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Gourisankar S, Krokhotin A, Wenderski W, Crabtree GR. Context-specific functions of chromatin remodellers in development and disease. Nat Rev Genet 2024; 25:340-361. [PMID: 38001317 DOI: 10.1038/s41576-023-00666-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2023] [Indexed: 11/26/2023]
Abstract
Chromatin remodellers were once thought to be highly redundant and nonspecific in their actions. However, recent human genetic studies demonstrate remarkable biological specificity and dosage sensitivity of the thirty-two adenosine triphosphate (ATP)-dependent chromatin remodellers encoded in the human genome. Mutations in remodellers produce many human developmental disorders and cancers, motivating efforts to investigate their distinct functions in biologically relevant settings. Exquisitely specific biological functions seem to be an emergent property in mammals, and in many cases are based on the combinatorial assembly of subunits and the generation of stable, composite surfaces. Critical interactions between remodelling complex subunits, the nucleosome and other transcriptional regulators are now being defined from structural and biochemical studies. In addition, in vivo analyses of remodellers at relevant genetic loci have provided minute-by-minute insights into their dynamics. These studies are proposing new models for the determinants of remodeller localization and function on chromatin.
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Affiliation(s)
- Sai Gourisankar
- Department of Pathology, Stanford University, Stanford, CA, USA
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Andrey Krokhotin
- Department of Pathology, Stanford University, Stanford, CA, USA
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
| | - Wendy Wenderski
- Department of Pathology, Stanford University, Stanford, CA, USA
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
| | - Gerald R Crabtree
- Department of Pathology, Stanford University, Stanford, CA, USA.
- Department of Developmental Biology, Stanford University, Stanford, CA, USA.
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2
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Valencia AM, Sankar A, van der Sluijs PJ, Satterstrom FK, Fu J, Talkowski ME, Vergano SAS, Santen GWE, Kadoch C. Landscape of mSWI/SNF chromatin remodeling complex perturbations in neurodevelopmental disorders. Nat Genet 2023; 55:1400-1412. [PMID: 37500730 PMCID: PMC10412456 DOI: 10.1038/s41588-023-01451-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 06/20/2023] [Indexed: 07/29/2023]
Abstract
DNA sequencing-based studies of neurodevelopmental disorders (NDDs) have identified a wide range of genetic determinants. However, a comprehensive analysis of these data, in aggregate, has not to date been performed. Here, we find that genes encoding the mammalian SWI/SNF (mSWI/SNF or BAF) family of ATP-dependent chromatin remodeling protein complexes harbor the greatest number of de novo missense and protein-truncating variants among nuclear protein complexes. Non-truncating NDD-associated protein variants predominantly disrupt the cBAF subcomplex and cluster in four key structural regions associated with high disease severity, including mSWI/SNF-nucleosome interfaces, the ATPase-core ARID-armadillo repeat (ARM) module insertion site, the Arp module and DNA-binding domains. Although over 70% of the residues perturbed in NDDs overlap with those mutated in cancer, ~60% of amino acid changes are NDD-specific. These findings provide a foundation to functionally group variants and link complex aberrancies to phenotypic severity, serving as a resource for the chromatin, clinical genetics and neurodevelopment communities.
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Affiliation(s)
- Alfredo M Valencia
- Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
- Chemical Biology Program, Harvard University, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Stanford Brain Organogenesis, Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
| | - Akshay Sankar
- Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | - F Kyle Satterstrom
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Massachusetts General Hospital, Boston, MA, USA
| | - Jack Fu
- Massachusetts General Hospital, Boston, MA, USA
| | - Michael E Talkowski
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Massachusetts General Hospital, Boston, MA, USA
| | - Samantha A Schrier Vergano
- Children's Hospital of the King's Daughters, Norfolk, Virginia, USA
- Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia, USA
| | - Gijs W E Santen
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Cigall Kadoch
- Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Chevy Chase, MD, USA.
