1
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Whitney PH, Lionnet T. The method in the madness: Transcriptional control from stochastic action at the single-molecule scale. Curr Opin Struct Biol 2024; 87:102873. [PMID: 38954990 DOI: 10.1016/j.sbi.2024.102873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 05/07/2024] [Accepted: 06/05/2024] [Indexed: 07/04/2024]
Abstract
Cell states result from the ordered activation of gene expression by transcription factors. Transcription factors face opposing design constraints: they need to be dynamic to trigger rapid cell state transitions, but also stable enough to maintain terminal cell identities indefinitely. Recent progress in live-cell single-molecule microscopy has helped define the biophysical principles underlying this paradox. Beyond transcription factor activity, single-molecule experiments have revealed that at nearly every level of transcription regulation, control emerges from multiple short-lived stochastic interactions, rather than deterministic, stable interactions typical of other biochemical pathways. This architecture generates consistent outcomes that can be rapidly choreographed. Here, we highlight recent results that demonstrate how order in transcription regulation emerges from the apparent molecular-scale chaos and discuss remaining conceptual challenges.
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Affiliation(s)
- Peter H Whitney
- Institute for Systems Genetics, New York University School of Medicine, New York, NY 10016, USA; Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | - Timothée Lionnet
- Institute for Systems Genetics, New York University School of Medicine, New York, NY 10016, USA; Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA; Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY 11201, USA.
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2
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Yang JH, Hansen AS. Enhancer selectivity in space and time: from enhancer-promoter interactions to promoter activation. Nat Rev Mol Cell Biol 2024; 25:574-591. [PMID: 38413840 DOI: 10.1038/s41580-024-00710-6] [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] [Accepted: 01/30/2024] [Indexed: 02/29/2024]
Abstract
The primary regulators of metazoan gene expression are enhancers, originally functionally defined as DNA sequences that can activate transcription at promoters in an orientation-independent and distance-independent manner. Despite being crucial for gene regulation in animals, what mechanisms underlie enhancer selectivity for promoters, and more fundamentally, how enhancers interact with promoters and activate transcription, remain poorly understood. In this Review, we first discuss current models of enhancer-promoter interactions in space and time and how enhancers affect transcription activation. Next, we discuss different mechanisms that mediate enhancer selectivity, including repression, biochemical compatibility and regulation of 3D genome structure. Through 3D polymer simulations, we illustrate how the ability of 3D genome folding mechanisms to mediate enhancer selectivity strongly varies for different enhancer-promoter interaction mechanisms. Finally, we discuss how recent technical advances may provide new insights into mechanisms of enhancer-promoter interactions and how technical biases in methods such as Hi-C and Micro-C and imaging techniques may affect their interpretation.
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Affiliation(s)
- Jin H Yang
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, Cambridge, MA, USA
| | - Anders S Hansen
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Koch Institute for Integrative Cancer Research, Cambridge, MA, USA.
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3
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Pabba MK, Meyer J, Celikay K, Schermelleh L, Rohr K, Cardoso MC. DNA choreography: correlating mobility and organization of DNA across different resolutions from loops to chromosomes. Histochem Cell Biol 2024; 162:109-131. [PMID: 38758428 PMCID: PMC11227476 DOI: 10.1007/s00418-024-02285-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: 03/27/2024] [Indexed: 05/18/2024]
Abstract
The dynamics of DNA in the cell nucleus plays a role in cellular processes and fates but the interplay of DNA mobility with the hierarchical levels of DNA organization is still underexplored. Here, we made use of DNA replication to directly label genomic DNA in an unbiased genome-wide manner. This was followed by live-cell time-lapse microscopy of the labeled DNA combining imaging at different resolutions levels simultaneously and allowing one to trace DNA motion across organization levels within the same cells. Quantification of the labeled DNA segments at different microscopic resolution levels revealed sizes comparable to the ones reported for DNA loops using 3D super-resolution microscopy, topologically associated domains (TAD) using 3D widefield microscopy, and also entire chromosomes. By employing advanced chromatin tracking and image registration, we discovered that DNA exhibited higher mobility at the individual loop level compared to the TAD level and even less at the chromosome level. Additionally, our findings indicate that chromatin movement, regardless of the resolution, slowed down during the S phase of the cell cycle compared to the G1/G2 phases. Furthermore, we found that a fraction of DNA loops and TADs exhibited directed movement with the majority depicting constrained movement. Our data also indicated spatial mobility differences with DNA loops and TADs at the nuclear periphery and the nuclear interior exhibiting lower velocity and radius of gyration than the intermediate locations. On the basis of these insights, we propose that there is a link between DNA mobility and its organizational structure including spatial distribution, which impacts cellular processes.
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Affiliation(s)
- Maruthi K Pabba
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Janis Meyer
- Biomedical Computer Vision Group, BioQuant, IPMB, Heidelberg University, Heidelberg, Germany
| | - Kerem Celikay
- Biomedical Computer Vision Group, BioQuant, IPMB, Heidelberg University, Heidelberg, Germany
| | | | - Karl Rohr
- Biomedical Computer Vision Group, BioQuant, IPMB, Heidelberg University, Heidelberg, Germany.
| | - M Cristina Cardoso
- Department of Biology, Technical University of Darmstadt, Darmstadt, Germany.
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4
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Moindrot B, Imaizumi Y, Feil R. Differential 3D genome architecture and imprinted gene expression: cause or consequence? Biochem Soc Trans 2024; 52:973-986. [PMID: 38775198 DOI: 10.1042/bst20230143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 06/27/2024]
Abstract
Imprinted genes provide an attractive paradigm to unravel links between transcription and genome architecture. The parental allele-specific expression of these essential genes - which are clustered in chromosomal domains - is mediated by parental methylation imprints at key regulatory DNA sequences. Recent chromatin conformation capture (3C)-based studies show differential organization of topologically associating domains between the parental chromosomes at imprinted domains, in embryonic stem and differentiated cells. At several imprinted domains, differentially methylated regions show allelic binding of the insulator protein CTCF, and linked focal retention of cohesin, at the non-methylated allele only. This generates differential patterns of chromatin looping between the parental chromosomes, already in the early embryo, and thereby facilitates the allelic gene expression. Recent research evokes also the opposite scenario, in which allelic transcription contributes to the differential genome organization, similarly as reported for imprinted X chromosome inactivation. This may occur through epigenetic effects on CTCF binding, through structural effects of RNA Polymerase II, or through imprinted long non-coding RNAs that have chromatin repressive functions. The emerging picture is that epigenetically-controlled differential genome architecture precedes and facilitates imprinted gene expression during development, and that at some domains, conversely, the mono-allelic gene expression also influences genome architecture.
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Affiliation(s)
- Benoit Moindrot
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Yui Imaizumi
- Institute of Molecular Genetics of Montpellier (IGMM), University of Montpellier, CNRS, Montpellier, France
| | - Robert Feil
- Institute of Molecular Genetics of Montpellier (IGMM), University of Montpellier, CNRS, Montpellier, France
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5
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Salari H, Fourel G, Jost D. Transcription regulates the spatio-temporal dynamics of genes through micro-compartmentalization. Nat Commun 2024; 15:5393. [PMID: 38918438 PMCID: PMC11199603 DOI: 10.1038/s41467-024-49727-7] [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: 07/24/2023] [Accepted: 06/17/2024] [Indexed: 06/27/2024] Open
Abstract
Although our understanding of the involvement of heterochromatin architectural factors in shaping nuclear organization is improving, there is still ongoing debate regarding the role of active genes in this process. In this study, we utilize publicly-available Micro-C data from mouse embryonic stem cells to investigate the relationship between gene transcription and 3D gene folding. Our analysis uncovers a nonmonotonic - globally positive - correlation between intragenic contact density and Pol II occupancy, independent of cohesin-based loop extrusion. Through the development of a biophysical model integrating the role of transcription dynamics within a polymer model of chromosome organization, we demonstrate that Pol II-mediated attractive interactions with limited valency between transcribed regions yield quantitative predictions consistent with chromosome-conformation-capture and live-imaging experiments. Our work provides compelling evidence that transcriptional activity shapes the 4D genome through Pol II-mediated micro-compartmentalization.
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Affiliation(s)
- Hossein Salari
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS, UMR5239, Inserm U1293, Université Claude Bernard Lyon 1, 46 Allée d'Italie, 69007, Lyon, France.
- École Normale Supérieure de Lyon, CNRS, Laboratoire de Physique, 46 Allée d'Italie, 69007, Lyon, France.
| | - Geneviève Fourel
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS, UMR5239, Inserm U1293, Université Claude Bernard Lyon 1, 46 Allée d'Italie, 69007, Lyon, France
| | - Daniel Jost
- Laboratoire de Biologie et Modélisation de la Cellule, École Normale Supérieure de Lyon, CNRS, UMR5239, Inserm U1293, Université Claude Bernard Lyon 1, 46 Allée d'Italie, 69007, Lyon, France.
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6
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Lu Z, Wang Y, Assumpção ALFV, Liu P, Kopp A, Saka S, Mcilwain SJ, Viny AD, Brand M, Pan X. Yin Yang 1 regulates cohesin complex protein SMC3 in mouse hematopoietic stem cells. Blood Adv 2024; 8:3076-3091. [PMID: 38531064 PMCID: PMC11222949 DOI: 10.1182/bloodadvances.2023011411] [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: 08/09/2023] [Revised: 02/16/2024] [Accepted: 02/26/2024] [Indexed: 03/28/2024] Open
Abstract
ABSTRACT Yin Yang 1 (YY1) and structural maintenance of chromosomes 3 (SMC3) are 2 critical chromatin structural factors that mediate long-distance enhancer-promoter interactions and promote developmentally regulated changes in chromatin architecture in hematopoietic stem/progenitor cells (HSPCs). Although YY1 has critical functions in promoting hematopoietic stem cell (HSC) self-renewal and maintaining HSC quiescence, SMC3 is required for proper myeloid lineage differentiation. However, many questions remain unanswered regarding how YY1 and SMC3 interact with each other and affect hematopoiesis. We found that YY1 physically interacts with SMC3 and cooccupies with SMC3 at a large cohort of promoters genome wide, and YY1 deficiency deregulates the genetic network governing cell metabolism. YY1 occupies the Smc3 promoter and represses SMC3 expression in HSPCs. Although deletion of 1 Smc3 allele partially restores HSC numbers and quiescence in YY1 knockout mice, Yy1-/-Smc3+/- HSCs fail to reconstitute blood after bone marrow transplant. YY1 regulates HSC metabolic pathways and maintains proper intracellular reactive oxygen species levels in HSCs, and this regulation is independent of the YY1-SMC3 axis. Our results establish a distinct YY1-SMC3 axis and its impact on HSC quiescence and metabolism.
