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Meschichi A, Rosa S. Plant chromatin on the move: an overview of chromatin mobility during transcription and DNA repair. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:953-962. [PMID: 36811211 DOI: 10.1111/tpj.16159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 02/16/2023] [Accepted: 02/19/2023] [Indexed: 06/18/2023]
Abstract
It has become increasingly clear in recent years that chromosomes are highly dynamic entities. Chromatin mobility and re-arrangement are involved in many biological processes, including gene regulation and the maintenance of genome stability. Despite extensive studies on chromatin mobility in yeast and animal systems, up until recently, not much had been investigated at this level in plants. For plants to achieve proper growth and development, they need to respond rapidly and appropriately to environmental stimuli. Therefore, understanding how chromatin mobility can support plant responses may offer profound insights into the functioning of plant genomes. In this review, we discuss the state of the art related to chromatin mobility in plants, including the available technologies for their role in various cellular processes.
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Affiliation(s)
- Anis Meschichi
- Plant Biology Department, Swedish University of Agricultural Sciences (SLU), Almas Allé 5, Uppsala, Sweden
| | - Stefanie Rosa
- Plant Biology Department, Swedish University of Agricultural Sciences (SLU), Almas Allé 5, Uppsala, Sweden
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2
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Willemin A, Szabó D, Pombo A. Epigenetic regulatory layers in the 3D nucleus. Mol Cell 2024; 84:415-428. [PMID: 38242127 PMCID: PMC10872226 DOI: 10.1016/j.molcel.2023.12.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 11/21/2023] [Accepted: 12/15/2023] [Indexed: 01/21/2024]
Abstract
Nearly 7 decades have elapsed since Francis Crick introduced the central dogma of molecular biology, as part of his ideas on protein synthesis, setting the fundamental rules of sequence information transfer from DNA to RNAs and proteins. We have since learned that gene expression is finely tuned in time and space, due to the activities of RNAs and proteins on regulatory DNA elements, and through cell-type-specific three-dimensional conformations of the genome. Here, we review major advances in genome biology and discuss a set of ideas on gene regulation and highlight how various biomolecular assemblies lead to the formation of structural and regulatory features within the nucleus, with roles in transcriptional control. We conclude by suggesting further developments that will help capture the complex, dynamic, and often spatially restricted events that govern gene expression in mammalian cells.
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Affiliation(s)
- Andréa Willemin
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology (BIMSB), Epigenetic Regulation and Chromatin Architecture Group, Berlin, Germany; Humboldt-Universität zu Berlin, Institute for Biology, Berlin, Germany.
| | - Dominik Szabó
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology (BIMSB), Epigenetic Regulation and Chromatin Architecture Group, Berlin, Germany; Humboldt-Universität zu Berlin, Institute for Biology, Berlin, Germany
| | - Ana Pombo
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology (BIMSB), Epigenetic Regulation and Chromatin Architecture Group, Berlin, Germany; Humboldt-Universität zu Berlin, Institute for Biology, Berlin, Germany.
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3
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Sen S, Dhuppar S, Mazumder A. Combined 3D DNA FISH, Single-Molecule RNA FISH, and Immunofluorescence. Methods Mol Biol 2024; 2784:203-214. [PMID: 38502488 DOI: 10.1007/978-1-0716-3766-1_14] [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] [Indexed: 03/21/2024]
Abstract
Nuclear architecture is a potential regulator of gene expression in eukaryotic cells. Studies connecting nuclear architecture to gene expression are often population-averaged and do not report on the cell-level heterogeneity in genome organization and associated gene expression. In this report we present a simple way to combine fluorescence in situ hybridization (FISH)-based detection of DNA, with single-molecule RNA FISH (smFISH) and immunofluorescence (IF), while also preserving the three-dimensional (3D) nuclear architecture of a cell. Recently developed smFISH techniques enable the detection of individual RNA molecules; while using 3D DNA FISH, copy numbers and positions of genes inside the nucleus can be interrogated without interfering with 3D nuclear architecture. Our method to combine 3D DNA FISH with smFISH and IF enables a unique quantitative handle on the central dogma of molecular biology.
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Affiliation(s)
- Souvik Sen
- Tata Institute of Fundamental Research Hyderabad, Hyderabad, Telangana, India
| | - Shivnarayan Dhuppar
- Tata Institute of Fundamental Research Hyderabad, Hyderabad, Telangana, India
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Aprotim Mazumder
- Tata Institute of Fundamental Research Hyderabad, Hyderabad, Telangana, India.
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4
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Labade AS, Salvi A, Kar S, Karmodiya K, Sengupta K. Nup93 and CTCF modulate spatiotemporal dynamics and function of the HOXA gene locus during differentiation. J Cell Sci 2021; 134:273378. [PMID: 34746948 DOI: 10.1242/jcs.259307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 10/30/2021] [Indexed: 11/20/2022] Open
Abstract
Nucleoporins regulate nuclear transport and are also involved in DNA damage, repair, cell cycle, chromatin organization, and gene expression. Here, we studied the role of nucleoporin Nup93 and the chromatin organizer CTCF in regulating HOXA expression during differentiation. ChIP sequencing revealed a significant overlap between Nup93 and CTCF peaks. Interestingly, Nup93 and CTCF are associated with the 3' and 5'HOXA genes respectively. Depletions of Nup93 and CTCF antagonistically modulate expression levels of 3'and 5'HOXA genes in undifferentiated NT2/D1 cells. Nup93 also regulates the localization of the HOXA gene locus, which disengages from the nuclear periphery upon Nup93 but not CTCF depletion, consistent with its upregulation. The dynamic association of Nup93 and CTCF with the HOXA locus during differentiation correlates with its spatial positioning and expression. While Nup93 tethers the HOXA locus to the nuclear periphery, CTCF potentially regulates looping of the HOXA gene cluster in a temporal manner. In summary, Nup93 and CTCF complement one another in modulating the spatiotemporal dynamics and function of the HOXA gene locus during differentiation.
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Affiliation(s)
- Ajay S Labade
- Department of Biology, Indian Institute of Science Education and Research (IISER), Pune 411008 Maharashtra, INDIA
| | - Adwait Salvi
- Department of Biology, Indian Institute of Science Education and Research (IISER), Pune 411008 Maharashtra, INDIA
| | - Saswati Kar
- Department of Biology, Indian Institute of Science Education and Research (IISER), Pune 411008 Maharashtra, INDIA
| | - Krishanpal Karmodiya
- Department of Biology, Indian Institute of Science Education and Research (IISER), Pune 411008 Maharashtra, INDIA
| | - Kundan Sengupta
- Department of Biology, Indian Institute of Science Education and Research (IISER), Pune 411008 Maharashtra, INDIA
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5
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Sobreira DR, Joslin AC, Zhang Q, Williamson I, Hansen GT, Farris KM, Sakabe NJ, Sinnott-Armstrong N, Bozek G, Jensen-Cody SO, Flippo KH, Ober C, Bickmore WA, Potthoff M, Chen M, Claussnitzer M, Aneas I, Nóbrega MA. Extensive pleiotropism and allelic heterogeneity mediate metabolic effects of IRX3 and IRX5. Science 2021; 372:1085-1091. [PMID: 34083488 PMCID: PMC8386003 DOI: 10.1126/science.abf1008] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 04/28/2021] [Indexed: 12/11/2022]
Abstract
Whereas coding variants often have pleiotropic effects across multiple tissues, noncoding variants are thought to mediate their phenotypic effects by specific tissue and temporal regulation of gene expression. Here, we investigated the genetic and functional architecture of a genomic region within the FTO gene that is strongly associated with obesity risk. We show that multiple variants on a common haplotype modify the regulatory properties of several enhancers targeting IRX3 and IRX5 from megabase distances. We demonstrate that these enhancers affect gene expression in multiple tissues, including adipose and brain, and impart regulatory effects during a restricted temporal window. Our data indicate that the genetic architecture of disease-associated loci may involve extensive pleiotropy, allelic heterogeneity, shared allelic effects across tissues, and temporally restricted effects.
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Affiliation(s)
- Débora R Sobreira
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA.
| | - Amelia C Joslin
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Qi Zhang
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
- Section of Genetic Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Iain Williamson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Grace T Hansen
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Kathryn M Farris
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Noboru J Sakabe
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Nasa Sinnott-Armstrong
- Department of Genetics, Stanford University, Stanford 94305 CA, USA
- Metabolism Program and Cardiovascular Disease Initiative, Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, MA 02142, USA
| | - Grazyna Bozek
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Sharon O Jensen-Cody
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Kyle H Flippo
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Carole Ober
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Wendy A Bickmore
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Matthew Potthoff
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Mengjie Chen
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA
- Section of Genetic Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Melina Claussnitzer
- Metabolism Program and Cardiovascular Disease Initiative, Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, MA 02142, USA
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02131, USA
| | - Ivy Aneas
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA.
| | - Marcelo A Nóbrega
- Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA.
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6
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Ushiki A, Zhang Y, Xiong C, Zhao J, Georgakopoulos-Soares I, Kane L, Jamieson K, Bamshad MJ, Nickerson DA, Shen Y, Lettice LA, Silveira-Lucas EL, Petit F, Ahituv N. Deletion of CTCF sites in the SHH locus alters enhancer-promoter interactions and leads to acheiropodia. Nat Commun 2021; 12:2282. [PMID: 33863876 PMCID: PMC8052326 DOI: 10.1038/s41467-021-22470-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 03/12/2021] [Indexed: 12/18/2022] Open
Abstract
Acheiropodia, congenital limb truncation, is associated with homozygous deletions in the LMBR1 gene around ZRS, an enhancer regulating SHH during limb development. How these deletions lead to this phenotype is unknown. Using whole-genome sequencing, we fine-mapped the acheiropodia-associated region to 12 kb and show that it does not function as an enhancer. CTCF and RAD21 ChIP-seq together with 4C-seq and DNA FISH identify three CTCF sites within the acheiropodia-deleted region that mediate the interaction between the ZRS and the SHH promoter. This interaction is substituted with other CTCF sites centromeric to the ZRS in the disease state. Mouse knockouts of the orthologous 12 kb sequence have no apparent abnormalities, showcasing the challenges in modelling CTCF alterations in animal models due to inherent motif differences between species. Our results show that alterations in CTCF motifs can lead to a Mendelian condition due to altered enhancer-promoter interactions.
