1
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Logeman BL, Grieco SF, Holmes TC, Xu X. Unfolding neural diversity: how dynamic three-dimensional genome architecture regulates brain function and disease. Mol Psychiatry 2025:10.1038/s41380-025-03056-3. [PMID: 40410418 DOI: 10.1038/s41380-025-03056-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2025] [Revised: 05/01/2025] [Accepted: 05/12/2025] [Indexed: 05/25/2025]
Abstract
The advent of single cell multi-omic technologies has ushered in a revolution in how we study the impact of three-dimensional genome organization on brain cellular composition and function. Transcriptomic and epigenomic studies reveal enormous cellular diversity that is present in mammalian nervous systems, raising the question, "how does this diversity arise and for what is its use?" Advances in the field of three-dimensional nuclear architecture have illuminated our understanding of how genome folding gives rise to dynamic gene expression programs important in healthy brain function and in disease. In this review we highlight recent work defining how neuronal identity, maturation, and plasticity are shaped by genome architecture. We discuss how newly identified genetic variations influence genome architecture and contribute to the evolution of species-unique neuronal and behavioral functional traits. We include examples for both humans and model organisms in which maladaptive genomic architecture is a causal agent in disease. Finally, we make conclusions and address future perspectives of dynamic three-dimensional genome (4D nucelome) research.
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Affiliation(s)
- Brandon L Logeman
- Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Steven F Grieco
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA, 92697, USA
- Center for Neural Circuit Mapping, University of California, Irvine, CA, USA
| | - Todd C Holmes
- Center for Neural Circuit Mapping, University of California, Irvine, CA, USA
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA, 92697, USA.
- Center for Neural Circuit Mapping, University of California, Irvine, CA, USA.
- Department of Microbiology and Molecular Genetics, University of California, Irvine, CA, USA.
- Department of Biomedical Engineering, University of California, Irvine, CA, USA.
- Department of Computer Science, University of California, Irvine, CA, USA.
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2
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Chen L, Zhang Z, Wang Z, Hong L, Wang H, Zhang J. Barrier effects on the kinetics of cohesin-mediated loop extrusion. Biophys J 2025; 124:1462-1477. [PMID: 40181539 DOI: 10.1016/j.bpj.2025.03.026] [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: 10/22/2024] [Revised: 01/23/2025] [Accepted: 03/26/2025] [Indexed: 04/05/2025] Open
Abstract
Chromosome organization mediated by structural maintenance of chromosome complexes is crucial in many organisms. Cohesin extrudes chromatin into loops that are thought to lengthen until it is obstructed by CTCF proteins. In complex cellular environments, the loop extrusion machinery may encounter other chromatin-binding proteins. How these proteins interfere with the cohesin-meditated extrusion process is largely unexplored, but recent experiments have shown that some proteins serve as physical barriers that block cohesin translocation. Other proteins containing a cohesin-interaction motif serve as chemical barriers to induce cohesin pausing through interactions with it. Here, we develop an analytically solvable approach for the loop extrusion model incorporating barriers to investigate the effect of the barrier on the passive extrusion process. To further quantify the impact of barriers, we calculate the mean looping time it takes for cohesin to translocate to form a stable loop before dissociation. Our finding reveals that the physical barrier can accelerate the loop formation, and the degree of acceleration is closely related to the impedance strength of the physical barrier. In particular, the synergy of the cohesin loading site and the physical barrier site accelerates loop formation more significantly. The proximity of the cohesin loading site to the barrier site facilitates the rapid formation of stable loops in long genomes, which implies loop extrusion and chromatin-binding proteins might shape functional genomic organization. Conversely, chemical barriers consistently impede loop formation, with increasing impedance strength of the chemical barrier leading to longer loop formation time. Our study contributes to a more comprehensive understanding of the complexity of the loop extrusion process, providing a new perspective on the potential mechanisms of gene regulation.
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Affiliation(s)
- Leiyan Chen
- Guangdong Province Key Laboratory of Computational Science, Sun Yat-sen University, Guangzhou 510275, P.R. China; School of Mathematics, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Zhenquan Zhang
- Guangdong Province Key Laboratory of Computational Science, Sun Yat-sen University, Guangzhou 510275, P.R. China; School of Mathematics, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Zihao Wang
- Guangdong Province Key Laboratory of Computational Science, Sun Yat-sen University, Guangzhou 510275, P.R. China; School of Mathematics, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Liu Hong
- School of Mathematics, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Haohua Wang
- School of Mathematics and Statistics, Hainan University, Haikou 570228, P.R. China.
| | - Jiajun Zhang
- Guangdong Province Key Laboratory of Computational Science, Sun Yat-sen University, Guangzhou 510275, P.R. China; School of Mathematics, Sun Yat-sen University, Guangzhou 510275, P.R. China.
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3
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Murayama Y. Sister chromatid cohesion through the lens of biochemical experiments. Curr Opin Cell Biol 2025; 93:102464. [PMID: 39879903 DOI: 10.1016/j.ceb.2025.102464] [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: 09/30/2024] [Revised: 12/29/2024] [Accepted: 01/06/2025] [Indexed: 01/31/2025]
Abstract
Faithful chromosome segregation in eukaryotes relies on physical cohesion between newly duplicated sister chromatids. Cohesin is a ring-shaped ATPase assembly that mediates sister chromatid cohesion through its ability to topologically entrap DNA. Cohesin, assisted by several regulatory proteins, binds to DNA prior to DNA replication and then holds two sister DNAs together when it encounters the replication machinery. Cohesion establishment further requires cohesin acetylation, which confers near eternal stability on chromatin-bound cohesin until the onset of chromosome segregation. In addition to a wealth of experimental evidence from cellular studies, recent advances in reconstitution approaches are now beginning to unravel the biochemical properties of cohesin that underlie its function in sister chromatid cohesion. This review summarizes recent insights into the mechanism of cohesion establishment.
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Affiliation(s)
- Yasuto Murayama
- Department of Chromosome Science, National Institute of Genetics, Mishima, 411-8540, Japan; Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Mishima, 411-8540, Japan.
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4
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Dasgupta M, Guha S, Armbruster L, Das D, Mitra MK. Nature of barriers determines first passage times in heterogeneous media. SOFT MATTER 2024; 20:8353-8362. [PMID: 39318347 DOI: 10.1039/d4sm00908h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2024]
Abstract
Intuition suggests that passage times across a region increase with the number of barriers along the path. Can this fail depending on the nature of the barrier? To probe this fundamental question, we exactly solve for the first passage time in general d-dimensions for diffusive transport through a spatially patterned array of obstacles - either entropic or energetic, depending on the nature of the obstacles. For energetic barriers, we show that first passage times vary non-monotonically with the number of barriers, while for entropic barriers it increases monotonically. This non-monotonicity for energetic barriers is further reflected in the behaviour of effective diffusivity as well. We then design a simple experiment where a robotic bug navigates in a heterogeneous environment through a spatially patterned array of obstacles to validate our predictions. Finally, using numerical simulations, we show that this non-monotonic behaviour for energetic barriers is general and extends to even super-diffusive transport.
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Affiliation(s)
| | - Sougata Guha
- Department of Physics, IIT Bombay, Mumbai 400076, India.
- INFN Napoli, Complesso Universitario di Monte S. Angelo, 80126 Napoli, Italy
| | | | - Dibyendu Das
- Department of Physics, IIT Bombay, Mumbai 400076, India.
| | - Mithun K Mitra
- Department of Physics, IIT Bombay, Mumbai 400076, India.
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5
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Spector B, Santana J, Pufall M, Price D. DFF-ChIP: a method to detect and quantify complex interactions between RNA polymerase II, transcription factors, and chromatin. Nucleic Acids Res 2024; 52:e88. [PMID: 39248105 PMCID: PMC11472042 DOI: 10.1093/nar/gkae760] [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: 12/22/2023] [Revised: 07/30/2024] [Accepted: 08/20/2024] [Indexed: 09/10/2024] Open
Abstract
Recently, we introduced a chromatin immunoprecipitation (ChIP) technique utilizing the human DNA Fragmentation Factor (DFF) to digest the DNA prior to immunoprecipitation (DFF-ChIP) that provides the precise location of transcription complexes and their interactions with neighboring nucleosomes. Here we expand the technique to new targets and provide useful information concerning purification of DFF, digestion conditions, and the impact of crosslinking. DFF-ChIP analysis was performed individually for subunits of Mediator, DSIF, and NELF that that do not interact with DNA directly, but rather interact with RNA polymerase II (Pol II). We found that Mediator was associated almost exclusively with preinitiation complexes (PICs). DSIF and NELF were associated with engaged Pol II and, in addition, potential intermediates between PICs and early initiation complexes. DFF-ChIP was then used to analyze the occupancy of a tight binding transcription factor, CTCF, and a much weaker binding factor, glucocorticoid receptor (GR), with and without crosslinking. These results were compared to those from standard ChIP-Seq that employs sonication and to CUT&RUN which utilizes MNase to fragment the genomic DNA. Our findings indicate that DFF-ChIP reveals details of occupancy that are not available using other methods including information revealing pertinent protein:protein interactions.
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Affiliation(s)
- Benjamin M Spector
- Department of Biochemistry and Molecular Biology, The University of Iowa, Iowa City, IA 52242, USA
| | - Juan F Santana
- Department of Biochemistry and Molecular Biology, The University of Iowa, Iowa City, IA 52242, USA
| | - Miles A Pufall
- Department of Biochemistry and Molecular Biology, The University of Iowa, Iowa City, IA 52242, USA
| | - David H Price
- Department of Biochemistry and Molecular Biology, The University of Iowa, Iowa City, IA 52242, USA
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6
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Patel R, Pham K, Chandrashekar H, Phillips-Cremins JE. FISHnet: Detecting chromatin domains in single-cell sequential Oligopaints imaging data. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.18.599627. [PMID: 38948824 PMCID: PMC11212945 DOI: 10.1101/2024.06.18.599627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Sequential Oligopaints DNA FISH is an imaging technique that measures higher-order genome folding at single-allele resolution via multiplexed, probe-based tracing. Currently there is a paucity of algorithms to identify 3D genome features in sequential Oligopaints data. Here, we present FISHnet, a graph theory method based on optimization of network modularity to detect chromatin domains and boundaries in pairwise distance matrices. FISHnet uncovers cell type-specific domain-like folding patterns on single alleles, thus enabling future studies aiming to elucidate the role for single-cell folding variation on genome function.
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Affiliation(s)
- Rohan Patel
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA
- Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania
| | - Kenneth Pham
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA
- Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania
| | - Harshini Chandrashekar
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA
- Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania
| | - Jennifer E Phillips-Cremins
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA
- Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania
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7
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Rudnizky S, Murray PJ, Wolfe CH, Ha T. Single-Macromolecule Studies of Eukaryotic Genomic Maintenance. Annu Rev Phys Chem 2024; 75:209-230. [PMID: 38382570 DOI: 10.1146/annurev-physchem-090722-010601] [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: 02/23/2024]
Abstract
Genomes are self-organized and self-maintained as long, complex macromolecules of chromatin. The inherent heterogeneity, stochasticity, phase separation, and chromatin dynamics of genome operation make it challenging to study genomes using ensemble methods. Various single-molecule force-, fluorescent-, and sequencing-based techniques rooted in different disciplines have been developed to fill critical gaps in the capabilities of bulk measurements, each providing unique, otherwise inaccessible, insights into the structure and maintenance of the genome. Capable of capturing molecular-level details about the organization, conformational changes, and packaging of genetic material, as well as processive and stochastic movements of maintenance factors, a single-molecule toolbox provides an excellent opportunity for collaborative research to understand how genetic material functions in health and malfunctions in disease. In this review, we discuss novel insights brought to genomic sciences by single-molecule techniques and their potential to continue to revolutionize the field-one molecule at a time.
