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Lin YY, Müller P, Karagianni E, Hepp N, Mueller-Planitz F, Vanderlinden W, Lipfert J. Epigenetic Histone Modifications H3K36me3 and H4K5/8/12/16ac Induce Open Polynucleosome Conformations via Different Mechanisms. J Mol Biol 2024; 436:168671. [PMID: 38908785 DOI: 10.1016/j.jmb.2024.168671] [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: 02/18/2024] [Revised: 05/28/2024] [Accepted: 06/16/2024] [Indexed: 06/24/2024]
Abstract
Nucleosomes are the basic compaction unit of chromatin and nucleosome structure and their higher-order assemblies regulate genome accessibility. Many post-translational modifications alter nucleosome dynamics, nucleosome-nucleosome interactions, and ultimately chromatin structure and gene expression. Here, we investigate the role of two post-translational modifications associated with actively transcribed regions, H3K36me3 and H4K5/8/12/16ac, in the contexts of tri-nucleosome arrays that provide a tractable model system for quantitative single-molecule analysis, while enabling us to probe nucleosome-nucleosome interactions. Direct visualization by AFM imaging reveals that H3K36me3 and H4K5/8/12/16ac nucleosomes adopt significantly more open and loose conformations than unmodified nucleosomes. Similarly, magnetic tweezers force spectroscopy shows a reduction in DNA outer turn wrapping and nucleosome-nucleosome interactions for the modified nucleosomes. The results suggest that for H3K36me3 the increased breathing and outer DNA turn unwrapping seen in mononucleosomes propagates to more open conformations in nucleosome arrays. In contrast, the even more open structures of H4K5/8/12/16ac nucleosome arrays do not appear to derive from the dynamics of the constituent mononucleosomes, but are driven by reduced nucleosome-nucleosome interactions, suggesting that stacking interactions can overrule DNA breathing of individual nucleosomes. We anticipate that our methodology will be broadly applicable to reveal the influence of other post-translational modifications and to observe the activity of nucleosome remodelers.
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Affiliation(s)
- Yi-Yun Lin
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Amaliensstrasse 54, 80799 Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, the Netherlands
| | - Peter Müller
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Amaliensstrasse 54, 80799 Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, the Netherlands
| | - Evdoxia Karagianni
- Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, the Netherlands
| | - Nicola Hepp
- Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany; Current address: Department of Clinical Genetics, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Felix Mueller-Planitz
- Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Willem Vanderlinden
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Amaliensstrasse 54, 80799 Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, the Netherlands; School of Physics and Astronomy, University of Edinburg, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom.
| | - Jan Lipfert
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Amaliensstrasse 54, 80799 Munich, Germany; Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, the Netherlands.
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Brancato D, Bruno F, Coniglio E, Sturiale V, Saccone S, Federico C. The Chromatin Organization Close to SNP rs12913832, Involved in Eye Color Variation, Is Evolutionary Conserved in Vertebrates. Int J Mol Sci 2024; 25:6602. [PMID: 38928306 PMCID: PMC11204186 DOI: 10.3390/ijms25126602] [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: 05/19/2024] [Revised: 06/12/2024] [Accepted: 06/12/2024] [Indexed: 06/28/2024] Open
Abstract
The most significant genetic influence on eye color pigmentation is attributed to the intronic SNP rs12913832 in the HERC2 gene, which interacts with the promoter region of the contiguous OCA2 gene. This interaction, through the formation of a chromatin loop, modulates the transcriptional activity of OCA2, directly affecting eye color pigmentation. Recent advancements in technology have elucidated the precise spatial organization of the genome within the cell nucleus, with chromatin architecture playing a pivotal role in regulating various genome functions. In this study, we investigated the organization of the chromatin close to the HERC2/OCA2 locus in human lymphocyte nuclei using fluorescence in situ hybridization (FISH) and high-throughput chromosome conformation capture (Hi-C) data. The 3 Mb of genomic DNA that belonged to the chromosomal region 15q12-q13.1 revealed the presence of three contiguous chromatin loops, which exhibited a different level of compaction depending on the presence of the A or G allele in the SNP rs12913832. Moreover, the analysis of the genomic organization of the genes has demonstrated that this chromosomal region is evolutionarily highly conserved, as evidenced by the analysis of syntenic regions in species from other Vertebrate classes. Thus, the role of rs12913832 variant is relevant not only in determining the transcriptional activation of the OCA2 gene but also in the chromatin compaction of a larger region, underscoring the critical role of chromatin organization in the proper regulation of the involved genes. It is crucial to consider the broader implications of this finding, especially regarding the potential regulatory role of similar polymorphisms located within intronic regions, which do not influence the same gene by modulating the splicing process, but they regulate the expression of adjacent genes. Therefore, caution should be exercised when utilizing whole-exome sequencing for diagnostic purposes, as intron sequences may provide valuable gene regulation information on the region where they reside. Thus, future research efforts should also be directed towards gaining a deeper understanding of the precise mechanisms underlying the role and mode of action of intronic SNPs in chromatin loop organization and transcriptional regulation.
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Affiliation(s)
| | | | | | | | - Salvatore Saccone
- Department Biological, Geological and Environmental Sciences, University of Catania, Via Androne 81, 95124 Catania, Italy; (D.B.); (F.B.); (E.C.); (V.S.); (C.F.)
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He J, Huo X, Pei G, Jia Z, Yan Y, Yu J, Qu H, Xie Y, Yuan J, Zheng Y, Hu Y, Shi M, You K, Li T, Ma T, Zhang MQ, Ding S, Li P, Li Y. Dual-role transcription factors stabilize intermediate expression levels. Cell 2024; 187:2746-2766.e25. [PMID: 38631355 DOI: 10.1016/j.cell.2024.03.023] [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: 06/09/2023] [Revised: 12/08/2023] [Accepted: 03/18/2024] [Indexed: 04/19/2024]
Abstract
Precise control of gene expression levels is essential for normal cell functions, yet how they are defined and tightly maintained, particularly at intermediate levels, remains elusive. Here, using a series of newly developed sequencing, imaging, and functional assays, we uncover a class of transcription factors with dual roles as activators and repressors, referred to as condensate-forming level-regulating dual-action transcription factors (TFs). They reduce high expression but increase low expression to achieve stable intermediate levels. Dual-action TFs directly exert activating and repressing functions via condensate-forming domains that compartmentalize core transcriptional unit selectively. Clinically relevant mutations in these domains, which are linked to a range of developmental disorders, impair condensate selectivity and dual-action TF activity. These results collectively address a fundamental question in expression regulation and demonstrate the potential of level-regulating dual-action TFs as powerful effectors for engineering controlled expression levels.
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Affiliation(s)
- Jinnan He
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Xiangru Huo
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Gaofeng Pei
- State Key Laboratory of Membrane Biology, Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua University-Peking University Joint Center for Life Sciences, Beijing 100084, China
| | - Zeran Jia
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Yiming Yan
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Jiawei Yu
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Haozhi Qu
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Yunxin Xie
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Junsong Yuan
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Yuan Zheng
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Yanyan Hu
- School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China; Tsinghua University-Peking University Joint Center for Life Sciences, Beijing 100084, China
| | - Minglei Shi
- Bioinformatics Division, National Research Center for Information Science and Technology, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Kaiqiang You
- Department of Biomedical Informatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Tingting Li
- Department of Biomedical Informatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Tianhua Ma
- School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China; Tsinghua University-Peking University Joint Center for Life Sciences, Beijing 100084, China
| | - Michael Q Zhang
- Bioinformatics Division, National Research Center for Information Science and Technology, School of Medicine, Tsinghua University, Beijing 100084, China; Department of Biological Sciences, Center for Systems Biology, The University of Texas, Dallas, TX 75080-3021, USA
| | - Sheng Ding
- School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China; Tsinghua University-Peking University Joint Center for Life Sciences, Beijing 100084, China
| | - Pilong Li
- State Key Laboratory of Membrane Biology, Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua University-Peking University Joint Center for Life Sciences, Beijing 100084, China.
| | - Yinqing Li
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China.
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4
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Boob AG, Zhu Z, Intasian P, Jain M, Petrov V, Lane ST, Tan SI, Xun G, Zhao H. CRISPR-COPIES: an in silico platform for discovery of neutral integration sites for CRISPR/Cas-facilitated gene integration. Nucleic Acids Res 2024; 52:e30. [PMID: 38346683 PMCID: PMC11014336 DOI: 10.1093/nar/gkae062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 01/09/2024] [Accepted: 01/19/2024] [Indexed: 04/14/2024] Open
Abstract
The CRISPR/Cas system has emerged as a powerful tool for genome editing in metabolic engineering and human gene therapy. However, locating the optimal site on the chromosome to integrate heterologous genes using the CRISPR/Cas system remains an open question. Selecting a suitable site for gene integration involves considering multiple complex criteria, including factors related to CRISPR/Cas-mediated integration, genetic stability, and gene expression. Consequently, identifying such sites on specific or different chromosomal locations typically requires extensive characterization efforts. To address these challenges, we have developed CRISPR-COPIES, a COmputational Pipeline for the Identification of CRISPR/Cas-facilitated intEgration Sites. This tool leverages ScaNN, a state-of-the-art model on the embedding-based nearest neighbor search for fast and accurate off-target search, and can identify genome-wide intergenic sites for most bacterial and fungal genomes within minutes. As a proof of concept, we utilized CRISPR-COPIES to characterize neutral integration sites in three diverse species: Saccharomyces cerevisiae, Cupriavidus necator, and HEK293T cells. In addition, we developed a user-friendly web interface for CRISPR-COPIES (https://biofoundry.web.illinois.edu/copies/). We anticipate that CRISPR-COPIES will serve as a valuable tool for targeted DNA integration and aid in the characterization of synthetic biology toolkits, enable rapid strain construction to produce valuable biochemicals, and support human gene and cell therapy applications.
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Affiliation(s)
- Aashutosh Girish Boob
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Zhixin Zhu
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Pattarawan Intasian
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan Valley, Rayong 21210, Thailand
| | - Manan Jain
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Vassily Andrew Petrov
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Stephan Thomas Lane
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shih-I Tan
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Guanhua Xun
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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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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Park S, Athreya A, Carrizo GE, Benning NA, Mitchener MM, Bhanu NV, Garcia BA, Zhang B, Muir TW, Pearce EL, Ha T. Electrostatic encoding of genome organization principles within single native nucleosomes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.08.570828. [PMID: 38106048 PMCID: PMC10723453 DOI: 10.1101/2023.12.08.570828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The eukaryotic genome, first packed into nucleosomes of about 150 bp around the histone core, is organized into euchromatin and heterochromatin, corresponding to the A and B compartments, respectively. Here, we asked if individual nucleosomes in vivo know where to go. That is, do mono-nucleosomes by themselves contain A/B compartment information, associated with transcription activity, in their biophysical properties? We purified native mono-nucleosomes to high monodispersity and used physiological concentrations of biological polyamines to determine their condensability. The chromosomal regions known to partition into A compartments have low condensability and vice versa. In silico chromatin polymer simulations using condensability as the only input showed that biophysical information needed to form compartments is all contained in single native nucleosomes and no other factors are needed. Condensability is also strongly anticorrelated with gene expression, and especially so near the promoter region and in a cell type dependent manner. Therefore, individual nucleosomes in the promoter know whether the gene is on or off, and that information is contained in their biophysical properties. Comparison with genetic and epigenetic features suggest that nucleosome condensability is a very meaningful axis onto which to project the high dimensional cellular chromatin state. Analysis of condensability using various condensing agents including those that are protein-based suggests that genome organization principle encoded into individual nucleosomes is electrostatic in nature. Polyamine depletion in mouse T cells, by either knocking out ornithine decarboxylase (ODC) or inhibiting ODC, results in hyperpolarized condensability, suggesting that when cells cannot rely on polyamines to translate biophysical properties of nucleosomes to control gene expression and 3D genome organization, they accentuate condensability contrast, which may explain dysfunction known to occur with polyamine deficiency.
