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Valades-Cruz CA, Barth R, Abdellah M, Shaban HA. Genome-wide analysis of the biophysical properties of chromatin and nuclear proteins in living cells with Hi-D. Nat Protoc 2024:10.1038/s41596-024-01038-3. [PMID: 39198619 DOI: 10.1038/s41596-024-01038-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 04/22/2024] [Indexed: 09/01/2024]
Abstract
To understand the dynamic nature of the genome, the localization and rearrangement of DNA and DNA-binding proteins must be analyzed across the entire nucleus of single living cells. Recently, we developed a computational light microscopy technique, called high-resolution diffusion (Hi-D) mapping, which can accurately detect, classify and map diffusion dynamics and biophysical parameters such as the diffusion constant, the anomalous exponent, drift velocity and model physical diffusion from the data at a high spatial resolution across the genome in living cells. Hi-D combines dense optical flow to detect and track local chromatin and nuclear protein motion genome-wide and Bayesian inference to characterize this local movement at nanoscale resolution. Here we present the Python implementation of Hi-D, with an option for parallelizing the calculations to run on multicore central processing units (CPUs). The functionality of Hi-D is presented to the users via user-friendly documented Python notebooks. Hi-D reduces the analysis time to less than 1 h using a multicore CPU with a single compute node. We also present different applications of Hi-D for live-imaging of DNA, histone H2B and RNA polymerase II sequences acquired with spinning disk confocal and super-resolution structured illumination microscopy.
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Affiliation(s)
- Cesar Augusto Valades-Cruz
- SERPICO Project Team, Inria Centre Rennes-Bretagne Atlantique, Rennes, France
- SERPICO Project Team, UMR144 CNRS Institut Curie, PSL Research University, Paris, France
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Roman Barth
- Department of Bionanoscience, Delft University of Technology, Delft, the Netherlands
| | - Marwan Abdellah
- Ecole polytechnique fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Haitham A Shaban
- Spectroscopy Department, Institute of Physics Research National Research Centre, Cairo, Egypt.
- Agora Cancer Research Center, Lausanne, Switzerland.
- Precision Oncology Center, Department of Oncology Lausanne University Hospital, Lausanne, Switzerland.
- Faculty of Medicine, University of Geneva, Geneva, Switzerland.
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2
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Pessoa J, Carvalho C. Human RNA Polymerase II Segregates from Genes and Nascent RNA and Transcribes in the Presence of DNA-Bound dCas9. Int J Mol Sci 2024; 25:8411. [PMID: 39125980 PMCID: PMC11312690 DOI: 10.3390/ijms25158411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Revised: 07/21/2024] [Accepted: 07/27/2024] [Indexed: 08/12/2024] Open
Abstract
RNA polymerase II (Pol II) dysfunction is frequently implied in human disease. Understanding its functional mechanism is essential for designing innovative therapeutic strategies. To visualize its supra-molecular interactions with genes and nascent RNA, we generated a human cell line carrying ~335 consecutive copies of a recombinant β-globin gene. Confocal microscopy showed that Pol II was not homogeneously concentrated around these identical gene copies. Moreover, Pol II signals partially overlapped with the genes and their nascent RNA, revealing extensive compartmentalization. Using a cell line carrying a single copy of the β-globin gene, we also tested if the binding of catalytically dead CRISPR-associated system 9 (dCas9) to different gene regions affected Pol II transcriptional activity. We assessed Pol II localization and nascent RNA levels using chromatin immunoprecipitation and droplet digital reverse transcription PCR, respectively. Some enrichment of transcriptionally paused Pol II accumulated in the promoter region was detected in a strand-specific way of gRNA binding, and there was no decrease in nascent RNA levels. Pol II preserved its transcriptional activity in the presence of DNA-bound dCas9. Our findings contribute further insight into the complex mechanism of mRNA transcription in human cells.