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Affiliation(s)
- Aki Ushiki
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Yichi Zhang
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Chenling Xiong
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Jingjing Zhao
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Ilias Georgakopoulos-Soares
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Lauren Kane
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Kirsty Jamieson
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Michael J Bamshad
- Department of Pediatrics, University of Washington, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Brotman-Baty Institute, Seattle, WA, USA
| | - Deborah A Nickerson
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Brotman-Baty Institute, Seattle, WA, USA
| | - Yin Shen
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA
| | - Laura A Lettice
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | | | - Florence Petit
- CHU Lille, University of Lille, EA7364 RADEME, Lille, France
| | - Nadav Ahituv
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA.
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA.
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7
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Abstract
In the past several decades, the establishment of in vitro models of pluripotency has ushered in a golden era for developmental and stem cell biology. Research in this arena has led to profound insights into the regulatory features that shape early embryonic development. Nevertheless, an integrative theory of the epigenetic principles that govern the pluripotent nucleus remains elusive. Here, we summarize the epigenetic characteristics that define the pluripotent state. We cover what is currently known about the epigenome of pluripotent stem cells and reflect on the use of embryonic stem cells as an experimental system. In addition, we highlight insights from super-resolution microscopy, which have advanced our understanding of the form and function of chromatin, particularly its role in establishing the characteristically "open chromatin" of pluripotent nuclei. Further, we discuss the rapid improvements in 3C-based methods, which have given us a means to investigate the 3D spatial organization of the pluripotent genome. This has aided the adaptation of prior notions of a "pluripotent molecular circuitry" into a more holistic model, where hotspots of co-interacting domains correspond with the accumulation of pluripotency-associated factors. Finally, we relate these earlier hypotheses to an emerging model of phase separation, which posits that a biophysical mechanism may presuppose the formation of a pluripotent-state-defining transcriptional program.
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Affiliation(s)
| | - Eran Meshorer
- Department of Genetics, the Institute of Life Sciences
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel 9190400
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8
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Dhuppar S, Mazumder A. Investigating cell cycle-dependent gene expression in the context of nuclear architecture at single-allele resolution. J Cell Sci 2020; 133:jcs246330. [PMID: 32467328 DOI: 10.1242/jcs.246330] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/10/2020] [Indexed: 12/20/2022] Open
Abstract
Nuclear architecture is the organization of the genome within a cell nucleus with respect to different nuclear landmarks such as the nuclear lamina, nuclear matrix or nucleoli. Recently, nuclear architecture has emerged as a major regulator of gene expression in mammalian cells. However, studies connecting nuclear architecture with gene expression are largely population-averaged and do not report on the heterogeneity in genome organization or gene expression within a population. In this report we present a method for combining 3D DNA fluorescence in situ hybridization (FISH) with single-molecule RNA FISH (smFISH) and immunofluorescence to study nuclear architecture-dependent gene regulation on a cell-by-cell basis. We further combine our method with imaging-based cell cycle staging to correlate nuclear architecture with gene expression across the cell cycle. We present this in the context of the cyclin-A2 (CCNA2) gene, which has known cell cycle-dependent expression. We show that, across the cell cycle, the expression of a CCNA2 gene copy is stochastic and depends neither on its sub-nuclear position - which usually lies close to nuclear lamina - nor on the expression from other copies of the gene.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Shivnarayan Dhuppar
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally, Serlingampally Mandal, Hyderabad 500046, Telangana, India
| | - Aprotim Mazumder
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally, Serlingampally Mandal, Hyderabad 500046, Telangana, India
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9
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Boyle S, Flyamer IM, Williamson I, Sengupta D, Bickmore WA, Illingworth RS. A central role for canonical PRC1 in shaping the 3D nuclear landscape. Genes Dev 2020; 34:931-949. [PMID: 32439634 PMCID: PMC7328521 DOI: 10.1101/gad.336487.120] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 04/13/2020] [Indexed: 02/04/2023]
Abstract
In this study from Boyle et al., the authors investigated the role of Polycomb-repressive complex 1 (PRC1) in shaping 3D genome organization in mouse embryonic stem cells. Using a combination of imaging and Hi-C analyses they show that PRC1-mediated long-range interactions are independent of CTCF and can bridge sites at a megabase scale, thus providing novel insights into the function of PRC1. Polycomb group (PcG) proteins silence gene expression by chemically and physically modifying chromatin. A subset of PcG target loci are compacted and cluster in the nucleus; a conformation that is thought to contribute to gene silencing. However, how these interactions influence gross nuclear organization and their relationship with transcription remains poorly understood. Here we examine the role of Polycomb-repressive complex 1 (PRC1) in shaping 3D genome organization in mouse embryonic stem cells (mESCs). Using a combination of imaging and Hi-C analyses, we show that PRC1-mediated long-range interactions are independent of CTCF and can bridge sites at a megabase scale. Impairment of PRC1 enzymatic activity does not directly disrupt these interactions. We demonstrate that PcG targets coalesce in vivo, and that developmentally induced expression of one of the target loci disrupts this spatial arrangement. Finally, we show that transcriptional activation and the loss of PRC1-mediated interactions are separable events. These findings provide important insights into the function of PRC1, while highlighting the complexity of this regulatory system.
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Affiliation(s)
- Shelagh Boyle
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Ilya M Flyamer
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Iain Williamson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Dipta Sengupta
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Wendy A Bickmore
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Robert S Illingworth
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
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10
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Ruiz Y, Ramos PL, Soto J, Rodríguez M, Carlos N, Reyes A, Callard D, Sánchez Y, Pujol M, Fuentes A. The M4 insulator, the TM2 matrix attachment region, and the double copy of the heavy chain gene contribute to the enhanced accumulation of the PHB-01 antibody in tobacco plants. Transgenic Res 2020; 29:171-186. [PMID: 31919795 DOI: 10.1007/s11248-019-00187-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 12/31/2019] [Indexed: 11/24/2022]
Abstract
The expression of recombinant proteins in plants is a valuable alternative to bioreactors using mammalian cell systems. Ease of scaling, and their inability to host human pathogens, enhance the use of plants to generate complex therapeutic products such as monoclonal antibodies. However, stably transformed plants expressing antibodies normally have a poor accumulation of these proteins that probably arise from the negative positional effects of their flanking chromatin. The induction of boundaries between the transgenes and the surrounding DNA using matrix attachment regions (MAR) and insulator elements may minimize these effects. With the PHB-01 antibody as a model, we demonstrated that the insertion of DNA elements, the TM2 (MAR) and M4 insulator, flanking the transcriptional cassettes that encode the light and heavy chains of the PHB-01 antibody, increased the protein accumulation that remained stable in the first plant progeny. The M4 insulator had a stronger effect than the TM2, with over a twofold increase compared to the standard construction. This effect was probably associated with an enhancer-promoter interference. Moreover, transgenic plants harboring two transcriptional units encoding for the PHB-01 heavy chain combined with both TM2 and M4 elements enhanced the accumulation of the antibody. In summary, the M4 combined with a double transcriptional unit of the heavy chain may be a suitable strategy for potentiating PHB-01 production in tobacco plants.
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Affiliation(s)
- Yoslaine Ruiz
- Plant Biotechnology Department, Center for Genetic Engineering and Biotechnology, Cuba, Ave. 31/158 and 190, Playa, P.O. Box 6162, 10600, Havana, Cuba.
| | - Pedro Luis Ramos
- Plant Biotechnology Department, Center for Genetic Engineering and Biotechnology, Cuba, Ave. 31/158 and 190, Playa, P.O. Box 6162, 10600, Havana, Cuba
- Department of Phytopathology and Plant Biochemistry, Instituto Biologico, São Paulo, Brazil
| | - Jeny Soto
- Plant Biotechnology Department, Center for Genetic Engineering and Biotechnology, Cuba, Ave. 31/158 and 190, Playa, P.O. Box 6162, 10600, Havana, Cuba
- Comparative Pathology Department, University of Miami, Miami, USA
| | - Meilyn Rodríguez
- Plant Biotechnology Department, Center for Genetic Engineering and Biotechnology, Cuba, Ave. 31/158 and 190, Playa, P.O. Box 6162, 10600, Havana, Cuba
| | - Natacha Carlos
- Plant Biotechnology Department, Center for Genetic Engineering and Biotechnology, Cuba, Ave. 31/158 and 190, Playa, P.O. Box 6162, 10600, Havana, Cuba
| | - Aneisi Reyes
- Plant Biotechnology Department, Center for Genetic Engineering and Biotechnology, Cuba, Ave. 31/158 and 190, Playa, P.O. Box 6162, 10600, Havana, Cuba
| | - Danay Callard
- Plant Biotechnology Department, Center for Genetic Engineering and Biotechnology, Cuba, Ave. 31/158 and 190, Playa, P.O. Box 6162, 10600, Havana, Cuba
| | - Yadira Sánchez
- Plant Biotechnology Department, Center for Genetic Engineering and Biotechnology, Cuba, Ave. 31/158 and 190, Playa, P.O. Box 6162, 10600, Havana, Cuba
| | - Merardo Pujol
- Plant Biotechnology Department, Center for Genetic Engineering and Biotechnology, Cuba, Ave. 31/158 and 190, Playa, P.O. Box 6162, 10600, Havana, Cuba
| | - Alejandro Fuentes
- Plant Biotechnology Department, Center for Genetic Engineering and Biotechnology, Cuba, Ave. 31/158 and 190, Playa, P.O. Box 6162, 10600, Havana, Cuba.
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11
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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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12
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Finn EH, Misteli T. Molecular basis and biological function of variability in spatial genome organization. Science 2019; 365:365/6457/eaaw9498. [PMID: 31488662 DOI: 10.1126/science.aaw9498] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 07/22/2019] [Indexed: 12/14/2022]
Abstract
The complex three-dimensional organization of genomes in the cell nucleus arises from a wide range of architectural features including DNA loops, chromatin domains, and higher-order compartments. Although these features are universally present in most cell types and tissues, recent single-cell biochemistry and imaging approaches have demonstrated stochasticity in transcription and high variability of chromatin architecture in individual cells. We review the occurrence, mechanistic basis, and functional implications of stochasticity in genome organization. We summarize recent observations on cell- and allele-specific variability of genome architecture, discuss the nature of extrinsic and intrinsic sources of variability in genome organization, and highlight potential implications of structural heterogeneity for genome function.
