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Nakatani T, Schauer T, Altamirano-Pacheco L, Klein KN, Ettinger A, Pal M, Gilbert DM, Torres-Padilla ME. Emergence of replication timing during early mammalian development. Nature 2024; 625:401-409. [PMID: 38123678 PMCID: PMC10781638 DOI: 10.1038/s41586-023-06872-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 11/16/2023] [Indexed: 12/23/2023]
Abstract
DNA replication enables genetic inheritance across the kingdoms of life. Replication occurs with a defined temporal order known as the replication timing (RT) programme, leading to organization of the genome into early- or late-replicating regions. RT is cell-type specific, is tightly linked to the three-dimensional nuclear organization of the genome1,2 and is considered an epigenetic fingerprint3. In spite of its importance in maintaining the epigenome4, the developmental regulation of RT in mammals in vivo has not been explored. Here, using single-cell Repli-seq5, we generated genome-wide RT maps of mouse embryos from the zygote to the blastocyst stage. Our data show that RT is initially not well defined but becomes defined progressively from the 4-cell stage, coinciding with strengthening of the A and B compartments. We show that transcription contributes to the precision of the RT programme and that the difference in RT between the A and B compartments depends on RNA polymerase II at zygotic genome activation. Our data indicate that the establishment of nuclear organization precedes the acquisition of defined RT features and primes the partitioning of the genome into early- and late-replicating domains. Our work sheds light on the establishment of the epigenome at the beginning of mammalian development and reveals the organizing principles of genome organization.
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Affiliation(s)
| | - Tamas Schauer
- Institute of Epigenetics and Stem Cells, Helmholtz Munich, Munich, Germany
| | | | - Kyle N Klein
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Andreas Ettinger
- Institute of Epigenetics and Stem Cells, Helmholtz Munich, Munich, Germany
| | - Mrinmoy Pal
- Institute of Epigenetics and Stem Cells, Helmholtz Munich, Munich, Germany
| | - David M Gilbert
- Laboratory of Chromosome Replication and Epigenome Regulation, San Diego Biomedical Research Institute, San Diego, CA, USA
| | - Maria-Elena Torres-Padilla
- Institute of Epigenetics and Stem Cells, Helmholtz Munich, Munich, Germany.
- Faculty of Biology, Ludwig-Maximilians Universität, Munich, Germany.
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2
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Meyer-Nava S, Shetty AV, Rivera-Mulia JC. Repli-seq Sample Preparation using Cell Sorting with Cell-Permeant Dyes. Curr Protoc 2023; 3:e945. [PMID: 38009262 PMCID: PMC10838012 DOI: 10.1002/cpz1.945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2023]
Abstract
Replication timing is significantly correlated with gene expression and chromatin organization, changes dynamically during cell differentiation, and is altered in diseased states. Genome-wide analysis of replication timing is performed in actively replicating cells by Repli-seq. Current methods for Repli-seq require cells to be fixed in large numbers. This is a barrier for sample types that are sensitive to fixation or are in very limited numbers. In this article, we outline optimized methods to process live cells and intact nuclei for Repli-seq. Our protocol enables the processing of a smaller number of cells per sample and reduces processing time and sample loss while obtaining high-quality data. Further, for samples that tend to form clumps and are difficult to dissociate into a single-cell suspension, we also outline methods for isolation, staining, and processing of nuclei for Repli-seq. The Repli-seq data obtained from live cells and intact nuclei are comparable to those obtained from the standard protocols. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Live cell isolation and staining Alternate Protocol: Nuclei isolation and staining.
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Affiliation(s)
- Silvia Meyer-Nava
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota
- Stem Cell Institute, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Anala V. Shetty
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota
- Stem Cell Institute, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Juan Carlos Rivera-Mulia
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, Minnesota
- Stem Cell Institute, University of Minnesota Medical School, Minneapolis, Minnesota
- Masonic Cancer Center, University of Minnesota Medical School, Minneapolis, Minnesota
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3
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da Costa-Nunes JA, Gierlinski M, Sasaki T, Haagensen EJ, Gilbert DM, Blow JJ. The location and development of Replicon Cluster Domains in early replicating DNA. Wellcome Open Res 2023; 8:158. [PMID: 37766844 PMCID: PMC10521077 DOI: 10.12688/wellcomeopenres.18742.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2023] [Indexed: 09/29/2023] Open
Abstract
Background: It has been known for many years that in metazoan cells, replication origins are organised into clusters where origins within each cluster fire near-synchronously. Despite clusters being a fundamental organising principle of metazoan DNA replication, the genomic location of origin clusters has not been documented. Methods: We synchronised human U2OS by thymidine block and release followed by L-mimosine block and release to create a population of cells progressing into S phase with a high degree of synchrony. At different times after release into S phase, cells were pulsed with EdU; the EdU-labelled DNA was then pulled down, sequenced and mapped onto the human genome. Results: The early replicating DNA showed features at a range of scales. Wavelet analysis showed that the major feature of the early replicating DNA was at a size of 500 kb, consistent with clusters of replication origins. Over the first two hours of S phase, these Replicon Cluster Domains broadened in width, consistent with their being enlarged by the progression of replication forks at their outer boundaries. The total replication signal associated with each Replicon Cluster Domain varied considerably, and this variation was reproducible and conserved over time. We provide evidence that this variability in replication signal was at least in part caused by Replicon Cluster Domains being activated at different times in different cells in the population. We also provide evidence that adjacent clusters had a statistical preference for being activated in sequence across a group, consistent with the 'domino' model of replication focus activation order observed by microscopy. Conclusions: We show that early replicating DNA is organised into Replicon Cluster Domains that behave as expected of replicon clusters observed by DNA fibre analysis. The coordinated activation of different Replicon Cluster Domains can generate the replication timing programme by which the genome is duplicated.
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Affiliation(s)
- José A. da Costa-Nunes
- Division of Molecular, Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Marek Gierlinski
- Data Analysis Group, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Takayo Sasaki
- San Diego Biomedical Research Institute, San Diego, California, CA 92121, USA
| | - Emma J. Haagensen
- Division of Molecular, Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
- Present address: School of Medical Education, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - David M. Gilbert
- San Diego Biomedical Research Institute, San Diego, California, CA 92121, USA
| | - J. Julian Blow
- Division of Molecular, Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
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4
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Rivera-Mulia JC, Trevilla-Garcia C, Martinez-Cifuentes S. Optimized Repli-seq: improved DNA replication timing analysis by next-generation sequencing. Chromosome Res 2022; 30:401-414. [PMID: 35781769 PMCID: PMC10124313 DOI: 10.1007/s10577-022-09703-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 06/15/2022] [Accepted: 06/15/2022] [Indexed: 01/25/2023]
Abstract
The human genome is divided into functional units that replicate at specific times during S-phase. This temporal program is known as replication timing (RT) and is coordinated with the spatial organization of the genome and transcriptional activity. RT is also cell type-specific, dynamically regulated during development, and alterations in RT are observed in multiple diseases. Thus, the precise measure of RT is critical to understand the role of RT in gene function regulation. Distinct methods for assaying the RT program exist; however, conventional methods require thousands of cells as input, prohibiting its applicability to samples with limited cell numbers such as those from disease patients or from early developing embryos. Although single-cell RT analyses have been developed, these methods are low throughput, require generation of numerous libraries, increased sequencing costs, and produce low resolution data. Here, we developed an improved method to measure RT genome-wide that enables high-resolution analysis of low input samples. This method incorporates direct cell sorting into lysis buffer, as well as DNA fragmentation and library preparation in a single tube, resulting in higher yields, increased quality, and reproducibility with decreased costs. We also performed a systematic data processing analysis to provide standardized parameters for RT measurement. This optimized method facilitates RT analysis and will enable its application to a broad range of studies investigating the role of RT in gene expression, nuclear architecture, and disease.
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Affiliation(s)
- Juan Carlos Rivera-Mulia
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN, USA.
- Stem Cell Institute, University of Minnesota Medical School, Minneapolis, MN, USA.
- Masonic Cancer Center, University of Minnesota Medical School, Minneapolis, MN, USA.
| | - Claudia Trevilla-Garcia
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Santiago Martinez-Cifuentes
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN, USA
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5
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Massey DJ, Koren A. Telomere-to-telomere human DNA replication timing profiles. Sci Rep 2022; 12:9560. [PMID: 35688856 PMCID: PMC9187705 DOI: 10.1038/s41598-022-13638-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/26/2022] [Indexed: 11/23/2022] Open
Abstract
The spatiotemporal organization of DNA replication produces a highly robust and reproducible replication timing profile. Sequencing-based methods for assaying replication timing genome-wide have become commonplace, but regions of high repeat content in the human genome have remained refractory to analysis. Here, we report the first nearly-gapless telomere-to-telomere replication timing profiles in human, using the T2T-CHM13 genome assembly and sequencing data for five cell lines. We find that replication timing can be successfully assayed in centromeres and large blocks of heterochromatin. Centromeric regions replicate in mid-to-late S-phase and contain replication-timing peaks at a similar density to other genomic regions, while distinct families of heterochromatic satellite DNA differ in their bias for replicating in late S-phase. The high degree of consistency in centromeric replication timing across chromosomes within each cell line prompts further investigation into the mechanisms dictating that some cell lines replicate their centromeres earlier than others, and what the consequences of this variation are.
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Affiliation(s)
- Dashiell J Massey
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Amnon Koren
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA.
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6
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Nakatani T, Lin J, Ji F, Ettinger A, Pontabry J, Tokoro M, Altamirano-Pacheco L, Fiorentino J, Mahammadov E, Hatano Y, Van Rechem C, Chakraborty D, Ruiz-Morales ER, Arguello Pascualli PY, Scialdone A, Yamagata K, Whetstine JR, Sadreyev RI, Torres-Padilla ME. DNA replication fork speed underlies cell fate changes and promotes reprogramming. Nat Genet 2022; 54:318-327. [PMID: 35256805 PMCID: PMC8920892 DOI: 10.1038/s41588-022-01023-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 01/27/2022] [Indexed: 01/29/2023]
Abstract
Totipotency emerges in early embryogenesis, but its molecular underpinnings remain poorly characterized. In the present study, we employed DNA fiber analysis to investigate how pluripotent stem cells are reprogrammed into totipotent-like 2-cell-like cells (2CLCs). We show that totipotent cells of the early mouse embryo have slow DNA replication fork speed and that 2CLCs recapitulate this feature, suggesting that fork speed underlies the transition to a totipotent-like state. 2CLCs emerge concomitant with DNA replication and display changes in replication timing (RT), particularly during the early S-phase. RT changes occur prior to 2CLC emergence, suggesting that RT may predispose to gene expression changes and consequent reprogramming of cell fate. Slowing down replication fork speed experimentally induces 2CLCs. In vivo, slowing fork speed improves the reprogramming efficiency of somatic cell nuclear transfer. Our data suggest that fork speed regulates cellular plasticity and that remodeling of replication features leads to changes in cell fate and reprogramming. Totipotent cells in mouse embryos and 2-cell-like cells have slow DNA replication fork speed. Perturbations that slow replication fork speed promote 2-cell-like cell emergence and improve somatic cell nuclear transfer reprogramming and formation of induced pluripotent stem cell colonies.
