1
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Dong P, Zhang S, Gandin V, Xie L, Wang L, Lemire AL, Li W, Otsuna H, Kawase T, Lander AD, Chang HY, Liu ZJ. Cohesin prevents cross-domain gene coactivation. Nat Genet 2024:10.1038/s41588-024-01852-1. [PMID: 39048795 DOI: 10.1038/s41588-024-01852-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 06/27/2024] [Indexed: 07/27/2024]
Abstract
The contrast between the disruption of genome topology after cohesin loss and the lack of downstream gene expression changes instigates intense debates regarding the structure-function relationship between genome and gene regulation. Here, by analyzing transcriptome and chromatin accessibility at the single-cell level, we discover that, instead of dictating population-wide gene expression levels, cohesin supplies a general function to neutralize stochastic coexpression tendencies of cis-linked genes in single cells. Notably, cohesin loss induces widespread gene coactivation and chromatin co-opening tens of million bases apart in cis. Spatial genome and protein imaging reveals that cohesin prevents gene co-bursting along the chromosome and blocks spatial mixing of transcriptional hubs. Single-molecule imaging shows that cohesin confines the exploration of diverse enhancer and core promoter binding transcriptional regulators. Together, these results support that cohesin arranges nuclear topology to control gene coexpression in single cells.
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Affiliation(s)
- Peng Dong
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
| | - Shu Zhang
- Center for Personal Dynamic Regulomes and Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Valentina Gandin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Liangqi Xie
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Cancer Biology and Infection Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Lihua Wang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Andrew L Lemire
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Wenhong Li
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Hideo Otsuna
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Takashi Kawase
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Arthur D Lander
- Department of Developmental and Cell Biology, Center for Complex Biological Systems, University of California, Irvine, CA, USA
| | - Howard Y Chang
- Center for Personal Dynamic Regulomes and Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Zhe J Liu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
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2
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Presman DM, Benítez B, Lafuente AL, Vázquez Lareu A. Chromatin structure and dynamics: one nucleosome at a time. Histochem Cell Biol 2024; 162:79-90. [PMID: 38607419 DOI: 10.1007/s00418-024-02281-1] [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] [Accepted: 03/19/2024] [Indexed: 04/13/2024]
Abstract
Eukaryotic genomes store information on many levels, including their linear DNA sequence, the posttranslational modifications of its constituents (epigenetic modifications), and its three-dimensional folding. Understanding how this information is stored and read requires multidisciplinary collaborations from many branches of science beyond biology, including physics, chemistry, and computer science. Concurrent recent developments in all these areas have enabled researchers to image the genome with unprecedented spatial and temporal resolution. In this review, we focus on what single-molecule imaging and tracking of individual proteins in live cells have taught us about chromatin structure and dynamics. Starting with the basics of single-molecule tracking (SMT), we describe some advantages over in situ imaging techniques and its current limitations. Next, we focus on single-nucleosome studies and what they have added to our current understanding of the relationship between chromatin dynamics and transcription. In celebration of Robert Feulgen's ground-breaking discovery that allowed us to start seeing the genome, we discuss current models of chromatin structure and future challenges ahead.
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Affiliation(s)
- Diego M Presman
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Facultad de Ciencias Exactas y Naturales, CONICET-Universidad de Buenos Aires, C1428EGA, Buenos Aires, Argentina.
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C1428EGA, Buenos Aires, Argentina.
| | - Belén Benítez
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Facultad de Ciencias Exactas y Naturales, CONICET-Universidad de Buenos Aires, C1428EGA, Buenos Aires, Argentina
- Instituto de Química Biológica (IQUIBICEN), Facultad de Ciencias Exactas y Naturales, CONICET-Universidad de Buenos Aires, C1428EGA, Buenos Aires, Argentina
| | - Agustina L Lafuente
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Facultad de Ciencias Exactas y Naturales, CONICET-Universidad de Buenos Aires, C1428EGA, Buenos Aires, Argentina
| | - Alejo Vázquez Lareu
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Facultad de Ciencias Exactas y Naturales, CONICET-Universidad de Buenos Aires, C1428EGA, Buenos Aires, Argentina
- Instituto de Química Biológica (IQUIBICEN), Facultad de Ciencias Exactas y Naturales, CONICET-Universidad de Buenos Aires, C1428EGA, Buenos Aires, Argentina
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3
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Semeigazin A, Iida S, Minami K, Tamura S, Ide S, Higashi K, Toyoda A, Kurokawa K, Maeshima K. Behaviors of nucleosomes with mutant histone H4s in euchromatic domains of living human cells. Histochem Cell Biol 2024; 162:23-40. [PMID: 38743310 DOI: 10.1007/s00418-024-02293-x] [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] [Accepted: 04/21/2024] [Indexed: 05/16/2024]
Abstract
Since Robert Feulgen first stained DNA in the cell, visualizing genome chromatin has been a central issue in cell biology to uncover how chromatin is organized and behaves in the cell. To approach this issue, we have developed single-molecule imaging of nucleosomes, a basic unit of chromatin, to unveil local nucleosome behavior in living cells. In this study, we investigated behaviors of nucleosomes with various histone H4 mutants in living HeLa cells to address the role of H4 tail acetylation, including H4K16Ac and others, which are generally associated with more transcriptionally active chromatin regions. We ectopically expressed wild-type (wt) or mutated H4s (H4K16 point; H4K5,8,12,16 quadruple; and H4 tail deletion) fused with HaloTag in HeLa cells. Cells that expressed wtH4-Halo, H4K16-Halo mutants, and multiple H4-Halo mutants had euchromatin-concentrated distribution. Consistently, the genomic regions of the wtH4-Halo nucleosomes corresponded to Hi-C contact domains (or topologically associating domains, TADs) with active chromatin marks (A-compartment). Utilizing single-nucleosome imaging, we found that none of the H4 deacetylation or acetylation mimicked H4 mutants altered the overall local nucleosome motion. This finding suggests that H4 mutant nucleosomes embedded in the condensed euchromatic domains with excess endogenous H4 nucleosomes cannot cause an observable change in the local motion. Interestingly, H4 with four lysine-to-arginine mutations displayed a substantial freely diffusing fraction in the nucleoplasm, whereas H4 with a truncated N-terminal tail was incorporated in heterochromatic regions as well as euchromatin. Our study indicates the power of single-nucleosome imaging to understand individual histone/nucleosome behavior reflecting chromatin environments in living cells.
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Affiliation(s)
- Adilgazy Semeigazin
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Shiori Iida
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Katsuhiko Minami
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Sachiko Tamura
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Satoru Ide
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Koichi Higashi
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
- Genome Evolution Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Ken Kurokawa
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
- Genome Evolution Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan.
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan.
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4
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Garate X, Gómez-García PA, Merino MF, Angles MC, Zhu C, Castells-García A, Ed-Daoui I, Martin L, Ochiai H, Neguembor MV, Cosma MP. The relationship between nanoscale genome organization and gene expression in mouse embryonic stem cells during pluripotency transition. Nucleic Acids Res 2024:gkae476. [PMID: 38850157 DOI: 10.1093/nar/gkae476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/16/2024] [Accepted: 06/05/2024] [Indexed: 06/10/2024] Open
Abstract
During early development, gene expression is tightly regulated. However, how genome organization controls gene expression during the transition from naïve embryonic stem cells to epiblast stem cells is still poorly understood. Using single-molecule microscopy approaches to reach nanoscale resolution, we show that genome remodeling affects gene transcription during pluripotency transition. Specifically, after exit from the naïve pluripotency state, chromatin becomes less compacted, and the OCT4 transcription factor has lower mobility and is more bound to its cognate sites. In epiblast cells, the active transcription hallmark, H3K9ac, decreases within the Oct4 locus, correlating with reduced accessibility of OCT4 and, in turn, with reduced expression of Oct4 nascent RNAs. Despite the high variability in the distances between active pluripotency genes, distances between Nodal and Oct4 decrease during epiblast specification. In particular, highly expressed Oct4 alleles are closer to nuclear speckles during all stages of the pluripotency transition, while only a distinct group of highly expressed Nodal alleles are in close proximity to Oct4 when associated with a nuclear speckle in epiblast cells. Overall, our results provide new insights into the role of the spatiotemporal genome remodeling during mouse pluripotency transition and its correlation with the expression of key pluripotency genes.
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Affiliation(s)
- Ximena Garate
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Pablo Aurelio Gómez-García
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Manuel Fernández Merino
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Marta Cadevall Angles
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Chenggan Zhu
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Alvaro Castells-García
- Medical Research Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 106 Zhongshan Er Road, Yuexiu district, 510080 Guangzhou, China
| | - Ilyas Ed-Daoui
- Medical Research Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 106 Zhongshan Er Road, Yuexiu district, 510080 Guangzhou, China
| | - Laura Martin
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Hiroshi Ochiai
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-0046, Japan
| | - Maria Victoria Neguembor
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Maria Pia Cosma
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
- Medical Research Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 106 Zhongshan Er Road, Yuexiu district, 510080 Guangzhou, China
- ICREA, Pg. Lluis Companys 23, Barcelona 08010, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
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5
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Stoeber S, Godin H, Xu C, Bai L. Pioneer factors: nature or nurture? Crit Rev Biochem Mol Biol 2024:1-15. [PMID: 38778580 DOI: 10.1080/10409238.2024.2355885] [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: 03/03/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024]
Abstract
Chromatin is densely packed with nucleosomes, which limits the accessibility of many chromatin-associated proteins. Pioneer factors (PFs) are usually viewed as a special group of sequence-specific transcription factors (TFs) that can recognize nucleosome-embedded motifs, invade compact chromatin, and generate open chromatin regions. Through this process, PFs initiate a cascade of events that play key roles in gene regulation and cell differentiation. A current debate in the field is if PFs belong to a unique subset of TFs with intrinsic "pioneering activity", or if all TFs have the potential to function as PFs within certain cellular contexts. There are also different views regarding the key feature(s) that define pioneering activity. In this review, we present evidence from the literature related to these alternative views and discuss how to potentially reconcile them. It is possible that both intrinsic properties, like tight nucleosome binding and structural compatibility, and cellular conditions, like concentration and co-factor availability, are important for PF function.