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Affiliation(s)
- Sergei Rudnizky
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peter J Murray
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, USA;
| | - Clara H Wolfe
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, USA;
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
- Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts, USA
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8
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Kant A, Guo Z, Vinayak V, Neguembor MV, Li WS, Agrawal V, Pujadas E, Almassalha L, Backman V, Lakadamyali M, Cosma MP, Shenoy VB. Active transcription and epigenetic reactions synergistically regulate meso-scale genomic organization. Nat Commun 2024; 15:4338. [PMID: 38773126 PMCID: PMC11109243 DOI: 10.1038/s41467-024-48698-z] [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: 04/24/2023] [Accepted: 05/06/2024] [Indexed: 05/23/2024] Open
Abstract
In interphase nuclei, chromatin forms dense domains of characteristic sizes, but the influence of transcription and histone modifications on domain size is not understood. We present a theoretical model exploring this relationship, considering chromatin-chromatin interactions, histone modifications, and chromatin extrusion. We predict that the size of heterochromatic domains is governed by a balance among the diffusive flux of methylated histones sustaining them and the acetylation reactions in the domains and the process of loop extrusion via supercoiling by RNAPII at their periphery, which contributes to size reduction. Super-resolution and nano-imaging of five distinct cell lines confirm the predictions indicating that the absence of transcription leads to larger heterochromatin domains. Furthermore, the model accurately reproduces the findings regarding how transcription-mediated supercoiling loss can mitigate the impacts of excessive cohesin loading. Our findings shed light on the role of transcription in genome organization, offering insights into chromatin dynamics and potential therapeutic targets.
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Affiliation(s)
- Aayush Kant
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Zixian Guo
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Vinayak Vinayak
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Maria Victoria Neguembor
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003, Barcelona, Spain
| | - Wing Shun Li
- Department of Applied Physics, Northwestern University, Evanston, IL, 60208, USA
- Center for Physical Genomics and Engineering, Northwestern University, Evanston, IL, 60202, USA
| | - Vasundhara Agrawal
- Center for Physical Genomics and Engineering, Northwestern University, Evanston, IL, 60202, USA
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Emily Pujadas
- Center for Physical Genomics and Engineering, Northwestern University, Evanston, IL, 60202, USA
| | - Luay Almassalha
- Center for Physical Genomics and Engineering, Northwestern University, Evanston, IL, 60202, USA
- Department of Gastroenterology and Hepatology, Northwestern Memorial Hospital, Chicago, IL, 60611, USA
| | - Vadim Backman
- Center for Physical Genomics and Engineering, Northwestern University, Evanston, IL, 60202, USA
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Melike Lakadamyali
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Maria Pia Cosma
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003, Barcelona, Spain
- ICREA, Barcelona, 08010, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, 08003, Spain
| | - Vivek B Shenoy
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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9
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Raimer Young HM, Hou PC, Bartosik AR, Atkin N, Wang L, Wang Z, Ratan A, Zang C, Wang YH. DNA fragility at topologically associated domain boundaries is promoted by alternative DNA secondary structure and topoisomerase II activity. Nucleic Acids Res 2024; 52:3837-3855. [PMID: 38452213 PMCID: PMC11040008 DOI: 10.1093/nar/gkae164] [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: 08/15/2023] [Revised: 02/03/2024] [Accepted: 02/23/2024] [Indexed: 03/09/2024] Open
Abstract
CCCTC-binding factor (CTCF) binding sites are hotspots of genome instability. Although many factors have been associated with CTCF binding site fragility, no study has integrated all fragility-related factors to understand the mechanism(s) of how they work together. Using an unbiased, genome-wide approach, we found that DNA double-strand breaks (DSBs) are enriched at strong, but not weak, CTCF binding sites in five human cell types. Energetically favorable alternative DNA secondary structures underlie strong CTCF binding sites. These structures coincided with the location of topoisomerase II (TOP2) cleavage complex, suggesting that DNA secondary structure acts as a recognition sequence for TOP2 binding and cleavage at CTCF binding sites. Furthermore, CTCF knockdown significantly increased DSBs at strong CTCF binding sites and at CTCF sites that are located at topologically associated domain (TAD) boundaries. TAD boundary-associated CTCF sites that lost CTCF upon knockdown displayed increased DSBs when compared to the gained sites, and those lost sites are overrepresented with G-quadruplexes, suggesting that the structures act as boundary insulators in the absence of CTCF, and contribute to increased DSBs. These results model how alternative DNA secondary structures facilitate recruitment of TOP2 to CTCF binding sites, providing mechanistic insight into DNA fragility at CTCF binding sites.
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Affiliation(s)
- Heather M Raimer Young
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908-0733, USA
| | - Pei-Chi Hou
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908-0733, USA
| | - Anna R Bartosik
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908-0733, USA
| | - Naomi D Atkin
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908-0733, USA
| | - Lixin Wang
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | - Zhenjia Wang
- Center for Public Health Genomics, University of Virginia School of Medicine, Charlottesville, VA 22908-0717, USA
| | - Aakrosh Ratan
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908-0733, USA
- Center for Public Health Genomics, University of Virginia School of Medicine, Charlottesville, VA 22908-0717, USA
- Department of Public Health Sciences, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- University of Virginia Comprehensive Cancer Center, Charlottesville, VA 22908, USA
| | - Chongzhi Zang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908-0733, USA
- Center for Public Health Genomics, University of Virginia School of Medicine, Charlottesville, VA 22908-0717, USA
- Department of Public Health Sciences, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- University of Virginia Comprehensive Cancer Center, Charlottesville, VA 22908, USA
| | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908-0733, USA
- University of Virginia Comprehensive Cancer Center, Charlottesville, VA 22908, USA
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10
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Cameron G, Gruszka D, Xie S, Kaya Ç, Nasmyth KA, Srinivasan M, Yardimci H. Sister chromatid cohesion establishment during DNA replication termination. Science 2024; 384:119-124. [PMID: 38484038 PMCID: PMC7615807 DOI: 10.1126/science.adf0224] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 02/27/2024] [Indexed: 04/06/2024]
Abstract
Newly copied sister chromatids are tethered together by the cohesin complex, but how sister chromatid cohesion coordinates with DNA replication is poorly understood. Prevailing models suggest that cohesin complexes, bound to DNA before replication, remain behind the advancing replication fork to keep sister chromatids together. By visualizing single replication forks colliding with preloaded cohesin complexes, we find that the replisome instead pushes cohesin to where a converging replisome is met. Whereas the converging replisomes are removed during DNA replication termination, cohesin remains on nascent DNA and provides cohesion. Additionally, we show that CMG (CDC45-MCM2-7-GINS) helicase disassembly during replication termination is vital for proper cohesion in budding yeast. Together, our results support a model wherein sister chromatid cohesion is established during DNA replication termination.
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Affiliation(s)
| | | | - Sherry Xie
- The Francis Crick Institute; London, United Kingdom
| | - Çağla Kaya
- The Francis Crick Institute; London, United Kingdom
| | - Kim A Nasmyth
- Department of Biochemistry, University of Oxford; Oxford, United Kingdom
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11
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Golov AK, Gavrilov AA. Cohesin-Dependent Loop Extrusion: Molecular Mechanics and Role in Cell Physiology. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:601-625. [PMID: 38831499 DOI: 10.1134/s0006297924040023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 12/29/2023] [Accepted: 02/15/2024] [Indexed: 06/05/2024]
Abstract
The most prominent representatives of multisubunit SMC complexes, cohesin and condensin, are best known as structural components of mitotic chromosomes. It turned out that these complexes, as well as their bacterial homologues, are molecular motors, the ATP-dependent movement of these complexes along DNA threads leads to the formation of DNA loops. In recent years, we have witnessed an avalanche-like accumulation of data on the process of SMC dependent DNA looping, also known as loop extrusion. This review briefly summarizes the current understanding of the place and role of cohesin-dependent extrusion in cell physiology and presents a number of models describing the potential molecular mechanism of extrusion in a most compelling way. We conclude the review with a discussion of how the capacity of cohesin to extrude DNA loops may be mechanistically linked to its involvement in sister chromatid cohesion.
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Affiliation(s)
- Arkadiy K Golov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
- Technion - Israel Institute of Technology, Haifa, 3525433, Israel
| | - Alexey A Gavrilov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
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12
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Golov AK, Gavrilov AA. Cohesin Complex: Structure and Principles of Interaction with DNA. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:585-600. [PMID: 38831498 DOI: 10.1134/s0006297924040011] [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: 10/14/2023] [Revised: 02/19/2024] [Accepted: 02/23/2024] [Indexed: 06/05/2024]
Abstract
Accurate duplication and separation of long linear genomic DNA molecules is associated with a number of purely mechanical problems. SMC complexes are key components of the cellular machinery that ensures decatenation of sister chromosomes and compaction of genomic DNA during division. Cohesin, one of the essential eukaryotic SMC complexes, has a typical ring structure with intersubunit pore through which DNA molecules can be threaded. Capacity of cohesin for such topological entrapment of DNA is crucial for the phenomenon of post-replicative association of sister chromatids better known as cohesion. Recently, it became apparent that cohesin and other SMC complexes are, in fact, motor proteins with a very peculiar movement pattern leading to formation of DNA loops. This specific process has been called loop extrusion. Extrusion underlies multiple functions of cohesin beyond cohesion, but molecular mechanism of the process remains a mystery. In this review, we summarized the data on molecular architecture of cohesin, effect of ATP hydrolysis cycle on this architecture, and known modes of cohesin-DNA interactions. Many of the seemingly disparate facts presented here will probably be incorporated in a unified mechanistic model of loop extrusion in the not-so-distant future.
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Affiliation(s)
- Arkadiy K Golov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
- Technion - Israel Institute of Technology, Haifa, 3525433, Israel
| | - Alexey A Gavrilov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
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13
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Murayama Y, Endo S, Kurokawa Y, Kurita A, Iwasaki S, Araki H. Coordination of cohesin and DNA replication observed with purified proteins. Nature 2024; 626:653-660. [PMID: 38267580 DOI: 10.1038/s41586-023-07003-6] [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: 05/15/2023] [Accepted: 12/19/2023] [Indexed: 01/26/2024]
Abstract
Two newly duplicated copies of genomic DNA are held together by the ring-shaped cohesin complex to ensure faithful inheritance of the genome during cell division1-3. Cohesin mediates sister chromatid cohesion by topologically entrapping two sister DNAs during DNA replication4,5, but how cohesion is established at the replication fork is poorly understood. Here, we studied the interplay between cohesin and replication by reconstituting a functional replisome using purified proteins. Once DNA is encircled before replication, the cohesin ring accommodates replication in its entirety, from initiation to termination, leading to topological capture of newly synthesized DNA. This suggests that topological cohesin loading is a critical molecular prerequisite to cope with replication. Paradoxically, topological loading per se is highly rate limiting and hardly occurs under the replication-competent physiological salt concentration. This inconsistency is resolved by the replisome-associated cohesion establishment factors Chl1 helicase and Ctf4 (refs. 6,7), which promote cohesin loading specifically during continuing replication. Accordingly, we found that bubble DNA, which mimics the state of DNA unwinding, induces topological cohesin loading and this is further promoted by Chl1. Thus, we propose that cohesin converts the initial electrostatic DNA-binding mode to a topological embrace when it encounters unwound DNA structures driven by enzymatic activities including replication. Together, our results show how cohesin initially responds to replication, and provide a molecular model for the establishment of sister chromatid cohesion.
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Affiliation(s)
- Yasuto Murayama
- Department of Chromosome Science, National Institute of Genetics, Mishima, Japan.
- Department of Genetics, Graduate University for Advanced Studies (SOUKENDAI), Mishima, Japan.
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Japan.
| | - Shizuko Endo
- Department of Chromosome Science, National Institute of Genetics, Mishima, Japan
| | - Yumiko Kurokawa
- Department of Chromosome Science, National Institute of Genetics, Mishima, Japan
- Department of Genetics, Graduate University for Advanced Studies (SOUKENDAI), Mishima, Japan
| | - Ayako Kurita
- Department of Chromosome Science, National Institute of Genetics, Mishima, Japan
| | - Sanae Iwasaki
- Department of Chromosome Science, National Institute of Genetics, Mishima, Japan
| | - Hiroyuki Araki
- Department of Chromosome Science, National Institute of Genetics, Mishima, Japan
- Joint Support-Centre for Data Science Research, Research Organisation of Information and Systems, Tachikawa, Japan
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14
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Wang C, Manders F, Groh L, Oldenkamp R, Logie C. Corticosteroid-induced chromatin loop dynamics at the FKBP5 gene. Ann N Y Acad Sci 2023; 1529:109-119. [PMID: 37796452 DOI: 10.1111/nyas.15064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
FKBP5 is a 115-kb-long glucocorticoid-inducible gene implicated in psychiatric disorders. To investigate the complexities of chromatin interaction frequencies at the FKBP5 topologically associated domain (TAD), we deployed 15 one-to-all chromatin capture viewpoints near gene promoters, enhancers, introns, and CTCF-loop anchors. This revealed a "one-TAD-one-gene" structure encompassing the FKBP5 promoter and its enhancers. The FKBP5 promoter and its two glucocorticoid-stimulated enhancers roam the entire TAD while displaying subtle cell type-specific interactomes. The FKBP5 TAD consists of two nested CTCF loops that are coordinated by one CTCF site in the eighth intron of FKBP5 and another beyond its polyadenylation site, 61 kb further. Loop extension correlates with transcription increases through the intronic CTCF site. This is efficiently compensated for, since the short loop is restored even under high transcription regimes. The boundaries of the FKBP5 TAD consist of divergent CTCF site patterns, harbor multiple smaller genes, and are resilient to glucocorticoid stimulation. Interestingly, both FKBP5 TAD boundaries harbor H3K27me3-marked heterochromatin blocks that may reinforce them. We propose that cis-acting genetic and epigenetic polymorphisms underlying FKBP5 expression variation are likely to reside within a 240-kb region that consists of the FKBP5 TAD, its left sub-TAD, and both its boundaries.
