1
|
Flynn SM, Dhir S, Herka K, Doyle C, Melidis L, Simeone A, Hui WWI, Araujo Tavares RDC, Schoenfelder S, Tannahill D, Balasubramanian S. Improved simultaneous mapping of epigenetic features and 3D chromatin structure via ViCAR. Genome Biol 2024; 25:237. [PMID: 39227991 PMCID: PMC11370281 DOI: 10.1186/s13059-024-03377-6] [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: 03/11/2024] [Accepted: 08/25/2024] [Indexed: 09/05/2024] Open
Abstract
Methods to measure chromatin contacts at genomic regions bound by histone modifications or proteins are important tools to investigate chromatin organization. However, such methods do not capture the possible involvement of other epigenomic features such as G-quadruplex DNA secondary structures (G4s). To bridge this gap, we introduce ViCAR (viewpoint HiCAR), for the direct antibody-based capture of chromatin interactions at folded G4s. Through ViCAR, we showcase the first G4-3D interaction landscape. Using histone marks, we also demonstrate how ViCAR improves on earlier approaches yielding increased signal-to-noise. ViCAR is a practical and powerful tool to explore epigenetic marks and 3D genome interactomes.
Collapse
Affiliation(s)
- Sean M Flynn
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Somdutta Dhir
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Krzysztof Herka
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Colm Doyle
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Larry Melidis
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Angela Simeone
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Winnie W I Hui
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | | | | | - David Tannahill
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
| | - Shankar Balasubramanian
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK.
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
- School of Clinical Medicine, University of Cambridge, Cambridge, CB2 0SP, UK.
| |
Collapse
|
2
|
Pletenev I, Bazarevich M, Zagirova D, Kononkova A, Cherkasov A, Efimova O, Tiukacheva E, Morozov K, Ulianov K, Komkov D, Tvorogova A, Golimbet V, Kondratyev N, Razin S, Khaitovich P, Ulianov S, Khrameeva E. Extensive long-range polycomb interactions and weak compartmentalization are hallmarks of human neuronal 3D genome. Nucleic Acids Res 2024; 52:6234-6252. [PMID: 38647066 PMCID: PMC11194087 DOI: 10.1093/nar/gkae271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 03/21/2024] [Accepted: 04/06/2024] [Indexed: 04/25/2024] Open
Abstract
Chromatin architecture regulates gene expression and shapes cellular identity, particularly in neuronal cells. Specifically, polycomb group (PcG) proteins enable establishment and maintenance of neuronal cell type by reorganizing chromatin into repressive domains that limit the expression of fate-determining genes and sustain distinct gene expression patterns in neurons. Here, we map the 3D genome architecture in neuronal and non-neuronal cells isolated from the Wernicke's area of four human brains and comprehensively analyze neuron-specific aspects of chromatin organization. We find that genome segregation into active and inactive compartments is greatly reduced in neurons compared to other brain cells. Furthermore, neuronal Hi-C maps reveal strong long-range interactions, forming a specific network of PcG-mediated contacts in neurons that is nearly absent in other brain cells. These interacting loci contain developmental transcription factors with repressed expression in neurons and other mature brain cells. But only in neurons, they are rich in bivalent promoters occupied by H3K4me3 histone modification together with H3K27me3, which points to a possible functional role of PcG contacts in neurons. Importantly, other layers of chromatin organization also exhibit a distinct structure in neurons, characterized by an increase in short-range interactions and a decrease in long-range ones.
Collapse
Affiliation(s)
- Ilya A Pletenev
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Maria Bazarevich
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Diana R Zagirova
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
- A.A. Kharkevich Institute for Information Transmission Problems, Moscow 127051, Russia
| | - Anna D Kononkova
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Alexander V Cherkasov
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Olga I Efimova
- Vladimir Zelman Center for Neurobiology and Brain Rehabilitation, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Eugenia A Tiukacheva
- Department of Biological and Medical Physics, Moscow Institute of Physics and Technology, Moscow 141700, Russia
- Department of Molecular Biology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
- CNRS UMR9018, Institut Gustave Roussy, Villejuif 94805, France
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow 119334, Russia
- Department of Cellular Genomics, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Kirill V Morozov
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Kirill A Ulianov
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Dmitriy Komkov
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Anna V Tvorogova
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Vera E Golimbet
- Laboratory of Clinical Genetics, Mental Health Research Center, Moscow 115522, Russia
| | - Nikolay V Kondratyev
- Laboratory of Clinical Genetics, Mental Health Research Center, Moscow 115522, Russia
| | - Sergey V Razin
- Department of Molecular Biology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
- Department of Cellular Genomics, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Philipp Khaitovich
- Vladimir Zelman Center for Neurobiology and Brain Rehabilitation, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Sergey V Ulianov
- Department of Molecular Biology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
- Department of Cellular Genomics, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Ekaterina E Khrameeva
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| |
Collapse
|
3
|
Dunn-Davies H, Dudnakova T, Nogara A, Rodor J, Thomas AC, Parish E, Gautier P, Meynert A, Ulitsky I, Madeddu P, Caporali A, Baker A, Tollervey D, Mitić T. Control of endothelial cell function and arteriogenesis by MEG3:EZH2 epigenetic regulation of integrin expression. MOLECULAR THERAPY. NUCLEIC ACIDS 2024; 35:102173. [PMID: 38617973 PMCID: PMC11015509 DOI: 10.1016/j.omtn.2024.102173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 03/14/2024] [Indexed: 04/16/2024]
Abstract
Epigenetic processes involving long non-coding RNAs regulate endothelial gene expression. However, the underlying regulatory mechanisms causing endothelial dysfunction remain to be elucidated. Enhancer of zeste homolog 2 (EZH2) is an important rheostat of histone H3K27 trimethylation (H3K27me3) that represses endothelial targets, but EZH2 RNA binding capacity and EZH2:RNA functional interactions have not been explored in post-ischemic angiogenesis. We used formaldehyde/UV-assisted crosslinking ligation and sequencing of hybrids and identified a new role for maternally expressed gene 3 (MEG3). MEG3 formed the predominant RNA:RNA hybrid structures in endothelial cells. Moreover, MEG3:EZH2 assists recruitment onto chromatin. By EZH2-chromatin immunoprecipitation, following MEG3 depletion, we demonstrated that MEG3 controls recruitment of EZH2/H3K27me3 onto integrin subunit alpha4 (ITGA4) promoter. Both MEG3 knockdown or EZH2 inhibition (A-395) promoted ITGA4 expression and improved endothelial cell migration and adhesion to fibronectin in vitro. The A-395 inhibitor re-directed MEG3-assisted chromatin remodeling, offering a direct therapeutic benefit by increasing endothelial function and resilience. This approach subsequently increased the expression of ITGA4 in arterioles following ischemic injury in mice, thus promoting arteriogenesis. Our findings show a context-specific role for MEG3 in guiding EZH2 to repress ITGA4. Novel therapeutic strategies could antagonize MEG3:EZH2 interaction for pre-clinical studies.