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Affiliation(s)
- João Pessoa
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal;
- Department of Medical Sciences and Institute of Biomedicine—iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Célia Carvalho
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal;
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3
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Shaban HA, Friman ET, Deluz C, Tollenaere A, Katanayeva N, Suter DM. Individual transcription factors modulate both the micromovement of chromatin and its long-range structure. Proc Natl Acad Sci U S A 2024; 121:e2311374121. [PMID: 38648478 PMCID: PMC11067044 DOI: 10.1073/pnas.2311374121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 03/13/2024] [Indexed: 04/25/2024] Open
Abstract
The control of eukaryotic gene expression is intimately connected to highly dynamic chromatin structures. Gene regulation relies on activator and repressor transcription factors (TFs) that induce local chromatin opening and closing. However, it is unclear how nucleus-wide chromatin organization responds dynamically to the activity of specific TFs. Here, we examined how two TFs with opposite effects on local chromatin accessibility modulate chromatin dynamics nucleus-wide. We combine high-resolution diffusion mapping and dense flow reconstruction and correlation in living cells to obtain an imaging-based, nanometer-scale analysis of local diffusion processes and long-range coordinated movements of both chromatin and TFs. We show that the expression of either an individual transcriptional activator (CDX2) or repressor (SIX6) with large numbers of binding sites increases chromatin mobility nucleus-wide, yet they induce opposite coherent chromatin motions at the micron scale. Hi-C analysis of higher-order chromatin structures shows that induction of the pioneer factor CDX2 leads both to changes in local chromatin interactions and the distribution of A and B compartments, thus relating the micromovement of chromatin with changes in compartmental structures. Given that inhibition of transcription initiation and elongation by RNA Pol II has a partial impact on the global chromatin dynamics induced by CDX2, we suggest that CDX2 overexpression alters chromatin structure dynamics both dependently and independently of transcription. Our biophysical analysis shows that sequence-specific TFs can influence chromatin structure on multiple architectural levels, arguing that local chromatin changes brought by TFs alter long-range chromatin mobility and its organization.
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Affiliation(s)
- Haitham A. Shaban
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, LausanneCH-1015, Switzerland
- Spectroscopy Department, Institute of Physics Research, National Research Centre, Cairo12622, Egypt
| | - Elias T. Friman
- Medical Research Council Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, EdinburghEH4 2XU, United Kingdom
| | - Cédric Deluz
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, LausanneCH-1015, Switzerland
| | - Armelle Tollenaere
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, LausanneCH-1015, Switzerland
| | - Natalya Katanayeva
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, LausanneCH-1015, Switzerland
| | - David M. Suter
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, LausanneCH-1015, Switzerland
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4
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Woodworth MA, Lakadamyali M. Toward a comprehensive view of gene architecture during transcription. Curr Opin Genet Dev 2024; 85:102154. [PMID: 38309073 PMCID: PMC10989512 DOI: 10.1016/j.gde.2024.102154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/20/2023] [Accepted: 01/09/2024] [Indexed: 02/05/2024]
Abstract
The activation of genes within the nucleus of eukaryotic cells is a tightly regulated process, orchestrated by a complex interplay of various physical properties and interacting factors. Studying the multitude of components and features that collectively contribute to gene activation has proven challenging due to the complexities of simultaneously visualizing the dynamic and transiently interacting elements that coalesce within the small space occupied by each individual gene. However, various labeling and imaging advances are now starting to overcome this challenge, enabling visualization of gene activation at different lengths and timescales. In this review, we aim to highlight these microscopy-based advances and suggest how they can be combined to provide a comprehensive view of the mechanisms regulating gene activation.
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Affiliation(s)
- Marcus A Woodworth
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Melike Lakadamyali
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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5
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Das R, Sakaue T, Shivashankar GV, Prost J, Hiraiwa T. Chromatin Remodeling Due to Transient-Link-and-Pass Activity Enhances Subnuclear Dynamics. PHYSICAL REVIEW LETTERS 2024; 132:058401. [PMID: 38364140 DOI: 10.1103/physrevlett.132.058401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 01/02/2024] [Indexed: 02/18/2024]
Abstract
Spatiotemporal coordination of chromatin and subnuclear compartments is crucial for cells. Numerous enzymes act inside nucleus-some of those transiently link and pass two chromatin segments. Here, we study how such an active perturbation affects fluctuating dynamics of an inclusion in the chromatic medium. Using numerical simulations and a versatile effective model, we categorize inclusion dynamics into three distinct modes. The transient-link-and-pass activity speeds up inclusion dynamics by affecting a slow mode related to chromatin remodeling, viz., size and shape of the chromatin meshes.