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3
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Spatiotemporally controlled generation of NTPs for single-molecule studies. Nat Chem Biol 2022; 18:1144-1151. [PMID: 36131148 PMCID: PMC9512701 DOI: 10.1038/s41589-022-01100-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 06/29/2022] [Indexed: 12/22/2022]
Abstract
Many essential processes in the cell depend on proteins that use nucleoside triphosphates (NTPs). Methods that directly monitor the often-complex dynamics of these proteins at the single-molecule level have helped to uncover their mechanisms of action. However, the measurement throughput is typically limited for NTP-utilizing reactions, and the quantitative dissection of complex dynamics over multiple sequential turnovers remains challenging. Here we present a method for controlling NTP-driven reactions in single-molecule experiments via the local generation of NTPs (LAGOON) that markedly increases the measurement throughput and enables single-turnover observations. We demonstrate the effectiveness of LAGOON in single-molecule fluorescence and force spectroscopy assays by monitoring DNA unwinding, nucleosome sliding and RNA polymerase elongation. LAGOON can be readily integrated with many single-molecule techniques, and we anticipate that it will facilitate studies of a wide range of crucial NTP-driven processes. ![]()
A new method for controlling NTP-driven reactions in single-molecule experiments via the local generation of NTPs (LAGOON) markedly increases the measurement throughput and enables single-turnover observations.
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4
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Structure of human chromatin-remodelling PBAF complex bound to a nucleosome. Nature 2022; 605:166-171. [PMID: 35477757 DOI: 10.1038/s41586-022-04658-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 03/16/2022] [Indexed: 12/17/2022]
Abstract
DNA wraps around the histone octamer to form nucleosomes1, the repeating unit of chromatin, which create barriers for accessing genetic information. Snf2-like chromatin remodellers couple the energy of ATP binding and hydrolysis to reposition and recompose the nucleosome, and have vital roles in various chromatin-based transactions2,3. Here we report the cryo-electron microscopy structure of the 12-subunit human chromatin-remodelling polybromo-associated BRG1-associated factor (PBAF) complex bound to the nucleosome. The motor subunit SMARCA4 engages the nucleosome in the active conformation, which reveals clustering of multiple disease-associated mutations at the interfaces that are essential for chromatin-remodelling activity. SMARCA4 recognizes the H2A-H2B acidic pocket of the nucleosome through three arginine anchors of the Snf2 ATP coupling (SnAc) domain. PBAF shows notable functional modularity, and most of the auxiliary subunits are interwoven into three lobe-like submodules for nucleosome recognition. The PBAF-specific auxiliary subunit ARID2 acts as the structural core for assembly of the DNA-binding lobe, whereas PBRM1, PHF10 and BRD7 are collectively incorporated into the lobe for histone tail binding. Together, our findings provide mechanistic insights into nucleosome recognition by PBAF and a structural basis for understanding SMARCA4-related human diseases.
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5
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Zhao Y, Dong Y, Hong W, Jiang C, Yao K, Cheng C. Computational modeling of chromatin accessibility identified important epigenomic regulators. BMC Genomics 2022; 23:19. [PMID: 34996354 PMCID: PMC8742372 DOI: 10.1186/s12864-021-08234-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 12/03/2021] [Indexed: 11/28/2022] Open
Abstract
Chromatin accessibility is essential for transcriptional activation of genomic regions. It is well established that transcription factors (TFs) and histone modifications (HMs) play critical roles in chromatin accessibility regulation. However, there is a lack of studies that quantify these relationships. Here we constructed a two-layer model to predict chromatin accessibility by integrating DNA sequence, TF binding, and HM signals. By applying the model to two human cell lines (GM12878 and HepG2), we found that DNA sequences had limited power for accessibility prediction, while both TF binding and HM signals predicted chromatin accessibility with high accuracy. According to the HM model, HM features determined chromatin accessibility in a cell line shared manner, with the prediction power attributing to five core HM types. Results from the TF model indicated that chromatin accessibility was determined by a subset of informative TFs including both cell line-specific and generic TFs. The combined model of both TF and HM signals did not further improve the prediction accuracy, indicating that they provide redundant information in terms of chromatin accessibility prediction. The TFs and HM models can also distinguish the chromatin accessibility of proximal versus distal transcription start sites with high accuracy.