Collapse
Affiliation(s)
- Hywel Dunn-Davies
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building Max Born Crescent, King’s Buildings, Edinburgh EH9 3BF, UK
| | - Tatiana Dudnakova
- University/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute (QMRI), The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Antonella Nogara
- University/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute (QMRI), The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Julie Rodor
- University/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute (QMRI), The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Anita C. Thomas
- Bristol Medical School, Translational Health Sciences, University of Bristol, Research and Teaching Floor Level 7, Queens Building, Bristol Royal Infirmary, Bristol BS2 8HW, UK
| | - Elisa Parish
- University/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute (QMRI), The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Philippe Gautier
- MRC Human Genetics Unit, MRC Institute of Genetics and Cancer, The University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Alison Meynert
- MRC Human Genetics Unit, MRC Institute of Genetics and Cancer, The University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Igor Ulitsky
- Department of Immunology and Regenerative Biology and Department of Molecular Neuroscience, Weizmann-UK Building rm. 007, Weizmann Institute of Science Rehovot 76100, Israel
| | - Paolo Madeddu
- Bristol Medical School, Translational Health Sciences, University of Bristol, Research and Teaching Floor Level 7, Queens Building, Bristol Royal Infirmary, Bristol BS2 8HW, UK
| | - Andrea Caporali
- University/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute (QMRI), The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Andrew Baker
- University/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute (QMRI), The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - David Tollervey
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building Max Born Crescent, King’s Buildings, Edinburgh EH9 3BF, UK
| | - Tijana Mitić
- University/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute (QMRI), The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| |
Collapse
|
4
|
Gail EH, Healy E, Flanigan SF, Jones N, Ng XH, Uckelmann M, Levina V, Zhang Q, Davidovich C. Inseparable RNA binding and chromatin modification activities of a nucleosome-interacting surface in EZH2. Nat Genet 2024; 56:1193-1202. [PMID: 38744974 PMCID: PMC11176075 DOI: 10.1038/s41588-024-01740-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 04/02/2024] [Indexed: 05/16/2024]
Abstract
Polycomb repressive complex 2 (PRC2) interacts with RNA in cells, but there is no consensus on how RNA regulates PRC2 canonical functions, including chromatin modification and the maintenance of transcription programs in lineage-committed cells. We assayed two separation-of-function mutants of the PRC2 catalytic subunit EZH2, defective in RNA binding but functional in methyltransferase activity. We find that part of the RNA-binding surface of EZH2 is required for chromatin modification, yet this activity is independent of RNA. Mechanistically, the RNA-binding surface within EZH2 is required for chromatin modification in vitro and in cells, through interactions with nucleosomal DNA. Contrarily, an RNA-binding-defective mutant exhibited normal chromatin modification activity in vitro and in lineage-committed cells, accompanied by normal gene repression activity. Collectively, we show that part of the RNA-binding surface of EZH2, rather than the RNA-binding activity per se, is required for the histone methylation in vitro and in cells, through interactions with the substrate nucleosome.
Collapse
Affiliation(s)
- Emma H Gail
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Evan Healy
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Sarena F Flanigan
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Natasha Jones
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Xiao Han Ng
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Michael Uckelmann
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Vitalina Levina
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Qi Zhang
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia.
- South Australian immunoGENomics Cancer Institute (SAiGENCI), Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia.
- EMBL-Australia at SAiGENCI, Adelaide, South Australia, Australia.
| | - Chen Davidovich
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia.
- EMBL-Australia, Clayton, Victoria, Australia.
| |
Collapse
|
5
|
Wang X, Yue F. Hijacked enhancer-promoter and silencer-promoter loops in cancer. Curr Opin Genet Dev 2024; 86:102199. [PMID: 38669773 DOI: 10.1016/j.gde.2024.102199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/19/2024] [Accepted: 04/07/2024] [Indexed: 04/28/2024]
Abstract
Recent work has shown that besides inducing fusion genes, structural variations (SVs) can also contribute to oncogenesis by disrupting the three-dimensional genome organization and dysregulating gene expression. At the chromatin-loop level, SVs can relocate enhancers or silencers from their original genomic loci to activate oncogenes or repress tumor suppressor genes. On a larger scale, different types of alterations in topologically associating domains (TADs) have been reported in cancer, such as TAD expansion, shuffling, and SV-induced neo-TADs. Furthermore, the transformation from normal cells to cancerous cells is usually coupled with active or repressive compartmental switches, and cancer-specific compartments have been proposed. This review discusses the sites, and the other latest advances in studying how SVs disrupt higher-order genome structure in cancer, which in turn leads to oncogene dysregulation. We also highlight the clinical implications of these changes and the challenges ahead in this field.
Collapse
Affiliation(s)
- Xiaotao Wang
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China; Shanghai Key Laboratory of Reproduction and Development, Shanghai, China.
| | - Feng Yue
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine Northwestern University, Chicago, Illinois, USA; Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, Illinois, USA.
| |
Collapse
|
6
|
Zhou T, Zhang L, He L, Lan Y, Ding L, Li L, Wang Z. GSK-126 Attenuates Cell Apoptosis in Ischemic Brain Injury by Modulating the EZH2-H3K27me3-Bcl2l1 Axis. Mol Neurobiol 2024; 61:3369-3383. [PMID: 37989985 DOI: 10.1007/s12035-023-03808-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 11/13/2023] [Indexed: 11/23/2023]
Abstract
Whether epigenetic modifications participate in the cell apoptosis after ischemic stroke remains unclear. Histone 3 tri-methylation at lysine 27 (H3K27me3) is a histone modification that leads to gene silencing and is involved in the pathogenesis of ischemic stroke. Since the expression of many antiapoptotic genes is inhibited in the ischemic brains, here we aimed to offer an epigenetic solution to cell apoptosis after stroke by reversing H3K27me3 levels after ischemia. GSK-126, a specific inhibitor of enhancer of zeste homolog 2 (EZH2), significantly decreased H3K27me3 levels and inhibited middle cerebral artery occlusion (MCAO) induced and oxygen glucose deprivation (OGD) induced cell apoptosis. Moreover, GSK-126 attenuated the apoptosis caused by oxidative stress, excitotoxicity, and excessive inflammatory responses in vitro. The role of H3K27me3 in regulating of the expression of the antiapoptotic molecule B cell lymphoma-2 like 1 (Bcl2l1) explained the antiapoptotic effect of GSK-126. In conclusion, we found that GSK-126 could effectively protect brain cells from apoptosis after cerebral ischemia, and this role of GSK-126 is closely related to an axis that regulates Bcl2l1 expression, beginning with the regulation of EZH2-dependent H3K27me3 modification.
Collapse
Affiliation(s)
- Tai Zhou
- Department of Pathophysiology, School of Basic Medical Sciences, Xuzhou Medical University, Xuzhou, China
| | - Lei Zhang
- Department of Pathophysiology, School of Basic Medical Sciences, Xuzhou Medical University, Xuzhou, China
| | - Li He
- Department of Pathophysiology, School of Basic Medical Sciences, Xuzhou Medical University, Xuzhou, China
| | - Yan Lan
- Department of Pathophysiology, School of Basic Medical Sciences, Xuzhou Medical University, Xuzhou, China
| | - Lei Ding
- Department of Pathophysiology, School of Basic Medical Sciences, Xuzhou Medical University, Xuzhou, China
| | - Li Li
- Department of Pathophysiology, School of Basic Medical Sciences, Xuzhou Medical University, Xuzhou, China.
- Laboratory of Clinical and Experimental Pathology, School of Basic Medical Sciences, Xuzhou Medical University, Xuzhou, China.
| | - Zhongcheng Wang
- Department of Pathophysiology, School of Basic Medical Sciences, Xuzhou Medical University, Xuzhou, China.
- Laboratory of Clinical and Experimental Pathology, School of Basic Medical Sciences, Xuzhou Medical University, Xuzhou, China.
| |
Collapse
|
7
|
Uckelmann M, Davidovich C. Chromatin compaction by Polycomb group proteins revisited. Curr Opin Struct Biol 2024; 86:102806. [PMID: 38537534 DOI: 10.1016/j.sbi.2024.102806] [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: 11/29/2023] [Revised: 02/29/2024] [Accepted: 03/05/2024] [Indexed: 05/19/2024]
Abstract
The chromatin compaction activity of Polycomb group proteins has traditionally been considered essential for transcriptional repression. However, there is very little information on how Polycomb group proteins compact chromatin at the molecular level and no causal link between the compactness of chromatin and transcriptional repression. Recently, a more complete picture of Polycomb-dependent chromatin architecture has started to emerge, owing to advanced methods for imaging and chromosome conformation capture. Discoveries into Polycomb-driven phase separation add another layer of complexity. Recent observations generally imply that Polycomb group proteins modulate chromatin structure at multiple scales to reduce its dynamics and segregate it from active domains. Hence, it is reasonable to hypothesise that Polycomb group proteins maintain the energetically favourable state of compacted chromatin, rather than actively compact it.