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Affiliation(s)
| | - Tom Misteli
- National Cancer Institute, Bethesda, MD 20892, USA.
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13
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McLaughlin K, Flyamer IM, Thomson JP, Mjoseng HK, Shukla R, Williamson I, Grimes GR, Illingworth RS, Adams IR, Pennings S, Meehan RR, Bickmore WA. DNA Methylation Directs Polycomb-Dependent 3D Genome Re-organization in Naive Pluripotency. Cell Rep 2019; 29:1974-1985.e6. [PMID: 31722211 PMCID: PMC6856714 DOI: 10.1016/j.celrep.2019.10.031] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 09/09/2019] [Accepted: 10/09/2019] [Indexed: 11/14/2022] Open
Abstract
The DNA hypomethylation that occurs when embryonic stem cells (ESCs) are directed to the ground state of naive pluripotency by culturing in two small molecule inhibitors (2i) results in redistribution of polycomb (H3K27me3) away from its target loci. Here, we demonstrate that 3D genome organization is also altered in 2i, with chromatin decompaction at polycomb target loci and a loss of long-range polycomb interactions. By preventing DNA hypomethylation during the transition to the ground state, we are able to restore to ESC in 2i the H3K27me3 distribution, as well as polycomb-mediated 3D genome organization that is characteristic of primed ESCs grown in serum. However, these cells retain the functional characteristics of 2i ground-state ESCs. Our findings demonstrate the central role of DNA methylation in shaping major aspects of 3D genome organization but caution against assuming causal roles for the epigenome and 3D genome in gene regulation and function in ESCs.
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Affiliation(s)
- Katy McLaughlin
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh EH4 2XU, UK
| | - Ilya M Flyamer
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh EH4 2XU, UK
| | - John P Thomson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh EH4 2XU, UK
| | - Heidi K Mjoseng
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh EH4 2XU, UK
| | - Ruchi Shukla
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh EH4 2XU, UK; Northern Institute for Cancer Research, Framlington Place, Medical Faculty, Newcastle upon Tyne NE2 4HH, UK
| | - Iain Williamson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh EH4 2XU, UK
| | - Graeme R Grimes
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh EH4 2XU, UK
| | - Robert S Illingworth
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh EH4 2XU, UK
| | - Ian R Adams
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh EH4 2XU, UK
| | - Sari Pennings
- Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Richard R Meehan
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh EH4 2XU, UK.
| | - Wendy A Bickmore
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh EH4 2XU, UK.
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14
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Williamson I, Kane L, Devenney PS, Flyamer IM, Anderson E, Kilanowski F, Hill RE, Bickmore WA, Lettice LA. Developmentally regulated Shh expression is robust to TAD perturbations. Development 2019; 146:dev179523. [PMID: 31511252 PMCID: PMC7212092 DOI: 10.1242/dev.179523] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 09/02/2019] [Indexed: 12/26/2022]
Abstract
Topologically associating domains (TADs) have been proposed to both guide and constrain enhancer activity. Shh is located within a TAD known to contain all its enhancers. To investigate the importance of chromatin conformation and TAD integrity on developmental gene regulation, we have manipulated the Shh TAD - creating internal deletions, deleting CTCF sites, and deleting and inverting sequences at TAD boundaries. Chromosome conformation capture and fluorescence in situ hybridisation assays were used to investigate the changes in chromatin conformation that result from these manipulations. Our data suggest that these substantial alterations in TAD structure have no readily detectable effect on Shh expression patterns or levels of Shh expression during development - except where enhancers are deleted - and result in no detectable phenotypes. Only in the case of a larger deletion at one TAD boundary could ectopic influence of the Shh limb enhancer be detected on a gene (Mnx1) in the neighbouring TAD. Our data suggests that, contrary to expectations, the developmental regulation of Shh expression is remarkably robust to TAD perturbations.
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Affiliation(s)
- Iain Williamson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Lauren Kane
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Paul S Devenney
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Ilya M Flyamer
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Eve Anderson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Fiona Kilanowski
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Robert E Hill
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Wendy A Bickmore
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Laura A Lettice
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh, EH4 2XU, UK
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15
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Benabdallah NS, Williamson I, Illingworth RS, Kane L, Boyle S, Sengupta D, Grimes GR, Therizols P, Bickmore WA. Decreased Enhancer-Promoter Proximity Accompanying Enhancer Activation. Mol Cell 2019; 76:473-484.e7. [PMID: 31494034 PMCID: PMC6838673 DOI: 10.1016/j.molcel.2019.07.038] [Citation(s) in RCA: 224] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 05/08/2019] [Accepted: 07/29/2019] [Indexed: 12/29/2022]
Abstract
Enhancers can regulate the promoters of their target genes over very large genomic distances. It is widely assumed that mechanisms of enhancer action involve the reorganization of three-dimensional chromatin architecture, but this is poorly understood. The predominant model involves physical enhancer-promoter interaction by looping out the intervening chromatin. However, studying the enhancer-driven activation of the Sonic hedgehog gene (Shh), we have identified a change in chromosome conformation that is incompatible with this simple looping model. Using super-resolution 3D-FISH and chromosome conformation capture, we observe a decreased spatial proximity between Shh and its enhancers during the differentiation of embryonic stem cells to neural progenitors. We show that this can be recapitulated by synthetic enhancer activation, is impeded by chromatin-bound proteins located between the enhancer and the promoter, and appears to involve the catalytic activity of poly (ADP-ribose) polymerase. Our data suggest that models of enhancer-promoter communication need to encompass chromatin conformations other than looping. Super-resolution microscopy reveals increased enhancer-promoter separation upon activation Synthetic enhancer activation supports decreased enhancer-promoter proximity Enhancer-promoter separation can be driven by poly(ADP-ribose) polymerase 1
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Affiliation(s)
- Nezha S Benabdallah
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK; Edinburgh Super Resolution Imaging Consortium (ESRIC), Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Iain Williamson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Robert S Illingworth
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Lauren Kane
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Shelagh Boyle
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Dipta Sengupta
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Graeme R Grimes
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Pierre Therizols
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK; UMR INSERM 944, CNRS 7212, Bâtiment Jean Bernard, Hôpital Saint Louis, Paris, France
| | - Wendy A Bickmore
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK.
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16
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A subset of topologically associating domains fold into mesoscale core-periphery networks. Sci Rep 2019; 9:9526. [PMID: 31266973 PMCID: PMC6606598 DOI: 10.1038/s41598-019-45457-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 06/07/2019] [Indexed: 12/21/2022] Open
Abstract
Mammalian genomes are folded into a hierarchy of compartments, topologically associating domains (TADs), subTADs, and long-range looping interactions. The higher-order folding patterns of chromatin contacts within TADs and how they localize to disease-associated single nucleotide variants (daSNVs) remains an open area of investigation. Here, we analyze high-resolution Hi-C data with graph theory to understand possible mesoscale network architecture within chromatin domains. We identify a subset of TADs exhibiting strong core-periphery mesoscale structure in embryonic stem cells, neural progenitor cells, and cortical neurons. Hyper-connected core nodes co-localize with genomic segments engaged in multiple looping interactions and enriched for occupancy of the architectural protein CCCTC binding protein (CTCF). CTCF knockdown and in silico deletion of CTCF-bound core nodes disrupts core-periphery structure, whereas in silico mutation of cell type-specific enhancer or gene nodes has a negligible effect. Importantly, neuropsychiatric daSNVs are significantly more likely to localize with TADs folded into core-periphery networks compared to domains devoid of such structure. Together, our results reveal that a subset of TADs encompasses looping interactions connected into a core-periphery mesoscale network. We hypothesize that daSNVs in the periphery of genome folding networks might preserve global nuclear architecture but cause local topological and functional disruptions contributing to human disease. By contrast, daSNVs co-localized with hyper-connected core nodes might cause severe topological and functional disruptions. Overall, these findings shed new light into the mesoscale network structure of fine scale genome folding within chromatin domains and its link to common genetic variants in human disease.
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17
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Zheng H, Xie W. The role of 3D genome organization in development and cell differentiation. Nat Rev Mol Cell Biol 2019; 20:535-550. [DOI: 10.1038/s41580-019-0132-4] [Citation(s) in RCA: 282] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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18
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Nolte C, De Kumar B, Krumlauf R. Hox genes: Downstream "effectors" of retinoic acid signaling in vertebrate embryogenesis. Genesis 2019; 57:e23306. [PMID: 31111645 DOI: 10.1002/dvg.23306] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 05/09/2019] [Accepted: 05/10/2019] [Indexed: 12/31/2022]
Abstract
One of the major regulatory challenges of animal development is to precisely coordinate in space and time the formation, specification, and patterning of cells that underlie elaboration of the basic body plan. How does the vertebrate plan for the nervous and hematopoietic systems, heart, limbs, digestive, and reproductive organs derive from seemingly similar population of cells? These systems are initially established and patterned along the anteroposterior axis (AP) by opposing signaling gradients that lead to the activation of gene regulatory networks involved in axial specification, including the Hox genes. The retinoid signaling pathway is one of the key signaling gradients coupled to the establishment of axial patterning. The nested domains of Hox gene expression, which provide a combinatorial code for axial patterning, arise in part through a differential response to retinoic acid (RA) diffusing from anabolic centers established within the embryo during development. Hence, Hox genes are important direct effectors of retinoid signaling in embryogenesis. This review focuses on describing current knowledge on the complex mechanisms and regulatory processes, which govern the response of Hox genes to RA in several tissue contexts including the nervous system during vertebrate development.