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Affiliation(s)
- Cheng Wang
- Department of Molecular Biology, Radboud Institute for Molecular Science, Faculty of Science, Radboud University, Nijmegen, The Netherlands
| | - Freek Manders
- Department of Molecular Biology, Radboud Institute for Molecular Science, Faculty of Science, Radboud University, Nijmegen, The Netherlands
- Gendx, Utrecht, The Netherlands
| | - Laszlo Groh
- Department of Molecular Biology, Radboud Institute for Molecular Science, Faculty of Science, Radboud University, Nijmegen, The Netherlands
- Department of Molecular Cell Biology and Immunology, Amsterdam UMC, Amsterdam, The Netherlands
| | - Roel Oldenkamp
- Department of Molecular Biology, Radboud Institute for Molecular Science, Faculty of Science, Radboud University, Nijmegen, The Netherlands
- Division of Cell Biology, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Colin Logie
- Department of Molecular Biology, Radboud Institute for Molecular Science, Faculty of Science, Radboud University, Nijmegen, The Netherlands
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15
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Yabushita T, Chinen T, Nishiyama A, Asada S, Shimura R, Isobe T, Yamamoto K, Sato N, Enomoto Y, Tanaka Y, Fukuyama T, Satoh H, Kato K, Saitoh K, Ishikawa T, Soga T, Nannya Y, Fukagawa T, Nakanishi M, Kitagawa D, Kitamura T, Goyama S. Mitotic perturbation is a key mechanism of action of decitabine in myeloid tumor treatment. Cell Rep 2023; 42:113098. [PMID: 37714156 DOI: 10.1016/j.celrep.2023.113098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 06/22/2023] [Accepted: 08/21/2023] [Indexed: 09/17/2023] Open
Abstract
Decitabine (DAC) is clinically used to treat myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Our genome-wide CRISPR-dCas9 activation screen using MDS-derived AML cells indicates that mitotic regulation is critical for DAC resistance. DAC strongly induces abnormal mitosis (abscission failure or tripolar mitosis) in human myeloid tumors at clinical concentrations, especially in those with TP53 mutations or antecedent hematological disorders. This DAC-induced mitotic disruption and apoptosis are significantly attenuated in DNMT1-depleted cells. In contrast, overexpression of Dnmt1, but not the catalytically inactive mutant, enhances DAC-induced mitotic defects in myeloid tumors. We also demonstrate that DAC-induced mitotic disruption is enhanced by pharmacological inhibition of the ATR-CLSPN-CHK1 pathway. These data challenge the current assumption that DAC inhibits leukemogenesis through DNMT1 inhibition and subsequent DNA hypomethylation and highlight the potent activity of DAC to disrupt mitosis through aberrant DNMT1-DNA covalent bonds.
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Affiliation(s)
- Tomohiro Yabushita
- Division of Cellular Therapy, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Takumi Chinen
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Atsuya Nishiyama
- Division of Cancer Cell Biology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Shuhei Asada
- Division of Cellular Therapy, Institute of Medical Science, The University of Tokyo, Tokyo, Japan; The Institute of Laboratory Animals, Tokyo Women's Medical University, Tokyo, Japan
| | - Ruka Shimura
- Division of Molecular Oncology, Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Tomoya Isobe
- Division of Molecular Oncology, Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan; Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Keita Yamamoto
- Division of Molecular Oncology, Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Naru Sato
- Division of Cellular Therapy, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Yutaka Enomoto
- Division of Cellular Therapy, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Yosuke Tanaka
- Division of Cellular Therapy, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Tomofusa Fukuyama
- Division of Cellular Therapy, Institute of Medical Science, The University of Tokyo, Tokyo, Japan; Department of Hematology, International University of Health and Welfare Hospital, Tochigi, Japan
| | - Hitoshi Satoh
- Division of Medical Genome Sciences, Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Keiko Kato
- Infinity Lab, INC, Yamagata, Japan; Institute for Advanced Biosciences, Keio University, Yamagata, Japan
| | - Kaori Saitoh
- Infinity Lab, INC, Yamagata, Japan; Institute for Advanced Biosciences, Keio University, Yamagata, Japan
| | - Takamasa Ishikawa
- Infinity Lab, INC, Yamagata, Japan; Institute for Advanced Biosciences, Keio University, Yamagata, Japan
| | - Tomoyoshi Soga
- Institute for Advanced Biosciences, Keio University, Yamagata, Japan
| | - Yasuhito Nannya
- Division of Hematopoietic Disease Control, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Tatsuo Fukagawa
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Makoto Nakanishi
- Division of Cancer Cell Biology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Daiju Kitagawa
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Toshio Kitamura
- Division of Cellular Therapy, Institute of Medical Science, The University of Tokyo, Tokyo, Japan; Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Hyogo, Japan
| | - Susumu Goyama
- Division of Molecular Oncology, Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan.
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16
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Litwin I, Nowicka M, Markowska K, Maciaszczyk-Dziubińska E, Tomaszewska P, Wysocki R, Kramarz K. ISW1a modulates cohesin distribution in centromeric and pericentromeric regions. Nucleic Acids Res 2023; 51:9101-9121. [PMID: 37486771 PMCID: PMC10516642 DOI: 10.1093/nar/gkad612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 06/28/2023] [Accepted: 07/11/2023] [Indexed: 07/25/2023] Open
Abstract
Cohesin is a highly conserved, multiprotein complex whose canonical function is to hold sister chromatids together to ensure accurate chromosome segregation. Cohesin association with chromatin relies on the Scc2-Scc4 cohesin loading complex that enables cohesin ring opening and topological entrapment of sister DNAs. To better understand how sister chromatid cohesion is regulated, we performed a proteomic screen in budding yeast that identified the Isw1 chromatin remodeler as a cohesin binding partner. In addition, we found that Isw1 also interacts with Scc2-Scc4. Lack of Isw1 protein, the Ioc3 subunit of ISW1a or Isw1 chromatin remodeling activity resulted in increased accumulation of cohesin at centromeres and pericentromeres, suggesting that ISW1a may promote efficient translocation of cohesin from the centromeric site of loading to neighboring regions. Consistent with the role of ISW1a in the chromatin organization of centromeric regions, Isw1 was found to be recruited to centromeres. In its absence we observed changes in the nucleosomal landscape at centromeres and pericentromeres. Finally, we discovered that upon loss of RSC functionality, ISW1a activity leads to reduced cohesin binding and cohesion defect. Taken together, our results support the notion of a key role of chromatin remodelers in the regulation of cohesin distribution on chromosomes.
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Affiliation(s)
- Ireneusz Litwin
- Academic Excellence Hub - Research Centre for DNA Repair and Replication, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland
| | - Małgorzata Nowicka
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland
| | - Katarzyna Markowska
- Academic Excellence Hub - Research Centre for DNA Repair and Replication, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland
| | - Ewa Maciaszczyk-Dziubińska
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland
| | - Paulina Tomaszewska
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Robert Wysocki
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland
| | - Karol Kramarz
- Academic Excellence Hub - Research Centre for DNA Repair and Replication, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland
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17
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Irvin EM, Wang H. Single-molecule imaging of genome maintenance proteins encountering specific DNA sequences and structures. DNA Repair (Amst) 2023; 128:103528. [PMID: 37392578 PMCID: PMC10989508 DOI: 10.1016/j.dnarep.2023.103528] [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: 04/08/2023] [Revised: 06/08/2023] [Accepted: 06/21/2023] [Indexed: 07/03/2023]
Abstract
DNA repair pathways are tightly regulated processes that recognize specific hallmarks of DNA damage and coordinate lesion repair through discrete mechanisms, all within the context of a three-dimensional chromatin landscape. Dysregulation or malfunction of any one of the protein constituents in these pathways can contribute to aging and a variety of diseases. While the collective action of these many proteins is what drives DNA repair on the organismal scale, it is the interactions between individual proteins and DNA that facilitate each step of these pathways. In much the same way that ensemble biochemical techniques have characterized the various steps of DNA repair pathways, single-molecule imaging (SMI) approaches zoom in further, characterizing the individual protein-DNA interactions that compose each pathway step. SMI techniques offer the high resolving power needed to characterize the molecular structure and functional dynamics of individual biological interactions on the nanoscale. In this review, we highlight how our lab has used SMI techniques - traditional atomic force microscopy (AFM) imaging in air, high-speed AFM (HS-AFM) in liquids, and the DNA tightrope assay - over the past decade to study protein-nucleic acid interactions involved in DNA repair, mitochondrial DNA replication, and telomere maintenance. We discuss how DNA substrates containing specific DNA sequences or structures that emulate DNA repair intermediates or telomeres were generated and validated. For each highlighted project, we discuss novel findings made possible by the spatial and temporal resolution offered by these SMI techniques and unique DNA substrates.
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Affiliation(s)
| | - Hong Wang
- Toxicology Program, North Carolina State University, Raleigh, NC, USA; Physics Department, North Carolina State University, Raleigh, NC, USA; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA.
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18
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Pobegalov G, Chu LY, Peters JM, Molodtsov MI. Single cohesin molecules generate force by two distinct mechanisms. Nat Commun 2023; 14:3946. [PMID: 37402740 DOI: 10.1038/s41467-023-39696-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/23/2023] [Indexed: 07/06/2023] Open
Abstract
Spatial organization of DNA is facilitated by cohesin protein complexes that move on DNA and extrude DNA loops. How cohesin works mechanistically as a molecular machine is poorly understood. Here, we measure mechanical forces generated by conformational changes in single cohesin molecules. We show that bending of SMC coiled coils is driven by random thermal fluctuations leading to a ~32 nm head-hinge displacement that resists forces up to 1 pN; ATPase head engagement occurs in a single step of ~10 nm and is driven by an ATP dependent head-head movement, resisting forces up to 15 pN. Our molecular dynamic simulations show that the energy of head engagement can be stored in a mechanically strained conformation of NIPBL and released during disengagement. These findings reveal how single cohesin molecules generate force by two distinct mechanisms. We present a model, which proposes how this ability may power different aspects of cohesin-DNA interaction.
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Affiliation(s)
- Georgii Pobegalov
- The Francis Crick Institute, London, NW1 1AT, UK
- Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK
| | - Lee-Ya Chu
- The Francis Crick Institute, London, NW1 1AT, UK
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter, Vienna, 1030, Austria
| | - Maxim I Molodtsov
- The Francis Crick Institute, London, NW1 1AT, UK.
- Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK.
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter, Vienna, 1030, Austria.
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19
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Bailey MLP, Surovtsev I, Williams JF, Yan H, Yuan T, Li K, Duseau K, Mochrie SGJ, King MC. Loops and the activity of loop extrusion factors constrain chromatin dynamics. Mol Biol Cell 2023; 34:ar78. [PMID: 37126401 PMCID: PMC10398873 DOI: 10.1091/mbc.e23-04-0119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/02/2023] Open
Abstract
The chromosomes-DNA polymers and their binding proteins-are compacted into a spatially organized, yet dynamic, three-dimensional structure. Recent genome-wide chromatin conformation capture experiments reveal a hierarchical organization of the DNA structure that is imposed, at least in part, by looping interactions arising from the activity of loop extrusion factors. The dynamics of chromatin reflects the response of the polymer to a combination of thermal fluctuations and active processes. However, how chromosome structure and enzymes acting on chromatin together define its dynamics remains poorly understood. To gain insight into the structure-dynamics relationship of chromatin, we combine high-precision microscopy in living Schizosaccharomyces pombe cells with systematic genetic perturbations and Rouse model polymer simulations. We first investigated how the activity of two loop extrusion factors, the cohesin and condensin complexes, influences chromatin dynamics. We observed that deactivating cohesin, or to a lesser extent condensin, increased chromatin mobility, suggesting that loop extrusion constrains rather than agitates chromatin motion. Our corresponding simulations reveal that the introduction of loops is sufficient to explain the constraining activity of loop extrusion factors, highlighting that the conformation adopted by the polymer plays a key role in defining its dynamics. Moreover, we find that the number of loops or residence times of loop extrusion factors influence the dynamic behavior of the chromatin polymer. Last, we observe that the activity of the INO80 chromatin remodeler, but not the SWI/SNF or RSC complexes, is critical for ATP-dependent chromatin mobility in fission yeast. Taking the data together, we suggest that thermal and INO80-dependent activities exert forces that drive chromatin fluctuations, which are constrained by the organization of the chromosome into loops.