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Affiliation(s)
- Rakesh Das
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
| | - Takahiro Sakaue
- Department of Physical Sciences, Aoyama Gakuin University, Kanagawa 252-5258, Japan
| | - G V Shivashankar
- Department of Health Sciences and Technology (D-HEST), ETH Zurich, Villigen 8092, Switzerland
- Division of Biology and Chemistry, Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Jacques Prost
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
- Laboratoire Physico Chimie Curie, Institut Curie, Paris Science et Lettres Research University, 75005 Paris, France
| | - Tetsuya Hiraiwa
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
- Institute of Physics, Academia Sinica, Taipei City 115201, Taiwan
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Abrhámová K, Groušlová M, Valentová A, Hao X, Liu B, Převorovský M, Gahura O, Půta F, Sunnerhagen P, Folk P. Truncating the spliceosomal 'rope protein' Prp45 results in Htz1 dependent phenotypes. RNA Biol 2024; 21:1-17. [PMID: 38711165 PMCID: PMC11085953 DOI: 10.1080/15476286.2024.2348896] [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] [Accepted: 04/24/2024] [Indexed: 05/08/2024] Open
Abstract
Spliceosome assembly contributes an important but incompletely understood aspect of splicing regulation. Prp45 is a yeast splicing factor which runs as an extended fold through the spliceosome, and which may be important for bringing its components together. We performed a whole genome analysis of the genetic interaction network of the truncated allele of PRP45 (prp45(1-169)) using synthetic genetic array technology and found chromatin remodellers and modifiers as an enriched category. In agreement with related studies, H2A.Z-encoding HTZ1, and the components of SWR1, INO80, and SAGA complexes represented prominent interactors, with htz1 conferring the strongest growth defect. Because the truncation of Prp45 disproportionately affected low copy number transcripts of intron-containing genes, we prepared strains carrying intronless versions of SRB2, VPS75, or HRB1, the most affected cases with transcription-related function. Intron removal from SRB2, but not from the other genes, partly repaired some but not all the growth phenotypes identified in the genetic screen. The interaction of prp45(1-169) and htz1Δ was detectable even in cells with SRB2 intron deleted (srb2Δi). The less truncated variant, prp45(1-330), had a synthetic growth defect with htz1Δ at 16°C, which also persisted in the srb2Δi background. Moreover, htz1Δ enhanced prp45(1-330) dependent pre-mRNA hyper-accumulation of both high and low efficiency splicers, genes ECM33 and COF1, respectively. We conclude that while the expression defects of low expression intron-containing genes contribute to the genetic interactome of prp45(1-169), the genetic interactions between prp45 and htz1 alleles demonstrate the sensitivity of spliceosome assembly, delayed in prp45(1-169), to the chromatin environment.