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7
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Chemically Induced Chromosomal Interaction (CICI) method to study chromosome dynamics and its biological roles. Nat Commun 2022; 13:757. [PMID: 35140210 PMCID: PMC8828778 DOI: 10.1038/s41467-022-28416-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 01/14/2022] [Indexed: 01/01/2023] Open
Abstract
Numerous intra- and inter-chromosomal contacts have been mapped in eukaryotic genomes, but it remains challenging to link these 3D structures to their regulatory functions. To establish the causal relationships between chromosome conformation and genome functions, we develop a method, Chemically Induced Chromosomal Interaction (CICI), to selectively perturb the chromosome conformation at targeted loci. Using this method, long-distance chromosomal interactions can be induced dynamically between intra- or inter-chromosomal loci pairs, including the ones with very low Hi-C contact frequencies. Measurement of CICI formation time allows us to probe chromosome encounter dynamics between different loci pairs across the cell cycle. We also conduct two functional tests of CICI. We perturb the chromosome conformation near a DNA double-strand break and observe altered donor preference in homologous recombination; we force interactions between early and late-firing DNA replication origins and find no significant changes in replication timing. These results suggest that chromosome conformation plays a deterministic role in homology-directed DNA repair, but not in the establishment of replication timing. Overall, our study demonstrates that CICI is a powerful tool to study chromosome dynamics and 3D genome function. Methods to selectively manipulate specific long-distance chromosomal interactions are limited. Here the authors develop a method called Chemically Induced Chromosomal Interaction (CICI) to engineer interactions and demonstrate that 3D conformation plays a causal role in establishing donor DNA preference during DNA repair.
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8
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Ben Yamin B, Ahmed-Seghir S, Tomida J, Despras E, Pouvelle C, Yurchenko A, Goulas J, Corre R, Delacour Q, Droin N, Dessen P, Goidin D, Lange SS, Bhetawal S, Mitjavila-Garcia MT, Baldacci G, Nikolaev S, Cadoret JC, Wood RD, Kannouche PL. DNA polymerase zeta contributes to heterochromatin replication to prevent genome instability. EMBO J 2021; 40:e104543. [PMID: 34533226 PMCID: PMC8561639 DOI: 10.15252/embj.2020104543] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 08/20/2021] [Accepted: 08/28/2021] [Indexed: 02/06/2023] Open
Abstract
The DNA polymerase zeta (Polζ) plays a critical role in bypassing DNA damage. REV3L, the catalytic subunit of Polζ, is also essential in mouse embryonic development and cell proliferation for reasons that remain incompletely understood. In this study, we reveal that REV3L protein interacts with heterochromatin components including repressive histone marks and localizes in pericentromeric regions through direct interaction with HP1 dimer. We demonstrate that Polζ/REV3L ensures progression of replication forks through difficult‐to‐replicate pericentromeric heterochromatin, thereby preventing spontaneous chromosome break formation. We also find that Rev3l‐deficient cells are compromised in the repair of heterochromatin‐associated double‐stranded breaks, eliciting deletions in late‐replicating regions. Lack of REV3L leads to further consequences that may be ascribed to heterochromatin replication and repair‐associated functions of Polζ, with a disruption of the temporal replication program at specific loci. This is correlated with changes in epigenetic landscape and transcriptional control of developmentally regulated genes. These results reveal a new function of Polζ in preventing chromosome instability during replication of heterochromatic regions.
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Affiliation(s)
- Barbara Ben Yamin
- CNRS-UMR9019, Equipe labellisée Ligue Contre le Cancer, Gustave Roussy, Paris-Saclay Université, Villejuif, France
| | - Sana Ahmed-Seghir
- CNRS-UMR9019, Equipe labellisée Ligue Contre le Cancer, Gustave Roussy, Paris-Saclay Université, Villejuif, France
| | - Junya Tomida
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center and The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Emmanuelle Despras
- CNRS-UMR9019, Equipe labellisée Ligue Contre le Cancer, Gustave Roussy, Paris-Saclay Université, Villejuif, France
| | - Caroline Pouvelle
- CNRS-UMR9019, Equipe labellisée Ligue Contre le Cancer, Gustave Roussy, Paris-Saclay Université, Villejuif, France
| | - Andrey Yurchenko
- INSERM U981, Gustave Roussy, Université Paris Saclay, Villejuif, France
| | - Jordane Goulas
- CNRS-UMR9019, Equipe labellisée Ligue Contre le Cancer, Gustave Roussy, Paris-Saclay Université, Villejuif, France
| | - Raphael Corre
- CNRS-UMR9019, Equipe labellisée Ligue Contre le Cancer, Gustave Roussy, Paris-Saclay Université, Villejuif, France
| | - Quentin Delacour
- CNRS-UMR9019, Equipe labellisée Ligue Contre le Cancer, Gustave Roussy, Paris-Saclay Université, Villejuif, France
| | | | - Philippe Dessen
- Bioinformatics Core Facility, Gustave Roussy, Villejuif, France
| | - Didier Goidin
- Life Sciences and Diagnostics Group, Agilent Technologies France, Les Ulis, France
| | - Sabine S Lange
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center and The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Sarita Bhetawal
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center and The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, TX, USA
| | | | - Giuseppe Baldacci
- Institut Jacques Monod, UMR7592, CNRS and University of Paris, Paris, France
| | - Sergey Nikolaev
- INSERM U981, Gustave Roussy, Université Paris Saclay, Villejuif, France
| | | | - Richard D Wood
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center and The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Patricia L Kannouche
- CNRS-UMR9019, Equipe labellisée Ligue Contre le Cancer, Gustave Roussy, Paris-Saclay Université, Villejuif, France
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9
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Li Y, Xue B, Zhang M, Zhang L, Hou Y, Qin Y, Long H, Su QP, Wang Y, Guan X, Jin Y, Cao Y, Li G, Sun Y. Transcription-coupled structural dynamics of topologically associating domains regulate replication origin efficiency. Genome Biol 2021; 22:206. [PMID: 34253239 PMCID: PMC8276456 DOI: 10.1186/s13059-021-02424-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 06/30/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Metazoan cells only utilize a small subset of the potential DNA replication origins to duplicate the whole genome in each cell cycle. Origin choice is linked to cell growth, differentiation, and replication stress. Although various genetic and epigenetic signatures have been linked to the replication efficiency of origins, there is no consensus on how the selection of origins is determined. RESULTS We apply dual-color stochastic optical reconstruction microscopy (STORM) super-resolution imaging to map the spatial distribution of origins within individual topologically associating domains (TADs). We find that multiple replication origins initiate separately at the spatial boundary of a TAD at the beginning of the S phase. Intriguingly, while both high-efficiency and low-efficiency origins are distributed homogeneously in the TAD during the G1 phase, high-efficiency origins relocate to the TAD periphery before the S phase. Origin relocalization is dependent on both transcription and CTCF-mediated chromatin structure. Further, we observe that the replication machinery protein PCNA forms immobile clusters around TADs at the G1/S transition, explaining why origins at the TAD periphery are preferentially fired. CONCLUSION Our work reveals a new origin selection mechanism that the replication efficiency of origins is determined by their physical distribution in the chromatin domain, which undergoes a transcription-dependent structural re-organization process. Our model explains the complex links between replication origin efficiency and many genetic and epigenetic signatures that mark active transcription. The coordination between DNA replication, transcription, and chromatin organization inside individual TADs also provides new insights into the biological functions of sub-domain chromatin structural dynamics.
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Affiliation(s)
- Yongzheng Li
- State Key Laboratory of Membrane Biology, Biomedical Pioneer Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing, 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Boxin Xue
- State Key Laboratory of Membrane Biology, Biomedical Pioneer Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing, 100871, China
- College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Mengling Zhang
- State Key Laboratory of Membrane Biology, Biomedical Pioneer Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing, 100871, China
| | - Liwei Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yingping Hou
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Yizhi Qin
- State Key Laboratory of Membrane Biology, Biomedical Pioneer Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing, 100871, China
| | - Haizhen Long
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Qian Peter Su
- State Key Laboratory of Membrane Biology, Biomedical Pioneer Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing, 100871, China
- School of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Yao Wang
- State Key Laboratory of Membrane Biology, Biomedical Pioneer Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing, 100871, China
| | - Xiaodong Guan
- State Key Laboratory of Membrane Biology, Biomedical Pioneer Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing, 100871, China
| | - Yanyan Jin
- Department of Neurobiology, Beijing Centre of Neural Regeneration and Repair, Capital Medical University, Beijing, 100101, China
| | - Yuan Cao
- State Key Laboratory of Membrane Biology, Biomedical Pioneer Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing, 100871, China
| | - Guohong Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yujie Sun
- State Key Laboratory of Membrane Biology, Biomedical Pioneer Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing, 100871, China.
- College of Future Technology, Peking University, Beijing, 100871, China.
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10
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Strobino M, Wenda JM, Padayachy L, Steiner FA. Loss of histone H3.3 results in DNA replication defects and altered origin dynamics in C. elegans. Genome Res 2020; 30:1740-1751. [PMID: 33172964 PMCID: PMC7706726 DOI: 10.1101/gr.260794.120] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 10/06/2020] [Indexed: 12/12/2022]
Abstract
Histone H3.3 is a replication-independent variant of histone H3 with important roles in development, differentiation, and fertility. Here, we show that loss of H3.3 results in replication defects in Caenorhabditis elegans embryos at elevated temperatures. To characterize these defects, we adapt methods to determine replication timing, map replication origins, and examine replication fork progression. Our analysis of the spatiotemporal regulation of DNA replication shows that despite the very rapid embryonic cell cycle, the genome is replicated from early and late firing origins and is partitioned into domains of early and late replication. We find that under temperature stress conditions, additional replication origins become activated. Moreover, loss of H3.3 results in altered replication fork progression around origins, which is particularly evident at stress-activated origins. These replication defects are accompanied by replication checkpoint activation, a delayed cell cycle, and increased lethality in checkpoint-compromised embryos. Our comprehensive analysis of DNA replication in C. elegans reveals the genomic location of replication origins and the dynamics of their firing, and uncovers a role of H3.3 in the regulation of replication origins under stress conditions.