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Affiliation(s)
- Mary Lou P. Bailey
- Department of Applied Physics, Yale University, New Haven, CT 06511
- Integrated Graduate Program in Physics Engineering Biology, Yale University, New Haven, CT 06511
| | - Ivan Surovtsev
- Department of Physics, Yale University, New Haven, CT 06511
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | | | - Hao Yan
- Integrated Graduate Program in Physics Engineering Biology, Yale University, New Haven, CT 06511
- Department of Physics, Yale University, New Haven, CT 06511
| | - Tianyu Yuan
- Integrated Graduate Program in Physics Engineering Biology, Yale University, New Haven, CT 06511
- Department of Physics, Yale University, New Haven, CT 06511
| | - Kevin Li
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | - Katherine Duseau
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | - Simon G. J. Mochrie
- Department of Applied Physics, Yale University, New Haven, CT 06511
- Integrated Graduate Program in Physics Engineering Biology, Yale University, New Haven, CT 06511
- Department of Physics, Yale University, New Haven, CT 06511
| | - Megan C. King
- Integrated Graduate Program in Physics Engineering Biology, Yale University, New Haven, CT 06511
- Department of Molecular, Cell and Developmental Biology, Yale University, New Haven, CT 06511
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
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20
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Borrie MS, Kraycer PM, Gartenberg MR. Transcription-Driven Translocation of Cohesive and Non-Cohesive Cohesin In Vivo. Mol Cell Biol 2023; 43:254-268. [PMID: 37178128 PMCID: PMC10251789 DOI: 10.1080/10985549.2023.2199660] [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: 01/03/2023] [Revised: 03/23/2023] [Accepted: 03/28/2023] [Indexed: 05/15/2023] Open
Abstract
Cohesin is a central architectural element of chromosomes that regulates numerous DNA-based events. The complex holds sister chromatids together until anaphase onset and organizes individual chromosomal DNAs into loops and self-associating domains. Purified cohesin diffuses along DNA in an ATP-independent manner but can be propelled by transcribing RNA polymerase. In conjunction with a cofactor, the complex also extrudes DNA loops in an ATP-dependent manner. In this study we examine transcription-driven translocation of cohesin under various conditions in yeast. To this end, obstacles of increasing size were tethered to DNA to act as roadblocks to complexes mobilized by an inducible gene. The obstacles were built from a GFP-lacI core fused to one or more mCherries. A chimera with four mCherries blocked cohesin passage in late G1. During M phase, the threshold barrier depended on the state of cohesion: non-cohesive complexes were also blocked by four mCherries whereas cohesive complexes were blocked by as few as three mCherries. Furthermore cohesive complexes that were stalled at obstacles, in turn, blocked the passage of non-cohesive complexes. That synthetic barriers capture mobilized cohesin demonstrates that transcription-driven complexes translocate processively in vivo. Together, this study reveals unexplored limitations to cohesin movement on chromosomes.
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Affiliation(s)
- Melinda S. Borrie
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Paul M. Kraycer
- Graduate Program in Cellular and Molecular Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Marc R. Gartenberg
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
- Member of The Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
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21
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Zernia S, Stigler J. DNA curtains for studying phase separation mechanisms of DNA-organizing proteins. Methods Cell Biol 2023; 182:95-108. [PMID: 38359990 DOI: 10.1016/bs.mcb.2023.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Phase separation is one key mechanism to organize chromatin into compartments and to regulate the activity of the genome. The formation of liquid-like droplets within the nucleus is driven by protein association to the DNA via multivalent binding and the recruitment of other proteins building a concentrated reaction environment. Common methods to study phase separation and its liquid-like nature are based on microscopy of the formed droplets but lack the resolution to obtain information on the molecular level. Here, we describe the application of the DNA curtain technique for studying protein-mediated phase separation on DNA. For this, multiple lipid-anchored DNA strands are flow-stretched across a nanobarrier to allow single-molecule studies of protein-DNA interactions in a high-throughput approach. Our protocol describes how protein-induced DNA compaction can be observed in real-time and which wash protocols are suitable to characterize the interactions that promote condensate formation. Furthermore, we demonstrate how fluorescently labeled tracer proteins can serve as orientation points to examine the DNA compaction mechanism in detail.
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Affiliation(s)
- Sarah Zernia
- Gene Center Munich, Ludwig Maximilian University, Munich, Germany
| | - Johannes Stigler
- Gene Center Munich, Ludwig Maximilian University, Munich, Germany.
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22
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Banigan EJ, Tang W, van den Berg AA, Stocsits RR, Wutz G, Brandão HB, Busslinger GA, Peters JM, Mirny LA. Transcription shapes 3D chromatin organization by interacting with loop extrusion. Proc Natl Acad Sci U S A 2023; 120:e2210480120. [PMID: 36897969 PMCID: PMC10089175 DOI: 10.1073/pnas.2210480120] [Citation(s) in RCA: 103] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 12/03/2022] [Indexed: 03/12/2023] Open
Abstract
Cohesin folds mammalian interphase chromosomes by extruding the chromatin fiber into numerous loops. "Loop extrusion" can be impeded by chromatin-bound factors, such as CTCF, which generates characteristic and functional chromatin organization patterns. It has been proposed that transcription relocalizes or interferes with cohesin and that active promoters are cohesin loading sites. However, the effects of transcription on cohesin have not been reconciled with observations of active extrusion by cohesin. To determine how transcription modulates extrusion, we studied mouse cells in which we could alter cohesin abundance, dynamics, and localization by genetic "knockouts" of the cohesin regulators CTCF and Wapl. Through Hi-C experiments, we discovered intricate, cohesin-dependent contact patterns near active genes. Chromatin organization around active genes exhibited hallmarks of interactions between transcribing RNA polymerases (RNAPs) and extruding cohesins. These observations could be reproduced by polymer simulations in which RNAPs were moving barriers to extrusion that obstructed, slowed, and pushed cohesins. The simulations predicted that preferential loading of cohesin at promoters is inconsistent with our experimental data. Additional ChIP-seq experiments showed that the putative cohesin loader Nipbl is not predominantly enriched at promoters. Therefore, we propose that cohesin is not preferentially loaded at promoters and that the barrier function of RNAP accounts for cohesin accumulation at active promoters. Altogether, we find that RNAP is an extrusion barrier that is not stationary, but rather, translocates and relocalizes cohesin. Loop extrusion and transcription might interact to dynamically generate and maintain gene interactions with regulatory elements and shape functional genomic organization.
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Affiliation(s)
- Edward J. Banigan
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Wen Tang
- Research Institute of Molecular Pathology, Vienna BioCenter1030Vienna, Austria
| | - Aafke A. van den Berg
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Roman R. Stocsits
- Research Institute of Molecular Pathology, Vienna BioCenter1030Vienna, Austria
| | - Gordana Wutz
- Research Institute of Molecular Pathology, Vienna BioCenter1030Vienna, Austria
| | - Hugo B. Brandão
- Graduate Program in Biophysics, Harvard University, Cambridge, MA02138
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA02139
- The Broad Institute of MIT and Harvard, Cambridge, MA02142
| | - Georg A. Busslinger
- Research Institute of Molecular Pathology, Vienna BioCenter1030Vienna, Austria
- Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna1090, Austria
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna1090, Austria
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology, Vienna BioCenter1030Vienna, Austria
| | - Leonid A. Mirny
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA02139
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA02139
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23
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Minamino M, Bouchoux C, Canal B, Diffley JFX, Uhlmann F. A replication fork determinant for the establishment of sister chromatid cohesion. Cell 2023; 186:837-849.e11. [PMID: 36693376 DOI: 10.1016/j.cell.2022.12.044] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 11/08/2022] [Accepted: 12/22/2022] [Indexed: 01/24/2023]
Abstract
Concomitant with DNA replication, the chromosomal cohesin complex establishes cohesion between newly replicated sister chromatids. Cohesion establishment requires acetylation of conserved cohesin lysine residues by Eco1 acetyltransferase. Here, we explore how cohesin acetylation is linked to DNA replication. Biochemical reconstitution of replication-coupled cohesin acetylation reveals that transient DNA structures, which form during DNA replication, control the acetylation reaction. As polymerases complete lagging strand replication, strand displacement synthesis produces DNA flaps that are trimmed to result in nicked double-stranded DNA. Both flaps and nicks stimulate cohesin acetylation, while subsequent nick ligation to complete Okazaki fragment maturation terminates the acetylation reaction. A flapped or nicked DNA substrate constitutes a transient molecular clue that directs cohesin acetylation to a window behind the replication fork, next to where cohesin likely entraps both sister chromatids. Our results provide an explanation for how DNA replication is linked to sister chromatid cohesion establishment.
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Affiliation(s)
- Masashi Minamino
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Céline Bouchoux
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Berta Canal
- Chromosome Replication Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - John F X Diffley
- Chromosome Replication Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
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24
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Choudhary K, Kupiec M. The cohesin complex of yeasts: sister chromatid cohesion and beyond. FEMS Microbiol Rev 2023; 47:6825453. [PMID: 36370456 DOI: 10.1093/femsre/fuac045] [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: 09/13/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022] Open
Abstract
Each time a cell divides, it needs to duplicate the genome and then separate the two copies. In eukaryotes, which usually have more than one linear chromosome, this entails tethering the two newly replicated DNA molecules, a phenomenon known as sister chromatid cohesion (SCC). Cohesion ensures proper chromosome segregation to separate poles during mitosis. SCC is achieved by the presence of the cohesin complex. Besides its canonical function, cohesin is essential for chromosome organization and DNA damage repair. Surprisingly, yeast cohesin is loaded in G1 before DNA replication starts but only acquires its binding activity during DNA replication. Work in microorganisms, such as Saccharomyces cerevisiae and Schizosaccharomyces pombe has greatly contributed to the understanding of cohesin composition and functions. In the last few years, much progress has been made in elucidating the role of cohesin in chromosome organization and compaction. Here, we discuss the different functions of cohesin to ensure faithful chromosome segregation and genome stability during the mitotic cell division in yeast. We describe what is known about its composition and how DNA replication is coupled with SCC establishment. We also discuss current models for the role of cohesin in chromatin loop extrusion and delineate unanswered questions about the activity of this important, conserved complex.
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Affiliation(s)
- Karan Choudhary
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Martin Kupiec
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
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25
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Freitag M, Jaklin S, Padovani F, Radzichevici E, Zernia S, Schmoller KM, Stigler J. Single-molecule experiments reveal the elbow as an essential folding guide in SMC coiled-coil arms. Biophys J 2022; 121:4702-4713. [PMID: 36242515 PMCID: PMC9748247 DOI: 10.1016/j.bpj.2022.10.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 09/16/2022] [Accepted: 10/12/2022] [Indexed: 11/19/2022] Open
Abstract
Structural maintenance of chromosome (SMC) complexes form ring-like structures through exceptional elongated coiled-coils (CCs). Recent studies found that variable CC conformations, including open and collapsed forms, which might result from discontinuities in the CC, facilitate the diverse functions of SMCs in DNA organization. However, a detailed description of the SMC CC architecture is still missing. Here, we study the structural composition and mechanical properties of SMC proteins with optical tweezers unfolding experiments using the isolated Psm3 CC as a model system. We find a comparatively unstable protein with three unzipping intermediates, which we could directly assign to CC features by crosslinking experiments and state-of-the-art prediction software. Particularly, the CC elbow is shown to be a flexible, potentially non-structured feature, which divides the CC into sections, induces a pairing shift from one CC strand to the other and could facilitate large-scale conformational changes, most likely via thermal fluctuations of the flanking CC sections. A replacement of the elbow amino acids hinders folding of the consecutive CC region and frequently leads to non-native misalignments, revealing the elbow as a guide for proper folding. Additional in vivo manipulation of the elbow flexibility resulted in impaired cohesin complexes, which directly link the sensitive CC architecture to the biological function of cohesin.