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Affiliation(s)
- Kateřina Abrhámová
- Department of Cell Biology, Faculty of Science, Charles University, Praha, Czech Republic
| | - Martina Groušlová
- Department of Cell Biology, Faculty of Science, Charles University, Praha, Czech Republic
| | - Anna Valentová
- Department of Cell Biology, Faculty of Science, Charles University, Praha, Czech Republic
| | - Xinxin Hao
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Beidong Liu
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Martin Převorovský
- Department of Cell Biology, Faculty of Science, Charles University, Praha, Czech Republic
| | - Ondřej Gahura
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - František Půta
- Department of Cell Biology, Faculty of Science, Charles University, Praha, Czech Republic
| | - Per Sunnerhagen
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Petr Folk
- Department of Cell Biology, Faculty of Science, Charles University, Praha, Czech Republic
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7
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Sylvers J, Wang Y, Yuan F. Nuclear Entry of DNA and Transgene Expression in Dividing and Non-dividing Cells. Cell Mol Bioeng 2023; 16:459-474. [PMID: 38099212 PMCID: PMC10716082 DOI: 10.1007/s12195-023-00784-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 09/03/2023] [Indexed: 12/17/2023] Open
Abstract
Introduction Plasmid DNA (pDNA) must be delivered into the nucleus for transgene expression in mammalian cells. The entry may happen passively during the nuclear envelope breakdown and reformation in dividing cells or actively through the nuclear pore complexes. The goal of this study was to investigate the relative importance of these two pathways for pDNA nuclear entry and subsequent gene expression. Methods To measure nuclear entry of pDNA encoding enhanced green florescence protein (EGFP) in electrotransfected cells, we developed a sensitive technique for quantitative analysis of pDNA in the nuclei, based on a hybridization probe for pDNA detection at the single molecule level and automatic image analysis. In matched experiments, we used an mRNA targeted hybridization probe to quantify reporter mRNA expression per cell, and flow cytometry to quantify expression of EGFP. Results We discovered two distinct patterns of pDNA distribution in the nuclei: punctate and diffuse, which were dominant in arrested and unarrested cells, respectively. The cell cycle arrest decreased diffuse pDNA and increased punctate pDNA. Its net effect was a decrease in the total intranuclear pDNA. Additionally, the cell cycle arrest increased the reporter mRNA synthesis but had no substantial impact on reporter protein expression. Conclusion Results from the study demonstrated that the efficient nuclear entry of pDNA during cell division did not necessarily lead to a high level of transgene expression. They also suggested that the punctate pDNA was more transcriptionally active than diffuse pDNA in the nuclei. These data will be useful in future studies for understanding mechanisms of nonviral gene delivery.
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Affiliation(s)
- Justin Sylvers
- Department of Biomedical Engineering, Duke University, Durham, NC 27708 USA
| | - Yifei Wang
- Department of Biomedical Engineering, Duke University, Durham, NC 27708 USA
| | - Fan Yuan
- Department of Biomedical Engineering, Duke University, Durham, NC 27708 USA
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8
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Salafranca J, Ko JK, Mukherjee AK, Fritzsche M, van Grinsven E, Udalova IA. Neutrophil nucleus: shaping the past and the future. J Leukoc Biol 2023; 114:585-594. [PMID: 37480361 PMCID: PMC10673716 DOI: 10.1093/jleuko/qiad084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 07/10/2023] [Accepted: 07/12/2023] [Indexed: 07/24/2023] Open
Abstract
Neutrophils are innate immune cells that are key to protecting the host against infection and maintaining body homeostasis. However, if dysregulated, they can contribute to disease, such as in cancer or chronic autoinflammatory disorders. Recent studies have highlighted the heterogeneity in the neutrophil compartment and identified the presence of immature neutrophils and their precursors in these pathologies. Therefore, understanding neutrophil maturity and the mechanisms through which they contribute to disease is critical. Neutrophils were first characterized morphologically by Ehrlich in 1879 using microscopy, and since then, different technologies have been used to assess neutrophil maturity. The advances in the imaging field, including state-of-the-art microscopy and machine learning algorithms for image analysis, reinforce the use of neutrophil nuclear morphology as a fundamental marker of maturity, applicable for objective classification in clinical diagnostics. New emerging approaches, such as the capture of changes in chromatin topology, will provide mechanistic links between the nuclear shape, chromatin organization, and transcriptional regulation during neutrophil maturation.
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Affiliation(s)
- Julia Salafranca
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Jacky Ka Ko
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Ananda K Mukherjee
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Marco Fritzsche
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Erinke van Grinsven
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Irina A Udalova
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
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9
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Chen LF, Lee J, Boettiger A. Recent progress and challenges in single-cell imaging of enhancer-promoter interaction. Curr Opin Genet Dev 2023; 79:102023. [PMID: 36854248 DOI: 10.1016/j.gde.2023.102023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 01/13/2023] [Accepted: 01/25/2023] [Indexed: 02/27/2023]
Abstract
In the past two years, approaches relying on high-resolution microscopy and live-cell imaging have increasingly contributed to our understanding of the 3D genome organization and its importance for transcriptional control. Here, we describe recent progress that has highlighted how flexible and heterogeneous 3D chromatin structure is, on the length scales relevant to transcriptional control. We describe work that has investigated how robust transcriptional outcomes may be derived from such flexible organization without the need for clearly distinct structures in active and silent cells. We survey the latest state of the art in directly observing the dynamics of chromatin interactions, and suggest how some recent, apparently contradictory conclusions may be reconciled.
