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Corazzi L, Ionasz V, Andrejev S, Wang LC, Vouzas A, Giaisi M, Di Muzio G, Ding B, Marx AJM, Henkenjohann J, Allers MM, Gilbert DM, Wei PC. Linear Interaction Between Replication and Transcription Shapes DNA Break Dynamics at Recurrent DNA Break Clusters. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.22.554340. [PMID: 37662334 PMCID: PMC10473677 DOI: 10.1101/2023.08.22.554340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Recurrent DNA break clusters (RDCs) are replication-transcription collision hotspots; many are unique to neural progenitor cells. Through high-resolution replication sequencing and a capture-ligation assay in mouse neural progenitor cells experiencing replication stress, we unraveled the replication features dictating RDC location and orientation. Most RDCs occur at the replication forks traversing timing transition regions (TTRs), where sparse replication origins connect unidirectional forks. Leftward-moving forks generate telomere-connected DNA double-strand breaks (DSBs), while rightward-moving forks lead to centromere-connected DSBs. Strand-specific mapping for DNA-bound RNA revealed co-transcriptional dual-strand DNA:RNA hybrids present at a higher density in RDC than in other actively transcribed long genes. In addition, mapping RNA polymerase activity revealed that head-to-head interactions between replication and transcription machinery resulted in 60% DSB contribution to the head-on compared to 40% for co-directional. Our findings revealed TTR as a novel fragile class and highlighted how the linear interaction between transcription and replication impacts genome stability.
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2
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Coelho DR, Palma FR, Paviani V, He C, Danes JM, Huang Y, Calado JCP, Hart PC, Furdui CM, Poole LB, Schipma MJ, Bonini MG. Nuclear-localized, iron-bound superoxide dismutase-2 antagonizes epithelial lineage programs to promote stemness of breast cancer cells via a histone demethylase activity. Proc Natl Acad Sci U S A 2022; 119:e2110348119. [PMID: 35858297 PMCID: PMC9303987 DOI: 10.1073/pnas.2110348119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 03/27/2022] [Indexed: 01/16/2023] Open
Abstract
The dichotomous behavior of superoxide dismutase-2 (SOD2) in cancer biology has long been acknowledged and more recently linked to different posttranslational forms of the enzyme. However, a distinctive activity underlying its tumor-promoting function is yet to be described. Here, we report that acetylation, one of such posttranslational modifications (PTMs), increases SOD2 affinity for iron, effectively changing the biochemical function of this enzyme from that of an antioxidant to a demethylase. Acetylated, iron-bound SOD2 localizes to the nucleus, promoting stem cell gene expression via removal of suppressive epigenetic marks such as H3K9me3 and H3K927me3. Particularly, H3K9me3 was specifically removed from regulatory regions upstream of Nanog and Oct-4, two pluripotency factors involved in cancer stem cell reprogramming. Phenotypically, cells expressing nucleus-targeted SOD2 (NLS-SOD2) have increased clonogenicity and metastatic potential. FeSOD2 operating as H3 demethylase requires H2O2 as substrate, which unlike cofactors of canonical demethylases (i.e., oxygen and 2-oxoglutarate), is more abundant in tumor cells than in normal tissue. Therefore, our results indicate that FeSOD2 is a demethylase with unique activities and functions in the promotion of cancer evolution toward metastatic phenotypes.