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Affiliation(s)
- Christof Nolte
- Stowers Institute for Medical Research, Kansas City, Missouri
| | - Bony De Kumar
- Stowers Institute for Medical Research, Kansas City, Missouri
| | - Robb Krumlauf
- Stowers Institute for Medical Research, Kansas City, Missouri.,Department of Anatomy and Cell Biology, Kansas University Medical Center, Kansas City, Kansas
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19
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Finn EH, Pegoraro G, Brandão HB, Valton AL, Oomen ME, Dekker J, Mirny L, Misteli T. Extensive Heterogeneity and Intrinsic Variation in Spatial Genome Organization. Cell 2019; 176:1502-1515.e10. [PMID: 30799036 DOI: 10.1016/j.cell.2019.01.020] [Citation(s) in RCA: 314] [Impact Index Per Article: 52.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 10/18/2018] [Accepted: 01/09/2019] [Indexed: 01/16/2023]
Abstract
Several general principles of global 3D genome organization have recently been established, including non-random positioning of chromosomes and genes in the cell nucleus, distinct chromatin compartments, and topologically associating domains (TADs). However, the extent and nature of cell-to-cell and cell-intrinsic variability in genome architecture are still poorly characterized. Here, we systematically probe heterogeneity in genome organization. High-throughput optical mapping of several hundred intra-chromosomal interactions in individual human fibroblasts demonstrates low association frequencies, which are determined by genomic distance, higher-order chromatin architecture, and chromatin environment. The structure of TADs is variable between individual cells, and inter-TAD associations are common. Furthermore, single-cell analysis reveals independent behavior of individual alleles in single nuclei. Our observations reveal extensive variability and heterogeneity in genome organization at the level of individual alleles and demonstrate the coexistence of a broad spectrum of genome configurations in a cell population.
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Affiliation(s)
| | - Gianluca Pegoraro
- High-throughput Imaging Facility, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Hugo B Brandão
- Graduate Program in Biophysics, Harvard University, Cambridge, MA 02138, USA
| | - Anne-Laure Valton
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Marlies E Oomen
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Job Dekker
- Howard Hughes Medical Institute, Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Leonid Mirny
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Tom Misteli
- National Cancer Institute, NIH, Bethesda, MD 20892, USA.
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20
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Szalaj P, Plewczynski D. Three-dimensional organization and dynamics of the genome. Cell Biol Toxicol 2018; 34:381-404. [PMID: 29568981 PMCID: PMC6133016 DOI: 10.1007/s10565-018-9428-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/11/2018] [Indexed: 12/30/2022]
Abstract
Genome is a complex hierarchical structure, and its spatial organization plays an important role in its function. Chromatin loops and topological domains form the basic structural units of this multiscale organization and are essential to orchestrate complex regulatory networks and transcription mechanisms. They also form higher-order structures such as chromosomal compartments and chromosome territories. Each level of this intrinsic architecture is governed by principles and mechanisms that we only start to understand. In this review, we summarize the current view of the genome architecture on the scales ranging from chromatin loops to the whole genome. We describe cell-to-cell variability, links between genome reorganization and various genomic processes, such as chromosome X inactivation and cell differentiation, and the interplay between different experimental techniques.
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Affiliation(s)
- Przemyslaw Szalaj
- Centre for Innovative Research, Medical University of Bialystok, Białystok, Poland.
- I-BioStat, Hasselt University, Hasselt, Belgium.
- Centre of New Technologies, University of Warsaw, Warsaw, Poland.
| | - Dariusz Plewczynski
- Centre for Innovative Research, Medical University of Bialystok, Białystok, Poland
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Mathematics and Information Science, Warsaw University of Technology, Warsaw, Poland
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21
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Brown JM, Roberts NA, Graham B, Waithe D, Lagerholm C, Telenius JM, De Ornellas S, Oudelaar AM, Scott C, Szczerbal I, Babbs C, Kassouf MT, Hughes JR, Higgs DR, Buckle VJ. A tissue-specific self-interacting chromatin domain forms independently of enhancer-promoter interactions. Nat Commun 2018; 9:3849. [PMID: 30242161 PMCID: PMC6155075 DOI: 10.1038/s41467-018-06248-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 08/24/2018] [Indexed: 11/08/2022] Open
Abstract
Self-interacting chromatin domains encompass genes and their cis-regulatory elements; however, the three-dimensional form a domain takes, whether this relies on enhancer-promoter interactions, and the processes necessary to mediate the formation and maintenance of such domains, remain unclear. To examine these questions, here we use a combination of high-resolution chromosome conformation capture, a non-denaturing form of fluorescence in situ hybridisation and super-resolution imaging to study a 70 kb domain encompassing the mouse α-globin regulatory locus. We show that this region forms an erythroid-specific, decompacted, self-interacting domain, delimited by frequently apposed CTCF/cohesin binding sites early in terminal erythroid differentiation, and does not require transcriptional elongation for maintenance of the domain structure. Formation of this domain does not rely on interactions between the α-globin genes and their major enhancers, suggesting a transcription-independent mechanism for establishment of the domain. However, absence of the major enhancers does alter internal domain interactions. Formation of a loop domain therefore appears to be a mechanistic process that occurs irrespective of the specific interactions within.
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Affiliation(s)
- Jill M Brown
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Nigel A Roberts
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Bryony Graham
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Dominic Waithe
- Wolfson Imaging Centre Oxford, MRC Weatherall Institute of Molecular Medicine, Oxford, OX3 9DS, UK
| | - Christoffer Lagerholm
- Wolfson Imaging Centre Oxford, MRC Weatherall Institute of Molecular Medicine, Oxford, OX3 9DS, UK
| | - Jelena M Telenius
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Sara De Ornellas
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - A Marieke Oudelaar
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Caroline Scott
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Izabela Szczerbal
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
- Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Wolynska 33, 60-637 Poznan, Poland
| | - Christian Babbs
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Mira T Kassouf
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Jim R Hughes
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Douglas R Higgs
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Veronica J Buckle
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK.
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22
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Dultz E, Mancini R, Polles G, Vallotton P, Alber F, Weis K. Quantitative imaging of chromatin decompaction in living cells. Mol Biol Cell 2018; 29:1763-1777. [PMID: 29771637 DOI: 10.1101/219253] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
Chromatin organization is highly dynamic and regulates transcription. Upon transcriptional activation, chromatin is remodeled and referred to as "open," but quantitative and dynamic data of this decompaction process are lacking. Here, we have developed a quantitative high resolution-microscopy assay in living yeast cells to visualize and quantify chromatin dynamics using the GAL7-10-1 locus as a model system. Upon transcriptional activation of these three clustered genes, we detect an increase of the mean distance across this locus by >100 nm. This decompaction is linked to active transcription but is not sensitive to the histone deacetylase inhibitor trichostatin A or to deletion of the histone acetyl transferase Gcn5. In contrast, the deletion of SNF2 (encoding the ATPase of the SWI/SNF chromatin remodeling complex) or the deactivation of the histone chaperone complex FACT lead to a strongly reduced decompaction without significant effects on transcriptional induction in FACT mutants. Our findings are consistent with nucleosome remodeling and eviction activities being major contributors to chromatin reorganization during transcription but also suggest that transcription can occur in the absence of detectable decompaction.
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Affiliation(s)
- Elisa Dultz
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Roberta Mancini
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Guido Polles
- Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089
| | - Pascal Vallotton
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Frank Alber
- Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089
| | - Karsten Weis
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
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23
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Dultz E, Mancini R, Polles G, Vallotton P, Alber F, Weis K. Quantitative imaging of chromatin decompaction in living cells. Mol Biol Cell 2018; 29:1763-1777. [PMID: 29771637 PMCID: PMC6080713 DOI: 10.1091/mbc.e17-11-0648] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Chromatin organization is highly dynamic and regulates transcription. Upon transcriptional activation, chromatin is remodeled and referred to as “open,” but quantitative and dynamic data of this decompaction process are lacking. Here, we have developed a quantitative high resolution–microscopy assay in living yeast cells to visualize and quantify chromatin dynamics using the GAL7-10-1 locus as a model system. Upon transcriptional activation of these three clustered genes, we detect an increase of the mean distance across this locus by >100 nm. This decompaction is linked to active transcription but is not sensitive to the histone deacetylase inhibitor trichostatin A or to deletion of the histone acetyl transferase Gcn5. In contrast, the deletion of SNF2 (encoding the ATPase of the SWI/SNF chromatin remodeling complex) or the deactivation of the histone chaperone complex FACT lead to a strongly reduced decompaction without significant effects on transcriptional induction in FACT mutants. Our findings are consistent with nucleosome remodeling and eviction activities being major contributors to chromatin reorganization during transcription but also suggest that transcription can occur in the absence of detectable decompaction.
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Affiliation(s)
- Elisa Dultz
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Roberta Mancini
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Guido Polles
- Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089
| | - Pascal Vallotton
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Frank Alber
- Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089
| | - Karsten Weis
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
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24
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Rodríguez-Carballo E, Lopez-Delisle L, Zhan Y, Fabre PJ, Beccari L, El-Idrissi I, Huynh THN, Ozadam H, Dekker J, Duboule D. The HoxD cluster is a dynamic and resilient TAD boundary controlling the segregation of antagonistic regulatory landscapes. Genes Dev 2017; 31:2264-2281. [PMID: 29273679 PMCID: PMC5769770 DOI: 10.1101/gad.307769.117] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 11/21/2017] [Indexed: 12/11/2022]
Abstract
The mammalian HoxD cluster lies between two topologically associating domains (TADs) matching distinct enhancer-rich regulatory landscapes. During limb development, the telomeric TAD controls the early transcription of Hoxd genes in forearm cells, whereas the centromeric TAD subsequently regulates more posterior Hoxd genes in digit cells. Therefore, the TAD boundary prevents the terminal Hoxd13 gene from responding to forearm enhancers, thereby allowing proper limb patterning. To assess the nature and function of this CTCF-rich DNA region in embryos, we compared chromatin interaction profiles between proximal and distal limb bud cells isolated from mutant stocks where various parts of this boundary region were removed. The resulting progressive release in boundary effect triggered inter-TAD contacts, favored by the activity of the newly accessed enhancers. However, the boundary was highly resilient, and only a 400-kb deletion, including the whole-gene cluster, was eventually able to merge the neighboring TADs into a single structure. In this unified TAD, both proximal and distal limb enhancers nevertheless continued to work independently over a targeted transgenic reporter construct. We propose that the whole HoxD cluster is a dynamic TAD border and that the exact boundary position varies depending on both the transcriptional status and the developmental context.