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Affiliation(s)
- Liang-Fu Chen
- Department of Chemical and Systems Biology, Stanford University, USA
| | - Joo Lee
- Department of Developmental Biology, Stanford University, USA
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10
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Ball ML, Koestler SA, Muresan L, Rehman SA, O’Holleran K, White R. The anatomy of transcriptionally active chromatin loops in Drosophila primary spermatocytes using super-resolution microscopy. PLoS Genet 2023; 19:e1010654. [PMID: 36867662 PMCID: PMC10016678 DOI: 10.1371/journal.pgen.1010654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 03/15/2023] [Accepted: 02/04/2023] [Indexed: 03/04/2023] Open
Abstract
While the biochemistry of gene transcription has been well studied, our understanding of how this process is organised in 3D within the intact nucleus is less well understood. Here we investigate the structure of actively transcribed chromatin and the architecture of its interaction with active RNA polymerase. For this analysis, we have used super-resolution microscopy to image the Drosophila melanogaster Y loops which represent huge, several megabases long, single transcription units. The Y loops provide a particularly amenable model system for transcriptionally active chromatin. We find that, although these transcribed loops are decondensed they are not organised as extended 10nm fibres, but rather they largely consist of chains of nucleosome clusters. The average width of each cluster is around 50nm. We find that foci of active RNA polymerase are generally located off the main fibre axis on the periphery of the nucleosome clusters. Foci of RNA polymerase and nascent transcripts are distributed around the Y loops rather than being clustered in individual transcription factories. However, as the RNA polymerase foci are considerably less prevalent than the nucleosome clusters, the organisation of this active chromatin into chains of nucleosome clusters is unlikely to be determined by the activity of the polymerases transcribing the Y loops. These results provide a foundation for understanding the topological relationship between chromatin and the process of gene transcription.
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Affiliation(s)
- Madeleine L. Ball
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Site, Cambridge, United Kingdom
| | - Stefan A. Koestler
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Site, Cambridge, United Kingdom
| | - Leila Muresan
- Cambridge Advanced Imaging Centre, University of Cambridge, Downing Site, Cambridge, United Kingdom
| | - Sohaib Abdul Rehman
- Cambridge Advanced Imaging Centre, University of Cambridge, Downing Site, Cambridge, United Kingdom
| | - Kevin O’Holleran
- Cambridge Advanced Imaging Centre, University of Cambridge, Downing Site, Cambridge, United Kingdom
| | - Robert White
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Site, Cambridge, United Kingdom
- * E-mail:
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11
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Abstract
In animals, the sequences for controlling gene expression do not concentrate just at the transcription start site of genes, but are frequently thousands to millions of base pairs distal to it. The interaction of these sequences with one another and their transcription start sites is regulated by factors that shape the three-dimensional (3D) organization of the genome within the nucleus. Over the past decade, indirect tools exploiting high-throughput DNA sequencing have helped to map this 3D organization, have identified multiple key regulators of its structure and, in the process, have substantially reshaped our view of how 3D genome architecture regulates transcription. Now, new tools for high-throughput super-resolution imaging of chromatin have directly visualized the 3D chromatin organization, settling some debates left unresolved by earlier indirect methods, challenging some earlier models of regulatory specificity and creating hypotheses about the role of chromatin structure in transcriptional regulation.
