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Attar AG, Paturej J, Banigan EJ, Erbaş A. Chromatin phase separation and nuclear shape fluctuations are correlated in a polymer model of the nucleus. Nucleus 2024; 15:2351957. [PMID: 38753956 DOI: 10.1080/19491034.2024.2351957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/28/2024] [Indexed: 05/18/2024] Open
Abstract
Abnormal cell nuclear shapes are hallmarks of diseases, including progeria, muscular dystrophy, and many cancers. Experiments have shown that disruption of heterochromatin and increases in euchromatin lead to nuclear deformations, such as blebs and ruptures. However, the physical mechanisms through which chromatin governs nuclear shape are poorly understood. To investigate how heterochromatin and euchromatin might govern nuclear morphology, we studied chromatin microphase separation in a composite coarse-grained polymer and elastic shell simulation model. By varying chromatin density, heterochromatin composition, and heterochromatin-lamina interactions, we show how the chromatin phase organization may perturb nuclear shape. Increasing chromatin density stabilizes the lamina against large fluctuations. However, increasing heterochromatin levels or heterochromatin-lamina interactions enhances nuclear shape fluctuations by a "wetting"-like interaction. In contrast, fluctuations are insensitive to heterochromatin's internal structure. Our simulations suggest that peripheral heterochromatin accumulation could perturb nuclear morphology, while nuclear shape stabilization likely occurs through mechanisms other than chromatin microphase organization.
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Affiliation(s)
- Ali Goktug Attar
- UNAM-National Nanotechnology Research Center and Institute of Materials Science & Nanotechnology, Bilkent University, Ankara, Turkey
| | | | - Edward J Banigan
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Aykut Erbaş
- UNAM-National Nanotechnology Research Center and Institute of Materials Science & Nanotechnology, Bilkent University, Ankara, Turkey
- Institute of Physics, University of Silesia, Chorzów, Poland
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2
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Martitz A, Schulz EG. Spatial orchestration of the genome: topological reorganisation during X-chromosome inactivation. Curr Opin Genet Dev 2024; 86:102198. [PMID: 38663040 DOI: 10.1016/j.gde.2024.102198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 03/21/2024] [Accepted: 04/05/2024] [Indexed: 06/11/2024]
Abstract
Genomes are organised through hierarchical structures, ranging from local kilobase-scale cis-regulatory contacts to large chromosome territories. Most notably, (sub)-compartments partition chromosomes according to transcriptional activity, while topologically associating domains (TADs) define cis-regulatory landscapes. The inactive X chromosome in mammals has provided unique insights into the regulation and function of the three-dimensional (3D) genome. Concurrent with silencing of the majority of genes and major alterations of its chromatin state, the X chromosome undergoes profound spatial rearrangements at multiple scales. These include the emergence of megadomains, alterations of the compartment structure and loss of the majority of TADs. Moreover, the Xist locus, which orchestrates X-chromosome inactivation, has provided key insights into regulation and function of regulatory domains. This review provides an overview of recent insights into the control of these structural rearrangements and contextualises them within a broader understanding of 3D genome organisation.
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Affiliation(s)
- Alexandra Martitz
- Systems Epigenetics, Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany; Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Edda G Schulz
- Systems Epigenetics, Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany.
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3
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Afanasyev AY, Kim Y, Tolokh IS, Sharakhov IV, Onufriev AV. The probability of chromatin to be at the nuclear lamina has no systematic effect on its transcription level in fruit flies. Epigenetics Chromatin 2024; 17:13. [PMID: 38705995 PMCID: PMC11071202 DOI: 10.1186/s13072-024-00528-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/08/2024] [Indexed: 05/07/2024] Open
Abstract
BACKGROUND Multiple studies have demonstrated a negative correlation between gene expression and positioning of genes at the nuclear envelope (NE) lined by nuclear lamina, but the exact relationship remains unclear, especially in light of the highly stochastic, transient nature of the gene association with the NE. RESULTS In this paper, we ask whether there is a causal, systematic, genome-wide relationship between the expression levels of the groups of genes in topologically associating domains (TADs) of Drosophila nuclei and the probabilities of TADs to be found at the NE. To investigate the nature of this possible relationship, we combine a coarse-grained dynamic model of the entire Drosophila nucleus with genome-wide gene expression data; we analyze the TAD averaged transcription levels of genes against the probabilities of individual TADs to be in contact with the NE in the control and lamins-depleted nuclei. Our findings demonstrate that, within the statistical error margin, the stochastic positioning of Drosophila melanogaster TADs at the NE does not, by itself, systematically affect the mean level of gene expression in these TADs, while the expected negative correlation is confirmed. The correlation is weak and disappears completely for TADs not containing lamina-associated domains (LADs) or TADs containing LADs, considered separately. Verifiable hypotheses regarding the underlying mechanism for the presence of the correlation without causality are discussed. These include the possibility that the epigenetic marks and affinity to the NE of a TAD are determined by various non-mutually exclusive mechanisms and remain relatively stable during interphase. CONCLUSIONS At the level of TADs, the probability of chromatin being in contact with the nuclear envelope has no systematic, causal effect on the transcription level in Drosophila. The conclusion is reached by combining model-derived time-evolution of TAD locations within the nucleus with their experimental gene expression levels.
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Affiliation(s)
- Alexander Y Afanasyev
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Yoonjin Kim
- Department of Computer Science, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Igor S Tolokh
- Department of Computer Science, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Igor V Sharakhov
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
| | - Alexey V Onufriev
- Department of Computer Science, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
- Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
- Center for Soft Matter and Biological Physics, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
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Keller D, Stinus S, Umlauf D, Gourbeyre E, Biot E, Olivier N, Mahou P, Beaurepaire E, Andrey P, Crabbe L. Non-random spatial organization of telomeres varies during the cell cycle and requires LAP2 and BAF. iScience 2024; 27:109343. [PMID: 38510147 PMCID: PMC10951912 DOI: 10.1016/j.isci.2024.109343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 11/30/2023] [Accepted: 02/22/2024] [Indexed: 03/22/2024] Open
Abstract
Spatial genome organization within the nucleus influences major biological processes and is impacted by the configuration of linear chromosomes. Here, we applied 3D spatial statistics and modeling on high-resolution telomere and centromere 3D-structured illumination microscopy images in cancer cells. We found a multi-scale organization of telomeres that dynamically evolved from a mixed clustered-and-regular distribution in early G1 to a purely regular distribution as cells progressed through the cell cycle. In parallel, our analysis revealed two pools of peripheral and internal telomeres, the proportions of which were inverted during the cell cycle. We then conducted a targeted screen using MadID to identify the molecular pathways driving or maintaining telomere anchoring to the nuclear envelope observed in early G1. Lamina-associated polypeptide (LAP) proteins were found transiently localized to telomeres in anaphase, a stage where LAP2α initiates the reformation of the nuclear envelope, and impacted telomere redistribution in the next interphase together with their partner barrier-to-autointegration factor (BAF).
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Affiliation(s)
- Debora Keller
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France
- Laboratory for Optics and Biosciences, École polytechnique, CNRS, INSERM, IP Paris, 91128 Palaiseau, France
| | - Sonia Stinus
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - David Umlauf
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Edith Gourbeyre
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Eric Biot
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Nicolas Olivier
- Laboratory for Optics and Biosciences, École polytechnique, CNRS, INSERM, IP Paris, 91128 Palaiseau, France
| | - Pierre Mahou
- Laboratory for Optics and Biosciences, École polytechnique, CNRS, INSERM, IP Paris, 91128 Palaiseau, France
| | - Emmanuel Beaurepaire
- Laboratory for Optics and Biosciences, École polytechnique, CNRS, INSERM, IP Paris, 91128 Palaiseau, France
| | - Philippe Andrey
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Laure Crabbe
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France
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5
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Pudelko L, Cabianca DS. The influencers' era: how the environment shapes chromatin in 3D. Curr Opin Genet Dev 2024; 85:102173. [PMID: 38417271 DOI: 10.1016/j.gde.2024.102173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 01/26/2024] [Accepted: 02/06/2024] [Indexed: 03/01/2024]
Abstract
Environment-epigenome interactions are emerging as contributors to disease risk and health outcomes. In fact, organisms outside of the laboratory are constantly exposed to environmental changes that can influence chromatin regulation at multiple levels, potentially impacting on genome function. In this review, we will summarize recent findings on how major external cues impact on 3D chromatin organization in different experimental systems. We will describe environment-induced 3D genome alterations ranging from chromatin accessibility to the spatial distribution of the genome and discuss their role in regulating gene expression.
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Affiliation(s)
- Lorenz Pudelko
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany; Faculty of Medicine, Ludwig-Maximilians Universität München, Munich, Germany. https://twitter.com/@lorenz_pudelko
| | - Daphne S Cabianca
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany.
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6
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Salinas-Pena M, Rebollo E, Jordan A. Imaging analysis of six human histone H1 variants reveals universal enrichment of H1.2, H1.3, and H1.5 at the nuclear periphery and nucleolar H1X presence. eLife 2024; 12:RP91306. [PMID: 38530350 DOI: 10.7554/elife.91306] [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: 03/27/2024] Open
Abstract
Histone H1 participates in chromatin condensation and regulates nuclear processes. Human somatic cells may contain up to seven histone H1 variants, although their functional heterogeneity is not fully understood. Here, we have profiled the differential nuclear distribution of the somatic H1 repertoire in human cells through imaging techniques including super-resolution microscopy. H1 variants exhibit characteristic distribution patterns in both interphase and mitosis. H1.2, H1.3, and H1.5 are universally enriched at the nuclear periphery in all cell lines analyzed and co-localize with compacted DNA. H1.0 shows a less pronounced peripheral localization, with apparent variability among different cell lines. On the other hand, H1.4 and H1X are distributed throughout the nucleus, being H1X universally enriched in high-GC regions and abundant in the nucleoli. Interestingly, H1.4 and H1.0 show a more peripheral distribution in cell lines lacking H1.3 and H1.5. The differential distribution patterns of H1 suggest specific functionalities in organizing lamina-associated domains or nucleolar activity, which is further supported by a distinct response of H1X or phosphorylated H1.4 to the inhibition of ribosomal DNA transcription. Moreover, H1 variants depletion affects chromatin structure in a variant-specific manner. Concretely, H1.2 knock-down, either alone or combined, triggers a global chromatin decompaction. Overall, imaging has allowed us to distinguish H1 variants distribution beyond the segregation in two groups denoted by previous ChIP-Seq determinations. Our results support H1 variants heterogeneity and suggest that variant-specific functionality can be shared between different cell types.
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Affiliation(s)
| | - Elena Rebollo
- Molecular Biology Institute of Barcelona (IBMB-CSIC), Barcelona, Spain
| | - Albert Jordan
- Molecular Biology Institute of Barcelona (IBMB-CSIC), Barcelona, Spain
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7
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Hall LL, Creamer KM, Byron M, Lawrence JB. Differences in Alu vs L1-rich chromosome bands underpin architectural reorganization of the inactive-X chromosome and SAHFs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.09.574742. [PMID: 38260534 PMCID: PMC10802495 DOI: 10.1101/2024.01.09.574742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The linear DNA sequence of mammalian chromosomes is organized in large blocks of DNA with similar sequence properties, producing a pattern of dark and light staining bands on mitotic chromosomes. Cytogenetic banding is essentially invariant between people and cell-types and thus may be assumed unrelated to genome regulation. We investigate whether large blocks of Alu-rich R-bands and L1-rich G-bands provide a framework upon which functional genome architecture is built. We examine two models of large-scale chromatin condensation: X-chromosome inactivation and formation of senescence-associated heterochromatin foci (SAHFs). XIST RNA triggers gene silencing but also formation of the condensed Barr Body (BB), thought to reflect cumulative gene silencing. However, we find Alu-rich regions are depleted from the L1-rich BB, supporting it is a dense core but not the entire chromosome. Alu-rich bands are also gene-rich, affirming our earlier findings that genes localize at the outer periphery of the BB. SAHFs similarly form within each territory by coalescence of syntenic L1 regions depleted for highly Alu-rich DNA. Analysis of senescent cell Hi-C data also shows large contiguous blocks of G-band and R-band DNA remodel as a segmental unit. Entire dark-bands gain distal intrachromosomal interactions as L1-rich regions form the SAHF. Most striking is that sharp Alu peaks within R-bands resist these changes in condensation. We further show that Chr19, which is exceptionally Alu rich, fails to form a SAHF. Collective results show regulation of genome architecture corresponding to large blocks of DNA and demonstrate resistance of segments with high Alu to chromosome condensation.