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Affiliation(s)
- Shane Stoeber
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, USA
| | - Holly Godin
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, USA
| | - Cheng Xu
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, USA
| | - Lu Bai
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, USA
- Department of Physics, The Pennsylvania State University, University Park, PA, USA
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6
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Sood A, Schuette G, Zhang B. Dynamical phase transition in models that couple chromatin folding with histone modifications. Phys Rev E 2024; 109:054411. [PMID: 38907407 DOI: 10.1103/physreve.109.054411] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 04/25/2024] [Indexed: 06/24/2024]
Abstract
Genomic regions can acquire heritable epigenetic states through unique histone modifications, which lead to stable gene expression patterns without altering the underlying DNA sequence. However, the relationship between chromatin conformational dynamics and epigenetic stability is poorly understood. In this paper, we propose kinetic models to investigate the dynamic fluctuations of histone modifications and the spatial interactions between nucleosomes. Our model explicitly incorporates the influence of chemical modifications on the structural stability of chromatin and the contribution of chromatin contacts to the cooperative nature of chemical reactions. Through stochastic simulations and analytical theory, we have discovered distinct steady-state outcomes in different kinetic regimes, resembling a dynamical phase transition. Importantly, we have validated that the emergence of this transition, which occurs on biologically relevant timescales, is robust against variations in model design and parameters. Our findings suggest that the viscoelastic properties of chromatin and the timescale at which it transitions from a gel-like to a liquidlike state significantly impact dynamic processes that occur along the one-dimensional DNA sequence.
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7
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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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8
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Mukherjee A, Fallacaro S, Ratchasanmuang P, Zinski J, Boka A, Shankta K, Mir M. A fine kinetic balance of interactions directs transcription factor hubs to genes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.16.589811. [PMID: 38659757 PMCID: PMC11042322 DOI: 10.1101/2024.04.16.589811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Eukaryotic gene regulation relies on the binding of sequence-specific transcription factors (TFs). TFs bind chromatin transiently yet occupy their target sites by forming high-local concentration microenvironments (hubs and condensates) that increase the frequency of binding events. Despite their ubiquity, such microenvironments have been difficult to study in endogenous contexts due to technical limitations. Here, we overcome these limitations and investigate how hubs drive TF occupancy at their targets. Using a DNA binding perturbation to a hub-forming TF, Zelda, in Drosophila embryos, we find that hub properties, including the stability and frequencies of associations to targets, are key determinants of TF occupancy. Our data suggest that the targeting of these hubs is driven not just by specific DNA motif recognition, but also by a fine-tuned kinetic balance of interactions between TFs and their co-binding partners.
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Affiliation(s)
- Apratim Mukherjee
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
| | - Samantha Fallacaro
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
- Developmental, Stem Cell, and Regenerative Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Puttachai Ratchasanmuang
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
- Howard Hughes Medical Institute, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
| | - Joseph Zinski
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
| | - Alan Boka
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kareena Shankta
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
- Roy and Diana Vagelos Program in Life Sciences and Management, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mustafa Mir
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Center for Computational and Genomic Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
- Howard Hughes Medical Institute, Children’s Hospital of Philadelphia, Philadelphia, PA 19104
- Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
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9
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Otsuka A, Minami K, Higashi K, Kawaguchi A, Tamura S, Ide S, Hendzel MJ, Kurokawa K, Maeshima K. Chromatin organization and behavior in HRAS-transformed mouse fibroblasts. Chromosoma 2024; 133:135-148. [PMID: 38400910 DOI: 10.1007/s00412-024-00817-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 01/24/2024] [Accepted: 02/05/2024] [Indexed: 02/26/2024]
Abstract
In higher eukaryotic cells, a string of nucleosomes, where long genomic DNA is wrapped around core histones, are rather irregularly folded into a number of condensed chromatin domains, which have been revealed by super-resolution imaging and Hi-C technologies. Inside these domains, nucleosomes fluctuate and locally behave like a liquid. The behavior of chromatin may be highly related to DNA transaction activities such as transcription and repair, which are often upregulated in cancer cells. To investigate chromatin behavior in cancer cells and compare those of cancer and non-cancer cells, we focused on oncogenic-HRAS (Gly12Val)-transformed mouse fibroblasts CIRAS-3 cells and their parental 10T1/2 cells. CIRAS-3 cells are tumorigenic and highly metastatic. First, we found that HRAS-induced transformation altered not only chromosome structure, but also nuclear morphology in the cell. Using single-nucleosome imaging/tracking in live cells, we demonstrated that nucleosomes are locally more constrained in CIRAS-3 cells than in 10T1/2 cells. Consistently, heterochromatin marked with H3K27me3 was upregulated in CIRAS-3 cells. Finally, Hi-C analysis showed enriched interactions of the B-B compartment in CIRAS-3 cells, which likely represents transcriptionally inactive chromatin. Increased heterochromatin may play an important role in cell migration, as they have been reported to increase during metastasis. Our study also suggests that single-nucleosome imaging provides new insights into how local chromatin is structured in living cells.
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Affiliation(s)
- Aoi Otsuka
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Katsuhiko Minami
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Koichi Higashi
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
- Genome Evolution Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Akane Kawaguchi
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
- Molecular Life History Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Sachiko Tamura
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Satoru Ide
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
| | - Michael J Hendzel
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Ken Kurokawa
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
- Genome Evolution Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan.
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan.
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10
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Won SJ, Zhang Y, Reinhardt CJ, MacRae NS, DeMeester KE, Njomen E, Hargis LM, Remsberg JR, Melillo B, Cravatt BF, Erb MA. Redirecting the pioneering function of FOXA1 with covalent small molecules. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.21.586158. [PMID: 38562719 PMCID: PMC10983899 DOI: 10.1101/2024.03.21.586158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Pioneer transcription factors (TFs) exhibit a specialized ability to bind to and open closed chromatin, facilitating engagement by other regulatory factors involved in gene activation or repression. Chemical probes are lacking for pioneer TFs, which has hindered their mechanistic investigation in cells. Here, we report the chemical proteomic discovery of electrophilic small molecules that stereoselectively and site-specifically bind the pioneer TF, FOXA1, at a cysteine (C258) within the forkhead DNA-binding domain. We show that these covalent ligands react with FOXA1 in a DNA-dependent manner and rapidly remodel its pioneer activity in prostate cancer cells reflected in redistribution of FOXA1 binding across the genome and directionally correlated changes in chromatin accessibility. Motif analysis supports a mechanism where the covalent ligands relax the canonical DNA binding preference of FOXA1 by strengthening interactions with suboptimal ancillary sequences in predicted proximity to C258. Our findings reveal a striking plasticity underpinning the pioneering function of FOXA1 that can be controlled by small molecules.
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11
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Barral A, Zaret KS. Pioneer factors: roles and their regulation in development. Trends Genet 2024; 40:134-148. [PMID: 37940484 PMCID: PMC10873006 DOI: 10.1016/j.tig.2023.10.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/06/2023] [Accepted: 10/06/2023] [Indexed: 11/10/2023]
Abstract
Pioneer factors are a subclass of transcription factors that can bind and initiate opening of silent chromatin regions. Pioneer factors subsequently regulate lineage-specific genes and enhancers and, thus, activate the zygotic genome after fertilization, guide cell fate transitions during development, and promote various forms of human cancers. As such, pioneer factors are useful in directed cell reprogramming. In this review, we define the structural and functional characteristics of pioneer factors, how they bind and initiate opening of closed chromatin regions, and the consequences for chromatin dynamics and gene expression during cell differentiation. We also discuss emerging mechanisms that modulate pioneer factors during development.
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Affiliation(s)
- Amandine Barral
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Boulevard, Philadelphia, PA 19104, USA
| | - Kenneth S Zaret
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Boulevard, Philadelphia, PA 19104, USA.
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12
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Thakur A, Park K, Cullum R, Fuglerud BM, Khoshnoodi M, Drissler S, Stephan TL, Lotto J, Kim D, Gonzalez FJ, Hoodless PA. HNF4A guides the MLL4 complex to establish and maintain H3K4me1 at gene regulatory elements. Commun Biol 2024; 7:144. [PMID: 38297077 PMCID: PMC10830483 DOI: 10.1038/s42003-024-05835-0] [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: 03/25/2022] [Accepted: 01/18/2024] [Indexed: 02/02/2024] Open
Abstract
Hepatocyte nuclear factor 4A (HNF4A/NR2a1), a transcriptional regulator of hepatocyte identity, controls genes that are crucial for liver functions, primarily through binding to enhancers. In mammalian cells, active and primed enhancers are marked by monomethylation of histone 3 (H3) at lysine 4 (K4) (H3K4me1) in a cell type-specific manner. How this modification is established and maintained at enhancers in connection with transcription factors (TFs) remains unknown. Using analysis of genome-wide histone modifications, TF binding, chromatin accessibility and gene expression, we show that HNF4A is essential for an active chromatin state. Using HNF4A loss and gain of function experiments in vivo and in cell lines in vitro, we show that HNF4A affects H3K4me1, H3K27ac and chromatin accessibility, highlighting its contribution to the establishment and maintenance of a transcriptionally permissive epigenetic state. Mechanistically, HNF4A interacts with the mixed-lineage leukaemia 4 (MLL4) complex facilitating recruitment to HNF4A-bound regions. Our findings indicate that HNF4A enriches H3K4me1, H3K27ac and establishes chromatin opening at transcriptional regulatory regions.