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Affiliation(s)
- Diego R. Coelho
- Department of Medicine, Division of Hematology Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Flavio R. Palma
- Department of Medicine, Division of Hematology Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Veronica Paviani
- Department of Medicine, Division of Hematology Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Chenxia He
- Department of Medicine, Division of Endocrinology, Metabolism and Molecular Medicine, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Jeanne M. Danes
- Department of Medicine, Division of Hematology Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Yunping Huang
- Department of Medicine, Division of Hematology Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Juliana C. P. Calado
- Department of Medicine, Division of Hematology Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Peter C. Hart
- College of Science, Health and Pharmacy, Roosevelt University, Schaumburg, IL 60173
| | - Cristina M. Furdui
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Leslie B. Poole
- Department of Biochemistry, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Matthew J. Schipma
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Quantitative Data Sciences Core and Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Marcelo G. Bonini
- Department of Medicine, Division of Hematology Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
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3
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Dijkwel Y, Tremethick DJ. The Role of the Histone Variant H2A.Z in Metazoan Development. J Dev Biol 2022; 10:jdb10030028. [PMID: 35893123 PMCID: PMC9326617 DOI: 10.3390/jdb10030028] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/12/2022] [Accepted: 06/23/2022] [Indexed: 12/10/2022] Open
Abstract
During the emergence and radiation of complex multicellular eukaryotes from unicellular ancestors, transcriptional systems evolved by becoming more complex to provide the basis for this morphological diversity. The way eukaryotic genomes are packaged into a highly complex structure, known as chromatin, underpins this evolution of transcriptional regulation. Chromatin structure is controlled by a variety of different epigenetic mechanisms, including the major mechanism for altering the biochemical makeup of the nucleosome by replacing core histones with their variant forms. The histone H2A variant H2A.Z is particularly important in early metazoan development because, without it, embryos cease to develop and die. However, H2A.Z is also required for many differentiation steps beyond the stage that H2A.Z-knockout embryos die. H2A.Z can facilitate the activation and repression of genes that are important for pluripotency and differentiation, and acts through a variety of different molecular mechanisms that depend upon its modification status, its interaction with histone and nonhistone partners, and where it is deposited within the genome. In this review, we discuss the current knowledge about the different mechanisms by which H2A.Z regulates chromatin function at various developmental stages and the chromatin remodeling complexes that determine when and where H2A.Z is deposited.
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Courtot L, Bournique E, Maric C, Guitton-Sert L, Madrid-Mencía M, Pancaldi V, Cadoret JC, Hoffmann JS, Bergoglio V. Low Replicative Stress Triggers Cell-Type Specific Inheritable Advanced Replication Timing. Int J Mol Sci 2021; 22:ijms22094959. [PMID: 34066960 PMCID: PMC8125030 DOI: 10.3390/ijms22094959] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/30/2021] [Accepted: 05/02/2021] [Indexed: 12/27/2022] Open
Abstract
DNA replication timing (RT), reflecting the temporal order of origin activation, is known as a robust and conserved cell-type specific process. Upon low replication stress, the slowing of replication forks induces well-documented RT delays associated to genetic instability, but it can also generate RT advances that are still uncharacterized. In order to characterize these advanced initiation events, we monitored the whole genome RT from six independent human cell lines treated with low doses of aphidicolin. We report that RT advances are cell-type-specific and involve large heterochromatin domains. Importantly, we found that some major late to early RT advances can be inherited by the unstressed next-cellular generation, which is a unique process that correlates with enhanced chromatin accessibility, as well as modified replication origin landscape and gene expression in daughter cells. Collectively, this work highlights how low replication stress may impact cellular identity by RT advances events at a subset of chromosomal domains.
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Affiliation(s)
- Lilas Courtot
- Centre de Recherches en Cancérologie de Toulouse (CRCT), UMR1037 Inserm, University Paul Sabatier III, ERL5294 CNRS, 2 Avenue Hubert Curien, 31037 Toulouse, France; (L.C.); (E.B.); (L.G.-S.); (M.M.-M.); (V.P.)
| | - Elodie Bournique
- Centre de Recherches en Cancérologie de Toulouse (CRCT), UMR1037 Inserm, University Paul Sabatier III, ERL5294 CNRS, 2 Avenue Hubert Curien, 31037 Toulouse, France; (L.C.); (E.B.); (L.G.-S.); (M.M.-M.); (V.P.)
| | - Chrystelle Maric
- Université de Paris, CNRS, Institut Jacques Monod, DNA Replication Pathologies Team, F-75006 Paris, France;
| | - Laure Guitton-Sert
- Centre de Recherches en Cancérologie de Toulouse (CRCT), UMR1037 Inserm, University Paul Sabatier III, ERL5294 CNRS, 2 Avenue Hubert Curien, 31037 Toulouse, France; (L.C.); (E.B.); (L.G.-S.); (M.M.-M.); (V.P.)