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Affiliation(s)
- Lisa L. Hall
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Kevin M. Creamer
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Meg Byron
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Jeanne B. Lawrence
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
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8
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Lee CSK, Weiβ M, Hamperl S. Where and when to start: Regulating DNA replication origin activity in eukaryotic genomes. Nucleus 2023; 14:2229642. [PMID: 37469113 PMCID: PMC10361152 DOI: 10.1080/19491034.2023.2229642] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/20/2023] [Accepted: 06/21/2023] [Indexed: 07/21/2023] Open
Abstract
In eukaryotic genomes, hundreds to thousands of potential start sites of DNA replication named origins are dispersed across each of the linear chromosomes. During S-phase, only a subset of origins is selected in a stochastic manner to assemble bidirectional replication forks and initiate DNA synthesis. Despite substantial progress in our understanding of this complex process, a comprehensive 'identity code' that defines origins based on specific nucleotide sequences, DNA structural features, the local chromatin environment, or 3D genome architecture is still missing. In this article, we review the genetic and epigenetic features of replication origins in yeast and metazoan chromosomes and highlight recent insights into how this flexibility in origin usage contributes to nuclear organization, cell growth, differentiation, and genome stability.
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Affiliation(s)
- Clare S K Lee
- Chromosome Dynamics and Genome Stability, Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Matthias Weiβ
- Chromosome Dynamics and Genome Stability, Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
| | - Stephan Hamperl
- Chromosome Dynamics and Genome Stability, Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
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9
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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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10
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Balasooriya GI, Wee TL, Spector DL. A sub-set of guanine- and cytosine-rich genes are actively transcribed at the nuclear Lamin B1 region. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.28.564411. [PMID: 37961255 PMCID: PMC10634887 DOI: 10.1101/2023.10.28.564411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Chromatin organization in the mammalian cell nucleus plays a vital role in the regulation of gene expression. The lamina-associated domain at the inner nuclear membrane has been proposed to harbor heterochromatin, while the nuclear interior has been shown to contain most of the euchromatin. Here, we show that a sub-set of actively transcribing genes, marked by RNA Pol II pSer2, are associated with Lamin B1 at the inner nuclear envelop in mESCs and the number of genes proportionally increases upon in vitro differentiation of mESC to olfactory precursor cells. These nuclear periphery-associated actively transcribing genes primarily represent housekeeping genes, and their gene bodies are significantly enriched with guanine and cytosine compared to genes actively transcribed at the nuclear interior. We found the promoters of these genes to also be significantly enriched with guanine and to be predominantly regulated by zinc finger protein transcription factors. We provide evidence supporting the emerging notion that the Lamin B1 region is not solely transcriptionally silent.
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11
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Al-Refaie N, Padovani F, Binando F, Hornung J, Zhao Q, Towbin BD, Cenik ES, Stroustrup N, Schmoller KM, Cabianca DS. An mTOR/RNA pol I axis shapes chromatin architecture in response to fasting. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.22.550032. [PMID: 37503059 PMCID: PMC10370172 DOI: 10.1101/2023.07.22.550032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Chromatin architecture is a fundamental mediator of genome function. Fasting is a major environmental cue across the animal kingdom. Yet, how it impacts on 3D genome organization is unknown. Here, we show that fasting induces a reversible and large-scale spatial reorganization of chromatin in C. elegans . This fasting-induced 3D genome reorganization requires inhibition of the nutrient-sensing mTOR pathway, a major regulator of ribosome biogenesis. Remarkably, loss of transcription by RNA Pol I, but not RNA Pol II nor Pol III, induces a similar 3D genome reorganization in fed animals, and prevents the restoration of the fed-state architecture upon restoring nutrients to fasted animals. Our work documents the first large-scale chromatin reorganization triggered by fasting and reveals that mTOR and RNA Pol I shape genome architecture in response to nutrients.
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12
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Tolokh IS, Kinney NA, Sharakhov IV, Onufriev AV. Strong interactions between highly dynamic lamina-associated domains and the nuclear envelope stabilize the 3D architecture of Drosophila interphase chromatin. Epigenetics Chromatin 2023; 16:21. [PMID: 37254161 PMCID: PMC10228000 DOI: 10.1186/s13072-023-00492-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 05/04/2023] [Indexed: 06/01/2023] Open
Abstract
BACKGROUND Interactions among topologically associating domains (TADs), and between the nuclear envelope (NE) and lamina-associated domains (LADs) are expected to shape various aspects of three-dimensional (3D) chromatin structure and dynamics; however, relevant genome-wide experiments that may provide statistically significant conclusions remain difficult. RESULTS We have developed a coarse-grained dynamical model of D. melanogaster nuclei at TAD resolution that explicitly accounts for four distinct epigenetic classes of TADs and LAD-NE interactions. The model is parameterized to reproduce the experimental Hi-C map of the wild type (WT) nuclei; it describes time evolution of the chromatin over the G1 phase of the interphase. The simulations include an ensemble of nuclei, corresponding to the experimentally observed set of several possible mutual arrangements of chromosomal arms. The model is validated against multiple structural features of chromatin from several different experiments not used in model development. Predicted positioning of all LADs at the NE is highly dynamic-the same LAD can attach, detach and move far away from the NE multiple times during interphase. The probabilities of LADs to be in contact with the NE vary by an order of magnitude, despite all having the same affinity to the NE in the model. These probabilities are mostly determined by a highly variable local linear density of LADs along the genome, which also has the same strong effect on the predicted positioning of individual TADs -- higher probability of a TAD to be near NE is largely determined by a higher linear density of LADs surrounding this TAD. The distribution of LADs along the chromosome chains plays a notable role in maintaining a non-random average global structure of chromatin. Relatively high affinity of LADs to the NE in the WT nuclei substantially reduces sensitivity of the global radial chromatin distribution to variations in the strength of TAD-TAD interactions compared to the lamin depleted nuclei, where a small (0.5 kT) increase of cross-type TAD-TAD interactions doubles the chromatin density in the central nucleus region. CONCLUSIONS A dynamical model of the entire fruit fly genome makes multiple genome-wide predictions of biological interest. The distribution of LADs along the chromatin chains affects their probabilities to be in contact with the NE and radial positioning of highly mobile TADs, playing a notable role in creating a non-random average global structure of the chromatin. We conjecture that an important role of attractive LAD-NE interactions is to stabilize global chromatin structure against inevitable cell-to-cell variations in TAD-TAD interactions.
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Affiliation(s)
- Igor S. Tolokh
- Department of Computer Science, Virginia Tech, Blacksburg, VA 24061 USA
| | - Nicholas Allen Kinney
- Department of Computer Science, Virginia Tech, Blacksburg, VA 24061 USA
- Department of Entomology, Virginia Tech, Blacksburg, VA 24061 USA
- Edward Via College of Osteopathic Medicine, 2265 Kraft Drive, Blacksburg, VA 24060 USA
| | | | - Alexey V. Onufriev
- Department of Computer Science, Virginia Tech, Blacksburg, VA 24061 USA
- Department of Physics, Virginia Tech, Blacksburg, VA 24061 USA
- Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA 24061 USA
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13
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Li S, Shen X. Long interspersed nuclear element 1 and B1/Alu repeats blueprint genome compartmentalization. Curr Opin Genet Dev 2023; 80:102049. [PMID: 37229928 DOI: 10.1016/j.gde.2023.102049] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 04/14/2023] [Accepted: 04/15/2023] [Indexed: 05/27/2023]
Abstract
The organization of the genome into euchromatin and heterochromatin has been known for almost 100 years [1]. More than 50% of mammalian genomes contain repetitive sequences [2,3]. Recently, a functional link between the genome and its folding has been identified [4,5]. Homotypic clustering of long interspersed nuclear element 1 (LINE1 or L1) and B1/Alu retrotransposons forms grossly exclusive nuclear domains that characterize and predict heterochromatin and euchromatin, respectively. The spatial segregation of L1 and B1/Alu-rich compartments is conserved in mammalian cells and can be rebuilt during the cell cycle and established de novo in early embryogenesis. Inhibition of L1 RNA drastically weakened homotypic repeat contacts and compartmental segregation, indicating that L1 plays a more significant role than just being a compartmental marker. This simple and inclusive genetic coding model of L1 and B1/Alu in shaping the macroscopic structure of the genome provides a plausible explanation for the remarkable conservation and robustness of its folding in mammalian cells. It also proposes a conserved core structure on which subsequent dynamic regulation takes place.
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Affiliation(s)
- Siyang Li
- Department of Basic Medical Sciences, School of Medicine, Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaohua Shen
- Department of Basic Medical Sciences, School of Medicine, Center for Life Sciences, Tsinghua University, Beijing 100084, China.
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14
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Goychuk A, Kannan D, Chakraborty AK, Kardar M. Polymer folding through active processes recreates features of genome organization. Proc Natl Acad Sci U S A 2023; 120:e2221726120. [PMID: 37155885 PMCID: PMC10194017 DOI: 10.1073/pnas.2221726120] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Accepted: 04/02/2023] [Indexed: 05/10/2023] Open
Abstract
From proteins to chromosomes, polymers fold into specific conformations that control their biological function. Polymer folding has long been studied with equilibrium thermodynamics, yet intracellular organization and regulation involve energy-consuming, active processes. Signatures of activity have been measured in the context of chromatin motion, which shows spatial correlations and enhanced subdiffusion only in the presence of adenosine triphosphate. Moreover, chromatin motion varies with genomic coordinate, pointing toward a heterogeneous pattern of active processes along the sequence. How do such patterns of activity affect the conformation of a polymer such as chromatin? We address this question by combining analytical theory and simulations to study a polymer subjected to sequence-dependent correlated active forces. Our analysis shows that a local increase in activity (larger active forces) can cause the polymer backbone to bend and expand, while less active segments straighten out and condense. Our simulations further predict that modest activity differences can drive compartmentalization of the polymer consistent with the patterns observed in chromosome conformation capture experiments. Moreover, segments of the polymer that show correlated active (sub)diffusion attract each other through effective long-ranged harmonic interactions, whereas anticorrelations lead to effective repulsions. Thus, our theory offers nonequilibrium mechanisms for forming genomic compartments, which cannot be distinguished from affinity-based folding using structural data alone. As a first step toward exploring whether active mechanisms contribute to shaping genome conformations, we discuss a data-driven approach.
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Affiliation(s)
- Andriy Goychuk
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Deepti Kannan
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Arup K. Chakraborty
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA02139
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA02139
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA02139
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Mehran Kardar
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
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15
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Takei Y, Yang Y, White J, Yun J, Prasad M, Ombelets LJ, Schindler S, Cai L. High-resolution spatial multi-omics reveals cell-type specific nuclear compartments. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.07.539762. [PMID: 37214923 PMCID: PMC10197539 DOI: 10.1101/2023.05.07.539762] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The mammalian nucleus is compartmentalized by diverse subnuclear structures. These subnuclear structures, marked by nuclear bodies and histone modifications, are often cell-type specific and affect gene regulation and 3D genome organization1-3. Understanding nuclear organization requires identifying the molecular constituents of subnuclear structures and mapping their associations with specific genomic loci in individual cells, within complex tissues. Here, we introduce two-layer DNA seqFISH+, which allows simultaneous mapping of 100,049 genomic loci, together with nascent transcriptome for 17,856 genes and a diverse set of immunofluorescently labeled subnuclear structures all in single cells in cell lines and adult mouse cerebellum. Using these multi-omics datasets, we showed that repressive chromatin compartments are more variable by cell type than active compartments. We also discovered a single exception to this rule: an RNA polymerase II (RNAPII)-enriched compartment was associated with long, cell-type specific genes (> 200kb), in a manner distinct from nuclear speckles. Further, our analysis revealed that cell-type specific facultative and constitutive heterochromatin compartments marked by H3K27me3 and H4K20me3 are enriched at specific genes and gene clusters, respectively, and shape radial chromosomal positioning and inter-chromosomal interactions in neurons and glial cells. Together, our results provide a single-cell high-resolution multi-omics view of subnuclear compartments, associated genomic loci, and their impacts on gene regulation, directly within complex tissues.