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Affiliation(s)
- Maude Strobino
- Department of Molecular Biology and Institute for Genetics and Genomics in Geneva, Section of Biology, Faculty of Sciences, University of Geneva, 1211 Geneva, Switzerland
| | - Joanna M Wenda
- Department of Molecular Biology and Institute for Genetics and Genomics in Geneva, Section of Biology, Faculty of Sciences, University of Geneva, 1211 Geneva, Switzerland
| | - Laura Padayachy
- Department of Molecular Biology and Institute for Genetics and Genomics in Geneva, Section of Biology, Faculty of Sciences, University of Geneva, 1211 Geneva, Switzerland
| | - Florian A Steiner
- Department of Molecular Biology and Institute for Genetics and Genomics in Geneva, Section of Biology, Faculty of Sciences, University of Geneva, 1211 Geneva, Switzerland
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11
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Zhao PA, Sasaki T, Gilbert DM. High-resolution Repli-Seq defines the temporal choreography of initiation, elongation and termination of replication in mammalian cells. Genome Biol 2020; 21:76. [PMID: 32209126 PMCID: PMC7092589 DOI: 10.1186/s13059-020-01983-8] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/04/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND DNA replication in mammalian cells occurs in a defined temporal order during S phase, known as the replication timing (RT) programme. Replication timing is developmentally regulated and correlated with chromatin conformation and local transcriptional potential. Here, we present RT profiles of unprecedented temporal resolution in two human embryonic stem cell lines, human colon carcinoma line HCT116, and mouse embryonic stem cells and their neural progenitor derivatives. RESULTS Fine temporal windows revealed a remarkable degree of cell-to-cell conservation in RT, particularly at the very beginning and ends of S phase, and identified 5 temporal patterns of replication in all cell types, consistent with varying degrees of initiation efficiency. Zones of replication initiation (IZs) were detected throughout S phase and interacted in 3D space preferentially with other IZs of similar firing time. Temporal transition regions were resolved into segments of uni-directional replication punctuated at specific sites by small, inefficient IZs. Sites of convergent replication were divided into sites of termination or large constant timing regions consisting of many synchronous IZs in tandem. Developmental transitions in RT occured mainly by activating or inactivating individual IZs or occasionally by altering IZ firing time, demonstrating that IZs, rather than individual origins, are the units of developmental regulation. Finally, haplotype phasing revealed numerous regions of allele-specific and allele-independent asynchronous replication. Allele-independent asynchronous replication was correlated with the presence of previously mapped common fragile sites. CONCLUSIONS Altogether, these data provide a detailed temporal choreography of DNA replication in mammalian cells.
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Affiliation(s)
- Peiyao A Zhao
- Department of Biological Science, Florida State University, 319 Stadium Drive, Tallahassee, FL, 32306, USA
| | - Takayo Sasaki
- Department of Biological Science, Florida State University, 319 Stadium Drive, Tallahassee, FL, 32306, USA
| | - David M Gilbert
- Department of Biological Science, Florida State University, 319 Stadium Drive, Tallahassee, FL, 32306, USA.
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12
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Hulke ML, Massey DJ, Koren A. Genomic methods for measuring DNA replication dynamics. Chromosome Res 2020; 28:49-67. [PMID: 31848781 PMCID: PMC7131883 DOI: 10.1007/s10577-019-09624-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/30/2019] [Accepted: 12/03/2019] [Indexed: 12/27/2022]
Abstract
Genomic DNA replicates according to a defined temporal program in which early-replicating loci are associated with open chromatin, higher gene density, and increased gene expression levels, while late-replicating loci tend to be heterochromatic and show higher rates of genomic instability. The ability to measure DNA replication dynamics at genome scale has proven crucial for understanding the mechanisms and cellular consequences of DNA replication timing. Several methods, such as quantification of nucleotide analog incorporation and DNA copy number analyses, can accurately reconstruct the genomic replication timing profiles of various species and cell types. More recent developments have expanded the DNA replication genomic toolkit to assays that directly measure the activity of replication origins, while single-cell replication timing assays are beginning to reveal a new level of replication timing regulation. The combination of these methods, applied on a genomic scale and in multiple biological systems, promises to resolve many open questions and lead to a holistic understanding of how eukaryotic cells replicate their genomes accurately and efficiently.
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Affiliation(s)
- Michelle L Hulke
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Dashiell J Massey
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Amnon Koren
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA.
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13
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Massip F, Laurent M, Brossas C, Fernández-Justel JM, Gómez M, Prioleau MN, Duret L, Picard F. Evolution of replication origins in vertebrate genomes: rapid turnover despite selective constraints. Nucleic Acids Res 2019; 47:5114-5125. [PMID: 30916335 PMCID: PMC6547456 DOI: 10.1093/nar/gkz182] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 02/28/2019] [Accepted: 03/11/2019] [Indexed: 01/03/2023] Open
Abstract
The replication program of vertebrate genomes is driven by the chromosomal distribution and timing of activation of tens of thousands of replication origins. Genome-wide studies have shown the association of origins with promoters and CpG islands, and their enrichment in G-quadruplex motifs (G4). However, the genetic determinants driving their activity remain poorly understood. To gain insight on the constraints operating on origins, we conducted the first evolutionary comparison of origins across vertebrates. We generated a genome-wide map of chicken origins (the first of a bird genome), and performed a comparison with human and mouse maps. The analysis of intra-species polymorphism revealed a strong depletion of genetic diversity at the core of replication initiation loci. This depletion is not linked to the presence of G4 motifs, promoters or CpG islands. In contrast, we show that origins experienced a rapid turnover during vertebrate evolution, since pairwise comparisons of origin maps revealed that <24% of them are conserved among vertebrates. This study unravels the existence of a novel determinant of origins, the precise functional role of which remains to be determined. Despite the importance of replication initiation for the fitness of organisms, the distribution of origins along vertebrate chromosomes is highly flexible.
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Affiliation(s)
- Florian Massip
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, Villleurbanne, France.,Berlin Institute for Medical Systems Biology, Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Marc Laurent
- Institut Jacques Monod, CNRS UMR7592, Université Paris Diderot, Equipe Labellisée Association pour la Recherche sur le Cancer, Paris, France
| | - Caroline Brossas
- Institut Jacques Monod, CNRS UMR7592, Université Paris Diderot, Equipe Labellisée Association pour la Recherche sur le Cancer, Paris, France
| | | | - María Gómez
- Centro de Biología Molecular Severo Ochoa CBMSO (CSIC/UAM). Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Marie-Noelle Prioleau
- Institut Jacques Monod, CNRS UMR7592, Université Paris Diderot, Equipe Labellisée Association pour la Recherche sur le Cancer, Paris, France
| | - Laurent Duret
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, Villleurbanne, France
| | - Franck Picard
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, Villleurbanne, France
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14
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Control of DNA replication timing in the 3D genome. Nat Rev Mol Cell Biol 2019; 20:721-737. [DOI: 10.1038/s41580-019-0162-y] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2019] [Indexed: 12/27/2022]
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15
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Yehuda Y, Blumenfeld B, Mayorek N, Makedonski K, Vardi O, Cohen-Daniel L, Mansour Y, Baror-Sebban S, Masika H, Farago M, Berger M, Carmi S, Buganim Y, Koren A, Simon I. Germline DNA replication timing shapes mammalian genome composition. Nucleic Acids Res 2019; 46:8299-8310. [PMID: 29986092 PMCID: PMC6144785 DOI: 10.1093/nar/gky610] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 06/26/2018] [Indexed: 12/13/2022] Open
Abstract
Mammalian DNA replication is a highly organized and regulated process. Large, Mb-sized regions are replicated at defined times along S-phase. Replication Timing (RT) is thought to play a role in shaping the mammalian genome by affecting mutation rates. Previous analyses relied on somatic RT profiles. However, only germline mutations are passed on to offspring and affect genomic composition. Therefore, germ cell RT information is necessary to evaluate the influences of RT on the mammalian genome. We adapted the RT mapping technique for limited amounts of cells, and measured RT from two stages in the mouse germline - primordial germ cells (PGCs) and spermatogonial stem cells (SSCs). RT in germline cells exhibited stronger correlations to both mutation rate and recombination hotspots density than those of RT in somatic tissues, emphasizing the importance of using correct tissues-of-origin for RT profiling. Germline RT maps exhibited stronger correlations to additional genetic features including GC-content, transposable elements (SINEs and LINEs), and gene density. GC content stratification and multiple regression analysis revealed independent contributions of RT to SINE, gene, mutation, and recombination hotspot densities. Together, our results establish a central role for RT in shaping multiple levels of mammalian genome composition.
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Affiliation(s)
- Yishai Yehuda
- Department of Microbiology and Molecular Genetics, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel.,Department of Bioinformatics, Jerusalem College of Technology, Jerusalem, Israel
| | - Britny Blumenfeld
- Department of Microbiology and Molecular Genetics, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Nina Mayorek
- The Concern Foundation Laboratories at The Lautenberg Center for Immunology and Cancer Research, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem, Israel
| | - Kirill Makedonski
- Department of Developmental Biology and Cancer Research, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Oriya Vardi
- Department of Microbiology and Molecular Genetics, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Leonor Cohen-Daniel
- The Concern Foundation Laboratories at The Lautenberg Center for Immunology and Cancer Research, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem, Israel
| | - Yousef Mansour
- The Concern Foundation Laboratories at The Lautenberg Center for Immunology and Cancer Research, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem, Israel
| | - Shulamit Baror-Sebban
- Department of Developmental Biology and Cancer Research, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hagit Masika
- Department of Developmental Biology and Cancer Research, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Marganit Farago
- Department of Developmental Biology and Cancer Research, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Michael Berger
- The Concern Foundation Laboratories at The Lautenberg Center for Immunology and Cancer Research, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem, Israel
| | - Shai Carmi
- Braun School of Public Health and Community Medicine, the Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yosef Buganim
- Department of Developmental Biology and Cancer Research, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Amnon Koren
- Deptartment of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Itamar Simon
- Department of Microbiology and Molecular Genetics, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
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16
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Heinz KS, Casas-Delucchi CS, Török T, Cmarko D, Rapp A, Raska I, Cardoso MC. Peripheral re-localization of constitutive heterochromatin advances its replication timing and impairs maintenance of silencing marks. Nucleic Acids Res 2019; 46:6112-6128. [PMID: 29750270 PMCID: PMC6158597 DOI: 10.1093/nar/gky368] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 04/25/2018] [Indexed: 11/13/2022] Open
Abstract
The replication of the genome is a highly organized process, both spatially and temporally. Although a lot is known on the composition of the basic replication machinery, how its activity is regulated is mostly unknown. Several chromatin properties have been proposed as regulators, but a potential role of the nuclear DNA position remains unclear. We made use of the prominent structure and well-defined heterochromatic landscape of mouse pericentric chromosome domains as a well-studied example of late replicating constitutive heterochromatin. We established a method to manipulate its nuclear position and evaluated the effect on replication timing, DNA compaction and epigenetic composition. Using time-lapse microscopy, we observed that constitutive heterochromatin, known to replicate during late S-phase, was replicated in mid S-phase when repositioned to the nuclear periphery. Out-of-schedule replication resulted in deficient post-replicative maintenance of chromatin modifications, namely silencing marks. We propose that repositioned constitutive heterochromatin was activated in trans according to the domino model of origin firing by nearby (mid S) firing origins. In summary, our data provide, on the one hand, a novel approach to manipulate nuclear DNA position and, on the other hand, establish nuclear DNA position as a novel mechanism regulating DNA replication timing and epigenetic maintenance.