Collapse
Affiliation(s)
- Michael Uckelmann
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3800, Australia.
| | - Chen Davidovich
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, 3800, Australia; EMBL-Australia, Clayton, Victoria, 3800, Australia.
| |
Collapse
|
8
|
Zagirova D, Kononkova A, Vaulin N, Khrameeva E. From compartments to loops: understanding the unique chromatin organization in neuronal cells. Epigenetics Chromatin 2024; 17:18. [PMID: 38783373 PMCID: PMC11112951 DOI: 10.1186/s13072-024-00538-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 04/17/2024] [Indexed: 05/25/2024] Open
Abstract
The three-dimensional organization of the genome plays a central role in the regulation of cellular functions, particularly in the human brain. This review explores the intricacies of chromatin organization, highlighting the distinct structural patterns observed between neuronal and non-neuronal brain cells. We integrate findings from recent studies to elucidate the characteristics of various levels of chromatin organization, from differential compartmentalization and topologically associating domains (TADs) to chromatin loop formation. By defining the unique chromatin landscapes of neuronal and non-neuronal brain cells, these distinct structures contribute to the regulation of gene expression specific to each cell type. In particular, we discuss potential functional implications of unique neuronal chromatin organization characteristics, such as weaker compartmentalization, neuron-specific TAD boundaries enriched with active histone marks, and an increased number of chromatin loops. Additionally, we explore the role of Polycomb group (PcG) proteins in shaping cell-type-specific chromatin patterns. This review further emphasizes the impact of variations in chromatin architecture between neuronal and non-neuronal cells on brain development and the onset of neurological disorders. It highlights the need for further research to elucidate the details of chromatin organization in the human brain in order to unravel the complexities of brain function and the genetic mechanisms underlying neurological disorders. This research will help bridge a significant gap in our comprehension of the interplay between chromatin structure and cell functions.
Collapse
Affiliation(s)
- Diana Zagirova
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, Build.1, Moscow, 121205, Russia
- Research and Training Center on Bioinformatics, Institute for Information Transmission Problems (Kharkevich Institute) RAS, Bolshoy Karetny per. 19, Build.1, Moscow, 127051, Russia
| | - Anna Kononkova
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, Build.1, Moscow, 121205, Russia
| | - Nikita Vaulin
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, Build.1, Moscow, 121205, Russia
| | - Ekaterina Khrameeva
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, Build.1, Moscow, 121205, Russia.
| |
Collapse
|
9
|
Le DJ, Hafner A, Gaddam S, Wang KC, Boettiger AN. Super-enhancer interactomes from single cells link clustering and transcription. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.08.593251. [PMID: 38766104 PMCID: PMC11100725 DOI: 10.1101/2024.05.08.593251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Regulation of gene expression hinges on the interplay between enhancers and promoters, traditionally explored through pairwise analyses. Recent advancements in mapping genome folding, like GAM, SPRITE, and multi-contact Hi-C, have uncovered multi-way interactions among super-enhancers (SEs), spanning megabases, yet have not measured their frequency in single cells or the relationship between clustering and transcription. To close this gap, here we used multiplexed imaging to map the 3D positions of 376 SEs across thousands of mammalian nuclei. Notably, our single-cell images reveal that while SE-SE contacts are rare, SEs often form looser associations we termed "communities". These communities, averaging 4-5 SEs, assemble cooperatively under the combined effects of genomic tethers, Pol2 clustering, and nuclear compartmentalization. Larger communities are associated with more frequent and larger transcriptional bursts. Our work provides insights about the SE interactome in single cells that challenge existing hypotheses on SE clustering in the context of transcriptional regulation.
Collapse
Affiliation(s)
- Derek J. Le
- Department of Developmental Biology, Stanford University, Stanford, CA, United States
- Cancer Biology Program, Stanford University, Stanford, CA, United States
- Department of Dermatology, Stanford University, Stanford, CA, United States
- These authors contributed equally
| | - Antonina Hafner
- Department of Developmental Biology, Stanford University, Stanford, CA, United States
- These authors contributed equally
| | - Sadhana Gaddam
- Department of Dermatology, Stanford University, Stanford, CA, United States
| | - Kevin C. Wang
- Department of Dermatology, Stanford University, Stanford, CA, United States
| | - Alistair N. Boettiger
- Department of Developmental Biology, Stanford University, Stanford, CA, United States
- Lead contact
| |
Collapse
|
10
|
Lizana L, Schwartz YB. The scales, mechanisms, and dynamics of the genome architecture. SCIENCE ADVANCES 2024; 10:eadm8167. [PMID: 38598632 PMCID: PMC11006219 DOI: 10.1126/sciadv.adm8167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 03/06/2024] [Indexed: 04/12/2024]
Abstract
Even when split into several chromosomes, DNA molecules that make up our genome are too long to fit into the cell nuclei unless massively folded. Such folding must accommodate the need for timely access to selected parts of the genome by transcription factors, RNA polymerases, and DNA replication machinery. Here, we review our current understanding of the genome folding inside the interphase nuclei. We consider the resulting genome architecture at three scales with a particular focus on the intermediate (meso) scale and summarize the insights gained from recent experimental observations and diverse computational models.
Collapse
Affiliation(s)
- Ludvig Lizana
- Integrated Science Lab, Department of Physics, Umeå University, Umeå, Sweden
| | | |
Collapse
|
11
|
Tang L, Liao J, Hill MC, Hu J, Zhao Y, Ellinor P, Li M. MMCT-Loop: a mix model-based pipeline for calling targeted 3D chromatin loops. Nucleic Acids Res 2024; 52:e25. [PMID: 38281134 PMCID: PMC10954456 DOI: 10.1093/nar/gkae029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 12/03/2023] [Accepted: 01/12/2024] [Indexed: 01/30/2024] Open
Abstract
Protein-specific Chromatin Conformation Capture (3C)-based technologies have become essential for identifying distal genomic interactions with critical roles in gene regulation. The standard techniques include Chromatin Interaction Analysis by Paired-End Tag (ChIA-PET), in situ Hi-C followed by chromatin immunoprecipitation (HiChIP) also known as PLAC-seq. To identify chromatin interactions from these data, a variety of computational methods have emerged. Although these state-of-art methods address many issues with loop calling, only few methods can fit different data types simultaneously, and the accuracy as well as the efficiency these approaches remains limited. Here we have generated a pipeline, MMCT-Loop, which ensures the accurate identification of strong loops as well as dynamic or weak loops through a mixed model. MMCT-Loop outperforms existing methods in accuracy, and the detected loops show higher activation functionality. To highlight the utility of MMCT-Loop, we applied it to conformational data derived from neural stem cell (NSCs) and uncovered several previously unidentified regulatory regions for key master regulators of stem cell identity. MMCT-Loop is an accurate and efficient loop caller for targeted conformation capture data, which supports raw data or pre-processed valid pairs as input, the output interactions are formatted and easily uploaded to a genome browser for visualization.
Collapse
Affiliation(s)
- Li Tang
- Hunan Provincial Key Lab on Bioinformatics, School of Computer Science and Engineering, Central South University, Changsha 410083, China
| | - Jiaqi Liao
- Hunan Provincial Key Lab on Bioinformatics, School of Computer Science and Engineering, Central South University, Changsha 410083, China
| | - Matthew C Hill
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA 02129, USA
- Cardiovascular Disease Initiative, The Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Jiaxin Hu
- Hunan Provincial Key Lab on Bioinformatics, School of Computer Science and Engineering, Central South University, Changsha 410083, China
| | - Yichao Zhao
- Hunan Provincial Key Lab on Bioinformatics, School of Computer Science and Engineering, Central South University, Changsha 410083, China
| | - Patrick T Ellinor
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA 02129, USA
- Cardiovascular Disease Initiative, The Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Min Li
- Hunan Provincial Key Lab on Bioinformatics, School of Computer Science and Engineering, Central South University, Changsha 410083, China
| |
Collapse
|
12
|
Del Blanco B, Niñerola S, Martín-González AM, Paraíso-Luna J, Kim M, Muñoz-Viana R, Racovac C, Sanchez-Mut JV, Ruan Y, Barco Á. Kdm1a safeguards the topological boundaries of PRC2-repressed genes and prevents aging-related euchromatinization in neurons. Nat Commun 2024; 15:1781. [PMID: 38453932 PMCID: PMC10920760 DOI: 10.1038/s41467-024-45773-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 02/02/2024] [Indexed: 03/09/2024] Open
Abstract
Kdm1a is a histone demethylase linked to intellectual disability with essential roles during gastrulation and the terminal differentiation of specialized cell types, including neurons, that remains highly expressed in the adult brain. To explore Kdm1a's function in adult neurons, we develop inducible and forebrain-restricted Kdm1a knockouts. By applying multi-omic transcriptome, epigenome and chromatin conformation data, combined with super-resolution microscopy, we find that Kdm1a elimination causes the neuronal activation of nonneuronal genes that are silenced by the polycomb repressor complex and interspersed with active genes. Functional assays demonstrate that the N-terminus of Kdm1a contains an intrinsically disordered region that is essential to segregate Kdm1a-repressed genes from the neighboring active chromatin environment. Finally, we show that the segregation of Kdm1a-target genes is weakened in neurons during natural aging, underscoring the role of Kdm1a safeguarding neuronal genome organization and gene silencing throughout life.