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Affiliation(s)
- Sangwoo Park
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Advait Athreya
- Computational and Systems Biology Program, MIT, Cambridge, MA, 02139, USA
| | - Gustavo Ezequiel Carrizo
- Department of Oncology, The Bloomberg–Kimmel Institute for Cancer Immunotherapy, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Nils A. Benning
- Department of Biology, Johns Hopkins University. Baltimore, MD 21218, USA
| | | | - Natarajan V. Bhanu
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine St. Louis, St. Louis, MO 63110, USA
| | - Benjamin A. Garcia
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine St. Louis, St. Louis, MO 63110, USA
| | - Bin Zhang
- Department of Chemistry, MIT, Cambridge, MA 02139, USA
| | - Tom W. Muir
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Erika L. Pearce
- Department of Oncology, The Bloomberg–Kimmel Institute for Cancer Immunotherapy, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Biochemistry and Molecular Biology Department, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
- Howard Hughes Medical Institute, Boston, MA 02115, USA
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Shivashankar GV. Mechanical forces and the 3D genome. Curr Opin Struct Biol 2023; 83:102728. [PMID: 37948897 DOI: 10.1016/j.sbi.2023.102728] [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: 07/10/2023] [Revised: 10/09/2023] [Accepted: 10/16/2023] [Indexed: 11/12/2023]
Abstract
Traditionally, the field of genomics has been studied from a biochemical perspective. Besides chemical influences, cells are subject to a variety of mechanical signals from their surrounding tissue microenvironment. These mechanical signals can not only cause changes to a cell's physical structure but can also lead to alterations in their genomes and gene expression programs. Understanding the mechanical control of genome organization and expression may provide a new perspective on gene regulation.
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Lee GE, Byun J, Lee CJ, Cho YY. Molecular Mechanisms for the Regulation of Nuclear Membrane Integrity. Int J Mol Sci 2023; 24:15497. [PMID: 37895175 PMCID: PMC10607757 DOI: 10.3390/ijms242015497] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/19/2023] [Accepted: 10/22/2023] [Indexed: 10/29/2023] Open
Abstract
The nuclear membrane serves a critical role in protecting the contents of the nucleus and facilitating material and signal exchange between the nucleus and cytoplasm. While extensive research has been dedicated to topics such as nuclear membrane assembly and disassembly during cell division, as well as interactions between nuclear transmembrane proteins and both nucleoskeletal and cytoskeletal components, there has been comparatively less emphasis on exploring the regulation of nuclear morphology through nuclear membrane integrity. In particular, the role of type II integral proteins, which also function as transcription factors, within the nuclear membrane remains an area of research that is yet to be fully explored. The integrity of the nuclear membrane is pivotal not only during cell division but also in the regulation of gene expression and the communication between the nucleus and cytoplasm. Importantly, it plays a significant role in the development of various diseases. This review paper seeks to illuminate the biomolecules responsible for maintaining the integrity of the nuclear membrane. It will delve into the mechanisms that influence nuclear membrane integrity and provide insights into the role of type II membrane protein transcription factors in this context. Understanding these aspects is of utmost importance, as it can offer valuable insights into the intricate processes governing nuclear membrane integrity. Such insights have broad-reaching implications for cellular function and our understanding of disease pathogenesis.
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Affiliation(s)
- Ga-Eun Lee
- BK21-4th, and BRL, College of Pharmacy, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si 14662, Gyeonggi-do, Republic of Korea; (G.-E.L.); (J.B.)
| | - Jiin Byun
- BK21-4th, and BRL, College of Pharmacy, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si 14662, Gyeonggi-do, Republic of Korea; (G.-E.L.); (J.B.)
| | - Cheol-Jung Lee
- Research Center for Materials Analysis, Korea Basic Science Institute, 169-148, Gwahak-ro, Yuseong-gu, Daejeon 34133, Chungcheongnam-do, Republic of Korea
| | - Yong-Yeon Cho
- BK21-4th, and BRL, College of Pharmacy, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si 14662, Gyeonggi-do, Republic of Korea; (G.-E.L.); (J.B.)
- RCD Control and Material Research Institute, The Catholic University of Korea, 43, Jibong-ro, Wonmi-gu, Bucheon-si 14662, Gyeonggi-do, Republic of Korea
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Forte G, Buckle A, Boyle S, Marenduzzo D, Gilbert N, Brackley CA. Transcription modulates chromatin dynamics and locus configuration sampling. Nat Struct Mol Biol 2023; 30:1275-1285. [PMID: 37537334 PMCID: PMC10497412 DOI: 10.1038/s41594-023-01059-8] [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: 11/12/2021] [Accepted: 07/07/2023] [Indexed: 08/05/2023]
Abstract
In living cells, the 3D structure of gene loci is dynamic, but this is not revealed by 3C and FISH experiments in fixed samples, leaving a notable gap in our understanding. To overcome these limitations, we applied the highly predictive heteromorphic polymer (HiP-HoP) model to determine chromatin fiber mobility at the Pax6 locus in three mouse cell lines with different transcription states. While transcriptional activity minimally affects movement of 40-kbp regions, we observed that motion of smaller 1-kbp regions depends strongly on local disruption to chromatin fiber structure marked by H3K27 acetylation. This also substantially influenced locus configuration dynamics by modulating protein-mediated promoter-enhancer loops. Importantly, these simulations indicate that chromatin dynamics are sufficiently fast to sample all possible locus conformations within minutes, generating wide dynamic variability within single cells. This combination of simulation and experimental validation provides insight into how transcriptional activity influences chromatin structure and gene dynamics.
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Affiliation(s)
- Giada Forte
- SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
| | - Adam Buckle
- MRC Human Genetics Unit, Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Shelagh Boyle
- MRC Human Genetics Unit, Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Davide Marenduzzo
- SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
| | - Nick Gilbert
- MRC Human Genetics Unit, Institute of Genetics & Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK.
| | - Chris A Brackley
- SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK.
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Simpson DJ, Zhao Q, Olova NN, Dabrowski J, Xie X, Latorre‐Crespo E, Chandra T. Region-based epigenetic clock design improves RRBS-based age prediction. Aging Cell 2023; 22:e13866. [PMID: 37170475 PMCID: PMC10410054 DOI: 10.1111/acel.13866] [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: 02/08/2023] [Revised: 04/20/2023] [Accepted: 04/21/2023] [Indexed: 05/13/2023] Open
Abstract
Recent studies suggest that epigenetic rejuvenation can be achieved using drugs that mimic calorie restriction and techniques such as reprogramming-induced rejuvenation. To effectively test rejuvenation in vivo, mouse models are the safest alternative. However, we have found that the recent epigenetic clocks developed for mouse reduced-representation bisulphite sequencing (RRBS) data have significantly poor performance when applied to external datasets. We show that the sites captured and the coverage of key CpGs required for age prediction vary greatly between datasets, which likely contributes to the lack of transferability in RRBS clocks. To mitigate these coverage issues in RRBS-based age prediction, we present two novel design strategies that use average methylation over large regions rather than individual CpGs, whereby regions are defined by sliding windows (e.g. 5 kb), or density-based clustering of CpGs. We observe improved correlation and error in our regional blood clocks (RegBCs) compared to published individual-CpG-based techniques when applied to external datasets. The RegBCs are also more robust when applied to low coverage data and detect a negative age acceleration in mice undergoing calorie restriction. Our RegBCs offer a proof of principle that age prediction of RRBS datasets can be improved by accounting for multiple CpGs over a region, which negates the lack of read depth currently hindering individual-CpG-based approaches.
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Affiliation(s)
- Daniel J. Simpson
- MRC Human Genetics Unit, MRC Institute of Genetics and CancerUniversity of EdinburghEdinburghUK
| | - Qian Zhao
- MRC Human Genetics Unit, MRC Institute of Genetics and CancerUniversity of EdinburghEdinburghUK
| | - Nelly N. Olova
- MRC Human Genetics Unit, MRC Institute of Genetics and CancerUniversity of EdinburghEdinburghUK
| | - Jan Dabrowski
- MRC Human Genetics Unit, MRC Institute of Genetics and CancerUniversity of EdinburghEdinburghUK
| | - Xiaoxiao Xie
- MRC Human Genetics Unit, MRC Institute of Genetics and CancerUniversity of EdinburghEdinburghUK
| | - Eric Latorre‐Crespo
- MRC Human Genetics Unit, MRC Institute of Genetics and CancerUniversity of EdinburghEdinburghUK
| | - Tamir Chandra
- MRC Human Genetics Unit, MRC Institute of Genetics and CancerUniversity of EdinburghEdinburghUK
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11
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Yin Z, Cui S, Xue S, Xie Y, Wang Y, Zhao C, Zhang Z, Wu T, Hou G, Wang W, Xie SQ, Wu Y, Guo Y. Identification of Two Subsets of Subcompartment A1 Associated with High Transcriptional Activity and Frequent Loop Extrusion. BIOLOGY 2023; 12:1058. [PMID: 37626945 PMCID: PMC10451812 DOI: 10.3390/biology12081058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 07/24/2023] [Accepted: 07/24/2023] [Indexed: 08/27/2023]
Abstract
Three-dimensional genome organization has been increasingly recognized as an important determinant of the precise regulation of gene expression in mammalian cells, yet the relationship between gene transcriptional activity and spatial subcompartment positioning is still not fully comprehended. Here, we first utilized genome-wide Hi-C data to infer eight types of subcompartment (labeled A1, A2, A3, A4, B1, B2, B3, and B4) in mouse embryonic stem cells and four primary differentiated cell types, including thymocytes, macrophages, neural progenitor cells, and cortical neurons. Transitions of subcompartments may confer gene expression changes in different cell types. Intriguingly, we identified two subsets of subcompartments defined by higher gene density and characterized by strongly looped contact domains, named common A1 and variable A1, respectively. We revealed that common A1, which includes highly expressed genes and abundant housekeeping genes, shows a ~2-fold higher gene density than the variable A1, where cell type-specific genes are significantly enriched. Thus, our study supports a model in which both types of genomic loci with constitutive and regulatory high transcriptional activity can drive the subcompartment A1 formation. Special chromatin subcompartment arrangement and intradomain interactions may, in turn, contribute to maintaining proper levels of gene expression, especially for regulatory non-housekeeping genes.