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Affiliation(s)
- Kathrin S Heinz
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Corella S Casas-Delucchi
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Timea Török
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Dusan Cmarko
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 00 Prague, Czech Republic
| | - Alexander Rapp
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Ivan Raska
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 00 Prague, Czech Republic
| | - M Cristina Cardoso
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany
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17
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Clinical and pathological significance of Homo sapiens ceramide synthase 2 (CerS-2) in diverse human cancers. Biosci Rep 2019; 39:BSR20181743. [PMID: 30988071 PMCID: PMC6504659 DOI: 10.1042/bsr20181743] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 02/22/2019] [Accepted: 04/12/2019] [Indexed: 01/10/2023] Open
Abstract
Homo sapiens ceramide synthase 2 (CerS-2) plays an important role in inhibiting invasion and metastasis of tumor cells and has been reported as a tumor metastasis suppressor gene in diverse cancers. Thus, low level of CerS-2 protein might suggest a bad prognosis and up-regulation of CerS-2 protein might act as a promising therapeutic strategy for malignant tumors. In this review, we discussed the expression, as well as the clinical and pathological significance of CerS-2 in diverse human cancers. The pathological processes and molecular pathways regulated by CerS-2 were also summarized.
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18
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Massey DJ, Kim D, Brooks KE, Smolka MB, Koren A. Next-Generation Sequencing Enables Spatiotemporal Resolution of Human Centromere Replication Timing. Genes (Basel) 2019; 10:genes10040269. [PMID: 30987063 PMCID: PMC6523654 DOI: 10.3390/genes10040269] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/25/2019] [Accepted: 03/29/2019] [Indexed: 12/15/2022] Open
Abstract
Centromeres serve a critical function in preserving genome integrity across sequential cell divisions, by mediating symmetric chromosome segregation. The repetitive, heterochromatic nature of centromeres is thought to be inhibitory to DNA replication, but has also led to their underrepresentation in human reference genome assemblies. Consequently, centromeres have been excluded from genomic replication timing analyses, leaving their time of replication unresolved. However, the most recent human reference genome, hg38, included models of centromere sequences. To establish the experimental requirements for achieving replication timing profiles for centromeres, we sequenced G1- and S-phase cells from five human cell lines, and aligned the sequence reads to hg38. We were able to infer DNA replication timing profiles for the centromeres in each of the five cell lines, which showed that centromere replication occurs in mid-to-late S phase. Furthermore, we found that replication timing was more variable between cell lines in the centromere regions than expected, given the distribution of variation in replication timing genome-wide. These results suggest the potential of these, and future, sequence models to enable high-resolution studies of replication in centromeres and other heterochromatic regions.
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Affiliation(s)
- Dashiell J Massey
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
| | - Dongsung Kim
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.
| | - Kayla E Brooks
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
| | - Marcus B Smolka
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.
| | - Amnon Koren
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
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19
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Chu Y, Teng M, Wang Y. Modeling and correct the GC bias of tumor and normal WGS data for SCNA based tumor subclonal population inferring. BMC Bioinformatics 2018; 19:112. [PMID: 29671389 PMCID: PMC5907144 DOI: 10.1186/s12859-018-2099-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Somatic copy number alternations (SCNAs) can be utilized to infer tumor subclonal populations in whole genome seuqncing studies, where usually their read count ratios between tumor-normal paired samples serve as the inferring proxy. Existing SCNA based subclonal population inferring tools consider the GC bias of tumor and normal sample is of the same fature, and could be fully offset by read count ratio. However, we found that, the read count ratio on SCNA segments presents a Log linear biased pattern, which influence existing read count ratios based subclonal inferring tools performance. Currently no correction tools take into account the read ratio bias. RESULTS We present Pre-SCNAClonal, a tool that improving tumor subclonal population inferring by correcting GC-bias at SCNAs level. Pre-SCNAClonal first corrects GC bias using Markov chain Monte Carlo probability model, then accurately locates baseline DNA segments (not containing any SCNAs) with a hierarchy clustering model. We show Pre-SCNAClonal's superiority to exsiting GC-bias correction methods at any level of subclonal population. CONCLUSIONS Pre-SCNAClonal could be run independently as well as serving as pre-processing/gc-correction step in conjuntion with exsiting SCNA-based subclonal inferring tools.
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Affiliation(s)
- Yanshuo Chu
- Center for Bioinformatics, Harbin Institute of Technology, Harbin, China
| | - Mingxiang Teng
- Center for Bioinformatics, Harbin Institute of Technology, Harbin, China
| | - Yadong Wang
- Center for Bioinformatics, Harbin Institute of Technology, Harbin, China.
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20
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Wear EE, Song J, Zynda GJ, LeBlanc C, Lee TJ, Mickelson-Young L, Concia L, Mulvaney P, Szymanski ES, Allen GC, Martienssen RA, Vaughn MW, Hanley-Bowdoin L, Thompson WF. Genomic Analysis of the DNA Replication Timing Program during Mitotic S Phase in Maize ( Zea mays) Root Tips. THE PLANT CELL 2017; 29:2126-2149. [PMID: 28842533 PMCID: PMC5635974 DOI: 10.1105/tpc.17.00037] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 07/31/2017] [Accepted: 08/24/2017] [Indexed: 05/19/2023]
Abstract
All plants and animals must replicate their DNA, using a regulated process to ensure that their genomes are completely and accurately replicated. DNA replication timing programs have been extensively studied in yeast and animal systems, but much less is known about the replication programs of plants. We report a novel adaptation of the "Repli-seq" assay for use in intact root tips of maize (Zea mays) that includes several different cell lineages and present whole-genome replication timing profiles from cells in early, mid, and late S phase of the mitotic cell cycle. Maize root tips have a complex replication timing program, including regions of distinct early, mid, and late S replication that each constitute between 20 and 24% of the genome, as well as other loci corresponding to ∼32% of the genome that exhibit replication activity in two different time windows. Analyses of genomic, transcriptional, and chromatin features of the euchromatic portion of the maize genome provide evidence for a gradient of early replicating, open chromatin that transitions gradually to less open and less transcriptionally active chromatin replicating in mid S phase. Our genomic level analysis also demonstrated that the centromere core replicates in mid S, before heavily compacted classical heterochromatin, including pericentromeres and knobs, which replicate during late S phase.
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Affiliation(s)
- Emily E Wear
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Jawon Song
- Texas Advanced Computing Center, University of Texas, Austin, Texas 78758
| | - Gregory J Zynda
- Texas Advanced Computing Center, University of Texas, Austin, Texas 78758
| | - Chantal LeBlanc
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| | - Tae-Jin Lee
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Leigh Mickelson-Young
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Lorenzo Concia
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Patrick Mulvaney
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Eric S Szymanski
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - George C Allen
- Department of Horticultural Science, North Carolina State University, Raleigh, North Carolina 27695
| | | | - Matthew W Vaughn
- Texas Advanced Computing Center, University of Texas, Austin, Texas 78758
| | - Linda Hanley-Bowdoin
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - William F Thompson
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
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21
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Zynda GJ, Song J, Concia L, Wear EE, Hanley-Bowdoin L, Thompson WF, Vaughn MW. Repliscan: a tool for classifying replication timing regions. BMC Bioinformatics 2017; 18:362. [PMID: 28784090 PMCID: PMC5547489 DOI: 10.1186/s12859-017-1774-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 07/30/2017] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Replication timing experiments that use label incorporation and high throughput sequencing produce peaked data similar to ChIP-Seq experiments. However, the differences in experimental design, coverage density, and possible results make traditional ChIP-Seq analysis methods inappropriate for use with replication timing. RESULTS To accurately detect and classify regions of replication across the genome, we present Repliscan. Repliscan robustly normalizes, automatically removes outlying and uninformative data points, and classifies Repli-seq signals into discrete combinations of replication signatures. The quality control steps and self-fitting methods make Repliscan generally applicable and more robust than previous methods that classify regions based on thresholds. CONCLUSIONS Repliscan is simple and effective to use on organisms with different genome sizes. Even with analysis window sizes as small as 1 kilobase, reliable profiles can be generated with as little as 2.4x coverage.
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Affiliation(s)
- Gregory J Zynda
- Texas Advanced Computing Center, University of Texas at Austin, 10100 Burnet Road, Austin, 78758-4497, TX, USA
| | - Jawon Song
- Texas Advanced Computing Center, University of Texas at Austin, 10100 Burnet Road, Austin, 78758-4497, TX, USA
| | - Lorenzo Concia
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, 27695-7612, NC, USA
| | - Emily E Wear
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, 27695-7612, NC, USA
| | - Linda Hanley-Bowdoin
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, 27695-7612, NC, USA
| | - William F Thompson
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, 27695-7612, NC, USA
| | - Matthew W Vaughn
- Texas Advanced Computing Center, University of Texas at Austin, 10100 Burnet Road, Austin, 78758-4497, TX, USA.
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22
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Shima N, Pederson KD. Dormant origins as a built-in safeguard in eukaryotic DNA replication against genome instability and disease development. DNA Repair (Amst) 2017; 56:166-173. [PMID: 28641940 PMCID: PMC5547906 DOI: 10.1016/j.dnarep.2017.06.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
DNA replication is a prerequisite for cell proliferation, yet it can be increasingly challenging for a eukaryotic cell to faithfully duplicate its genome as its size and complexity expands. Dormant origins now emerge as a key component for cells to successfully accomplish such a demanding but essential task. In this perspective, we will first provide an overview of the fundamental processes eukaryotic cells have developed to regulate origin licensing and firing. With a special focus on mammalian systems, we will then highlight the role of dormant origins in preventing replication-associated genome instability and their functional interplay with proteins involved in the DNA damage repair response for tumor suppression. Lastly, deficiencies in the origin licensing machinery will be discussed in relation to their influence on stem cell maintenance and human diseases.
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Affiliation(s)
- Naoko Shima
- The University of Minnesota, Twin Cities, Department of Genetics, Cell Biology and Development, Masonic Cancer Center, 6-160 Jackson Hall, 321 Church St SE., Minneapolis, MN 55455, United States.
| | - Kayla D Pederson
- The University of Minnesota, Twin Cities, Department of Genetics, Cell Biology and Development, Masonic Cancer Center, 6-160 Jackson Hall, 321 Church St SE., Minneapolis, MN 55455, United States
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23
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Blumenfeld B, Ben-Zimra M, Simon I. Perturbations in the Replication Program Contribute to Genomic Instability in Cancer. Int J Mol Sci 2017; 18:E1138. [PMID: 28587102 PMCID: PMC5485962 DOI: 10.3390/ijms18061138] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/08/2017] [Accepted: 05/21/2017] [Indexed: 12/14/2022] Open
Abstract
Cancer and genomic instability are highly impacted by the deoxyribonucleic acid (DNA) replication program. Inaccuracies in DNA replication lead to the increased acquisition of mutations and structural variations. These inaccuracies mainly stem from loss of DNA fidelity due to replication stress or due to aberrations in the temporal organization of the replication process. Here we review the mechanisms and impact of these major sources of error to the replication program.