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Affiliation(s)
| | - Lucille Lopez-Delisle
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Ye Zhan
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Pierre J Fabre
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Leonardo Beccari
- Department of Genetics and Evolution, University of Geneva, 1205 Geneva, Switzerland
| | - Imane El-Idrissi
- Department of Genetics and Evolution, University of Geneva, 1205 Geneva, Switzerland
| | - Thi Hanh Nguyen Huynh
- Department of Genetics and Evolution, University of Geneva, 1205 Geneva, Switzerland
| | - Hakan Ozadam
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Denis Duboule
- Department of Genetics and Evolution, University of Geneva, 1205 Geneva, Switzerland
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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25
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Wang XQD, Dostie J. Reciprocal regulation of chromatin state and architecture by HOTAIRM1 contributes to temporal collinear HOXA gene activation. Nucleic Acids Res 2017; 45:1091-1104. [PMID: 28180285 PMCID: PMC5388432 DOI: 10.1093/nar/gkw966] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 10/05/2016] [Accepted: 10/22/2016] [Indexed: 12/19/2022] Open
Abstract
Thousands of long non-coding RNAs (lncRNAs) have been identified in mammals, many of which represent important regulators of gene expression. However, the mechanisms used by lncRNAs to control transcription remain largely uncharacterized. Here, we report on HOTAIRM1, a promising lncRNA biomarker in leukemia and solid tumors. We find that HOTAIRM1 contributes to three-dimensional chromatin organization changes required for the temporal collinear activation of HOXA genes. We show that distinct HOTAIRM1 variants preferentially associate with either UTX/MLL or PRC2 complexes to modulate the levels of activating and silencing marks at the bivalent domain. HOTAIRM1 contributes to physical dissociation of chromatin loops at the cluster proximal end, which delays recruitment of the histone demethylase UTX and transcription of central HOXA genes. Interestingly, we find overall proximal HOXA gene activation without chromatin conformation changes by HOTAIRM1 in a different cell type. Our results reveal a previously unappreciated relationship between chromatin structure, architecture and lncRNA function.
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Affiliation(s)
- Xue Q D Wang
- Department of Biochemistry and Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada
| | - Josée Dostie
- Department of Biochemistry and Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada
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Fabre PJ, Leleu M, Mormann BH, Lopez-Delisle L, Noordermeer D, Beccari L, Duboule D. Large scale genomic reorganization of topological domains at the HoxD locus. Genome Biol 2017; 18:149. [PMID: 28784160 PMCID: PMC5547506 DOI: 10.1186/s13059-017-1278-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/14/2017] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND The transcriptional activation of HoxD genes during mammalian limb development involves dynamic interactions with two topologically associating domains (TADs) flanking the HoxD cluster. In particular, the activation of the most posterior HoxD genes in developing digits is controlled by regulatory elements located in the centromeric TAD (C-DOM) through long-range contacts. RESULTS To assess the structure-function relationships underlying such interactions, we measured compaction levels and TAD discreteness using a combination of chromosome conformation capture (4C-seq) and DNA FISH. We assessed the robustness of the TAD architecture by using a series of genomic deletions and inversions that impact the integrity of this chromatin domain and that remodel long-range contacts. We report multi-partite associations between HoxD genes and up to three enhancers. We find that the loss of native chromatin topology leads to the remodeling of TAD structure following distinct parameters. CONCLUSIONS Our results reveal that the recomposition of TAD architectures after large genomic re-arrangements is dependent on a boundary-selection mechanism in which CTCF mediates the gating of long-range contacts in combination with genomic distance and sequence specificity. Accordingly, the building of a recomposed TAD at this locus depends on distinct functional and constitutive parameters.
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Affiliation(s)
- Pierre J Fabre
- School of Life Sciences, Ecole Polytechnique Fédérale, 1015, Lausanne, Switzerland
| | - Marion Leleu
- School of Life Sciences, Ecole Polytechnique Fédérale, 1015, Lausanne, Switzerland
| | - Benjamin H Mormann
- School of Life Sciences, Ecole Polytechnique Fédérale, 1015, Lausanne, Switzerland
| | | | - Daan Noordermeer
- School of Life Sciences, Ecole Polytechnique Fédérale, 1015, Lausanne, Switzerland.,Present address: Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-sud, University Paris-Saclay, 1 Avenue de la terrasse, 91198, Gif-sur-Yvette, France
| | - Leonardo Beccari
- Department of Genetics and Evolution, University of Geneva, 1211, Geneva 4, Switzerland
| | - Denis Duboule
- School of Life Sciences, Ecole Polytechnique Fédérale, 1015, Lausanne, Switzerland. .,Department of Genetics and Evolution, University of Geneva, 1211, Geneva 4, Switzerland.
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27
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Cao K, Collings CK, Marshall SA, Morgan MA, Rendleman EJ, Wang L, Sze CC, Sun T, Bartom ET, Shilatifard A. SET1A/COMPASS and shadow enhancers in the regulation of homeotic gene expression. Genes Dev 2017; 31:787-801. [PMID: 28487406 PMCID: PMC5435891 DOI: 10.1101/gad.294744.116] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 04/12/2017] [Indexed: 01/16/2023]
Abstract
In this study, Cao et al. identify two cis-regulatory elements (E1 and E2) functioning as shadow enhancers to regulate the early expression of the HoxA genes. Their results reveal multiple regulatory layers for Hox genes to fine-tune transcriptional programs essential for development. The homeotic (Hox) genes are highly conserved in metazoans, where they are required for various processes in development, and misregulation of their expression is associated with human cancer. In the developing embryo, Hox genes are activated sequentially in time and space according to their genomic position within Hox gene clusters. Accumulating evidence implicates both enhancer elements and noncoding RNAs in controlling this spatiotemporal expression of Hox genes, but disentangling their relative contributions is challenging. Here, we identify two cis-regulatory elements (E1 and E2) functioning as shadow enhancers to regulate the early expression of the HoxA genes. Simultaneous deletion of these shadow enhancers in embryonic stem cells leads to impaired activation of HoxA genes upon differentiation, while knockdown of a long noncoding RNA overlapping E1 has no detectable effect on their expression. Although MLL/COMPASS (complex of proteins associated with Set1) family of histone methyltransferases is known to activate transcription of Hox genes in other contexts, we found that individual inactivation of the MLL1-4/COMPASS family members has little effect on early Hox gene activation. Instead, we demonstrate that SET1A/COMPASS is required for full transcriptional activation of multiple Hox genes but functions independently of the E1 and E2 cis-regulatory elements. Our results reveal multiple regulatory layers for Hox genes to fine-tune transcriptional programs essential for development.
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Affiliation(s)
- Kaixiang Cao
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Clayton K Collings
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Stacy A Marshall
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Marc A Morgan
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Emily J Rendleman
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Lu Wang
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Christie C Sze
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Tianjiao Sun
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Elizabeth T Bartom
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Ali Shilatifard
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA.,Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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Expression of progerin does not result in an increased mutation rate. Chromosome Res 2017; 25:227-239. [PMID: 28477268 PMCID: PMC5662688 DOI: 10.1007/s10577-017-9556-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 04/08/2017] [Accepted: 04/13/2017] [Indexed: 12/22/2022]
Abstract
In the premature ageing disease Hutchinson-Gilford progeria syndrome (HGPS), the underlying genetic defect in the lamin A gene leads to accumulation at the nuclear lamina of progerin—a mutant form of lamin A that cannot be correctly processed. This has been reported to result in defects in the DNA damage response and in DNA repair, leading to the hypothesis that, as in normal ageing and in other progeroid syndromes caused by mutation of genes of the DNA repair and DNA damage response pathways, increased DNA damage may be responsible for the premature ageing phenotypes in HGPS patients. However, this hypothesis is based upon the study of markers of the DNA damage response, rather than measurement of DNA damage per se or the consequences of unrepaired DNA damage—mutation. Here, using a mutation reporter cell line, we directly compared the inherent and induced mutation rates in cells expressing wild-type lamin A or progerin. We find no evidence for an elevated mutation rate in progerin-expressing cells. We conclude that the cellular defect in HGPS cells does not lie in the repair of DNA damage per se.
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29
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How does chromatin package DNA within nucleus and regulate gene expression? Int J Biol Macromol 2017; 101:862-881. [PMID: 28366861 DOI: 10.1016/j.ijbiomac.2017.03.165] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/28/2017] [Accepted: 03/28/2017] [Indexed: 01/26/2023]
Abstract
The human body is made up of 60 trillion cells, each cell containing 2 millions of genomic DNA in its nucleus. How is this genomic deoxyribonucleic acid [DNA] organised into nuclei? Around 1880, W. Flemming discovered a nuclear substance that was clearly visible on staining under primitive light microscopes and named it 'chromatin'; this is now thought to be the basic unit of genomic DNA organization. Since long before DNA was known to carry genetic information, chromatin has fascinated biologists. DNA has a negatively charged phosphate backbone that produces electrostatic repulsion between adjacent DNA regions, making it difficult for DNA to fold upon itself. In this article, we will try to shed light on how does chromatin package DNA within nucleus and regulate gene expression?
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Dickerson D, Gierliński M, Singh V, Kitamura E, Ball G, Tanaka TU, Owen-Hughes T. High resolution imaging reveals heterogeneity in chromatin states between cells that is not inherited through cell division. BMC Cell Biol 2016; 17:33. [PMID: 27609610 PMCID: PMC5016949 DOI: 10.1186/s12860-016-0111-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/25/2016] [Indexed: 01/23/2023] Open
Abstract
Background Genomes of eukaryotes exist as chromatin, and it is known that different chromatin states can influence gene regulation. Chromatin is not a static structure, but is known to be dynamic and vary between cells. In order to monitor the organisation of chromatin in live cells we have engineered fluorescent fusion proteins which recognize specific operator sequences to tag pairs of syntenic gene loci. The separation of these loci was then tracked in three dimensions over time using fluorescence microscopy. Results We established a work flow for measuring the distance between two fluorescently tagged, syntenic gene loci with a mean measurement error of 63 nm. In general, physical separation was observed to increase with increasing genomic separations. However, the extent to which chromatin is compressed varies for different genomic regions. No correlation was observed between compaction and the distribution of chromatin markers from genomic datasets or with contacts identified using capture based approaches. Variation in spatial separation was also observed within cells over time and between cells. Differences in the conformation of individual loci can persist for minutes in individual cells. Separation of reporter loci was found to be similar in related and unrelated daughter cell pairs. Conclusions The directly observed physical separation of reporter loci in live cells is highly dynamic both over time and from cell to cell. However, consistent differences in separation are observed over some chromosomal regions that do not correlate with factors known to influence chromatin states. We conclude that as yet unidentified parameters influence chromatin configuration. We also find that while heterogeneity in chromatin states can be maintained for minutes between cells, it is not inherited through cell division. This may contribute to cell-to-cell transcriptional heterogeneity. Electronic supplementary material The online version of this article (doi:10.1186/s12860-016-0111-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- David Dickerson
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Marek Gierliński
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Vijender Singh
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Etsushi Kitamura
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Graeme Ball
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Tomoyuki U Tanaka
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Tom Owen-Hughes
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK. .,Wellcome Trust Building, University of Dundee, Dow Street, Dundee, DD1 5EH, UK.