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Affiliation(s)
- Zihang Yin
- Sheng Yushou Center of Cell Biology and Immunology, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; (Z.Y.); (S.C.); (Y.X.); (Y.W.); (C.Z.); (Z.Z.); (T.W.)
- WLA Laboratories, Shanghai 201203, China
| | - Shuang Cui
- Sheng Yushou Center of Cell Biology and Immunology, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; (Z.Y.); (S.C.); (Y.X.); (Y.W.); (C.Z.); (Z.Z.); (T.W.)
- WLA Laboratories, Shanghai 201203, China
| | - Song Xue
- Department of Bioinformatics and Biostatistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China;
| | - Yufan Xie
- Sheng Yushou Center of Cell Biology and Immunology, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; (Z.Y.); (S.C.); (Y.X.); (Y.W.); (C.Z.); (Z.Z.); (T.W.)
- WLA Laboratories, Shanghai 201203, China
| | - Yefan Wang
- Sheng Yushou Center of Cell Biology and Immunology, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; (Z.Y.); (S.C.); (Y.X.); (Y.W.); (C.Z.); (Z.Z.); (T.W.)
- WLA Laboratories, Shanghai 201203, China
| | - Chengling Zhao
- Sheng Yushou Center of Cell Biology and Immunology, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; (Z.Y.); (S.C.); (Y.X.); (Y.W.); (C.Z.); (Z.Z.); (T.W.)
- WLA Laboratories, Shanghai 201203, China
| | - Zhiyu Zhang
- Sheng Yushou Center of Cell Biology and Immunology, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; (Z.Y.); (S.C.); (Y.X.); (Y.W.); (C.Z.); (Z.Z.); (T.W.)
- WLA Laboratories, Shanghai 201203, China
| | - Tao Wu
- Sheng Yushou Center of Cell Biology and Immunology, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; (Z.Y.); (S.C.); (Y.X.); (Y.W.); (C.Z.); (Z.Z.); (T.W.)
- WLA Laboratories, Shanghai 201203, China
| | - Guojun Hou
- Shanghai Institute of Rheumatology, Renji Hospital, Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai 200001, China;
| | - Wuming Wang
- CUHK-SDU Joint Laboratory on Reproductive Genetics, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China;
| | - Sheila Q. Xie
- MRC London Institute of Medical Sciences, London W12 0NN, UK;
- Institute of Clinical Sciences, Imperial College London, London W12 0NN, UK
| | - Yue Wu
- Department of Bioinformatics and Biostatistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China;
| | - Ya Guo
- Sheng Yushou Center of Cell Biology and Immunology, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; (Z.Y.); (S.C.); (Y.X.); (Y.W.); (C.Z.); (Z.Z.); (T.W.)
- WLA Laboratories, Shanghai 201203, China
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12
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Fatma Z, Tan SI, Boob AG, Zhao H. A landing pad system for multicopy gene integration in Issatchenkia orientalis. Metab Eng 2023; 78:200-208. [PMID: 37343658 DOI: 10.1016/j.ymben.2023.06.010] [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: 05/04/2023] [Revised: 06/18/2023] [Accepted: 06/18/2023] [Indexed: 06/23/2023]
Abstract
The robust nature of the non-conventional yeast Issatchenkia orientalis allows it to grow under highly acidic conditions and therefore, has gained increasing interest in producing organic acids using a variety of carbon sources. Recently, the development of a genetic toolbox for I. orientalis, including an episomal plasmid, characterization of multiple promoters and terminators, and CRISPR-Cas9 tools, has eased the metabolic engineering efforts in I. orientalis. However, multiplex engineering is still hampered by the lack of efficient multicopy integration tools. To facilitate the construction of large, complex metabolic pathways by multiplex CRISPR-Cas9-mediated genome editing, we developed a bioinformatics pipeline to identify and prioritize genome-wide intergenic loci and characterized 47 gRNAs located in 21 intergenic regions. These loci are screened for guide RNA cutting efficiency, integration efficiency of a gene cassette, the resulting cellular fitness, and GFP expression level. We further developed a landing pad system using components from these well-characterized loci, which can aid in the integration of multiple genes using single guide RNA and multiple repair templates of the user's choice. We have demonstrated the use of the landing pad for simultaneous integrations of 2, 3, 4, or 5 genes to the target loci with efficiencies greater than 80%. As a proof of concept, we showed how the production of 5-aminolevulinic acid can be improved by integrating five copies of genes at multiple sites in one step. We have further demonstrated the efficiency of this tool by constructing a metabolic pathway for succinic acid production by integrating five gene expression cassettes using a single guide RNA along with five different repair templates, leading to the production of 9 g/L of succinic acid in batch fermentations. This study demonstrates the effectiveness of a single gRNA-mediated CRISPR platform to build complex metabolic pathways in a non-conventional yeast. This landing pad system will be a valuable tool for the metabolic engineering of I. orientalis.
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Affiliation(s)
- Zia Fatma
- Department of Chemical and Biomolecular Engineering, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States
| | - Shih-I Tan
- Department of Chemical and Biomolecular Engineering, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States
| | - Aashutosh Girish Boob
- Department of Chemical and Biomolecular Engineering, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States; Departments of Chemistry, Biochemistry, and Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, United States.
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13
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Hara Y, Kuraku S. The impact of local genomic properties on the evolutionary fate of genes. eLife 2023; 12:82290. [PMID: 37223962 DOI: 10.7554/elife.82290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 04/25/2023] [Indexed: 05/25/2023] Open
Abstract
Functionally indispensable genes are likely to be retained and otherwise to be lost during evolution. This evolutionary fate of a gene can also be affected by factors independent of gene dispensability, including the mutability of genomic positions, but such features have not been examined well. To uncover the genomic features associated with gene loss, we investigated the characteristics of genomic regions where genes have been independently lost in multiple lineages. With a comprehensive scan of gene phylogenies of vertebrates with a careful inspection of evolutionary gene losses, we identified 813 human genes whose orthologs were lost in multiple mammalian lineages: designated 'elusive genes.' These elusive genes were located in genomic regions with rapid nucleotide substitution, high GC content, and high gene density. A comparison of the orthologous regions of such elusive genes across vertebrates revealed that these features had been established before the radiation of the extant vertebrates approximately 500 million years ago. The association of human elusive genes with transcriptomic and epigenomic characteristics illuminated that the genomic regions containing such genes were subject to repressive transcriptional regulation. Thus, the heterogeneous genomic features driving gene fates toward loss have been in place and may sometimes have relaxed the functional indispensability of such genes. This study sheds light on the complex interplay between gene function and local genomic properties in shaping gene evolution that has persisted since the vertebrate ancestor.
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Affiliation(s)
- Yuichiro Hara
- Research Center for Genome & Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Shigehiro Kuraku
- Molecular Life History Laboratory, Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Japan
- Department of Genetics, Sokendai (Graduate University for Advanced Studies), Mishima, Japan
- RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
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14
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Nifker G, Grunwald A, Margalit S, Tulpova Z, Michaeli Y, Har-Gil H, Maimon N, Roichman E, Schütz L, Weinhold E, Ebenstein Y. Dam Assisted Fluorescent Tagging of Chromatin Accessibility (DAFCA) for Optical Genome Mapping in Nanochannel Arrays. ACS NANO 2023; 17:9178-9187. [PMID: 37154345 DOI: 10.1021/acsnano.2c12755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Proteins and enzymes in the cell nucleus require physical access to their DNA target sites in order to perform genomic tasks such as gene activation and transcription. Hence, chromatin accessibility is a central regulator of gene expression, and its genomic profile holds essential information on the cell type and state. We utilized the E. coli Dam methyltransferase in combination with a fluorescent cofactor analogue to generate fluorescent tags in accessible DNA regions within the cell nucleus. The accessible portions of the genome are then detected by single-molecule optical genome mapping in nanochannel arrays. This method allowed us to characterize long-range structural variations and their associated chromatin structure. We show the ability to create whole-genome, allele-specific chromatin accessibility maps composed of long DNA molecules extended in silicon nanochannels.
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Affiliation(s)
- Gil Nifker
- Department of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 6997801 Tel Aviv, Israel
| | - Assaf Grunwald
- Department of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 6997801 Tel Aviv, Israel
| | - Sapir Margalit
- Department of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 6997801 Tel Aviv, Israel
| | - Zuzana Tulpova
- Department of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 6997801 Tel Aviv, Israel
| | - Yael Michaeli
- Department of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 6997801 Tel Aviv, Israel
| | - Hagai Har-Gil
- Department of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 6997801 Tel Aviv, Israel
| | - Noy Maimon
- Department of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 6997801 Tel Aviv, Israel
| | - Elad Roichman
- Department of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 6997801 Tel Aviv, Israel
| | - Leonie Schütz
- Institute of Organic Chemistry, RWTH Aachen University, D-52056 Aachen, Germany
| | - Elmar Weinhold
- Institute of Organic Chemistry, RWTH Aachen University, D-52056 Aachen, Germany
| | - Yuval Ebenstein
- Department of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 6997801 Tel Aviv, Israel
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, 6997801 Tel Aviv, Israel
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15
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Mandahl N, Mitelman F. Giemsa-negative chromosome bands preferentially recombine in cancer-associated translocations and gene fusions. Genes Chromosomes Cancer 2023; 62:61-74. [PMID: 36116030 PMCID: PMC10092824 DOI: 10.1002/gcc.23095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/08/2022] [Accepted: 09/11/2022] [Indexed: 12/13/2022] Open
Abstract
Chromosome abnormalities, in particular translocations, and gene fusions are hallmarks of neoplasia. Although both have been recognized as important drivers of cancer for decades, our knowledge of the characterizing features of the cytobands involved in recombinations is poorly understood. The present study, based on a comparative analysis of 10 442 translocation breakpoints and 30 762 gene fusions comprising 13 864 protein-coding genes, is the most comprehensive evaluation of the interactions of cytobands participating in the formation of such rearrangements in cancer. The major conclusion is that although large G-negative, gene-rich bands are most frequently involved, the greatest impact was seen for staining properties. Thus, 60% of the recombinations leading to the formation of both translocations and fusion genes take place between two G-negative bands whereas only about 10% involve two G-positive bands. There is compelling evidence that G-negative bands contain more genes than dark staining bands and it has previously been shown that breakpoints involved in structural chromosome rearrangements and in gene fusions preferentially affect gene-rich bands. The present study not only corroborates these findings but in addition demonstrates that the recombination processes favor the joining of two G-negative cytobands and that this feature may be a stronger factor than gene content. It is reasonable to assume that the formation of translocations and fusion genes in cancer cells, irrespective of whether they have a pathogenetically significant impact or not, may be mediated by some underlying mechanisms that either favor the origin or provide a selective advantage for recombinations of G-negative cytobands.