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Affiliation(s)
- Marvin Freitag
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Sigrun Jaklin
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Francesco Padovani
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany
| | | | - Sarah Zernia
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Kurt M Schmoller
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Johannes Stigler
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany.
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26
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Stabilization of DNA fork junctions by Smc5/6 complexes revealed by single-molecule imaging. Cell Rep 2022; 41:111778. [PMID: 36476856 PMCID: PMC9756111 DOI: 10.1016/j.celrep.2022.111778] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 09/15/2022] [Accepted: 11/11/2022] [Indexed: 12/12/2022] Open
Abstract
SMC complexes play key roles in genome maintenance, where they ensure efficient genome replication and segregation. The SMC complex Smc5/6 is a crucial player in DNA replication and repair, yet many molecular features that determine its roles are unclear. Here, we use single-molecule microscopy to investigate Smc5/6's interaction with DNA. We find that Smc5/6 forms oligomers that dynamically redistribute on dsDNA by 1D diffusion and statically bind to ssDNA. Using combined force manipulation and single-molecule microscopy, we generate ssDNA-dsDNA junctions that mimic structures present in DNA repair intermediates or replication forks. We show that Smc5/6 accumulates at these junction sites, stabilizes the fork, and promotes the retention of RPA. Our observations provide a model for the complex's enrichment at sites of replication stress and DNA lesions from where it coordinates the recruitment and activation of downstream repair proteins.
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27
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Kim J, Jimenez DS, Ragipani B, Zhang B, Street LA, Kramer M, Albritton SE, Winterkorn LH, Morao AK, Ercan S. Condensin DC loads and spreads from recruitment sites to create loop-anchored TADs in C. elegans. eLife 2022; 11:e68745. [PMID: 36331876 PMCID: PMC9635877 DOI: 10.7554/elife.68745] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 10/23/2022] [Indexed: 11/06/2022] Open
Abstract
Condensins are molecular motors that compact DNA via linear translocation. In Caenorhabditis elegans, the X-chromosome harbors a specialized condensin that participates in dosage compensation (DC). Condensin DC is recruited to and spreads from a small number of recruitment elements on the X-chromosome (rex) and is required for the formation of topologically associating domains (TADs). We take advantage of autosomes that are largely devoid of condensin DC and TADs to address how rex sites and condensin DC give rise to the formation of TADs. When an autosome and X-chromosome are physically fused, despite the spreading of condensin DC into the autosome, no TAD was created. Insertion of a strong rex on the X-chromosome results in the TAD boundary formation regardless of sequence orientation. When the same rex is inserted on an autosome, despite condensin DC recruitment, there was no spreading or features of a TAD. On the other hand, when a 'super rex' composed of six rex sites or three separate rex sites are inserted on an autosome, recruitment and spreading of condensin DC led to the formation of TADs. Therefore, recruitment to and spreading from rex sites are necessary and sufficient for recapitulating loop-anchored TADs observed on the X-chromosome. Together our data suggest a model in which rex sites are both loading sites and bidirectional barriers for condensin DC, a one-sided loop-extruder with movable inactive anchor.
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Affiliation(s)
- Jun Kim
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - David S Jimenez
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Bhavana Ragipani
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Bo Zhang
- UCSF HSWSan FranciscoUnited States
| | - Lena A Street
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Maxwell Kramer
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Sarah E Albritton
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Lara H Winterkorn
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Ana K Morao
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
| | - Sevinc Ercan
- Department of Biology and Center for Genomics and Systems Biology, New York UniversityNew YorkUnited States
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28
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Reed KSM, Davis ES, Bond ML, Cabrera A, Thulson E, Quiroga IY, Cassel S, Woolery KT, Hilton I, Won H, Love MI, Phanstiel DH. Temporal analysis suggests a reciprocal relationship between 3D chromatin structure and transcription. Cell Rep 2022; 41:111567. [PMID: 36323252 PMCID: PMC9707392 DOI: 10.1016/j.celrep.2022.111567] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/19/2022] [Accepted: 10/05/2022] [Indexed: 11/06/2022] Open
Abstract
To infer potential causal relationships between 3D chromatin structure, enhancers, and gene transcription, we mapped each feature in a genome-wide fashion across eight narrowly spaced time points of macrophage activation. Enhancers and genes connected by loops exhibit stronger correlations between histone H3K27 acetylation and expression than can be explained by genomic distance or physical proximity alone. At these looped enhancer-promoter pairs, changes in acetylation at distal enhancers precede changes in gene expression. Changes in gene expression exhibit a directional bias at differential loop anchors; gained loops are associated with increased expression of genes oriented away from the center of the loop, and lost loops are often accompanied by high levels of transcription within the loop boundaries themselves. These results are consistent with a reciprocal relationship where loops can facilitate increased transcription by connecting promoters to distal enhancers, whereas high levels of transcription can impede loop formation.
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Affiliation(s)
- Kathleen S M Reed
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Eric S Davis
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Marielle L Bond
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Alan Cabrera
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
| | - Eliza Thulson
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Ivana Yoseli Quiroga
- Thurston Arthritis Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Shannon Cassel
- Thurston Arthritis Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Kamisha T Woolery
- Thurston Arthritis Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Isaac Hilton
- Department of Bioengineering, Rice University, Houston, TX 77005, USA; Department of Biosciences, Rice University, Houston, TX 77005, USA
| | - Hyejung Won
- Department of Genetics and Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA; Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Michael I Love
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biostatistics, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA
| | - Douglas H Phanstiel
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Bioinformatics and Computational Biology, University of North Carolina, Chapel Hill, NC 27599, USA; Thurston Arthritis Research Center, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA.
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29
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Pradhan B, Barth R, Kim E, Davidson IF, Bauer B, van Laar T, Yang W, Ryu JK, van der Torre J, Peters JM, Dekker C. SMC complexes can traverse physical roadblocks bigger than their ring size. Cell Rep 2022; 41:111491. [PMID: 36261017 DOI: 10.1101/2021.07.15.452501] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 05/19/2022] [Accepted: 09/21/2022] [Indexed: 05/17/2023] Open
Abstract
Ring-shaped structural maintenance of chromosomes (SMC) complexes like condensin and cohesin extrude loops of DNA. It remains, however, unclear how they can extrude DNA loops in chromatin that is bound with proteins. Here, we use in vitro single-molecule visualization to show that nucleosomes, RNA polymerase, and dCas9 pose virtually no barrier to loop extrusion by yeast condensin. We find that even DNA-bound nanoparticles as large as 200 nm, much bigger than the SMC ring size, also translocate into DNA loops during extrusion by condensin and cohesin. This even occurs for a single-chain version of cohesin in which the ring-forming subunits are covalently linked and cannot open to entrap DNA. The data show that SMC-driven loop extrusion has surprisingly little difficulty in accommodating large roadblocks into the loop. The findings also show that the extruded DNA does not pass through the SMC ring (pseudo)topologically, hence pointing to a nontopological mechanism for DNA loop extrusion.
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Affiliation(s)
- Biswajit Pradhan
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Roman Barth
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Eugene Kim
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Iain F Davidson
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Benedikt Bauer
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Theo van Laar
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands; Nynke Dekker Lab, Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Wayne Yang
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Je-Kyung Ryu
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Jaco van der Torre
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands.
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30
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SMC complexes can traverse physical roadblocks bigger than their ring size. Cell Rep 2022; 41:111491. [DOI: 10.1016/j.celrep.2022.111491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 05/19/2022] [Accepted: 09/21/2022] [Indexed: 11/24/2022] Open
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31
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Zhou M. DNA sliding and loop formation by E. coli SMC complex: MukBEF. Biochem Biophys Rep 2022; 31:101297. [PMID: 35770038 PMCID: PMC9234588 DOI: 10.1016/j.bbrep.2022.101297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 05/08/2022] [Accepted: 06/06/2022] [Indexed: 11/29/2022] Open
Abstract
SMC (structural maintenance of chromosomes) complexes share conserved architectures and function in chromosome maintenance via an unknown mechanism. Here we have used single-molecule techniques to study MukBEF, the SMC complex in Escherichia coli. Real-time movies show MukB alone can compact DNA and ATP inhibits DNA compaction by MukB. We observed that DNA unidirectionally slides through MukB, potentially by a ratchet mechanism, and the sliding speed depends on the elastic energy stored in the DNA. MukE, MukF and ATP binding stabilize MukB and DNA interaction, and ATP hydrolysis regulates the loading/unloading of MukBEF from DNA. Our data suggests a new model for how MukBEF organizes the bacterial chromosome in vivo; and this model will be relevant for other SMC proteins.
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Affiliation(s)
- Man Zhou
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
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32
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Warrier T, El Farran C, Zeng Y, Ho B, Bao Q, Zheng Z, Bi X, Ng HH, Ong D, Chu J, Sanyal A, Fullwood MJ, Collins J, Li H, Xu J, Loh YH. SETDB1 acts as a topological accessory to Cohesin via an H3K9me3-independent, genomic shunt for regulating cell fates. Nucleic Acids Res 2022; 50:7326-7349. [PMID: 35776115 PMCID: PMC9303280 DOI: 10.1093/nar/gkac531] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 05/30/2022] [Accepted: 06/30/2022] [Indexed: 11/13/2022] Open
Abstract
SETDB1 is a key regulator of lineage-specific genes and endogenous retroviral elements (ERVs) through its deposition of repressive H3K9me3 mark. Apart from its H3K9me3 regulatory role, SETDB1 has seldom been studied in terms of its other potential regulatory roles. To investigate this, a genomic survey of SETDB1 binding in mouse embryonic stem cells across multiple libraries was conducted, leading to the unexpected discovery of regions bereft of common repressive histone marks (H3K9me3, H3K27me3). These regions were enriched with the CTCF motif that is often associated with the topological regulator Cohesin. Further profiling of these non-H3K9me3 regions led to the discovery of a cluster of non-repeat loci that were co-bound by SETDB1 and Cohesin. These regions, which we named DiSCs (domains involving SETDB1 and Cohesin) were seen to be proximal to the gene promoters involved in embryonic stem cell pluripotency and lineage development. Importantly, it was found that SETDB1-Cohesin co-regulate target gene expression and genome topology at these DiSCs. Depletion of SETDB1 led to localized dysregulation of Cohesin binding thereby locally disrupting topological structures. Dysregulated gene expression trends revealed the importance of this cluster in ES cell maintenance as well as at gene 'islands' that drive differentiation to other lineages. The 'unearthing' of the DiSCs thus unravels a unique topological and transcriptional axis of control regulated chiefly by SETDB1.