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31
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Williamson I, Lettice LA, Hill RE, Bickmore WA. Shh and ZRS enhancer colocalisation is specific to the zone of polarising activity. Development 2016; 143:2994-3001. [PMID: 27402708 PMCID: PMC5004883 DOI: 10.1242/dev.139188] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 07/06/2016] [Indexed: 12/28/2022]
Abstract
Limb-specific Shh expression is regulated by the (∼1 Mb distant) ZRS enhancer. In the mouse, limb bud-restricted spatiotemporal Shh expression occurs from ∼E10 to E11.5 at the distal posterior margin and is essential for correct autopod formation. Here, we have analysed the higher-order chromatin conformation of Shh in expressing and non-expressing tissues, both by fluorescence in situ hybridisation (FISH) and by chromosome conformation capture (5C). Conventional and super-resolution light microscopy identified significantly elevated frequencies of Shh/ZRS colocalisation only in the Shh-expressing regions of the limb bud, in a conformation consistent with enhancer-promoter loop formation. However, in all tissues and at all developmental stages analysed, Shh-ZRS spatial distances were still consistently shorter than those to a neural enhancer located between Shh and ZRS in the genome. 5C identified a topologically associating domain (TAD) over the Shh/ZRS genomic region and enriched interactions between Shh and ZRS throughout E11.5 embryos. Shh/ZRS colocalisation, therefore, correlates with the spatiotemporal domain of limb bud-specific Shh expression, but close Shh and ZRS proximity in the nucleus occurs regardless of whether the gene or enhancer is active. We suggest that this constrained chromatin configuration optimises the opportunity for the active enhancer to locate and instigate the expression of Shh. Summary: Super-resolution microscopy reveals that, during mouse limb development, enhancer-driven gene expression results in the juxtaposition of Shh and its limb bud-specific enhancer only within cells of the distal posterior limb bud.
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Affiliation(s)
- Iain Williamson
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, Crewe Road, Edinburgh EH4 2XU, UK
| | - Laura A Lettice
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, Crewe Road, Edinburgh EH4 2XU, UK
| | - Robert E Hill
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, Crewe Road, Edinburgh EH4 2XU, UK
| | - Wendy A Bickmore
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, Crewe Road, Edinburgh EH4 2XU, UK
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32
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MNase titration reveals differences between nucleosome occupancy and chromatin accessibility. Nat Commun 2016; 7:11485. [PMID: 27151365 PMCID: PMC4859066 DOI: 10.1038/ncomms11485] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 03/31/2016] [Indexed: 01/01/2023] Open
Abstract
Chromatin accessibility plays a fundamental role in gene regulation. Nucleosome placement, usually measured by quantifying protection of DNA from enzymatic digestion, can regulate accessibility. We introduce a metric that uses micrococcal nuclease (MNase) digestion in a novel manner to measure chromatin accessibility by combining information from several digests of increasing depths. This metric, MACC (MNase accessibility), quantifies the inherent heterogeneity of nucleosome accessibility in which some nucleosomes are seen preferentially at high MNase and some at low MNase. MACC interrogates each genomic locus, measuring both nucleosome location and accessibility in the same assay. MACC can be performed either with or without a histone immunoprecipitation step, and thereby compares histone and non-histone protection. We find that changes in accessibility at enhancers, promoters and other regulatory regions do not correlate with changes in nucleosome occupancy. Moreover, high nucleosome occupancy does not necessarily preclude high accessibility, which reveals novel principles of chromatin regulation.
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33
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Giusti J, Pinhal D, Moxon S, Campos CL, Münsterberg A, Martins C. MicroRNA-10 modulates Hox genes expression during Nile tilapia embryonic development. Mech Dev 2016; 140:12-8. [DOI: 10.1016/j.mod.2016.03.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 02/12/2016] [Accepted: 03/11/2016] [Indexed: 11/16/2022]
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34
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Vaquerizas JM, Akhtar A, Luscombe NM. Large-scale nuclear architecture and transcriptional control. Subcell Biochem 2016; 52:279-95. [PMID: 21557088 DOI: 10.1007/978-90-481-9069-0_13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Transcriptional regulation is one the most basic mechanisms for controlling gene expression. Over the past few years, much research has been devoted to understanding the interplay between transcription factors, histone modifications and associated enzymes required to achieve this control. However, it is becoming increasingly apparent that the three-dimensional conformation of chromatin in the interphase nucleus also plays a critical role in regulating transcription. Chromatin localisation in the nucleus is highly organised, and early studies described strong interactions between chromatin and sub-nuclear components. Single-gene studies have shed light on how chromosomal architecture affects gene expression. Lately, this has been complemented by whole-genome studies that have determined the global chromatin conformation of living cells in interphase. These studies have greatly expanded our understanding of nuclear architecture and its interplay with different physiological processes. Despite these advances, however, most of the mechanisms used to impose the three-dimensional chromatin structure remain unknown. Here, we summarise the different levels of chromatin organisation in the nucleus and discuss current efforts into characterising the mechanisms that govern it.
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35
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Visualizing the HoxD Gene Cluster at the Nanoscale Level. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2016; 80:9-16. [PMID: 26767994 DOI: 10.1101/sqb.2015.80.027177] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Transcription of HoxD cluster genes in limbs is coordinated by two topologically associating domains (TADs), neighboring the cluster and containing various enhancers. Here, we use a combination of microscopy approaches and chromosome conformation capture to assess the structural changes occurring in this global architecture in various functional states. We observed that despite their spatial juxtaposition, the TADs are consistently kept as distinct three-dimensional units. Hox genes located at their boundary can show significant spatial segregation over long distances, suggesting that physical elongation of the HoxD cluster occurs. The use of superresolution imaging (STORM [stochastic optical reconstruction microscopy]) revealed that the gene cluster can be in an either compact or elongated shape. The latter configuration is observed in transcriptionally active tissue and in embryonic stem cells, consistent with chromosome conformation capture results. Such morphological changes at HoxD in developing digits seem to be associated with its position at the boundary between two TADs and support the idea that chromatin dynamics is important in the establishment of transcriptional activity.
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Fritz A, Barutcu AR, Martin-Buley L, vanWijnen AJ, Zaidi SK, Imbalzano AN, Lian JB, Stein JL, Stein GS. Chromosomes at Work: Organization of Chromosome Territories in the Interphase Nucleus. J Cell Biochem 2016; 117:9-19. [PMID: 26192137 PMCID: PMC4715719 DOI: 10.1002/jcb.25280] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 07/17/2015] [Indexed: 12/26/2022]
Abstract
The organization of interphase chromosomes in chromosome territories (CTs) was first proposed more than one hundred years ago. The introduction of increasingly sophisticated microscopic and molecular techniques, now provide complementary strategies for studying CTs in greater depth than ever before. Here we provide an overview of these strategies and how they are being used to elucidate CT interactions and the role of these dynamically regulated, nuclear-structure building blocks in directly supporting nuclear function in a physiologically responsive manner.
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Affiliation(s)
- Andrew Fritz
- University of Vermont Cancer Center, Department of Biochemistry, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA
| | - A. Rasim Barutcu
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA
| | - Lori Martin-Buley
- University of Vermont Cancer Center, Department of Biochemistry, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA
| | - André J. vanWijnen
- Departments of Orthopedic Surgery and Biochemistry & Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Sayyed K. Zaidi
- University of Vermont Cancer Center, Department of Biochemistry, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA
| | - Anthony N. Imbalzano
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA
| | - Jane B. Lian
- University of Vermont Cancer Center, Department of Biochemistry, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA
| | - Janet L. Stein
- University of Vermont Cancer Center, Department of Biochemistry, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA
| | - Gary S. Stein
- University of Vermont Cancer Center, Department of Biochemistry, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA
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Nanoscale spatial organization of the HoxD gene cluster in distinct transcriptional states. Proc Natl Acad Sci U S A 2015; 112:13964-9. [PMID: 26504220 DOI: 10.1073/pnas.1517972112] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Chromatin condensation plays an important role in the regulation of gene expression. Recently, it was shown that the transcriptional activation of Hoxd genes during vertebrate digit development involves modifications in 3D interactions within and around the HoxD gene cluster. This reorganization follows a global transition from one set of regulatory contacts to another, between two topologically associating domains (TADs) located on either side of the HoxD locus. Here, we use 3D DNA FISH to assess the spatial organization of chromatin at and around the HoxD gene cluster and report that although the two TADs are tightly associated, they appear as spatially distinct units. We measured the relative position of genes within the cluster and found that they segregate over long distances, suggesting that a physical elongation of the HoxD cluster can occur. We analyzed this possibility by super-resolution imaging (STORM) and found that tissues with distinct transcriptional activity exhibit differing degrees of elongation. We also observed that the morphological change of the HoxD cluster in developing digits is associated with its position at the boundary between the two TADs. Such variations in the fine-scale architecture of the gene cluster suggest causal links among its spatial configuration, transcriptional activation, and the flanking chromatin context.