| | - Miguel Madrid-Mencía
- Centre de Recherches en Cancérologie de Toulouse (CRCT), UMR1037 Inserm, University Paul Sabatier III, ERL5294 CNRS, 2 Avenue Hubert Curien, 31037 Toulouse, France; (L.C.); (E.B.); (L.G.-S.); (M.M.-M.); (V.P.)
| | - Vera Pancaldi
- Centre de Recherches en Cancérologie de Toulouse (CRCT), UMR1037 Inserm, University Paul Sabatier III, ERL5294 CNRS, 2 Avenue Hubert Curien, 31037 Toulouse, France; (L.C.); (E.B.); (L.G.-S.); (M.M.-M.); (V.P.)
- Barcelona Supercomputing Center, 08034 Barcelona, Spain
| | - Jean-Charles Cadoret
- Université de Paris, CNRS, Institut Jacques Monod, DNA Replication Pathologies Team, F-75006 Paris, France;
- Correspondence: (J.-C.C.); (J.-S.H.); (V.B.)
| | - Jean-Sébastien Hoffmann
- Laboratoire de pathologie, Laboratoire d’excellence Toulouse Cancer, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irène-Joliot-Curie, CEDEX, 31059 Toulouse, France
- Correspondence: (J.-C.C.); (J.-S.H.); (V.B.)
| | - Valérie Bergoglio
- Centre de Recherches en Cancérologie de Toulouse (CRCT), UMR1037 Inserm, University Paul Sabatier III, ERL5294 CNRS, 2 Avenue Hubert Curien, 31037 Toulouse, France; (L.C.); (E.B.); (L.G.-S.); (M.M.-M.); (V.P.)
- Correspondence: (J.-C.C.); (J.-S.H.); (V.B.)
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5
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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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6
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Wu X, Kabalane H, Kahli M, Petryk N, Laperrousaz B, Jaszczyszyn Y, Drillon G, Nicolini FE, Perot G, Robert A, Fund C, Chibon F, Xia R, Wiels J, Argoul F, Maguer-Satta V, Arneodo A, Audit B, Hyrien O. Developmental and cancer-associated plasticity of DNA replication preferentially targets GC-poor, lowly expressed and late-replicating regions. Nucleic Acids Res 2019; 46:10157-10172. [PMID: 30189101 PMCID: PMC6212843 DOI: 10.1093/nar/gky797] [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: 08/06/2018] [Accepted: 08/24/2018] [Indexed: 01/08/2023] Open
Abstract
The spatiotemporal program of metazoan DNA replication is regulated during development and altered in cancers. We have generated novel OK-seq, Repli-seq and RNA-seq data to compare the DNA replication and gene expression programs of twelve cancer and non-cancer human cell types. Changes in replication fork directionality (RFD) determined by OK-seq are widespread but more frequent within GC-poor isochores and largely disconnected from transcription changes. Cancer cell RFD profiles cluster with non-cancer cells of similar developmental origin but not with different cancer types. Importantly, recurrent RFD changes are detected in specific tumour progression pathways. Using a model for establishment and early progression of chronic myeloid leukemia (CML), we identify 1027 replication initiation zones (IZs) that progressively change efficiency during long-term expression of the BCR-ABL1 oncogene, being twice more often downregulated than upregulated. Prolonged expression of BCR-ABL1 results in targeting of new IZs and accentuation of previous efficiency changes. Targeted IZs are predominantly located in GC-poor, late replicating gene deserts and frequently silenced in late CML. Prolonged expression of BCR-ABL1 results in massive deletion of GC-poor, late replicating DNA sequences enriched in origin silencing events. We conclude that BCR-ABL1 expression progressively affects replication and stability of GC-poor, late-replicating regions during CML progression.