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Affiliation(s)
- Britny Blumenfeld
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel.
| | - Micha Ben-Zimra
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel.
- Pharmacology and Experimental Therapeutics Unit, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel.
| | - Itamar Simon
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel.
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24
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Anatomy of Mammalian Replication Domains. Genes (Basel) 2017; 8:genes8040110. [PMID: 28350365 PMCID: PMC5406857 DOI: 10.3390/genes8040110] [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: 12/08/2016] [Revised: 03/22/2017] [Accepted: 03/24/2017] [Indexed: 02/07/2023] Open
Abstract
Genetic information is faithfully copied by DNA replication through many rounds of cell division. In mammals, DNA is replicated in Mb-sized chromosomal units called “replication domains.” While genome-wide maps in multiple cell types and disease states have uncovered both dynamic and static properties of replication domains, we are still in the process of understanding the mechanisms that give rise to these properties. A better understanding of the molecular basis of replication domain regulation will bring new insights into chromosome structure and function.
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25
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Yehuda Y, Blumenfeld B, Lehmann D, Simon I. Genome-wide Determination of Mammalian Replication Timing by DNA Content Measurement. J Vis Exp 2017. [PMID: 28190030 DOI: 10.3791/55157] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Replication of the genome occurs during S phase of the cell cycle in a highly regulated process that ensures the fidelity of DNA duplication. Each genomic region is replicated at a distinct time during S phase through the simultaneous activation of multiple origins of replication. Time of replication (ToR) correlates with many genomic and epigenetic features and is linked to mutation rates and cancer. Comprehending the full genomic view of the replication program, in health and disease is a major future goal and challenge. This article describes in detail the "Copy Number Ratio of S/G1 for mapping genomic Time of Replication" method (herein called: CNR-ToR), a simple approach to map the genome wide ToR of mammalian cells. The method is based on the copy number differences between S phase cells and G1 phase cells. The CNR-ToR method is performed in 6 steps: 1. Preparation of cells and staining with propidium iodide (PI); 2. Sorting G1 and S phase cells using fluorescence-activated cell sorting (FACS); 3. DNA purification; 4. Sonication; 5. Library preparation and sequencing; and 6. Bioinformatic analysis. The CNR-ToR method is a fast and easy approach that results in detailed replication maps.
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Affiliation(s)
- Yishai Yehuda
- Dept. of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem
| | - Britny Blumenfeld
- Dept. of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem
| | - Dan Lehmann
- The Core Research Facility, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem
| | - Itamar Simon
- Dept. of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem;
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26
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Seplyarskiy VB, Andrianova MA, Bazykin GA. APOBEC3A/B-induced mutagenesis is responsible for 20% of heritable mutations in the TpCpW context. Genome Res 2016; 27:175-184. [PMID: 27940951 PMCID: PMC5287224 DOI: 10.1101/gr.210336.116] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 12/01/2016] [Indexed: 12/18/2022]
Abstract
APOBEC3A/B cytidine deaminase is responsible for the majority of cancerous mutations in a large fraction of cancer samples. However, its role in heritable mutagenesis remains very poorly understood. Recent studies have demonstrated that both in yeast and in human cancerous cells, most APOBEC3A/B-induced mutations occur on the lagging strand during replication and on the nontemplate strand of transcribed regions. Here, we use data on rare human polymorphisms, interspecies divergence, and de novo mutations to study germline mutagenesis and to analyze mutations at nucleotide contexts prone to attack by APOBEC3A/B. We show that such mutations occur preferentially on the lagging strand and on nontemplate strands of transcribed regions. Moreover, we demonstrate that APOBEC3A/B-like mutations tend to produce strand-coordinated clusters, which are also biased toward the lagging strand. Finally, we show that the mutation rate is increased 3' of C→G mutations to a greater extent than 3' of C→T mutations, suggesting pervasive trans-lesion bypass of the APOBEC3A/B-induced damage. Our study demonstrates that 20% of C→T and C→G mutations in the TpCpW context-where W denotes A or T, segregating as polymorphisms in human population-or 1.4% of all heritable mutations are attributable to APOBEC3A/B activity.
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Affiliation(s)
- Vladimir B Seplyarskiy
- Institute for Information Transmission Problems of the Russian Academy of Sciences (Kharkevich Institute), Moscow 127994, Russia.,Pirogov Russian National Research Medical University, Moscow 117997, Russia
| | - Maria A Andrianova
- Institute for Information Transmission Problems of the Russian Academy of Sciences (Kharkevich Institute), Moscow 127994, Russia.,Pirogov Russian National Research Medical University, Moscow 117997, Russia.,Lomonosov Moscow State University, Moscow 119234, Russia
| | - Georgii A Bazykin
- Institute for Information Transmission Problems of the Russian Academy of Sciences (Kharkevich Institute), Moscow 127994, Russia.,Pirogov Russian National Research Medical University, Moscow 117997, Russia.,Lomonosov Moscow State University, Moscow 119234, Russia.,Skolkovo Institute of Science and Technology, Skolkovo 143026, Russia
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27
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Feng W, Michaels SD. Accessing the Inaccessible: The Organization, Transcription, Replication, and Repair of Heterochromatin in Plants. Annu Rev Genet 2016; 49:439-59. [PMID: 26631514 DOI: 10.1146/annurev-genet-112414-055048] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Eukaryotic genomes often contain large quantities of potentially deleterious sequences, such as transposons. One strategy for mitigating this risk is to package such sequences into so-called constitutive heterochromatin, where the dense chromatin environment is thought to inhibit transcription by excluding transcription factors and RNA polymerase. This type of model makes it tempting to think of heterochromatin as an inert region that is isolated from the rest of the nucleus. Recent work on heterochromatin, however, reveals that it is a dynamic environment. Despite its dense packaging, heterochromatin must remain accessible for a host of processes, including DNA replication and repair, and, paradoxically, transcription. In plants, transcripts produced by specialized RNA polymerases are used to target regions of the genome for silencing via DNA methylation. Thus, the maintenance of heterochromatin requires a careful balancing act of access and exclusion, which is achieved through the action of a host of interrelated pathways.
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Affiliation(s)
- Wei Feng
- Carnegie Institution for Science, Department of Plant Biology, Stanford, California 94305;
| | - Scott D Michaels
- Department of Biology, Indiana University, Bloomington, Indiana 47405;
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28
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29
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Kenigsberg E, Yehuda Y, Marjavaara L, Keszthelyi A, Chabes A, Tanay A, Simon I. The mutation spectrum in genomic late replication domains shapes mammalian GC content. Nucleic Acids Res 2016; 44:4222-32. [PMID: 27085808 PMCID: PMC4872117 DOI: 10.1093/nar/gkw268] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 03/10/2016] [Accepted: 03/30/2016] [Indexed: 11/14/2022] Open
Abstract
Genome sequence compositions and epigenetic organizations are correlated extensively across multiple length scales. Replication dynamics, in particular, is highly correlated with GC content. We combine genome-wide time of replication (ToR) data, topological domains maps and detailed functional epigenetic annotations to study the correlations between replication timing and GC content at multiple scales. We find that the decrease in genomic GC content at large scale late replicating regions can be explained by mutation bias favoring A/T nucleotide, without selection or biased gene conversion. Quantification of the free dNTP pool during the cell cycle is consistent with a mechanism involving replication-coupled mutation spectrum that favors AT nucleotides at late S-phase. We suggest that mammalian GC content composition is shaped by independent forces, globally modulating mutation bias and locally selecting on functional element. Deconvoluting these forces and analyzing them on their native scales is important for proper characterization of complex genomic correlations.
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Affiliation(s)
- Ephraim Kenigsberg
- Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel
| | - Yishai Yehuda
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Lisette Marjavaara
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Andrea Keszthelyi
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Amos Tanay
- Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel
| | - Itamar Simon
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
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30
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Almouzni G, Cedar H. Maintenance of Epigenetic Information. Cold Spring Harb Perspect Biol 2016; 8:8/5/a019372. [PMID: 27141050 DOI: 10.1101/cshperspect.a019372] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The genome is subject to a diverse array of epigenetic modifications from DNA methylation to histone posttranslational changes. Many of these marks are somatically stable through cell division. This article focuses on our knowledge of the mechanisms governing the inheritance of epigenetic marks, particularly, repressive ones, when the DNA and chromatin template are duplicated in S phase. This involves the action of histone chaperones, nucleosome-remodeling enzymes, histone and DNA methylation binding proteins, and chromatin-modifying enzymes. Last, the timing of DNA replication is discussed, including the question of whether this constitutes an epigenetic mark that facilitates the propagation of epigenetic marks.
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Affiliation(s)
- Geneviève Almouzni
- Department of Nuclear Dynamics and Genome Plasticity, Institut Curie, Section de recherche, 75231 Paris Cedex 05, France
| | - Howard Cedar
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University Medical School, Ein Kerem, Jerusalem, Israel 91120
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31
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Seplyarskiy VB, Soldatov RA, Popadin KY, Antonarakis SE, Bazykin GA, Nikolaev SI. APOBEC-induced mutations in human cancers are strongly enriched on the lagging DNA strand during replication. Genome Res 2016; 26:174-82. [PMID: 26755635 PMCID: PMC4728370 DOI: 10.1101/gr.197046.115] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/10/2015] [Indexed: 12/31/2022]
Abstract
APOBEC3A and APOBEC3B, cytidine deaminases of the APOBEC family, are among the main factors causing mutations in human cancers. APOBEC deaminates cytosines in single-stranded DNA (ssDNA). A fraction of the APOBEC-induced mutations occur as clusters ("kataegis") in single-stranded DNA produced during repair of double-stranded breaks (DSBs). However, the properties of the remaining 87% of nonclustered APOBEC-induced mutations, the source and the genomic distribution of the ssDNA where they occur, are largely unknown. By analyzing genomic and exomic cancer databases, we show that >33% of dispersed APOBEC-induced mutations occur on the lagging strand during DNA replication, thus unraveling the major source of ssDNA targeted by APOBEC in cancer. Although methylated cytosine is generally more mutation-prone than nonmethylated cytosine, we report that methylation reduces the rate of APOBEC-induced mutations by a factor of roughly two. Finally, we show that in cancers with extensive APOBEC-induced mutagenesis, there is almost no increase in mutation rates in late replicating regions (contrary to other cancers). Because late-replicating regions are depleted in exons, this results in a 1.3-fold higher fraction of mutations residing within exons in such cancers. This study provides novel insight into the APOBEC-induced mutagenesis and describes the peculiarity of the mutational processes in cancers with the signature of APOBEC-induced mutations.