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Sehgal N, Seifert B, Ding H, Chen Z, Stojkovic B, Bhattacharya S, Xu J, Berezney R. Reorganization of the interchromosomal network during keratinocyte differentiation. Chromosoma 2015; 125:389-403. [DOI: 10.1007/s00412-015-0546-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 09/29/2015] [Accepted: 10/01/2015] [Indexed: 10/22/2022]
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Fraser J, Williamson I, Bickmore WA, Dostie J. An Overview of Genome Organization and How We Got There: from FISH to Hi-C. Microbiol Mol Biol Rev 2015; 79:347-72. [PMID: 26223848 PMCID: PMC4517094 DOI: 10.1128/mmbr.00006-15] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In humans, nearly two meters of genomic material must be folded to fit inside each micrometer-scale cell nucleus while remaining accessible for gene transcription, DNA replication, and DNA repair. This fact highlights the need for mechanisms governing genome organization during any activity and to maintain the physical organization of chromosomes at all times. Insight into the functions and three-dimensional structures of genomes comes mostly from the application of visual techniques such as fluorescence in situ hybridization (FISH) and molecular approaches including chromosome conformation capture (3C) technologies. Recent developments in both types of approaches now offer the possibility of exploring the folded state of an entire genome and maybe even the identification of how complex molecular machines govern its shape. In this review, we present key methodologies used to study genome organization and discuss what they reveal about chromosome conformation as it relates to transcription regulation across genomic scales in mammals.
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Affiliation(s)
- James Fraser
- Department of Biochemistry, and Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada
| | - Iain Williamson
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Wendy A Bickmore
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Josée Dostie
- Department of Biochemistry, and Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada
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Srivastava S, Dhawan J, Mishra RK. Epigenetic mechanisms and boundaries in the regulation of mammalian Hox clusters. Mech Dev 2015; 138 Pt 2:160-169. [PMID: 26254900 DOI: 10.1016/j.mod.2015.07.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 07/29/2015] [Accepted: 07/30/2015] [Indexed: 01/07/2023]
Abstract
Hox gene expression imparts segment identity to body structures along the anterior-posterior axis and is tightly governed by higher order chromatin mechanisms. Chromatin regulatory features of the homeotic complex are best defined in Drosophila melanogaster, where multiple cis-regulatory elements have been identified that ensure collinear Hox gene expression patterns in accordance with their genomic organization. Recent studies focused on delineating the epigenetic features of the vertebrate Hox clusters have helped reveal their dynamic chromatin organization and its impact on gene expression. Enrichment for the 'activating' H3K4me3 and 'repressive' H3K27me3 histone modifications is a particularly strong read-out for transcriptional status and correlates well with the evidence for chromatin loop domain structures and stage specific topological changes at these loci. However, it is not clear how such distinct domains are imposed and regulated independent of each other. Comparative analysis of the chromatin structure and organization of the homeotic gene clusters in fly and mammals is increasingly revealing the functional conservation of chromatin mediated mechanisms. Here we discuss the case for interspersed boundary elements existing within mammalian Hox clusters along with their possible roles and mechanisms of action. Recent studies suggest a role for factors other than the well characterized vertebrate boundary factor CTCF, such as the GAGA binding factor (GAF), in maintaining chromatin domains at the Hox loci. We also present data demonstrating how such regulatory elements may be involved in organizing higher order structure and demarcating active domains of gene expression at the mammalian Hox clusters.
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Affiliation(s)
- Surabhi Srivastava
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India.
| | - Jyotsna Dhawan
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
| | - Rakesh K Mishra
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
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Rafique S, Thomas JS, Sproul D, Bickmore WA. Estrogen-induced chromatin decondensation and nuclear re-organization linked to regional epigenetic regulation in breast cancer. Genome Biol 2015; 16:145. [PMID: 26235388 PMCID: PMC4536608 DOI: 10.1186/s13059-015-0719-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 07/06/2015] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Epigenetic changes are being increasingly recognized as a prominent feature of cancer. This occurs not only at individual genes, but also over larger chromosomal domains. To investigate this, we set out to identify large chromosomal domains of epigenetic dysregulation in breast cancers. RESULTS We identify large regions of coordinate down-regulation of gene expression, and other regions of coordinate activation, in breast cancers and show that these regions are linked to tumor subtype. In particular we show that a group of coordinately regulated regions are expressed in luminal, estrogen-receptor positive breast tumors and cell lines. For one of these regions of coordinate gene activation, we show that regional epigenetic regulation is accompanied by visible unfolding of large-scale chromatin structure and a repositioning of the region within the nucleus. In MCF7 cells, we show that this depends on the presence of estrogen. CONCLUSIONS Our data suggest that the liganded estrogen receptor is linked to long-range changes in higher-order chromatin organization and epigenetic dysregulation in cancer. This may suggest that as well as drugs targeting histone modifications, it will be valuable to investigate the inhibition of protein complexes involved in chromatin folding in cancer cells.
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Affiliation(s)
- Sehrish Rafique
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh, EH4 2XU, UK. .,Edinburgh Breakthrough Research Unit and Edinburgh Cancer Centre, University of Edinburgh, Western General Hospital, Crewe Road South, Edinburgh, Scotland, EH4 2XU, UK.
| | - Jeremy S Thomas
- Edinburgh Breakthrough Research Unit and Edinburgh Cancer Centre, University of Edinburgh, Western General Hospital, Crewe Road South, Edinburgh, Scotland, EH4 2XU, UK.
| | - Duncan Sproul
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh, EH4 2XU, UK. .,Edinburgh Breakthrough Research Unit and Edinburgh Cancer Centre, University of Edinburgh, Western General Hospital, Crewe Road South, Edinburgh, Scotland, EH4 2XU, UK.
| | - Wendy A Bickmore
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh, EH4 2XU, UK.
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42
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Abstract
Chromatin, once thought to serve only as a means to package DNA, is now recognized as a major regulator of gene activity. As a result of the wide range of methods used to describe the numerous levels of chromatin organization, the terminology that has emerged to describe these organizational states is often imprecise and sometimes misleading. In this review, we discuss our current understanding of chromatin architecture and propose terms to describe the various biochemical and structural states of chromatin.
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Affiliation(s)
- Liron Even-Faitelson
- Program in Genetics and Genome Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON, M5G 0A4, Canada
| | | | - Zahra Baghestani
- Program in Genetics and Genome Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON, M5G 0A4, Canada
| | - David P Bazett-Jones
- Program in Genetics and Genome Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON, M5G 0A4, Canada.
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43
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Lopes Novo C, Rugg-Gunn PJ. Chromatin organization in pluripotent cells: emerging approaches to study and disrupt function. Brief Funct Genomics 2015. [PMID: 26206085 PMCID: PMC4958138 DOI: 10.1093/bfgp/elv029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Translating the vast amounts of genomic and epigenomic information accumulated on the linear genome into three-dimensional models of nuclear organization is a current major challenge. In response to this challenge, recent technological innovations based on chromosome conformation capture methods in combination with increasingly powerful functional approaches have revealed exciting insights into key aspects of genome regulation. These findings have led to an emerging model where the genome is folded and compartmentalized into highly conserved topological domains that are further divided into functional subdomains containing physical loops that bring cis-regulatory elements to close proximity. Targeted functional experiments, largely based on designable DNA-binding proteins, have begun to define the major architectural proteins required to establish and maintain appropriate genome regulation. Here, we focus on the accessible and well-characterized system of pluripotent cells to review the functional role of chromatin organization in regulating pluripotency, differentiation and reprogramming.
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44
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Gorkin DU, Leung D, Ren B. The 3D genome in transcriptional regulation and pluripotency. Cell Stem Cell 2015; 14:762-75. [PMID: 24905166 DOI: 10.1016/j.stem.2014.05.017] [Citation(s) in RCA: 286] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
It can be convenient to think of the genome as simply a string of nucleotides, the linear order of which encodes an organism's genetic blueprint. However, the genome does not exist as a linear entity within cells where this blueprint is actually utilized. Inside the nucleus, the genome is organized in three-dimensional (3D) space, and lineage-specific transcriptional programs that direct stem cell fate are implemented in this native 3D context. Here, we review principles of 3D genome organization in mammalian cells. We focus on the emerging relationship between genome organization and lineage-specific transcriptional regulation, which we argue are inextricably linked.
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Affiliation(s)
- David U Gorkin
- Ludwig Institute for Cancer Research, 9500 Gilman Drive, La Jolla, CA 92093, USA.
| | - Danny Leung
- Ludwig Institute for Cancer Research, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Bing Ren
- Ludwig Institute for Cancer Research, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, Institute of Genome Medicine, Moores Cancer Center, University of California, San Diego, School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA.
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45
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Vieux-Rochas M, Fabre PJ, Leleu M, Duboule D, Noordermeer D. Clustering of mammalian Hox genes with other H3K27me3 targets within an active nuclear domain. Proc Natl Acad Sci U S A 2015; 112:4672-7. [PMID: 25825760 PMCID: PMC4403207 DOI: 10.1073/pnas.1504783112] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Embryogenesis requires the precise activation and repression of many transcriptional regulators. The Polycomb group proteins and the associated H3K27me3 histone mark are essential to maintain the inactive state of many of these genes. Mammalian Hox genes are targets of Polycomb proteins and form local 3D clusters centered on the H3K27me3 mark. More distal contacts have also been described, yet their selectivity, dynamics, and relation to other layers of chromatin organization remained elusive. We report that repressed Hox genes form mutual intra- and interchromosomal interactions with other genes located in strong domains labeled by H3K27me3. These interactions occur in a central and active nuclear environment that consists of the HiC compartment A, away from peripheral lamina-associated domains. Interactions are independent of nearby H3K27me3-marked loci and determined by chromosomal distance and cell-type-specific scaling factors, thus inducing a moderate reorganization during embryogenesis. These results provide a simplified view of nuclear organization whereby Polycomb proteins may have evolved to repress genes located in gene-dense regions whose position is restricted to central, active, nuclear environments.