Collapse
Affiliation(s)
- Beatriz Del Blanco
- Instituto de Neurociencias (Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant, 03550, Alicante, Spain.
| | - Sergio Niñerola
- Instituto de Neurociencias (Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant, 03550, Alicante, Spain
| | - Ana M Martín-González
- Instituto de Neurociencias (Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant, 03550, Alicante, Spain
| | - Juan Paraíso-Luna
- Instituto de Neurociencias (Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant, 03550, Alicante, Spain
- Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Minji Kim
- The Jackson laboratory for Genomic Medicine, Farmington, CT, 06030, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Rafael Muñoz-Viana
- Instituto de Neurociencias (Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant, 03550, Alicante, Spain
- Bioinformatics Unit, Hospital universitario Puerta de Hierro Majadahonda, 28220, Majadahonda, Spain
| | - Carina Racovac
- Instituto de Neurociencias (Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant, 03550, Alicante, Spain
| | - Jose V Sanchez-Mut
- Instituto de Neurociencias (Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant, 03550, Alicante, Spain
| | - Yijun Ruan
- The Jackson laboratory for Genomic Medicine, Farmington, CT, 06030, USA
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang Province, 310058, P.R. China
| | - Ángel Barco
- Instituto de Neurociencias (Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant, 03550, Alicante, Spain.
| |
Collapse
|
13
|
Murphy SE, Boettiger AN. Polycomb repression of Hox genes involves spatial feedback but not domain compaction or phase transition. Nat Genet 2024; 56:493-504. [PMID: 38361032 DOI: 10.1038/s41588-024-01661-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 01/10/2024] [Indexed: 02/17/2024]
Abstract
Polycomb group proteins have a critical role in silencing transcription during development. It is commonly proposed that Polycomb-dependent changes in genome folding, which compact chromatin, contribute directly to repression by blocking the binding of activating complexes. Recently, it has also been argued that liquid-liquid demixing of Polycomb proteins facilitates this compaction and repression by phase-separating target genes into a membraneless compartment. To test these models, we used Optical Reconstruction of Chromatin Architecture to trace the Hoxa gene cluster, a canonical Polycomb target, in thousands of single cells. Across multiple cell types, we find that Polycomb-bound chromatin frequently explores decompact states and partial mixing with neighboring chromatin, while remaining uniformly repressed, challenging the repression-by-compaction or phase-separation models. Using polymer simulations, we show that these observed flexible ensembles can be explained by 'spatial feedback'-transient contacts that contribute to the propagation of the epigenetic state (epigenetic memory), without inducing a globular organization.
Collapse
Affiliation(s)
- Sedona Eve Murphy
- Department of Genetics, Stanford University, Stanford, CA, USA
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
- Department of Cell Biology, Yale University, New Haven, CT, USA
| | | |
Collapse
|
14
|
Monteagudo-Sánchez A, Noordermeer D, Greenberg MVC. The impact of DNA methylation on CTCF-mediated 3D genome organization. Nat Struct Mol Biol 2024; 31:404-412. [PMID: 38499830 DOI: 10.1038/s41594-024-01241-6] [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: 12/19/2022] [Accepted: 02/05/2024] [Indexed: 03/20/2024]
Abstract
Cytosine DNA methylation is a highly conserved epigenetic mark in eukaryotes. Although the role of DNA methylation at gene promoters and repetitive elements has been extensively studied, the function of DNA methylation in other genomic contexts remains less clear. In the nucleus of mammalian cells, the genome is spatially organized at different levels, and strongly influences myriad genomic processes. There are a number of factors that regulate the three-dimensional (3D) organization of the genome, with the CTCF insulator protein being among the most well-characterized. Pertinently, CTCF binding has been reported as being DNA methylation-sensitive in certain contexts, perhaps most notably in the process of genomic imprinting. Therefore, it stands to reason that DNA methylation may play a broader role in the regulation of chromatin architecture. Here we summarize the current understanding that is relevant to both the mammalian DNA methylation and chromatin architecture fields and attempt to assess the extent to which DNA methylation impacts the folding of the genome. The focus is in early embryonic development and cellular transitions when the epigenome is in flux, but we also describe insights from pathological contexts, such as cancer, in which the epigenome and 3D genome organization are misregulated.
Collapse
Affiliation(s)
| | - Daan Noordermeer
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | | |
Collapse
|
15
|
Ingersoll S, Trouth A, Luo X, Espinoza A, Wen J, Tucker J, Astatike K, Phiel CJ, Kutateladze TG, Wu TP, Ramachandran S, Ren X. Sparse CBX2 nucleates many Polycomb proteins to promote facultative heterochromatinization of Polycomb target genes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.05.578969. [PMID: 38370615 PMCID: PMC10871256 DOI: 10.1101/2024.02.05.578969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Facultative heterochromatinization of genomic regulators by Polycomb repressive complex (PRC) 1 and 2 is essential in development and differentiation; however, the underlying molecular mechanisms remain obscure. Using genetic engineering, molecular approaches, and live-cell single-molecule imaging, we quantify the number of proteins within condensates formed through liquid-liquid phase separation (LLPS) and find that in mouse embryonic stem cells (mESCs), approximately 3 CBX2 proteins nucleate many PRC1 and PRC2 subunits to form one non-stoichiometric condensate. We demonstrate that sparse CBX2 prevents Polycomb proteins from migrating to constitutive heterochromatin, demarcates the spatial boundaries of facultative heterochromatin, controls the deposition of H3K27me3, regulates transcription, and impacts cellular differentiation. Furthermore, we show that LLPS of CBX2 is required for the demarcation and deposition of H3K27me3 and is essential for cellular differentiation. Our findings uncover new functional roles of LLPS in the formation of facultative heterochromatin and unravel a new mechanism by which low-abundant proteins nucleate many other proteins to form compartments that enable them to execute their functions.
Collapse
Affiliation(s)
- Steven Ingersoll
- Department of Chemistry, University of Colorado Denver, Denver, CO 80217-3364, USA
| | - Abby Trouth
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Xinlong Luo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Axel Espinoza
- Department of Integrative Biology, University of Colorado Denver, CO 80217-3364, USA
| | - Joey Wen
- Department of Chemistry, University of Colorado Denver, Denver, CO 80217-3364, USA
| | - Joseph Tucker
- Department of Integrative Biology, University of Colorado Denver, CO 80217-3364, USA
| | - Kalkidan Astatike
- Department of Chemistry, University of Colorado Denver, Denver, CO 80217-3364, USA
| | - Christopher J. Phiel
- Department of Integrative Biology, University of Colorado Denver, CO 80217-3364, USA
| | - Tatiana G. Kutateladze
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Tao P. Wu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Srinivas Ramachandran
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, USA
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO, USA
| | - Xiaojun Ren
- Department of Chemistry, University of Colorado Denver, Denver, CO 80217-3364, USA
- Department of Integrative Biology, University of Colorado Denver, CO 80217-3364, USA
| |
Collapse
|
16
|
Hua D, Gu M, Zhang X, Du Y, Xie H, Qi L, Du X, Bai Z, Zhu X, Tian D. DiffDomain enables identification of structurally reorganized topologically associating domains. Nat Commun 2024; 15:502. [PMID: 38218905 PMCID: PMC10787792 DOI: 10.1038/s41467-024-44782-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 01/02/2024] [Indexed: 01/15/2024] Open
Abstract
Topologically associating domains (TADs) are critical structural units in three-dimensional genome organization of mammalian genome. Dynamic reorganizations of TADs between health and disease states are associated with essential genome functions. However, computational methods for identifying reorganized TADs are still in the early stages of development. Here, we present DiffDomain, an algorithm leveraging high-dimensional random matrix theory to identify structurally reorganized TADs using high-throughput chromosome conformation capture (Hi-C) contact maps. Method comparison using multiple real Hi-C datasets reveals that DiffDomain outperforms alternative methods for false positive rates, true positive rates, and identifying a new subtype of reorganized TADs. Applying DiffDomain to Hi-C data from different cell types and disease states demonstrates its biological relevance. Identified reorganized TADs are associated with structural variations and epigenomic changes such as changes in CTCF binding sites. By applying to a single-cell Hi-C data from mouse neuronal development, DiffDomain can identify reorganized TADs between cell types with reasonable reproducibility using pseudo-bulk Hi-C data from as few as 100 cells per condition. Moreover, DiffDomain reveals differential cell-to-population variability and heterogeneous cell-to-cell variability in TADs. Therefore, DiffDomain is a statistically sound method for better comparative analysis of TADs using both Hi-C and single-cell Hi-C data.