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Affiliation(s)
- Yodai Takei
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Yujing Yang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Jonathan White
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Jina Yun
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Meera Prasad
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | | | | | - Long Cai
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
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16
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Hu Y, Stillman B. Origins of DNA replication in eukaryotes. Mol Cell 2023; 83:352-372. [PMID: 36640769 PMCID: PMC9898300 DOI: 10.1016/j.molcel.2022.12.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 01/15/2023]
Abstract
Errors occurring during DNA replication can result in inaccurate replication, incomplete replication, or re-replication, resulting in genome instability that can lead to diseases such as cancer or disorders such as autism. A great deal of progress has been made toward understanding the entire process of DNA replication in eukaryotes, including the mechanism of initiation and its control. This review focuses on the current understanding of how the origin recognition complex (ORC) contributes to determining the location of replication initiation in the multiple chromosomes within eukaryotic cells, as well as methods for mapping the location and temporal patterning of DNA replication. Origin specification and configuration vary substantially between eukaryotic species and in some cases co-evolved with gene-silencing mechanisms. We discuss the possibility that centromeres and origins of DNA replication were originally derived from a common element and later separated during evolution.
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Affiliation(s)
- Yixin Hu
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA; Program in Molecular and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Bruce Stillman
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
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17
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de Wit E, Nora EP. New insights into genome folding by loop extrusion from inducible degron technologies. Nat Rev Genet 2023; 24:73-85. [PMID: 36180596 DOI: 10.1038/s41576-022-00530-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2022] [Indexed: 01/24/2023]
Abstract
Chromatin folds into dynamic loops that often span hundreds of kilobases and physically wire distant loci together for gene regulation. These loops are continuously created, extended and positioned by structural maintenance of chromosomes (SMC) protein complexes, such as condensin and cohesin, and their regulators, including CTCF, in a highly dynamic process known as loop extrusion. Genetic loss of extrusion factors is lethal, complicating their study. Inducible protein degradation technologies enable the depletion of loop extrusion factors within hours, leading to the rapid reconfiguration of chromatin folding. Here, we review how these technologies have changed our understanding of genome organization, upsetting long-held beliefs on its role in transcription. Finally, we examine recent models that attempt to reconcile observations after chronic versus acute perturbations, and discuss future developments in this rapidly developing field of research.
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Affiliation(s)
- Elzo de Wit
- Division of Gene Regulation, Oncode Institute, Amsterdam, the Netherlands.
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Elphège P Nora
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA.
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
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18
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Guha S, Mitra MK. Multivalent binding proteins can drive collapse and reswelling of chromatin in confinement. SOFT MATTER 2022; 19:153-163. [PMID: 36484149 DOI: 10.1039/d2sm00612j] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Collapsed conformations of chromatin have been long suspected of being mediated by interactions with multivalent binding proteins, which can bring together distant sections of the chromatin fiber. In this study, we use Langevin dynamics simulation of a coarse grained chromatin polymer to show that the role of binding proteins can be more nuanced than previously suspected. In particular, for chromatin polymer in confinement, entropic forces can drive reswelling of collapsed chromatin with increasing binder concentrations, and this reswelling transition happens at physiologically relevant binder concentrations. Both the extent of collapse, and also of reswelling depends on the strength of confinement. We also study the kinetics of collapse and reswelling and show that both processes occur in similar timescales. We characterise this reswelling of chromatin in biologically relevant regimes and discuss the non-trivial role of multivalent binding proteins in mediating the spatial organisation of the genome.
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Affiliation(s)
- Sougata Guha
- Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, India.
| | - Mithun K Mitra
- Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, India.
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19
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Ibrahim Z, Wang T, Destaing O, Salvi N, Hoghoughi N, Chabert C, Rusu A, Gao J, Feletto L, Reynoird N, Schalch T, Zhao Y, Blackledge M, Khochbin S, Panne D. Structural insights into p300 regulation and acetylation-dependent genome organisation. Nat Commun 2022; 13:7759. [PMID: 36522330 PMCID: PMC9755262 DOI: 10.1038/s41467-022-35375-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
Histone modifications are deposited by chromatin modifying enzymes and read out by proteins that recognize the modified state. BRD4-NUT is an oncogenic fusion protein of the acetyl lysine reader BRD4 that binds to the acetylase p300 and enables formation of long-range intra- and interchromosomal interactions. We here examine how acetylation reading and writing enable formation of such interactions. We show that NUT contains an acidic transcriptional activation domain that binds to the TAZ2 domain of p300. We use NMR to investigate the structure of the complex and found that the TAZ2 domain has an autoinhibitory role for p300. NUT-TAZ2 interaction or mutations found in cancer that interfere with autoinhibition by TAZ2 allosterically activate p300. p300 activation results in a self-organizing, acetylation-dependent feed-forward reaction that enables long-range interactions by bromodomain multivalent acetyl-lysine binding. We discuss the implications for chromatin organisation, gene regulation and dysregulation in disease.
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Affiliation(s)
- Ziad Ibrahim
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, United States
| | - Tao Wang
- CNRS UMR 5309, INSERM U1209, Université Grenoble Alpes, Institute for Advanced Biosciences, Grenoble, France
| | - Olivier Destaing
- CNRS UMR 5309, INSERM U1209, Université Grenoble Alpes, Institute for Advanced Biosciences, Grenoble, France
| | - Nicola Salvi
- Institut de Biologie Structurale, CNRS, CEA, UGA, Grenoble, France
| | - Naghmeh Hoghoughi
- CNRS UMR 5309, INSERM U1209, Université Grenoble Alpes, Institute for Advanced Biosciences, Grenoble, France
| | - Clovis Chabert
- CNRS UMR 5309, INSERM U1209, Université Grenoble Alpes, Institute for Advanced Biosciences, Grenoble, France
| | - Alexandra Rusu
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Jinjun Gao
- Ben May Department of Cancer Research, The University of Chicago, Chicago, IL, 60637, USA
| | - Leonardo Feletto
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Nicolas Reynoird
- CNRS UMR 5309, INSERM U1209, Université Grenoble Alpes, Institute for Advanced Biosciences, Grenoble, France
| | - Thomas Schalch
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Yingming Zhao
- Ben May Department of Cancer Research, The University of Chicago, Chicago, IL, 60637, USA
| | | | - Saadi Khochbin
- CNRS UMR 5309, INSERM U1209, Université Grenoble Alpes, Institute for Advanced Biosciences, Grenoble, France
| | - Daniel Panne
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK.
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20
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Liang W, Wang S, Wang H, Li X, Meng Q, Zhao Y, Zheng C. When 3D genome technology meets viral infection, including SARS-CoV-2. J Med Virol 2022; 94:5627-5639. [PMID: 35916043 PMCID: PMC9538846 DOI: 10.1002/jmv.28040] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 07/09/2022] [Accepted: 07/30/2022] [Indexed: 01/06/2023]
Abstract
Mammalian chromosomes undergo varying degrees of compression to form three-dimensional genome structures. These three-dimensional structures undergo dynamic and precise chromatin interactions to achieve precise spatial and temporal regulation of gene expression. Most eukaryotic DNA viruses can invade their genomes into the nucleus. However, it is still poorly understood how the viral genome is precisely positioned after entering the host cell nucleus to find the most suitable location and whether it can specifically interact with the host genome to hijack the host transcriptional factories or even integrate into the host genome to complete its transcription and replication rapidly. Chromosome conformation capture technology can reveal long-range chromatin interactions between different chromosomal sites in the nucleus, potentially providing a reference for viral DNA-host chromatin interactions. This review summarized the research progress on the three-dimensional interaction between virus and host genome and the impact of virus integration into the host genome on gene transcription regulation, aiming to provide new insights into chromatin interaction and viral gene transcription regulation, laying the foundation for the treatment of infectious diseases.
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Affiliation(s)
- Weizheng Liang
- Central LaboratoryThe First Affiliated Hospital of Hebei North UniversityZhangjiakouChina
- Department of Immunology, School of Basic Medical SciencesFujian Medical UniversityFuzhouChina
| | - Shuangqing Wang
- Department of NeurologyShenzhen University General Hospital, Shenzhen UniversityShenzhen, Guangdong ProvinceChina
| | - Hao Wang
- Department of Obstetrics and GynecologyShenzhen University General HospitalShenzhen, GuangdongChina
| | - Xiushen Li
- Department of Obstetrics and GynecologyShenzhen University General HospitalShenzhen, GuangdongChina
- Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, School of Biomedical EngineeringShenzhen University Health Science CenterShenzhen, GuangdongChina
- Shenzhen Key LaboratoryShenzhen University General HospitalShenzhen, GuangdongChina
| | - Qingxue Meng
- Central LaboratoryThe First Affiliated Hospital of Hebei North UniversityZhangjiakouChina
| | - Yan Zhao
- Department of Mathematics and Computer ScienceFree University BerlinBerlinGermany
| | - Chunfu Zheng
- Department of Immunology, School of Basic Medical SciencesFujian Medical UniversityFuzhouChina
- Department of Microbiology, Immunology and Infectious DiseasesUniversity of CalgaryCalgaryAlbertaCanada
- The State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life SciencesInner Mongolia UniversityHohhotChina
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21
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Che Y, Yang X, Jia P, Wang T, Xu D, Guo T, Ye K. D 2 Plot, a Matrix of DNA Density and Distance to Periphery, Reveals Functional Genome Regions. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202149. [PMID: 36039936 PMCID: PMC9596860 DOI: 10.1002/advs.202202149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 08/09/2022] [Indexed: 06/15/2023]
Abstract
The execution of biological activities inside space-limited cell nuclei requires sophisticated organization. Current studies on the 3D genome focus on chromatin interactions and local structures, e.g., topologically associating domains (TADs). In this study, two global physical properties: DNA density and distance to nuclear periphery (DisTP), are introduced and a 2D matrix, D2 plot, is constructed for mapping genetic and epigenetic markers. Distinct patterns of functional markers on the D2 plot, indicating its ability to compartmentalize functional genome regions, are observed. Furthermore, enrichments of transcription-related markers are concatenated into a cross-species transcriptional activation model, where the nucleus is divided into four areas: active, intermediate, repress and histone, and repress and repeat. Based on the trajectories of the genomic regions on D2 plot, the constantly active and newly activated genes are successfully identified during olfactory sensory neuron maturation. The analysis reveals that the D2 plot effectively categorizes functional regions and provides a universal and transcription-related measurement for the 3D genome.