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Affiliation(s)
- Yanding Zhao
- Department of Medicine, Baylor College of Medicine, Room ICTR 100D, One Baylor Plaza, Baylor College of Medicine, Houston, TX, 77030, USA
- The Institute for Clinical and Translational Research, Baylor College of Medicine, Room ICTR 100D, One Baylor Plaza, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Yadong Dong
- Department of Medicine, Baylor College of Medicine, Room ICTR 100D, One Baylor Plaza, Baylor College of Medicine, Houston, TX, 77030, USA
- The Institute for Clinical and Translational Research, Baylor College of Medicine, Room ICTR 100D, One Baylor Plaza, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Wei Hong
- Department of Medicine, Baylor College of Medicine, Room ICTR 100D, One Baylor Plaza, Baylor College of Medicine, Houston, TX, 77030, USA
- The Institute for Clinical and Translational Research, Baylor College of Medicine, Room ICTR 100D, One Baylor Plaza, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Chongming Jiang
- Department of Medicine, Baylor College of Medicine, Room ICTR 100D, One Baylor Plaza, Baylor College of Medicine, Houston, TX, 77030, USA
- The Institute for Clinical and Translational Research, Baylor College of Medicine, Room ICTR 100D, One Baylor Plaza, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Kevin Yao
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Chao Cheng
- Department of Medicine, Baylor College of Medicine, Room ICTR 100D, One Baylor Plaza, Baylor College of Medicine, Houston, TX, 77030, USA.
- The Institute for Clinical and Translational Research, Baylor College of Medicine, Room ICTR 100D, One Baylor Plaza, Baylor College of Medicine, Houston, TX, 77030, USA.
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6
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Abstract
Epigenetic regulators are pivotal factors that influence and control T cell development. Recent findings continue to reveal additional elements of epigenetic modifications that play significant and crucial roles at different stages of T cell development. Through gaining a better understanding of the various epigenetic factors that influence the formation and survival of maturing T cells, new therapies can potentially be developed to combat diseases caused by dysregulated epigenetic chromatin modifications. In this review, we summarize the recent studies which shed light on the epigenetic regulation of T cell development especially at the critical stage of β-selection.
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Affiliation(s)
- Avik Dutta
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Harini Venkataganesh
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.,Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Paul E Love
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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Verma S, Singh A, Varshney A, Chandru RA, Acharya M, Rajput J, Sangwan VS, Tiwari AK, Bhowmick T, Tiwari A. Infectious Keratitis: An Update on Role of Epigenetics. Front Immunol 2021; 12:765890. [PMID: 34917084 PMCID: PMC8669721 DOI: 10.3389/fimmu.2021.765890] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/08/2021] [Indexed: 12/17/2022] Open
Abstract
Epigenetic mechanisms modulate gene expression and function without altering the base sequence of DNA. These reversible, heritable, and environment-influenced mechanisms generate various cell types during development and orchestrate the cellular responses to external stimuli by regulating the expression of genome. Also, the epigenetic modifications influence common pathological and physiological responses including inflammation, ischemia, neoplasia, aging and neurodegeneration etc. In recent past, the field of epigenetics has gained momentum and become an increasingly important area of biomedical research As far as eye is concerned, epigenetic mechanisms may play an important role in many complex diseases such as corneal dystrophy, cataract, glaucoma, diabetic retinopathy, ocular neoplasia, uveitis, and age-related macular degeneration. Focusing on the epigenetic mechanisms in ocular diseases may provide new understanding and insights into the pathogenesis of complex eye diseases and thus can aid in the development of novel treatments for these diseases. In the present review, we summarize the clinical perspective of infectious keratitis, role of epigenetics in infectious keratitis, therapeutic potential of epigenetic modifiers and the future perspective.