Collapse
Affiliation(s)
- Dunming Hua
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Ming Gu
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Xiao Zhang
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Yanyi Du
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Hangcheng Xie
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Li Qi
- Chongqing Municipal Center for Disease Control and Prevention, Chongqing, 400042, China
| | - Xiangjun Du
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Zhidong Bai
- KLASMOE & School of Mathematics and Statistics, Northeast Normal University, Changchun, Jilin, 130024, China
| | - Xiaopeng Zhu
- MyCellome LLC., Allison Park, PA, 15101, USA
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Dechao Tian
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, 510275, China.
- Department of Biostatistics and Systems Biology, School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China.
| |
Collapse
|
17
|
Han MH, Issagulova D, Park M. Interplay between epigenome and 3D chromatin structure. BMB Rep 2023; 56:633-644. [PMID: 38052424 PMCID: PMC10761748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/28/2023] [Accepted: 12/05/2023] [Indexed: 12/07/2023] Open
Abstract
Epigenetic mechanisms, primarily mediated through histone and DNA modifications, play a pivotal role in orchestrating the functional identity of a cell and its response to environmental cues. Similarly, the spatial arrangement of chromatin within the threedimensional (3D) nucleus has been recognized as a significant factor influencing genomic function. Investigating the relationship between epigenetic regulation and 3D chromatin structure has revealed correlation and causality between these processes, from the global alignment of average chromatin structure with chromatin marks to the nuanced correlations at smaller scales. This review aims to dissect the biological significance and the interplay between the epigenome and 3D chromatin structure, while also exploring the underlying molecular mechanisms. By synthesizing insights from both experimental and modeling perspectives, we seek to provide a comprehensive understanding of cellular functions. [BMB Reports 2023; 56(12): 633-644].
Collapse
Affiliation(s)
- Man-Hyuk Han
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Dariya Issagulova
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Minhee Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; Graduate School of Engineering Biology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141; KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141; KAIST Stem Cell Center, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| |
Collapse
|
18
|
Singh A, Chakrabarti S. Diffusion controls local versus dispersed inheritance of histones during replication and shapes epigenomic architecture. PLoS Comput Biol 2023; 19:e1011725. [PMID: 38109423 PMCID: PMC10760866 DOI: 10.1371/journal.pcbi.1011725] [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: 07/24/2023] [Revised: 01/02/2024] [Accepted: 12/01/2023] [Indexed: 12/20/2023] Open
Abstract
The dynamics of inheritance of histones and their associated modifications across cell divisions can have major consequences on maintenance of the cellular epigenomic state. Recent experiments contradict the long-held notion that histone inheritance during replication is always local, suggesting that active and repressed regions of the genome exhibit fundamentally different histone dynamics independent of transcription-coupled turnover. Here we develop a stochastic model of histone dynamics at the replication fork and demonstrate that differential diffusivity of histones in active versus repressed chromatin is sufficient to quantitatively explain these recent experiments. Further, we use the model to predict patterns in histone mark similarity between pairs of genomic loci that should be developed as a result of diffusion, but cannot originate from either PRC2 mediated mark spreading or transcriptional processes. Interestingly, using a combination of CHIP-seq, replication timing and Hi-C datasets we demonstrate that all the computationally predicted patterns are consistently observed for both active and repressive histone marks in two different cell lines. While direct evidence for histone diffusion remains controversial, our results suggest that dislodged histones in euchromatin and facultative heterochromatin may exhibit some level of diffusion within "Diffusion-Accessible-Domains" (DADs), leading to redistribution of epigenetic marks within and across chromosomes. Preservation of the epigenomic state across cell divisions therefore might be achieved not by passing on strict positional information of histone marks, but by maintaining the marks in somewhat larger DADs of the genome.
Collapse
Affiliation(s)
- Archit Singh
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Shaon Chakrabarti
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| |
Collapse
|
19
|
Cai L, Wang GG. Through the lens of phase separation: intrinsically unstructured protein and chromatin looping. Nucleus 2023; 14:2179766. [PMID: 36821650 PMCID: PMC9980480 DOI: 10.1080/19491034.2023.2179766] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
The establishment, maintenance and dynamic regulation of three-dimensional (3D) chromatin structures provide an important means for partitioning of genome into functionally distinctive domains, which helps to define specialized gene expression programs associated with developmental stages and cell types. Increasing evidence supports critical roles for intrinsically disordered regions (IDRs) harbored within transcription factors (TFs) and chromatin-modulatory proteins in inducing phase separation, a phenomenon of forming membrane-less condensates through partitioning of biomolecules. Such a process is also critically involved in the establishment of high-order chromatin structures and looping. IDR- and phase separation-driven 3D genome (re)organization often goes wrong in disease such as cancer. This review discusses about recent advances in understanding how phase separation of intrinsically disordered proteins (IDPs) modulates chromatin looping and gene expression.
Collapse
Affiliation(s)
- Ling Cai
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA,Department of Genetics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA,Ling Cai Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC27599, USA
| | - Gang Greg Wang
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA,Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA,CONTACT Gang Greg Wang Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC27599, USA
| |
Collapse
|
20
|
Krug B, Hu B, Chen H, Ptack A, Chen X, Gretarsson KH, Deshmukh S, Kabir N, Andrade AF, Jabbour E, Harutyunyan AS, Lee JJY, Hulswit M, Faury D, Russo C, Xu X, Johnston MJ, Baguette A, Dahl NA, Weil AG, Ellezam B, Dali R, Blanchette M, Wilson K, Garcia BA, Soni RK, Gallo M, Taylor MD, Kleinman CL, Majewski J, Jabado N, Lu C. H3K27me3 spreading organizes canonical PRC1 chromatin architecture to regulate developmental programs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.28.567931. [PMID: 38116029 PMCID: PMC10729739 DOI: 10.1101/2023.11.28.567931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Polycomb Repressive Complex 2 (PRC2)-mediated histone H3K27 tri-methylation (H3K27me3) recruits canonical PRC1 (cPRC1) to maintain heterochromatin. In early development, polycomb-regulated genes are connected through long-range 3D interactions which resolve upon differentiation. Here, we report that polycomb looping is controlled by H3K27me3 spreading and regulates target gene silencing and cell fate specification. Using glioma-derived H3 Lys-27-Met (H3K27M) mutations as tools to restrict H3K27me3 deposition, we show that H3K27me3 confinement concentrates the chromatin pool of cPRC1, resulting in heightened 3D interactions mirroring chromatin architecture of pluripotency, and stringent gene repression that maintains cells in progenitor states to facilitate tumor development. Conversely, H3K27me3 spread in pluripotent stem cells, following neural differentiation or loss of the H3K36 methyltransferase NSD1, dilutes cPRC1 concentration and dissolves polycomb loops. These results identify the regulatory principles and disease implications of polycomb looping and nominate histone modification-guided distribution of reader complexes as an important mechanism for nuclear compartment organization. Highlights The confinement of H3K27me3 at PRC2 nucleation sites without its spreading correlates with increased 3D chromatin interactions.The H3K27M oncohistone concentrates canonical PRC1 that anchors chromatin loop interactions in gliomas, silencing developmental programs.Stem and progenitor cells require factors promoting H3K27me3 confinement, including H3K36me2, to maintain cPRC1 loop architecture.The cPRC1-H3K27me3 interaction is a targetable driver of aberrant self-renewal in tumor cells.
Collapse
|
21
|
Owen JA, Osmanović D, Mirny L. Design principles of 3D epigenetic memory systems. Science 2023; 382:eadg3053. [PMID: 37972190 PMCID: PMC11075759 DOI: 10.1126/science.adg3053] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 09/28/2023] [Indexed: 11/19/2023]
Abstract
Cells remember their identities, in part, by using epigenetic marks-chemical modifications placed along the genome. How can mark patterns remain stable over cell generations despite their constant erosion by replication and other processes? We developed a theoretical model that reveals that three-dimensional (3D) genome organization can stabilize epigenetic memory as long as (i) there is a large density difference between chromatin compartments, (ii) modifying "reader-writer" enzymes spread marks in three dimensions, and (iii) the enzymes are limited in abundance relative to their histone substrates. Analogous to an associative memory that encodes memory in neuronal connectivity, mark patterns are encoded in a 3D network of chromosomal contacts. Our model provides a unified account of diverse observations and reveals a key role of 3D genome organization in epigenetic memory.