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Affiliation(s)
- Avinash Thakur
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | - Kwangjin Park
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | - Rebecca Cullum
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
| | - Bettina M Fuglerud
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | | | - Sibyl Drissler
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
- Cell and Developmental Biology Program, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | - Tabea L Stephan
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
- Cell and Developmental Biology Program, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | - Jeremy Lotto
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada
- Cell and Developmental Biology Program, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | - Donghwan Kim
- Center of Cancer Research, National Cancer Institute, Bethesda, 2089, USA
| | - Frank J Gonzalez
- Center of Cancer Research, National Cancer Institute, Bethesda, 2089, USA
| | - Pamela A Hoodless
- Terry Fox Laboratory, BC Cancer, Vancouver, V5Z 1L3, Canada.
- Department of Medical Genetics, University of British Columbia, Vancouver, V6T 1Z4, Canada.
- Cell and Developmental Biology Program, University of British Columbia, Vancouver, V6T 1Z4, Canada.
- School of Biomedical Engineering, University of British Columbia, Vancouver, V6T 1Z4, Canada.
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13
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Maeshima K, Iida S, Shimazoe MA, Tamura S, Ide S. Is euchromatin really open in the cell? Trends Cell Biol 2024; 34:7-17. [PMID: 37385880 DOI: 10.1016/j.tcb.2023.05.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 05/16/2023] [Accepted: 05/19/2023] [Indexed: 07/01/2023]
Abstract
Genomic DNA is wrapped around a core histone octamer and forms a nucleosome. In higher eukaryotic cells, strings of nucleosomes are irregularly folded as chromatin domains that act as functional genome units. According to a typical textbook model, chromatin can be categorized into two types, euchromatin and heterochromatin, based on its degree of compaction. Euchromatin is open, while heterochromatin is closed and condensed. However, is euchromatin really open in the cell? New evidence from genomics and advanced imaging studies has revealed that euchromatin consists of condensed liquid-like domains. Condensed chromatin seems to be the default chromatin state in higher eukaryotic cells. We discuss this novel view of euchromatin in the cell and how the revealed organization is relevant to genome functions.
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Affiliation(s)
- Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka 411-8540, Japan.
| | - Shiori Iida
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka 411-8540, Japan
| | - Masa A Shimazoe
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka 411-8540, Japan
| | - Sachiko Tamura
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Satoru Ide
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka 411-8540, Japan
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14
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Bulyk ML, Drouin J, Harrison MM, Taipale J, Zaret KS. Pioneer factors - key regulators of chromatin and gene expression. Nat Rev Genet 2023; 24:809-815. [PMID: 37740118 DOI: 10.1038/s41576-023-00648-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2023] [Indexed: 09/24/2023]
Affiliation(s)
- Martha L Bulyk
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
| | - Jacques Drouin
- Laboratoire de génétique moléculaire, Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada.
- Département de Biochimie, Université de Montréal, Montreal, Quebec, Canada.
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
| | - Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA.
| | - Jussi Taipale
- Department of Biochemistry, University of Cambridge, Cambridge, UK.
- Applied Tumour Genomics Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
| | - Kenneth S Zaret
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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15
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García Fernández F, Huet S, Miné-Hattab J. Multi-Scale Imaging of the Dynamic Organization of Chromatin. Int J Mol Sci 2023; 24:15975. [PMID: 37958958 PMCID: PMC10649806 DOI: 10.3390/ijms242115975] [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: 09/19/2023] [Revised: 10/27/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023] Open
Abstract
Chromatin is now regarded as a heterogeneous and dynamic structure occupying a non-random position within the cell nucleus, where it plays a key role in regulating various functions of the genome. This current view of chromatin has emerged thanks to high spatiotemporal resolution imaging, among other new technologies developed in the last decade. In addition to challenging early assumptions of chromatin being regular and static, high spatiotemporal resolution imaging made it possible to visualize and characterize different chromatin structures such as clutches, domains and compartments. More specifically, super-resolution microscopy facilitates the study of different cellular processes at a nucleosome scale, providing a multi-scale view of chromatin behavior within the nucleus in different environments. In this review, we describe recent imaging techniques to study the dynamic organization of chromatin at high spatiotemporal resolution. We also discuss recent findings, elucidated by these techniques, on the chromatin landscape during different cellular processes, with an emphasis on the DNA damage response.
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Affiliation(s)
- Fabiola García Fernández
- Laboratory of Computational and Quantitative Biology, CNRS, Institut de Biologie Paris-Seine, Sorbonne Université, 75005 Paris, France;
| | - Sébastien Huet
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes)-UMR 6290, BIOSIT-UMS 3480, 35000 Rennes, France;
- Institut Universitaire de France, 75231 Paris, France
| | - Judith Miné-Hattab
- Laboratory of Computational and Quantitative Biology, CNRS, Institut de Biologie Paris-Seine, Sorbonne Université, 75005 Paris, France;
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16
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Mehra D, Puchner EM. Correlative Conventional and Super-resolution Photoactivated Localization Microscopy (PALM) Imaging to Characterize Chromatin Structure and Dynamics in Live Mammalian Cells. Bio Protoc 2023; 13:e4850. [PMID: 37900107 PMCID: PMC10603262 DOI: 10.21769/bioprotoc.4850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/14/2023] [Accepted: 08/15/2023] [Indexed: 10/31/2023] Open
Abstract
A fundamental understanding of gene regulation requires a quantitative characterization of the spatial organization and dynamics of chromatin. The advent of fluorescence super-resolution microscopy techniques such as photoactivated localization microscopy (PALM) presented a breakthrough to visualize structural features with a resolution of ~20 nm in fixed cells. However, until recently the long acquisition time of super-resolution images prevented high-resolution measurements in living cells due to spreading of localizations caused by chromatin motion. Here, we present a step-by step protocol for our recently developed approach for correlatively imaging telomeres with conventional fluorescence and PALM, in order to obtain time-averaged super-resolution images and dynamic parameters in living cells. First, individual single molecule localizations are assigned to a locus as it moves, allowing to discriminate between bound and unbound dCas9 molecules, whose mobilities overlap. By subtracting the telomere trajectory from the localization of bound molecules, the motion blurring is then corrected, and high-resolution structural characterizations can be made. These structural parameters can also be related to local chromatin motion or larger scale domain movement. This protocol therefore improves the ability to analyze the mobility and time-averaged nanoscopic structure of locus-specific chromatin with single-molecule sensitivity.
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Affiliation(s)
- Dushyant Mehra
- School of Physics and Astronomy, University of Minnesota, Twin Cities, MN, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Elias M. Puchner
- School of Physics and Astronomy, University of Minnesota, Twin Cities, MN, USA
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17
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Hou Z, Nightingale F, Zhu Y, MacGregor-Chatwin C, Zhang P. Structure of native chromatin fibres revealed by Cryo-ET in situ. Nat Commun 2023; 14:6324. [PMID: 37816746 PMCID: PMC10564948 DOI: 10.1038/s41467-023-42072-1] [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: 08/26/2023] [Accepted: 09/28/2023] [Indexed: 10/12/2023] Open
Abstract
The structure of chromatin plays pivotal roles in regulating gene transcription, DNA replication and repair, and chromosome segregation. This structure, however, remains elusive. Here, using cryo-FIB and cryo-ET, we delineate the 3D architecture of native chromatin fibres in intact interphase human T-lymphoblasts and determine the in situ structures of nucleosomes in different conformations. These chromatin fibres are not structured as uniform 30 nm one-start or two-start filaments but are composed of relaxed, variable zigzag organizations of nucleosomes connected by straight linker DNA. Nucleosomes with little H1 and linker DNA density are distributed randomly without any spatial preference. This work will inspire future high-resolution investigations on native chromatin structures in situ at both a single-nucleosome level and a population level under many different cellular conditions in health and disease.
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Affiliation(s)
- Zhen Hou
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Frank Nightingale
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Yanan Zhu
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | - Peijun Zhang
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK.
- Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, UK.
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18
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Saxton MN, Morisaki T, Krapf D, Kimura H, Stasevich TJ. Live-cell imaging uncovers the relationship between histone acetylation, transcription initiation, and nucleosome mobility. SCIENCE ADVANCES 2023; 9:eadh4819. [PMID: 37792937 PMCID: PMC10550241 DOI: 10.1126/sciadv.adh4819] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 09/01/2023] [Indexed: 10/06/2023]
Abstract
Histone acetylation and RNA polymerase II phosphorylation are associated with transcriptionally active chromatin, but their spatiotemporal relationship in live cells remains poorly understood. To address this problem, we combine Fab-based labeling of endogenous protein modifications with single-molecule tracking to quantify the dynamics of chromatin enriched with histone H3 lysine-27 acetylation (H3K27ac) and RNA polymerase II serine-5 phosphorylation (RNAP2-Ser5ph). Our analysis reveals that chromatin enriched with these two modifications is generally separate. In these separated sites, we show that the two modifications are inversely correlated with one another on the minutes time scale and that single nucleosomes within each region display distinct and opposing dynamics on the subsecond time scale. While nucleosomes diffuse ~15% faster in chromatin enriched with H3K27ac, they diffuse ~15% slower in chromatin enriched with RNAP2-Ser5ph. These results argue that high levels of H3K27ac and RNAP2-Ser5ph are not often present together at the same place and time, but rather each marks distinct transcriptionally poised or active sites, respectively.