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Affiliation(s)
- Vladimir B Seplyarskiy
- Institute of Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia, 127051; Lomonosov Moscow State University, Moscow, Russia, 119991; Pirogov Russian National Research Medical University, Moscow, Russia, 117997
| | - Ruslan A Soldatov
- Institute of Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia, 127051; Lomonosov Moscow State University, Moscow, Russia, 119991
| | - Konstantin Y Popadin
- Department of Genetic Medicine and Development, University of Geneva Medical School, 1211 Geneva, Switzerland; Institute of Genetics and Genomics in Geneva, 1211 Geneva, Switzerland
| | - Stylianos E Antonarakis
- Department of Genetic Medicine and Development, University of Geneva Medical School, 1211 Geneva, Switzerland; Institute of Genetics and Genomics in Geneva, 1211 Geneva, Switzerland
| | - Georgii A Bazykin
- Institute of Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia, 127051; Lomonosov Moscow State University, Moscow, Russia, 119991; Pirogov Russian National Research Medical University, Moscow, Russia, 117997
| | - Sergey I Nikolaev
- Department of Genetic Medicine and Development, University of Geneva Medical School, 1211 Geneva, Switzerland; Institute of Genetics and Genomics in Geneva, 1211 Geneva, Switzerland; Service of Genetic Medicine, University Hospitals of Geneva, 1211 Geneva, Switzerland
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32
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Dileep V, Rivera-Mulia JC, Sima J, Gilbert DM. Large-Scale Chromatin Structure-Function Relationships during the Cell Cycle and Development: Insights from Replication Timing. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2015; 80:53-63. [PMID: 26590169 DOI: 10.1101/sqb.2015.80.027284] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Chromosome architecture has received a lot of attention since the recent development of genome-scale methods to measure chromatin interactions (Hi-C), enabling the first sequence-based models of chromosome tertiary structure. A view has emerged of chromosomes as a string of structural units (topologically associating domains; TADs) whose boundaries persist through the cell cycle and development. TADs with similar chromatin states tend to aggregate, forming spatially segregated chromatin compartments. However, high-resolution Hi-C has revealed substructure within TADs (subTADs) that poses a challenge for models that attribute significance to structural units at any given scale. More than 20 years ago, the DNA replication field independently identified stable structural (and functional) units of chromosomes (replication foci) as well as spatially segregated chromatin compartments (early and late foci), but lacked the means to link these units to genomic map units. Genome-wide studies of replication timing (RT) have now merged these two disciplines by identifying individual units of replication regulation (replication domains; RDs) that correspond to TADs and are arranged in 3D to form spatiotemporally segregated subnuclear compartments. Furthermore, classifying RDs/TADs by their constitutive versus developmentally regulated RT has revealed distinct classes of chromatin organization, providing unexpected insight into the relationship between large-scale chromosome structure and function.
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Affiliation(s)
- Vishnu Dileep
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295
| | | | - Jiao Sima
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295
| | - David M Gilbert
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295 Center for Genomics and Personalized Medicine, Florida State University, Tallahassee, Florida 32306-4295
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33
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Liu F, Ren C, Li H, Zhou P, Bo X, Shu W. De novo identification of replication-timing domains in the human genome by deep learning. Bioinformatics 2015; 32:641-9. [PMID: 26545821 PMCID: PMC4795613 DOI: 10.1093/bioinformatics/btv643] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 10/27/2015] [Indexed: 12/31/2022] Open
Abstract
Motivation: The de novo identification of the initiation and termination zones—regions that replicate earlier or later than their upstream and downstream neighbours, respectively—remains a key challenge in DNA replication. Results: Building on advances in deep learning, we developed a novel hybrid architecture combining a pre-trained, deep neural network and a hidden Markov model (DNN-HMM) for the de novo identification of replication domains using replication timing profiles. Our results demonstrate that DNN-HMM can significantly outperform strong, discriminatively trained Gaussian mixture model–HMM (GMM-HMM) systems and other six reported methods that can be applied to this challenge. We applied our trained DNN-HMM to identify distinct replication domain types, namely the early replication domain (ERD), the down transition zone (DTZ), the late replication domain (LRD) and the up transition zone (UTZ), using newly replicated DNA sequencing (Repli-Seq) data across 15 human cells. A subsequent integrative analysis revealed that these replication domains harbour unique genomic and epigenetic patterns, transcriptional activity and higher-order chromosomal structure. Our findings support the ‘replication-domain’ model, which states (1) that ERDs and LRDs, connected by UTZs and DTZs, are spatially compartmentalized structural and functional units of higher-order chromosomal structure, (2) that the adjacent DTZ-UTZ pairs form chromatin loops and (3) that intra-interactions within ERDs and LRDs tend to be short-range and long-range, respectively. Our model reveals an important chromatin organizational principle of the human genome and represents a critical step towards understanding the mechanisms regulating replication timing. Availability and implementation: Our DNN-HMM method and three additional algorithms can be freely accessed at https://github.com/wenjiegroup/DNN-HMM. The replication domain regions identified in this study are available in GEO under the accession ID GSE53984. Contact:shuwj@bmi.ac.cn or boxc@bmi.ac.cn Supplementary information:Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Feng Liu
- Department of Biotechnology, Beijing Institute of Radiation Medicine and
| | - Chao Ren
- Department of Biotechnology, Beijing Institute of Radiation Medicine and
| | - Hao Li
- Department of Biotechnology, Beijing Institute of Radiation Medicine and
| | - Pingkun Zhou
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Xiaochen Bo
- Department of Biotechnology, Beijing Institute of Radiation Medicine and
| | - Wenjie Shu
- Department of Biotechnology, Beijing Institute of Radiation Medicine and
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34
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Nassar D, Latil M, Boeckx B, Lambrechts D, Blanpain C. Genomic landscape of carcinogen-induced and genetically induced mouse skin squamous cell carcinoma. Nat Med 2015; 21:946-54. [PMID: 26168291 DOI: 10.1038/nm.3878] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 05/18/2015] [Indexed: 12/17/2022]
Abstract
Mouse models of cancers are routinely used to study cancer biology. However, it remains unclear whether carcinogenesis in mice is driven by the same spectrum of genomic alterations found in humans. Here we conducted a comprehensive genomic analysis of 9,10-dimethyl-1,2-benzanthracene (DMBA)-induced skin cancer, the most commonly used skin cancer model, which appears as benign papillomas that progress into squamous cell carcinomas (SCCs). We also studied genetically induced SCCs that expressed G12D mutant Kras (Kras G12D) but were deficient for p53. Using whole-exome sequencing, we uncovered a characteristic mutational signature of DMBA-induced SCCs. We found that the vast majority of DMBA-induced SCCs presented recurrent mutations in Hras, Kras or Rras2 and mutations in several additional putative oncogenes and tumor-suppressor genes. Similar genes were recurrently mutated in mouse and human SCCs that were from different organs or had been exposed to different carcinogens. Invasive SCCs, but not papillomas, presented substantial chromosomal aberrations, especially in DMBA-induced and genetically induced Trp53-mutated SCCs. Metastasis occurred through sequential spreading, with relatively few additional genetic events. This study provides a framework for future functional cancer genomic studies in mice.
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Affiliation(s)
- Dany Nassar
- Institut de recherche interdisciplinaire en biologie humaine et moléculaire (IRIBHM), Université libre de Buxelles (ULB), Brussels, Belgium
| | - Mathilde Latil
- Institut de recherche interdisciplinaire en biologie humaine et moléculaire (IRIBHM), Université libre de Buxelles (ULB), Brussels, Belgium
| | - Bram Boeckx
- 1] Vesalius Research Center, Vlaams Instituut voor Biotechnologie VIB, Leuven, Belgium. [2] Laboratory for Translational Genetics, Department of Oncology, Katholieke Universiteit Leuven (KUL), Leuven, Belgium
| | - Diether Lambrechts
- 1] Vesalius Research Center, Vlaams Instituut voor Biotechnologie VIB, Leuven, Belgium. [2] Laboratory for Translational Genetics, Department of Oncology, Katholieke Universiteit Leuven (KUL), Leuven, Belgium
| | - Cédric Blanpain
- 1] Institut de recherche interdisciplinaire en biologie humaine et moléculaire (IRIBHM), Université libre de Buxelles (ULB), Brussels, Belgium. [2] WELBIO, Brussels, Belgium
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35
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Rivera-Mulia JC, Buckley Q, Sasaki T, Zimmerman J, Didier RA, Nazor K, Loring JF, Lian Z, Weissman S, Robins AJ, Schulz TC, Menendez L, Kulik MJ, Dalton S, Gabr H, Kahveci T, Gilbert DM. Dynamic changes in replication timing and gene expression during lineage specification of human pluripotent stem cells. Genome Res 2015; 25:1091-103. [PMID: 26055160 PMCID: PMC4509994 DOI: 10.1101/gr.187989.114] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 06/05/2015] [Indexed: 12/31/2022]
Abstract
Duplication of the genome in mammalian cells occurs in a defined temporal order referred to as its replication-timing (RT) program. RT changes dynamically during development, regulated in units of 400-800 kb referred to as replication domains (RDs). Changes in RT are generally coordinated with transcriptional competence and changes in subnuclear position. We generated genome-wide RT profiles for 26 distinct human cell types, including embryonic stem cell (hESC)-derived, primary cells and established cell lines representing intermediate stages of endoderm, mesoderm, ectoderm, and neural crest (NC) development. We identified clusters of RDs that replicate at unique times in each stage (RT signatures) and confirmed global consolidation of the genome into larger synchronously replicating segments during differentiation. Surprisingly, transcriptome data revealed that the well-accepted correlation between early replication and transcriptional activity was restricted to RT-constitutive genes, whereas two-thirds of the genes that switched RT during differentiation were strongly expressed when late replicating in one or more cell types. Closer inspection revealed that transcription of this class of genes was frequently restricted to the lineage in which the RT switch occurred, but was induced prior to a late-to-early RT switch and/or down-regulated after an early-to-late RT switch. Analysis of transcriptional regulatory networks showed that this class of genes contains strong regulators of genes that were only expressed when early replicating. These results provide intriguing new insight into the complex relationship between transcription and RT regulation during human development.