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Affiliation(s)
- Yizhuo Che
- School of Automation Science and EngineeringFaculty of Electronic and Information EngineeringXi'an Jiaotong UniversityXi'anShaanxi710049China
- MOE Key Lab for Intelligent Networks and Networks SecurityFaculty of Electronic and Information EngineeringXi'an Jiaotong UniversityXi'anShaanxi710049China
| | - Xiaofei Yang
- MOE Key Lab for Intelligent Networks and Networks SecurityFaculty of Electronic and Information EngineeringXi'an Jiaotong UniversityXi'anShaanxi710049China
- School of Computer Science and TechnologyFaculty of Electronic and Information EngineeringXi'an Jiaotong UniversityXi'anShaanxi710049China
| | - Peng Jia
- School of Automation Science and EngineeringFaculty of Electronic and Information EngineeringXi'an Jiaotong UniversityXi'anShaanxi710049China
- MOE Key Lab for Intelligent Networks and Networks SecurityFaculty of Electronic and Information EngineeringXi'an Jiaotong UniversityXi'anShaanxi710049China
| | - Tingjie Wang
- School of Automation Science and EngineeringFaculty of Electronic and Information EngineeringXi'an Jiaotong UniversityXi'anShaanxi710049China
- MOE Key Lab for Intelligent Networks and Networks SecurityFaculty of Electronic and Information EngineeringXi'an Jiaotong UniversityXi'anShaanxi710049China
| | - Dan Xu
- Key Laboratory of Biomedical Information Engineering of the Ministry of EducationSchool of Life Sciences and TechnologyXi'an Jiaotong UniversityXi'anShaanxi710049China
| | - Tianxue Guo
- School of Automation Science and EngineeringFaculty of Electronic and Information EngineeringXi'an Jiaotong UniversityXi'anShaanxi710049China
- MOE Key Lab for Intelligent Networks and Networks SecurityFaculty of Electronic and Information EngineeringXi'an Jiaotong UniversityXi'anShaanxi710049China
| | - Kai Ye
- School of Automation Science and EngineeringFaculty of Electronic and Information EngineeringXi'an Jiaotong UniversityXi'anShaanxi710049China
- MOE Key Lab for Intelligent Networks and Networks SecurityFaculty of Electronic and Information EngineeringXi'an Jiaotong UniversityXi'anShaanxi710049China
- School of Life Science and TechnologyXi'an Jiaotong UniversityXi'anShaanxi710049China
- Faculty of ScienceLeiden UniversityLeiden2300The Netherlands
- Genome InstituteThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'anShaanxi710049China
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22
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Tejedor AR, Sanchez-Burgos I, Estevez-Espinosa M, Garaizar A, Collepardo-Guevara R, Ramirez J, Espinosa JR. Protein structural transitions critically transform the network connectivity and viscoelasticity of RNA-binding protein condensates but RNA can prevent it. Nat Commun 2022; 13:5717. [PMID: 36175408 PMCID: PMC9522849 DOI: 10.1038/s41467-022-32874-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 08/18/2022] [Indexed: 12/03/2022] Open
Abstract
Biomolecular condensates, some of which are liquid-like during health, can age over time becoming gel-like pathological systems. One potential source of loss of liquid-like properties during ageing of RNA-binding protein condensates is the progressive formation of inter-protein β-sheets. To bridge microscopic understanding between accumulation of inter-protein β-sheets over time and the modulation of FUS and hnRNPA1 condensate viscoelasticity, we develop a multiscale simulation approach. Our method integrates atomistic simulations with sequence-dependent coarse-grained modelling of condensates that exhibit accumulation of inter-protein β-sheets over time. We reveal that inter-protein β-sheets notably increase condensate viscosity but does not transform the phase diagrams. Strikingly, the network of molecular connections within condensates is drastically altered, culminating in gelation when the network of strong β-sheets fully percolates. However, high concentrations of RNA decelerate the emergence of inter-protein β-sheets. Our study uncovers molecular and kinetic factors explaining how the accumulation of inter-protein β-sheets can trigger liquid-to-solid transitions in condensates, and suggests a potential mechanism to slow such transitions down. In this work the authors propose a multiscale computational approach, integrating atomistic and coarse-grained models simulations, to study the thermodynamic and kinetic factors playing a major role in the liquid-to-solid transition of biomolecular condensates. It is revealed how the gradual accumulation of inter-protein β-sheets increases the viscosity of functional liquid-like condensates, transforming them into gel-like pathological aggregates, and it is also shown how high concentrations of RNA can decelerate such transition.
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Affiliation(s)
- Andres R Tejedor
- Department of Chemical Engineering, Universidad Politécnica de Madrid, José Gutiérrez Abascal 2, 28006, Madrid, Spain.,Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Ignacio Sanchez-Burgos
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Maria Estevez-Espinosa
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK.,Department of Biochemistry, University College London, Gower Street, London, WC1E 6BT, UK
| | - Adiran Garaizar
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Rosana Collepardo-Guevara
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK.,Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.,Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK
| | - Jorge Ramirez
- Department of Chemical Engineering, Universidad Politécnica de Madrid, José Gutiérrez Abascal 2, 28006, Madrid, Spain.
| | - Jorge R Espinosa
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK.
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23
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Arroyo M, Hastert FD, Zhadan A, Schelter F, Zimbelmann S, Rausch C, Ludwig AK, Carell T, Cardoso MC. Isoform-specific and ubiquitination dependent recruitment of Tet1 to replicating heterochromatin modulates methylcytosine oxidation. Nat Commun 2022; 13:5173. [PMID: 36056023 PMCID: PMC9440122 DOI: 10.1038/s41467-022-32799-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 08/15/2022] [Indexed: 01/26/2023] Open
Abstract
Oxidation of the epigenetic DNA mark 5-methylcytosine by Tet dioxygenases is an established route to diversify the epigenetic information, modulate gene expression and overall cellular (patho-)physiology. Here, we demonstrate that Tet1 and its short isoform Tet1s exhibit distinct nuclear localization during DNA replication resulting in aberrant cytosine modification levels in human and mouse cells. We show that Tet1 is tethered away from heterochromatin via its zinc finger domain, which is missing in Tet1s allowing its targeting to these regions. We find that Tet1s interacts with and is ubiquitinated by CRL4(VprBP). The ubiquitinated Tet1s is then recognized by Uhrf1 and recruited to late replicating heterochromatin. This leads to spreading of 5-methylcytosine oxidation to heterochromatin regions, LINE 1 activation and chromatin decondensation. In summary, we elucidate a dual regulation mechanism of Tet1, contributing to the understanding of how epigenetic information can be diversified by spatio-temporal directed Tet1 catalytic activity.
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Affiliation(s)
- María Arroyo
- grid.6546.10000 0001 0940 1669Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Schnittspahnstr. 10, 64287 Darmstadt, Germany
| | - Florian D. Hastert
- grid.6546.10000 0001 0940 1669Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Schnittspahnstr. 10, 64287 Darmstadt, Germany ,grid.425396.f0000 0001 1019 0926Section AIDS and newly emerging pathogens, Paul Ehrlich Institute, Paul-Ehrlich-Str. 51-59, 63225 Langen, Germany
| | - Andreas Zhadan
- grid.6546.10000 0001 0940 1669Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Schnittspahnstr. 10, 64287 Darmstadt, Germany
| | - Florian Schelter
- grid.5252.00000 0004 1936 973XDepartment of Chemistry, Ludwig Maximilians University, Butenandstr. 5-13, 81377 Munich, Germany
| | - Susanne Zimbelmann
- grid.6546.10000 0001 0940 1669Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Schnittspahnstr. 10, 64287 Darmstadt, Germany
| | - Cathia Rausch
- grid.6546.10000 0001 0940 1669Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Schnittspahnstr. 10, 64287 Darmstadt, Germany ,grid.16008.3f0000 0001 2295 9843Present Address: Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 6, avenue du Swing, L-4367 Belvaux, Luxembourg
| | - Anne K. Ludwig
- grid.6546.10000 0001 0940 1669Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Schnittspahnstr. 10, 64287 Darmstadt, Germany ,grid.5253.10000 0001 0328 4908Present Address: Department of Medicine, Hematology, Oncology and Rheumatology, University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Thomas Carell
- grid.5252.00000 0004 1936 973XDepartment of Chemistry, Ludwig Maximilians University, Butenandstr. 5-13, 81377 Munich, Germany
| | - M. Cristina Cardoso
- grid.6546.10000 0001 0940 1669Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, Schnittspahnstr. 10, 64287 Darmstadt, Germany
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24
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Singh PB, Newman AG. HP1-Driven Micro-Phase Separation of Heterochromatin-Like Domains/Complexes. Epigenet Insights 2022; 15:25168657221109766. [PMID: 35813402 PMCID: PMC9260563 DOI: 10.1177/25168657221109766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 06/08/2022] [Indexed: 11/18/2022] Open
Affiliation(s)
- Prim B Singh
- Department of Medicine, Nazarbayev University School of Medicine, Nur-Sultan, Kazakhstan
| | - Andrew G Newman
- Institute of Cell and Neurobiology, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
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25
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Yildirim A, Boninsegna L, Zhan Y, Alber F. Uncovering the Principles of Genome Folding by 3D Chromatin Modeling. Cold Spring Harb Perspect Biol 2022; 14:a039693. [PMID: 34400556 PMCID: PMC9248826 DOI: 10.1101/cshperspect.a039693] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Our understanding of how genomic DNA is tightly packed inside the nucleus, yet is still accessible for vital cellular processes, has grown dramatically over recent years with advances in microscopy and genomics technologies. Computational methods have played a pivotal role in the structural interpretation of experimental data, which helped unravel some organizational principles of genome folding. Here, we give an overview of current computational efforts in mechanistic and data-driven 3D chromatin structure modeling. We discuss strengths and limitations of different methods and evaluate the added value and benefits of computational approaches to infer the 3D structural and dynamic properties of the genome and its underlying mechanisms at different scales and resolution, ranging from the dynamic formation of chromatin loops and topological associated domains to nuclear compartmentalization of chromatin and nuclear bodies.
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Affiliation(s)
- Asli Yildirim
- Institute for Quantitative and Computational Biosciences, Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Lorenzo Boninsegna
- Institute for Quantitative and Computational Biosciences, Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Yuxiang Zhan
- Institute for Quantitative and Computational Biosciences, Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California 90095, USA
- Quantitative and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
| | - Frank Alber
- Institute for Quantitative and Computational Biosciences, Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California 90095, USA
- Quantitative and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, USA
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26
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Epigenetic Studies for Evaluation of NPS Toxicity: Focus on Synthetic Cannabinoids and Cathinones. Biomedicines 2022; 10:biomedicines10061398. [PMID: 35740419 PMCID: PMC9219842 DOI: 10.3390/biomedicines10061398] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/02/2022] [Accepted: 06/06/2022] [Indexed: 11/26/2022] Open
Abstract
In the recent decade, numerous new psychoactive substances (NPSs) have been added to the illicit drug market. These are synthetized to mimic the effects of classic drugs of abuse (i.e., cannabis, cocaine, etc.), with the purpose of bypassing substance legislations and increasing the pharmacotoxicological effects. To date, research into the acute pharmacological effects of new NPSs is ongoing and necessary in order to provide an appropriate contribution to public health. In fact, multiple examples of NPS-related acute intoxication and mortality have been recorded in the literature. Accordingly, several in vitro and in vivo studies have investigated the pharmacotoxicological profiles of these compounds, revealing that they can cause adverse effects involving various organ systems (i.e., cardiovascular, respiratory effects) and highlighting their potential increased consumption risks. In this sense, NPSs should be regarded as a complex issue that requires continuous monitoring. Moreover, knowledge of long-term NPS effects is lacking. Because genetic and environmental variables may impact NPS responses, epigenetics may aid in understanding the processes behind the harmful events induced by long-term NPS usage. Taken together, “pharmacoepigenomics” may provide a new field of combined study on genetic differences and epigenetic changes in drug reactions that might be predictive in forensic implications.