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Affiliation(s)
- Nils Mandahl
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Felix Mitelman
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, Lund, Sweden
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16
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Naughton C, Huidobro C, Catacchio CR, Buckle A, Grimes GR, Nozawa RS, Purgato S, Rocchi M, Gilbert N. Human centromere repositioning activates transcription and opens chromatin fibre structure. Nat Commun 2022; 13:5609. [PMID: 36153345 PMCID: PMC9509383 DOI: 10.1038/s41467-022-33426-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 09/14/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractHuman centromeres appear as constrictions on mitotic chromosomes and form a platform for kinetochore assembly in mitosis. Biophysical experiments led to a suggestion that repetitive DNA at centromeric regions form a compact scaffold necessary for function, but this was revised when neocentromeres were discovered on non-repetitive DNA. To test whether centromeres have a special chromatin structure we have analysed the architecture of a neocentromere. Centromere repositioning is accompanied by RNA polymerase II recruitment and active transcription to form a decompacted, negatively supercoiled domain enriched in ‘open’ chromatin fibres. In contrast, centromerisation causes a spreading of repressive epigenetic marks to surrounding regions, delimited by H3K27me3 polycomb boundaries and divergent genes. This flanking domain is transcriptionally silent and partially remodelled to form ‘compact’ chromatin, similar to satellite-containing DNA sequences, and exhibits genomic instability. We suggest transcription disrupts chromatin to provide a foundation for kinetochore formation whilst compact pericentromeric heterochromatin generates mechanical rigidity.
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17
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Zou Y, Luo J, Tang Z, Fu S. Variations of wheat ( Triticum aestivum L.) chromosomes caused by the 5A chromosomes with complex cytological structure. FRONTIERS IN PLANT SCIENCE 2022; 13:992934. [PMID: 36105696 PMCID: PMC9465395 DOI: 10.3389/fpls.2022.992934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
To study the effects of structural alterations of chromosomes caused by tandem repeats on the meiotic recombination, the wheat (Triticum aestivum L.) 5A chromosomes with different structure from ten wheat cultivars were used to investigate their meiotic recombination using non-denaturing fluorescence in situ hybridization (ND-FISH) technology. Fifteen cross combinations were carried out and they were divided into seven F1 categories. The structural difference between the intercalary regions of the long arms of the two 5A chromosomes (5AL) in the F1 categories III, VI, and VII was greater than that in the categories I and II, subsequently, the recombination frequencies in the distal regions of the 5AL arm in the progenies from the three categories were significantly lower than that from the categories I and II. For the two 5A chromosomes in the F1 categories VI and VII, the structural differences in the distal regions of both of the two arms were greater than that in the categories IV and V. So, the recombination frequencies in the intercalary region of the 5AL arm in the progeny from the categories IV and V were higher than that in the progeny from the categories VI and VII. The breakage of 5A chromosome together with the 5A translocations and the breakage of some other chromosomes were observed in the progeny from the F1 categories V, VI, and VII. These chromosomal variations were not observed in the progenies from the other four F1 categories. In conclusion, the smaller structural difference between the 5A chromosomes in distal regions of the two arms resulted in a higher recombination frequency in interstitial region and vice versa. The 5A chromosome with complex cytological structure can be used to induce genetic variations of wheat genome.
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Affiliation(s)
- Yang Zou
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Provincial Key Laboratory for Plant Genetics and Breeding, Chengdu, China
| | - Jie Luo
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Provincial Key Laboratory for Plant Genetics and Breeding, Chengdu, China
| | - Zongxiang Tang
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Provincial Key Laboratory for Plant Genetics and Breeding, Chengdu, China
| | - Shulan Fu
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Provincial Key Laboratory for Plant Genetics and Breeding, Chengdu, China
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18
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Popay TM, Dixon JR. Coming full circle: On the origin and evolution of the looping model for enhancer-promoter communication. J Biol Chem 2022; 298:102117. [PMID: 35691341 PMCID: PMC9283939 DOI: 10.1016/j.jbc.2022.102117] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 11/05/2022] Open
Abstract
In mammalian organisms, enhancers can regulate transcription from great genomic distances. How enhancers affect distal gene expression has been a major question in the field of gene regulation. One model to explain how enhancers communicate with their target promoters, the chromatin looping model, posits that enhancers and promoters come in close spatial proximity to mediate communication. Chromatin looping has been broadly accepted as a means for enhancer-promoter communication, driven by accumulating in vitro and in vivo evidence. The genome is now known to be folded into a complex 3D arrangement, created and maintained in part by the interplay of the Cohesin complex and the DNA-binding protein CTCF. In the last few years, however, doubt over the relationship between looping and transcriptional activation has emerged, driven by studies finding that only a modest number of genes are perturbed with acute degradation of looping machinery components. In parallel, newer models describing distal enhancer action have also come to prominence. In this article, we explore the emergence and development of the looping model as a means for enhancer-promoter communication and review the contrasting evidence between historical gene-specific and current global data for the role of chromatin looping in transcriptional regulation. We also discuss evidence for alternative models to chromatin looping and their support in the literature. We suggest that, while there is abundant evidence for chromatin looping as a major mechanism for enhancer function, enhancer-promoter communication is likely mediated by more than one mechanism in an enhancer- and context-dependent manner.
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Affiliation(s)
- Tessa M Popay
- Gene Expression Laboratory, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Jesse R Dixon
- Gene Expression Laboratory, The Salk Institute for Biological Studies, La Jolla, California, USA.
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19
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Dwiranti A, Mualifah M, Kartapradja RHDH, Abinawanto A, Salamah A, Fukui K. Insight into magnesium ions effect on chromosome banding and ultrastructure. Microsc Res Tech 2022; 85:3356-3364. [PMID: 35765224 DOI: 10.1002/jemt.24190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 06/04/2022] [Accepted: 06/20/2022] [Indexed: 11/08/2022]
Abstract
Magnesium ion (Mg2+ ) plays a fundamental role in chromosome condensation which is important for genetic material segregation. Studies about the effects of Mg2+ on the overall chromosome structure have been reported. Nevertheless, its effects on the distribution of heterochromatin and euchromatin region have yet to be investigated. The aim of this study was to evaluate the effects of Mg2+ on the banding pattern and ultrastructure of the chromosome. Chromosome analysis was performed using the synchronized HeLa cells. The effect of Mg2+ was evaluated by subjecting the chromosomes to three different solutions, namely XBE5 (containing 5 mM Mg2+ ) as a control, XBE (0 mM Mg2+ ), and 1 mM EDTA as cations-chelator. Chromosome banding was carried out using the GTL-banding technique. The ultrastructure of the chromosomes treated with and without Mg2+ was further obtained using SEM. The results showed a condensed chromosome structure with a clear banding pattern when the chromosomes were treated with a buffer containing 5 mM Mg2+ . In contrast, chromosomes treated with a buffer containing no Mg2+ and those treated with a cations-chelator showed an expanded and fibrous structure with the lower intensity of the banding pattern. Elongation of the chromosome caused by decondensation resulted in the band splitting. The different ultrastructure of the chromosomes treated with and without Mg2+ was obvious under SEM. The results of this study further emphasized the role of Mg2+ on chromosome structure and gave insights into Mg2+ effects on the banding distribution and ultrastructure of the chromosome.
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Affiliation(s)
- Astari Dwiranti
- Cellular and Molecular Mechanisms in Biological System Research Group, Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, Indonesia
| | - Mualifah Mualifah
- Cellular and Molecular Mechanisms in Biological System Research Group, Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, Indonesia
| | | | - Abinawanto Abinawanto
- Cellular and Molecular Mechanisms in Biological System Research Group, Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, Indonesia
| | - Andi Salamah
- Cellular and Molecular Mechanisms in Biological System Research Group, Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, Indonesia
| | - Kiichi Fukui
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
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20
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Nissani N, Ulitsky I. Unique features of transcription termination and initiation at closely spaced tandem human genes. Mol Syst Biol 2022; 18:e10682. [PMID: 35362230 PMCID: PMC8972054 DOI: 10.15252/msb.202110682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 03/09/2022] [Accepted: 03/10/2022] [Indexed: 11/09/2022] Open
Abstract
The synthesis of RNA polymerase II (Pol2) products, which include messenger RNAs or long noncoding RNAs, culminates in transcription termination. How the transcriptional termination of a gene impacts the activity of promoters found immediately downstream of it, and which can be subject to potential transcriptional interference, remains largely unknown. We examined in an unbiased manner the features of the intergenic regions between pairs of 'tandem genes'-closely spaced (< 2 kb) human genes found on the same strand. Intergenic regions separating tandem genes are enriched with guanines and are characterized by binding of several proteins, including AGO1 and AGO2 of the RNA interference pathway. Additionally, we found that Pol2 is particularly enriched in this region, and it is lost upon perturbations affecting splicing or transcriptional elongation. Perturbations of genes involved in Pol2 pausing and R loop biology preferentially affect expression of downstream genes in tandem gene pairs. Overall, we find that features associated with Pol2 pausing and accumulation rather than those associated with avoidance of transcriptional interference are the predominant driving force shaping short tandem intergenic regions.
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Affiliation(s)
- Noa Nissani
- Departments of Biological Regulation and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
| | - Igor Ulitsky
- Departments of Biological Regulation and Molecular NeuroscienceWeizmann Institute of ScienceRehovotIsrael
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21
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Phasor map analysis to investigate Hutchinson-Gilford progeria cell under polarization-resolved optical scanning microscopy. Sci Rep 2022; 12:1679. [PMID: 35102338 PMCID: PMC8803953 DOI: 10.1038/s41598-022-05755-1] [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: 07/06/2021] [Accepted: 01/06/2022] [Indexed: 12/02/2022] Open
Abstract
Polarized light scanning microscopy is a non-invasive and contrast-enhancing technique to investigate anisotropic specimens and chiral organizations. However, such arrangements suffer from insensitivity to confined blend of structures at sub-diffraction level. Here for the first time, we present that the pixel-by-pixel polarization modulation converted to an image phasor approach issues an insightful view of cells to distinguish anomalous subcellular organizations. To this target, we propose an innovative robust way for identifying changes in the chromatin compaction and distortion of nucleus morphology induced by the activation of the lamin-A gene from Hutchinson–Gilford progeria syndrome that induces a strong polarization response. The phasor mapping is evaluated based on the modulation and phase image acquired from a scanning microscope compared to a confocal fluorescence modality of normal cell opposed to the progeria. The method is validated by characterizing polarization response of starch crystalline granules. Additionally, we show that the conversion of the polarization-resolved images into the phasor could further utilized for segmenting specific structures presenting various optical properties under the polarized light. In summary, image phasor analysis offers a distinctly sensitive fast and easy representation of the polarimetric contrast that can pave the way for remote diagnosis of pathological tissues in real-time.