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Affiliation(s)
- Xia Wu
- Institut de Biologie de l'École Normale Supérieure (IBENS), Département de Biologie, Ecole Normale Supérieure, CNRS, Inserm, PSL Research University, F-75005 Paris, France.,Physics Department, East China Normal University, Shanghai, China
| | - Hadi Kabalane
- Univ Lyon, ENS de Lyon, Univ Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342 Lyon, France
| | - Malik Kahli
- Institut de Biologie de l'École Normale Supérieure (IBENS), Département de Biologie, Ecole Normale Supérieure, CNRS, Inserm, PSL Research University, F-75005 Paris, France
| | - Nataliya Petryk
- Institut de Biologie de l'École Normale Supérieure (IBENS), Département de Biologie, Ecole Normale Supérieure, CNRS, Inserm, PSL Research University, F-75005 Paris, France
| | - Bastien Laperrousaz
- Univ Lyon, ENS de Lyon, Univ Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342 Lyon, France.,CNRS UMR5286, INSERM U1052, Centre de Recherche en Cancérologie de Lyon, F- 69008 Lyon, France
| | - Yan Jaszczyszyn
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Guenola Drillon
- Univ Lyon, ENS de Lyon, Univ Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342 Lyon, France
| | - Frank-Emmanuel Nicolini
- CNRS UMR5286, INSERM U1052, Centre de Recherche en Cancérologie de Lyon, F- 69008 Lyon, France.,Centre Léon Bérard, F-69008 Lyon, France
| | - Gaëlle Perot
- INSERM U1218, Institut Bergonié, F-33000 Bordeaux, France
| | - Aude Robert
- UMR 8126, Université Paris-Sud Paris-Saclay, CNRS, Institut Gustave Roussy, Villejuif, France
| | - Cédric Fund
- École Normale Supérieure, PSL Research University, CNRS, Inserm, IBENS, Plateforme Génomique, 75005 Paris, France
| | | | - Ruohong Xia
- Physics Department, East China Normal University, Shanghai, China
| | - Joëlle Wiels
- UMR 8126, Université Paris-Sud Paris-Saclay, CNRS, Institut Gustave Roussy, Villejuif, France
| | - Françoise Argoul
- LOMA, Université de Bordeaux, CNRS, UMR 5798, F-33405 Talence, France
| | - Véronique Maguer-Satta
- CNRS UMR5286, INSERM U1052, Centre de Recherche en Cancérologie de Lyon, F- 69008 Lyon, France
| | - Alain Arneodo
- LOMA, Université de Bordeaux, CNRS, UMR 5798, F-33405 Talence, France
| | - Benjamin Audit
- Univ Lyon, ENS de Lyon, Univ Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342 Lyon, France
| | - Olivier Hyrien
- Institut de Biologie de l'École Normale Supérieure (IBENS), Département de Biologie, Ecole Normale Supérieure, CNRS, Inserm, PSL Research University, F-75005 Paris, France
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7
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Brunet FG, Audit B, Drillon G, Argoul F, Volff JN, Arneodo A. Evidence for DNA Sequence Encoding of an Accessible Nucleosomal Array across Vertebrates. Biophys J 2018; 114:2308-2316. [PMID: 29580552 PMCID: PMC6028776 DOI: 10.1016/j.bpj.2018.02.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/07/2018] [Accepted: 02/20/2018] [Indexed: 12/15/2022] Open
Abstract
Nucleosome-depleted regions around which nucleosomes order following the "statistical" positioning scenario were recently shown to be encoded in the DNA sequence in human. This intrinsic nucleosomal ordering strongly correlates with oscillations in the local GC content as well as with the interspecies and intraspecies mutation profiles, revealing the existence of both positive and negative selection. In this letter, we show that these predicted nucleosome inhibitory energy barriers (NIEBs) with compacted neighboring nucleosomes are indeed ubiquitous to all vertebrates tested. These 1 kb-sized chromatin patterns are widely distributed along vertebrate chromosomes, overall covering more than a third of the genome. We have previously observed in human deviations from neutral evolution at these genome-wide distributed regions, which we interpreted as a possible indication of the selection of an open, accessible, and dynamic nucleosomal array to constitutively facilitate the epigenetic regulation of nuclear functions in a cell-type-specific manner. As a first, very appealing observation supporting this hypothesis, we report evidence of a strong association between NIEB borders and the poly(A) tails of Alu sequences in human. These results suggest that NIEBs provide adequate chromatin patterns favorable to the integration of Alu retrotransposons and, more generally to various transposable elements in the genomes of primates and other vertebrates.
