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Lu W, Liu Y, Li J, Huang S, Wen Z, Su C, Lu Z, Mo Z, Yu Z. Single-cell assay for transposase-accessible chromatin sequencing of human clear cell renal cell carcinoma. Sci Data 2025; 12:334. [PMID: 40000710 PMCID: PMC11861977 DOI: 10.1038/s41597-025-04666-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2024] [Accepted: 02/18/2025] [Indexed: 02/27/2025] Open
Abstract
Regulating the occurrence and progression of tumor cells at the epigenetic level is a new insight of clear cell renal cell carcinoma (ccRCC). Chromatin accessibility is an important pathway of epigenetic regulation, which may explain the mystery of tumor occurrence. Assay for transposase-accessible chromatin sequencing (ATAC-seq) provides insight into the epigenetic regulatory features of ccRCC, especially at the single-cell level. In this study, we performed scATAC-seq of 3 ccRCC samples and captured a total of 18,703 high-quality cell nuclei and 104,818 unique peaks. Our protocol for nuclear extraction was reliable and stable, which can be used to deal with fresh and frozen single-cell suspensions. We presented basic methods for scATAC-seq data analysis, such as cell clustering, gene activity scoring, cell subtype specific peaks, transcription factors, motif and motif footprinting analysis. Taken together, our data indicated the valuable epigenetic features of ccRCC, which will provide more references for the study of ccRCC.
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Affiliation(s)
- Wenhao Lu
- Department of Urology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
- Center for Genomic and Personalized Medicine, Guangxi key Laboratory for Genomic and Personalized Medicine, Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, 530021, Guangxi, China
- Institute of Urology and Nephrology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Yixuan Liu
- Department of Urology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
- Center for Genomic and Personalized Medicine, Guangxi key Laboratory for Genomic and Personalized Medicine, Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, 530021, Guangxi, China
- Institute of Urology and Nephrology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Jiaping Li
- Guangxi Key Laboratory of Precision Medicine in Cardio-Cerebrovascular Diseases Control and Prevention, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Shengzhu Huang
- Center for Genomic and Personalized Medicine, Guangxi key Laboratory for Genomic and Personalized Medicine, Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, 530021, Guangxi, China
- Institute of Urology and Nephrology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Zheng Wen
- Center for Genomic and Personalized Medicine, Guangxi key Laboratory for Genomic and Personalized Medicine, Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, 530021, Guangxi, China
- Institute of Urology and Nephrology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Cheng Su
- Center for Genomic and Personalized Medicine, Guangxi key Laboratory for Genomic and Personalized Medicine, Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, 530021, Guangxi, China
- Institute of Urology and Nephrology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Zheng Lu
- Department of Urology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China.
| | - Zengnan Mo
- Department of Urology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China.
- Center for Genomic and Personalized Medicine, Guangxi key Laboratory for Genomic and Personalized Medicine, Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, 530021, Guangxi, China.
- Institute of Urology and Nephrology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China.
| | - Zhenyuan Yu
- Department of Urology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China.
- Center for Genomic and Personalized Medicine, Guangxi key Laboratory for Genomic and Personalized Medicine, Guangxi Collaborative Innovation Center for Genomic and Personalized Medicine, Guangxi Medical University, Nanning, 530021, Guangxi, China.
- Institute of Urology and Nephrology, The First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China.