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Affiliation(s)
- Matthew N. Saxton
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Tatsuya Morisaki
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Diego Krapf
- Department of Electrical and Computer Engineering, and School of Biomedical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Hiroshi Kimura
- Cell Biology Center and World Research Hub Initiative, Tokyo Institute of Technology, Yokohama, Japan
- 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
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19
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Soroczynski J, Risca VI. Technological advances in probing 4D genome organization. Curr Opin Cell Biol 2023; 84:102211. [PMID: 37556867 PMCID: PMC10588670 DOI: 10.1016/j.ceb.2023.102211] [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: 04/01/2023] [Revised: 05/13/2023] [Accepted: 06/29/2023] [Indexed: 08/11/2023]
Abstract
The last two decades of work on chromosome conformation in eukaryotic nuclei have revealed a complex and highly regulated hierarchy of architectural features, from self-associating domains and compartmental interactions to locus-specific loops. Recent findings have shown that these structures are dynamic and heterogeneous, with emerging insights into the factors that shape them and implications for the control of transcription and other nuclear processes. Here, we review the latest advances in the DNA sequencing- and microscopy-based technologies for probing these features in space and time (4D) and discuss how they have been combined with complementary approaches such as genetic perturbations, protein and RNA measurements, and modeling to gain mechanistic insights about genome regulation across space and time.
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Affiliation(s)
- Jan Soroczynski
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, 1230 York Ave., Box 176, New York, NY 10065, USA; David Rockefeller Graduate Program in Bioscience, The Rockefeller University, 1230 York Ave., New York, NY 10065, USA
| | - Viviana I Risca
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, 1230 York Ave., Box 176, New York, NY 10065, USA.
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20
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Okamoto K, Fujita H, Okada Y, Shinkai S, Onami S, Abe K, Fujimoto K, Sasaki K, Shioi G, Watanabe TM. Single-molecule tracking of Nanog and Oct4 in living mouse embryonic stem cells uncovers a feedback mechanism of pluripotency maintenance. EMBO J 2023; 42:e112305. [PMID: 37609947 PMCID: PMC10505915 DOI: 10.15252/embj.2022112305] [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: 08/05/2022] [Revised: 06/13/2023] [Accepted: 06/22/2023] [Indexed: 08/24/2023] Open
Abstract
Nanog and Oct4 are core transcription factors that form part of a gene regulatory network to regulate hundreds of target genes for pluripotency maintenance in mouse embryonic stem cells (ESCs). To understand their function in the pluripotency maintenance, we visualised and quantified the dynamics of single molecules of Nanog and Oct4 in a mouse ESCs during pluripotency loss. Interestingly, Nanog interacted longer with its target loci upon reduced expression or at the onset of differentiation, suggesting a feedback mechanism to maintain the pluripotent state. The expression level and interaction time of Nanog and Oct4 correlate with their fluctuation and interaction frequency, respectively, which in turn depend on the ESC differentiation status. The DNA viscoelasticity near the Oct4 target locus remained flexible during differentiation, supporting its role either in chromatin opening or a preferred binding to uncondensed chromatin regions. Based on these results, we propose a new negative feedback mechanism for pluripotency maintenance via the DNA condensation state-dependent interplay of Nanog and Oct4.
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Affiliation(s)
- Kazuko Okamoto
- Laboratory for Comprehensive BioimagingRIKEN Center for Biosystems Dynamics Research (BDR)KobeJapan
- Amphibian Research CenterHiroshima UniversityHiroshimaJapan
| | - Hideaki Fujita
- Department of Stem Cell Biology, Research Institute for Radiation Biology and MedicineHiroshima UniversityHigashi‐HiroshimaJapan
| | - Yasushi Okada
- Laboratory for Cell Polarity RegulationRIKEN Center for Biosystems Dynamics Research (BDR)OsakaJapan
- Department of Cell BiologyGraduate School of Medicine, The University of TokyoTokyoJapan
- Department of PhysicsUniversal Biology Institute (UBI)Graduate School of Science, The University of TokyoTokyoJapan
- International Research Center for Neurointelligence (WPI‐IRCN)Institutes for Advanced Study, The University of TokyoTokyoJapan
| | - Soya Shinkai
- Laboratory for Developmental DynamicsRIKEN Center for Biosystems Dynamics Research (BDR)KobeJapan
- Research Center for the Mathematics on Chromatin Live Dynamics (RcMcD)Hiroshima UniversityHiroshimaJapan
| | - Shuichi Onami
- Laboratory for Developmental DynamicsRIKEN Center for Biosystems Dynamics Research (BDR)KobeJapan
| | - Kuniya Abe
- Technology and Development Team for Mammalian Genome DynamicsRIKEN BioResource Research Center (BRC)TsukubaJapan
| | - Kenta Fujimoto
- Department of Stem Cell Biology, Research Institute for Radiation Biology and MedicineHiroshima UniversityHigashi‐HiroshimaJapan
| | - Kensuke Sasaki
- Laboratory for Comprehensive BioimagingRIKEN Center for Biosystems Dynamics Research (BDR)KobeJapan
| | - Go Shioi
- Laboratory for Comprehensive BioimagingRIKEN Center for Biosystems Dynamics Research (BDR)KobeJapan
| | - Tomonobu M Watanabe
- Laboratory for Comprehensive BioimagingRIKEN Center for Biosystems Dynamics Research (BDR)KobeJapan
- Department of Stem Cell Biology, Research Institute for Radiation Biology and MedicineHiroshima UniversityHigashi‐HiroshimaJapan
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21
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Felske T, Tocco C, Péron S, Harb K, Alfano C, Galante C, Berninger B, Studer M. Lmo4 synergizes with Fezf2 to promote direct in vivo reprogramming of upper layer cortical neurons and cortical glia towards deep-layer neuron identities. PLoS Biol 2023; 21:e3002237. [PMID: 37552690 PMCID: PMC10409279 DOI: 10.1371/journal.pbio.3002237] [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: 12/20/2022] [Accepted: 07/06/2023] [Indexed: 08/10/2023] Open
Abstract
In vivo direct neuronal reprogramming relies on the implementation of an exogenous transcriptional program allowing to achieve conversion of a particular neuronal or glial cell type towards a new identity. The transcription factor (TF) Fezf2 is known for its role in neuronal subtype specification of deep-layer (DL) subcortical projection neurons. High ectopic Fezf2 expression in mice can convert both upper-layer (UL) and striatal projection neurons into a corticofugal fate, even if at low efficiency. In this study, we show that Fezf2 synergizes with the nuclear co-adaptor Lmo4 to further enhance reprogramming of UL cortical pyramidal neurons into DL corticofugal neurons, at both embryonic and early postnatal stages. Reprogrammed neurons express DL molecular markers and project toward subcerebral targets, including thalamus, cerebral peduncle (CP), and spinal cord (SC). We also show that co-expression of Fezf2 with the reprogramming factors Neurog2 and Bcl2 in early postnatal mouse glia promotes glia-to-neuron conversion with partial hallmarks of DL neurons and with Lmo4 promoting further morphological complexity. These data support a novel role for Lmo4 in synergizing with Fezf2 during direct lineage conversion in vivo.
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Affiliation(s)
| | - Chiara Tocco
- Université Côte d’Azur, CNRS, Inserm, iBV, Nice, France
| | - Sophie Péron
- Research Group “Adult Neurogenesis and Cellular Reprogramming”, Institute of Physiological Chemistry, University Medical Center Johannes Gutenberg University, Mainz, Germany
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom
| | - Kawssar Harb
- Université Côte d’Azur, CNRS, Inserm, iBV, Nice, France
| | | | - Chiara Galante
- Research Group “Adult Neurogenesis and Cellular Reprogramming”, Institute of Physiological Chemistry, University Medical Center Johannes Gutenberg University, Mainz, Germany
| | - Benedikt Berninger
- Research Group “Adult Neurogenesis and Cellular Reprogramming”, Institute of Physiological Chemistry, University Medical Center Johannes Gutenberg University, Mainz, Germany
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom
- Focus Program Translational Neuroscience, Johannes Gutenberg University, Mainz, Germany
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22
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Lerner J, Katznelson A, Zhang J, Zaret KS. Different chromatin-scanning modes lead to targeting of compacted chromatin by pioneer factors FOXA1 and SOX2. Cell Rep 2023; 42:112748. [PMID: 37405916 PMCID: PMC10529229 DOI: 10.1016/j.celrep.2023.112748] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 04/20/2023] [Accepted: 06/19/2023] [Indexed: 07/07/2023] Open
Abstract
Pioneer transcription factors interact with nucleosomes to scan silent, compact chromatin, enabling cooperative events that modulate gene activity. While at a subset of sites pioneer factors access chromatin by assisted loading with other transcription factors, the nucleosome-binding properties of pioneer factors enable them to initiate zygotic genome activation, embryonic development, and cellular reprogramming. To better understand nucleosome targeting in vivo, we assess whether pioneer factors FoxA1 and Sox2 target stable or unstable nucleosomes and find that they target DNase-resistant, stable nucleosomes, whereas HNF4A, a non-nucleosome binding factor, targets open, DNase-sensitive chromatin. Despite FOXA1 and SOX2 targeting similar proportions of DNase-resistant chromatin, using single-molecule tracking, we find that FOXA1 uses lower nucleoplasmic diffusion and longer residence times while SOX2 uses higher nucleoplasmic diffusion and shorter residence times to scan compact chromatin, while HNF4 scans compact chromatin much less efficiently. Thus, pioneer factors target compact chromatin through distinct processes.