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Affiliation(s)
- Frédéric G Brunet
- Institut de Génomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Univ Claude Bernard Lyon 1, Lyon, France
| | - Benjamin Audit
- Univ Lyon, ENS de Lyon, Univ Claude Bernard Lyon 1, CNRS Laboratoire de Physique, Lyon, France
| | - Guénola Drillon
- Univ Lyon, ENS de Lyon, Univ Claude Bernard Lyon 1, CNRS Laboratoire de Physique, Lyon, France
| | - Françoise Argoul
- Univ Lyon, ENS de Lyon, Univ Claude Bernard Lyon 1, CNRS Laboratoire de Physique, Lyon, France; LOMA, Université de Bordeaux, CNRS UMR 5798, Talence, France
| | - Jean-Nicolas Volff
- Institut de Génomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Univ Claude Bernard Lyon 1, Lyon, France
| | - Alain Arneodo
- Univ Lyon, ENS de Lyon, Univ Claude Bernard Lyon 1, CNRS Laboratoire de Physique, Lyon, France; LOMA, Université de Bordeaux, CNRS UMR 5798, Talence, France.
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8
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Abstract
Pluripotent cells are characterized by a globally open and accessible chromatin organization that is thought to contribute to cellular plasticity and developmental decision-making. We recently identified the pluripotency factor Nanog as a key regulator of this form of chromatin architecture in mouse embryonic stem cells. In particular, we demonstrated that the transcription factors Nanog and Sall1 co-dependently mediate the epigenetic state of pericentromeric heterochromatin to reinforce a more open and accessible organization in pluripotent cells. Here, we summarize our main findings and place the work into a broader context. We explore how heterochromatin domains could be targets of transcriptional networks in pluripotent cells and are coordinated with cell state. We propose this integration may be to balance the requirement for a dynamic and plastic chromatin organization in pluripotent cells, together with priming for a more restrictive nuclear compartmentalization that is triggered rapidly upon lineage commitment.
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9
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Boulos RE, Tremblay N, Arneodo A, Borgnat P, Audit B. Multi-scale structural community organisation of the human genome. BMC Bioinformatics 2017; 18:209. [PMID: 28399820 PMCID: PMC5387268 DOI: 10.1186/s12859-017-1616-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 03/28/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Structural interaction frequency matrices between all genome loci are now experimentally achievable thanks to high-throughput chromosome conformation capture technologies. This ensues a new methodological challenge for computational biology which consists in objectively extracting from these data the structural motifs characteristic of genome organisation. RESULTS We deployed the fast multi-scale community mining algorithm based on spectral graph wavelets to characterise the networks of intra-chromosomal interactions in human cell lines. We observed that there exist structural domains of all sizes up to chromosome length and demonstrated that the set of structural communities forms a hierarchy of chromosome segments. Hence, at all scales, chromosome folding predominantly involves interactions between neighbouring sites rather than the formation of links between distant loci. CONCLUSIONS Multi-scale structural decomposition of human chromosomes provides an original framework to question structural organisation and its relationship to functional regulation across the scales. By construction the proposed methodology is independent of the precise assembly of the reference genome and is thus directly applicable to genomes whose assembly is not fully determined.
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Affiliation(s)
- Rasha E Boulos
- Univ Lyon, Ens de Lyon, Univ Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342, Lyon, France.,Present address: Montpellier Cancer Institute (ICM), Montpellier Cancer Research Institute (IRCM) Inserm U1194, University of Montpellier, Montpellier, France
| | - Nicolas Tremblay
- Univ Lyon, Ens de Lyon, Univ Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342, Lyon, France.,Present address: CNRS, GIPSA-lab, Grenoble, France
| | - Alain Arneodo
- Univ Lyon, Ens de Lyon, Univ Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342, Lyon, France.,Present address: LOMA, Université de Bordeaux, CNRS, UMR 5798, 51 Cours de le Libération, Talence, 33405, France
| | - Pierre Borgnat
- Univ Lyon, Ens de Lyon, Univ Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342, Lyon, France
| | - Benjamin Audit
- Univ Lyon, Ens de Lyon, Univ Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, F-69342, Lyon, France.