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12
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Shaban HA. Nucleus-wide analysis of coherent RNA pol II movement in the context of chromatin dynamics in living cancer cells. Nucleus 2022; 13:313-318. [PMID: 36512483 PMCID: PMC9754109 DOI: 10.1080/19491034.2022.2157133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Activation of transcription results in coordinated movement of chromatin over a range of micrometers. To investigate how transcriptional regulation affects the mobility of RNA Pol II molecules and whether this movement response depends on the coordinated movement of chromatin, we used our Dense Flow reConstruction and Correlation (DFCC) method. Using DFCC, we studies the nucleus-wide coherent movements of RNA Pol II in the context of DNA in humancancer cells. This study showed the dependance of coherent movements of RNA Pol II molecules (above 1 µm) on transcriptional activity. Here, we share the dataset of this study, includes nucleus-wide live imaging and analysis of DNA and RNA polymerase II in different transcription states, and the code for teh analysis. Our dataset may provide researchers interested in the long-range organization of chromatin in living cell images with the ability to link the structural genomic compartment to dynamic information. .
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Affiliation(s)
- Haitham A. Shaban
- Agora Cancer Research Center, Lausanne, Switzerland,Precision Oncology Center, Department of Oncology, Lausanne University Hospital, Lausanne, Switzerland,Spectroscopy Department, Physics Division, National Research Centre, Cairo, Egypt,CONTACT Haitham A. Shaban Precision Oncology Center, Department of Oncology, Lausanne University Hospital, Lausanne1005, Switzerland
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13
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Nollmann M, Bennabi I, Götz M, Gregor T. The Impact of Space and Time on the Functional Output of the Genome. Cold Spring Harb Perspect Biol 2022; 14:a040378. [PMID: 34230036 PMCID: PMC8733053 DOI: 10.1101/cshperspect.a040378] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Over the past two decades, it has become clear that the multiscale spatial and temporal organization of the genome has important implications for nuclear function. This review centers on insights gained from recent advances in light microscopy on our understanding of transcription. We discuss spatial and temporal aspects that shape nuclear order and their consequences on regulatory components, focusing on genomic scales most relevant to function. The emerging picture is that spatiotemporal constraints increase the complexity in transcriptional regulation, highlighting new challenges, such as uncertainty about how information travels from molecular factors through the genome and space to generate a functional output.
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Affiliation(s)
- Marcelo Nollmann
- Centre de Biologie Structurale, CNRS UMR5048, INSERM U1054, Univ Montpellier, 34090 Montpellier, France
| | - Isma Bennabi
- Department of Stem Cell and Developmental Biology, CNRS UMR3738, Institut Pasteur, 75015 Paris, France
| | - Markus Götz
- Centre de Biologie Structurale, CNRS UMR5048, INSERM U1054, Univ Montpellier, 34090 Montpellier, France
| | - Thomas Gregor
- Department of Stem Cell and Developmental Biology, CNRS UMR3738, Institut Pasteur, 75015 Paris, France
- Joseph Henry Laboratory of Physics & Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
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14
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Freeman BC. Genome Organization and Dynamics Specialty Grand Challenge. Front Mol Biosci 2022; 8:818707. [PMID: 35036413 PMCID: PMC8758561 DOI: 10.3389/fmolb.2021.818707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 12/06/2021] [Indexed: 11/29/2022] Open
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15
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Spatial organization of chromosomes leads to heterogeneous chromatin motion and drives the liquid- or gel-like dynamical behavior of chromatin. Genome Res 2021; 32:28-43. [PMID: 34963660 PMCID: PMC8744683 DOI: 10.1101/gr.275827.121] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 12/02/2021] [Indexed: 11/25/2022]
Abstract
Chromosome organization and dynamics are involved in regulating many fundamental processes such as gene transcription and DNA repair. Experiments unveiled that chromatin motion is highly heterogeneous inside cell nuclei, ranging from a liquid-like, mobile state to a gel-like, rigid regime. Using polymer modeling, we investigate how these different physical states and dynamical heterogeneities may emerge from the same structural mechanisms. We found that the formation of topologically associating domains (TADs) is a key driver of chromatin motion heterogeneity. In particular, we showed that the local degree of compaction of the TAD regulates the transition from a weakly compact, fluid state of chromatin to a more compact, gel state exhibiting anomalous diffusion and coherent motion. Our work provides a comprehensive study of chromosome dynamics and a unified view of chromatin motion enabling interpretation of the wide variety of dynamical behaviors observed experimentally across different biological conditions, suggesting that the "liquid" or "solid" state of chromatin are in fact two sides of the same coin.