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22
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Nustad HE, Steinsland I, Ollikainen M, Cazaly E, Kaprio J, Benjamini Y, Gervin K, Lyle R. Modeling dependency structures in 450k DNA methylation data. Bioinformatics 2022; 38:885-891. [PMID: 34788815 PMCID: PMC8796368 DOI: 10.1093/bioinformatics/btab774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 11/01/2021] [Accepted: 11/09/2021] [Indexed: 02/04/2023] Open
Abstract
MOTIVATION DNA methylation has been shown to be spatially dependent across chromosomes. Previous studies have focused on the influence of genomic context on the dependency structure, while not considering differences in dependency structure between individuals. RESULTS We modeled spatial dependency with a flexible framework to quantify the dependency structure, focusing on inter-individual differences by exploring the association between dependency parameters and technical and biological variables. The model was applied to a subset of the Finnish Twin Cohort study (N = 1611 individuals). The estimates of the dependency parameters varied considerably across individuals, but were generally consistent across chromosomes within individuals. The variation in dependency parameters was associated with bisulfite conversion plate, zygosity, sex and age. The age differences presumably reflect accumulated environmental exposures and/or accumulated small methylation differences caused by stochastic mitotic events, establishing recognizable, individual patterns more strongly seen in older individuals. AVAILABILITY AND IMPLEMENTATION The twin dataset used in the current study are located in the Biobank of the National Institute for Health and Welfare, Finland. All the biobanked data are publicly available for use by qualified researchers following a standardized application procedure (https://thl.fi/en/web/thl-biobank/for-researchers). A R-script for fitting the dependency structure to publicly available DNA methylation data with the software used in this article is provided in supplementary data. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Haakon E Nustad
- Department of Medical Genetics and Norwegian Sequencing Centre, Oslo University Hospital, 0450 Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, 0372 Oslo, Norway
- Department of Pharmacy, PharmaTox Strategic Research Initiative, University of Oslo, 0371 Oslo, Norway
- Centre for Fertility and Health, Norwegian Institute of Public Health, 0213 Oslo, Norway
| | - Ingelin Steinsland
- Department of Mathematical Sciences, Norwegian University of Science and Technology, 7034 Trondheim, Norway
| | - Miina Ollikainen
- Institute for Molecular Medicine Finland FIMM, Helsinki Institute of Life Science, University of Helsinki, FI-00014 Helsinki, Finland
| | - Emma Cazaly
- Institute for Molecular Medicine Finland FIMM, Helsinki Institute of Life Science, University of Helsinki, FI-00014 Helsinki, Finland
| | - Jaakko Kaprio
- Institute for Molecular Medicine Finland FIMM, Helsinki Institute of Life Science, University of Helsinki, FI-00014 Helsinki, Finland
| | - Yuval Benjamini
- Department of Statistics and Data Science, The Hebrew University, Mount Scopus, Jerusalem 9190501, Israel
| | - Kristina Gervin
- Department of Pharmacy, PharmaTox Strategic Research Initiative, University of Oslo, 0371 Oslo, Norway
- Division of Clinical Neuroscience, Department of Research and Innovation, Oslo University Hospital, 0450 Oslo, Norway
- Pharmacoepidemiology and Drug Safety Research Group, Department of Pharmacy, Faculty of Mathematics and Natural Sciences, University of Oslo, 0363 Oslo, Norway
| | - Robert Lyle
- Department of Medical Genetics and Norwegian Sequencing Centre, Oslo University Hospital, 0450 Oslo, Norway
- Centre for Fertility and Health, Norwegian Institute of Public Health, 0213 Oslo, Norway
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23
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Abstract
Transcription factors (TFs) are essential mediators of epigenetic regulation and modifiers of penetrance. Studies from the past decades have revealed a sub-class of TF that is capable of remodeling closed chromatin states through targeting nucleosomal motifs. This pioneer factor (PF) class of chromatin remodeler is ATP independent in its roles in epigenetic initiation, with nucleosome-motif recognition and association with repressive chromatin regions. Increasing evidence suggests that the fundamental properties of PFs can be coopted in human cancers. We explore the role of PFs in the larger context of tissue-specific epigenetic regulation. Moreover, we highlight an emerging class of chimeric PF derived from translocation partners in human disease and PFs associated with rare tumors. In the age of site-directed genome editing and targeted protein degradation, increasing our understanding of PFs will provide access to next-generation therapy for human disease driven from altered transcriptional circuitry.
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24
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Abstract
Mammalian genomes have distinct levels of spatial organization and structure that have been hypothesized to play important roles in transcription regulation. Although much has been learned about these architectural features with ensemble techniques, single-cell studies are showing a new universal trend: Genomes are stochastic and dynamic at every level of organization. Stochastic gene expression, on the other hand, has been studied for years. In this review, we probe whether there is a causative link between the two phenomena. We specifically discuss the functionality of chromatin state, topologically associating domains (TADs), and enhancer biology in light of their stochastic nature and their specific roles in stochastic gene expression. We highlight persistent fundamental questions in this area of research.
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Affiliation(s)
- Christopher H Bohrer
- Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Daniel R Larson
- Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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25
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Brackley CA, Gilbert N, Michieletto D, Papantonis A, Pereira MCF, Cook PR, Marenduzzo D. Complex small-world regulatory networks emerge from the 3D organisation of the human genome. Nat Commun 2021; 12:5756. [PMID: 34599163 PMCID: PMC8486811 DOI: 10.1038/s41467-021-25875-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/30/2021] [Indexed: 01/01/2023] Open
Abstract
The discovery that overexpressing one or a few critical transcription factors can switch cell state suggests that gene regulatory networks are relatively simple. In contrast, genome-wide association studies (GWAS) point to complex phenotypes being determined by hundreds of loci that rarely encode transcription factors and which individually have small effects. Here, we use computer simulations and a simple fitting-free polymer model of chromosomes to show that spatial correlations arising from 3D genome organisation naturally lead to stochastic and bursty transcription as well as complex small-world regulatory networks (where the transcriptional activity of each genomic region subtly affects almost all others). These effects require factors to be present at sub-saturating levels; increasing levels dramatically simplifies networks as more transcription units are pressed into use. Consequently, results from GWAS can be reconciled with those involving overexpression. We apply this pan-genomic model to predict patterns of transcriptional activity in whole human chromosomes, and, as an example, the effects of the deletion causing the diGeorge syndrome.
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Affiliation(s)
- C A Brackley
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK
| | - N Gilbert
- MRC Human Genetics Unit, MRC Institute of Genetics & Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - D Michieletto
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK
- MRC Human Genetics Unit, MRC Institute of Genetics & Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK
| | - A Papantonis
- Institute of Pathology, University Medical Center, Georg-August University of Göttingen, 37075, Göttingen, Germany
| | - M C F Pereira
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK
| | - P R Cook
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - D Marenduzzo
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK.
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26
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27
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Ishihara S, Sasagawa Y, Kameda T, Yamashita H, Umeda M, Kotomura N, Abe M, Shimono Y, Nikaido I. Local states of chromatin compaction at transcription start sites control transcription levels. Nucleic Acids Res 2021; 49:8007-8023. [PMID: 34233004 PMCID: PMC8373074 DOI: 10.1093/nar/gkab587] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 06/12/2021] [Accepted: 06/30/2021] [Indexed: 11/16/2022] Open
Abstract
The ‘open’ and ‘compact’ regions of chromatin are considered to be regions of active and silent transcription, respectively. However, individual genes produce transcripts at different levels, suggesting that transcription output does not depend on the simple open-compact conversion of chromatin, but on structural variations in chromatin itself, which so far have remained elusive. In this study, weakly crosslinked chromatin was subjected to sedimentation velocity centrifugation, which fractionated the chromatin according to its degree of compaction. Open chromatin remained in upper fractions, while compact chromatin sedimented to lower fractions depending on the level of nucleosome assembly. Although nucleosomes were evenly detected in all fractions, histone H1 was more highly enriched in the lower fractions. H1 was found to self-associate and crosslinked to histone H3, suggesting that H1 bound to H3 interacts with another H1 in an adjacent nucleosome to form compact chromatin. Genome-wide analyses revealed that nearly the entire genome consists of compact chromatin without differences in compaction between repeat and non-repeat sequences; however, active transcription start sites (TSSs) were rarely found in compact chromatin. Considering the inverse correlation between chromatin compaction and RNA polymerase binding at TSSs, it appears that local states of chromatin compaction determine transcription levels.
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Affiliation(s)
- Satoru Ishihara
- Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
| | - Yohei Sasagawa
- Laboratory for Bioinformatics Research, RIKEN Center for Biosystems Dynamics Research, Wako, Saitama 351-0198, Japan.,Functional Genome Informatics, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Takeru Kameda
- Laboratory for Bioinformatics Research, RIKEN Center for Biosystems Dynamics Research, Wako, Saitama 351-0198, Japan.,Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Hayato Yamashita
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Mana Umeda
- Laboratory for Bioinformatics Research, RIKEN Center for Biosystems Dynamics Research, Wako, Saitama 351-0198, Japan
| | - Naoe Kotomura
- Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
| | - Masayuki Abe
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Yohei Shimono
- Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
| | - Itoshi Nikaido
- Laboratory for Bioinformatics Research, RIKEN Center for Biosystems Dynamics Research, Wako, Saitama 351-0198, Japan.,Functional Genome Informatics, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510, Japan.,Master's/Doctoral Program in Life Science Innovation (Bioinformatics), Degree Programs in Systems and Information Engineering, Graduate School of Science and Technology, University of Tsukuba, Wako, Saitama 351-0198, Japan
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28
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Xie L, Liu Z. Single-cell imaging of genome organization and dynamics. Mol Syst Biol 2021; 17:e9653. [PMID: 34232558 PMCID: PMC8262488 DOI: 10.15252/msb.20209653] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/13/2021] [Accepted: 04/23/2021] [Indexed: 12/28/2022] Open
Abstract
Probing the architecture, mechanism, and dynamics of genome folding is fundamental to our understanding of genome function in homeostasis and disease. Most chromosome conformation capture studies dissect the genome architecture with population- and time-averaged snapshots and thus have limited capabilities to reveal 3D nuclear organization and dynamics at the single-cell level. Here, we discuss emerging imaging techniques ranging from light microscopy to electron microscopy that enable investigation of genome folding and dynamics at high spatial and temporal resolution. Results from these studies complement genomic data, unveiling principles underlying the spatial arrangement of the genome and its potential functional links to diverse biological activities in the nucleus.