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Affiliation(s)
- Jonathan Lerner
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Andrew Katznelson
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Jingchao Zhang
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Kenneth S Zaret
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA.
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23
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Torcal Garcia G, Kowenz-Leutz E, Tian TV, Klonizakis A, Lerner J, De Andres-Aguayo L, Sapozhnikova V, Berenguer C, Carmona MP, Casadesus MV, Bulteau R, Francesconi M, Peiro S, Mertins P, Zaret K, Leutz A, Graf T. Carm1-arginine methylation of the transcription factor C/EBPα regulates transdifferentiation velocity. eLife 2023; 12:e83951. [PMID: 37365888 PMCID: PMC10299824 DOI: 10.7554/elife.83951] [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: 10/05/2022] [Accepted: 05/30/2023] [Indexed: 06/28/2023] Open
Abstract
Here, we describe how the speed of C/EBPα-induced B cell to macrophage transdifferentiation (BMT) can be regulated, using both mouse and human models. The identification of a mutant of C/EBPα (C/EBPαR35A) that greatly accelerates BMT helped to illuminate the mechanism. Thus, incoming C/EBPα binds to PU.1, an obligate partner expressed in B cells, leading to the release of PU.1 from B cell enhancers, chromatin closing and silencing of the B cell program. Released PU.1 redistributes to macrophage enhancers newly occupied by C/EBPα, causing chromatin opening and activation of macrophage genes. All these steps are accelerated by C/EBPαR35A, initiated by its increased affinity for PU.1. Wild-type C/EBPα is methylated by Carm1 at arginine 35 and the enzyme's perturbations modulate BMT velocity as predicted from the observations with the mutant. Increasing the proportion of unmethylated C/EBPα in granulocyte/macrophage progenitors by inhibiting Carm1 biases the cell's differentiation toward macrophages, suggesting that cell fate decision velocity and lineage directionality are closely linked processes.
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Affiliation(s)
- Guillem Torcal Garcia
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | | | - Tian V Tian
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
- Vall d’Hebron Institute of Oncology (VHIO)BarcelonaSpain
| | - Antonis Klonizakis
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Jonathan Lerner
- Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Luisa De Andres-Aguayo
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Valeriia Sapozhnikova
- Max Delbrück Center for Molecular Medicine in the Helmholtz AssociationBerlinGermany
| | - Clara Berenguer
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Marcos Plana Carmona
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Maria Vila Casadesus
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
- Vall d’Hebron Institute of Oncology (VHIO)BarcelonaSpain
| | - Romain Bulteau
- Laboratorie de Biologie et Modélisation de la Cellule, Université de LyonLyonFrance
| | - Mirko Francesconi
- Laboratorie de Biologie et Modélisation de la Cellule, Université de LyonLyonFrance
| | - Sandra Peiro
- Vall d’Hebron Institute of Oncology (VHIO)BarcelonaSpain
| | - Philipp Mertins
- Max Delbrück Center for Molecular Medicine in the Helmholtz AssociationBerlinGermany
| | - Kenneth Zaret
- Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Achim Leutz
- Max Delbrück Center for Molecular Medicine in the Helmholtz AssociationBerlinGermany
| | - Thomas Graf
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
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24
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Wagh K, Stavreva DA, Jensen RAM, Paakinaho V, Fettweis G, Schiltz RL, Wüstner D, Mandrup S, Presman DM, Upadhyaya A, Hager GL. Dynamic switching of transcriptional regulators between two distinct low-mobility chromatin states. SCIENCE ADVANCES 2023; 9:eade1122. [PMID: 37315128 PMCID: PMC10954219 DOI: 10.1126/sciadv.ade1122] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 05/10/2023] [Indexed: 06/16/2023]
Abstract
How chromatin dynamics relate to transcriptional activity remains poorly understood. Using single-molecule tracking, coupled with machine learning, we show that histone H2B and multiple chromatin-bound transcriptional regulators display two distinct low-mobility states. Ligand activation results in a marked increase in the propensity of steroid receptors to bind in the lowest-mobility state. Mutational analysis revealed that interactions with chromatin in the lowest-mobility state require an intact DNA binding domain and oligomerization domains. These states are not spatially separated as previously believed, but individual H2B and bound-TF molecules can dynamically switch between them on time scales of seconds. Single bound-TF molecules with different mobilities exhibit different dwell time distributions, suggesting that the mobility of TFs is intimately coupled with their binding dynamics. Together, our results identify two unique and distinct low-mobility states that appear to represent common pathways for transcription activation in mammalian cells.
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Affiliation(s)
- Kaustubh Wagh
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
- Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - Diana A. Stavreva
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Rikke A. M. Jensen
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Ville Paakinaho
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
- Institute of Biomedicine, University of Eastern Finland, Kuopio, P.O. Box 1627, 70211 Kuopio, Finland
| | - Gregory Fettweis
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - R. Louis Schiltz
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Susanne Mandrup
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Diego M. Presman
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires C1428EGA, Argentina
| | - Arpita Upadhyaya
- Department of Physics, University of Maryland, College Park, MD 20742, USA
- Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
| | - Gordon L. Hager
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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25
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McCarthy RL, Zhang J, Zaret KS. Diverse heterochromatin states restricting cell identity and reprogramming. Trends Biochem Sci 2023; 48:513-526. [PMID: 36990958 PMCID: PMC10182259 DOI: 10.1016/j.tibs.2023.02.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 02/16/2023] [Accepted: 02/24/2023] [Indexed: 03/29/2023]
Abstract
Heterochromatin is defined as a chromosomal domain harboring repressive H3K9me2/3 or H3K27me3 histone modifications and relevant factors that physically compact the chromatin. Heterochromatin can restrict where transcription factors bind, providing a barrier to gene activation and changes in cell identity. While heterochromatin thus helps maintain cell differentiation, it presents a barrier to overcome during efforts to reprogram cells for biomedical purposes. Recent findings have revealed complexity in the composition and regulation of heterochromatin, and shown that transiently disrupting the machinery of heterochromatin can enhance reprogramming. Here, we discuss how heterochromatin is established and maintained during development, and how our growing understanding of the mechanisms regulating H3K9me3 heterochromatin can be leveraged to improve our ability to direct changes in cell identity.
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Affiliation(s)
- Ryan L McCarthy
- Institute for Regenerative Medicine, Penn Epigenetics Institute, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jingchao Zhang
- Institute for Regenerative Medicine, Penn Epigenetics Institute, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kenneth S Zaret
- Institute for Regenerative Medicine, Penn Epigenetics Institute, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Abstract
Super-resolution fluorescence microscopy allows the investigation of cellular structures at nanoscale resolution using light. Current developments in super-resolution microscopy have focused on reliable quantification of the underlying biological data. In this review, we first describe the basic principles of super-resolution microscopy techniques such as stimulated emission depletion (STED) microscopy and single-molecule localization microscopy (SMLM), and then give a broad overview of methodological developments to quantify super-resolution data, particularly those geared toward SMLM data. We cover commonly used techniques such as spatial point pattern analysis, colocalization, and protein copy number quantification but also describe more advanced techniques such as structural modeling, single-particle tracking, and biosensing. Finally, we provide an outlook on exciting new research directions to which quantitative super-resolution microscopy might be applied.
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Affiliation(s)
- Siewert Hugelier
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; , ,
| | - P L Colosi
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; , ,
| | - Melike Lakadamyali
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; , ,
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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27
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Cosma MP, Neguembor MV. The magic of unraveling genome architecture and function. Cell Rep 2023; 42:112361. [PMID: 37059093 DOI: 10.1016/j.celrep.2023.112361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/20/2023] [Accepted: 03/22/2023] [Indexed: 04/16/2023] Open
Abstract
Over the last decades, technological breakthroughs in super-resolution microscopy have allowed us to reach molecular resolution and design experiments of unprecedented complexity. Investigating how chromatin is folded in 3D, from the nucleosome level up to the entire genome, is becoming possible by "magic" (imaging genomic), i.e., the combination of imaging and genomic approaches. This offers endless opportunities to delve into the relationship between genome structure and function. Here, we review recently achieved objectives and the conceptual and technical challenges the field of genome architecture is currently undertaking. We discuss what we have learned so far and where we are heading. We elucidate how the different super-resolution microscopy approaches and, more specifically, live-cell imaging have contributed to the understanding of genome folding. Moreover, we discuss how future technical developments could address remaining open questions.
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Affiliation(s)
- Maria Pia Cosma
- Medical Research Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 106 Zhongshan Er Road, Yuexiu District, 510080 Guangzhou, China; Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Dr Aiguader 88, 08003 Barcelona, Spain; ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain.
| | - Maria Victoria Neguembor
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain.
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28
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Single-molecule tracking (SMT): a window into live-cell transcription biochemistry. Biochem Soc Trans 2023; 51:557-569. [PMID: 36876879 DOI: 10.1042/bst20221242] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 03/07/2023]
Abstract
How molecules interact governs how they move. Single-molecule tracking (SMT) thus provides a unique window into the dynamic interactions of biomolecules within live cells. Using transcription regulation as a case study, we describe how SMT works, what it can tell us about molecular biology, and how it has changed our perspective on the inner workings of the nucleus. We also describe what SMT cannot yet tell us and how new technical advances seek to overcome its limitations. This ongoing progress will be imperative to address outstanding questions about how dynamic molecular machines function in live cells.