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Timsit Y, Grégoire SP. Towards the Idea of Molecular Brains. Int J Mol Sci 2021; 22:ijms222111868. [PMID: 34769300 PMCID: PMC8584932 DOI: 10.3390/ijms222111868] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/24/2021] [Accepted: 10/28/2021] [Indexed: 02/06/2023] Open
Abstract
How can single cells without nervous systems perform complex behaviours such as habituation, associative learning and decision making, which are considered the hallmark of animals with a brain? Are there molecular systems that underlie cognitive properties equivalent to those of the brain? This review follows the development of the idea of molecular brains from Darwin’s “root brain hypothesis”, through bacterial chemotaxis, to the recent discovery of neuron-like r-protein networks in the ribosome. By combining a structural biology view with a Bayesian brain approach, this review explores the evolutionary labyrinth of information processing systems across scales. Ribosomal protein networks open a window into what were probably the earliest signalling systems to emerge before the radiation of the three kingdoms. While ribosomal networks are characterised by long-lasting interactions between their protein nodes, cell signalling networks are essentially based on transient interactions. As a corollary, while signals propagated in persistent networks may be ephemeral, networks whose interactions are transient constrain signals diffusing into the cytoplasm to be durable in time, such as post-translational modifications of proteins or second messenger synthesis. The duration and nature of the signals, in turn, implies different mechanisms for the integration of multiple signals and decision making. Evolution then reinvented networks with persistent interactions with the development of nervous systems in metazoans. Ribosomal protein networks and simple nervous systems display architectural and functional analogies whose comparison could suggest scale invariance in information processing. At the molecular level, the significant complexification of eukaryotic ribosomal protein networks is associated with a burst in the acquisition of new conserved aromatic amino acids. Knowing that aromatic residues play a critical role in allosteric receptors and channels, this observation suggests a general role of π systems and their interactions with charged amino acids in multiple signal integration and information processing. We think that these findings may provide the molecular basis for designing future computers with organic processors.
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Affiliation(s)
- Youri Timsit
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UM110, 13288 Marseille, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara GOSEE, 3 rue Michel-Ange, 75016 Paris, France
- Correspondence:
| | - Sergeant-Perthuis Grégoire
- Institut de Mathématiques de Jussieu—Paris Rive Gauche (IMJ-PRG), UMR 7586, CNRS-Université Paris Diderot, 75013 Paris, France;
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Pancaldi V. Chromatin Network Analyses: Towards Structure-Function Relationships in Epigenomics. FRONTIERS IN BIOINFORMATICS 2021; 1:742216. [PMID: 36303769 PMCID: PMC9581029 DOI: 10.3389/fbinf.2021.742216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 10/04/2021] [Indexed: 01/16/2023] Open
Abstract
Recent technological advances have allowed us to map chromatin conformation and uncover the genome’s spatial organization of the genome inside the nucleus. These experiments have revealed the complexities of genome folding, characterized by the presence of loops and domains at different scales, which can change across development and in different cell types. There is strong evidence for a relationship between the topological properties of chromatin contacts and cellular phenotype. Chromatin can be represented as a network, in which genomic fragments are the nodes and connections represent experimentally observed spatial proximity of two genomically distant regions in a specific cell type or biological condition. With this approach we can consider a variety of chromatin features in association with the 3D structure, investigating how nuclear chromatin organization can be related to gene regulation, replication, malignancy, phenotypic variability and plasticity. We briefly review the results obtained on genome architecture through network theoretic approaches. As previously observed in protein-protein interaction networks and many types of non-biological networks, external conditions could shape network topology through a yet unidentified structure-function relationship. Similar to scientists studying the brain, we are confronted with a duality between a spatially embedded network of physical contacts, a related network of correlation in the dynamics of network nodes and, finally, an abstract definition of function of this network, related to phenotype. We summarise major developments in the study of networks in other fields, which we think can suggest a path towards better understanding how 3D genome configuration can impact biological function and adaptation to the environment.