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Affiliation(s)
- Zhanping Lu
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI
- Carbone Cancer Center, University of Wisconsin, Madison, WI
- Wisconsin Blood Cancer Research Institute, University of Wisconsin, Madison, WI
| | - Yinghua Wang
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI
- Carbone Cancer Center, University of Wisconsin, Madison, WI
- Wisconsin Blood Cancer Research Institute, University of Wisconsin, Madison, WI
| | - Anna L. F. V. Assumpção
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI
- Carbone Cancer Center, University of Wisconsin, Madison, WI
- Wisconsin Blood Cancer Research Institute, University of Wisconsin, Madison, WI
| | - Peng Liu
- Carbone Cancer Center, University of Wisconsin, Madison, WI
- Department of Biostatistics and Medical Informatics, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Audrey Kopp
- Wisconsin Blood Cancer Research Institute, University of Wisconsin, Madison, WI
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Sahitya Saka
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI
- Carbone Cancer Center, University of Wisconsin, Madison, WI
- Wisconsin Blood Cancer Research Institute, University of Wisconsin, Madison, WI
| | - Sean J. Mcilwain
- Carbone Cancer Center, University of Wisconsin, Madison, WI
- Department of Biostatistics and Medical Informatics, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Aaron D. Viny
- Division of Hematology & Oncology, Department of Medicine, Columbia University Irving Medical Center, New York, NY
- Columbia Stem Cell Initiative, Columbia University Irving Medical Center, New York, NY
- Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY
| | - Marjorie Brand
- Wisconsin Blood Cancer Research Institute, University of Wisconsin, Madison, WI
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Xuan Pan
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI
- Carbone Cancer Center, University of Wisconsin, Madison, WI
- Wisconsin Blood Cancer Research Institute, University of Wisconsin, Madison, WI
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7
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Huber J, Tanasie NL, Zernia S, Stigler J. Single-molecule imaging reveals a direct role of CTCF's zinc fingers in SA interaction and cluster-dependent RNA recruitment. Nucleic Acids Res 2024; 52:6490-6506. [PMID: 38742641 PMCID: PMC11194110 DOI: 10.1093/nar/gkae391] [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: 01/03/2024] [Revised: 03/21/2024] [Accepted: 05/01/2024] [Indexed: 05/16/2024] Open
Abstract
CTCF is a zinc finger protein associated with transcription regulation that also acts as a barrier factor for topologically associated domains (TADs) generated by cohesin via loop extrusion. These processes require different properties of CTCF-DNA interaction, and it is still unclear how CTCF's structural features may modulate its diverse roles. Here, we employ single-molecule imaging to study both full-length CTCF and truncation mutants. We show that CTCF enriches at CTCF binding sites (CBSs), displaying a longer lifetime than observed previously. We demonstrate that the zinc finger domains mediate CTCF clustering and that clustering enables RNA recruitment, possibly creating a scaffold for interaction with RNA-binding proteins like cohesin's subunit SA. We further reveal a direct recruitment and an increase of SA residence time by CTCF bound at CBSs, suggesting that CTCF-SA interactions are crucial for cohesin stability on chromatin at TAD borders. Furthermore, we establish a single-molecule T7 transcription assay and show that although a transcribing polymerase can remove CTCF from CBSs, transcription is impaired. Our study shows that context-dependent nucleic acid binding determines the multifaceted CTCF roles in genome organization and transcription regulation.
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Affiliation(s)
- Jonas Huber
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | | | - Sarah Zernia
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Johannes Stigler
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
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8
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Prevo B, Earnshaw WC. DNA packaging by molecular motors: from bacteriophage to human chromosomes. Nat Rev Genet 2024:10.1038/s41576-024-00740-y. [PMID: 38886215 DOI: 10.1038/s41576-024-00740-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2024] [Indexed: 06/20/2024]
Abstract
Dense packaging of genomic DNA is crucial for organismal survival, as DNA length always far exceeds the dimensions of the cells that contain it. Organisms, therefore, use sophisticated machineries to package their genomes. These systems range across kingdoms from a single ultra-powerful rotary motor that spools the DNA into a bacteriophage head, to hundreds of thousands of relatively weak molecular motors that coordinate the compaction of mitotic chromosomes in eukaryotic cells. Recent technological advances, such as DNA proximity-based sequencing approaches, polymer modelling and in vitro reconstitution of DNA loop extrusion, have shed light on the biological mechanisms driving DNA organization in different systems. Here, we discuss DNA packaging in bacteriophage, bacteria and eukaryotic cells, which, despite their extreme variation in size, structure and genomic content, all rely on the action of molecular motors to package their genomes.
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Affiliation(s)
- Bram Prevo
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK.
| | - William C Earnshaw
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK.
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9
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Carignano M, Kröger M, Almassalha LM, Agrawal V, Li WS, Pujadas-Liwag EM, Nap RJ, Backman V, Szleifer I. Local Volume Concentration, Packing Domains and Scaling Properties of Chromatin. ARXIV 2024:arXiv:2310.02257v3. [PMID: 38495560 PMCID: PMC10942481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
We propose the Self Returning Excluded Volume (SR-EV) model for the structure of chromatin based on stochastic rules and physical interactions. The SR-EV rules of return generate conformationally-defined domains observed by single cell imaging techniques. From nucleosome to chromosome scales, the model captures the overall chromatin organization as a corrugated system, with dense and dilute regions alternating in a manner that resembles the mixing of two disordered bi-continuous phases. This particular organizational topology is a consequence of the multiplicity of interactions and processes occurring in the nuclei, and mimicked by the proposed return rules. Single configuration properties and ensemble averages show a robust agreement between theoretical and experimental results including chromatin volume concentration, contact probability, packing domain identification and size characterization, and packing scaling behavior. Model and experimental results suggest that there is an inherent chromatin organization regardless of the cell character and resistant to an external forcing such as Rad21 degradation.
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Affiliation(s)
- Marcelo Carignano
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Martin Kröger
- Magnetism and Interface Physics & Computational Polymer Physics, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Luay Matthew Almassalha
- Department of Gastroenterology and Hepatology, Northwestern Memorial Hospital, Chicago IL 60611, USA
| | - Vasundhara Agrawal
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Wing Shun Li
- Applied Physics Program, Northwestern, University, Evanston, IL 60208, USA
| | | | - Rikkert J. Nap
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Igal Szleifer
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
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10
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Sahoo S, Kadam S, Padinhateeri R, Kumar PBS. Nonequilibrium switching of segmental states can influence compaction of chromatin. SOFT MATTER 2024; 20:4621-4632. [PMID: 38819321 DOI: 10.1039/d4sm00274a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
Knowledge about the dynamic nature of chromatin organization is essential to understand the regulation of processes like DNA transcription and repair. The existing models of chromatin assume that protein organization and chemical states along chromatin are static and the 3D organization is purely a result of protein-mediated intra-chromatin interactions. Here we present a new hypothesis that certain nonequilibrium processes, such as switching of chemical and physical states due to nucleosome assembly/disassembly or gene repression/activation, can also simultaneously influence chromatin configurations. To understand the implications of this inherent nonequilibrium switching, we present a block copolymer model of chromatin, with switching of its segmental states between two states, mimicking active/repressed or protein unbound/bound states. We show that competition between switching timescale Tt, polymer relaxation timescale τp, and segmental relaxation timescale τs can lead to non-trivial changes in chromatin organization, leading to changes in local compaction and contact probabilities. As a function of the switching timescale, the radius of gyration of chromatin shows a non-monotonic behavior with a prominent minimum when Tt ≈ τp and a maximum when Tt ≈ τs. We find that polymers with a small segment length exhibit a more compact structure than those with larger segment lengths. We also find that the switching can lead to higher contact probability and better mixing of far-away segments. Our study also shows that the nature of the distribution of chromatin clusters varies widely as we change the switching rate.
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Affiliation(s)
- Soudamini Sahoo
- Department of Physics, Indian Institute of Technology Palakkad, Palakkad, 678623, India
- Department of Physics and Astronomy, National Institute of Technology Rourkela, Rourkela, 769008, India
| | - Sangram Kadam
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
| | - Ranjith Padinhateeri
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
| | - P B Sunil Kumar
- Department of Physics, Indian Institute of Technology Palakkad, Palakkad, 678623, India
- Department of Physics, Indian Institute of Technology Madras, Chennai, 600036, India
- Center for Soft and Biological Matter, Indian Institute of Technology Madras, Chennai, 600036, India
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11
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Brandani GB, Gu C, Gopi S, Takada S. Multiscale Bayesian simulations reveal functional chromatin condensation of gene loci. PNAS NEXUS 2024; 3:pgae226. [PMID: 38881841 PMCID: PMC11179106 DOI: 10.1093/pnasnexus/pgae226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 05/30/2024] [Indexed: 06/18/2024]
Abstract
Chromatin, the complex assembly of DNA and associated proteins, plays a pivotal role in orchestrating various genomic functions. To aid our understanding of the principles underlying chromatin organization, we introduce Hi-C metainference, a Bayesian approach that integrates Hi-C contact frequencies into multiscale prior models of chromatin. This approach combines both bottom-up (the physics-based prior) and top-down (the data-driven posterior) strategies to characterize the 3D organization of a target genomic locus. We first demonstrate the capability of this method to accurately reconstruct the structural ensemble and the dynamics of a system from contact information. We then apply the approach to investigate the Sox2, Pou5f1, and Nanog loci of mouse embryonic stem cells using a bottom-up chromatin model at 1 kb resolution. We observe that the studied loci are conformationally heterogeneous and organized as crumpled globules, favoring contacts between distant enhancers and promoters. Using nucleosome-resolution simulations, we then reveal how the Nanog gene is functionally organized across the multiple scales of chromatin. At the local level, we identify diverse tetranucleosome folding motifs with a characteristic distribution along the genome, predominantly open at cis-regulatory elements and compact in between. At the larger scale, we find that enhancer-promoter contacts are driven by the transient condensation of chromatin into compact domains stabilized by extensive internucleosome interactions. Overall, this work highlights the condensed, but dynamic nature of chromatin in vivo, contributing to a deeper understanding of gene structure-function relationships.
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Affiliation(s)
- Giovanni B Brandani
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Chenyang Gu
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Soundhararajan Gopi
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Shoji Takada
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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12
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Martitz A, Schulz EG. Spatial orchestration of the genome: topological reorganisation during X-chromosome inactivation. Curr Opin Genet Dev 2024; 86:102198. [PMID: 38663040 DOI: 10.1016/j.gde.2024.102198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 03/21/2024] [Accepted: 04/05/2024] [Indexed: 06/11/2024]
Abstract
Genomes are organised through hierarchical structures, ranging from local kilobase-scale cis-regulatory contacts to large chromosome territories. Most notably, (sub)-compartments partition chromosomes according to transcriptional activity, while topologically associating domains (TADs) define cis-regulatory landscapes. The inactive X chromosome in mammals has provided unique insights into the regulation and function of the three-dimensional (3D) genome. Concurrent with silencing of the majority of genes and major alterations of its chromatin state, the X chromosome undergoes profound spatial rearrangements at multiple scales. These include the emergence of megadomains, alterations of the compartment structure and loss of the majority of TADs. Moreover, the Xist locus, which orchestrates X-chromosome inactivation, has provided key insights into regulation and function of regulatory domains. This review provides an overview of recent insights into the control of these structural rearrangements and contextualises them within a broader understanding of 3D genome organisation.
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Affiliation(s)
- Alexandra Martitz
- Systems Epigenetics, Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany; Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Edda G Schulz
- Systems Epigenetics, Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany.