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10
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Festuccia N, Gonzalez I, Navarro P. The Epigenetic Paradox of Pluripotent ES Cells. J Mol Biol 2016; 429:1476-1503. [PMID: 27988225 DOI: 10.1016/j.jmb.2016.12.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/02/2016] [Accepted: 12/05/2016] [Indexed: 12/15/2022]
Abstract
The propagation and maintenance of gene expression programs are at the foundation of the preservation of cell identity. A large and complex set of epigenetic mechanisms enables the long-term stability and inheritance of transcription states. A key property of authentic epigenetic regulation is being independent from the instructive signals used for its establishment. This makes epigenetic regulation, particularly epigenetic silencing, extremely robust and powerful to lock regulatory states and stabilise cell identity. In line with this, the establishment of epigenetic silencing during development restricts cell potency and maintains the cell fate choices made by transcription factors (TFs). However, how more immature cells that have not yet established their definitive fate maintain their transitory identity without compromising their responsiveness to signalling cues remains unclear. A paradigmatic example is provided by pluripotent embryonic stem (ES) cells derived from a transient population of cells of the blastocyst. Here, we argue that ES cells represent an interesting "epigenetic paradox": even though they are captured in a self-renewing state characterised by extremely efficient maintenance of their identity, which is a typical manifestation of robust epigenetic regulation, they seem not to heavily rely on classical epigenetic mechanisms. Indeed, self-renewal strictly depends on the TFs that previously instructed their undifferentiated identity and relies on a particular signalling-dependent chromatin state where repressive chromatin marks play minor roles. Although this "epigenetic paradox" may underlie their exquisite responsiveness to developmental cues, it suggests that alternative mechanisms to faithfully propagate gene regulatory states might be prevalent in ES cells.
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Affiliation(s)
- Nicola Festuccia
- Epigenetics of Stem Cells, Department of Stem Cell and Developmental Biology, Institut Pasteur, CNRS UMR3738, 25 rue du Docteur Roux, 75015 Paris, France
| | - Inma Gonzalez
- Epigenetics of Stem Cells, Department of Stem Cell and Developmental Biology, Institut Pasteur, CNRS UMR3738, 25 rue du Docteur Roux, 75015 Paris, France
| | - Pablo Navarro
- Epigenetics of Stem Cells, Department of Stem Cell and Developmental Biology, Institut Pasteur, CNRS UMR3738, 25 rue du Docteur Roux, 75015 Paris, France.
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Drillon G, Audit B, Argoul F, Arneodo A. Evidence of selection for an accessible nucleosomal array in human. BMC Genomics 2016; 17:526. [PMID: 27472913 PMCID: PMC4966569 DOI: 10.1186/s12864-016-2880-2] [Citation(s) in RCA: 21] [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: 12/14/2015] [Accepted: 07/04/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Recently, a physical model of nucleosome formation based on sequence-dependent bending properties of the DNA double-helix has been used to reveal some enrichment of nucleosome-inhibiting energy barriers (NIEBs) nearby ubiquitous human "master" replication origins. Here we use this model to predict the existence of about 1.6 millions NIEBs over the 22 human autosomes. RESULTS We show that these high energy barriers of mean size 153 bp correspond to nucleosome-depleted regions (NDRs) in vitro, as expected, but also in vivo. On either side of these NIEBs, we observe, in vivo and in vitro, a similar compacted nucleosome ordering, suggesting an absence of chromatin remodeling. This nucleosomal ordering strongly correlates with oscillations of the GC content as well as with the interspecies and intraspecies mutation profiles along these regions. Comparison of these divergence rates reveals the existence of both positive and negative selections linked to nucleosome positioning around these intrinsic NDRs. Overall, these NIEBs and neighboring nucleosomes cover 37.5 % of the human genome where nucleosome occupancy is stably encoded in the DNA sequence. These 1 kb-sized regions of intrinsic nucleosome positioning are equally found in GC-rich and GC-poor isochores, in early and late replicating regions, in intergenic and genic regions but not at gene promoters. CONCLUSION The source of selection pressure on the NIEBs has yet to be resolved in future work. One possible scenario is that these widely distributed chromatin patterns have been selected in human to impair the condensation of the nucleosomal array into the 30 nm chromatin fiber, so as to facilitate the epigenetic regulation of nuclear functions in a cell-type-specific manner.