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Affiliation(s)
- Vera Pancaldi
- Centre de Recherches en Cancérologie de Toulouse (CRCT), Institut National de la Santé et de la Recherche Médicale (Inserm) U1037, Centre National de la Recherche Scientifique (CNRS) U5071, Université Paul Sabatier, Toulouse, France
- Barcelona Supercomputing Center, Barcelona, Spain
- *Correspondence: Vera Pancaldi,
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Liu Y, Zhao N, Kanemaki MT, Yamamoto Y, Sadamura Y, Ito Y, Tokunaga M, Stasevich TJ, Kimura H. Visualizing looping of two endogenous genomic loci using synthetic zinc-finger proteins with anti-FLAG and anti-HA frankenbodies in living cells. Genes Cells 2021; 26:905-926. [PMID: 34465007 PMCID: PMC8893316 DOI: 10.1111/gtc.12893] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 08/25/2021] [Accepted: 08/25/2021] [Indexed: 12/17/2022]
Abstract
In eukaryotic nuclei, chromatin loops mediated through cohesin are critical structures that regulate gene expression and DNA replication. Here, we demonstrate a new method to see endogenous genomic loci using synthetic zinc-finger proteins harboring repeat epitope tags (ZF probes) for signal amplification via binding of tag-specific intracellular antibodies, or frankenbodies, fused with fluorescent proteins. We achieve this in two steps: First, we develop an anti-FLAG frankenbody that can bind FLAG-tagged proteins in diverse live-cell environments. The anti-FLAG frankenbody complements the anti-HA frankenbody, enabling two-color signal amplification from FLAG- and HA-tagged proteins. Second, we develop a pair of cell-permeable ZF probes that specifically bind two endogenous chromatin loci predicted to be involved in chromatin looping. By coupling our anti-FLAG and anti-HA frankenbodies with FLAG- and HA-tagged ZF probes, we simultaneously see the dynamics of the two loci in single living cells. This shows a close association between the two loci in the majority of cells, but the loci markedly separate from the triggered degradation of the cohesin subunit RAD21. Our ability to image two endogenous genomic loci simultaneously in single living cells provides a proof of principle that ZF probes coupled with frankenbodies are useful new tools for exploring genome dynamics in multiple colors.
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Affiliation(s)
- Yang Liu
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Ning Zhao
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Masato T Kanemaki
- Department of Chromosome Science, National Institute of Genetics, Research Organization of Information and Systems, Mishima, Japan.,Department of Genetics, SOKENDAI, Mishima, Japan
| | - Yotaro Yamamoto
- Life Science Research Laboratories, Fujifilm Wako Pure Chemical, Amagasaki, Japan
| | - Yoshifusa Sadamura
- Life Science Research Laboratories, Fujifilm Wako Pure Chemical, Amagasaki, Japan
| | - Yuma Ito
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Makio Tokunaga
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Timothy J Stasevich
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA.,Cell Biology Center and World Research Hub Initiative, Tokyo Institute of Technology, Yokohama, Japan
| | - Hiroshi Kimura
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan.,Cell Biology Center and World Research Hub Initiative, Tokyo Institute of Technology, Yokohama, Japan
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Baroux C. Three-dimensional genome organization in epigenetic regulations: cause or consequence? CURRENT OPINION IN PLANT BIOLOGY 2021; 61:102031. [PMID: 33819713 DOI: 10.1016/j.pbi.2021.102031] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 02/09/2021] [Accepted: 02/15/2021] [Indexed: 06/12/2023]
Abstract
The evolution of the nucleus is an evolutionary milestone. By enabling genome compartmentalization, it contributes to the fine-tuning of genome functions. The genome is partitioned into functional domains differing in spatial positioning and topological folding at different scales. The rise of '3D Genomics' embracing experimental, theoretical, and modeling approaches allowed the proposal of a multiscale model of the eukaryotic genome, capturing its organizing principles and functionalities. In these efforts, resolving causality remains an important objective. Are positioning and folding the cause or consequence of functional states? This minireview presents emerging answers to this question, borrowing examples from recent studies of the three-dimensional genome in both plants and animals.
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Affiliation(s)
- Célia Baroux
- Department of Plant and Microbial Biology, Zürich-Basel Plant Science Center, University of Zürich, Switzerland.
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