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13
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Milne TA. Chromatin and aberrant enhancer activity in KMT2A rearranged acute lymphoblastic leukemia. Curr Opin Genet Dev 2024; 86:102191. [PMID: 38579381 DOI: 10.1016/j.gde.2024.102191] [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: 12/18/2023] [Revised: 03/11/2024] [Accepted: 03/19/2024] [Indexed: 04/07/2024]
Abstract
To make a multicellular organism, genes need to be transcribed at the right developmental stages and in the right tissues. DNA sequences termed 'enhancers' are crucial to achieve this. Despite concerted efforts, the exact mechanisms of enhancer activity remain elusive. Mixed lineage leukemia (MLL or KMT2A) rearrangements (MLLr), commonly observed in cases of acute lymphoblastic leukemia (ALL) and acute myeloid leukemia, produce novel in-frame fusion proteins. Recent work has shown that the MLL-AF4 fusion protein drives aberrant enhancer activity at key oncogenes in ALL, dependent on the continued presence of MLL-AF4 complex components. As well as providing some general insights into enhancer function, these observations may also provide an explanation for transcriptional heterogeneity observed in MLLr patients.
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Affiliation(s)
- Thomas A Milne
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DS, UK.
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14
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Zhang L, Bartosovic M. Single-cell mapping of cell-type specific chromatin architecture in the central nervous system. Curr Opin Struct Biol 2024; 86:102824. [PMID: 38723561 DOI: 10.1016/j.sbi.2024.102824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 03/22/2024] [Accepted: 04/08/2024] [Indexed: 05/19/2024]
Abstract
Determining how chromatin is structured in the nucleus is critical to studying its role in gene regulation. Recent advances in the analysis of single-cell chromatin architecture have considerably improved our understanding of cell-type-specific chromosome conformation and nuclear architecture. In this review, we discuss the methods used for analysis of 3D chromatin conformation, including sequencing-based methods, imaging-based techniques, and computational approaches. We further review the application of these methods in the study of the role of chromatin topology in neural development and disorders.
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Affiliation(s)
- Letian Zhang
- Department of Biochemistry and Biophysics, Svante Arrhenius väg 16C, 162 53, Stockholm, Sweden. https://twitter.com/LetianZHANG_
| | - Marek Bartosovic
- Department of Biochemistry and Biophysics, Svante Arrhenius väg 16C, 162 53, Stockholm, Sweden.
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15
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Hayward-Lara G, Fischer MD, Mir M. Dynamic microenvironments shape nuclear organization and gene expression. Curr Opin Genet Dev 2024; 86:102177. [PMID: 38461773 PMCID: PMC11162947 DOI: 10.1016/j.gde.2024.102177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/11/2024] [Accepted: 02/14/2024] [Indexed: 03/12/2024]
Abstract
Live imaging has revealed that the regulation of gene expression is largely driven by transient interactions. For example, many regulatory proteins bind chromatin for just seconds, and loop-like genomic contacts are rare and last only minutes. These discoveries have been difficult to reconcile with our canonical models that are predicated on stable and hierarchical interactions. Proteomic microenvironments that concentrate nuclear factors may explain how brief interactions can still mediate gene regulation by creating conditions where reactions occur more frequently. Here, we summarize new imaging technologies and recent discoveries implicating microenvironments as a potential driver of nuclear function. Finally, we propose that key properties of proteomic microenvironments, such as their size, enrichment, and lifetimes, are directly linked to regulatory function.
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Affiliation(s)
- Gabriela Hayward-Lara
- 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
| | - Matthew D. Fischer
- 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
| | - 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
- Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania. Philadelphia, PA 19104
- Howard Hughes Medical Institute, Children’s Hospital of Philadelphia. Philadelphia, PA 19104
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16
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Bhattacharya M, Lyda SF, Lei EP. Chromatin insulator mechanisms ensure accurate gene expression by controlling overall 3D genome organization. Curr Opin Genet Dev 2024; 87:102208. [PMID: 38810546 DOI: 10.1016/j.gde.2024.102208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/24/2024] [Accepted: 05/13/2024] [Indexed: 05/31/2024]
Abstract
Chromatin insulators are DNA-protein complexes that promote specificity of enhancer-promoter interactions and maintain distinct transcriptional states through control of 3D genome organization. In this review, we highlight recent work visualizing how mammalian CCCTC-binding factor acts as a boundary to dynamic DNA loop extrusion mediated by cohesin. We also discuss new studies in both mammals and Drosophila that elucidate biological redundancy of chromatin insulator function and interplay with transcription with respect to topologically associating domain formation. Finally, we present novel concepts in spatiotemporal regulation of chromatin insulator function during differentiation and development and possible consequences of disrupted insulator activity on cellular proliferation.
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Affiliation(s)
- Mallika Bhattacharya
- Nuclear Organization and Gene Expression Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Savanna F Lyda
- Nuclear Organization and Gene Expression Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA; Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, USA; Biological Sciences Graduate Program, University of Maryland, College Park, USA
| | - Elissa P Lei
- Nuclear Organization and Gene Expression Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.
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17
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He X, Tan Y, Feng Y, Sun Y, Ma H. Tracking pairwise genomic loci by the ParB-ParS and Noc-NBS systems in living cells. Nucleic Acids Res 2024; 52:4922-4934. [PMID: 38412314 PMCID: PMC11109969 DOI: 10.1093/nar/gkae134] [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: 11/15/2023] [Revised: 01/23/2024] [Accepted: 02/19/2024] [Indexed: 02/29/2024] Open
Abstract
The dynamics of genomic loci pairs and their interactions are essential for transcriptional regulation and genome organization. However, a robust method for tracking pairwise genomic loci in living cells is lacking. Here we developed a multicolor DNA labeling system, mParSpot (multicolor ParSpot), to track pairs of genomic loci and their interactions in living cells. The mParSpot system is derived from the ParB/ParS in the parABS system and Noc/NBS in its paralogous nucleoid occlusion system. The insertion of 16 base-pair palindromic ParSs or NBSs into the genomic locus allows the cognate binding protein ParB or Noc to spread kilobases of DNA around ParSs or NBSs for loci-specific visualization. We tracked two loci with a genomic distance of 53 kilobases and measured their spatial distance over time. Using the mParSpot system, we labeled the promoter and terminator of the MSI2 gene span 423 kb and measured their spatial distance. We also tracked the promoter and terminator dynamics of the MUC4 gene in living cells. In sum, the mParSpot is a robust and sensitive DNA labeling system for tracking genomic interactions in space and time under physiological or pathological contexts.
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Affiliation(s)
- Xiaohui He
- Gene Editing Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yuxi Tan
- Gene Editing Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Ying Feng
- Gene Editing Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yadong Sun
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Hanhui Ma
- Gene Editing Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
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18
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Chan B, Rubinstein M. Activity-driven chromatin organization during interphase: Compaction, segregation, and entanglement suppression. Proc Natl Acad Sci U S A 2024; 121:e2401494121. [PMID: 38753513 PMCID: PMC11127048 DOI: 10.1073/pnas.2401494121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 04/17/2024] [Indexed: 05/18/2024] Open
Abstract
In mammalian cells, the cohesin protein complex is believed to translocate along chromatin during interphase to form dynamic loops through a process called active loop extrusion. Chromosome conformation capture and imaging experiments have suggested that chromatin adopts a compact structure with limited interpenetration between chromosomes and between chromosomal sections. We developed a theory demonstrating that active loop extrusion causes the apparent fractal dimension of chromatin to cross-over between two and four at contour lengths on the order of 30 kilo-base pairs. The anomalously high fractal dimension [Formula: see text] is due to the inability of extruded loops to fully relax during active extrusion. Compaction on longer contour length scales extends within topologically associated domains (TADs), facilitating gene regulation by distal elements. Extrusion-induced compaction segregates TADs such that overlaps between TADs are reduced to less than 35% and increases the entanglement strand of chromatin by up to a factor of 50 to several Mega-base pairs. Furthermore, active loop extrusion couples cohesin motion to chromatin conformations formed by previously extruding cohesins and causes the mean square displacement of chromatin loci during lag times ([Formula: see text]) longer than tens of minutes to be proportional to [Formula: see text]. We validate our results with hybrid molecular dynamics-Monte Carlo simulations and show that our theory is consistent with experimental data. This work provides a theoretical basis for the compact organization of interphase chromatin, explaining the physical reason for TAD segregation and suppression of chromatin entanglements which contribute to efficient gene regulation.
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Affiliation(s)
- Brian Chan
- Department of Biomedical Engineering, Duke University, Durham, NC27708
| | - Michael Rubinstein
- Department of Biomedical Engineering, Duke University, Durham, NC27708
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC27708
- Department of Physics, Duke University, Durham, NC27708
- Department of Chemistry, Duke University, Durham, NC27708
- World Premier International Research Center Initiative–Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo001-0021, Japan
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19
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Kanata E, Duffié R, Schulz EG. Establishment and maintenance of random monoallelic expression. Development 2024; 151:dev201741. [PMID: 38813842 PMCID: PMC11166465 DOI: 10.1242/dev.201741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
This Review elucidates the regulatory principles of random monoallelic expression by focusing on two well-studied examples: the X-chromosome inactivation regulator Xist and the olfactory receptor gene family. Although the choice of a single X chromosome or olfactory receptor occurs in different developmental contexts, common gene regulatory principles guide monoallelic expression in both systems. In both cases, an event breaks the symmetry between genetically and epigenetically identical copies of the gene, leading to the expression of one single random allele, stabilized through negative feedback control. Although many regulatory steps that govern the establishment and maintenance of monoallelic expression have been identified, key pieces of the puzzle are still missing. We provide an overview of the current knowledge and models for the monoallelic expression of Xist and olfactory receptors. We discuss their similarities and differences, and highlight open questions and approaches that could guide the study of other monoallelically expressed genes.
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Affiliation(s)
- Eleni Kanata
- Systems Epigenetics, Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Rachel Duffié
- Department of Biochemistry and Molecular Biophysics, Mortimer B. Zuckerman Mind, Brain, and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Edda G. Schulz
- Systems Epigenetics, Otto Warburg Laboratories, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
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20
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Liu C, Nagashima H, Fernando N, Bass V, Gopalakrishnan J, Signorella S, Montgomery W, Lim AI, Harrison O, Reich L, Yao C, Sun HW, Brooks SR, Jiang K, Nagarajan V, Zhao Y, Jung S, Phillips R, Mikami Y, Lareau CA, Kanno Y, Jankovic D, Aryee MJ, Pękowska A, Belkaid Y, O'Shea J, Shih HY. A CTCF-binding site in the Mdm1-Il22-Ifng locus shapes cytokine expression profiles and plays a critical role in early Th1 cell fate specification. Immunity 2024; 57:1005-1018.e7. [PMID: 38697116 PMCID: PMC11108081 DOI: 10.1016/j.immuni.2024.04.007] [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: 10/31/2022] [Revised: 12/12/2023] [Accepted: 04/10/2024] [Indexed: 05/04/2024]
Abstract
Cytokine expression during T cell differentiation is a highly regulated process that involves long-range promoter-enhancer and CTCF-CTCF contacts at cytokine loci. Here, we investigated the impact of dynamic chromatin loop formation within the topologically associating domain (TAD) in regulating the expression of interferon gamma (IFN-γ) and interleukin-22 (IL-22); these cytokine loci are closely located in the genome and are associated with complex enhancer landscapes, which are selectively active in type 1 and type 3 lymphocytes. In situ Hi-C analyses revealed inducible TADs that insulated Ifng and Il22 enhancers during Th1 cell differentiation. Targeted deletion of a 17 bp boundary motif of these TADs imbalanced Th1- and Th17-associated immunity, both in vitro and in vivo, upon Toxoplasma gondii infection. In contrast, this boundary element was dispensable for cytokine regulation in natural killer cells. Our findings suggest that precise cytokine regulation relies on lineage- and developmental stage-specific interactions of 3D chromatin architectures and enhancer landscapes.