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29
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Zaret KS. Two ways to skin a new cell fate. Dev Cell 2023; 58:1-2. [PMID: 36626868 PMCID: PMC9979843 DOI: 10.1016/j.devcel.2022.12.002] [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] [Indexed: 01/11/2023]
Abstract
To induce cell fate changes, do transcription factors engage open domains of chromatin or elicit chromatin opening in a pioneering fashion? In this issue of Developmental Cell, Delás et al. show that the same sonic hedgehog (Shh) inducing signal can yield different neural tube fates by either modality.
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Affiliation(s)
- Kenneth S Zaret
- Institute for Regenerative Medicine, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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30
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Zaret KS. G&D vignettes. Genes Dev 2023; 37:63-68. [PMID: 37061958 PMCID: PMC10046443 DOI: 10.1101/gad.350444.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
Affiliation(s)
- Kenneth S Zaret
- Institute for Regenerative Medicine, Epigenetics Institute, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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31
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Mansisidor AR, Risca VI. Chromatin accessibility: methods, mechanisms, and biological insights. Nucleus 2022; 13:236-276. [PMID: 36404679 PMCID: PMC9683059 DOI: 10.1080/19491034.2022.2143106] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/23/2022] [Accepted: 10/30/2022] [Indexed: 11/22/2022] Open
Abstract
Access to DNA is a prerequisite to the execution of essential cellular processes that include transcription, replication, chromosomal segregation, and DNA repair. How the proteins that regulate these processes function in the context of chromatin and its dynamic architectures is an intensive field of study. Over the past decade, genome-wide assays and new imaging approaches have enabled a greater understanding of how access to the genome is regulated by nucleosomes and associated proteins. Additional mechanisms that may control DNA accessibility in vivo include chromatin compaction and phase separation - processes that are beginning to be understood. Here, we review the ongoing development of accessibility measurements, we summarize the different molecular and structural mechanisms that shape the accessibility landscape, and we detail the many important biological functions that are linked to chromatin accessibility.
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Affiliation(s)
- Andrés R. Mansisidor
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
| | - Viviana I. Risca
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
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32
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Abstract
Genomic DNA is organized three-dimensionally in the nucleus as chromatin. Recent accumulating evidence has demonstrated that chromatin organizes into numerous dynamic domains in higher eukaryotic cells, which act as functional units of the genome. These compacted domains facilitate DNA replication and gene regulation. Undamaged chromatin is critical for healthy cells to function and divide. However, the cellular genome is constantly threatened by many sources of DNA damage (e.g., radiation). How do cells maintain their genome integrity when subjected to DNA damage? This chapter describes how the compact state of chromatin safeguards the genome from radiation damage and chemical attacks. Together with recent genomics data, our finding suggests that DNA compaction, such as chromatin domain formation, plays a critical role in maintaining genome integrity. But does the formation of such domains limit DNA accessibility inside the domain and hinder the recruitment of repair machinery to the damaged site(s) during DNA repair? To approach this issue, we first describe a sensitive imaging method to detect changes in chromatin states in living cells (single-nucleosome imaging/tracking). We then use this method to explain how cells can overcome potential recruiting difficulties; cells can decompact chromatin domains following DNA damage and temporarily increase chromatin motion (∼DNA accessibility) to perform efficient DNA repair. We also speculate on how chromatin compaction affects DNA damage-resistance in the clinical setting.
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Affiliation(s)
- Katsuhiko Minami
- Genome Dynamics Laboratory, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Shizuoka, Japan; Department of Genetics, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Shizuoka, Japan
| | - Shiori Iida
- Genome Dynamics Laboratory, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Shizuoka, Japan; Department of Genetics, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Shizuoka, Japan
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Shizuoka, Japan; Department of Genetics, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Shizuoka, Japan.
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33
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Abstract
Virtually all cell types have the same DNA, yet each type exhibits its own cell-specific pattern of gene expression. During the brief period of mitosis, the chromosomes exhibit changes in protein composition and modifications, a marked condensation, and a consequent reduction in transcription. Yet as cells exit mitosis, they reactivate their cell-specific programs with high fidelity. Initially, the field focused on the subset of transcription factors that are selectively retained in, and hence bookmark, chromatin in mitosis. However, recent studies show that many transcription factors can be retained in mitotic chromatin and that, surprisingly, such retention can be due to nonspecific chromatin binding. Here, we review the latest studies focusing on low-level transcription via promoters, rather than enhancers, as contributing to mitotic memory, as well as new insights into chromosome structure dynamics, histone modifications, cell cycle signaling, and nuclear envelope proteins that together ensure the fidelity of gene expression through a round of mitosis.
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Affiliation(s)
- Kenji Ito
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA;
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34
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Luzete-Monteiro E, Zaret KS. Structures and consequences of pioneer factor binding to nucleosomes. Curr Opin Struct Biol 2022; 75:102425. [PMID: 35863165 PMCID: PMC9976633 DOI: 10.1016/j.sbi.2022.102425] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/10/2022] [Accepted: 06/16/2022] [Indexed: 11/15/2022]
Abstract
Pioneer transcription factors are able to bind a partially exposed motif on the surface of a nucleosome, enabling the proteins to target sites in silent regions of chromatin that have been compacted by linker histone. The targeting of nucleosomal DNA by pioneer factors has been observed in vitro and in vivo, where binding can promote local nucleosome exposure that allows other transcription factors, nucleosome remodelers, and histone modifiers to engage the chromatin and elicit gene activation or further repression. Pioneer factors thereby establish new gene expression programs during cell fate changes that occur during embryonic development, regeneration, and cancer. Here, we review recent biophysical studies that reveal the structural features and strategies used by pioneer factors to accomplish nucleosome binding and the consequential changes to nucleosomes that can lead to DNA accessibility.
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Affiliation(s)
- Edgar Luzete-Monteiro
- Institute for Regenerative Medicine, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, 9-131 SCTR, 3400 Civic Center Blvd., Philadelphia, PA 19104-5157, USA.,Department of Biology, School of Arts and Sciences, University of Pennsylvania, 433 S University Ave, Philadelphia, PA 19104-4544
| | - Kenneth S. Zaret
- Institute for Regenerative Medicine, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, 9-131 SCTR, 3400 Civic Center Blvd., Philadelphia, PA 19104-5157, USA
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35
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Kinetic principles underlying pioneer function of GAGA transcription factor in live cells. Nat Struct Mol Biol 2022; 29:665-676. [PMID: 35835866 PMCID: PMC10177624 DOI: 10.1038/s41594-022-00800-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 05/27/2022] [Indexed: 11/09/2022]
Abstract
How pioneer factors interface with chromatin to promote accessibility for transcription control is poorly understood in vivo. Here, we directly visualize chromatin association by the prototypical GAGA pioneer factor (GAF) in live Drosophila hemocytes. Single-particle tracking reveals that most GAF is chromatin bound, with a stable-binding fraction showing nucleosome-like confinement residing on chromatin for more than 2 min, far longer than the dynamic range of most transcription factors. These kinetic properties require the full complement of GAF's DNA-binding, multimerization and intrinsically disordered domains, and are autonomous from recruited chromatin remodelers NURF and PBAP, whose activities primarily benefit GAF's neighbors such as Heat Shock Factor. Evaluation of GAF kinetics together with its endogenous abundance indicates that, despite on-off dynamics, GAF constitutively and fully occupies major chromatin targets, thereby providing a temporal mechanism that sustains open chromatin for transcriptional responses to homeostatic, environmental and developmental signals.
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36
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Iida S, Shinkai S, Itoh Y, Tamura S, Kanemaki MT, Onami S, Maeshima K. Single-nucleosome imaging reveals steady-state motion of interphase chromatin in living human cells. SCIENCE ADVANCES 2022; 8:eabn5626. [PMID: 35658044 PMCID: PMC9166292 DOI: 10.1126/sciadv.abn5626] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Dynamic chromatin behavior plays a critical role in various genome functions. However, it remains unclear how chromatin behavior changes during interphase, where the nucleus enlarges and genomic DNA doubles. While the previously reported chromatin movements varied during interphase when measured using a minute or longer time scale, we unveil that local chromatin motion captured by single-nucleosome imaging/tracking on a second time scale remained steady throughout G1, S, and G2 phases in live human cells. This motion mode appeared to change beyond this time scale. A defined genomic region also behaved similarly. Combined with Brownian dynamics modeling, our results suggest that this steady-state chromatin motion was mainly driven by thermal fluctuations. Steady-state motion temporarily increased following a DNA damage response. Our findings support the viscoelastic properties of chromatin. We propose that the observed steady-state chromatin motion allows cells to conduct housekeeping functions, such as transcription and DNA replication, under similar environments during interphase.
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Affiliation(s)
- Shiori Iida
- Genome Dynamics Laboratory, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Mishima, Japan
- Department of Genetics, School of Life Science, SOKENDAI, Mishima, Japan
| | - Soya Shinkai
- Laboratory for Developmental Dynamics, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Yuji Itoh
- Genome Dynamics Laboratory, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Mishima, Japan
| | - Sachiko Tamura
- Genome Dynamics Laboratory, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Mishima, Japan
| | - Masato T. Kanemaki
- Department of Genetics, School of Life Science, SOKENDAI, Mishima, Japan
- Molecular Cell Engineering Laboratory, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Mishima, Japan
| | - Shuichi Onami
- Laboratory for Developmental Dynamics, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Research Organization of Information and Systems (ROIS), Mishima, Japan
- Department of Genetics, School of Life Science, SOKENDAI, Mishima, Japan
- Corresponding author.