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Affiliation(s)
- Sudhir Verma
- Department of Zoology, Deen Dayal Upadhyaya College (University of Delhi), New Delhi, India
| | - Aastha Singh
- Department of Cornea and Uveitis, Dr. Shroff's Charity Eye Hospital, New Delhi, India
| | - Akhil Varshney
- Department of Cornea and Uveitis, Dr. Shroff's Charity Eye Hospital, New Delhi, India
| | - R Arun Chandru
- Pandorum Technologies Ltd., Bangalore Bioinnovation Centre, Bangalore, India
| | - Manisha Acharya
- Department of Cornea and Uveitis, Dr. Shroff's Charity Eye Hospital, New Delhi, India
| | - Jyoti Rajput
- Pandorum Technologies Ltd., Bangalore Bioinnovation Centre, Bangalore, India
| | | | - Amit K Tiwari
- Department of Pharmacology and Experimental Therapeutics, The University of Toledo, Toledo, OH, United States
| | - Tuhin Bhowmick
- Pandorum Technologies Ltd., Bangalore Bioinnovation Centre, Bangalore, India
| | - Anil Tiwari
- Department of Cornea and Uveitis, Dr. Shroff's Charity Eye Hospital, New Delhi, India
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8
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Shen CH, Allan J. MNase Digestion Protection Patterns of the Linker DNA in Chromatosomes. Cells 2021; 10:cells10092239. [PMID: 34571888 PMCID: PMC8469290 DOI: 10.3390/cells10092239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 11/16/2022] Open
Abstract
The compact nucleosomal structure limits DNA accessibility and regulates DNA-dependent cellular activities. Linker histones bind to nucleosomes and compact nucleosomal arrays into a higher-order chromatin structure. Recent developments in high throughput technologies and structural computational studies provide nucleosome positioning at a high resolution and contribute to the information of linker histone location within a chromatosome. However, the precise linker histone location within the chromatin fibre remains unclear. Using monomer extension, we mapped core particle and chromatosomal positions over a core histone-reconstituted, 1.5 kb stretch of DNA from the chicken adult β-globin gene, after titration with linker histones and linker histone globular domains. Our results show that, although linker histone globular domains and linker histones display a wide variation in their binding affinity for different positioned nucleosomes, they do not alter nucleosome positions or generate new nucleosome positions. Furthermore, the extra ~20 bp of DNA protected in a chromatosome is usually symmetrically distributed at each end of the core particle, suggesting linker histones or linker histone globular domains are located close to the nucleosomal dyad axis.
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Affiliation(s)
- Chang-Hui Shen
- Biology Department, College of Staten Island, City University of New York, 2800 Victory Boulevard, Staten Island, NY 10314, USA
- Biochemistry and Biology Ph.D. Program, Graduate Center, City University of New York, New York, NY 10016, USA
- Institute for Macromolecular Assemblies, City University of New York, New York, NY 10031, USA
- Correspondence: ; Tel.: +1-718-982-3998; Fax: +1-718-982-3852
| | - James Allan
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK;
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9
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The BAF chromatin remodeling complexes: structure, function, and synthetic lethalities. Biochem Soc Trans 2021; 49:1489-1503. [PMID: 34431497 DOI: 10.1042/bst20190960] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/20/2021] [Accepted: 07/23/2021] [Indexed: 02/08/2023]
Abstract
BAF complexes are multi-subunit chromatin remodelers, which have a fundamental role in genomic regulation. Large-scale sequencing efforts have revealed frequent BAF complex mutations in many human diseases, particularly in cancer and neurological disorders. These findings not only underscore the importance of the BAF chromatin remodelers in cellular physiological processes, but urge a more detailed understanding of their structure and molecular action to enable the development of targeted therapeutic approaches for diseases with BAF complex alterations. Here, we review recent progress in understanding the composition, assembly, structure, and function of BAF complexes, and the consequences of their disease-associated mutations. Furthermore, we highlight intra-complex subunit dependencies and synthetic lethal interactions, which have emerged as promising treatment modalities for BAF-related diseases.
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10
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Lin X, Yuan C, Zhu B, Yuan T, Li X, Yuan S, Cui S, Zhao H. LFR Physically and Genetically Interacts With SWI/SNF Component SWI3B to Regulate Leaf Blade Development in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2021; 12:717649. [PMID: 34456957 PMCID: PMC8385146 DOI: 10.3389/fpls.2021.717649] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/14/2021] [Indexed: 05/26/2023]
Abstract
Leaves start to develop at the peripheral zone of the shoot apical meristem. Thereafter, symmetric and flattened leaf laminae are formed. These events are simultaneously regulated by auxin, transcription factors, and epigenetic regulatory factors. However, the relationships among these factors are not well known. In this study, we conducted protein-protein interaction assays to show that our previously reported Leaf and Flower Related (LFR) physically interacted with SWI3B, a component of the ATP-dependent chromatin remodeling SWI/SNF complex in Arabidopsis. The results of truncated analysis and transgenic complementation showed that the N-terminal domain (25-60 amino acids) of LFR was necessary for its interaction with SWI3B and was crucial for LFR functions in Arabidopsis leaf development. Genetic results showed that the artificial microRNA knockdown lines of SWI3B (SWI3B-amic) had a similar upward-curling leaf phenotype with that of LFR loss-of-function mutants. ChIP-qPCR assay was conducted to show that LFR and SWI3B co-targeted the promoters of YABBY1/FILAMENTOUS FLOWER (YAB1/FIL) and IAA carboxyl methyltransferase 1 (IAMT1), which were misexpressed in lfr and SWI3B-amic mutants. In addition, the association between LFR and the FIL and IAMT1 loci was partly hampered by the knockdown of SWI3B. These data suggest that LFR interacts with the chromatin-remodeling complex component, SWI3B, and influences the transcriptional expression of the important transcription factor, FIL, and the auxin metabolism enzyme, IAMT1, in flattened leaf lamina development.