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Affiliation(s)
- Chunhong Liu
- Neuro-Immune Regulome Unit, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hiroyuki Nagashima
- Lymphocyte Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nilisha Fernando
- Neuro-Immune Regulome Unit, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Victor Bass
- Neuro-Immune Regulome Unit, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jaanam Gopalakrishnan
- Neuro-Immune Regulome Unit, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sadie Signorella
- Neuro-Immune Regulome Unit, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA; Lymphocyte Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Will Montgomery
- Neuro-Immune Regulome Unit, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ai Ing Lim
- Metaorganism Immunity Section, Laboratory of Host Immunity and Microbiome, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Oliver Harrison
- Metaorganism Immunity Section, Laboratory of Host Immunity and Microbiome, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lauren Reich
- Neuro-Immune Regulome Unit, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chen Yao
- Lymphocyte Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hong-Wei Sun
- Biodata Mining and Discovery Section, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Stephen R Brooks
- Biodata Mining and Discovery Section, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kan Jiang
- Biodata Mining and Discovery Section, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Vijayaraj Nagarajan
- Neuro-Immune Regulome Unit, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yongbing Zhao
- Lymphocyte Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Seolkyoung Jung
- Lymphocyte Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Rachael Phillips
- Lymphocyte Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yohei Mikami
- Lymphocyte Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Caleb A Lareau
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Yuka Kanno
- Lymphocyte Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dragana Jankovic
- Immunoparasitology Unit, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Martin J Aryee
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Aleksandra Pękowska
- Dioscuri Center of Chromatin Biology and Epigenomics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Yasmine Belkaid
- Metaorganism Immunity Section, Laboratory of Host Immunity and Microbiome, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - John O'Shea
- Lymphocyte Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Han-Yu Shih
- Neuro-Immune Regulome Unit, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA; National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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21
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Chiariello AM, Abraham A, Bianco S, Esposito A, Fontana A, Vercellone F, Conte M, Nicodemi M. Multiscale modelling of chromatin 4D organization in SARS-CoV-2 infected cells. Nat Commun 2024; 15:4014. [PMID: 38740770 PMCID: PMC11091192 DOI: 10.1038/s41467-024-48370-6] [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: 07/27/2023] [Accepted: 04/29/2024] [Indexed: 05/16/2024] Open
Abstract
SARS-CoV-2 can re-structure chromatin organization and alter the epigenomic landscape of the host genome, but the mechanisms that produce such changes remain unclear. Here, we use polymer physics to investigate how the chromatin of the host genome is re-organized upon infection with SARS-CoV-2. We show that re-structuring of A/B compartments can be explained by a re-modulation of intra-compartment homo-typic affinities, which leads to the weakening of A-A interactions and the enhancement of A-B mixing. At the TAD level, re-arrangements are physically described by a reduction in the loop extrusion activity coupled with an alteration of chromatin phase-separation properties, resulting in more intermingling between different TADs and a spread in space of the TADs themselves. In addition, the architecture of loci relevant to the antiviral interferon response, such as DDX58 or IFIT, becomes more variable within the 3D single-molecule population of the infected model, suggesting that viral infection leads to a loss of chromatin structural specificity. Analysing the time trajectories of pairwise gene-enhancer and higher-order contacts reveals that this variability derives from increased fluctuations in the chromatin dynamics of infected cells. This suggests that SARS-CoV-2 alters gene regulation by impacting the stability of the contact network in time.
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Affiliation(s)
- Andrea M Chiariello
- Dipartimento di Fisica, Università degli Studi di Napoli Federico II, and INFN Napoli, Complesso Universitario di Monte Sant'Angelo, 80126, Naples, Italy.
| | - Alex Abraham
- Dipartimento di Fisica, Università degli Studi di Napoli Federico II, and INFN Napoli, Complesso Universitario di Monte Sant'Angelo, 80126, Naples, Italy
| | - Simona Bianco
- Dipartimento di Fisica, Università degli Studi di Napoli Federico II, and INFN Napoli, Complesso Universitario di Monte Sant'Angelo, 80126, Naples, Italy
| | - Andrea Esposito
- Dipartimento di Fisica, Università degli Studi di Napoli Federico II, and INFN Napoli, Complesso Universitario di Monte Sant'Angelo, 80126, Naples, Italy
| | - Andrea Fontana
- Dipartimento di Fisica, Università degli Studi di Napoli Federico II, and INFN Napoli, Complesso Universitario di Monte Sant'Angelo, 80126, Naples, Italy
| | - Francesca Vercellone
- Dipartimento di Ingegneria Elettrica e delle Tecnologie dell'Informazione - DIETI, Università degli Studi di Napoli Federico II, and INFN Napoli, Via Claudio 21, 80125, Naples, Italy
| | - Mattia Conte
- Dipartimento di Fisica, Università degli Studi di Napoli Federico II, and INFN Napoli, Complesso Universitario di Monte Sant'Angelo, 80126, Naples, Italy
| | - Mario Nicodemi
- Dipartimento di Fisica, Università degli Studi di Napoli Federico II, and INFN Napoli, Complesso Universitario di Monte Sant'Angelo, 80126, Naples, Italy.
- Berlin Institute for Medical Systems Biology at the Max Delbruck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.
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22
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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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23
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Camerino M, Chang W, Cvekl A. Analysis of long-range chromatin contacts, compartments and looping between mouse embryonic stem cells, lens epithelium and lens fibers. Epigenetics Chromatin 2024; 17:10. [PMID: 38643244 PMCID: PMC11031936 DOI: 10.1186/s13072-024-00533-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: 11/15/2023] [Accepted: 03/08/2024] [Indexed: 04/22/2024] Open
Abstract
BACKGROUND Nuclear organization of interphase chromosomes involves individual chromosome territories, "open" and "closed" chromatin compartments, topologically associated domains (TADs) and chromatin loops. The DNA- and RNA-binding transcription factor CTCF together with the cohesin complex serve as major organizers of chromatin architecture. Cellular differentiation is driven by temporally and spatially coordinated gene expression that requires chromatin changes of individual loci of various complexities. Lens differentiation represents an advantageous system to probe transcriptional mechanisms underlying tissue-specific gene expression including high transcriptional outputs of individual crystallin genes until the mature lens fiber cells degrade their nuclei. RESULTS Chromatin organization between mouse embryonic stem (ES) cells, newborn (P0.5) lens epithelium and fiber cells were analyzed using Hi-C. Localization of CTCF in both lens chromatins was determined by ChIP-seq and compared with ES cells. Quantitative analyses show major differences between number and size of TADs and chromatin loop size between these three cell types. In depth analyses show similarities between lens samples exemplified by overlaps between compartments A and B. Lens epithelium-specific CTCF peaks are found in mostly methylated genomic regions while lens fiber-specific and shared peaks occur mostly within unmethylated DNA regions. Major differences in TADs and loops are illustrated at the ~ 500 kb Pax6 locus, encoding the critical lens regulatory transcription factor and within a larger ~ 15 Mb WAGR locus, containing Pax6 and other loci linked to human congenital diseases. Lens and ES cell Hi-C data (TADs and loops) together with ATAC-seq, CTCF, H3K27ac, H3K27me3 and ENCODE cis-regulatory sites are shown in detail for the Pax6, Sox1 and Hif1a loci, multiple crystallin genes and other important loci required for lens morphogenesis. The majority of crystallin loci are marked by unexpectedly high CTCF-binding across their transcribed regions. CONCLUSIONS Our study has generated the first data on 3-dimensional (3D) nuclear organization in lens epithelium and lens fibers and directly compared these data with ES cells. These findings generate novel insights into lens-specific transcriptional gene control, open new research avenues to study transcriptional condensates in lens fiber cells, and enable studies of non-coding genetic variants linked to cataract and other lens and ocular abnormalities.
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Affiliation(s)
- Michael Camerino
- The Departments Genetics, Albert Einstein College of Medicine, NY10461, Bronx, USA
| | - William Chang
- Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, NY10461, Bronx, USA
| | - Ales Cvekl
- The Departments Genetics, Albert Einstein College of Medicine, NY10461, Bronx, USA.
- Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, NY10461, Bronx, USA.
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24
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Lizana L, Schwartz YB. The scales, mechanisms, and dynamics of the genome architecture. SCIENCE ADVANCES 2024; 10:eadm8167. [PMID: 38598632 PMCID: PMC11006219 DOI: 10.1126/sciadv.adm8167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 03/06/2024] [Indexed: 04/12/2024]
Abstract
Even when split into several chromosomes, DNA molecules that make up our genome are too long to fit into the cell nuclei unless massively folded. Such folding must accommodate the need for timely access to selected parts of the genome by transcription factors, RNA polymerases, and DNA replication machinery. Here, we review our current understanding of the genome folding inside the interphase nuclei. We consider the resulting genome architecture at three scales with a particular focus on the intermediate (meso) scale and summarize the insights gained from recent experimental observations and diverse computational models.
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Affiliation(s)
- Ludvig Lizana
- Integrated Science Lab, Department of Physics, Umeå University, Umeå, Sweden
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25
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Brückner DB, Broedersz CP. Learning dynamical models of single and collective cell migration: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:056601. [PMID: 38518358 DOI: 10.1088/1361-6633/ad36d2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 03/22/2024] [Indexed: 03/24/2024]
Abstract
Single and collective cell migration are fundamental processes critical for physiological phenomena ranging from embryonic development and immune response to wound healing and cancer metastasis. To understand cell migration from a physical perspective, a broad variety of models for the underlying physical mechanisms that govern cell motility have been developed. A key challenge in the development of such models is how to connect them to experimental observations, which often exhibit complex stochastic behaviours. In this review, we discuss recent advances in data-driven theoretical approaches that directly connect with experimental data to infer dynamical models of stochastic cell migration. Leveraging advances in nanofabrication, image analysis, and tracking technology, experimental studies now provide unprecedented large datasets on cellular dynamics. In parallel, theoretical efforts have been directed towards integrating such datasets into physical models from the single cell to the tissue scale with the aim of conceptualising the emergent behaviour of cells. We first review how this inference problem has been addressed in both freely migrating and confined cells. Next, we discuss why these dynamics typically take the form of underdamped stochastic equations of motion, and how such equations can be inferred from data. We then review applications of data-driven inference and machine learning approaches to heterogeneity in cell behaviour, subcellular degrees of freedom, and to the collective dynamics of multicellular systems. Across these applications, we emphasise how data-driven methods can be integrated with physical active matter models of migrating cells, and help reveal how underlying molecular mechanisms control cell behaviour. Together, these data-driven approaches are a promising avenue for building physical models of cell migration directly from experimental data, and for providing conceptual links between different length-scales of description.