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Affiliation(s)
- Liangqi Xie
- Janelia Research CampusHoward Hughes Medical InstituteAshburnVAUSA
| | - Zhe Liu
- Janelia Research CampusHoward Hughes Medical InstituteAshburnVAUSA
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29
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Tachiwana H, Dacher M, Maehara K, Harada A, Seto Y, Katayama R, Ohkawa Y, Kimura H, Kurumizaka H, Saitoh N. Chromatin structure-dependent histone incorporation revealed by a genome-wide deposition assay. eLife 2021; 10:66290. [PMID: 33970102 PMCID: PMC8110306 DOI: 10.7554/elife.66290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 04/05/2021] [Indexed: 12/25/2022] Open
Abstract
In eukaryotes, histone variant distribution within the genome is the key epigenetic feature. To understand how each histone variant is targeted to the genome, we developed a new method, the RhIP (Reconstituted histone complex Incorporation into chromatin of Permeabilized cell) assay, in which epitope-tagged histone complexes are introduced into permeabilized cells and incorporated into their chromatin. Using this method, we found that H3.1 and H3.3 were incorporated into chromatin in replication-dependent and -independent manners, respectively. We further found that the incorporation of histones H2A and H2A.Z mainly occurred at less condensed chromatin (open), suggesting that condensed chromatin (closed) is a barrier for histone incorporation. To overcome this barrier, H2A, but not H2A.Z, uses a replication-coupled deposition mechanism. Our study revealed that the combination of chromatin structure and DNA replication dictates the differential histone deposition to maintain the epigenetic chromatin states.
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Affiliation(s)
- Hiroaki Tachiwana
- Division of Cancer Biology, The Cancer Institute of Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Mariko Dacher
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Kazumitsu Maehara
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Akihito Harada
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Yosuke Seto
- Division of Experimental Chemotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Ryohei Katayama
- Division of Experimental Chemotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Yasuyuki Ohkawa
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Hiroshi Kimura
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Noriko Saitoh
- Division of Cancer Biology, The Cancer Institute of Japanese Foundation for Cancer Research, Tokyo, Japan
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30
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Bernardi G. The "Genomic Code": DNA Pervasively Moulds Chromatin Structures Leaving no Room for "Junk". Life (Basel) 2021; 11:342. [PMID: 33924668 PMCID: PMC8070607 DOI: 10.3390/life11040342] [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: 03/01/2021] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 02/07/2023] Open
Abstract
The chromatin of the human genome was analyzed at three DNA size levels. At the first, compartment level, two "gene spaces" were found many years ago: A GC-rich, gene-rich "genome core" and a GC-poor, gene-poor "genome desert", the former corresponding to open chromatin centrally located in the interphase nucleus, the latter to closed chromatin located peripherally. This bimodality was later confirmed and extended by the discoveries (1) of LADs, the Lamina-Associated Domains, and InterLADs; (2) of two "spatial compartments", A and B, identified on the basis of chromatin interactions; and (3) of "forests and prairies" characterized by high and low CpG islands densities. Chromatin compartments were shown to be associated with the compositionally different, flat and single- or multi-peak DNA structures of the two, GC-poor and GC-rich, "super-families" of isochores. At the second, sub-compartment, level, chromatin corresponds to flat isochores and to isochore loops (due to compositional DNA gradients) that are susceptible to extrusion. Finally, at the short-sequence level, two sets of sequences, GC-poor and GC-rich, define two different nucleosome spacings, a short one and a long one. In conclusion, chromatin structures are moulded according to a "genomic code" by DNA sequences that pervade the genome and leave no room for "junk".
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Affiliation(s)
- Giorgio Bernardi
- Science Department, Roma Tre University, Viale Marconi 446, 00146 Rome, Italy; ; Tel.: +39-33-540-5892
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
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31
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Sebestyén E, Marullo F, Lucini F, Petrini C, Bianchi A, Valsoni S, Olivieri I, Antonelli L, Gregoretti F, Oliva G, Ferrari F, Lanzuolo C. SAMMY-seq reveals early alteration of heterochromatin and deregulation of bivalent genes in Hutchinson-Gilford Progeria Syndrome. Nat Commun 2020; 11:6274. [PMID: 33293552 PMCID: PMC7722762 DOI: 10.1038/s41467-020-20048-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 11/05/2020] [Indexed: 12/14/2022] Open
Abstract
Hutchinson-Gilford progeria syndrome is a genetic disease caused by an aberrant form of Lamin A resulting in chromatin structure disruption, in particular by interfering with lamina associated domains. Early molecular alterations involved in chromatin remodeling have not been identified thus far. Here, we present SAMMY-seq, a high-throughput sequencing-based method for genome-wide characterization of heterochromatin dynamics. Using SAMMY-seq, we detect early stage alterations of heterochromatin structure in progeria primary fibroblasts. These structural changes do not disrupt the distribution of H3K9me3 in early passage cells, thus suggesting that chromatin rearrangements precede H3K9me3 alterations described at later passages. On the other hand, we observe an interplay between changes in chromatin accessibility and Polycomb regulation, with site-specific H3K27me3 variations and transcriptional dysregulation of bivalent genes. We conclude that the correct assembly of lamina associated domains is functionally connected to the Polycomb repression and rapidly lost in early molecular events of progeria pathogenesis.
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Affiliation(s)
- Endre Sebestyén
- IFOM, The FIRC Institute of Molecular Oncology, Milan, Italy
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | - Fabrizia Marullo
- Institute of Cell Biology and Neurobiology, National Research Council, Rome, Italy
| | - Federica Lucini
- Istituto Nazionale Genetica Molecolare "Romeo ed Enrica Invernizzi", Milan, Italy
| | | | - Andrea Bianchi
- Institute of Cell Biology and Neurobiology, National Research Council, Rome, Italy
- IRCCS Santa Lucia Foundation, Rome, Italy
| | - Sara Valsoni
- IRCCS Santa Lucia Foundation, Rome, Italy
- Institute for High Performance Computing and Networking, National Research Council, Naples, Italy
| | - Ilaria Olivieri
- Institute of Cell Biology and Neurobiology, National Research Council, Rome, Italy
| | - Laura Antonelli
- Institute for High Performance Computing and Networking, National Research Council, Naples, Italy
| | - Francesco Gregoretti
- Institute for High Performance Computing and Networking, National Research Council, Naples, Italy
| | - Gennaro Oliva
- Institute for High Performance Computing and Networking, National Research Council, Naples, Italy
| | - Francesco Ferrari
- IFOM, The FIRC Institute of Molecular Oncology, Milan, Italy.
- Institute of Molecular Genetics, National Research Council, Pavia, Italy.
| | - Chiara Lanzuolo
- Istituto Nazionale Genetica Molecolare "Romeo ed Enrica Invernizzi", Milan, Italy.
- Institute of Biomedical Technologies, National Research Council, Milan, Italy.
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32
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Abdulhay NJ, McNally CP, Hsieh LJ, Kasinathan S, Keith A, Estes LS, Karimzadeh M, Underwood JG, Goodarzi H, Narlikar GJ, Ramani V. Massively multiplex single-molecule oligonucleosome footprinting. eLife 2020; 9:59404. [PMID: 33263279 PMCID: PMC7735760 DOI: 10.7554/elife.59404] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 11/24/2020] [Indexed: 01/10/2023] Open
Abstract
Our understanding of the beads-on-a-string arrangement of nucleosomes has been built largely on high-resolution sequence-agnostic imaging methods and sequence-resolved bulk biochemical techniques. To bridge the divide between these approaches, we present the single-molecule adenine methylated oligonucleosome sequencing assay (SAMOSA). SAMOSA is a high-throughput single-molecule sequencing method that combines adenine methyltransferase footprinting and single-molecule real-time DNA sequencing to natively and nondestructively measure nucleosome positions on individual chromatin fibres. SAMOSA data allows unbiased classification of single-molecular 'states' of nucleosome occupancy on individual chromatin fibres. We leverage this to estimate nucleosome regularity and spacing on single chromatin fibres genome-wide, at predicted transcription factor binding motifs, and across human epigenomic domains. Our analyses suggest that chromatin is comprised of both regular and irregular single-molecular oligonucleosome patterns that differ subtly in their relative abundance across epigenomic domains. This irregularity is particularly striking in constitutive heterochromatin, which has typically been viewed as a conformationally static entity. Our proof-of-concept study provides a powerful new methodology for studying nucleosome organization at a previously intractable resolution and offers up new avenues for modeling and visualizing higher order chromatin structure.
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Affiliation(s)
- Nour J Abdulhay
- Department of Biochemistry & Biophysics, University of California San Francisco, San Francisco, United States
| | - Colin P McNally
- Department of Biochemistry & Biophysics, University of California San Francisco, San Francisco, United States
| | - Laura J Hsieh
- Department of Biochemistry & Biophysics, University of California San Francisco, San Francisco, United States
| | | | - Aidan Keith
- Department of Biochemistry & Biophysics, University of California San Francisco, San Francisco, United States
| | - Laurel S Estes
- Department of Biochemistry & Biophysics, University of California San Francisco, San Francisco, United States
| | - Mehran Karimzadeh
- Department of Biochemistry & Biophysics, University of California San Francisco, San Francisco, United States.,Vector Institute, Toronto, United States
| | | | - Hani Goodarzi
- Department of Biochemistry & Biophysics, University of California San Francisco, San Francisco, United States.,Bakar Computational Health Sciences Institute, San Francisco, United States
| | - Geeta J Narlikar
- Department of Biochemistry & Biophysics, University of California San Francisco, San Francisco, United States
| | - Vijay Ramani
- Department of Biochemistry & Biophysics, University of California San Francisco, San Francisco, United States.,Bakar Computational Health Sciences Institute, San Francisco, United States
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33
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Kwon S, Sung BJ. History-dependent nonequilibrium conformations of a highly confined polymer globule in a sphere. Phys Rev E 2020; 102:022501. [PMID: 32942375 DOI: 10.1103/physreve.102.022501] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/28/2020] [Indexed: 11/07/2022]
Abstract
Chromatin undergoes condensation-decondensation processes repeatedly during its cell lifetime. The spatial organization of chromatin in nucleus resembles the fractal globule, of which structure significantly differs from an equilibrium polymer globule. There have been efforts to develop a polymer globule model to describe the fractal globulelike structure of tightly packed chromatin in nucleus. However, the transition pathway of a polymer toward a globular state has been often ignored. Because biological systems are intrinsically in nonequilibrium states, the transition pathway that the chromatin would take before reaching the densely packaged globule should be of importance. In this study, by employing a simple polymer model and Langevin dynamics simulations, we investigate the conformational transition of a single polymer from a swollen coil to a compact globule. We aim to elucidate the effect of transition pathways on the final globular structure. We show that a fast collapse induces a nonequilibrium structure even without a specific intramolecular interaction and that its relaxation toward an equilibrium globule is extremely slow. Due to a strong confinement, the fractal globule never relaxes into an equilibrium state during our simulations such that the globular structure becomes dependent on the transition pathway.
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Affiliation(s)
- Seulki Kwon
- Department of Chemistry, Sogang University, Seoul 121-742, Republic of Korea
| | - Bong June Sung
- Department of Chemistry, Sogang University, Seoul 121-742, Republic of Korea
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34
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Sanulli S, J Narlikar G. Liquid-like interactions in heterochromatin: Implications for mechanism and regulation. Curr Opin Cell Biol 2020; 64:90-96. [PMID: 32434105 DOI: 10.1016/j.ceb.2020.03.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/12/2020] [Accepted: 03/29/2020] [Indexed: 12/14/2022]
Abstract
A large portion of the eukaryotic genome is packed into heterochromatin, a versatile platform that is essential to maintain genome stability. Often associated with a compact and transcriptionally repressed chromatin state, heterochromatin was earlier considered a static and locked compartment. However, cumulative findings over the last 17 years have suggested that heterochromatin displays dynamics at different timescales and size scales. These dynamics are thought to be essential for the regulation of heterochromatin. This review illustrates how the key principles underlying heterochromatin structure and function have evolved along the years and summarizes the discoveries that have led to the continuous revision of these principles. Using heterochromatin protein 1-mediated heterochromatin as a context, we discuss a novel paradigm for heterochromatin organization based on two emerging concepts, phase separation and nucleosome structural plasticity. We also examine the broader implications of this paradigm for chromatin organization and regulation beyond heterochromatin.