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Affiliation(s)
- Guénola Drillon
- Univ Lyon, Ens de Lyon, Univ Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, Lyon, F-69342 France
| | - Benjamin Audit
- Univ Lyon, Ens de Lyon, Univ Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, Lyon, F-69342 France
| | - Françoise Argoul
- Univ Lyon, Ens de Lyon, Univ Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, Lyon, F-69342 France
- LOMA, Université de Bordeaux, CNRS, UMR 5798, 51 Cours de le Libération, Talence, F-33405 France
| | - Alain Arneodo
- Univ Lyon, Ens de Lyon, Univ Claude Bernard Lyon 1, CNRS, Laboratoire de Physique, Lyon, F-69342 France
- LOMA, Université de Bordeaux, CNRS, UMR 5798, 51 Cours de le Libération, Talence, F-33405 France
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Deciphering DNA replication dynamics in eukaryotic cell populations in relation with their averaged chromatin conformations. Sci Rep 2016; 6:22469. [PMID: 26935043 PMCID: PMC4776152 DOI: 10.1038/srep22469] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 02/16/2016] [Indexed: 12/16/2022] Open
Abstract
We propose a non-local model of DNA replication that takes into account the observed
uncertainty on the position and time of replication initiation in eukaryote cell
populations. By picturing replication initiation as a two-state system and
considering all possible transition configurations, and by taking into account the
chromatin’s fractal dimension, we derive an analytical expression for
the rate of replication initiation. This model predicts with no free parameter the
temporal profiles of initiation rate, replication fork density and fraction of
replicated DNA, in quantitative agreement with corresponding experimental data from
both S. cerevisiae and human cells and provides a quantitative estimate of
initiation site redundancy. This study shows that, to a large extent, the program
that regulates the dynamics of eukaryotic DNA replication is a collective phenomenon
that emerges from the stochastic nature of replication origins initiation.
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Harvey AJ, Rathjen J, Gardner DK. Metaboloepigenetic Regulation of Pluripotent Stem Cells. Stem Cells Int 2015; 2016:1816525. [PMID: 26839556 PMCID: PMC4709785 DOI: 10.1155/2016/1816525] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 09/29/2015] [Indexed: 12/19/2022] Open
Abstract
The differentiation of pluripotent stem cells is associated with extensive changes in metabolism, as well as widespread remodeling of the epigenetic landscape. Epigenetic regulation is essential for the modulation of differentiation, being responsible for cell type specific gene expression patterns through the modification of DNA and histones, thereby establishing cell identity. Each cell type has its own idiosyncratic pattern regarding the use of specific metabolic pathways. Rather than simply being perceived as a means of generating ATP and building blocks for cell growth and division, cellular metabolism can directly influence cellular regulation and the epigenome. Consequently, the significance of nutrients and metabolites as regulators of differentiation is central to understanding how cells interact with their immediate environment. This review serves to integrate studies on pluripotent stem cell metabolism, and the regulation of DNA methylation and acetylation and identifies areas in which current knowledge is limited.
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Affiliation(s)
- Alexandra J. Harvey
- Stem Cells Australia, Parkville, VIC 3010, Australia
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Joy Rathjen
- Stem Cells Australia, Parkville, VIC 3010, Australia
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
- School of Medicine, University of Tasmania, Hobart, TAS 7000, Australia
| | - David K. Gardner
- Stem Cells Australia, Parkville, VIC 3010, Australia
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
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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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