Collapse
Affiliation(s)
- Jeremy A. Owen
- Department of Physics, Massachusetts Institute of Technology; Cambridge, USA
| | - Dino Osmanović
- Department of Mechanical and Aeronautical Engineering, UCLA; Los Angeles, USA
| | - Leonid Mirny
- Department of Physics, Massachusetts Institute of Technology; Cambridge, USA
| |
Collapse
|
22
|
Rahman S, Dong P, Apontes P, Fernando M, Kosoy R, Townsley KG, Girdhar K, Bendl J, Shao Z, Misir R, Tsankova N, Kleopoulos S, Brennand K, Fullard J, Roussos P. Lineage specific 3D genome structure in the adult human brain and neurodevelopmental changes in the chromatin interactome. Nucleic Acids Res 2023; 51:11142-11161. [PMID: 37811875 PMCID: PMC10639075 DOI: 10.1093/nar/gkad798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 08/18/2023] [Accepted: 09/19/2023] [Indexed: 10/10/2023] Open
Abstract
The human brain is a complex organ comprised of distinct cell types, and the contribution of the 3D genome to lineage specific gene expression remains poorly understood. To decipher cell type specific genome architecture, and characterize fine scale changes in the chromatin interactome across neural development, we compared the 3D genome of the human fetal cortical plate to that of neurons and glia isolated from the adult prefrontal cortex. We found that neurons have weaker genome compartmentalization compared to glia, but stronger TADs, which emerge during fetal development. Furthermore, relative to glia, the neuronal genome shifts more strongly towards repressive compartments. Neurons have differential TAD boundaries that are proximal to active promoters involved in neurodevelopmental processes. CRISPRi on CNTNAP2 in hIPSC-derived neurons reveals that transcriptional inactivation correlates with loss of insulation at the differential boundary. Finally, re-wiring of chromatin loops during neural development is associated with transcriptional and functional changes. Importantly, differential loops in the fetal cortex are associated with autism GWAS loci, suggesting a neuropsychiatric disease mechanism affecting the chromatin interactome. Furthermore, neural development involves gaining enhancer-promoter loops that upregulate genes that control synaptic activity. Altogether, our study provides multi-scale insights on the 3D genome in the human brain.
Collapse
Affiliation(s)
- Samir Rahman
- Center for Disease Neurogenomics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Pengfei Dong
- Center for Disease Neurogenomics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Pasha Apontes
- Center for Disease Neurogenomics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Mental Illness Research Education and Clinical Center (MIRECC), James J. Peters VA Medical Center, Bronx, NY 10468, USA
| | - Michael B Fernando
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Roman Kosoy
- Center for Disease Neurogenomics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Kayla G Townsley
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Kiran Girdhar
- Center for Disease Neurogenomics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jaroslav Bendl
- Center for Disease Neurogenomics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Zhiping Shao
- Center for Disease Neurogenomics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ruth Misir
- Center for Disease Neurogenomics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Nadia Tsankova
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Pathology, Molecular, and Cell-based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Steven P Kleopoulos
- Center for Disease Neurogenomics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Kristen J Brennand
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - John F Fullard
- Center for Disease Neurogenomics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Panos Roussos
- Center for Disease Neurogenomics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Mental Illness Research Education and Clinical Center (MIRECC), James J. Peters VA Medical Center, Bronx, NY 10468, USA
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| |
Collapse
|
23
|
Serdyukova K, Swearingen AR, Coradin M, Nevo M, Tran H, Bajric E, Brumbaugh J. Leveraging dominant-negative histone H3 K-to-M mutations to study chromatin during differentiation and development. Development 2023; 150:dev202169. [PMID: 38771302 PMCID: PMC10617616 DOI: 10.1242/dev.202169] [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: 10/18/2023]
Abstract
Histone modifications are associated with regulation of gene expression that controls a vast array of biological processes. Often, these associations are drawn by correlating the genomic location of a particular histone modification with gene expression or phenotype; however, establishing a causal relationship between histone marks and biological processes remains challenging. Consequently, there is a strong need for experimental approaches to directly manipulate histone modifications. A class of mutations on the N-terminal tail of histone H3, lysine-to-methionine (K-to-M) mutations, was identified as dominant-negative inhibitors of histone methylation at their respective and specific residues. The dominant-negative nature of K-to-M mutants makes them a valuable tool for studying the function of specific methylation marks on histone H3. Here, we review recent applications of K-to-M mutations to understand the role of histone methylation during development and homeostasis. We highlight important advantages and limitations that require consideration when using K-to-M mutants, particularly in a developmental context.
Collapse
Affiliation(s)
- Ksenia Serdyukova
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
- University of Colorado Cancer Center, Anschutz Medical Campus, Aurora, CO 80045, USA
- Charles C. Gates Center for Regenerative Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Alison R. Swearingen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
- University of Colorado Cancer Center, Anschutz Medical Campus, Aurora, CO 80045, USA
- Charles C. Gates Center for Regenerative Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Mariel Coradin
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
- University of Colorado Cancer Center, Anschutz Medical Campus, Aurora, CO 80045, USA
- Charles C. Gates Center for Regenerative Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Mika Nevo
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
- University of Colorado Cancer Center, Anschutz Medical Campus, Aurora, CO 80045, USA
- Charles C. Gates Center for Regenerative Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Huong Tran
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
- University of Colorado Cancer Center, Anschutz Medical Campus, Aurora, CO 80045, USA
- Charles C. Gates Center for Regenerative Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Emir Bajric
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
- University of Colorado Cancer Center, Anschutz Medical Campus, Aurora, CO 80045, USA
- Charles C. Gates Center for Regenerative Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Justin Brumbaugh
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
- University of Colorado Cancer Center, Anschutz Medical Campus, Aurora, CO 80045, USA
- Charles C. Gates Center for Regenerative Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| |
Collapse
|
24
|
Negri ML, D'Annunzio S, Vitali G, Zippo A. May the force be with you: Nuclear condensates function beyond transcription control: Potential nongenetic functions of nuclear condensates in physiological and pathological conditions. Bioessays 2023; 45:e2300075. [PMID: 37530178 DOI: 10.1002/bies.202300075] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 07/03/2023] [Accepted: 07/13/2023] [Indexed: 08/03/2023]
Abstract
Over the past decade, research has revealed biomolecular condensates' relevance in diverse cellular functions. Through a phase separation process, they concentrate macromolecules in subcompartments shaping the cellular organization and physiology. In the nucleus, biomolecular condensates assemble relevant biomolecules that orchestrate gene expression. We here hypothesize that chromatin condensates can also modulate the nongenetic functions of the genome, including the nuclear mechanical properties. The importance of chromatin condensates is supported by the genetic evidence indicating that mutations in their members are causative of a group of rare Mendelian diseases named chromatinopathies (CPs). Despite a broad spectrum of clinical features and the perturbations of the epigenetic machinery characterizing the CPs, recent findings highlighted negligible changes in gene expression. These data argue in favor of possible noncanonical functions of chromatin condensates in regulating the genome's spatial organization and, consequently, the nuclear mechanics. In this review, we discuss how condensates may impact nuclear mechanical properties, thus affecting the cellular response to mechanical cues and, eventually, cell fate and identity. Chromatin condensates organize macromolecules in the nucleus orchestrating the transcription regulation and mutations in their members are responsible for rare diseases named chromatinopathies. We argue that chromatin condensates, in concert with the nuclear lamina, may also govern the nuclear mechanical properties affecting the cellular response to external cues.