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Affiliation(s)
- Serena Sanulli
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA.
| | - Geeta J Narlikar
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, 94158, USA
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35
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Bendandi A, Dante S, Zia SR, Diaspro A, Rocchia W. Chromatin Compaction Multiscale Modeling: A Complex Synergy Between Theory, Simulation, and Experiment. Front Mol Biosci 2020; 7:15. [PMID: 32158765 PMCID: PMC7051991 DOI: 10.3389/fmolb.2020.00015] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 01/27/2020] [Indexed: 12/24/2022] Open
Abstract
Understanding the mechanisms that trigger chromatin compaction, its patterns, and the factors they depend on, is a fundamental and still open question in Biology. Chromatin compacts and reinforces DNA and is a stable but dynamic structure, to make DNA accessible to proteins. In recent years, computational advances have provided larger amounts of data and have made large-scale simulations more viable. Experimental techniques for the extraction and reconstitution of chromatin fibers have improved, reinvigorating theoretical and experimental interest in the topic and stimulating debate on points previously considered as certainties regarding chromatin. A great assortment of approaches has emerged, from all-atom single-nucleosome or oligonucleosome simulations to various degrees of coarse graining, to polymer models, to fractal-like structures and purely topological models. Different fiber-start patterns have been studied in theory and experiment, as well as different linker DNA lengths. DNA is a highly charged macromolecule, making ionic and electrostatic interactions extremely important for chromatin topology and dynamics. Indeed, the repercussions of varying ionic concentration have been extensively examined at the computational level, using all-atom, coarse-grained, and continuum techniques. The presence of high-curvature AT-rich segments in DNA can cause conformational variations, attesting to the fact that the role of DNA is both structural and electrostatic. There have been some tentative attempts to describe the force fields governing chromatin conformational changes and the energy landscapes of these transitions, but the intricacy of the system has hampered reaching a consensus. The study of chromatin conformations is an intrinsically multiscale topic, influenced by a wide range of biological and physical interactions, spanning from the atomic to the chromosome level. Therefore, powerful modeling techniques and carefully planned experiments are required for an overview of the most relevant phenomena and interactions. The topic provides fertile ground for interdisciplinary studies featuring a synergy between theoretical and experimental scientists from different fields and the cross-validation of respective results, with a multi-scale perspective. Here, we summarize some of the most representative approaches, and focus on the importance of electrostatics and solvation, often overlooked aspects of chromatin modeling.
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Affiliation(s)
- Artemi Bendandi
- Physics Department, University of Genoa, Genoa, Italy
- Nanophysics & NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Silvia Dante
- Nanophysics & NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Syeda Rehana Zia
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Alberto Diaspro
- Physics Department, University of Genoa, Genoa, Italy
- Nanophysics & NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Walter Rocchia
- Concept Lab, Istituto Italiano di Tecnologia, Genoa, Italy
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Centromere chromatin structure - Lessons from neocentromeres. Exp Cell Res 2020; 389:111899. [PMID: 32044308 DOI: 10.1016/j.yexcr.2020.111899] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/01/2020] [Accepted: 02/07/2020] [Indexed: 11/22/2022]
Abstract
Centromeres are highly specialized genomic loci that function during mitosis to maintain genome stability. Formed primarily on repetitive α-satellite DNA sequence characterisation of native centromeric chromatin structure has remained challenging. Fortuitously, neocentromeres are formed on a unique DNA sequence and represent an excellent model to interrogate centromeric chromatin structure. This review uncovers the specific findings from independent neocentromere studies that have advanced our understanding of canonical centromere chromatin structure.
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Abstract
Chromosome organisation is increasingly recognised as an essential component of genome regulation, cell fate and cell health. Within the realm of transposable elements (TEs) however, the spatial information of how genomes are folded is still only rarely integrated in experimental studies or accounted for in modelling. Whilst polymer physics is recognised as an important tool to understand the mechanisms of genome folding, in this commentary we discuss its potential applicability to aspects of TE biology. Based on recent works on the relationship between genome organisation and TE integration, we argue that existing polymer models may be extended to create a predictive framework for the study of TE integration patterns. We suggest that these models may offer orthogonal and generic insights into the integration profiles (or "topography") of TEs across organisms. In addition, we provide simple polymer physics arguments and preliminary molecular dynamics simulations of TEs inserting into heterogeneously flexible polymers. By considering this simple model, we show how polymer folding and local flexibility may generically affect TE integration patterns. The preliminary discussion reported in this commentary is aimed to lay the foundations for a large-scale analysis of TE integration dynamics and topography as a function of the three-dimensional host genome.
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Nizovtseva EV, Polikanov YS, Kulaeva OI, Clauvelin N, Postnikov YV, Olson WK, Studitsky VM. [Opposite Effects of Histone H1 and HMGN5 Protein on Distant Interactions in Chromatin]. Mol Biol (Mosk) 2020; 53:1038-1048. [PMID: 31876282 DOI: 10.1134/s0026898419060132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 06/14/2019] [Indexed: 11/23/2022]
Abstract
Transcriptional enhancers in the cell nuclei typically interact with the target promoters in cis over long stretches of chromatin, but the mechanism of this communication remains unknown. Previously we have developed a defined in vitro system for quantitative analysis of the rate of distant enhancer-promoter communication (EPC) and have shown that the chromatin fibers maintain efficient distant EPC in cis. Here we investigate the roles of linker histone H1 and HMGN5 protein in EPC. A considerable negative effect of histone H1 on EPC depending on its C- and N-tails was shown. Protein HMGN5 that affects chromatin compaction and is associated with active chromatin counteracts EPC inhibition by H1. The data suggest that the efficiency of the interaction between the enhancer and the promoter depends on the structure and dynamics of the chromatin fiber localized between them and can be regulated by proteins associated with chromatin.
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Affiliation(s)
- E V Nizovtseva
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA, 19422 USA
| | - Y S Polikanov
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607 USA.,Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, Chicago, IL 60607 USA
| | - O I Kulaeva
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA, 19422 USA
| | - N Clauvelin
- Department of Chemistry and Chemical Biology, BioMaPS Institute for Quantitative Biology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854 USA
| | - Y V Postnikov
- Protein Section, Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892 USA
| | - W K Olson
- Department of Chemistry and Chemical Biology, BioMaPS Institute for Quantitative Biology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854 USA
| | - V M Studitsky
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA, 19422 USA.,Faculty of Biology, Moscow State University, Moscow, 119991 Russia.,
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Abstract
Understanding how the genome is organized within the cell nucleus is increasingly recognized to be important to understand gene regulation. In 3D DNA fluorescence in situ hybridization (3D DNA FISH) labeled probes complementary to specific loci of interest are hybridized to the genome. The samples are then imaged using fluorescence microscopy, collecting z-stacks through the nuclei, and the relative positions of the hybridized probes are analyzed in the reconstructed 3D images. In this way 3D DNA FISH provides a powerful tool to interrogate how the organization of specific genomic loci changes in response to stimuli. This chapter describes protocols which have allowed us to produce consistent data in cultured cells and paraffin-embedded tissue sections.
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Affiliation(s)
- Alasdair Jubb
- Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge, UK. .,CRUK Cambridge Institute, University of Cambridge, Cambridge, UK.
| | - Shelagh Boyle
- MRC Human Genetics Unit, MRC Institute of Genetics & Molecular Medicine, University of Edinburgh, Edinburgh, UK
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40
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Nizovtseva EV, Polikanov YS, Kulaeva OI, Clauvelin N, Postnikov YV, Olson WK, Studitsky VM. Opposite Effects of Histone H1 and HMGN5 Protein on Distant Interactions in Chromatin. Mol Biol 2019. [DOI: 10.1134/s002689331906013x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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41
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Gebert D, Zischler H, Rosenkranz D. Primate piRNA Cluster Evolution Suggests Limited Relevance of Pseudogenes in piRNA-Mediated Gene Regulation. Genome Biol Evol 2019; 11:1088-1104. [PMID: 30888404 PMCID: PMC6461890 DOI: 10.1093/gbe/evz060] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2019] [Indexed: 12/11/2022] Open
Abstract
PIWI proteins and their guiding Piwi-interacting (pi-) RNAs direct the silencing of target nucleic acids in the animal germline and soma. Although in mammal testes fetal piRNAs are involved in extensive silencing of transposons, pachytene piRNAs have additionally been shown to act in post-transcriptional gene regulation. The bulk of pachytene piRNAs is produced from large genomic loci, named piRNA clusters. Recently, the presence of reversed pseudogenes within piRNA clusters prompted the idea that piRNAs derived from such sequences might direct regulation of their parent genes. Here, we examine primate piRNA clusters and integrated pseudogenes in a comparative approach to gain a deeper understanding about mammalian piRNA cluster evolution and the presumed gene-regulatory role of pseudogene-derived piRNAs. Initially, we provide a broad analysis of the evolutionary relationships of piRNA clusters and their differential activity among six primate species. Subsequently, we show that pseudogenes in reserve orientation relative to piRNA cluster transcription direction generally do not exhibit signs of selection pressure and cause weakly conserved targeting of homologous genes among species, suggesting a lack of functional constraints and thus only a minor significance for gene regulation in most cases. Finally, we report that piRNA-producing loci generally tend to be located in active genomic regions with elevated gene and pseudogene density. Thus, we conclude that the presence of most pseudogenes in piRNA clusters might be regarded as a byproduct of piRNA cluster generation, whereas this does not exclude that some pseudogenes nevertheless play critical roles in individual cases.