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Affiliation(s)
- David B Brückner
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Chase P Broedersz
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
- Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilian-University Munich, Theresienstr. 37, D-80333 Munich, Germany
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26
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Kim KL, Rahme GJ, Goel VY, El Farran CA, Hansen AS, Bernstein BE. Dissection of a CTCF topological boundary uncovers principles of enhancer-oncogene regulation. Mol Cell 2024; 84:1365-1376.e7. [PMID: 38452764 PMCID: PMC10997458 DOI: 10.1016/j.molcel.2024.02.007] [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: 10/03/2023] [Revised: 01/03/2024] [Accepted: 02/08/2024] [Indexed: 03/09/2024]
Abstract
Enhancer-gene communication is dependent on topologically associating domains (TADs) and boundaries enforced by the CCCTC-binding factor (CTCF) insulator, but the underlying structures and mechanisms remain controversial. Here, we investigate a boundary that typically insulates fibroblast growth factor (FGF) oncogenes but is disrupted by DNA hypermethylation in gastrointestinal stromal tumors (GISTs). The boundary contains an array of CTCF sites that enforce adjacent TADs, one containing FGF genes and the other containing ANO1 and its putative enhancers, which are specifically active in GIST and its likely cell of origin. We show that coordinate disruption of four CTCF motifs in the boundary fuses the adjacent TADs, allows the ANO1 enhancer to contact FGF3, and causes its robust induction. High-resolution micro-C maps reveal specific contact between transcription initiation sites in the ANO1 enhancer and FGF3 promoter that quantitatively scales with FGF3 induction such that modest changes in contact frequency result in strong changes in expression, consistent with a causal relationship.
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Affiliation(s)
- Kyung Lock Kim
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Departments of Cell Biology and Pathology, Harvard Medical School, Boston, MA 02215, USA
| | - Gilbert J Rahme
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Departments of Cell Biology and Pathology, Harvard Medical School, Boston, MA 02215, USA
| | - Viraat Y Goel
- Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA
| | - Chadi A El Farran
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Departments of Cell Biology and Pathology, Harvard Medical School, Boston, MA 02215, USA
| | - Anders S Hansen
- Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA
| | - Bradley E Bernstein
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Departments of Cell Biology and Pathology, Harvard Medical School, Boston, MA 02215, USA.
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27
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Hwang DW, Maekiniemi A, Singer RH, Sato H. Real-time single-molecule imaging of transcriptional regulatory networks in living cells. Nat Rev Genet 2024; 25:272-285. [PMID: 38195868 DOI: 10.1038/s41576-023-00684-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2023] [Indexed: 01/11/2024]
Abstract
Gene regulatory networks drive the specific transcriptional programmes responsible for the diversification of cell types during the development of multicellular organisms. Although our knowledge of the genes involved in these dynamic networks has expanded rapidly, our understanding of how transcription is spatiotemporally regulated at the molecular level over a wide range of timescales in the small volume of the nucleus remains limited. Over the past few decades, advances in the field of single-molecule fluorescence imaging have enabled real-time behaviours of individual transcriptional components to be measured in living cells and organisms. These efforts are now shedding light on the dynamic mechanisms of transcription, revealing not only the temporal rules but also the spatial coordination of underlying molecular interactions during various biological events.
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Affiliation(s)
- Dong-Woo Hwang
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Anna Maekiniemi
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Robert H Singer
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA
| | - Hanae Sato
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY, USA.
- Nano Life Science Institute (WPI-Nano LSI), Kanazawa University, Kakuma-machi, Kanazawa, Japan.
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28
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Rittenhouse NL, Dowen JM. Cohesin regulation and roles in chromosome structure and function. Curr Opin Genet Dev 2024; 85:102159. [PMID: 38382406 PMCID: PMC10947815 DOI: 10.1016/j.gde.2024.102159] [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: 09/12/2023] [Revised: 01/22/2024] [Accepted: 01/27/2024] [Indexed: 02/23/2024]
Abstract
Chromosome structure regulates DNA-templated processes such as transcription of genes. Dynamic changes to chromosome structure occur during development and in disease contexts. The cohesin complex is a molecular motor that regulates chromosome structure by generating DNA loops that bring two distal genomic sites into close spatial proximity. There are many open questions regarding the formation and dissolution of DNA loops, as well as the role(s) of DNA loops in regulating transcription of the interphase genome. This review focuses on recent discoveries that provide molecular insights into the role of cohesin and chromosome structure in gene transcription during development and disease.
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Affiliation(s)
- Natalie L Rittenhouse
- Curriculum in Genetics & Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jill M Dowen
- Department of Biophysics & Biochemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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29
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Woodworth MA, Lakadamyali M. Toward a comprehensive view of gene architecture during transcription. Curr Opin Genet Dev 2024; 85:102154. [PMID: 38309073 PMCID: PMC10989512 DOI: 10.1016/j.gde.2024.102154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/20/2023] [Accepted: 01/09/2024] [Indexed: 02/05/2024]
Abstract
The activation of genes within the nucleus of eukaryotic cells is a tightly regulated process, orchestrated by a complex interplay of various physical properties and interacting factors. Studying the multitude of components and features that collectively contribute to gene activation has proven challenging due to the complexities of simultaneously visualizing the dynamic and transiently interacting elements that coalesce within the small space occupied by each individual gene. However, various labeling and imaging advances are now starting to overcome this challenge, enabling visualization of gene activation at different lengths and timescales. In this review, we aim to highlight these microscopy-based advances and suggest how they can be combined to provide a comprehensive view of the mechanisms regulating gene activation.
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Affiliation(s)
- Marcus A Woodworth
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Melike Lakadamyali
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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30
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Yuan T, Yan H, Bailey MLP, Williams JF, Surovtsev I, King MC, Mochrie SGJ. Effect of loops on the mean-square displacement of Rouse-model chromatin. Phys Rev E 2024; 109:044502. [PMID: 38755928 DOI: 10.1103/physreve.109.044502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 02/16/2024] [Indexed: 05/18/2024]
Abstract
Chromatin polymer dynamics are commonly described using the classical Rouse model. The subsequent discovery, however, of intermediate-scale chromatin organization known as topologically associating domains (TADs) in experimental Hi-C contact maps for chromosomes across the tree of life, together with the success of loop extrusion factor (LEF) model in explaining TAD formation, motivates efforts to understand the effect of loops and loop extrusion on chromatin dynamics. This paper seeks to fulfill this need by combining LEF-model simulations with extended Rouse-model polymer simulations to investigate the dynamics of chromatin with loops and dynamic loop extrusion. We show that loops significantly suppress the averaged mean-square displacement (MSD) of a gene locus, consistent with recent experiments that track fluorescently labeled chromatin loci. We also find that loops reduce the MSD's stretching exponent from the classical Rouse-model value of 1/2 to a loop-density-dependent value in the 0.45-0.40 range. Remarkably, stretching exponent values in this range have also been observed in recent experiments [Weber et al., Phys. Rev. Lett. 104, 238102 (2010)0031-900710.1103/PhysRevLett.104.238102; Bailey et al., Mol. Biol. Cell 34, ar78 (2023)1059-152410.1091/mbc.E23-04-0119]. We also show that the dynamics of loop extrusion itself negligibly affects chromatin mobility. By studying static "rosette" loop configurations, we also demonstrate that chromatin MSDs and stretching exponents depend on the location of the locus in question relative to the position of the loops and on the local friction environment.
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Affiliation(s)
- Tianyu Yuan
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, Connecticut 06520, USA
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Hao Yan
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, Connecticut 06520, USA
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Mary Lou P Bailey
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, Connecticut 06520, USA
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Jessica F Williams
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Ivan Surovtsev
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Megan C King
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, Connecticut 06520, USA
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520, USA
- Department of Molecular, Cell and Developmental Biology, Yale University, New Haven, Connecticut 06511, USA
| | - Simon G J Mochrie
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, Connecticut 06520, USA
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
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31
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Rekaik H, Duboule D. A CTCF-dependent mechanism underlies the Hox timer: relation to a segmented body plan. Curr Opin Genet Dev 2024; 85:102160. [PMID: 38377879 DOI: 10.1016/j.gde.2024.102160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 01/27/2024] [Accepted: 01/28/2024] [Indexed: 02/22/2024]
Abstract
During gastrulation, Hox genes are activated in a time-sequence that follows the order of the genes along their clusters. This property, which is observed in all animals that develop following a progressive rostral-to-caudal morphogenesis, is associated with changes in the chromatin structure and epigenetic profiles of Hox clusters, suggesting a process at least partly based on sequential gene accessibility. Here, we discuss recent work on this issue, as well as a possible mechanism based on the surprising conservation in both the distribution and orientation of CTCF sites inside vertebrate Hox clusters.
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Affiliation(s)
- Hocine Rekaik
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland; Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France. https://twitter.com/@hocine_Rekaik
| | - Denis Duboule
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland; Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France.
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32
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Cheng G, Pratto F, Brick K, Li X, Alleva B, Huang M, Lam G, Camerini-Otero RD. High resolution maps of chromatin reorganization through mouse meiosis reveal novel features of the 3D meiotic structure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.25.586627. [PMID: 38903112 PMCID: PMC11188084 DOI: 10.1101/2024.03.25.586627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
When germ cells transition from the mitotic cycle into meiotic prophase I (MPI), chromosomes condense into an array of chromatin loops that are required to promote homolog pairing and genetic recombination. To identify the changes in chromosomal conformation, we isolated nuclei on a trajectory from spermatogonia to the end of MPI. At each stage along this trajectory, we built genomic interaction maps with the highest temporal and spatial resolution to date. The changes in chromatin folding coincided with a concurrent decline in mitotic cohesion and a rise in meiotic cohesin complexes. We found that the stereotypical large-scale A and B compartmentalization was lost during meiotic prophase I alongside the loss of topological associating domains (TADs). Still, local subcompartments were detected and maintained throughout meiosis. The enhanced Micro-C resolution revealed that, despite the loss of TADs, higher frequency contact sites between two loci were detectable during meiotic prophase I coinciding with CTCF bound sites. The pattern of interactions around these CTCF sites with their neighboring loci showed that CTCF sites were often anchoring the meiotic loops. Additionally, the localization of CTCF to the meiotic axes indicated that these anchors were at the base of loops. Strikingly, even in the face of the dramatic reconfiguration of interphase chromatin into a condensed loop-array, the interactions between regulatory elements remained well preserved. This establishes a potential mechanism for how the meiotic chromatin maintains active transcription within a highly structured genome. In summary, the high temporal and spatial resolution of these data revealed previously unappreciated aspects of mammalian meiotic chromatin organization.