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Affiliation(s)
- Juan Carlos Rivera-Mulia
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295, USA
| | - Quinton Buckley
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295, USA
| | - Takayo Sasaki
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295, USA
| | - Jared Zimmerman
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295, USA
| | - Ruth A Didier
- College of Medicine, Florida State University, Tallahassee, Florida 32306-4295, USA
| | - Kristopher Nazor
- Center for Regenerative Medicine, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Jeanne F Loring
- Center for Regenerative Medicine, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Zheng Lian
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06519, USA
| | - Sherman Weissman
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06519, USA
| | | | | | - Laura Menendez
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, USA
| | - Michael J Kulik
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, USA
| | - Stephen Dalton
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, USA
| | - Haitham Gabr
- Department of Computer and Information Sciences and Engineering, University of Florida, Gainesville, Florida 32611, USA
| | - Tamer Kahveci
- Department of Computer and Information Sciences and Engineering, University of Florida, Gainesville, Florida 32611, USA
| | - David M Gilbert
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295, USA; Center for Genomics and Personalized Medicine, Florida State University, Tallahassee, Florida 32306, USA
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36
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Bartholdy B, Mukhopadhyay R, Lajugie J, Aladjem MI, Bouhassira EE. Allele-specific analysis of DNA replication origins in mammalian cells. Nat Commun 2015; 6:7051. [PMID: 25987481 PMCID: PMC4479011 DOI: 10.1038/ncomms8051] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 03/26/2015] [Indexed: 01/01/2023] Open
Abstract
The mechanisms that control the location and timing of firing of replication origins are poorly understood. Using a novel functional genomic approach based on the analysis of SNPs and indels in phased human genomes, we observe that replication asynchrony is associated with small cumulative variations in the initiation efficiency of multiple origins between the chromosome homologues, rather than with the activation of dormant origins. Allele-specific measurements demonstrate that the presence of G-quadruplex-forming sequences does not correlate with the efficiency of initiation. Sequence analysis reveals that the origins are highly enriched in sequences with profoundly asymmetric G/C and A/T nucleotide distributions and are almost completely depleted of antiparallel triplex-forming sequences. We therefore propose that although G4-forming sequences are abundant in replication origins, an asymmetry in nucleotide distribution, which increases the propensity of origins to unwind and adopt non-B DNA structure, rather than the ability to form G4, is directly associated with origin activity.
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Affiliation(s)
- Boris Bartholdy
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
| | - Rituparna Mukhopadhyay
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
| | - Julien Lajugie
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
| | - Mirit I. Aladjem
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 37 Convent Drive, Bethesda, Maryland 20892, USA
| | - Eric E. Bouhassira
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
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37
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Boulos RE, Drillon G, Argoul F, Arneodo A, Audit B. Structural organization of human replication timing domains. FEBS Lett 2015; 589:2944-57. [PMID: 25912651 DOI: 10.1016/j.febslet.2015.04.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 04/09/2015] [Accepted: 04/10/2015] [Indexed: 12/16/2022]
Abstract
Recent analysis of genome-wide epigenetic modification data, mean replication timing (MRT) profiles and chromosome conformation data in mammals have provided increasing evidence that flexibility in replication origin usage is regulated locally by the epigenetic landscape and over larger genomic distances by the 3D chromatin architecture. Here, we review the recent results establishing some link between replication domains and chromatin structural domains in pluripotent and various differentiated cell types in human. We reconcile the originally proposed dichotomic picture of early and late constant timing regions that replicate by multiple rather synchronous origins in separated nuclear compartments of open and closed chromatins, with the U-shaped MRT domains bordered by "master" replication origins specified by a localized (∼200-300 kb) zone of open and transcriptionally active chromatin from which a replication wave likely initiates and propagates toward the domain center via a cascade of origin firing. We discuss the relationships between these MRT domains, topologically associated domains and lamina-associated domains. This review sheds a new light on the epigenetically regulated global chromatin reorganization that underlies the loss of pluripotency and the determination of differentiation properties.
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Affiliation(s)
- Rasha E Boulos
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France
| | - Guénola Drillon
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France
| | - Françoise Argoul
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France
| | - Alain Arneodo
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France
| | - Benjamin Audit
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France.
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38
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Unique features of mutations revealed by sequentially reprogrammed induced pluripotent stem cells. Nat Commun 2015; 6:6318. [PMID: 25692725 DOI: 10.1038/ncomms7318] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 01/16/2015] [Indexed: 01/06/2023] Open
Abstract
Although viable mice can be generated from induced pluripotent stem cells (iPSCs), the impact of accumulated mutations on the developmental potential of the resulting iPSCs remains to be determined. Here, we demonstrate that all-iPSC mice generated through tetraploid blastocysts complementation can tolerate the accumulation of somatic mutations for up to six generations using a Tet-on inducible reprogramming system. But, the viability of the all-iPS mice decreased with increasing generations. A whole-genome sequencing survey revealed that thousands of single-nucleotide variations (SNVs), including 44 non-synonymous ones, accumulated throughout the sequential reprogramming process. Subsequent analysis provides evidence that these accumulated SNVs account for the gradual reduction in viability of the resultant all-iPSC mice. Unexpectedly, our present reprogramming system revealed that pluripotent stem cells are heterogeneous in terms of possessing a set of copy-number alterations (CNAs). These CNAs are unique for pluripotent cells and subsequently disappear in the differentiating progenies.
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39
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Embryonic stem cell specific "master" replication origins at the heart of the loss of pluripotency. PLoS Comput Biol 2015; 11:e1003969. [PMID: 25658386 PMCID: PMC4319821 DOI: 10.1371/journal.pcbi.1003969] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 10/06/2014] [Indexed: 11/29/2022] Open
Abstract
Epigenetic regulation of the replication program during mammalian cell differentiation remains poorly understood. We performed an integrative analysis of eleven genome-wide epigenetic profiles at 100 kb resolution of Mean Replication Timing (MRT) data in six human cell lines. Compared to the organization in four chromatin states shared by the five somatic cell lines, embryonic stem cell (ESC) line H1 displays (i) a gene-poor but highly dynamic chromatin state (EC4) associated to histone variant H2AZ rather than a HP1-associated heterochromatin state (C4) and (ii) a mid-S accessible chromatin state with bivalent gene marks instead of a polycomb-repressed heterochromatin state. Plastic MRT regions (≲ 20% of the genome) are predominantly localized at the borders of U-shaped timing domains. Whereas somatic-specific U-domain borders are gene-dense GC-rich regions, 31.6% of H1-specific U-domain borders are early EC4 regions enriched in pluripotency transcription factors NANOG and OCT4 despite being GC poor and gene deserts. Silencing of these ESC-specific “master” replication initiation zones during differentiation corresponds to a loss of H2AZ and an enrichment in H3K9me3 mark characteristic of late replicating C4 heterochromatin. These results shed a new light on the epigenetically regulated global chromatin reorganization that underlies the loss of pluripotency and lineage commitment. During development, embryonic stem cell (ESC) enter a program of cell differentiation eventually leading to all the necessary differentiated cell types. Understanding the mechanisms responsible for the underlying modifications of the gene expression program is of fundamental importance, as it will likely have strong impact on the development of regenerative medicine. We show that besides some epigenetic regulation, ubiquitous master replication origins at replication timing U-domain borders shared by 6 human cell types are transcriptionally active open chromatin regions specified by a local enrichment in nucleosome free regions encoded in the DNA sequence suggesting that they have been selected during evolution. In contrast, ESC specific master replication origins bear a unique epigenetic signature (enrichment in CTCF, H2AZ, NANOG, OCT4, …) likely contributing to maintain ESC chromatin in a highly dynamic and accessible state that is refractory to polycomb and HP1 heterochromatin spreading. These ESC specific master origins thus appear as key genomic regions where epigenetic control of chromatin organization is at play to maintain pluripotency of stem cell lineages and to guide lineage commitment to somatic cell types.
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Dellino GI, Pelicci PG. Next-generation sequencing and DNA replication in human cells: the future has arrived. Future Oncol 2015; 10:683-93. [PMID: 24754597 DOI: 10.2217/fon.13.182] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Accurate regulation of DNA replication ensures faithful transmission of eukaryotic genomes and maintenance of genomic stability and chromatin organization. However, by itself the replication process is a threat for both DNA and chromatin integrity. This becomes particularly relevant in cancer cells, where activated oncogenes induce replication-stress, including unscheduled initiation, fork stalling and collapse and, ultimately, genomic instability. Studies addressing the relationship between (epi)genome integrity and disease have been hampered by our poor knowledge of the mechanisms regulating where and when eukaryotic replication initiates. Recently developed genome-scale methods for the analysis of DNA replication in mammals will contribute to the identification of missing links between replication, chromatin regulation and genome stability in normal and cancer cells.
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Affiliation(s)
- Gaetano Ivan Dellino
- Department of Experimental Oncology, European Institute of Oncology, 20141 Milan, Italy
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Chen L, Zhou W, Zhang L, Zhang F. Genome architecture and its roles in human copy number variation. Genomics Inform 2014; 12:136-44. [PMID: 25705150 PMCID: PMC4330246 DOI: 10.5808/gi.2014.12.4.136] [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: 10/13/2014] [Revised: 11/12/2014] [Accepted: 11/12/2014] [Indexed: 02/06/2023] Open
Abstract
Besides single-nucleotide variants in the human genome, large-scale genomic variants, such as copy number variations (CNVs), are being increasingly discovered as a genetic source of human diversity and the pathogenic factors of diseases. Recent experimental findings have shed light on the links between different genome architectures and CNV mutagenesis. In this review, we summarize various genomic features and discuss their contributions to CNV formation. Genomic repeats, including both low-copy and high-copy repeats, play important roles in CNV instability, which was initially known as DNA recombination events. Furthermore, it has been found that human genomic repeats can also induce DNA replication errors and consequently result in CNV mutations. Some recent studies showed that DNA replication timing, which reflects the high-order information of genomic organization, is involved in human CNV mutations. Our review highlights that genome architecture, from DNA sequence to high-order genomic organization, is an important molecular factor in CNV mutagenesis and human genomic instability.
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Affiliation(s)
- Lu Chen
- School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Weichen Zhou
- School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Ling Zhang
- School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Feng Zhang
- School of Life Sciences, Fudan University, Shanghai 200438, China. ; Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai 200438, China
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Levin-Klein R, Bergman Y. Epigenetic regulation of monoallelic rearrangement (allelic exclusion) of antigen receptor genes. Front Immunol 2014; 5:625. [PMID: 25538709 PMCID: PMC4257082 DOI: 10.3389/fimmu.2014.00625] [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: 09/17/2014] [Accepted: 11/22/2014] [Indexed: 12/31/2022] Open
Abstract
While most genes in the mammalian genome are transcribed from both parental chromosomes in cells where they are expressed, approximately 10% of genes are expressed monoallelically, so that any given cell will express either the paternal or maternal allele, but not both. The antigen receptor genes in B and T cells are well-studied examples of a gene family, which is expressed in a monoallelic manner, in a process coined "allelic exclusion." During lymphocyte development, only one allele of each antigen receptor undergoes V(D)J rearrangement at a time, and once productive rearrangement is sensed, rearrangement of the second allele is prevented. In this mini review, we discuss the epigenetic processes, including asynchronous replication, nuclear localization, chromatin condensation, histone modifications, and DNA methylation, which appear to regulate the primary rearrangement of a single allele, while blocking the rearrangement of the second allele.