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27
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Nde1 is Required for Heterochromatin Compaction and Stability in Neocortical Neurons. iScience 2022; 25:104354. [PMID: 35601919 PMCID: PMC9121328 DOI: 10.1016/j.isci.2022.104354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 03/28/2022] [Accepted: 04/29/2022] [Indexed: 11/20/2022] Open
Abstract
The NDE1 gene encodes a scaffold protein essential for brain development. Although biallelic NDE1 loss of function (LOF) causes microcephaly with profound mental retardation, NDE1 missense mutations and copy number variations are associated with multiple neuropsychiatric disorders. However, the etiology of the diverse phenotypes resulting from NDE1 aberrations remains elusive. Here we demonstrate Nde1 controls neurogenesis through facilitating H4K20 trimethylation-mediated heterochromatin compaction. This mechanism patterns diverse chromatin landscapes and stabilizes constitutive heterochromatin of neocortical neurons. We demonstrate that NDE1 can undergo dynamic liquid-liquid phase separation, partitioning to the nucleus and interacting with pericentromeric and centromeric satellite repeats. Nde1 LOF results in nuclear architecture aberrations and DNA double-strand breaks, as well as instability and derepression of pericentromeric satellite repeats in neocortical neurons. These findings uncover a pivotal role of NDE1/Nde1 in establishing and protecting neuronal heterochromatin. They suggest that heterochromatin instability predisposes a wide range of brain dysfunction. Cortical neurogenesis is coupled with heterochromatin compaction marked by H4K20me3 Nde1 undergoes liquid-liquid phase separation and interacts with heterochromatin Nde1 mutations impair H4K20me3 during neural progenitor differentiation Neurons lacking Nde1 derepress heterochromatin and lose nuclear and genomic integrity
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28
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Chu W, Chu X, Wang J. Uncovering the Quantitative Relationships Among Chromosome Fluctuations, Epigenetics, and Gene Expressions of Transdifferentiation on Waddington Landscape. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2103617. [PMID: 35104056 PMCID: PMC8981899 DOI: 10.1002/advs.202103617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 12/21/2021] [Indexed: 06/14/2023]
Abstract
The 3D spatial organization of the chromosomes appears to be linked to the gene function, which is cell type-specific. The chromosome structural ensemble switching model (CSESM) is developed by employing a heteropolymer model on different cell types and the important quantitative relationships among the chromosome ensemble, the epigenetic marks, and the gene expressions are uncovered, that both chromosome fluctuation and epigenetic marks have strong linear correlations with the gene expressions. The results support that the two compartments have different behaviors, corresponding to the relatively sparse and fluctuating phase (compartment A) and the relatively dense and stable phase (compartment B). Importantly, through the investigation of the transdifferentiation processes between the peripheral blood mononuclear cell (PBMC) and the bipolar neuron (BN), a quantitative description for the transdifferentiation is provided, which can be linked to the Waddington landscape. In addition, compared to the direct transdifferentiation between PBMC and BN, the transdifferentiation via the intermediate state neural progenitor cell (NPC) follows a different path (an "uphill" followed by a "downhill"). These theoretical studies bridge the gap among the chromosome fluctuations/ensembles, the epigenetics, and gene expressions in determining the cell fate.
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Affiliation(s)
- Wen‐Ting Chu
- State Key Laboratory of Electroanalytical ChemistryChangchun Institute of Applied ChemistryChinese Academy of SciencesChangchunJilin130022China
| | - Xiakun Chu
- Department of Chemistry & PhysicsState University of New York at Stony BrookStony BrookNY11794USA
| | - Jin Wang
- Department of Chemistry & PhysicsState University of New York at Stony BrookStony BrookNY11794USA
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29
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Chang L, Li M, Shao S, Li C, Ai S, Xue B, Hou Y, Zhang Y, Li R, Fan X, He A, Li C, Sun Y. Nuclear peripheral chromatin-lamin B1 interaction is required for global integrity of chromatin architecture and dynamics in human cells. Protein Cell 2022; 13:258-280. [PMID: 33155082 PMCID: PMC8934373 DOI: 10.1007/s13238-020-00794-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/07/2020] [Indexed: 12/14/2022] Open
Abstract
The eukaryotic genome is folded into higher-order conformation accompanied with constrained dynamics for coordinated genome functions. However, the molecular machinery underlying these hierarchically organized three-dimensional (3D) chromatin architecture and dynamics remains poorly understood. Here by combining imaging and sequencing, we studied the role of lamin B1 in chromatin architecture and dynamics. We found that lamin B1 depletion leads to detachment of lamina-associated domains (LADs) from the nuclear periphery accompanied with global chromatin redistribution and decompaction. Consequently, the inter-chromosomal as well as inter-compartment interactions are increased, but the structure of topologically associating domains (TADs) is not affected. Using live-cell genomic loci tracking, we further proved that depletion of lamin B1 leads to increased chromatin dynamics, owing to chromatin decompaction and redistribution toward nucleoplasm. Taken together, our data suggest that lamin B1 and chromatin interactions at the nuclear periphery promote LAD maintenance, chromatin compaction, genomic compartmentalization into chromosome territories and A/B compartments and confine chromatin dynamics, supporting their crucial roles in chromatin higher-order structure and chromatin dynamics.
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Affiliation(s)
- Lei Chang
- State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871 China
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, 510530 China
| | - Mengfan Li
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871 China
- Center for Bioinformatics, School of Life Sciences, Peking University, Beijing, 100871 China
| | - Shipeng Shao
- State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871 China
| | - Chen Li
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, 100871 China
| | - Shanshan Ai
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, 100871 China
| | - Boxin Xue
- State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871 China
| | - Yingping Hou
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871 China
- Center for Bioinformatics, School of Life Sciences, Peking University, Beijing, 100871 China
| | - Yiwen Zhang
- State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871 China
| | - Ruifeng Li
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871 China
- Center for Bioinformatics, School of Life Sciences, Peking University, Beijing, 100871 China
| | - Xiaoying Fan
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, 510530 China
| | - Aibin He
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871 China
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, 100871 China
| | - Cheng Li
- Center for Bioinformatics, School of Life Sciences, Peking University, Beijing, 100871 China
- Center for Statistical Science, Peking University, Beijing, 100871 China
| | - Yujie Sun
- State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871 China
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30
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Zakirov AN, Sosnovskaya S, Ryumina ED, Kharybina E, Strelkova OS, Zhironkina OA, Golyshev SA, Moiseenko A, Kireev II. Fiber-Like Organization as a Basic Principle for Euchromatin Higher-Order Structure. Front Cell Dev Biol 2022; 9:784440. [PMID: 35174159 PMCID: PMC8841976 DOI: 10.3389/fcell.2021.784440] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/23/2021] [Indexed: 11/13/2022] Open
Abstract
A detailed understanding of the principles of the structural organization of genetic material is of great importance for elucidating the mechanisms of differential regulation of genes in development. Modern ideas about the spatial organization of the genome are based on a microscopic analysis of chromatin structure and molecular data on DNA–DNA contact analysis using Chromatin conformation capture (3C) technology, ranging from the “polymer melt” model to a hierarchical folding concept. Heterogeneity of chromatin structure depending on its functional state and cell cycle progression brings another layer of complexity to the interpretation of structural data and requires selective labeling of various transcriptional states under nondestructive conditions. Here, we use a modified approach for replication timing-based metabolic labeling of transcriptionally active chromatin for ultrastructural analysis. The method allows pre-embedding labeling of optimally structurally preserved chromatin, thus making it compatible with various 3D-TEM techniques including electron tomography. By using variable pulse duration, we demonstrate that euchromatic genomic regions adopt a fiber-like higher-order structure of about 200 nm in diameter (chromonema), thus providing support for a hierarchical folding model of chromatin organization as well as the idea of transcription and replication occurring on a highly structured chromatin template.
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Affiliation(s)
- Amir N Zakirov
- Department of Electron Microscopy, AN. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,Chair of Cell Biology and Histology, Biology Faculty, Lomonosov Moscow State University, Moscow, Russia
| | - Sophie Sosnovskaya
- Department of Electron Microscopy, AN. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,Chair of Cell Biology and Histology, Biology Faculty, Lomonosov Moscow State University, Moscow, Russia
| | - Ekaterina D Ryumina
- Department of Electron Microscopy, AN. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
| | - Ekaterina Kharybina
- Department of Electron Microscopy, AN. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,Chair of Cell Biology and Histology, Biology Faculty, Lomonosov Moscow State University, Moscow, Russia
| | - Olga S Strelkova
- Department of Electron Microscopy, AN. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Oxana A Zhironkina
- Department of Electron Microscopy, AN. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Sergei A Golyshev
- Department of Electron Microscopy, AN. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Andrey Moiseenko
- Laboratory of Electron Microscopy, Biology Faculty, Lomonosov Moscow State University, Moscow, Russia
| | - Igor I Kireev
- Department of Electron Microscopy, AN. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,Chair of Cell Biology and Histology, Biology Faculty, Lomonosov Moscow State University, Moscow, Russia
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31
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Leidescher S, Ribisel J, Ullrich S, Feodorova Y, Hildebrand E, Galitsyna A, Bultmann S, Link S, Thanisch K, Mulholland C, Dekker J, Leonhardt H, Mirny L, Solovei I. Spatial organization of transcribed eukaryotic genes. Nat Cell Biol 2022; 24:327-339. [PMID: 35177821 DOI: 10.1038/s41556-022-00847-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 01/10/2022] [Indexed: 12/19/2022]
Abstract
Despite the well-established role of nuclear organization in the regulation of gene expression, little is known about the reverse: how transcription shapes the spatial organization of the genome. Owing to the small sizes of most previously studied genes and the limited resolution of microscopy, the structure and spatial arrangement of a single transcribed gene are still poorly understood. Here we study several long highly expressed genes and demonstrate that they form open-ended transcription loops with polymerases moving along the loops and carrying nascent RNAs. Transcription loops can span across micrometres, resembling lampbrush loops and polytene puffs. The extension and shape of transcription loops suggest their intrinsic stiffness, which we attribute to decoration with multiple voluminous nascent ribonucleoproteins. Our data contradict the model of transcription factories and suggest that although microscopically resolvable transcription loops are specific for long highly expressed genes, the mechanisms underlying their formation could represent a general aspect of eukaryotic transcription.
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Affiliation(s)
- Susanne Leidescher
- Department of Biology II, Biozentrum, Ludwig-Maximilians University Munich (LMU), Planegg-Martinsried, Germany
| | - Johannes Ribisel
- Institute for Medical Engineering and Science, and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Simon Ullrich
- Department of Biology II, Biozentrum, Ludwig-Maximilians University Munich (LMU), Planegg-Martinsried, Germany
| | - Yana Feodorova
- Department of Biology II, Biozentrum, Ludwig-Maximilians University Munich (LMU), Planegg-Martinsried, Germany.,Department of Medical Biology, Medical University of Plovdiv; Division of Molecular and Regenerative Medicine, Research Institute at Medical University of Plovdiv, Plovdiv, Bulgaria
| | - Erica Hildebrand
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
| | | | - Sebastian Bultmann
- Department of Biology II, Biozentrum, Ludwig-Maximilians University Munich (LMU), Planegg-Martinsried, Germany
| | - Stephanie Link
- BioMedizinisches Center, Ludwig-Maximilians University Munich, Planegg-Martinsried, Germany
| | - Katharina Thanisch
- Department of Biology II, Biozentrum, Ludwig-Maximilians University Munich (LMU), Planegg-Martinsried, Germany.,Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Christopher Mulholland
- Department of Biology II, Biozentrum, Ludwig-Maximilians University Munich (LMU), Planegg-Martinsried, Germany
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Heinrich Leonhardt
- Department of Biology II, Biozentrum, Ludwig-Maximilians University Munich (LMU), Planegg-Martinsried, Germany
| | - Leonid Mirny
- Institute for Medical Engineering and Science, and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Irina Solovei
- Department of Biology II, Biozentrum, Ludwig-Maximilians University Munich (LMU), Planegg-Martinsried, Germany.
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32
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Zhang H, Romero H, Schmidt A, Gagova K, Qin W, Bertulat B, Lehmkuhl A, Milden M, Eck M, Meckel T, Leonhardt H, Cardoso MC. MeCP2-induced heterochromatin organization is driven by oligomerization-based liquid–liquid phase separation and restricted by DNA methylation. Nucleus 2022; 13:1-34. [PMID: 35156529 PMCID: PMC8855868 DOI: 10.1080/19491034.2021.2024691] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Hui Zhang
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Hector Romero
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Annika Schmidt
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Katalina Gagova
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Weihua Qin
- Faculty of Biology, Ludwig Maximilians University Munich, Munich, Germany
| | - Bianca Bertulat
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Anne Lehmkuhl
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Manuela Milden
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Malte Eck
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Tobias Meckel
- Department of Chemistry, Technical University of Darmstadt, Darmstadt, Germany
| | - Heinrich Leonhardt
- Faculty of Biology, Ludwig Maximilians University Munich, Munich, Germany
| | - M. Cristina Cardoso
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
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33
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Brändle F, Frühbauer B, Jagannathan M. Principles and functions of pericentromeric satellite DNA clustering into chromocenters. Semin Cell Dev Biol 2022; 128:26-39. [PMID: 35144860 DOI: 10.1016/j.semcdb.2022.02.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/03/2022] [Accepted: 02/03/2022] [Indexed: 12/29/2022]
Abstract
Simple non-coding tandem repeats known as satellite DNA are observed widely across eukaryotes. These repeats occupy vast regions at the centromere and pericentromere of chromosomes but their contribution to cellular function has remained incompletely understood. Here, we review the literature on pericentromeric satellite DNA and discuss its organization and functions across eukaryotic species. We specifically focus on chromocenters, DNA-dense nuclear foci that contain clustered pericentromeric satellite DNA repeats from multiple chromosomes. We first discuss chromocenter formation and the roles that epigenetic modifications, satellite DNA transcripts and sequence-specific satellite DNA-binding play in this process. We then review the newly emerging functions of chromocenters in genome encapsulation, the maintenance of cell fate and speciation. We specifically highlight how the rapid divergence of satellite DNA repeats impacts reproductive isolation between closely related species. Together, we underline the importance of this so-called 'junk DNA' in fundamental biological processes.