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Affiliation(s)
- Daniel Gebert
- Institute of Organismic and Molecular Evolution, Anthropology, Johannes Gutenberg University, Mainz, Germany
| | - Hans Zischler
- Institute of Organismic and Molecular Evolution, Anthropology, Johannes Gutenberg University, Mainz, Germany
| | - David Rosenkranz
- Institute of Organismic and Molecular Evolution, Anthropology, Johannes Gutenberg University, Mainz, Germany
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Poulet A, Li B, Dubos T, Rivera-Mulia JC, Gilbert DM, Qin ZS. RT States: systematic annotation of the human genome using cell type-specific replication timing programs. Bioinformatics 2019; 35:2167-2176. [PMID: 30475980 PMCID: PMC6681175 DOI: 10.1093/bioinformatics/bty957] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/05/2018] [Accepted: 11/21/2018] [Indexed: 12/20/2022] Open
Abstract
MOTIVATION The replication timing (RT) program has been linked to many key biological processes including cell fate commitment, 3D chromatin organization and transcription regulation. Significant technology progress now allows to characterize the RT program in the entire human genome in a high-throughput and high-resolution fashion. These experiments suggest that RT changes dynamically during development in coordination with gene activity. Since RT is such a fundamental biological process, we believe that an effective quantitative profile of the local RT program from a diverse set of cell types in various developmental stages and lineages can provide crucial biological insights for a genomic locus. RESULTS In this study, we explored recurrent and spatially coherent combinatorial profiles from 42 RT programs collected from multiple lineages at diverse differentiation states. We found that a Hidden Markov Model with 15 hidden states provide a good model to describe these genome-wide RT profiling data. Each of the hidden state represents a unique combination of RT profiles across different cell types which we refer to as 'RT states'. To understand the biological properties of these RT states, we inspected their relationship with chromatin states, gene expression, functional annotation and 3D chromosomal organization. We found that the newly defined RT states possess interesting genome-wide functional properties that add complementary information to the existing annotation of the human genome. AVAILABILITY AND IMPLEMENTATION R scripts for inferring HMM models and Perl scripts for further analysis are available https://github.com/PouletAxel/script_HMM_Replication_timing. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Axel Poulet
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Ben Li
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | | | - Juan Carlos Rivera-Mulia
- Department of Biological Science, Center for Genomics and Personalized Medicine, Florida State University, Tallahassee, FL, USA
| | - David M Gilbert
- Department of Biological Science, Center for Genomics and Personalized Medicine, Florida State University, Tallahassee, FL, USA
| | - Zhaohui S Qin
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA, USA
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43
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Bickmore WA. Patterns in the genome. Heredity (Edinb) 2019; 123:50-57. [PMID: 31189906 DOI: 10.1038/s41437-019-0220-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/17/2019] [Accepted: 03/20/2019] [Indexed: 12/23/2022] Open
Abstract
The human genome is not randomly organised, with respect to both the linear organisation of the DNA sequence along chromosomes and to the spatial organisation of chromosomes in the cell nucleus. Here I discuss how these patterns of sequence organisation were first discovered by molecular biologists and how they relate to the patterns revealed decades earlier by cytogeneticists and manifest as chromosome bands.
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Affiliation(s)
- Wendy A Bickmore
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Crewe Road, Edinburgh, EH42XU, UK.
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44
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Maeshima K, Ide S, Babokhov M. Dynamic chromatin organization without the 30-nm fiber. Curr Opin Cell Biol 2019; 58:95-104. [DOI: 10.1016/j.ceb.2019.02.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 02/08/2019] [Accepted: 02/14/2019] [Indexed: 12/24/2022]
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45
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Nicetto D, Zaret KS. Role of H3K9me3 heterochromatin in cell identity establishment and maintenance. Curr Opin Genet Dev 2019; 55:1-10. [PMID: 31103921 DOI: 10.1016/j.gde.2019.04.013] [Citation(s) in RCA: 148] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 03/18/2019] [Accepted: 04/15/2019] [Indexed: 01/17/2023]
Abstract
Compacted, transcriptionally repressed chromatin, referred to as heterochromatin, represents a major fraction of the higher eukaryotic genome and exerts pivotal functions of silencing repetitive elements, maintenance of genome stability, and control of gene expression. Among the different histone post-translational modifications (PTMs) associated with heterochromatin, tri-methylation of lysine 9 on histone H3 (H3K9me3) is gaining increased attention. Besides its known role in repressing repetitive elements and non-coding portions of the genome, recent observations indicate H3K9me3 as an important player in silencing lineage-inappropriate genes. The ability of H3K9me3 to influence cell identity challenges the original concept of H3K9me3-marked heterochromatin as mainly a constitutive type of chromatin and provides a further level of understanding of how to modulate cell fate control. Here, we summarize the role of H3K9me3 marked heterochromatin and its dynamics in establishing and maintaining cellular identity.
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Affiliation(s)
- Dario Nicetto
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA; Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA; Dept. Cell and Developmental, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
| | - Kenneth S Zaret
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA; Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA; Dept. Cell and Developmental, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
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46
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Michieletto D, Gilbert N. Role of nuclear RNA in regulating chromatin structure and transcription. Curr Opin Cell Biol 2019; 58:120-125. [PMID: 31009871 PMCID: PMC6694202 DOI: 10.1016/j.ceb.2019.03.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/10/2019] [Accepted: 03/13/2019] [Indexed: 12/31/2022]
Abstract
The importance of three-dimensional chromatin organisation in genome regulation has never been clearer. But in spite of the enormous technological advances to probe chromatin organisation in vivo, there is still a lack of mechanistic understanding of how such an arrangement is achieved. Here we review emerging evidence pointing to an intriguing role of nuclear RNA in shaping large-scale chromatin structure and regulating genome function. We suggest this role may be achieved through the formation of a dynamic nuclear mesh that can exploit ATP-driven processes and phase separation of RNA-binding proteins to tune its assembly and material properties.
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Affiliation(s)
- Davide Michieletto
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK; School of Physics and Astronomy, University of Edinburgh, EH9 3FD, UK
| | - Nick Gilbert
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK.
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47
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Gilbert N. Biophysical regulation of local chromatin structure. Curr Opin Genet Dev 2019; 55:66-75. [DOI: 10.1016/j.gde.2019.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/31/2019] [Accepted: 06/02/2019] [Indexed: 10/26/2022]
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48
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Illingworth RS. Chromatin folding and nuclear architecture: PRC1 function in 3D. Curr Opin Genet Dev 2019; 55:82-90. [PMID: 31323466 PMCID: PMC6859790 DOI: 10.1016/j.gde.2019.06.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 12/20/2022]
Abstract
Embryonic development requires the intricate balance between the expansion and specialisation of defined cell types in time and space. The gene expression programmes that underpin this balance are regulated, in part, by modulating the chemical and structural state of chromatin. Polycomb repressive complexes (PRCs), a family of essential developmental regulators, operate at this level to stabilise or perpetuate a repressed but transcriptionally poised chromatin configuration. This dynamic state is required to control the timely initiation of productive gene transcription during embryonic development. The two major PRCs cooperate to target the genome, but it is PRC1 that appears to be the primary effector that controls gene expression. In this review I will discuss recent findings relating to how PRC1 alters chromatin accessibility, folding and global 3D nuclear organisation to control gene transcription.
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Affiliation(s)
- Robert S Illingworth
- MRC Centre for Regenerative Medicine, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh BioQuarter, 5 Little France Drive, Edinburgh, EH16 4UU, United Kingdom.
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49
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Shimada M, Chen WY, Nakadai T, Onikubo T, Guermah M, Rhodes D, Roeder RG. Gene-Specific H1 Eviction through a Transcriptional Activator→p300→NAP1→H1 Pathway. Mol Cell 2019; 74:268-283.e5. [PMID: 30902546 DOI: 10.1016/j.molcel.2019.02.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 01/07/2019] [Accepted: 02/12/2019] [Indexed: 02/03/2023]
Abstract
Linker histone H1 has been correlated with transcriptional inhibition, but the mechanistic basis of the inhibition and its reversal during gene activation has remained enigmatic. We report that H1-compacted chromatin, reconstituted in vitro, blocks transcription by abrogating core histone modifications by p300 but not activator and p300 binding. Transcription from H1-bound chromatin is elicited by the H1 chaperone NAP1, which is recruited in a gene-specific manner through direct interactions with activator-bound p300 that facilitate core histone acetylation (by p300) and concomitant eviction of H1 and H2A-H2B. An analysis in B cells confirms the strong dependency on NAP1-mediated H1 eviction for induction of the silent CD40 gene and further demonstrates that H1 eviction, seeded by activator-p300-NAP1-H1 interactions, is propagated over a CCCTC-binding factor (CTCF)-demarcated region through a distinct mechanism that also involves NAP1. Our results confirm direct transcriptional inhibition by H1 and establish a gene-specific H1 eviction mechanism through an activator→p300→NAP1→H1 pathway.
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Affiliation(s)
- Miho Shimada
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY 10065, USA
| | - Wei-Yi Chen
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY 10065, USA; Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan; Cancer Progression Research Center, National Yang-Ming University, Taipei 112, Taiwan
| | - Tomoyoshi Nakadai
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY 10065, USA
| | - Takashi Onikubo
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY 10065, USA
| | - Mohamed Guermah
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY 10065, USA
| | - Daniela Rhodes
- NTU Institute of Structural Biology and School of Biological Sciences, Nanyang Technological University, Singapore 636921, Singapore
| | - Robert G Roeder
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY 10065, USA.
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50
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Fritz AJ, Sehgal N, Pliss A, Xu J, Berezney R. Chromosome territories and the global regulation of the genome. Genes Chromosomes Cancer 2019; 58:407-426. [PMID: 30664301 DOI: 10.1002/gcc.22732] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/11/2019] [Accepted: 01/12/2019] [Indexed: 12/29/2022] Open
Abstract
Spatial positioning is a fundamental principle governing nuclear processes. Chromatin is organized as a hierarchy from nucleosomes to Mbp chromatin domains (CD) or topologically associating domains (TADs) to higher level compartments culminating in chromosome territories (CT). Microscopic and sequencing techniques have substantiated chromatin organization as a critical factor regulating gene expression. For example, enhancers loop back to interact with their target genes almost exclusively within TADs, distally located coregulated genes reposition into common transcription factories upon activation, and Mbp CDs exhibit dynamic motion and configurational changes in vivo. A longstanding question in the nucleus field is whether an interactive nuclear matrix provides a direct link between structure and function. The findings of nonrandom radial positioning of CT within the nucleus suggest the possibility of preferential interaction patterns among populations of CT. Sequential labeling up to 10 CT followed by application of computer imaging and geometric graph mining algorithms revealed cell-type specific interchromosomal networks (ICN) of CT that are altered during the cell cycle, differentiation, and cancer progression. It is proposed that the ICN correlate with the global level of genome regulation. These approaches also demonstrated that the large scale 3-D topology of CT is specific for each CT. The cell-type specific proximity of certain chromosomal regions in normal cells may explain the propensity of distinct translocations in cancer subtypes. Understanding how genes are dysregulated upon disruption of the normal "wiring" of the nucleus by translocations, deletions, and amplifications that are hallmarks of cancer, should enable more targeted therapeutic strategies.
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Affiliation(s)
- Andrew J Fritz
- Department of Biochemistry and University of Vermont Cancer Center, The University of Vermont Larner College of Medicine, Burlington, Vermont
| | - Nitasha Sehgal
- Department of Biological Sciences, University at Buffalo, Buffalo, New York
| | - Artem Pliss
- Institute for Lasers, Photonics and Biophotonics and the Department of Chemistry, University at Buffalo, Buffalo, New York
| | - Jinhui Xu
- Department of Computer Science and Engineering, University at Buffalo, Buffalo, New York
| | - Ronald Berezney
- Department of Biological Sciences, University at Buffalo, Buffalo, New York
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