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Affiliation(s)
- Tushar Warrier
- Cell Fate Engineering and Therapeutics Lab, Cell Biology and Therapies Division, A*STAR Institute of Molecular and Cell Biology, Singapore 138673, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Chadi El Farran
- Cell Fate Engineering and Therapeutics Lab, Cell Biology and Therapies Division, A*STAR Institute of Molecular and Cell Biology, Singapore 138673, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Yingying Zeng
- Cell Fate Engineering and Therapeutics Lab, Cell Biology and Therapies Division, A*STAR Institute of Molecular and Cell Biology, Singapore 138673, Singapore
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore
| | - Benedict Shao Quan Ho
- Cell Fate Engineering and Therapeutics Lab, Cell Biology and Therapies Division, A*STAR Institute of Molecular and Cell Biology, Singapore 138673, Singapore
| | - Qiuye Bao
- Cell Fate Engineering and Therapeutics Lab, Cell Biology and Therapies Division, A*STAR Institute of Molecular and Cell Biology, Singapore 138673, Singapore
| | - Zi Hao Zheng
- Cell Fate Engineering and Therapeutics Lab, Cell Biology and Therapies Division, A*STAR Institute of Molecular and Cell Biology, Singapore 138673, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - Xuezhi Bi
- Proteomics Group, Bioprocessing Technology Institute, A*STAR, Singapore 138668, Singapore
| | - Huck Hui Ng
- Gene Regulation Laboratory, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Derrick Sek Tong Ong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - Justin Jang Hann Chu
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- Infectious Disease Translational Research Programme, National University of Singapore, Singapore 117597, Singapore
| | - Amartya Sanyal
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore
| | - Melissa Jane Fullwood
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore
- Cancer Science Institute of Singapore, National University of Singapore, 14 Medical Drive, Singapore 117599, Singapore
| | - James J Collins
- Howard Hughes Medical Institute, Boston, MA 02114, USA
- Institute for Medical Engineering and Science Department of Biological Engineering, and Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02114, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Hu Li
- Center for Individualized Medicine, Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA
| | - Jian Xu
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
- Department of Plant Systems Physiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Yuin-Han Loh
- Cell Fate Engineering and Therapeutics Lab, Cell Biology and Therapies Division, A*STAR Institute of Molecular and Cell Biology, Singapore 138673, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 28 MedicalDrive, Singapore 117456, Singapore
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33
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Dequeker BJH, Scherr MJ, Brandão HB, Gassler J, Powell S, Gaspar I, Flyamer IM, Lalic A, Tang W, Stocsits R, Davidson IF, Peters JM, Duderstadt KE, Mirny LA, Tachibana K. MCM complexes are barriers that restrict cohesin-mediated loop extrusion. Nature 2022; 606:197-203. [PMID: 35585235 PMCID: PMC9159944 DOI: 10.1038/s41586-022-04730-0] [Citation(s) in RCA: 82] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 04/06/2022] [Indexed: 12/23/2022]
Abstract
Eukaryotic genomes are compacted into loops and topologically associating domains (TADs)1-3, which contribute to transcription, recombination and genomic stability4,5. Cohesin extrudes DNA into loops that are thought to lengthen until CTCF boundaries are encountered6-12. Little is known about whether loop extrusion is impeded by DNA-bound machines. Here we show that the minichromosome maintenance (MCM) complex is a barrier that restricts loop extrusion in G1 phase. Single-nucleus Hi-C (high-resolution chromosome conformation capture) of mouse zygotes reveals that MCM loading reduces CTCF-anchored loops and decreases TAD boundary insulation, which suggests that loop extrusion is impeded before reaching CTCF. This effect extends to HCT116 cells, in which MCMs affect the number of CTCF-anchored loops and gene expression. Simulations suggest that MCMs are abundant, randomly positioned and partially permeable barriers. Single-molecule imaging shows that MCMs are physical barriers that frequently constrain cohesin translocation in vitro. Notably, chimeric yeast MCMs that contain a cohesin-interaction motif from human MCM3 induce cohesin pausing, indicating that MCMs are 'active' barriers with binding sites. These findings raise the possibility that cohesin can arrive by loop extrusion at MCMs, which determine the genomic sites at which sister chromatid cohesion is established. On the basis of in vivo, in silico and in vitro data, we conclude that distinct loop extrusion barriers shape the three-dimensional genome.
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Affiliation(s)
- Bart J H Dequeker
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Matthias J Scherr
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry (MPIB), Martinsried, Germany
| | - Hugo B Brandão
- Harvard Program in Biophysics, Harvard University, Cambridge, MA, USA
- Illumina Inc., San Diego, CA, USA
| | - Johanna Gassler
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
- Department of Totipotency, Max Planck Institute of Biochemistry (MPIB), Martinsried, Germany
| | - Sean Powell
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Imre Gaspar
- Department of Totipotency, Max Planck Institute of Biochemistry (MPIB), Martinsried, Germany
| | - Ilya M Flyamer
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine (IGMM), University of Edinburgh, Edinburgh, UK
| | - Aleksandar Lalic
- Department of Totipotency, Max Planck Institute of Biochemistry (MPIB), Martinsried, Germany
| | - Wen Tang
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Roman Stocsits
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Iain F Davidson
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Karl E Duderstadt
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry (MPIB), Martinsried, Germany.
- Department of Physics, Technical University of Munich, Garching, Germany.
| | - Leonid A Mirny
- Department of Physics, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA.
| | - Kikuë Tachibana
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Vienna, Austria.
- Department of Totipotency, Max Planck Institute of Biochemistry (MPIB), Martinsried, Germany.
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34
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Nomidis SK, Carlon E, Gruber S, Marko JF. DNA tension-modulated translocation and loop extrusion by SMC complexes revealed by molecular dynamics simulations. Nucleic Acids Res 2022; 50:4974-4987. [PMID: 35474142 PMCID: PMC9122525 DOI: 10.1093/nar/gkac268] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 03/21/2022] [Accepted: 04/04/2022] [Indexed: 12/19/2022] Open
Abstract
Structural Maintenance of Chromosomes (SMC) complexes play essential roles in genome organization across all domains of life. To determine how the activities of these large (≈50 nm) complexes are controlled by ATP binding and hydrolysis, we developed a molecular dynamics model that accounts for conformational motions of the SMC and DNA. The model combines DNA loop capture with an ATP-induced 'power stroke' to translocate the SMC complex along DNA. This process is sensitive to DNA tension: at low tension (0.1 pN), the model makes loop-capture steps of average 60 nm and up to 200 nm along DNA (larger than the complex itself), while at higher tension, a distinct inchworm-like translocation mode appears. By tethering DNA to an experimentally-observed additional binding site ('safety belt'), the model SMC complex can perform loop extrusion (LE). The dependence of LE on DNA tension is distinct for fixed DNA tension vs. fixed DNA end points: LE reversal occurs above 0.5 pN for fixed tension, while LE stalling without reversal occurs at about 2 pN for fixed end points. Our model matches recent experimental results for condensin and cohesin, and makes testable predictions for how specific structural variations affect SMC function.
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Affiliation(s)
- Stefanos K Nomidis
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
- Flemish Institute for Technological Research (VITO), Boeretang 200, B-2400 Mol, Belgium
| | - Enrico Carlon
- Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Stephan Gruber
- Départment de Microbiologie Fondamentale, Université de Lausanne, 1015 Lausanne, Switzerland
| | - John F Marko
- Department of Physics and Astronomy, and Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA
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Xie L, Dong P, Qi Y, Hsieh THS, English BP, Jung S, Chen X, De Marzio M, Casellas R, Chang HY, Zhang B, Tjian R, Liu Z. BRD2 compartmentalizes the accessible genome. Nat Genet 2022; 54:481-491. [PMID: 35410381 PMCID: PMC9099420 DOI: 10.1038/s41588-022-01044-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 03/01/2022] [Indexed: 12/15/2022]
Abstract
Mammalian chromosomes are organized into megabase-sized compartments that are further subdivided into topologically associated domains (TADs). While the formation of TADs is dependent on Cohesin, the mechanism behind compartmentalization remains enigmatic. Here, we show that the bromodomain and extraterminal (BET) family scaffold protein BRD2 promotes spatial mixing and compartmentalization of active chromatin after Cohesin loss. This activity is independent of transcription but requires BRD2 to recognize acetylated targets through its double bromodomain and interact with binding partners with its low complexity domain. Notably, genome compartmentalization mediated by BRD2 is antagonized on one hand by Cohesin and on the other by the BET homolog protein BRD4, both of which inhibit BRD2 binding to chromatin. Polymer simulation of our data supports a BRD2-Cohesin interplay model of nuclear topology, where genome compartmentalization results from a competition between loop extrusion and chromatin state-specific affinity interactions.
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36
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Cummings CT, Rowley MJ. Implications of Dosage Deficiencies in CTCF and Cohesin on Genome Organization, Gene Expression, and Human Neurodevelopment. Genes (Basel) 2022; 13:583. [PMID: 35456389 PMCID: PMC9030571 DOI: 10.3390/genes13040583] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/14/2022] [Accepted: 03/24/2022] [Indexed: 02/07/2023] Open
Abstract
Properly organizing DNA within the nucleus is critical to ensure normal downstream nuclear functions. CTCF and cohesin act as major architectural proteins, working in concert to generate thousands of high-intensity chromatin loops. Due to their central role in loop formation, a massive research effort has been dedicated to investigating the mechanism by which CTCF and cohesin create these loops. Recent results lead to questioning the direct impact of CTCF loops on gene expression. Additionally, results of controlled depletion experiments in cell lines has indicated that genome architecture may be somewhat resistant to incomplete deficiencies in CTCF or cohesin. However, heterozygous human genetic deficiencies in CTCF and cohesin have illustrated the importance of their dosage in genome architecture, cellular processes, animal behavior, and disease phenotypes. Thus, the importance of considering CTCF or cohesin levels is especially made clear by these heterozygous germline variants that characterize genetic syndromes, which are increasingly recognized in clinical practice. Defined primarily by developmental delay and intellectual disability, the phenotypes of CTCF and cohesin deficiency illustrate the importance of architectural proteins particularly in neurodevelopment. We discuss the distinct roles of CTCF and cohesin in forming chromatin loops, highlight the major role that dosage of each protein plays in the amplitude of observed effects on gene expression, and contrast these results to heterozygous mutation phenotypes in murine models and clinical patients. Insights highlighted by this comparison have implications for future research into these newly emerging genetic syndromes.
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Affiliation(s)
- Christopher T. Cummings
- Munroe-Meyer Institute, Department of Genetic Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA;
- Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - M. Jordan Rowley
- Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
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37
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Scherr MJ, Wahab SA, Remus D, Duderstadt KE. Mobile origin-licensing factors confer resistance to conflicts with RNA polymerase. Cell Rep 2022; 38:110531. [PMID: 35320708 PMCID: PMC8961423 DOI: 10.1016/j.celrep.2022.110531] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 12/10/2021] [Accepted: 02/23/2022] [Indexed: 12/30/2022] Open
Abstract
Fundamental to our understanding of chromosome duplication is the idea that replication origins function both as sites where MCM helicases are loaded during the G1 phase and where synthesis begins in S phase. However, the temporal delay between phases exposes the replisome assembly pathway to potential disruption prior to replication. Using multicolor, single-molecule imaging, we systematically study the consequences of encounters between actively transcribing RNA polymerases (RNAPs) and replication initiation intermediates in the context of chromatin. We demonstrate that RNAP can push multiple licensed MCM helicases over long distances with nucleosomes ejected or displaced. Unexpectedly, we observe that MCM helicase loading intermediates also can be repositioned by RNAP and continue origin licensing after encounters with RNAP, providing a web of alternative origin specification pathways. Taken together, our observations reveal a surprising mobility in origin-licensing factors that confers resistance to the complex challenges posed by diverse obstacles encountered on chromosomes.
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Affiliation(s)
- Matthias J Scherr
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Syafiq Abd Wahab
- Memorial Sloan Kettering Cancer Center, Molecular Biology Program, 1275 York Avenue, New York, NY 10065, USA
| | - Dirk Remus
- Memorial Sloan Kettering Cancer Center, Molecular Biology Program, 1275 York Avenue, New York, NY 10065, USA
| | - Karl E Duderstadt
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany; Physik Department, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany.
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38
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Pommier Y, Nussenzweig A, Takeda S, Austin C. Human topoisomerases and their roles in genome stability and organization. Nat Rev Mol Cell Biol 2022; 23:407-427. [PMID: 35228717 PMCID: PMC8883456 DOI: 10.1038/s41580-022-00452-3] [Citation(s) in RCA: 230] [Impact Index Per Article: 76.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2022] [Indexed: 12/15/2022]
Abstract
Human topoisomerases comprise a family of six enzymes: two type IB (TOP1 and mitochondrial TOP1 (TOP1MT), two type IIA (TOP2A and TOP2B) and two type IA (TOP3A and TOP3B) topoisomerases. In this Review, we discuss their biochemistry and their roles in transcription, DNA replication and chromatin remodelling, and highlight the recent progress made in understanding TOP3A and TOP3B. Because of recent advances in elucidating the high-order organization of the genome through chromatin loops and topologically associating domains (TADs), we integrate the functions of topoisomerases with genome organization. We also discuss the physiological and pathological formation of irreversible topoisomerase cleavage complexes (TOPccs) as they generate topoisomerase DNA–protein crosslinks (TOP-DPCs) coupled with DNA breaks. We discuss the expanding number of redundant pathways that repair TOP-DPCs, and the defects in those pathways, which are increasingly recognized as source of genomic damage leading to neurological diseases and cancer. Topoisomerases have essential roles in transcription, DNA replication, chromatin remodelling and, as recently revealed, 3D genome organization. However, topoisomerases also generate DNA–protein crosslinks coupled with DNA breaks, which are increasingly recognized as a source of disease-causing genomic damage.