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Affiliation(s)
- Franziska Brändle
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, Zürich CH-8093, Switzerland
| | - Benjamin Frühbauer
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, Zürich CH-8093, Switzerland
| | - Madhav Jagannathan
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, Zürich CH-8093, Switzerland.
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34
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Ceschi S, Berselli M, Cozzaglio M, Giantin M, Toppo S, Spolaore B, Sissi C. Vimentin binds to G-quadruplex repeats found at telomeres and gene promoters. Nucleic Acids Res 2022; 50:1370-1381. [PMID: 35100428 PMCID: PMC8860586 DOI: 10.1093/nar/gkab1274] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 11/22/2021] [Accepted: 01/24/2022] [Indexed: 11/15/2022] Open
Abstract
G-quadruplex (G4) structures that can form at guanine-rich genomic sites, including telomeres and gene promoters, are actively involved in genome maintenance, replication, and transcription, through finely tuned interactions with protein networks. In the present study, we identified the intermediate filament protein Vimentin as a binder with nanomolar affinity for those G-rich sequences that give rise to at least two adjacent G4 units, named G4 repeats. This interaction is supported by the N-terminal domains of soluble Vimentin tetramers. The selectivity of Vimentin for G4 repeats versus individual G4s provides an unprecedented result. Based on GO enrichment analysis performed on genes having putative G4 repeats within their core promoters, we suggest that Vimentin recruitment at these sites may contribute to the regulation of gene expression during cell development and migration, possibly by reshaping the local higher-order genome topology, as already reported for lamin B.
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Affiliation(s)
- Silvia Ceschi
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova 35131, Italy
| | - Michele Berselli
- Department of Molecular Medicine, University of Padova, Padova 35131, Italy
| | - Marta Cozzaglio
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova 35131, Italy
| | - Mery Giantin
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro 35020, Italy
| | - Stefano Toppo
- CRIBI Biotechnology Center (Centro di Ricerca Interdipartimentale per le Biotecnologie Innovative), University of Padova, Padova 35131, Italy
- Department of Molecular Medicine, University of Padova, Padova 35131, Italy
| | - Barbara Spolaore
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova 35131, Italy
- CRIBI Biotechnology Center (Centro di Ricerca Interdipartimentale per le Biotecnologie Innovative), University of Padova, Padova 35131, Italy
| | - Claudia Sissi
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova 35131, Italy
- CRIBI Biotechnology Center (Centro di Ricerca Interdipartimentale per le Biotecnologie Innovative), University of Padova, Padova 35131, Italy
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35
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Eisenstecken T, Winkler RG. Path integral description of semiflexible active Brownian polymers. J Chem Phys 2022; 156:064105. [DOI: 10.1063/5.0081020] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Roland G. Winkler
- Institute for Advanced Simulation, Forschungszentrum Jülich, Germany
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36
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Das R, Sakaue T, Shivashankar GV, Prost J, Hiraiwa T. How enzymatic activity is involved in chromatin organization. eLife 2022; 11:79901. [PMID: 36472500 PMCID: PMC9810329 DOI: 10.7554/elife.79901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 12/06/2022] [Indexed: 12/12/2022] Open
Abstract
Spatial organization of chromatin plays a critical role in genome regulation. Previously, various types of affinity mediators and enzymes have been attributed to regulate spatial organization of chromatin from a thermodynamics perspective. However, at the mechanistic level, enzymes act in their unique ways and perturb the chromatin. Here, we construct a polymer physics model following the mechanistic scheme of Topoisomerase-II, an enzyme resolving topological constraints of chromatin, and investigate how it affects interphase chromatin organization. Our computer simulations demonstrate Topoisomerase-II's ability to phase separate chromatin into eu- and heterochromatic regions with a characteristic wall-like organization of the euchromatic regions. We realized that the ability of the euchromatic regions to cross each other due to enzymatic activity of Topoisomerase-II induces this phase separation. This realization is based on the physical fact that partial absence of self-avoiding interaction can induce phase separation of a system into its self-avoiding and non-self-avoiding parts, which we reveal using a mean-field argument. Furthermore, motivated from recent experimental observations, we extend our model to a bidisperse setting and show that the characteristic features of the enzymatic activity-driven phase separation survive there. The existence of these robust characteristic features, even under the non-localized action of the enzyme, highlights the critical role of enzymatic activity in chromatin organization.
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Affiliation(s)
- Rakesh Das
- Mechanobiology Institute, National University of SingaporeSingaporeSingapore
| | - Takahiro Sakaue
- Department of Physics and Mathematics, Aoyama Gakuin UniversityKanagawaJapan
| | - GV Shivashankar
- ETH ZurichZurichSwitzerland,Paul Scherrer InstituteVilligenSwitzerland
| | - Jacques Prost
- Mechanobiology Institute, National University of SingaporeSingaporeSingapore,Laboratoire Physico Chimie Curie, Institut Curie, Paris Science et Lettres Research UniversityParisFrance
| | - Tetsuya Hiraiwa
- Mechanobiology Institute, National University of SingaporeSingaporeSingapore
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37
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Castells-Garcia A, Ed-Daoui I, González-Almela E, Vicario C, Ottestrom J, Lakadamyali M, Neguembor MV, Cosma MP. Super resolution microscopy reveals how elongating RNA polymerase II and nascent RNA interact with nucleosome clutches. Nucleic Acids Res 2021; 50:175-190. [PMID: 34929735 PMCID: PMC8754629 DOI: 10.1093/nar/gkab1215] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 10/13/2021] [Accepted: 11/26/2021] [Indexed: 11/17/2022] Open
Abstract
Transcription and genome architecture are interdependent, but it is still unclear how nucleosomes in the chromatin fiber interact with nascent RNA, and which is the relative nuclear distribution of these RNAs and elongating RNA polymerase II (RNAP II). Using super-resolution (SR) microscopy, we visualized the nascent transcriptome, in both nucleoplasm and nucleolus, with nanoscale resolution. We found that nascent RNAs organize in structures we termed RNA nanodomains, whose characteristics are independent of the number of transcripts produced over time. Dual-color SR imaging of nascent RNAs, together with elongating RNAP II and H2B, shows the physical relation between nucleosome clutches, RNAP II, and RNA nanodomains. The distance between nucleosome clutches and RNA nanodomains is larger than the distance measured between elongating RNAP II and RNA nanodomains. Elongating RNAP II stands between nascent RNAs and the small, transcriptionally active, nucleosome clutches. Moreover, RNA factories are small and largely formed by few RNAP II. Finally, we describe a novel approach to quantify the transcriptional activity at an individual gene locus. By measuring local nascent RNA accumulation upon transcriptional activation at single alleles, we confirm the measurements made at the global nuclear level.
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Affiliation(s)
- Alvaro Castells-Garcia
- Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China
| | - Ilyas Ed-Daoui
- CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
| | - Esther González-Almela
- Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China
| | - Chiara Vicario
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Jason Ottestrom
- ICFO-Institute of Photonic Sciences, The Barcelona Institute of Science and Technology, Barcelona, 08860, Spain
| | - Melike Lakadamyali
- Perelman School of Medicine, Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA.,Perelman School of Medicine, Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Maria Victoria Neguembor
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Maria Pia Cosma
- Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China.,CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.,Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain.,ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Dr Aiguader 88, 08003 Barcelona, Spain
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38
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Boninsegna L, Yildirim A, Zhan Y, Alber F. Integrative approaches in genome structure analysis. Structure 2021; 30:24-36. [PMID: 34963059 DOI: 10.1016/j.str.2021.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/13/2021] [Accepted: 12/01/2021] [Indexed: 12/17/2022]
Abstract
New technological advances in integrated imaging, sequencing-based assays, and computational analysis have revolutionized our view of genomes in terms of their structure and dynamics in space and time. These advances promise a deeper understanding of genome functions and mechanistic insights into how the nucleus is spatially organized and functions. These wide arrays of complementary data provide an opportunity to produce quantitative integrative models of nuclear organization. In this article, we highlight recent key developments and discuss the outlook for these fields.
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Affiliation(s)
- Lorenzo Boninsegna
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Asli Yildirim
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Yuxiang Zhan
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Frank Alber
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA.
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39
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Daghsni M, Aldiri I. Building a Mammalian Retina: An Eye on Chromatin Structure. Front Genet 2021; 12:775205. [PMID: 34764989 PMCID: PMC8576187 DOI: 10.3389/fgene.2021.775205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 10/08/2021] [Indexed: 11/13/2022] Open
Abstract
Regulation of gene expression by chromatin structure has been under intensive investigation, establishing nuclear organization and genome architecture as a potent and effective means of regulating developmental processes. The substantial growth in our knowledge of the molecular mechanisms underlying retinogenesis has been powered by several genome-wide based tools that mapped chromatin organization at multiple cellular and biochemical levels. Studies profiling the retinal epigenome and transcriptome have allowed the systematic annotation of putative cis-regulatory elements associated with transcriptional programs that drive retinal neural differentiation, laying the groundwork to understand spatiotemporal retinal gene regulation at a mechanistic level. In this review, we outline recent advances in our understanding of the chromatin architecture in the mammalian retina during development and disease. We focus on the emerging roles of non-coding regulatory elements in controlling retinal cell-type specific transcriptional programs, and discuss potential implications in untangling the etiology of eye-related disorders.
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Affiliation(s)
- Marwa Daghsni
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Issam Aldiri
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Developmental Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, United States
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40
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Park SH, Kim SJ, Myung K, Lee KY. Characterization of subcellular localization of eukaryotic clamp loader/unloader and its regulatory mechanism. Sci Rep 2021; 11:21817. [PMID: 34751190 PMCID: PMC8575788 DOI: 10.1038/s41598-021-01336-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 10/13/2021] [Indexed: 11/27/2022] Open
Abstract
Proliferating cell nuclear antigen (PCNA) plays a critical role as a processivity clamp for eukaryotic DNA polymerases and a binding platform for many DNA replication and repair proteins. The enzymatic activities of PCNA loading and unloading have been studied extensively in vitro. However, the subcellular locations of PCNA loaders, replication complex C (RFC) and CTF18-RFC-like-complex (RLC), and PCNA unloader ATAD5-RLC remain elusive, and the role of their subunits RFC2-5 is unknown. Here we used protein fractionation to determine the subcellular localization of RFC and RLCs and affinity purification to find molecular requirements for the newly defined location. All RFC/RLC proteins were detected in the nuclease-resistant pellet fraction. RFC1 and ATAD5 were not detected in the non-ionic detergent-soluble and nuclease-susceptible chromatin fractions, independent of cell cycle or exogenous DNA damage. We found that small RFC proteins contribute to maintaining protein levels of the RFC/RLCs. RFC1, ATAD5, and RFC4 co-immunoprecipitated with lamina-associated polypeptide 2 (LAP2) α which regulates intranuclear lamin A/C. LAP2α knockout consistently reduced detection of RFC/RLCs in the pellet fraction, while marginally affecting total protein levels. Our findings strongly suggest that PCNA-mediated DNA transaction occurs through regulatory machinery associated with nuclear structures, such as the nuclear matrix.