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Affiliation(s)
- Maxence Vieux-Rochas
- School of Life Sciences, Swiss Federal Institute of Technology - Lausanne (EPFL), 1015 Lausanne, Switzerland; and
| | - Pierre J Fabre
- School of Life Sciences, Swiss Federal Institute of Technology - Lausanne (EPFL), 1015 Lausanne, Switzerland; and
| | - Marion Leleu
- School of Life Sciences, Swiss Federal Institute of Technology - Lausanne (EPFL), 1015 Lausanne, Switzerland; and
| | - Denis Duboule
- School of Life Sciences, Swiss Federal Institute of Technology - Lausanne (EPFL), 1015 Lausanne, Switzerland; and Department of Genetics and Evolution, University of Geneva, 1205 Geneva, Switzerland
| | - Daan Noordermeer
- School of Life Sciences, Swiss Federal Institute of Technology - Lausanne (EPFL), 1015 Lausanne, Switzerland; and
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46
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Vallot C, Hérault A, Boyle S, Bickmore WA, Radvanyi F. PRC2-independent chromatin compaction and transcriptional repression in cancer. Oncogene 2015; 34:741-51. [PMID: 24469045 DOI: 10.1038/onc.2013.604] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 12/10/2013] [Accepted: 12/20/2013] [Indexed: 12/13/2022]
Abstract
The silencing of large chromosomal regions by epigenetic mechanisms has been reported to occur frequently in cancer. Epigenetic marks, such as histone methylation and acetylation, are altered at these loci. However, the mechanisms of formation of such aberrant gene clusters remain largely unknown. Here, we show that, in cancer cells, the epigenetic remodeling of chromatin into hypoacetylated domains covered with histone H3K27 trimethylation is paralleled by changes in higher-order chromatin structures. Using fluorescence in situ hybridization, we demonstrate that regional epigenetic silencing corresponds to the establishment of compact chromatin domains. We show that gene repression is tightly correlated to the state of chromatin compaction and not to the levels of H3K27me3-its removal through the knockdown of EZH2 does not induce significant gene expression nor chromatin decompaction. Moreover, transcription can occur with intact high-H3K27me3 levels; treatment with histone deacetylase inhibitors can relieve chromatin compaction and gene repression, without altering H3K27me3 levels. Our findings imply that compaction and subsequent repression of large chromatin domains are not direct consequences of PRC2 deregulation in cancer cells. By challenging the role of EZH2 in aberrant gene silencing in cancer, these findings have therapeutical implications, notably for the choice of epigenetic drugs for tumors with multiple regional epigenetic alterations.
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Affiliation(s)
- C Vallot
- 1] CNRS, UMR 144 - Cell Biology Department, Institut Curie, Paris, France [2] Institut Curie, Centre de Recherche, Paris, France
| | - A Hérault
- 1] CNRS, UMR 144 - Cell Biology Department, Institut Curie, Paris, France [2] Institut Curie, Centre de Recherche, Paris, France
| | - S Boyle
- Chromosome and Gene Expression Section, MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Scotland, UK
| | - W A Bickmore
- 1] Chromosome and Gene Expression Section, MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Scotland, UK [2] Breakthrough Breast Cancer Research Unit, University of Edinburgh, Scotland, UK
| | - F Radvanyi
- 1] CNRS, UMR 144 - Cell Biology Department, Institut Curie, Paris, France [2] Institut Curie, Centre de Recherche, Paris, France
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47
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Therizols P, Illingworth RS, Courilleau C, Boyle S, Wood AJ, Bickmore WA. Chromatin decondensation is sufficient to alter nuclear organization in embryonic stem cells. Science 2014; 346:1238-42. [PMID: 25477464 DOI: 10.1126/science.1259587] [Citation(s) in RCA: 209] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
During differentiation, thousands of genes are repositioned toward or away from the nuclear envelope. These movements correlate with changes in transcription and replication timing. Using synthetic (TALE) transcription factors, we found that transcriptional activation of endogenous genes by a viral trans-activator is sufficient to induce gene repositioning toward the nuclear interior in embryonic stem cells. However, gene relocation was also induced by recruitment of an acidic peptide that decondenses chromatin without affecting transcription, indicating that nuclear reorganization is driven by chromatin remodeling rather than transcription. We identified an epigenetic inheritance of chromatin decondensation that maintained central nuclear positioning through mitosis even after the TALE transcription factor was lost. Our results also demonstrate that transcriptional activation, but not chromatin decondensation, is sufficient to change replication timing.
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Affiliation(s)
- Pierre Therizols
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Robert S Illingworth
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Celine Courilleau
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Shelagh Boyle
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Andrew J Wood
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Wendy A Bickmore
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK.
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48
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Williamson I, Berlivet S, Eskeland R, Boyle S, Illingworth RS, Paquette D, Dostie J, Bickmore WA. Spatial genome organization: contrasting views from chromosome conformation capture and fluorescence in situ hybridization. Genes Dev 2014; 28:2778-91. [PMID: 25512564 PMCID: PMC4265680 DOI: 10.1101/gad.251694.114] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 10/30/2014] [Indexed: 01/28/2023]
Abstract
Although important for gene regulation, most studies of genome organization use either fluorescence in situ hybridization (FISH) or chromosome conformation capture (3C) methods. FISH directly visualizes the spatial relationship of sequences but is usually applied to a few loci at a time. The frequency at which sequences are ligated together by formaldehyde cross-linking can be measured genome-wide by 3C methods, with higher frequencies thought to reflect shorter distances. FISH and 3C should therefore give the same views of genome organization, but this has not been tested extensively. We investigated the murine HoxD locus with 3C carbon copy (5C) and FISH in different developmental and activity states and in the presence or absence of epigenetic regulators. We identified situations in which the two data sets are concordant but found other conditions under which chromatin topographies extrapolated from 5C or FISH data are not compatible. We suggest that products captured by 3C do not always reflect spatial proximity, with ligation occurring between sequences located hundreds of nanometers apart, influenced by nuclear environment and chromatin composition. We conclude that results obtained at high resolution with either 3C methods or FISH alone must be interpreted with caution and that views about genome organization should be validated by independent methods.
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Affiliation(s)
- Iain Williamson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Soizik Berlivet
- Department of Biochemistry, Goodman Cancer Research Center, McGill University, Montréal, Québec H3G1Y6, Canada
| | - Ragnhild Eskeland
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Shelagh Boyle
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Robert S Illingworth
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | | | | | - Wendy A Bickmore
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom;
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49
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Yu P, McKinney EC, Kandasamy MM, Albert AL, Meagher RB. Characterization of brain cell nuclei with decondensed chromatin. Dev Neurobiol 2014; 75:738-56. [PMID: 25369517 DOI: 10.1002/dneu.22245] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 10/22/2014] [Accepted: 10/30/2014] [Indexed: 12/14/2022]
Abstract
Although multipotent cell types have enlarged nuclei with decondensed chromatin, this property has not been exploited to enhance the characterization of neural progenitor cell (NPC) populations in the brain. We found that mouse brain cell nuclei that expressed exceptionally high levels of the pan neuronal marker NeuN/FOX3 (NeuN-High) had decondensed chromatin relative to most NeuN-Low or NeuN-Neg (negative) nuclei. Purified NeuN-High nuclei expressed significantly higher levels of transcripts encoding markers of neurogenesis, neuroplasticity, and learning and memory (ARC, BDNF, ERG1, HOMER1, NFL/NEF1, SYT1), subunits of chromatin modifying machinery (SIRT1, HDAC1, HDAC2, HDAC11, KAT2B, KAT3A, KAT3B, KAT5, DMNT1, DNMT3A, Gadd45a, Gadd45b) and markers of NPC and cell cycle activity (BRN2, FOXG1, KLF4, c-MYC, OCT4, PCNA, SHH, SOX2) relative to neuronal NeuN-Low or to mostly non-neuronal NeuN-Neg nuclei. NeuN-High nuclei expressed higher levels of HDAC1, 2, 4, and 5 proteins. The cortex, hippocampus, hypothalamus, thalamus, and nucleus accumbens contained high percentages of large decondensed NeuN-High nuclei, while the cerebellum, and pons contained very few. NeuN-High nuclei have the properties consistent with their being derived from extremely active neurons with elevated rates of chromatin modification and/or NPC-like cells with multilineage developmental potential. The further analysis of decondensed neural cell nuclei should provide novel insights into neurobiology and neurodegenerative disease.
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Affiliation(s)
- Ping Yu
- Department of Genetics, University of Georgia, Davison Life Sciences Building, Athens, Georgia, 30602
| | - Elizabeth C McKinney
- Department of Genetics, University of Georgia, Davison Life Sciences Building, Athens, Georgia, 30602
| | - Muthugapatti M Kandasamy
- Department of Genetics, University of Georgia, Davison Life Sciences Building, Athens, Georgia, 30602
| | | | - Richard B Meagher
- Department of Genetics, University of Georgia, Davison Life Sciences Building, Athens, Georgia, 30602
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50
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Dubois A, Deuve JL, Navarro P, Merzouk S, Pichard S, Commere PH, Louise A, Arnaud D, Avner P, Morey C. Spontaneous reactivation of clusters of X-linked genes is associated with the plasticity of X-inactivation in mouse trophoblast stem cells. Stem Cells 2014; 32:377-90. [PMID: 24115267 DOI: 10.1002/stem.1557] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 07/29/2013] [Accepted: 08/13/2013] [Indexed: 12/21/2022]
Abstract
Random epigenetic silencing of the X-chromosome in somatic tissues of female mammals equalizes the dosage of X-linked genes between the sexes. Unlike this form of X-inactivation that is essentially irreversible, the imprinted inactivation of the paternal X, which characterizes mouse extra-embryonic tissues, appears highly unstable in the trophoblast giant cells of the placenta. Here, we wished to determine whether such instability is already present in placental progenitor cells prior to differentiation toward lineage-specific cell types. To this end, we analyzed the behavior of a GFP transgene on the paternal X both in vivo and in trophoblast stem (TS) cells derived from the trophectoderm of XX(GFP) blastocysts. Using single-cell studies, we show that not only the GFP transgene but also a large number of endogenous genes on the paternal X are subject to orchestrated cycles of reactivation/de novo inactivation in placental progenitor cells. This reversal of silencing is associated with local losses of histone H3 lysine 27 trimethylation extending over several adjacent genes and with the topological relocation of the hypomethylated loci outside of the nuclear compartment of the inactive X. The "reactivated" state is maintained through several cell divisions. Our study suggests that this type of "metastable epigenetic" states may underlie the plasticity of TS cells and predispose specific genes to relaxed regulation in specific subtypes of placental cells.
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Affiliation(s)
- Agnès Dubois
- Unité de Génétique Moléculaire Murine, Institut Pasteur, Paris Cedex 15, France; Epigenetics of Stem Cells, Institut Pasteur, Paris Cedex 15, France
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