Collapse
Affiliation(s)
- Maria Luce Negri
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Sarah D'Annunzio
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Giulia Vitali
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Alessio Zippo
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| |
Collapse
|
25
|
Sun L, Cao Y, Li Z, Liu Y, Yin X, Deng XW, He H, Qian W. Conserved H3K27me3-associated chromatin looping mediates physical interactions of gene clusters in plants. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023; 65:1966-1982. [PMID: 37154484 DOI: 10.1111/jipb.13502] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/26/2023] [Accepted: 05/06/2023] [Indexed: 05/10/2023]
Abstract
Higher-order chromatin organization is essential for transcriptional regulation, genome stability maintenance, and other genome functions. Increasing evidence has revealed significant differences in 3D chromatin organization between plants and animals. However, the extent, pattern, and rules of chromatin organization in plants are still unclear. In this study, we systematically identified and characterized long-range chromatin loops in the Arabidopsis 3D genome. We identified hundreds of long-range cis chromatin loops and found their anchor regions are closely associated with H3K27me3 epigenetic modifications. Furthermore, we demonstrated that these chromatin loops are dependent on Polycomb group (PcG) proteins, suggesting that the Polycomb repressive complex 2 (PRC2) complex is essential for establishing and maintaining these novel loops. Although most of these PcG-medicated chromatin loops are stable, many of these loops are tissue-specific or dynamically regulated by different treatments. Interestingly, tandemly arrayed gene clusters and metabolic gene clusters are enriched in anchor regions. Long-range H3K27me3-marked chromatin interactions are associated with the coregulation of specific gene clusters. Finally, we also identified H3K27me3-associated chromatin loops associated with gene clusters in Oryza sativa and Glycine max, indicating that these long-range chromatin loops are conserved in plants. Our results provide novel insights into genome evolution and transcriptional coregulation in plants.
Collapse
Affiliation(s)
- Linhua Sun
- National Key Laboratory of Wheat Improvement, Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences in Weifang, Weifang, 261325, China
- School of Advanced Agriculture Sciences, Peking University, Beijing, 100871, China
| | - Yuxin Cao
- School of Advanced Agriculture Sciences, Peking University, Beijing, 100871, China
| | - Zhu Li
- National Key Laboratory of Wheat Improvement, Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences in Weifang, Weifang, 261325, China
- School of Plant Science and Food Security, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Yi Liu
- School of Advanced Agriculture Sciences, Peking University, Beijing, 100871, China
| | - Xiaochang Yin
- School of Advanced Agriculture Sciences, Peking University, Beijing, 100871, China
| | - Xing Wang Deng
- National Key Laboratory of Wheat Improvement, Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences in Weifang, Weifang, 261325, China
- School of Advanced Agriculture Sciences, Peking University, Beijing, 100871, China
| | - Hang He
- National Key Laboratory of Wheat Improvement, Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences in Weifang, Weifang, 261325, China
- School of Advanced Agriculture Sciences, Peking University, Beijing, 100871, China
| | - Weiqiang Qian
- National Key Laboratory of Wheat Improvement, Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences in Weifang, Weifang, 261325, China
- School of Advanced Agriculture Sciences, Peking University, Beijing, 100871, China
| |
Collapse
|
26
|
Braceros AK, Schertzer MD, Omer A, Trotman JB, Davis ES, Dowen JM, Phanstiel DH, Aiden EL, Calabrese JM. Proximity-dependent recruitment of Polycomb repressive complexes by the lncRNA Airn. Cell Rep 2023; 42:112803. [PMID: 37436897 PMCID: PMC10441531 DOI: 10.1016/j.celrep.2023.112803] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 05/10/2023] [Accepted: 06/26/2023] [Indexed: 07/14/2023] Open
Abstract
During mouse embryogenesis, expression of the long non-coding RNA (lncRNA) Airn leads to gene repression and recruitment of Polycomb repressive complexes (PRCs) to varying extents over a 15-Mb domain. The mechanisms remain unclear. Using high-resolution approaches, we show in mouse trophoblast stem cells that Airn expression induces long-range changes to chromatin architecture that coincide with PRC-directed modifications and center around CpG island promoters that contact the Airn locus even in the absence of Airn expression. Intensity of contact between the Airn lncRNA and chromatin correlated with underlying intensity of PRC recruitment and PRC-directed modifications. Deletion of CpG islands that contact the Airn locus altered long-distance repression and PRC activity in a manner that correlated with changes in chromatin architecture. Our data imply that the extent to which Airn expression recruits PRCs to chromatin is controlled by DNA regulatory elements that modulate proximity of the Airn lncRNA product to its target DNA.
Collapse
Affiliation(s)
- Aki K Braceros
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA; RNA Discovery Center, University of North Carolina, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Mechanistic, Interdisciplinary Studies of Biological Systems, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Megan D Schertzer
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA; Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Arina Omer
- Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jackson B Trotman
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA; RNA Discovery Center, University of North Carolina, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, 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
| | - Jill M Dowen
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA; Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Douglas H Phanstiel
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA; 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; Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA; Thurston Arthritis Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Erez Lieberman Aiden
- Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - J Mauro Calabrese
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA; RNA Discovery Center, University of North Carolina, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA.
| |
Collapse
|
27
|
Hafner A, Park M, Berger SE, Murphy SE, Nora EP, Boettiger AN. Loop stacking organizes genome folding from TADs to chromosomes. Mol Cell 2023; 83:1377-1392.e6. [PMID: 37146570 PMCID: PMC10167645 DOI: 10.1016/j.molcel.2023.04.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 02/17/2023] [Accepted: 04/06/2023] [Indexed: 05/07/2023]
Abstract
Although population-level analyses revealed significant roles for CTCF and cohesin in mammalian genome organization, their contributions at the single-cell level remain incompletely understood. Here, we used a super-resolution microscopy approach to measure the effects of removal of CTCF or cohesin in mouse embryonic stem cells. Single-chromosome traces revealed cohesin-dependent loops, frequently stacked at their loop anchors forming multi-way contacts (hubs), bridging across TAD boundaries. Despite these bridging interactions, chromatin in intervening TADs was not intermixed, remaining separated in distinct loops around the hub. At the multi-TAD scale, steric effects from loop stacking insulated local chromatin from ultra-long range (>4 Mb) contacts. Upon cohesin removal, the chromosomes were more disordered and increased cell-cell variability in gene expression. Our data revise the TAD-centric understanding of CTCF and cohesin and provide a multi-scale, structural picture of how they organize the genome on the single-cell level through distinct contributions to loop stacking.
Collapse
Affiliation(s)
- Antonina Hafner
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
| | - Minhee Park
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
| | - Scott E Berger
- Biophysics Program, Stanford University, Stanford, CA, USA
| | - Sedona E Murphy
- Department of Developmental Biology, Stanford University, Stanford, CA, USA; Department of Genetics, Stanford University, Stanford, CA, USA
| | - Elphège P Nora
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA; Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | | |
Collapse
|
28
|
Uyehara CM, Apostolou E. 3D enhancer-promoter interactions and multi-connected hubs: Organizational principles and functional roles. Cell Rep 2023; 42:112068. [PMID: 37059094 PMCID: PMC10556201 DOI: 10.1016/j.celrep.2023.112068] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/25/2022] [Accepted: 01/20/2023] [Indexed: 04/16/2023] Open
Abstract
The spatiotemporal control of gene expression is dependent on the activity of cis-acting regulatory sequences, called enhancers, which regulate target genes over variable genomic distances and, often, by skipping intermediate promoters, suggesting mechanisms that control enhancer-promoter communication. Recent genomics and imaging technologies have revealed highly complex enhancer-promoter interaction networks, whereas advanced functional studies have started interrogating the forces behind the physical and functional communication among multiple enhancers and promoters. In this review, we first summarize our current understanding of the factors involved in enhancer-promoter communication, with a particular focus on recent papers that have revealed new layers of complexities to old questions. In the second part of the review, we focus on a subset of highly connected enhancer-promoter "hubs" and discuss their potential functions in signal integration and gene regulation, as well as the putative factors that might determine their dynamics and assembly.
Collapse
Affiliation(s)
- Christopher M Uyehara
- Sanford I. Weill Department of Medicine, Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Effie Apostolou
- Sanford I. Weill Department of Medicine, Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA.
| |
Collapse
|
29
|
Ramesh V, Liu F, Minto MS, Chan U, West AE. Bidirectional regulation of postmitotic H3K27me3 distributions underlie cerebellar granule neuron maturation dynamics. eLife 2023; 12:e86273. [PMID: 37092728 PMCID: PMC10181825 DOI: 10.7554/elife.86273] [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: 01/18/2023] [Accepted: 04/21/2023] [Indexed: 04/25/2023] Open
Abstract
The functional maturation of neurons is a prolonged process that extends past the mitotic exit and is mediated by the chromatin-dependent orchestration of gene transcription programs. We find that expression of this maturation gene program in mouse cerebellar granule neurons (CGNs) requires dynamic changes in the genomic distribution of histone H3 lysine 27 trimethylation (H3K27me3), demonstrating a function for this chromatin modification beyond its role in cell fate specification. The developmental loss of H3K27me3 at promoters of genes activated as CGNs mature is facilitated by the lysine demethylase and ASD-risk gene, Kdm6b. Interestingly, inhibition of the H3K27 methyltransferase EZH2 in newborn CGNs not only blocks the repression of progenitor genes but also impairs the induction of mature CGN genes, showing the importance of bidirectional H3K27me3 regulation across the genome. These data demonstrate that H3K27me3 turnover in developing postmitotic neurons regulates the temporal coordination of gene expression programs that underlie functional neuronal maturation.