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Affiliation(s)
- Su Hyung Park
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, 44919, Korea
| | - Seong-Jung Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, 44919, Korea.,Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, 44919, Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, 44919, Korea.,Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, Korea
| | - Kyoo-Young Lee
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, 44919, Korea.
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41
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Mirny L, Dekker J. Mechanisms of Chromosome Folding and Nuclear Organization: Their Interplay and Open Questions. Cold Spring Harb Perspect Biol 2021; 14:cshperspect.a040147. [DOI: 10.1101/cshperspect.a040147] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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42
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Mousavi SM, Gompper G, Winkler RG. Active bath-induced localization and collapse of passive semiflexible polymers. J Chem Phys 2021; 155:044902. [PMID: 34340385 DOI: 10.1063/5.0058150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The conformational and dynamical properties of a passive polymer embedded in a bath of active Brownian particles (ABPs) are studied by Langevin dynamics simulations. Various activities and ABP concentrations below and above the critical values for motility-induced phase separation (MIPS) are considered. In a homogeneous ABP fluid, the embedded polymer swells with increasing bath activity, with stronger swelling for larger densities. The polymer dynamics is enhanced, with the diffusion coefficient increasing by a power-law with increasing activity, where the exponent depends on the ABP concentration. For ABP concentrations in the MIPS regime, we observe a localization of the polymer in the low-density ABP phase associated with polymer collapse for moderate activities and a reswelling for high activities accompanied by a preferred localization in the high-density ABP phase. Localization and reswelling are independent of the polymer stiffness, with stiff polymers behaving similarly to flexible polymers. The polymer collapse is associated with a slowdown of its dynamics and a significantly smaller center-of-mass diffusion coefficient. In general, the polymer dynamics can only partially be described by an effective (bath) temperature. Moreover, the properties of a polymer embedded in a homogeneous active bath deviate quantitatively from those of a polymer composed of active monomers, i.e., linear chains of ABPs; however, such a polymer exhibits qualitatively similar activity-dependent features.
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Affiliation(s)
- S Mahdiyeh Mousavi
- Theoretical Physics of Living Matter, Institute for Advanced Simulation and Institute of Biological Information Processing, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Gerhard Gompper
- Theoretical Physics of Living Matter, Institute for Advanced Simulation and Institute of Biological Information Processing, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Roland G Winkler
- Theoretical Physics of Living Matter, Institute for Advanced Simulation and Institute of Biological Information Processing, Forschungszentrum Jülich, D-52425 Jülich, Germany
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43
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Ravel-Godreuil C, Massiani-Beaudoin O, Mailly P, Prochiantz A, Joshi RL, Fuchs J. Perturbed DNA methylation by Gadd45b induces chromatin disorganization, DNA strand breaks and dopaminergic neuron death. iScience 2021; 24:102756. [PMID: 34278264 PMCID: PMC8264156 DOI: 10.1016/j.isci.2021.102756] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 05/14/2021] [Accepted: 06/17/2021] [Indexed: 12/13/2022] Open
Abstract
Age is a major risk factor for neurodegenerative diseases like Parkinson's disease, but few studies have explored the contribution of key hallmarks of aging, namely DNA methylation changes and heterochromatin destructuration, in the neurodegenerative process. Here, we investigated the consequences of viral overexpression of Gadd45b, a multifactorial protein involved in DNA demethylation, in the mouse midbrain. Gadd45b overexpression induced global and stable changes in DNA methylation, particularly in introns of genes related to neuronal functions, as well as on LINE-1 transposable elements. This was paralleled by disorganized heterochromatin, increased DNA damage, and vulnerability to oxidative stress. LINE-1 de-repression, a potential source of DNA damage, preceded Gadd45b-induced neurodegeneration, whereas prolonged Gadd45b expression deregulated expression of genes related to heterochromatin maintenance, DNA methylation, or Parkinson's disease. Our data indicates that aging-related alterations contribute to dopaminergic neuron degeneration with potential implications for Parkinson's disease.
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Affiliation(s)
- Camille Ravel-Godreuil
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Olivia Massiani-Beaudoin
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Philippe Mailly
- Orion Imaging Facility, Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
| | - Alain Prochiantz
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Rajiv L. Joshi
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Julia Fuchs
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
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44
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Karamysheva T, Romanenko S, Makunin A, Rajičić M, Bogdanov A, Trifonov V, Blagojević J, Vujošević M, Orishchenko K, Rubtsov N. New Data on Organization and Spatial Localization of B-Chromosomes in Cell Nuclei of the Yellow-Necked Mouse Apodemus flavicollis. Cells 2021; 10:cells10071819. [PMID: 34359988 PMCID: PMC8305704 DOI: 10.3390/cells10071819] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 11/17/2022] Open
Abstract
The gene composition, function and evolution of B-chromosomes (Bs) have been actively discussed in recent years. However, the additional genomic elements are still enigmatic. One of Bs mysteries is their spatial organization in the interphase nucleus. It is known that heterochromatic compartments are not randomly localized in a nucleus. The purpose of this work was to study the organization and three-dimensional spatial arrangement of Bs in the interphase nucleus. Using microdissection of Bs and autosome centromeric heterochromatic regions of the yellow-necked mouse (Apodemus flavicollis) we obtained DNA probes for further two-dimensional (2D)- and three-dimensional (3D)- fluorescence in situ hybridization (FISH) studies. Simultaneous in situ hybridization of obtained here B-specific DNA probes and autosomal C-positive pericentromeric region-specific probes further corroborated the previously stated hypothesis about the pseudoautosomal origin of the additional chromosomes of this species. Analysis of the spatial organization of the Bs demonstrated the peripheral location of B-specific chromatin within the interphase nucleus and feasible contact with the nuclear envelope (similarly to pericentromeric regions of autosomes and sex chromosomes). It is assumed that such interaction is essential for the regulation of nuclear architecture. It also points out that Bs may follow the same mechanism as sex chromosomes to avoid a meiotic checkpoint.
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Affiliation(s)
- Tatyana Karamysheva
- Institute of Cytology and Genetics, The Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (K.O.); (N.R.)
- Correspondence: ; Tel.: +7-(383)-363-4963 (ext. 1332)
| | - Svetlana Romanenko
- Institute of Molecular and Cellular Biology, The Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (S.R.); (V.T.)
| | | | - Marija Rajičić
- Institute for Biological Research “Siniša Stanković”, National Institute of Republic of Serbia, 11060 Belgrade, Serbia; (M.R.); (J.B.); (M.V.)
| | - Alexey Bogdanov
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 119991 Moscow, Russia;
| | - Vladimir Trifonov
- Institute of Molecular and Cellular Biology, The Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (S.R.); (V.T.)
- Department of Genetic Technologies, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Jelena Blagojević
- Institute for Biological Research “Siniša Stanković”, National Institute of Republic of Serbia, 11060 Belgrade, Serbia; (M.R.); (J.B.); (M.V.)
| | - Mladen Vujošević
- Institute for Biological Research “Siniša Stanković”, National Institute of Republic of Serbia, 11060 Belgrade, Serbia; (M.R.); (J.B.); (M.V.)
| | - Konstantin Orishchenko
- Institute of Cytology and Genetics, The Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (K.O.); (N.R.)
- Department of Genetic Technologies, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Nikolay Rubtsov
- Institute of Cytology and Genetics, The Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (K.O.); (N.R.)
- Department of Genetic Technologies, Novosibirsk State University, 630090 Novosibirsk, Russia
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45
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Perez BS, Wong KM, Schwartz EK, Herrera RE, King DA, García-Nieto PE, Morrison AJ. Genome-wide profiles of UV lesion susceptibility, repair, and mutagenic potential in melanoma. Mutat Res 2021; 823:111758. [PMID: 34333390 PMCID: PMC8671223 DOI: 10.1016/j.mrfmmm.2021.111758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 07/14/2021] [Indexed: 10/20/2022]
Abstract
Exposure to the ultraviolet (UV) radiation in sunlight creates DNA lesions, which if left unrepaired can induce mutations and contribute to skin cancer. The two most common UV-induced DNA lesions are the cis-syn cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs), both of which can initiate mutations. Interestingly, mutation frequency across the genomes of many cancers is heterogenous with significant increases in heterochromatin. Corresponding increases in UV lesion susceptibility and decreases in repair are observed in heterochromatin versus euchromatin. However, the individual contributions of CPDs and 6-4PPs to mutagenesis have not been systematically examined in specific genomic and epigenomic contexts. In this study, we compared genome-wide maps of 6-4PP and CPD lesion abundances in primary cells and conducted comprehensive analyses to determine the genetic and epigenetic features associated with susceptibility. Overall, we found a high degree of similarity between 6-4PP and CPD formation, with an enrichment of both in heterochromatin regions. However, when examining the relative levels of the two UV lesions, we found that bivalent and Polycomb-repressed chromatin states were uniquely more susceptible to 6-4PPs. Interestingly, when comparing UV susceptibility and repair with melanoma mutation frequency in these regions, disparate patterns were observed in that susceptibility was not always inversely associated with repair and mutation frequency. Functional enrichment analysis hint at mechanisms of negative selection for these regions that are essential for cell viability, immune function and induce cell death when mutated. Ultimately, these results reveal both the similarities and differences between UV-induced lesions that contribute to melanoma.
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Affiliation(s)
- Brian S Perez
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Ka Man Wong
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Erin K Schwartz
- Department of Biology, Stanford University, Stanford, CA, USA
| | | | - Devin A King
- Department of Biology, Stanford University, Stanford, CA, USA
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46
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Erenpreisa J, Krigerts J, Salmina K, Gerashchenko BI, Freivalds T, Kurg R, Winter R, Krufczik M, Zayakin P, Hausmann M, Giuliani A. Heterochromatin Networks: Topology, Dynamics, and Function (a Working Hypothesis). Cells 2021; 10:1582. [PMID: 34201566 PMCID: PMC8304199 DOI: 10.3390/cells10071582] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/17/2021] [Accepted: 06/21/2021] [Indexed: 12/21/2022] Open
Abstract
Open systems can only exist by self-organization as pulsing structures exchanging matter and energy with the outer world. This review is an attempt to reveal the organizational principles of the heterochromatin supra-intra-chromosomal network in terms of nonlinear thermodynamics. The accessibility of the linear information of the genetic code is regulated by constitutive heterochromatin (CHR) creating the positional information in a system of coordinates. These features include scale-free splitting-fusing of CHR with the boundary constraints of the nucleolus and nuclear envelope. The analysis of both the literature and our own data suggests a radial-concentric network as the main structural organization principle of CHR regulating transcriptional pulsing. The dynamic CHR network is likely created together with nucleolus-associated chromatin domains, while the alveoli of this network, including springy splicing speckles, are the pulsing transcription hubs. CHR contributes to this regulation due to the silencing position variegation effect, stickiness, and flexible rigidity determined by the positioning of nucleosomes. The whole system acts in concert with the elastic nuclear actomyosin network which also emerges by self-organization during the transcriptional pulsing process. We hypothesize that the the transcriptional pulsing, in turn, adjusts its frequency/amplitudes specified by topologically associating domains to the replication timing code that determines epigenetic differentiation memory.