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Abstract
The centromere serves as the binding site for the kinetochore and is essential for the faithful segregation of chromosomes throughout cell division. The point centromere in yeast is encoded by a ∼115 bp specific DNA sequence, whereas regional centromeres range from 6-10 kbp in fission yeast to 5-10 Mbp in humans. Understanding the physical structure of centromere chromatin (pericentromere in yeast), defined as the chromatin between sister kinetochores, will provide fundamental insights into how centromere DNA is woven into a stiff spring that is able to resist microtubule pulling forces during mitosis. One hallmark of the pericentromere is the enrichment of the structural maintenance of chromosome (SMC) proteins cohesin and condensin. Based on studies from population approaches (ChIP-seq and Hi-C) and experimentally obtained images of fluorescent probes of pericentromeric structure, as well as quantitative comparisons between simulations and experimental results, we suggest a mechanism for building tension between sister kinetochores. We propose that the centromere is a chromatin bottlebrush that is organized by the loop-extruding proteins condensin and cohesin. The bottlebrush arrangement provides a biophysical means to transform pericentromeric chromatin into a spring due to the steric repulsion between radial loops. We argue that the bottlebrush is an organizing principle for chromosome organization that has emerged from multiple approaches in the field.
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40
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Bonato A, Michieletto D. Three-dimensional loop extrusion. Biophys J 2021; 120:5544-5552. [PMID: 34793758 PMCID: PMC8715238 DOI: 10.1016/j.bpj.2021.11.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 10/29/2021] [Accepted: 11/10/2021] [Indexed: 12/30/2022] Open
Abstract
Loop extrusion convincingly describes how certain structural maintenance of chromosome (SMC) proteins mediate the formation of large DNA loops. Yet most of the existing computational models cannot reconcile recent in vitro observations showing that condensins can traverse each other, bypass large roadblocks, and perform steps longer than their own size. To fill this gap, we propose a three-dimensional (3D) "trans-grabbing" model for loop extrusion, which not only reproduces the experimental features of loop extrusion by one SMC complex but also predicts the formation of so-called Z-loops via the interaction of two or more SMCs extruding along the same DNA substrate. By performing molecular dynamics simulations of this model, we discover that the experimentally observed asymmetry in the different types of Z-loops is a natural consequence of the DNA tethering in vitro. Intriguingly, our model predicts this bias to disappear in the absence of tethering and a third type of Z-loop, which has not yet been identified in experiments, to appear. Our model naturally explains roadblock bypassing and the appearance of steps larger than the SMC size as a consequence of non-contiguous DNA grabbing. Finally, this study is the first, to our knowledge, to address how Z-loops and bypassing might occur in a way that is broadly consistent with existing cis-only 1D loop extrusion models.
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Affiliation(s)
- Andrea Bonato
- University of Edinburgh, SUPA, School of Physics and Astronomy, Peter Guthrie Road, Edinburgh, UK
| | - Davide Michieletto
- University of Edinburgh, SUPA, School of Physics and Astronomy, Peter Guthrie Road, Edinburgh, UK; MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK.
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41
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van Schie JJM, de Lange J. The Interplay of Cohesin and the Replisome at Processive and Stressed DNA Replication Forks. Cells 2021; 10:3455. [PMID: 34943967 PMCID: PMC8700348 DOI: 10.3390/cells10123455] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/04/2021] [Accepted: 12/06/2021] [Indexed: 12/12/2022] Open
Abstract
The cohesin complex facilitates faithful chromosome segregation by pairing the sister chromatids after DNA replication until mitosis. In addition, cohesin contributes to proficient and error-free DNA replication. Replisome progression and establishment of sister chromatid cohesion are intimately intertwined processes. Here, we review how the key factors in DNA replication and cohesion establishment cooperate in unperturbed conditions and during DNA replication stress. We discuss the detailed molecular mechanisms of cohesin recruitment and the entrapment of replicated sister chromatids at the replisome, the subsequent stabilization of sister chromatid cohesion via SMC3 acetylation, as well as the role and regulation of cohesin in the response to DNA replication stress.
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Affiliation(s)
- Janne J. M. van Schie
- Cancer Center Amsterdam, Department of Human Genetics, Section Oncogenetics, Amsterdam University Medical Centers, De Boelelaan 1118, 1081 HV Amsterdam, The Netherlands
| | - Job de Lange
- Cancer Center Amsterdam, Department of Human Genetics, Section Oncogenetics, Amsterdam University Medical Centers, De Boelelaan 1118, 1081 HV Amsterdam, The Netherlands
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42
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Amândio AR, Beccari L, Lopez-Delisle L, Mascrez B, Zakany J, Gitto S, Duboule D. Sequential in cis mutagenesis in vivo reveals various functions for CTCF sites at the mouse HoxD cluster. Genes Dev 2021; 35:1490-1509. [PMID: 34711654 PMCID: PMC8559674 DOI: 10.1101/gad.348934.121] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 09/21/2021] [Indexed: 12/12/2022]
Abstract
Mammalian Hox gene clusters contain a range of CTCF binding sites. In addition to their importance in organizing a TAD border, which isolates the most posterior genes from the rest of the cluster, the positions and orientations of these sites suggest that CTCF may be instrumental in the selection of various subsets of contiguous genes, which are targets of distinct remote enhancers located in the flanking regulatory landscapes. We examined this possibility by producing an allelic series of cumulative in cis mutations in these sites, up to the abrogation of CTCF binding in the five sites located on one side of the TAD border. In the most impactful alleles, the global chromatin architecture of the locus was modified, yet not drastically, illustrating that CTCF sites located on one side of a strong TAD border are sufficient to organize at least part of this insulation. Spatial colinearity in the expression of these genes along the major body axis was nevertheless maintained, despite abnormal expression boundaries. In contrast, strong effects were scored in the selection of target genes responding to particular enhancers, leading to the misregulation of Hoxd genes in specific structures. Altogether, while most enhancer-promoter interactions can occur in the absence of this series of CTCF sites, the binding of CTCF in the Hox cluster is required to properly transform a rather unprecise process into a highly discriminative mechanism of interactions, which is translated into various patterns of transcription accompanied by the distinctive chromatin topology found at this locus. Our allelic series also allowed us to reveal the distinct functional contributions for CTCF sites within this Hox cluster, some acting as insulator elements, others being necessary to anchor or stabilize enhancer-promoter interactions, and some doing both, whereas they all together contribute to the formation of a TAD border. This variety of tasks may explain the amazing evolutionary conservation in the distribution of these sites among paralogous Hox clusters or between various vertebrates.
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Affiliation(s)
- Ana Rita Amândio
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Department of Genetics and Evolution, University of Geneva, 1211 Geneva, Switzerland
| | - Leonardo Beccari
- Department of Genetics and Evolution, University of Geneva, 1211 Geneva, Switzerland
| | - Lucille Lopez-Delisle
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Bénédicte Mascrez
- Department of Genetics and Evolution, University of Geneva, 1211 Geneva, Switzerland
| | - Jozsef Zakany
- Department of Genetics and Evolution, University of Geneva, 1211 Geneva, Switzerland
| | - Sandra Gitto
- Department of Genetics and Evolution, University of Geneva, 1211 Geneva, Switzerland
| | - Denis Duboule
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Department of Genetics and Evolution, University of Geneva, 1211 Geneva, Switzerland
- Collège de France, 75231 Paris, France
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43
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Goel VY, Hansen AS. The macro and micro of chromosome conformation capture. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2021; 10:e395. [PMID: 32987449 PMCID: PMC8236208 DOI: 10.1002/wdev.395] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/21/2020] [Accepted: 07/31/2020] [Indexed: 12/14/2022]
Abstract
The 3D organization of the genome facilitates gene regulation, replication, and repair, making it a key feature of genomic function and one that remains to be properly understood. Over the past two decades, a variety of chromosome conformation capture (3C) methods have delineated genome folding from megabase-scale compartments and topologically associating domains (TADs) down to kilobase-scale enhancer-promoter interactions. Understanding the functional role of each layer of genome organization is a gateway to understanding cell state, development, and disease. Here, we discuss the evolution of 3C-based technologies for mapping 3D genome organization. We focus on genomics methods and provide a historical account of the development from 3C to Hi-C. We also discuss ChIP-based techniques that focus on 3D genome organization mediated by specific proteins, capture-based methods that focus on particular regions or regulatory elements, 3C-orthogonal methods that do not rely on restriction digestion and proximity ligation, and methods for mapping the DNA-RNA and RNA-RNA interactomes. We consider the biological discoveries that have come from these methods, examine the mechanistic contributions of CTCF, cohesin, and loop extrusion to genomic folding, and detail the 3D genome field's current understanding of nuclear architecture. Finally, we give special consideration to Micro-C as an emerging frontier in chromosome conformation capture and discuss recent Micro-C findings uncovering fine-scale chromatin organization in unprecedented detail. This article is categorized under: Gene Expression and Transcriptional Hierarchies > Regulatory Mechanisms Gene Expression and Transcriptional Hierarchies > Gene Networks and Genomics.
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Affiliation(s)
- Viraat Y. Goel
- Department of Biological EngineeringMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Anders S. Hansen
- Department of Biological EngineeringMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
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44
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Yan H, Surovtsev I, Williams JF, Bailey MLP, King MC, Mochrie SGJ. Extrusion of chromatin loops by a composite loop extrusion factor. Phys Rev E 2021; 104:024414. [PMID: 34525654 DOI: 10.1103/physreve.104.024414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 06/16/2021] [Indexed: 12/26/2022]
Abstract
Chromatin loop extrusion by structural maintenance of chromosome (SMC) complexes is thought to underlie intermediate-scale chromatin organization inside cells. Motivated by a number of experiments suggesting that nucleosomes may block loop extrusion by SMCs, such as cohesin and condensin complexes, we introduce and characterize theoretically a composite loop extrusion factor (composite LEF) model. In addition to an SMC complex that creates a chromatin loop by encircling two threads of DNA, this model includes a remodeling complex that relocates or removes nucleosomes as it progresses along the chromatin, and nucleosomes that block SMC translocation along the DNA. Loop extrusion is enabled by SMC motion along nucleosome-free DNA, created in the wake of the remodeling complex, while nucleosome rebinding behind the SMC acts as a ratchet, holding the SMC close to the remodeling complex. We show that, for a wide range of parameter values, this collection of factors constitutes a composite LEF that extrudes loops with a velocity, comparable to the velocity of remodeling complex translocation on chromatin in the absence of SMC, and much faster than loop extrusion by an isolated SMC that is blocked by nucleosomes.
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Affiliation(s)
- Hao Yan
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, Connecticut 06511, USA.,Department of Physics, Yale University, New Haven, Connecticut 06511, USA
| | - Ivan Surovtsev
- Department of Physics, Yale University, New Haven, Connecticut 06511, USA.,Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Jessica F Williams
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Mary Lou P Bailey
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, Connecticut 06511, USA.,Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA
| | - Megan C King
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, Connecticut 06511, USA.,Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520, USA.,Department of Molecular, Cellular, 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 06511, USA.,Department of Physics, Yale University, New Haven, Connecticut 06511, USA.,Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA
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45
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Choppakatla P, Dekker B, Cutts EE, Vannini A, Dekker J, Funabiki H. Linker histone H1.8 inhibits chromatin binding of condensins and DNA topoisomerase II to tune chromosome length and individualization. eLife 2021; 10:e68918. [PMID: 34406118 PMCID: PMC8416026 DOI: 10.7554/elife.68918] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 08/13/2021] [Indexed: 12/14/2022] Open
Abstract
DNA loop extrusion by condensins and decatenation by DNA topoisomerase II (topo II) are thought to drive mitotic chromosome compaction and individualization. Here, we reveal that the linker histone H1.8 antagonizes condensins and topo II to shape mitotic chromosome organization. In vitro chromatin reconstitution experiments demonstrate that H1.8 inhibits binding of condensins and topo II to nucleosome arrays. Accordingly, H1.8 depletion in Xenopus egg extracts increased condensins and topo II levels on mitotic chromatin. Chromosome morphology and Hi-C analyses suggest that H1.8 depletion makes chromosomes thinner and longer through shortening the average loop size and reducing the DNA amount in each layer of mitotic loops. Furthermore, excess loading of condensins and topo II to chromosomes by H1.8 depletion causes hyper-chromosome individualization and dispersion. We propose that condensins and topo II are essential for chromosome individualization, but their functions are tuned by the linker histone to keep chromosomes together until anaphase.