Collapse
Affiliation(s)
- Vijyendra Ramesh
- Molecular Cancer Biology Program, Duke UniversityDurhamUnited States
| | - Fang Liu
- Department of Neurobiology, Duke UniversityDurhamUnited States
| | - Melyssa S Minto
- Department of Neurobiology, Duke UniversityDurhamUnited States
| | - Urann Chan
- Department of Neurobiology, Duke UniversityDurhamUnited States
| | - Anne E West
- Molecular Cancer Biology Program, Duke UniversityDurhamUnited States
- Department of Neurobiology, Duke UniversityDurhamUnited States
| |
Collapse
|
30
|
Kim S, Wysocka J. Deciphering the multi-scale, quantitative cis-regulatory code. Mol Cell 2023; 83:373-392. [PMID: 36693380 PMCID: PMC9898153 DOI: 10.1016/j.molcel.2022.12.032] [Citation(s) in RCA: 57] [Impact Index Per Article: 57.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/29/2022] [Accepted: 12/30/2022] [Indexed: 01/24/2023]
Abstract
Uncovering the cis-regulatory code that governs when and how much each gene is transcribed in a given genome and cellular state remains a central goal of biology. Here, we discuss major layers of regulation that influence how transcriptional outputs are encoded by DNA sequence and cellular context. We first discuss how transcription factors bind specific DNA sequences in a dosage-dependent and cooperative manner and then proceed to the cofactors that facilitate transcription factor function and mediate the activity of modular cis-regulatory elements such as enhancers, silencers, and promoters. We then consider the complex and poorly understood interplay of these diverse elements within regulatory landscapes and its relationships with chromatin states and nuclear organization. We propose that a mechanistically informed, quantitative model of transcriptional regulation that integrates these multiple regulatory layers will be the key to ultimately cracking the cis-regulatory code.
Collapse
Affiliation(s)
- Seungsoo Kim
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Joanna Wysocka
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
| |
Collapse
|
31
|
Roles of Polycomb Complexes in the Reconstruction of 3D Genome Architecture during Preimplantation Embryonic Development. Genes (Basel) 2022; 13:genes13122382. [PMID: 36553649 PMCID: PMC9778514 DOI: 10.3390/genes13122382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 11/29/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
The appropriate deployment of developmental programs depends on complex genetic information encoded by genomic DNA sequences and their positioning and contacts in the three-dimensional (3D) space within the nucleus. Current studies using novel techniques including, but not limited to, Hi-C, ChIA-PET, and Hi-ChIP reveal that regulatory elements (Res), such as enhancers and promoters, may participate in the precise regulation of expression of tissue-specific genes important for both embryogenesis and organogenesis by recruiting Polycomb Group (PcG) complexes. PcG complexes usually poise the transcription of developmental genes by forming Polycomb bodies to compact poised enhancers and promoters marked by H3K27me3 in the 3D space. Additionally, recent studies have also uncovered their roles in transcriptional activation. To better understand the full complexities in the mechanisms of how PcG complexes regulate transcription and long-range 3D contacts of enhancers and promoters during developmental programs, we outline novel insights regarding PcG-associated dramatic changes in the 3D chromatin conformation in developmental programs of early embryos and naïve-ground-state transitions of pluripotent embryonic stem cells (ESCs), and highlight the distinct roles of unique and common subunits of canonical and non-canonical PcG complexes in shaping genome architectures and transcriptional programs.
Collapse
|
32
|
Guo Y, Wang GG. Modulation of the high-order chromatin structure by Polycomb complexes. Front Cell Dev Biol 2022; 10:1021658. [PMID: 36274840 PMCID: PMC9579376 DOI: 10.3389/fcell.2022.1021658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
The multi-subunit Polycomb Repressive Complex (PRC) 1 and 2 act, either independently or synergistically, to maintain and enforce a repressive state of the target chromatin, thereby regulating the processes of cell lineage specification and organismal development. In recent years, deep sequencing-based and imaging-based technologies, especially those tailored for mapping three-dimensional (3D) chromatin organization and structure, have allowed a better understanding of the PRC complex-mediated long-range chromatin contacts and DNA looping. In this review, we review current advances as for how Polycomb complexes function to modulate and help define the high-order chromatin structure and topology, highlighting the multi-faceted roles of Polycomb proteins in gene and genome regulation.
Collapse
Affiliation(s)
- Yiran Guo
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- *Correspondence: Yiran Guo, ; Gang Greg Wang,
| | - Gang Greg Wang
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, United States
- *Correspondence: Yiran Guo, ; Gang Greg Wang,
| |
Collapse
|
33
|
Hernández-Romero IA, Valdes VJ. De Novo Polycomb Recruitment and Repressive Domain Formation. EPIGENOMES 2022; 6:25. [PMID: 35997371 PMCID: PMC9397058 DOI: 10.3390/epigenomes6030025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/15/2022] [Accepted: 08/18/2022] [Indexed: 11/29/2022] Open
Abstract
Every cell of an organism shares the same genome; even so, each cellular lineage owns a different transcriptome and proteome. The Polycomb group proteins (PcG) are essential regulators of gene repression patterning during development and homeostasis. However, it is unknown how the repressive complexes, PRC1 and PRC2, identify their targets and elicit new Polycomb domains during cell differentiation. Classical recruitment models consider the pre-existence of repressive histone marks; still, de novo target binding overcomes the absence of both H3K27me3 and H2AK119ub. The CpG islands (CGIs), non-core proteins, and RNA molecules are involved in Polycomb recruitment. Nonetheless, it is unclear how de novo targets are identified depending on the physiological context and developmental stage and which are the leading players stabilizing Polycomb complexes at domain nucleation sites. Here, we examine the features of de novo sites and the accessory elements bridging its recruitment and discuss the first steps of Polycomb domain formation and transcriptional regulation, comprehended by the experimental reconstruction of the repressive domains through time-resolved genomic analyses in mammals.
Collapse
Affiliation(s)
| | - Victor Julian Valdes
- Department of Cell Biology and Development, Institute of Cellular Physiology (IFC), National Autonomous University of Mexico (UNAM), Mexico City 04510, Mexico
| |
Collapse
|
34
|
Polycomb-lamina antagonism partitions heterochromatin at the nuclear periphery. Nat Commun 2022; 13:4199. [PMID: 35859152 PMCID: PMC9300685 DOI: 10.1038/s41467-022-31857-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 07/06/2022] [Indexed: 11/08/2022] Open
Abstract
The genome can be divided into two spatially segregated compartments, A and B, which partition active and inactive chromatin states. While constitutive heterochromatin is predominantly located within the B compartment near the nuclear lamina, facultative heterochromatin marked by H3K27me3 spans both compartments. How epigenetic modifications, compartmentalization, and lamina association collectively maintain heterochromatin architecture remains unclear. Here we develop Lamina-Inducible Methylation and Hi-C (LIMe-Hi-C) to jointly measure chromosome conformation, DNA methylation, and lamina positioning. Through LIMe-Hi-C, we identify topologically distinct sub-compartments with high levels of H3K27me3 and differing degrees of lamina association. Inhibition of Polycomb repressive complex 2 (PRC2) reveals that H3K27me3 is essential for sub-compartment segregation. Unexpectedly, PRC2 inhibition promotes lamina association and constitutive heterochromatin spreading into H3K27me3-marked B sub-compartment regions. Consistent with this repositioning, genes originally marked with H3K27me3 in the B compartment, but not the A compartment, remain largely repressed, suggesting that constitutive heterochromatin spreading can compensate for H3K27me3 loss at a transcriptional level. These findings demonstrate that Polycomb sub-compartments and their antagonism with lamina association are fundamental features of genome structure. More broadly, by jointly measuring nuclear position and Hi-C contacts, our study demonstrates how compartmentalization and lamina association represent distinct but interdependent modes of heterochromatin regulation.
Collapse
|