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Affiliation(s)
- Jekaterina Erenpreisa
- Latvian Biomedicine Research and Study Centre, LV-1067 Riga, Latvia; (J.K.); (K.S.); (P.Z.)
| | - Jekabs Krigerts
- Latvian Biomedicine Research and Study Centre, LV-1067 Riga, Latvia; (J.K.); (K.S.); (P.Z.)
| | - Kristine Salmina
- Latvian Biomedicine Research and Study Centre, LV-1067 Riga, Latvia; (J.K.); (K.S.); (P.Z.)
| | - Bogdan I. Gerashchenko
- R.E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology, National Academy of Sciences of Ukraine, 03022 Kyiv, Ukraine;
| | - Talivaldis Freivalds
- Institute of Cardiology and Regenerative Medicine, University of Latvia, LV-1004 Riga, Latvia;
| | - Reet Kurg
- Institute of Technology, University of Tartu, 50411 Tartu, Estonia;
| | - Ruth Winter
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany; (R.W.); (M.K.); (M.H.)
| | - Matthias Krufczik
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany; (R.W.); (M.K.); (M.H.)
| | - Pawel Zayakin
- Latvian Biomedicine Research and Study Centre, LV-1067 Riga, Latvia; (J.K.); (K.S.); (P.Z.)
| | - Michael Hausmann
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany; (R.W.); (M.K.); (M.H.)
| | - Alessandro Giuliani
- Istituto Superiore di Sanita Environment and Health Department, 00161 Roma, Italy
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47
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Lu JY, Chang L, Li T, Wang T, Yin Y, Zhan G, Han X, Zhang K, Tao Y, Percharde M, Wang L, Peng Q, Yan P, Zhang H, Bi X, Shao W, Hong Y, Wu Z, Ma R, Wang P, Li W, Zhang J, Chang Z, Hou Y, Zhu B, Ramalho-Santos M, Li P, Xie W, Na J, Sun Y, Shen X. Homotypic clustering of L1 and B1/Alu repeats compartmentalizes the 3D genome. Cell Res 2021; 31:613-630. [PMID: 33514913 PMCID: PMC8169921 DOI: 10.1038/s41422-020-00466-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 12/17/2020] [Indexed: 01/30/2023] Open
Abstract
Organization of the genome into euchromatin and heterochromatin appears to be evolutionarily conserved and relatively stable during lineage differentiation. In an effort to unravel the basic principle underlying genome folding, here we focus on the genome itself and report a fundamental role for L1 (LINE1 or LINE-1) and B1/Alu retrotransposons, the most abundant subclasses of repetitive sequences, in chromatin compartmentalization. We find that homotypic clustering of L1 and B1/Alu demarcates the genome into grossly exclusive domains, and characterizes and predicts Hi-C compartments. Spatial segregation of L1-rich sequences in the nuclear and nucleolar peripheries and B1/Alu-rich sequences in the nuclear interior is conserved in mouse and human cells and occurs dynamically during the cell cycle. In addition, de novo establishment of L1 and B1 nuclear segregation is coincident with the formation of higher-order chromatin structures during early embryogenesis and appears to be critically regulated by L1 and B1 transcripts. Importantly, depletion of L1 transcripts in embryonic stem cells drastically weakens homotypic repeat contacts and compartmental strength, and disrupts the nuclear segregation of L1- or B1-rich chromosomal sequences at genome-wide and individual sites. Mechanistically, nuclear co-localization and liquid droplet formation of L1 repeat DNA and RNA with heterochromatin protein HP1α suggest a phase-separation mechanism by which L1 promotes heterochromatin compartmentalization. Taken together, we propose a genetically encoded model in which L1 and B1/Alu repeats blueprint chromatin macrostructure. Our model explains the robustness of genome folding into a common conserved core, on which dynamic gene regulation is overlaid across cells.
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Affiliation(s)
- J. Yuyang Lu
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Lei Chang
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, and College of Future Technology, Peking University, Beijing, 100871 China ,grid.508040.9Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, Guangdong, 510005 China
| | - Tong Li
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Ting Wang
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Yafei Yin
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Ge Zhan
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Xue Han
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Ke Zhang
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Yibing Tao
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Michelle Percharde
- grid.14105.310000000122478951MRC London Institute of Medical Sciences (LMS), London, W120NN UK ,grid.7445.20000 0001 2113 8111Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, W120NN UK
| | - Liang Wang
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Qi Peng
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Pixi Yan
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Hui Zhang
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Xianju Bi
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Wen Shao
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Yantao Hong
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Zhongyang Wu
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Runze Ma
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
| | - Peizhe Wang
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Wenzhi Li
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Jing Zhang
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Zai Chang
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Yingping Hou
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, and College of Future Technology, Peking University, Beijing, 100871 China
| | - Bing Zhu
- grid.9227.e0000000119573309National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
| | - Miguel Ramalho-Santos
- grid.17063.330000 0001 2157 2938Lunenfeld-Tanenbaum Research Institute, University of Toronto, Toronto, Ontario M5T 3H7 Canada
| | - Pilong Li
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Wei Xie
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Jie Na
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Yujie Sun
- grid.11135.370000 0001 2256 9319State Key Laboratory of Membrane Biology, Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, and College of Future Technology, Peking University, Beijing, 100871 China
| | - Xiaohua Shen
- grid.12527.330000 0001 0662 3178Tsinghua-Peking Joint Center for Life Sciences, School of Medicine and School of Life Sciences, Tsinghua University, Beijing, 100084 China
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48
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Qiu GH, Zheng X, Fu M, Huang C, Yang X. The decreased exclusion of nuclear eccDNA: From molecular and subcellular levels to human aging and age-related diseases. Ageing Res Rev 2021; 67:101306. [PMID: 33610814 DOI: 10.1016/j.arr.2021.101306] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 12/11/2022]
Abstract
Extrachromosomal circular DNA (eccDNA) accumulates within the nucleus of eukaryotic cells during physiological aging and in age-related diseases (ARDs) and the accumulation could be caused by the declined exclusion of nuclear eccDNA in these states. This review focuses on the formation of eccDNA and the roles of some main factors, such as nuclear pore complexes (NPCs), nucleoplasmic reticulum (NR), and nuclear actin, in eccDNA exclusion. eccDNAs are mostly formed from non-coding DNA during DNA damage repair. They move to NPCs along nuclear actin and are excluded out of the nucleus through functional NPCs in young and healthy cells. However, it has been demonstrated that defective NPCs, abnormal NPC components and nuclear actin rods are increased in aged cells, various cancers and certain other ARDs such as cardiovascular diseases, premature aging, neurodegenerative diseases and myopathies. Therefore, mainly resulting from the increase of dysfunctional NPCs, the exclusion of nuclear eccDNAs may be reduced and eccDNAs thus accumulate within the nucleus in aging and the aforementioned ARDs. In addition, the protective function of non-coding DNA in tumorigenesis is further discussed.
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Affiliation(s)
- Guo-Hua Qiu
- Fujian Provincial Key Laboratory for the Prevention and Control of Animal Infectious Diseases and Biotechnology, Key Laboratory of Preventive Veterinary Medicine and Biotechnology, Fujian Province Universities, College of Life Sciences, Longyan University, Longyan 364012, People's Republic of China.
| | - Xintian Zheng
- Fujian Provincial Key Laboratory for the Prevention and Control of Animal Infectious Diseases and Biotechnology, Key Laboratory of Preventive Veterinary Medicine and Biotechnology, Fujian Province Universities, College of Life Sciences, Longyan University, Longyan 364012, People's Republic of China
| | - Mingjun Fu
- Fujian Provincial Key Laboratory for the Prevention and Control of Animal Infectious Diseases and Biotechnology, Key Laboratory of Preventive Veterinary Medicine and Biotechnology, Fujian Province Universities, College of Life Sciences, Longyan University, Longyan 364012, People's Republic of China
| | - Cuiqin Huang
- Fujian Provincial Key Laboratory for the Prevention and Control of Animal Infectious Diseases and Biotechnology, Key Laboratory of Preventive Veterinary Medicine and Biotechnology, Fujian Province Universities, College of Life Sciences, Longyan University, Longyan 364012, People's Republic of China
| | - Xiaoyan Yang
- Fujian Provincial Key Laboratory for the Prevention and Control of Animal Infectious Diseases and Biotechnology, Key Laboratory of Preventive Veterinary Medicine and Biotechnology, Fujian Province Universities, College of Life Sciences, Longyan University, Longyan 364012, People's Republic of China
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49
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dos Santos Á, Toseland CP. Regulation of Nuclear Mechanics and the Impact on DNA Damage. Int J Mol Sci 2021; 22:3178. [PMID: 33804722 PMCID: PMC8003950 DOI: 10.3390/ijms22063178] [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: 02/25/2021] [Revised: 03/15/2021] [Accepted: 03/18/2021] [Indexed: 02/06/2023] Open
Abstract
In eukaryotic cells, the nucleus houses the genomic material of the cell. The physical properties of the nucleus and its ability to sense external mechanical cues are tightly linked to the regulation of cellular events, such as gene expression. Nuclear mechanics and morphology are altered in many diseases such as cancer and premature ageing syndromes. Therefore, it is important to understand how different components contribute to nuclear processes, organisation and mechanics, and how they are misregulated in disease. Although, over the years, studies have focused on the nuclear lamina-a mesh of intermediate filament proteins residing between the chromatin and the nuclear membrane-there is growing evidence that chromatin structure and factors that regulate chromatin organisation are essential contributors to the physical properties of the nucleus. Here, we review the main structural components that contribute to the mechanical properties of the nucleus, with particular emphasis on chromatin structure. We also provide an example of how nuclear stiffness can both impact and be affected by cellular processes such as DNA damage and repair.
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Affiliation(s)
- Ália dos Santos
- Department of Oncology and Metabolism, University of Sheffield, Sheffield S10 2RX, UK
| | - Christopher P. Toseland
- Department of Oncology and Metabolism, University of Sheffield, Sheffield S10 2RX, UK
- Insigneo Institute for in Silico Medicine, University of Sheffield, Sheffield S10 2RX, UK
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50
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Krigerts J, Salmina K, Freivalds T, Zayakin P, Rumnieks F, Inashkina I, Giuliani A, Hausmann M, Erenpreisa J. Differentiating cancer cells reveal early large-scale genome regulation by pericentric domains. Biophys J 2021; 120:711-724. [PMID: 33453273 PMCID: PMC7896032 DOI: 10.1016/j.bpj.2021.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/30/2020] [Accepted: 01/07/2021] [Indexed: 02/07/2023] Open
Abstract
Finding out how cells prepare for fate change during differentiation commitment was our task. To address whether the constitutive pericentromere-associated domains (PADs) may be involved, we used a model system with known transcriptome data, MCF-7 breast cancer cells treated with the ErbB3 ligand heregulin (HRG), which induces differentiation and is used in the therapy of cancer. PAD-repressive heterochromatin (H3K9me3), centromere-associated-protein-specific, and active euchromatin (H3K4me3) antibodies, real-time PCR, acridine orange DNA structural test (AOT), and microscopic image analysis were applied. We found a two-step DNA unfolding after 15–20 and 60 min of HRG treatment, respectively. This behavior was consistent with biphasic activation of the early response genes (c-fos - fosL1/myc) and the timing of two transcriptome avalanches reported in the literature. In control, the average number of PADs negatively correlated with their size by scale-free distribution, and centromere clustering in turn correlated with PAD size, both indicating that PADs may create and modulate a suprachromosomal network by fusing and splitting a constant proportion of the constitutive heterochromatin. By 15 min of HRG treatment, the bursting unraveling of PADs from the nucleolus boundary occurred, coinciding with the first step of H3K4me3 chromatin unfolding, confirmed by AOT. The second step after 60 min of HRG treatment was associated with transcription of long noncoding RNA from PADs and peaking of fosL1/c-myc response. We hypothesize that the bursting of PAD clusters under a critical silencing threshold pushes the first transcription avalanche, whereas the destruction of the PAD network enables genome rewiring needed for differentiation repatterning, mediated by early response bivalent genes.
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Affiliation(s)
- Jekabs Krigerts
- Latvian Biomedicine Research and Study Centre, Riga, Latvia; University of Latvia, Riga, Latvia
| | | | - Talivaldis Freivalds
- Institute of Cardiology and Regenerative Medicine, University of Latvia, Riga, Latvia
| | - Pawel Zayakin
- Latvian Biomedicine Research and Study Centre, Riga, Latvia
| | - Felikss Rumnieks
- Latvian Biomedicine Research and Study Centre, Riga, Latvia; University of Latvia, Riga, Latvia
| | - Inna Inashkina
- Latvian Biomedicine Research and Study Centre, Riga, Latvia
| | - Alessandro Giuliani
- Environment and Health Department, Italian National Institute of Health, Rome, Italy
| | - Michael Hausmann
- Kirchhoff Institute for Physics, Heidelberg University, Heidelberg, Germany.
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