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Affiliation(s)
- Pavan Choppakatla
- Laboratory of Chromosome and Cell Biology, The Rockefeller UniversityNew YorkUnited States
| | - Bastiaan Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical SchoolWorcesterUnited States
| | - Erin E Cutts
- Division of Structural Biology, The Institute of Cancer ResearchLondonUnited Kingdom
| | - Alessandro Vannini
- Division of Structural Biology, The Institute of Cancer ResearchLondonUnited Kingdom
- Fondazione Human Technopole, Structural Biology Research Centre, 20157MilanItaly
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical SchoolWorcesterUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Hironori Funabiki
- Laboratory of Chromosome and Cell Biology, The Rockefeller UniversityNew YorkUnited States
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46
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Neguembor MV, Martin L, Castells-García Á, Gómez-García PA, Vicario C, Carnevali D, AlHaj Abed J, Granados A, Sebastian-Perez R, Sottile F, Solon J, Wu CT, Lakadamyali M, Cosma MP. Transcription-mediated supercoiling regulates genome folding and loop formation. Mol Cell 2021; 81:3065-3081.e12. [PMID: 34297911 PMCID: PMC9482096 DOI: 10.1016/j.molcel.2021.06.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 03/27/2021] [Accepted: 06/08/2021] [Indexed: 12/21/2022]
Abstract
The chromatin fiber folds into loops, but the mechanisms controlling loop extrusion are still poorly understood. Using super-resolution microscopy, we visualize that loops in intact nuclei are formed by a scaffold of cohesin complexes from which the DNA protrudes. RNA polymerase II decorates the top of the loops and is physically segregated from cohesin. Augmented looping upon increased loading of cohesin on chromosomes causes disruption of Lamin at the nuclear rim and chromatin blending, a homogeneous distribution of chromatin within the nucleus. Altering supercoiling via either transcription or topoisomerase inhibition counteracts chromatin blending, increases chromatin condensation, disrupts loop formation, and leads to altered cohesin distribution and mobility on chromatin. Overall, negative supercoiling generated by transcription is an important regulator of loop formation in vivo.
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Affiliation(s)
- Maria Victoria Neguembor
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Laura Martin
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Álvaro Castells-García
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain; Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China
| | - Pablo Aurelio Gómez-García
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Chiara Vicario
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Davide Carnevali
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | | | - Alba Granados
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Ruben Sebastian-Perez
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Francesco Sottile
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Jérôme Solon
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Dr Aiguader 88, 08003 Barcelona, Spain; Instituto Biofisika (CSIC, UPV/EHU), Basque Excellence Research Centre, Barrio Sarriena, 48940, Leioa, Spain; Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Chao-Ting Wu
- Department of Genetics, Harvard Medical School, Boston, MA, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Melike Lakadamyali
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Maria Pia Cosma
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain; Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China; Universitat Pompeu Fabra (UPF), Dr Aiguader 88, 08003 Barcelona, Spain; ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain; CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
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47
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Golov AK, Golova AV, Gavrilov AA, Razin SV. Sensitivity of cohesin-chromatin association to high-salt treatment corroborates non-topological mode of loop extrusion. Epigenetics Chromatin 2021; 14:36. [PMID: 34321070 PMCID: PMC8320178 DOI: 10.1186/s13072-021-00411-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 07/19/2021] [Indexed: 12/18/2022] Open
Abstract
Cohesin is a key organizer of chromatin folding in eukaryotic cells. The two main activities of this ring-shaped protein complex are the maintenance of sister chromatid cohesion and the establishment of long-range DNA-DNA interactions through the process of loop extrusion. Although the basic principles of both cohesion and loop extrusion have been described, we still do not understand several crucial mechanistic details. One of such unresolved issues is the question of whether a cohesin ring topologically embraces DNA string(s) during loop extrusion. Here, we show that cohesin complexes residing on CTCF-occupied genomic sites in mammalian cells do not interact with DNA topologically. We assessed the stability of cohesin-dependent loops and cohesin association with chromatin in high-ionic-strength conditions in G1-synchronized HeLa cells. We found that increased salt concentration completely displaces cohesin from those genomic regions that correspond to CTCF-defined loop anchors. Unsurprisingly, CTCF-anchored cohesin loops also dissipate in these conditions. Because topologically engaged cohesin is considered to be salt resistant, our data corroborate a non-topological model of loop extrusion. We also propose a model of cohesin activity throughout the interphase, which essentially equates the termination of non-topological loop extrusion with topological loading of cohesin. This theoretical framework enables a parsimonious explanation of various seemingly contradictory experimental findings.
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Affiliation(s)
- Arkadiy K. Golov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- Mental Health Research Center, Moscow, Russia
| | - Anastasia V. Golova
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Alexey A. Gavrilov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Sergey V. Razin
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
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48
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Garcia P, Fernandez-Hernandez R, Cuadrado A, Coca I, Gomez A, Maqueda M, Latorre-Pellicer A, Puisac B, Ramos FJ, Sandoval J, Esteller M, Mosquera JL, Rodriguez J, Pié J, Losada A, Queralt E. Disruption of NIPBL/Scc2 in Cornelia de Lange Syndrome provokes cohesin genome-wide redistribution with an impact in the transcriptome. Nat Commun 2021; 12:4551. [PMID: 34315879 PMCID: PMC8316422 DOI: 10.1038/s41467-021-24808-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/05/2021] [Indexed: 12/31/2022] Open
Abstract
Cornelia de Lange syndrome (CdLS) is a rare disease affecting multiple organs and systems during development. Mutations in the cohesin loader, NIPBL/Scc2, were first described and are the most frequent in clinically diagnosed CdLS patients. The molecular mechanisms driving CdLS phenotypes are not understood. In addition to its canonical role in sister chromatid cohesion, cohesin is implicated in the spatial organization of the genome. Here, we investigate the transcriptome of CdLS patient-derived primary fibroblasts and observe the downregulation of genes involved in development and system skeletal organization, providing a link to the developmental alterations and limb abnormalities characteristic of CdLS patients. Genome-wide distribution studies demonstrate a global reduction of NIPBL at the NIPBL-associated high GC content regions in CdLS-derived cells. In addition, cohesin accumulates at NIPBL-occupied sites at CpG islands potentially due to reduced cohesin translocation along chromosomes, and fewer cohesin peaks colocalize with CTCF.
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Affiliation(s)
- Patricia Garcia
- Cell Cycle Group, Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), Av. Gran Via de L'Hospitalet 199-203, Barcelona, Spain.
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca and Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain.
| | - Rita Fernandez-Hernandez
- Cell Cycle Group, Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), Av. Gran Via de L'Hospitalet 199-203, Barcelona, Spain
| | - Ana Cuadrado
- Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Ignacio Coca
- Research and Development Department, qGenomics Laboratory, Esplugues de Llobregat, Spain
| | - Antonio Gomez
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Catalonia, Spain
- Grup de Recerca de Reumatologia, Parc Científic de Barcelona, Barcelona, Spain
| | - Maria Maqueda
- Bioinformatics Unit, Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), Av. Gran Via de L'Hospitalet 199-203, Barcelona, Spain
| | - Ana Latorre-Pellicer
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology-Physiology and Paediatrics, School of Medicine, University of Zaragoza, CIBERER-GCV02 and IISAragon, Zaragoza, Spain
| | - Beatriz Puisac
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology-Physiology and Paediatrics, School of Medicine, University of Zaragoza, CIBERER-GCV02 and IISAragon, Zaragoza, Spain
| | - Feliciano J Ramos
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology-Physiology and Paediatrics, School of Medicine, University of Zaragoza, CIBERER-GCV02 and IISAragon, Zaragoza, Spain
| | - Juan Sandoval
- Biomarkers and Precision Medicine Unit (UByMP) and Epigenomics Core Facility, Health Research Institute La Fe (IISLaFe), Valencia, Spain
| | - Manel Esteller
- Josep Carreras Leukaemia Research Institute (IJC), Barcelona, Catalonia, Spain
- Centro de Investigación Biomédica en Red Cáncer (CIBERONC), Madrid, Spain
- Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Catalonia, Spain
- Physiological Sciences Department, School of Medicine and Health Sciences, University of Barcelona, Barcelona, Catalonia, Spain
| | - Jose Luis Mosquera
- Bioinformatics Unit, Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), Av. Gran Via de L'Hospitalet 199-203, Barcelona, Spain
| | - Jairo Rodriguez
- Research and Development Department, qGenomics Laboratory, Esplugues de Llobregat, Spain
| | - J Pié
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology-Physiology and Paediatrics, School of Medicine, University of Zaragoza, CIBERER-GCV02 and IISAragon, Zaragoza, Spain
| | - Ana Losada
- Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Ethel Queralt
- Cell Cycle Group, Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), Av. Gran Via de L'Hospitalet 199-203, Barcelona, Spain.
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain.
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49
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Higashi TL, Pobegalov G, Tang M, Molodtsov MI, Uhlmann F. A Brownian ratchet model for DNA loop extrusion by the cohesin complex. eLife 2021; 10:e67530. [PMID: 34309513 PMCID: PMC8313234 DOI: 10.7554/elife.67530] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 06/10/2021] [Indexed: 12/12/2022] Open
Abstract
The cohesin complex topologically encircles DNA to promote sister chromatid cohesion. Alternatively, cohesin extrudes DNA loops, thought to reflect chromatin domain formation. Here, we propose a structure-based model explaining both activities. ATP and DNA binding promote cohesin conformational changes that guide DNA through a kleisin N-gate into a DNA gripping state. Two HEAT-repeat DNA binding modules, associated with cohesin's heads and hinge, are now juxtaposed. Gripping state disassembly, following ATP hydrolysis, triggers unidirectional hinge module movement, which completes topological DNA entry by directing DNA through the ATPase head gate. If head gate passage fails, hinge module motion creates a Brownian ratchet that, instead, drives loop extrusion. Molecular-mechanical simulations of gripping state formation and resolution cycles recapitulate experimentally observed DNA loop extrusion characteristics. Our model extends to asymmetric and symmetric loop extrusion, as well as z-loop formation. Loop extrusion by biased Brownian motion has important implications for chromosomal cohesin function.
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Affiliation(s)
- Torahiko L Higashi
- Chromosome Segregation Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Georgii Pobegalov
- Mechanobiology and Biophysics Laboratory, The Francis Crick InstituteLondonUnited Kingdom
- Department of Physics and Astronomy, University College LondonLondonUnited Kingdom
| | - Minzhe Tang
- Chromosome Segregation Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Maxim I Molodtsov
- Mechanobiology and Biophysics Laboratory, The Francis Crick InstituteLondonUnited Kingdom
- Department of Physics and Astronomy, University College LondonLondonUnited Kingdom
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick InstituteLondonUnited Kingdom
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50
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Yamamoto T, Sakaue T, Schiessel H. Slow chromatin dynamics enhances promoter accessibility to transcriptional condensates. Nucleic Acids Res 2021; 49:5017-5027. [PMID: 33885786 PMCID: PMC8136786 DOI: 10.1093/nar/gkab275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/19/2021] [Accepted: 04/20/2021] [Indexed: 01/17/2023] Open
Abstract
Enhancers are DNA sequences at a long genomic distance from target genes. Recent experiments suggest that enhancers are anchored to the surfaces of condensates of transcription machinery and that the loop extrusion process enhances the transcription level of their target genes. Here, we theoretically study the polymer dynamics driven by the loop extrusion of the linker DNA between an enhancer and the promoter of its target gene to calculate the contact probability of the promoter to the transcription machinery in the condensate. Our theory predicts that when the loop extrusion process is active, the contact probability increases with increasing linker DNA length. This finding reflects the fact that the relaxation time, with which the promoter stays in proximity to the surface of the transcriptional condensate, increases as the length of the linker DNA increases. This contrasts the equilibrium case for which the contact probability between the promoter and the transcription machineries is smaller for longer linker DNA lengths.
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Affiliation(s)
- Tetsuya Yamamoto
- Institute for Chemical Reaction Design and Discovery, Hokkaido University, Kita 21, Nishi 10, Kita-ku, Sapporo 001-0021, Japan.,PRESTO, Japan Science and Technology Agency (JST), 4-1-8, Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Takahiro Sakaue
- Department of Physical Sciences, Aoyama Gakuin University, 5-10-1, Fuchinobe,Chuo-ku, Sagamihara, Kanagawa 252-5258, Japan
| | - Helmut Schiessel
- Cluster of Excellence Physics of Life, TU Dresden, Dresden 01062, Germany
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