- Cancer center at Illinois, UIUC
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12
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Chacin E, Reusswig KU, Furtmeier J, Bansal P, Karl LA, Pfander B, Straub T, Korber P, Kurat CF. Establishment and function of chromatin organization at replication origins. Nature 2023; 616:836-842. [PMID: 37020028 DOI: 10.1038/s41586-023-05926-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 03/03/2023] [Indexed: 04/07/2023]
Abstract
The origin recognition complex (ORC) is essential for initiation of eukaryotic chromosome replication as it loads the replicative helicase-the minichromosome maintenance (MCM) complex-at replication origins1. Replication origins display a stereotypic nucleosome organization with nucleosome depletion at ORC-binding sites and flanking arrays of regularly spaced nucleosomes2-4. However, how this nucleosome organization is established and whether this organization is required for replication remain unknown. Here, using genome-scale biochemical reconstitution with approximately 300 replication origins, we screened 17 purified chromatin factors from budding yeast and found that the ORC established nucleosome depletion over replication origins and flanking nucleosome arrays by orchestrating the chromatin remodellers INO80, ISW1a, ISW2 and Chd1. The functional importance of the nucleosome-organizing activity of the ORC was demonstrated by orc1 mutations that maintained classical MCM-loader activity but abrogated the array-generation activity of ORC. These mutations impaired replication through chromatin in vitro and were lethal in vivo. Our results establish that ORC, in addition to its canonical role as the MCM loader, has a second crucial function as a master regulator of nucleosome organization at the replication origin, a crucial prerequisite for efficient chromosome replication.
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Affiliation(s)
- Erika Chacin
- Biomedical Center Munich (BMC), Division of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, Martinsried, Germany
| | - Karl-Uwe Reusswig
- Max Planck Institute of Biochemistry, DNA Replication and Genome Integrity, Martinsried, Germany
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Jessica Furtmeier
- Biomedical Center Munich (BMC), Division of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, Martinsried, Germany
| | - Priyanka Bansal
- Biomedical Center Munich (BMC), Division of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, Martinsried, Germany
| | - Leonhard A Karl
- Max Planck Institute of Biochemistry, DNA Replication and Genome Integrity, Martinsried, Germany
| | - Boris Pfander
- Max Planck Institute of Biochemistry, DNA Replication and Genome Integrity, Martinsried, Germany
- Genome Maintenance Mechanisms in Health and Disease, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
- Institute of Genome Stability in Aging and Disease, CECAD, University of Cologne, Medical Faculty, Cologne, Germany
| | - Tobias Straub
- Core Facility Bioinformatics, BMC, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, Martinsried, Germany
| | - Philipp Korber
- Biomedical Center Munich (BMC), Division of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, Martinsried, Germany
| | - Christoph F Kurat
- Biomedical Center Munich (BMC), Division of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität in Munich, Martinsried, Germany.
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Mansisidor AR, Risca VI. Chromatin accessibility: methods, mechanisms, and biological insights. Nucleus 2022; 13:236-276. [PMID: 36404679 PMCID: PMC9683059 DOI: 10.1080/19491034.2022.2143106] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/23/2022] [Accepted: 10/30/2022] [Indexed: 11/22/2022] Open
Abstract
Access to DNA is a prerequisite to the execution of essential cellular processes that include transcription, replication, chromosomal segregation, and DNA repair. How the proteins that regulate these processes function in the context of chromatin and its dynamic architectures is an intensive field of study. Over the past decade, genome-wide assays and new imaging approaches have enabled a greater understanding of how access to the genome is regulated by nucleosomes and associated proteins. Additional mechanisms that may control DNA accessibility in vivo include chromatin compaction and phase separation - processes that are beginning to be understood. Here, we review the ongoing development of accessibility measurements, we summarize the different molecular and structural mechanisms that shape the accessibility landscape, and we detail the many important biological functions that are linked to chromatin accessibility.
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Affiliation(s)
- Andrés R. Mansisidor
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
| | - Viviana I. Risca
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
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14
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Origin recognition complex harbors an intrinsic nucleosome remodeling activity. Proc Natl Acad Sci U S A 2022; 119:e2211568119. [PMID: 36215487 PMCID: PMC9586268 DOI: 10.1073/pnas.2211568119] [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: 11/18/2022] Open
Abstract
Nucleosomes package the entire eukaryotic genome, yet enzymes need access to the DNA for numerous metabolic activities, such as replication and transcription. Eukaryotic origins of replication in Saccharomyces cerevisiae are AT rich and are generally nucleosome free for the binding of ORC (origin recognition complex). However, the nucleosome-free region often undergoes expansion during G1/S phase, presumably to make room for MCM double-hexamer formation that nucleates the 11-subunit helicase, CMG (Cdc45, Mcm2–7, Cdc45). While nucleosome remodelers could perform this function, in vitro studies indicate that nucleosome remodeling may be intrinsic to the replication machinery. Indeed, we find here that ORC contains an intrinsic nucleosome remodeling activity that is capable of ATP-stimulated removal of H2A-H2B from nucleosomes. Eukaryotic DNA replication is initiated at multiple chromosomal sites known as origins of replication that are specifically recognized by the origin recognition complex (ORC) containing multiple ATPase sites. In budding yeast, ORC binds to specific DNA sequences known as autonomously replicating sequences (ARSs) that are mostly nucleosome depleted. However, nucleosomes may still inhibit the licensing of some origins by occluding ORC binding and subsequent MCM helicase loading. Using purified proteins and single-molecule visualization, we find here that the ORC can eject histones from a nucleosome in an ATP-dependent manner. The ORC selectively evicts H2A-H2B dimers but leaves the (H3-H4)2 tetramer on DNA. It also discriminates canonical H2A from the H2A.Z variant, evicting the former while retaining the latter. Finally, the bromo-adjacent homology (BAH) domain of the Orc1 subunit is essential for ORC-mediated histone eviction. These findings suggest that the ORC is a bona fide nucleosome remodeler that functions to create a local chromatin environment optimal for origin activity.
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