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Affiliation(s)
- Gang Cheng
- Genetics and Biochemistry Branch, NIDDK, National Institutes of Health, Bethesda, MD, USA
| | - Florencia Pratto
- Genetics and Biochemistry Branch, NIDDK, National Institutes of Health, Bethesda, MD, USA
| | - Kevin Brick
- Genetics and Biochemistry Branch, NIDDK, National Institutes of Health, Bethesda, MD, USA
| | - Xin Li
- Genetics and Biochemistry Branch, NIDDK, National Institutes of Health, Bethesda, MD, USA
| | - Benjamin Alleva
- Genetics and Biochemistry Branch, NIDDK, National Institutes of Health, Bethesda, MD, USA
| | - Mini Huang
- Present address: Sun Yat-Sen University, School of Medicine, Shen Zhen, China
| | - Gabriel Lam
- Present address: RNA Regulation Section, NIA, National Institutes of Health, Baltimore, MD, USA
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33
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Belan S, Parfenyev V. Footprints of loop extrusion in statistics of intra-chromosomal distances: An analytically solvable model. J Chem Phys 2024; 160:124901. [PMID: 38516975 DOI: 10.1063/5.0199573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 03/06/2024] [Indexed: 03/23/2024] Open
Abstract
Active loop extrusion-the process of formation of dynamically growing chromatin loops due to the motor activity of DNA-binding protein complexes-is a firmly established mechanism responsible for chromatin spatial organization at different stages of a cell cycle in eukaryotes and bacteria. The theoretical insight into the effect of loop extrusion on the experimentally measured statistics of chromatin conformation can be gained with an appropriately chosen polymer model. Here, we consider the simplest analytically solvable model of an interphase chromosome, which is treated as an ideal chain with disorder of sufficiently sparse random loops whose conformations are sampled from the equilibrium ensemble. This framework allows us to arrive at the closed-form analytical expression for the mean-squared distance between pairs of genomic loci, which is valid beyond the one-loop approximation in diagrammatic representation. In addition, we analyze the loop-induced deviation of chain conformations from the Gaussian statistics by calculating kurtosis of probability density of the pairwise separation vector. The presented results suggest the possible ways of estimating the characteristics of the loop extrusion process based on the experimental data on the scale-dependent statistics of intra-chromosomal pair-wise distances.
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Affiliation(s)
- Sergey Belan
- Landau Institute for Theoretical Physics, Russian Academy of Sciences, 1-A Akademika Semenova Av., 142432 Chernogolovka, Russia
- National Research University Higher School of Economics, Faculty of Physics, Myasnitskaya 20, 101000 Moscow, Russia
| | - Vladimir Parfenyev
- Landau Institute for Theoretical Physics, Russian Academy of Sciences, 1-A Akademika Semenova Av., 142432 Chernogolovka, Russia
- National Research University Higher School of Economics, Faculty of Physics, Myasnitskaya 20, 101000 Moscow, Russia
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34
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Kim M, Wang P, Clow PA, Chien I(E, Wang X, Peng J, Chai H, Liu X, Lee B, Ngan CY, Yue F, Milenkovic O, Chuang JH, Wei CL, Casellas R, Cheng AW, Ruan Y. Multifaceted roles of cohesin in regulating transcriptional loops. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.25.586715. [PMID: 38585764 PMCID: PMC10996690 DOI: 10.1101/2024.03.25.586715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Cohesin is required for chromatin loop formation. However, its precise role in regulating gene transcription remains largely unknown. We investigated the relationship between cohesin and RNA Polymerase II (RNAPII) using single-molecule mapping and live-cell imaging methods in human cells. Cohesin-mediated transcriptional loops were highly correlated with those of RNAPII and followed the direction of gene transcription. Depleting RAD21, a subunit of cohesin, resulted in the loss of long-range (>100 kb) loops between distal (super-)enhancers and promoters of cell-type-specific genes. By contrast, the short-range (<50 kb) loops were insensitive to RAD21 depletion and connected genes that are mostly housekeeping. This result explains why only a small fraction of genes are affected by the loss of long-range chromatin interactions due to cohesin depletion. Remarkably, RAD21 depletion appeared to up-regulate genes located in early initiation zones (EIZ) of DNA replication, and the EIZ signals were amplified drastically without RAD21. Our results revealed new mechanistic insights of cohesin's multifaceted roles in establishing transcriptional loops, preserving long-range chromatin interactions for cell-specific genes, and maintaining timely order of DNA replication.
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Affiliation(s)
- Minji Kim
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
- Present address: Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109, USA
- Equal contributions
| | - Ping Wang
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Evanston, IL, 60201, USA
- Equal contributions
| | - Patricia A. Clow
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
- Equal contributions
| | - I (Eli) Chien
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61820, USA
| | - Xiaotao Wang
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Reproduction and Development, Shanghai, China
| | - Jianhao Peng
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61820, USA
| | - Haoxi Chai
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Xiyuan Liu
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, P.R. China
| | - Byoungkoo Lee
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Chew Yee Ngan
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Feng Yue
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Evanston, IL, 60201, USA
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Olgica Milenkovic
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61820, USA
| | - Jeffrey H. Chuang
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, 06030, USA
| | - Chia-Lin Wei
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Rafael Casellas
- Hematopoietic Biology and Malignancy, MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Albert W. Cheng
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, 85281, USA
| | - Yijun Ruan
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang Province, 310058, P.R. China
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Shin S, Shi G, Cho HW, Thirumalai D. Transcription-induced active forces suppress chromatin motion. Proc Natl Acad Sci U S A 2024; 121:e2307309121. [PMID: 38489381 PMCID: PMC10963020 DOI: 10.1073/pnas.2307309121] [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: 05/02/2023] [Accepted: 02/06/2024] [Indexed: 03/17/2024] Open
Abstract
The organization of interphase chromosomes in a number of species is starting to emerge thanks to advances in a variety of experimental techniques. However, much less is known about the dynamics, especially in the functional states of chromatin. Some experiments have shown that the motility of individual loci in human interphase chromosome decreases during transcription and increases upon inhibiting transcription. This is a counterintuitive finding because it is thought that the active mechanical force (F) on the order of ten piconewtons, generated by RNA polymerase II (RNAPII) that is presumably transmitted to the gene-rich region of the chromatin, would render it more open, thus enhancing the mobility. We developed a minimal active copolymer model for interphase chromosomes to investigate how F affects the dynamical properties of chromatin. The movements of the loci in the gene-rich region are suppressed in an intermediate range of F and are enhanced at small F values, which has also been observed in experiments. In the intermediate F, the bond length between consecutive loci increases, becoming commensurate with the distance at the minimum of the attractive interaction between nonbonded loci. This results in a transient disorder-to-order transition, leading to a decreased mobility during transcription. Strikingly, the F-dependent change in the locus dynamics preserves the organization of the chromosome at [Formula: see text]. Transient ordering of the loci, which is not found in the polymers with random epigenetic profiles, in the gene-rich region might be a plausible mechanism for nucleating a dynamic network involving transcription factors, RNAPII, and chromatin.
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Affiliation(s)
- Sucheol Shin
- Department of Chemistry, The University of Texas at Austin, Austin, TX78712
| | - Guang Shi
- Department of Chemistry, The University of Texas at Austin, Austin, TX78712
- Department of Materials Science, University of Illinois, Urbana, IL61801
| | - Hyun Woo Cho
- Department of Fine Chemistry and Center for Functional Biomaterials, Seoul National University of Science and Technology, Seoul01811, Republic of Korea
| | - D. Thirumalai
- Department of Chemistry, The University of Texas at Austin, Austin, TX78712
- Department of Physics, The University of Texas at Austin, Austin, TX78712
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36
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Fleck K, Luria V, Garag N, Karger A, Hunter T, Marten D, Phu W, Nam KM, Sestan N, O’Donnell-Luria AH, Erceg J. Functional associations of evolutionarily recent human genes exhibit sensitivity to the 3D genome landscape and disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.17.585403. [PMID: 38559085 PMCID: PMC10980080 DOI: 10.1101/2024.03.17.585403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Genome organization is intricately tied to regulating genes and associated cell fate decisions. In this study, we examine the positioning and functional significance of human genes, grouped by their evolutionary age, within the 3D organization of the genome. We reveal that genes of different evolutionary origin have distinct positioning relationships with both domains and loop anchors, and remarkably consistent relationships with boundaries across cell types. While the functional associations of each group of genes are primarily cell type-specific, such associations of conserved genes maintain greater stability across 3D genomic features and disease than recently evolved genes. Furthermore, the expression of these genes across various tissues follows an evolutionary progression, such that RNA levels increase from young genes to ancient genes. Thus, the distinct relationships of gene evolutionary age, function, and positioning within 3D genomic features contribute to tissue-specific gene regulation in development and disease.
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Affiliation(s)
- Katherine Fleck
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Victor Luria
- Department of Neuroscience, Yale School of Medicine, New Haven, CT 06510
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, MA 02115
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115
| | - Nitanta Garag
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
| | - Amir Karger
- IT-Research Computing, Harvard Medical School, Boston, MA 02115
| | - Trevor Hunter
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
| | - Daniel Marten
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, MA 02115
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142
| | - William Phu
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, MA 02115
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142
| | - Kee-Myoung Nam
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06510
| | - Nenad Sestan
- Department of Neuroscience, Yale School of Medicine, New Haven, CT 06510
| | - Anne H. O’Donnell-Luria
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, MA 02115
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115
| | - Jelena Erceg
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
- Department of Genetics and Genome Sciences, University of Connecticut Health Center, Farmington, CT 06030
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37
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Murphy SE, Boettiger AN. Polycomb repression of Hox genes involves spatial feedback but not domain compaction or phase transition. Nat Genet 2024; 56:493-504. [PMID: 38361032 DOI: 10.1038/s41588-024-01661-6] [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: 01/06/2023] [Accepted: 01/10/2024] [Indexed: 02/17/2024]
Abstract
Polycomb group proteins have a critical role in silencing transcription during development. It is commonly proposed that Polycomb-dependent changes in genome folding, which compact chromatin, contribute directly to repression by blocking the binding of activating complexes. Recently, it has also been argued that liquid-liquid demixing of Polycomb proteins facilitates this compaction and repression by phase-separating target genes into a membraneless compartment. To test these models, we used Optical Reconstruction of Chromatin Architecture to trace the Hoxa gene cluster, a canonical Polycomb target, in thousands of single cells. Across multiple cell types, we find that Polycomb-bound chromatin frequently explores decompact states and partial mixing with neighboring chromatin, while remaining uniformly repressed, challenging the repression-by-compaction or phase-separation models. Using polymer simulations, we show that these observed flexible ensembles can be explained by 'spatial feedback'-transient contacts that contribute to the propagation of the epigenetic state (epigenetic memory), without inducing a globular organization.
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Affiliation(s)
- Sedona Eve Murphy
- Department of Genetics, Stanford University, Stanford, CA, USA
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
- Department of Cell Biology, Yale University, New Haven, CT, USA
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38
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Busby T, Misteli T. Building chromatin from the ground up. Nat Genet 2024; 56:360-361. [PMID: 38351384 DOI: 10.1038/s41588-024-01666-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2024]
Affiliation(s)
- Theodore Busby
- National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Tom Misteli
- National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
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39
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Dutta S, Ghosh A, Spakowitz AJ. Effect of local active fluctuations on structure and dynamics of flexible biopolymers. SOFT MATTER 2024; 20:1694-1701. [PMID: 38226903 DOI: 10.1039/d3sm01491f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
Active fluctuations play a significant role in the structure and dynamics of biopolymers (e.g. chromatin and cytoskeletal proteins) that are instrumental in the functioning of living cells. For a large range of experimentally accessible length and time scales, these polymers can be represented as flexible chains that are subjected to spatially and temporally varying fluctuating forces. In this work, we introduce a mathematical framework that correlates the spatial and temporal patterns of the fluctuations to different observables that describe the dynamics and conformations of the polymer. We demonstrate the power of this approach by analyzing the case of a point fluctuation on the polymer with an exponential decay of correlation in time with a finite time constant. Specifically, we identify the length and time scale over which the behavior of the polymer exhibits a significant departure from the behavior of a Rouse chain and the range of impact of the fluctuation along the chain. Furthermore, we show that the conformation of the polymer retains the memory of the active fluctuation from earlier times. Altogether, this work sets the basis for understanding and interpreting the role of spatio-temporal patterns of fluctuations in the dynamics, conformation, and functionality of biopolymers in living cells.