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37
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Ide S, Tamura S, Maeshima K. Chromatin behavior in living cells: Lessons from single‐nucleosome imaging and tracking. Bioessays 2022; 44:e2200043. [DOI: 10.1002/bies.202200043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/24/2022] [Accepted: 04/26/2022] [Indexed: 11/05/2022]
Affiliation(s)
- Satoru Ide
- Genome Dynamics Laboratory National Institute of Genetics, ROIS Mishima Shizuoka Japan
- Department of Genetics School of Life Science SOKENDAI Mishima Shizuoka Japan
| | - Sachiko Tamura
- Genome Dynamics Laboratory National Institute of Genetics, ROIS Mishima Shizuoka Japan
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory National Institute of Genetics, ROIS Mishima Shizuoka Japan
- Department of Genetics School of Life Science SOKENDAI Mishima Shizuoka Japan
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38
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Interplay between regulatory elements and chromatin topology in cellular lineage determination. Trends Genet 2022; 38:1048-1061. [DOI: 10.1016/j.tig.2022.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/02/2022] [Accepted: 05/12/2022] [Indexed: 11/16/2022]
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39
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Mehra D, Adhikari S, Banerjee C, Puchner EM. Characterizing locus specific chromatin structure and dynamics with correlative conventional and super-resolution imaging in living cells. Nucleic Acids Res 2022; 50:e78. [PMID: 35524554 PMCID: PMC9303368 DOI: 10.1093/nar/gkac314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/08/2022] [Accepted: 05/02/2022] [Indexed: 11/23/2022] Open
Abstract
The dynamic rearrangement of chromatin is critical for gene regulation, but mapping both the spatial organization of chromatin and its dynamics remains a challenge. Many structural conformations are too small to be resolved via conventional fluorescence microscopy and the long acquisition time of super-resolution photoactivated localization microscopy (PALM) precludes the structural characterization of chromatin below the optical diffraction limit in living cells due to chromatin motion. Here we develop a correlative conventional fluorescence and PALM imaging approach to quantitatively map time-averaged chromatin structure and dynamics below the optical diffraction limit in living cells. By assigning localizations to a locus as it moves, we reliably discriminate between bound and unbound dCas9 molecules, whose mobilities overlap. Our approach accounts for changes in DNA mobility and relates local chromatin motion to larger scale domain movement. In our experimental system, we show that compacted telomeres move faster and have a higher density of bound dCas9 molecules, but the relative motion of those molecules is more restricted than in less compacted telomeres. Correlative conventional and PALM imaging therefore improves the ability to analyze the mobility and time-averaged nanoscopic structural features of locus specific chromatin with single molecule sensitivity and yields unprecedented insights across length and time scales.
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Affiliation(s)
- Dushyant Mehra
- School of Physics and Astronomy, University of Minnesota, Minneapolis MN, USA.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester MN, USA
| | - Santosh Adhikari
- School of Physics and Astronomy, University of Minnesota, Minneapolis MN, USA
| | - Chiranjib Banerjee
- School of Physics and Astronomy, University of Minnesota, Minneapolis MN, USA
| | - Elias M Puchner
- School of Physics and Astronomy, University of Minnesota, Minneapolis MN, USA
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40
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Chang L, Li M, Shao S, Li C, Ai S, Xue B, Hou Y, Zhang Y, Li R, Fan X, He A, Li C, Sun Y. Nuclear peripheral chromatin-lamin B1 interaction is required for global integrity of chromatin architecture and dynamics in human cells. Protein Cell 2022; 13:258-280. [PMID: 33155082 PMCID: PMC8934373 DOI: 10.1007/s13238-020-00794-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/07/2020] [Indexed: 12/14/2022] Open
Abstract
The eukaryotic genome is folded into higher-order conformation accompanied with constrained dynamics for coordinated genome functions. However, the molecular machinery underlying these hierarchically organized three-dimensional (3D) chromatin architecture and dynamics remains poorly understood. Here by combining imaging and sequencing, we studied the role of lamin B1 in chromatin architecture and dynamics. We found that lamin B1 depletion leads to detachment of lamina-associated domains (LADs) from the nuclear periphery accompanied with global chromatin redistribution and decompaction. Consequently, the inter-chromosomal as well as inter-compartment interactions are increased, but the structure of topologically associating domains (TADs) is not affected. Using live-cell genomic loci tracking, we further proved that depletion of lamin B1 leads to increased chromatin dynamics, owing to chromatin decompaction and redistribution toward nucleoplasm. Taken together, our data suggest that lamin B1 and chromatin interactions at the nuclear periphery promote LAD maintenance, chromatin compaction, genomic compartmentalization into chromosome territories and A/B compartments and confine chromatin dynamics, supporting their crucial roles in chromatin higher-order structure and chromatin dynamics.
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Affiliation(s)
- Lei Chang
- State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871 China
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, 510530 China
| | - Mengfan Li
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871 China
- Center for Bioinformatics, School of Life Sciences, Peking University, Beijing, 100871 China
| | - Shipeng Shao
- State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871 China
| | - Chen Li
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, 100871 China
| | - Shanshan Ai
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, 100871 China
| | - Boxin Xue
- State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871 China
| | - Yingping Hou
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871 China
- Center for Bioinformatics, School of Life Sciences, Peking University, Beijing, 100871 China
| | - Yiwen Zhang
- State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871 China
| | - Ruifeng Li
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871 China
- Center for Bioinformatics, School of Life Sciences, Peking University, Beijing, 100871 China
| | - Xiaoying Fan
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, 510530 China
| | - Aibin He
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871 China
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, 100871 China
| | - Cheng Li
- Center for Bioinformatics, School of Life Sciences, Peking University, Beijing, 100871 China
- Center for Statistical Science, Peking University, Beijing, 100871 China
| | - Yujie Sun
- State Key Laboratory of Membrane Biology, School of Life Sciences, and Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871 China
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41
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Lakadamyali M. Single nucleosome tracking to study chromatin plasticity. Curr Opin Cell Biol 2022; 74:23-28. [PMID: 35033775 PMCID: PMC9064914 DOI: 10.1016/j.ceb.2021.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 12/09/2021] [Accepted: 12/13/2021] [Indexed: 02/03/2023]
Abstract
The dynamic spatial organization of chromatin within the nucleus is emerging as a key regulator of gene activity and cell phenotype. This review will focus on single molecule tracking as an enabling tool to study chromatin dynamics at the level of individual nucleosomes.
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Affiliation(s)
- Melike Lakadamyali
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA,Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA,Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA,Correspondence should be sent to M.L.:
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42
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Zhang M, Seitz C, Chang G, Iqbal F, Lin H, Liu J. A guide for single-particle chromatin tracking in live cell nuclei. Cell Biol Int 2022; 46:683-700. [PMID: 35032142 PMCID: PMC9035067 DOI: 10.1002/cbin.11762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 12/29/2021] [Accepted: 01/08/2022] [Indexed: 11/09/2022]
Abstract
The emergence of labeling strategies and live cell imaging methods enables the imaging of chromatin in living cells at single digit nanometer resolution as well as milliseconds temporal resolution. These technical breakthroughs revolutionize our understanding of chromatin structure, dynamics and functions. Single molecule tracking algorithms are usually preferred to quantify the movement of these intranucleus elements to interpret the spatiotemporal evolution of the chromatin. In this review, we will first summarize the fluorescent labeling strategy of chromatin in live cells which will be followed by a sys-tematic comparison of live cell imaging instrumentation. With the proper microscope, we will discuss the image analysis pipelines to extract the biophysical properties of the chromatin. Finally, we expect to give practical suggestions to broad biologists on how to select methods and link to the model properly according to different investigation pur-poses. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Mengdi Zhang
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Clayton Seitz
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Garrick Chang
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Fadil Iqbal
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Hua Lin
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | - Jing Liu
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA.,Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indianapolis, IN, USA.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA
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43
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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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44
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Carnesecchi J, Boumpas P, van Nierop Y Sanchez P, Domsch K, Pinto HD, Borges Pinto P, Lohmann I. The Hox transcription factor Ultrabithorax binds RNA and regulates co-transcriptional splicing through an interplay with RNA polymerase II. Nucleic Acids Res 2021; 50:763-783. [PMID: 34931250 PMCID: PMC8789087 DOI: 10.1093/nar/gkab1250] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 12/01/2021] [Accepted: 12/07/2021] [Indexed: 11/13/2022] Open
Abstract
Transcription factors (TFs) play a pivotal role in cell fate decision by coordinating gene expression programs. Although most TFs act at the DNA layer, few TFs bind RNA and modulate splicing. Yet, the mechanistic cues underlying TFs activity in splicing remain elusive. Focusing on the Drosophila Hox TF Ultrabithorax (Ubx), our work shed light on a novel layer of Ubx function at the RNA level. Transcriptome and genome-wide binding profiles in embryonic mesoderm and Drosophila cells indicate that Ubx regulates mRNA expression and splicing to promote distinct outcomes in defined cellular contexts. Our results demonstrate a new RNA-binding ability of Ubx. We find that the N51 amino acid of the DNA-binding Homeodomain is non-essential for RNA interaction in vitro, but is required for RNA interaction in vivo and Ubx splicing activity. Moreover, mutation of the N51 amino acid weakens the interaction between Ubx and active RNA Polymerase II (Pol II). Our results reveal that Ubx regulates elongation-coupled splicing, which could be coordinated by a dynamic interplay with active Pol II on chromatin. Overall, our work uncovered a novel role of the Hox TFs at the mRNA regulatory layer. This could be an essential function for other classes of TFs to control cell diversity.