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Affiliation(s)
- Rena Levin-Klein
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel Canada, Hebrew University Medical School , Jerusalem , Israel
| | - Yehudit Bergman
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel Canada, Hebrew University Medical School , Jerusalem , Israel
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Gispan A, Carmi M, Barkai N. Checkpoint-independent scaling of the Saccharomyces cerevisiae DNA replication program. BMC Biol 2014; 12:79. [PMID: 25288172 PMCID: PMC4218987 DOI: 10.1186/s12915-014-0079-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 09/18/2014] [Indexed: 12/22/2022] Open
Abstract
Background In budding yeast, perturbations that prolong S phase lead to a proportionate delay in the activation times of most origins. The DNA replication checkpoint was implicated in this scaling phenotype, as an intact checkpoint was shown to be required for the delayed activation of late origins in response to hydroxyurea treatment. In support of that, scaling is lost in cells deleted of mrc1, a mediator of the replication checkpoint signal. Mrc1p, however, also plays a role in normal replication. Results To examine whether the replication checkpoint is required for scaling the replication profile with S phase duration we measured the genome-wide replication profile of different MRC1 alleles that separate its checkpoint function from its role in normal replication, and further analyzed the replication profiles of S phase mutants that are checkpoint deficient. We found that the checkpoint is not required for scaling; rather the unique replication phenotype of mrc1 deleted cells is attributed to the role of Mrc1 in normal replication. This is further supported by the replication profiles of tof1Δ which functions together with Mrc1p in normal replication, and by the distinct replication profiles of specific POL2 alleles which differ in their interaction with Mrc1p. Conclusions We suggest that the slow fork progression in mrc1 deleted cells reduces the likelihood of passive replication leading to the activation of origins that remain mostly dormant in wild-type cells. Electronic supplementary material The online version of this article (doi:10.1186/s12915-014-0079-z) contains supplementary material, which is available to authorized users.
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Barlow JH, Nussenzweig A. Replication initiation and genome instability: a crossroads for DNA and RNA synthesis. Cell Mol Life Sci 2014; 71:4545-59. [PMID: 25238783 DOI: 10.1007/s00018-014-1721-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 08/28/2014] [Indexed: 12/16/2022]
Abstract
Nuclear DNA replication requires the concerted action of hundreds of proteins to efficiently unwind and duplicate the entire genome while also retaining epigenetic regulatory information. Initiation of DNA replication is tightly regulated, rapidly firing thousands of origins once the conditions to promote rapid and faithful replication are in place, and defects in replication initiation lead to proliferation defects, genome instability, and a range of developmental abnormalities. Interestingly, DNA replication in metazoans initiates in actively transcribed DNA, meaning that replication initiation occurs in DNA that is co-occupied with tens of thousands of poised and active RNA polymerase complexes. Active transcription can induce genome instability, particularly during DNA replication, as RNA polymerases can induce torsional stress, formation of secondary structures, and act as a physical barrier to other enzymes involved in DNA metabolism. Here we discuss the challenges facing mammalian DNA replication, their impact on genome instability, and the development of cancer.
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Fraser HB. Cell-cycle regulated transcription associates with DNA replication timing in yeast and human. Genome Biol 2014; 14:R111. [PMID: 24098959 PMCID: PMC3983658 DOI: 10.1186/gb-2013-14-10-r111] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 09/20/2013] [Indexed: 11/25/2022] Open
Abstract
Background Eukaryotic DNA replication follows a specific temporal program, with some genomic regions consistently replicating earlier than others, yet what determines this program is largely unknown. Highly transcribed regions have been observed to replicate in early S-phase in all plant and animal species studied to date, but this relationship is thought to be absent from both budding yeast and fission yeast. No association between cell-cycle regulated transcription and replication timing has been reported for any species. Results Here I show that in budding yeast, fission yeast, and human, the genes most highly transcribed during S-phase replicate early, whereas those repressed in S-phase replicate late. Transcription during other cell-cycle phases shows either the opposite correlation with replication timing, or no relation. The relationship is strongest near late-firing origins of replication, which is not consistent with a previously proposed model—that replication timing may affect transcription—and instead suggests a potential mechanism involving the recruitment of limiting replication initiation factors during S-phase. Conclusions These results suggest that S-phase transcription may be an important determinant of DNA replication timing across eukaryotes, which may explain the well-established association between transcription and replication timing.
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Besnard E, Desprat R, Ryan M, Kahli M, Aladjem MI, Lemaitre JM. Best practices for mapping replication origins in eukaryotic chromosomes. ACTA ACUST UNITED AC 2014; 64:22.18.1-13. [PMID: 25181303 DOI: 10.1002/0471143030.cb2218s64] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Understanding the regulatory principles ensuring complete DNA replication in each cell division is critical for deciphering the mechanisms that maintain genomic stability. Recent advances in genome sequencing technology facilitated complete mapping of DNA replication sites and helped move the field from observing replication patterns at a handful of single loci to analyzing replication patterns genome-wide. These advances address issues, such as the relationship between replication initiation events, transcription, and chromatin modifications, and identify potential replication origin consensus sequences. This unit summarizes the technological and fundamental aspects of replication profiling and briefly discusses novel insights emerging from mining large datasets, published in the last 3 years, and also describes DNA replication dynamics on a whole-genome scale.
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Affiliation(s)
- Emilie Besnard
- Laboratory of Genome Plasticity and Aging, Institute of Functional Genomics, CNRS UMR5203, INSERM U661, UMI, Montpellier, France
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Zaghloul L, Drillon G, Boulos RE, Argoul F, Thermes C, Arneodo A, Audit B. Large replication skew domains delimit GC-poor gene deserts in human. Comput Biol Chem 2014; 53 Pt A:153-65. [PMID: 25224847 DOI: 10.1016/j.compbiolchem.2014.08.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2014] [Indexed: 01/25/2023]
Abstract
Besides their large-scale organization in isochores, mammalian genomes display megabase-sized regions, spanning both genes and intergenes, where the strand nucleotide composition asymmetry decreases linearly, possibly due to replication activity. These so-called skew-N domains cover about a third of the human genome and are bordered by two skew upward jumps that were hypothesized to compose a subset of "master" replication origins active in the germline. Skew-N domains were shown to exhibit a particular gene organization. Genes with CpG-rich promoters likely expressed in the germline are over represented near the master replication origins, with large genes being co-oriented with replication fork progression, which suggests some coordination of replication and transcription. In this study, we describe another skew structure that covers ∼13% of the human genome and that is bordered by putative master replication origins similar to the ones flanking skew-N domains. These skew-split-N domains have a shape reminiscent of a N, but split in half, leaving in the center a region of null skew whose length increases with domain size. These central regions (median size ∼860 kb) have a homogeneous composition, i.e. both a null and constant skew and a constant and low GC content. They correspond to heterochromatin gene deserts found in low-GC isochores with an average gene density of 0.81 promoters/Mb as compared to 7.73 promoters/Mb genome wide. The analysis of epigenetic marks and replication timing data confirms that, in these late replicating heterochomatic regions, the initiation of replication is likely to be random. This contrasts with the transcriptionally active euchromatin state found around the bordering well positioned master replication origins. Altogether skew-N domains and skew-split-N domains cover about 50% of the human genome.
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Affiliation(s)
- Lamia Zaghloul
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR 5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France
| | - Guénola Drillon
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR 5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France
| | - Rasha E Boulos
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR 5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France
| | - Françoise Argoul
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR 5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France
| | - Claude Thermes
- Centre de Génétique Moléculaire, CNRS UPR 3404, Gif-sur-Yvette, France
| | - Alain Arneodo
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR 5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France
| | - Benjamin Audit
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR 5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France.
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Liddle P, Lafon-Hughes L, Di Tomaso MV, Reyes-Ábalos AL, Jara J, Cerda M, Härtel S, Folle GA. Bleomycin-induced γH2AX foci map preferentially to replicating domains in CHO9 interphase nuclei. Chromosome Res 2014; 22:463-81. [DOI: 10.1007/s10577-014-9433-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 06/11/2014] [Accepted: 06/16/2014] [Indexed: 12/28/2022]
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Mukhopadhyay R, Lajugie J, Fourel N, Selzer A, Schizas M, Bartholdy B, Mar J, Lin CM, Martin MM, Ryan M, Aladjem MI, Bouhassira EE. Allele-specific genome-wide profiling in human primary erythroblasts reveal replication program organization. PLoS Genet 2014; 10:e1004319. [PMID: 24787348 PMCID: PMC4006724 DOI: 10.1371/journal.pgen.1004319] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 03/10/2014] [Indexed: 11/19/2022] Open
Abstract
We have developed a new approach to characterize allele-specific timing of DNA replication genome-wide in human primary basophilic erythroblasts. We show that the two chromosome homologs replicate at the same time in about 88% of the genome and that large structural variants are preferentially associated with asynchronous replication. We identified about 600 megabase-sized asynchronously replicated domains in two tested individuals. The longest asynchronously replicated domains are enriched in imprinted genes suggesting that structural variants and parental imprinting are two causes of replication asynchrony in the human genome. Biased chromosome X inactivation in one of the two individuals tested was another source of detectable replication asynchrony. Analysis of high-resolution TimEX profiles revealed small variations termed timing ripples, which were undetected in previous, lower resolution analyses. Timing ripples reflect highly reproducible, variations of the timing of replication in the 100 kb-range that exist within the well-characterized megabase-sized replication timing domains. These ripples correspond to clusters of origins of replication that we detected using novel nascent strands DNA profiling methods. Analysis of the distribution of replication origins revealed dramatic differences in initiation of replication frequencies during S phase and a strong association, in both synchronous and asynchronous regions, between origins of replication and three genomic features: G-quadruplexes, CpG Islands and transcription start sites. The frequency of initiation in asynchronous regions was similar in the two homologs. Asynchronous regions were richer in origins of replication than synchronous regions. DNA replication in mammalian cells proceeds according to a distinct order. Genes that are expressed tend to replicate before genes that are not expressed. We report here that we have developed a method to measure the timing of replication of the maternal and paternal chromosomes separately. We found that the paternal and maternal chromosomes replicate at exactly the same time in the large majority of the genome and that the 12% of the genome that replicated asynchronously was enriched in imprinted genes and in structural variants. Previous experiments have shown that chromosomes could be divided into replication timing domains that are a few hundred thousand to a few megabases in size. We show here that these domains can be divided into sub-domains defined by ripples in the timing profile. These ripples corresponded to clusters of origins of replication. Finally, we show that the frequency of initiation in asynchronous regions was similar in the two homologs.
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Affiliation(s)
- Rituparna Mukhopadhyay
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Julien Lajugie
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Nicolas Fourel
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Ari Selzer
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Michael Schizas
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Boris Bartholdy
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Jessica Mar
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Chii Mei Lin
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Melvenia M. Martin
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Michael Ryan
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Mirit I. Aladjem
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Eric E. Bouhassira
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail:
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Tian Y, Liu G, Wu C, Rong G, Sun A. Spring: A Method for Identifying Differentially Expressed Genes in Microarray Data. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.5504/bbeq.2013.0083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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