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Affiliation(s)
- Xiaowei Lin
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
- School of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Can Yuan
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Bonan Zhu
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Tingting Yuan
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Xiaorong Li
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Shan Yuan
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Sujuan Cui
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Hongtao Zhao
- Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, College of Life Sciences, Hebei Normal University, Shijiazhuang, China
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11
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Tilly BC, Chalkley GE, van der Knaap JA, Moshkin YM, Kan TW, Dekkers DH, Demmers JA, Verrijzer CP. In vivo analysis reveals that ATP-hydrolysis couples remodeling to SWI/SNF release from chromatin. eLife 2021; 10:69424. [PMID: 34313222 PMCID: PMC8352592 DOI: 10.7554/elife.69424] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/26/2021] [Indexed: 12/23/2022] Open
Abstract
ATP-dependent chromatin remodelers control the accessibility of genomic DNA through nucleosome mobilization. However, the dynamics of genome exploration by remodelers, and the role of ATP hydrolysis in this process remain unclear. We used live-cell imaging of Drosophila polytene nuclei to monitor Brahma (BRM) remodeler interactions with its chromosomal targets. In parallel, we measured local chromatin condensation and its effect on BRM association. Surprisingly, only a small portion of BRM is bound to chromatin at any given time. BRM binds decondensed chromatin but is excluded from condensed chromatin, limiting its genomic search space. BRM-chromatin interactions are highly dynamic, whereas histone-exchange is limited and much slower. Intriguingly, loss of ATP hydrolysis enhanced chromatin retention and clustering of BRM, which was associated with reduced histone turnover. Thus, ATP hydrolysis couples nucleosome remodeling to remodeler release, driving a continuous transient probing of the genome.
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Affiliation(s)
- Ben C Tilly
- Department of Biochemistry, Rotterdam, Netherlands
| | | | | | | | | | - Dick Hw Dekkers
- Department of Biochemistry, Rotterdam, Netherlands.,Proteomics Center, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Jeroen Aa Demmers
- Department of Biochemistry, Rotterdam, Netherlands.,Proteomics Center, Erasmus University Medical Center, Rotterdam, Netherlands
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12
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Ni K, Muegge K. LSH catalyzes ATP-driven exchange of histone variants macroH2A1 and macroH2A2. Nucleic Acids Res 2021; 49:8024-8036. [PMID: 34223906 DOI: 10.1093/nar/gkab588] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 06/07/2021] [Accepted: 06/24/2021] [Indexed: 11/12/2022] Open
Abstract
LSH, a homologue of the ISWI/SNF2 family of chromatin remodelers, is required in vivo for deposition of the histone variants macroH2A1 and macroH2A2 at specific genomic locations. However, it remains unknown whether LSH is directly involved in this process or promotes other factors. Here we show that recombinant LSH interacts in vitro with macroH2A1-H2B and macroH2A2-H2B dimers, but not with H2A.Z-H2B dimers. Moreover, LSH catalyzes the transfer of macroH2A into mono-nucleosomes reconstituted with canonical core histones in an ATP dependent manner. LSH requires the ATP binding site and the replacement process is unidirectional leading to heterotypic and homotypic nucleosomes. Both variants macroH2A1 and macroH2A2 are equally well incorporated into the nucleosome. The histone exchange reaction is specific for histone variant macroH2A, since LSH is not capable to incorporate H2A.Z. These findings define a previously unknown role for LSH in chromatin remodeling and identify a novel molecular mechanism for deposition of the histone variant macroH2A.
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Affiliation(s)
- Kai Ni
- Epigenetics Section, Mouse Cancer Genetics Program, National Cancer Institute, Frederick, MD 21702, USA
| | - Kathrin Muegge
- Epigenetics Section, Frederick National Laboratory for Cancer Research in the Mouse Cancer Genetics Program, National Cancer Institute, Frederick, MD 21702, USA
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