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Affiliation(s)
- Sayantan Dutta
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, USA
| | - Ashesh Ghosh
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, USA
| | - Andrew J Spakowitz
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, USA
- Department of Material Science and Engineering, Stanford University, Stanford, California 94305, USA
- Biophysics Program, Stanford University, Stanford, California 94305, USA.
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40
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Garimberti E, Federico C, Ragusa D, Bruno F, Saccone S, Bridger JM, Tosi S. Alterations in Genome Organization in Lymphoma Cell Nuclei due to the Presence of the t(14;18) Translocation. Int J Mol Sci 2024; 25:2377. [PMID: 38397052 PMCID: PMC10889133 DOI: 10.3390/ijms25042377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/10/2024] [Accepted: 02/15/2024] [Indexed: 02/25/2024] Open
Abstract
Chromosomal rearrangements have been shown to alter genome organization, consequently having an impact on gene expression. Studies on certain types of leukemia have shown that gene expression can be exacerbated by the altered nuclear positioning of fusion genes arising from chromosomal translocations. However, studies on lymphoma have been, so far, very limited. The scope of this study was to explore genome organization in lymphoma cells carrying the t(14;18)(q32;q21) rearrangement known to results in over-expression of the BCL2 gene. In order to achieve this aim, we used fluorescence in situ hybridization to carefully map the positioning of whole chromosome territories and individual genes involved in translocation in the lymphoma-derived cell line Pfeiffer. Our data show that, although there is no obvious alteration in the positioning of the whole chromosome territories, the translocated genes may take the nuclear positioning of either of the wild-type genes. Furthermore, the BCL2 gene was looping out in a proportion of nuclei with the t(14;18) translocation but not in control nuclei without the translocation, indicating that chromosome looping may be an essential mechanism for BCL2 expression in lymphoma cells.
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Affiliation(s)
- Elisa Garimberti
- Clinical Genomics Laboratory, Royal Marsden NHS Foundation Trust, London SW3 6JJ, UK;
| | - Concetta Federico
- Department of Biological, Geological, and Environmental Sciences, University of Catania, Via Androne 81, 95124 Catania, Italy; (C.F.); (F.B.); (S.S.)
| | - Denise Ragusa
- Centre for Genome Engineering and Maintenance (CenGEM), College of Health, Medicine and Life Sciences, Brunel University London, Kingston Lane, Uxbridge UB8 3PH, UK; (D.R.); (J.M.B.)
| | - Francesca Bruno
- Department of Biological, Geological, and Environmental Sciences, University of Catania, Via Androne 81, 95124 Catania, Italy; (C.F.); (F.B.); (S.S.)
| | - Salvatore Saccone
- Department of Biological, Geological, and Environmental Sciences, University of Catania, Via Androne 81, 95124 Catania, Italy; (C.F.); (F.B.); (S.S.)
| | - Joanna Mary Bridger
- Centre for Genome Engineering and Maintenance (CenGEM), College of Health, Medicine and Life Sciences, Brunel University London, Kingston Lane, Uxbridge UB8 3PH, UK; (D.R.); (J.M.B.)
| | - Sabrina Tosi
- Centre for Genome Engineering and Maintenance (CenGEM), College of Health, Medicine and Life Sciences, Brunel University London, Kingston Lane, Uxbridge UB8 3PH, UK; (D.R.); (J.M.B.)
- Leukaemia and Chromosome Research Laboratory, College of Health, Medicine and Life Sciences, Brunel University London, Kingston Lane, Uxbridge UB8 3PH, UK
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41
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Kawasaki K, Fukaya T. Regulatory landscape of enhancer-mediated transcriptional activation. Trends Cell Biol 2024:S0962-8924(24)00020-5. [PMID: 38355349 DOI: 10.1016/j.tcb.2024.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/21/2023] [Accepted: 01/22/2024] [Indexed: 02/16/2024]
Abstract
Enhancers are noncoding regulatory elements that instruct spatial and temporal specificity of gene transcription in response to a variety of intrinsic and extrinsic signals during development. Although it has long been postulated that enhancers physically interact with target promoters through the formation of stable loops, recent studies have changed this static view: sequence-specific transcription factors (TFs) and coactivators are dynamically recruited to enhancers and assemble so-called transcription hubs. Dynamic assembly of transcription hubs appears to serve as a key scaffold to integrate regulatory information encoded by surrounding genome and biophysical properties of transcription machineries. In this review, we outline emerging new models of transcriptional regulation by enhancers and discuss future perspectives.
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Affiliation(s)
- Koji Kawasaki
- Laboratory of Transcription Dynamics, Research Center for Biological Visualization, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Takashi Fukaya
- Laboratory of Transcription Dynamics, Research Center for Biological Visualization, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan; Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.
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42
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Hatzakis N, Kaestel-Hansen J, de Sautu M, Saminathan A, Scanavachi G, Correia R, Nielsen AJ, Bleshoey S, Boomsma W, Kirchhausen T. Deep learning assisted single particle tracking for automated correlation between diffusion and function. RESEARCH SQUARE 2024:rs.3.rs-3716053. [PMID: 38352328 PMCID: PMC10862944 DOI: 10.21203/rs.3.rs-3716053/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Sub-cellular diffusion in living systems reflects cellular processes and interactions. Recent advances in optical microscopy allow the tracking of this nanoscale diffusion of individual objects with an unprecedented level of precision. However, the agnostic and automated extraction of functional information from the diffusion of molecules and organelles within the sub-cellular environment, is labor-intensive and poses a significant challenge. Here we introduce DeepSPT, a deep learning framework to interpret the diffusional 2D or 3D temporal behavior of objects in a rapid and efficient manner, agnostically. Demonstrating its versatility, we have applied DeepSPT to automated mapping of the early events of viral infections, identifying distinct types of endosomal organelles, and clathrin-coated pits and vesicles with up to 95% accuracy and within seconds instead of weeks. The fact that DeepSPT effectively extracts biological information from diffusion alone illustrates that besides structure, motion encodes function at the molecular and subcellular level.
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43
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Hung TC, Kingsley DM, Boettiger AN. Boundary stacking interactions enable cross-TAD enhancer-promoter communication during limb development. Nat Genet 2024; 56:306-314. [PMID: 38238628 DOI: 10.1038/s41588-023-01641-2] [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: 02/06/2023] [Accepted: 12/06/2023] [Indexed: 02/15/2024]
Abstract
Although promoters and their enhancers are frequently contained within a topologically associating domain (TAD), some developmentally important genes have their promoter and enhancers within different TADs. Hypotheses about molecular mechanisms enabling cross-TAD interactions remain to be assessed. To test these hypotheses, we used optical reconstruction of chromatin architecture to characterize the conformations of the Pitx1 locus on single chromosomes in developing mouse limbs. Our data support a model in which neighboring boundaries are stacked as a result of loop extrusion, bringing boundary-proximal cis-elements into contact. This stacking interaction also contributes to the appearance of architectural stripes in the population average maps. Through molecular dynamics simulations, we found that increasing boundary strengths facilitates the formation of the stacked boundary conformation, counter-intuitively facilitating border bypass. This work provides a revised view of the TAD borders' function, both facilitating and preventing cis-regulatory interactions, and introduces a framework to distinguish border-crossing from border-respecting enhancer-promoter pairs.
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Affiliation(s)
- Tzu-Chiao Hung
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - David M Kingsley
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Alistair N Boettiger
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA.
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44
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Meeussen JVW, Lenstra TL. Time will tell: comparing timescales to gain insight into transcriptional bursting. Trends Genet 2024; 40:160-174. [PMID: 38216391 PMCID: PMC10860890 DOI: 10.1016/j.tig.2023.11.003] [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: 09/13/2023] [Revised: 11/27/2023] [Accepted: 11/27/2023] [Indexed: 01/14/2024]
Abstract
Recent imaging studies have captured the dynamics of regulatory events of transcription inside living cells. These events include transcription factor (TF) DNA binding, chromatin remodeling and modification, enhancer-promoter (E-P) proximity, cluster formation, and preinitiation complex (PIC) assembly. Together, these molecular events culminate in stochastic bursts of RNA synthesis, but their kinetic relationship remains largely unclear. In this review, we compare the timescales of upstream regulatory steps (input) with the kinetics of transcriptional bursting (output) to generate mechanistic models of transcription dynamics in single cells. We highlight open questions and potential technical advances to guide future endeavors toward a quantitative and kinetic understanding of transcription regulation.
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Affiliation(s)
- Joseph V W Meeussen
- Division of Gene Regulation, The Netherlands Cancer Institute, Oncode Institute, Amsterdam 1066CX, The Netherlands
| | - Tineke L Lenstra
- Division of Gene Regulation, The Netherlands Cancer Institute, Oncode Institute, Amsterdam 1066CX, The Netherlands.
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45
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Zhang Y, Boninsegna L, Yang M, Misteli T, Alber F, Ma J. Computational methods for analysing multiscale 3D genome organization. Nat Rev Genet 2024; 25:123-141. [PMID: 37673975 PMCID: PMC11127719 DOI: 10.1038/s41576-023-00638-1] [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] [Accepted: 07/12/2023] [Indexed: 09/08/2023]
Abstract
Recent progress in whole-genome mapping and imaging technologies has enabled the characterization of the spatial organization and folding of the genome in the nucleus. In parallel, advanced computational methods have been developed to leverage these mapping data to reveal multiscale three-dimensional (3D) genome features and to provide a more complete view of genome structure and its connections to genome functions such as transcription. Here, we discuss how recently developed computational tools, including machine-learning-based methods and integrative structure-modelling frameworks, have led to a systematic, multiscale delineation of the connections among different scales of 3D genome organization, genomic and epigenomic features, functional nuclear components and genome function. However, approaches that more comprehensively integrate a wide variety of genomic and imaging datasets are still needed to uncover the functional role of 3D genome structure in defining cellular phenotypes in health and disease.
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Affiliation(s)
- Yang Zhang
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Lorenzo Boninsegna
- Department of Microbiology, Immunology and Molecular Genetics and Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA, USA
| | - Muyu Yang
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Tom Misteli
- Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA.
| | - Frank Alber
- Department of Microbiology, Immunology and Molecular Genetics and Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA, USA.
| | - Jian Ma
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, USA.