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Affiliation(s)
- Julie Carnesecchi
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany.,Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Panagiotis Boumpas
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany
| | - Patrick van Nierop Y Sanchez
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany
| | - Katrin Domsch
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany.,Friedrich-Alexander-University Erlangen-Nürnberg, Department Biology, Division of Developmental Biology, Erlangen, Germany
| | - Hugo Daniel Pinto
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Pedro Borges Pinto
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany.,Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Ingrid Lohmann
- Heidelberg University, Centre for Organismal Studies (COS) Heidelberg, Department of Developmental Biology, Heidelberg, Germany
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45
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Direct neuronal reprogramming: Fast forward from new concepts toward therapeutic approaches. Neuron 2021; 110:366-393. [PMID: 34921778 DOI: 10.1016/j.neuron.2021.11.023] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/25/2021] [Accepted: 11/19/2021] [Indexed: 12/21/2022]
Abstract
Differentiated cells have long been considered fixed in their identity. However, about 20 years ago, the first direct conversion of glial cells into neurons in vitro opened the field of "direct neuronal reprogramming." Since then, neuronal reprogramming has achieved the generation of fully functional, mature neurons with remarkable efficiency, even in diseased brain environments. Beyond their clinical implications, these discoveries provided basic insights into crucial mechanisms underlying conversion of specific cell types into neurons and maintenance of neuronal identity. Here we discuss such principles, including the importance of the starter cell for shaping the outcome of neuronal reprogramming. We further highlight technical concerns for in vivo reprogramming and propose a code of conduct to avoid artifacts and pitfalls. We end by pointing out next challenges for development of less invasive cell replacement therapies for humans.
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46
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Wang Z, Deng W. Dynamic transcription regulation at the single-molecule level. Dev Biol 2021; 482:67-81. [PMID: 34896367 DOI: 10.1016/j.ydbio.2021.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 11/14/2021] [Accepted: 11/15/2021] [Indexed: 02/07/2023]
Abstract
Cell fate changes during development, differentiation, and reprogramming are largely controlled at the transcription level. The DNA-binding transcription factors (TFs) often act in a combinatorial fashion to alter chromatin states and drive cell type-specific gene expression. Recent advances in fluorescent microscopy technologies have enabled direct visualization of biomolecules involved in the process of transcription and its regulatory events at the single-molecule level in living cells. Remarkably, imaging and tracking individual TF molecules at high temporal and spatial resolution revealed that they are highly dynamic in searching and binding cognate targets, rather than static and binding constantly. In combination with investigation using techniques from biochemistry, structure biology, genetics, and genomics, a more well-rounded view of transcription regulation is emerging. In this review, we briefly cover the technical aspects of live-cell single-molecule imaging and focus on the biological relevance and interpretation of the single-molecule dynamic features of transcription regulatory events observed in the native chromatin environment of living eukaryotic cells. We also discuss how these dynamic features might shed light on mechanistic understanding of transcription regulation.
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Affiliation(s)
- Zuhui Wang
- Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Wulan Deng
- Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China; Beijing Advanced Innovation Center for Genomics (ICG), Peking University, Beijing, 100871, China; Peking-Tsinghua Center for Life Sciences (CLS), Peking University, Beijing, 100871, China; School of Life Sciences, Peking University, Beijing, 100871, China.
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47
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Abstract
To predict transcription, one needs a mechanistic understanding of how the numerous required transcription factors (TFs) explore the nuclear space to find their target genes, assemble, cooperate, and compete with one another. Advances in fluorescence microscopy have made it possible to visualize real-time TF dynamics in living cells, leading to two intriguing observations: first, most TFs contact chromatin only transiently; and second, TFs can assemble into clusters through their intrinsically disordered regions. These findings suggest that highly dynamic events and spatially structured nuclear microenvironments might play key roles in transcription regulation that are not yet fully understood. The emerging model is that while some promoters directly convert TF-binding events into on/off cycles of transcription, many others apply complex regulatory layers that ultimately lead to diverse phenotypic outputs. Cracking this kinetic code is an ongoing and challenging task that is made possible by combining innovative imaging approaches with biophysical models.
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Affiliation(s)
- Feiyue Lu
- Institute for Systems Genetics and Cell Biology Department, NYU School of Medicine, New York, New York 10016, USA
| | - Timothée Lionnet
- Institute for Systems Genetics and Cell Biology Department, NYU School of Medicine, New York, New York 10016, USA
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48
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Hansen JC, Maeshima K, Hendzel MJ. The solid and liquid states of chromatin. Epigenetics Chromatin 2021; 14:50. [PMID: 34717733 PMCID: PMC8557566 DOI: 10.1186/s13072-021-00424-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/22/2021] [Indexed: 12/14/2022] Open
Abstract
The review begins with a concise description of the principles of phase separation. This is followed by a comprehensive section on phase separation of chromatin, in which we recount the 60 years history of chromatin aggregation studies, discuss the evidence that chromatin aggregation intrinsically is a physiologically relevant liquid-solid phase separation (LSPS) process driven by chromatin self-interaction, and highlight the recent findings that under specific solution conditions chromatin can undergo liquid-liquid phase separation (LLPS) rather than LSPS. In the next section of the review, we discuss how certain chromatin-associated proteins undergo LLPS in vitro and in vivo. Some chromatin-binding proteins undergo LLPS in purified form in near-physiological ionic strength buffers while others will do so only in the presence of DNA, nucleosomes, or chromatin. The final section of the review evaluates the solid and liquid states of chromatin in the nucleus. While chromatin behaves as an immobile solid on the mesoscale, nucleosomes are mobile on the nanoscale. We discuss how this dual nature of chromatin, which fits well the concept of viscoelasticity, contributes to genome structure, emphasizing the dominant role of chromatin self-interaction.
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Affiliation(s)
- Jeffrey C Hansen
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, and Department of Genetics, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka, 411-8540, Japan.
| | - Michael J Hendzel
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
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49
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Boka AP, Mukherjee A, Mir M. Single-molecule tracking technologies for quantifying the dynamics of gene regulation in cells, tissue and embryos. Development 2021; 148:272071. [PMID: 34490887 DOI: 10.1242/dev.199744] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
For decades, we have relied on population and time-averaged snapshots of dynamic molecular scale events to understand how genes are regulated during development and beyond. The advent of techniques to observe single-molecule kinetics in increasingly endogenous contexts, progressing from in vitro studies to living embryos, has revealed how much we have missed. Here, we provide an accessible overview of the rapidly expanding family of technologies for single-molecule tracking (SMT), with the goal of enabling the reader to critically analyse single-molecule studies, as well as to inspire the application of SMT to their own work. We start by overviewing the basics of and motivation for SMT experiments, and the trade-offs involved when optimizing parameters. We then cover key technologies, including fluorescent labelling, excitation and detection optics, localization and tracking algorithms, and data analysis. Finally, we provide a summary of selected recent applications of SMT to study the dynamics of gene regulation.
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Affiliation(s)
- Alan P Boka
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Apratim Mukherjee
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Mustafa Mir
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.,Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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50
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Nguyen VQ, Ranjan A, Liu S, Tang X, Ling YH, Wisniewski J, Mizuguchi G, Li KY, Jou V, Zheng Q, Lavis LD, Lionnet T, Wu C. Spatiotemporal coordination of transcription preinitiation complex assembly in live cells. Mol Cell 2021; 81:3560-3575.e6. [PMID: 34375585 PMCID: PMC8420877 DOI: 10.1016/j.molcel.2021.07.022] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 05/18/2021] [Accepted: 07/16/2021] [Indexed: 12/17/2022]
Abstract
Transcription initiation by RNA polymerase II (RNA Pol II) requires preinitiation complex (PIC) assembly at gene promoters. In the dynamic nucleus, where thousands of promoters are broadly distributed in chromatin, it is unclear how multiple individual components converge on any target to establish the PIC. Here we use live-cell, single-molecule tracking in S. cerevisiae to visualize constrained exploration of the nucleoplasm by PIC components and Mediator's key role in guiding this process. On chromatin, TFIID/TATA-binding protein (TBP), Mediator, and RNA Pol II instruct assembly of a short-lived PIC, which occurs infrequently but efficiently within a few seconds on average. Moreover, PIC exclusion by nucleosome encroachment underscores regulated promoter accessibility by chromatin remodeling. Thus, coordinated nuclear exploration and recruitment to accessible targets underlies dynamic PIC establishment in yeast. Our study provides a global spatiotemporal model for transcription initiation in live cells.
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Affiliation(s)
- Vu Q Nguyen
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Anand Ranjan
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sheng Liu
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Xiaona Tang
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Yick Hin Ling
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Jan Wisniewski
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA; Experimental Immunology Branch, National Cancer Institute, Bethesda, MD 20892, USA
| | - Gaku Mizuguchi
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Kai Yu Li
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Vivian Jou
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Qinsi Zheng
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Luke D Lavis
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Timothée Lionnet
- Institute of Systems Genetics, Langone Medical Center, New York University, New York, NY 10016, USA
| | - Carl Wu
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Molecular Biology and Genetics, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA.
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