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46
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Du M, Stitzinger SH, Spille JH, Cho WK, Lee C, Hijaz M, Quintana A, Cissé II. Direct observation of a condensate effect on super-enhancer controlled gene bursting. Cell 2024; 187:331-344.e17. [PMID: 38194964 DOI: 10.1016/j.cell.2023.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 10/29/2023] [Accepted: 12/04/2023] [Indexed: 01/11/2024]
Abstract
Enhancers are distal DNA elements believed to loop and contact promoters to control gene expression. Recently, we found diffraction-sized transcriptional condensates at genes controlled by clusters of enhancers (super-enhancers). However, a direct function of endogenous condensates in controlling gene expression remains elusive. Here, we develop live-cell super-resolution and multi-color 3D-imaging approaches to investigate putative roles of endogenous condensates in the regulation of super-enhancer controlled gene Sox2. In contrast to enhancer distance, we find instead that the condensate's positional dynamics are a better predictor of gene expression. A basal gene bursting occurs when the condensate is far (>1 μm), but burst size and frequency are enhanced when the condensate moves in proximity (<1 μm). Perturbations of cohesin and local DNA elements do not prevent basal bursting but affect the condensate and its burst enhancement. We propose a three-way kissing model whereby the condensate interacts transiently with gene locus and regulatory DNA elements to control gene bursting.
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Affiliation(s)
- Manyu Du
- Department of Biological Physics, Max Planck Institute for Immunobiology and Epigenetics, Freiburg im Breisgau, Baden-Württemberg 79108, Germany
| | - Simon Hendrik Stitzinger
- Department of Biological Physics, Max Planck Institute for Immunobiology and Epigenetics, Freiburg im Breisgau, Baden-Württemberg 79108, Germany
| | - Jan-Hendrik Spille
- Department of Biological Physics, Max Planck Institute for Immunobiology and Epigenetics, Freiburg im Breisgau, Baden-Württemberg 79108, Germany
| | - Won-Ki Cho
- Department of Biological Physics, Max Planck Institute for Immunobiology and Epigenetics, Freiburg im Breisgau, Baden-Württemberg 79108, Germany
| | - Choongman Lee
- Department of Biological Physics, Max Planck Institute for Immunobiology and Epigenetics, Freiburg im Breisgau, Baden-Württemberg 79108, Germany
| | - Mohammed Hijaz
- Department of Biological Physics, Max Planck Institute for Immunobiology and Epigenetics, Freiburg im Breisgau, Baden-Württemberg 79108, Germany
| | - Andrea Quintana
- Department of Biological Physics, Max Planck Institute for Immunobiology and Epigenetics, Freiburg im Breisgau, Baden-Württemberg 79108, Germany
| | - Ibrahim I Cissé
- Department of Biological Physics, Max Planck Institute for Immunobiology and Epigenetics, Freiburg im Breisgau, Baden-Württemberg 79108, Germany.
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47
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Hua D, Gu M, Zhang X, Du Y, Xie H, Qi L, Du X, Bai Z, Zhu X, Tian D. DiffDomain enables identification of structurally reorganized topologically associating domains. Nat Commun 2024; 15:502. [PMID: 38218905 PMCID: PMC10787792 DOI: 10.1038/s41467-024-44782-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 01/02/2024] [Indexed: 01/15/2024] Open
Abstract
Topologically associating domains (TADs) are critical structural units in three-dimensional genome organization of mammalian genome. Dynamic reorganizations of TADs between health and disease states are associated with essential genome functions. However, computational methods for identifying reorganized TADs are still in the early stages of development. Here, we present DiffDomain, an algorithm leveraging high-dimensional random matrix theory to identify structurally reorganized TADs using high-throughput chromosome conformation capture (Hi-C) contact maps. Method comparison using multiple real Hi-C datasets reveals that DiffDomain outperforms alternative methods for false positive rates, true positive rates, and identifying a new subtype of reorganized TADs. Applying DiffDomain to Hi-C data from different cell types and disease states demonstrates its biological relevance. Identified reorganized TADs are associated with structural variations and epigenomic changes such as changes in CTCF binding sites. By applying to a single-cell Hi-C data from mouse neuronal development, DiffDomain can identify reorganized TADs between cell types with reasonable reproducibility using pseudo-bulk Hi-C data from as few as 100 cells per condition. Moreover, DiffDomain reveals differential cell-to-population variability and heterogeneous cell-to-cell variability in TADs. Therefore, DiffDomain is a statistically sound method for better comparative analysis of TADs using both Hi-C and single-cell Hi-C data.
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Affiliation(s)
- Dunming Hua
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Ming Gu
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Xiao Zhang
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Yanyi Du
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Hangcheng Xie
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Li Qi
- Chongqing Municipal Center for Disease Control and Prevention, Chongqing, 400042, China
| | - Xiangjun Du
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Zhidong Bai
- KLASMOE & School of Mathematics and Statistics, Northeast Normal University, Changchun, Jilin, 130024, China
| | - Xiaopeng Zhu
- MyCellome LLC., Allison Park, PA, 15101, USA
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Dechao Tian
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China.
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China.
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48
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Hariprakash JM, Salviato E, La Mastra F, Sebestyén E, Tagliaferri I, Silva RS, Lucini F, Farina L, Cinquanta M, Rancati I, Riboni M, Minardi SP, Roz L, Gorini F, Lanzuolo C, Casola S, Ferrari F. Leveraging Tissue-Specific Enhancer-Target Gene Regulatory Networks Identifies Enhancer Somatic Mutations That Functionally Impact Lung Cancer. Cancer Res 2024; 84:133-153. [PMID: 37855660 PMCID: PMC10758689 DOI: 10.1158/0008-5472.can-23-1129] [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: 04/13/2023] [Revised: 08/29/2023] [Accepted: 10/17/2023] [Indexed: 10/20/2023]
Abstract
Enhancers are noncoding regulatory DNA regions that modulate the transcription of target genes, often over large distances along with the genomic sequence. Enhancer alterations have been associated with various pathological conditions, including cancer. However, the identification and characterization of somatic mutations in noncoding regulatory regions with a functional effect on tumorigenesis and prognosis remain a major challenge. Here, we present a strategy for detecting and characterizing enhancer mutations in a genome-wide analysis of patient cohorts, across three lung cancer subtypes. Lung tissue-specific enhancers were defined by integrating experimental data and public epigenomic profiles, and the genome-wide enhancer-target gene regulatory network of lung cells was constructed by integrating chromatin three-dimensional architecture data. Lung cancers possessed a similar mutation burden at tissue-specific enhancers and exons but with differences in their mutation signatures. Functionally relevant alterations were prioritized on the basis of the pathway-level integration of the effect of a mutation and the frequency of mutations on individual enhancers. The genes enriched for mutated enhancers converged on the regulation of key biological processes and pathways relevant to tumor biology. Recurrent mutations in individual enhancers also affected the expression of target genes, with potential relevance for patient prognosis. Together, these findings show that noncoding regulatory mutations have a potential relevance for cancer pathogenesis and can be exploited for patient classification. SIGNIFICANCE Mapping enhancer-target gene regulatory interactions and analyzing enhancer mutations at the level of their target genes and pathways reveal convergence of recurrent enhancer mutations on biological processes involved in tumorigenesis and prognosis.
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Affiliation(s)
| | - Elisa Salviato
- IFOM-ETS, the AIRC Institute of Molecular Oncology, Milan, Italy
| | | | - Endre Sebestyén
- IFOM-ETS, the AIRC Institute of Molecular Oncology, Milan, Italy
| | | | | | - Federica Lucini
- IFOM-ETS, the AIRC Institute of Molecular Oncology, Milan, Italy
| | - Lorenzo Farina
- IFOM-ETS, the AIRC Institute of Molecular Oncology, Milan, Italy
| | | | - Ilaria Rancati
- IFOM-ETS, the AIRC Institute of Molecular Oncology, Milan, Italy
| | | | | | - Luca Roz
- Fondazione IRCCS—Istituto Nazionale Tumori, Milan, Italy
| | - Francesca Gorini
- INGM, National Institute of Molecular Genetics “Romeo ed Enrica Invernizzi,” Milan, Italy
| | - Chiara Lanzuolo
- INGM, National Institute of Molecular Genetics “Romeo ed Enrica Invernizzi,” Milan, Italy
- Institute of Biomedical Technologies, National Research Council (ITB-CNR), Segrate, Italy
| | - Stefano Casola
- IFOM-ETS, the AIRC Institute of Molecular Oncology, Milan, Italy
| | - Francesco Ferrari
- IFOM-ETS, the AIRC Institute of Molecular Oncology, Milan, Italy
- Institute of Molecular Genetics “Luigi Luca Cavalli-Sforza,” National Research Council (IGM-CNR), Pavia, Italy
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49
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Papale A, Holcman D. Chromatin phase separated nanoregions explored by polymer cross-linker models and reconstructed from single particle trajectories. PLoS Comput Biol 2024; 20:e1011794. [PMID: 38266036 PMCID: PMC10843633 DOI: 10.1371/journal.pcbi.1011794] [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: 03/25/2023] [Revised: 02/05/2024] [Accepted: 01/01/2024] [Indexed: 01/26/2024] Open
Abstract
Phase separated domains (PSDs) are ubiquitous in cell biology, representing nanoregions of high molecular concentration. PSDs appear at diverse cellular domains, such as neuronal synapses but also in eukaryotic cell nucleus, limiting the access of transcription factors and thus preventing gene expression. We develop a generalized cross-linker polymer model, to study PSDs: we show that increasing the number of cross-linkers induces a polymer condensation, preventing access of diffusing molecules. To investigate how the PSDs restrict the motion of diffusing molecules, we compute the mean residence and first escaping times. Finally, we develop a method based on mean-square-displacement of single particle trajectories to reconstruct the properties of PSDs from the continuum range of anomalous exponents. We also show here that PSD generated by polymers do not induces a long-range attracting field (potential well), in contrast with nanodomains at neuronal synapses. To conclude, PSDs can result from condensed chromatin organization, where the number of cross-linkers controls molecular access.
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Affiliation(s)
- Andrea Papale
- Group of Computational Biology and Applied Mathemathics, Ecole Normale Supérieure, IBENS, Université PSL, Paris, France
| | - David Holcman
- Group of Computational Biology and Applied Mathemathics, Ecole Normale Supérieure, IBENS, Université PSL, Paris, France
- Churchill College, University of Cambridge, United Kingdom
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González-Acosta D, Lopes M. DNA replication and replication stress response in the context of nuclear architecture. Chromosoma 2024; 133:57-75. [PMID: 38055079 PMCID: PMC10904558 DOI: 10.1007/s00412-023-00813-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 12/07/2023]
Abstract
The DNA replication process needs to be coordinated with other DNA metabolism transactions and must eventually extend to the full genome, regardless of chromatin status, gene expression, secondary structures and DNA lesions. Completeness and accuracy of DNA replication are crucial to maintain genome integrity, limiting transformation in normal cells and offering targeting opportunities for proliferating cancer cells. DNA replication is thus tightly coordinated with chromatin dynamics and 3D genome architecture, and we are only beginning to understand the underlying molecular mechanisms. While much has recently been discovered on how DNA replication initiation is organised and modulated in different genomic regions and nuclear territories-the so-called "DNA replication program"-we know much less on how the elongation of ongoing replication forks and particularly the response to replication obstacles is affected by the local nuclear organisation. Also, it is still elusive how specific components of nuclear architecture participate in the replication stress response. Here, we review known mechanisms and factors orchestrating replication initiation, and replication fork progression upon stress, focusing on recent evidence linking genome organisation and nuclear architecture with the cellular responses to replication interference, and highlighting open questions and future challenges to explore this exciting new avenue of research.
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Affiliation(s)
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland.
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