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2
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Yang J, Yen K, Mahony S. Size-based expectation maximization for characterizing nucleosome positions and subtypes. Genome Res 2024; 34:1334-1343. [PMID: 38886069 PMCID: PMC11529872 DOI: 10.1101/gr.279138.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 05/13/2024] [Indexed: 06/20/2024]
Abstract
Genome-wide nucleosome profiles are predominantly characterized using MNase-seq, which involves extensive MNase digestion and size selection to enrich for mononucleosome-sized fragments. Most available MNase-seq analysis packages assume that nucleosomes uniformly protect 147 bp DNA fragments. However, some nucleosomes with atypical histone or chemical compositions protect shorter lengths of DNA. The rigid assumptions imposed by current nucleosome analysis packages potentially prevent investigators from understanding the regulatory roles played by atypical nucleosomes. To enable the characterization of different nucleosome types from MNase-seq data, we introduce the size-based expectation maximization (SEM) nucleosome-calling package. SEM employs a hierarchical Gaussian mixture model to estimate nucleosome positions and subtypes. Nucleosome subtypes are automatically identified based on the distribution of protected DNA fragments. Benchmark analysis indicates that SEM is on par with existing packages in terms of standard nucleosome-calling accuracy metrics, while uniquely providing the ability to characterize nucleosome subtype identities. Applying SEM to a low-dose MNase-H2B-ChIP-seq data set from mouse embryonic stem cells, we identified three nucleosome types: short-fragment nucleosomes, canonical nucleosomes, and di-nucleosomes. Short-fragment nucleosomes can be divided further into two subtypes based on their chromatin accessibility. Short-fragment nucleosomes in accessible regions exhibit high MNase sensitivity and are enriched at transcription start sites (TSSs) and CTCF peaks, similar to previously reported "fragile nucleosomes." These SEM-defined accessible short-fragment nucleosomes are found not just in promoters but also in distal regulatory regions. Additional analyses reveal their colocalization with the chromatin remodelers CHD6, CHD8, and EP400. In summary, SEM provides an effective platform for exploration of nonstandard nucleosome subtypes.
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Affiliation(s)
- Jianyu Yang
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Kuangyu Yen
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China;
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Shaun Mahony
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA;
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3
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Wernig-Zorc S, Kugler F, Schmutterer L, Räß P, Hausmann C, Holzinger S, Längst G, Schwartz U. nucMACC: An MNase-seq pipeline to identify structurally altered nucleosomes in the genome. SCIENCE ADVANCES 2024; 10:eadm9740. [PMID: 38959309 PMCID: PMC11221511 DOI: 10.1126/sciadv.adm9740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 05/30/2024] [Indexed: 07/05/2024]
Abstract
Micrococcal nuclease sequencing is the state-of-the-art method for determining chromatin structure and nucleosome positioning. Data analysis is complex due to the AT-dependent sequence bias of the endonuclease and the requirement for high sequencing depth. Here, we present the nucleosome-based MNase accessibility (nucMACC) pipeline unveiling the regulatory chromatin landscape by measuring nucleosome accessibility and stability. The nucMACC pipeline represents a systematic and genome-wide approach for detecting unstable ("fragile") nucleosomes. We have characterized the regulatory nucleosome landscape in Drosophila melanogaster, Saccharomyces cerevisiae, and mammals. Two functionally distinct sets of promoters were characterized, one associated with an unstable nucleosome and the other being nucleosome depleted. We show that unstable nucleosomes present intermediate states of nucleosome remodeling, preparing inducible genes for transcriptional activation in response to stimuli or stress. The presence of unstable nucleosomes correlates with RNA polymerase II proximal pausing. The nucMACC pipeline offers unparalleled precision and depth in nucleosome research and is a valuable tool for future nucleosome studies.
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Affiliation(s)
- Sara Wernig-Zorc
- Regensburg Center for Biochemistry (RCB), University of Regensburg, Regensburg, Germany
| | - Fabian Kugler
- Regensburg Center for Biochemistry (RCB), University of Regensburg, Regensburg, Germany
| | - Leo Schmutterer
- NGS Analysis Center Biology and Pre-clinical Medicine, University of Regensburg, Regensburg, Germany
| | - Patrick Räß
- NGS Analysis Center Biology and Pre-clinical Medicine, University of Regensburg, Regensburg, Germany
| | - Clemens Hausmann
- NGS Analysis Center Biology and Pre-clinical Medicine, University of Regensburg, Regensburg, Germany
| | - Simon Holzinger
- Regensburg Center for Biochemistry (RCB), University of Regensburg, Regensburg, Germany
| | - Gernot Längst
- Regensburg Center for Biochemistry (RCB), University of Regensburg, Regensburg, Germany
| | - Uwe Schwartz
- NGS Analysis Center Biology and Pre-clinical Medicine, University of Regensburg, Regensburg, Germany
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4
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Brandani GB, Gu C, Gopi S, Takada S. Multiscale Bayesian simulations reveal functional chromatin condensation of gene loci. PNAS NEXUS 2024; 3:pgae226. [PMID: 38881841 PMCID: PMC11179106 DOI: 10.1093/pnasnexus/pgae226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 05/30/2024] [Indexed: 06/18/2024]
Abstract
Chromatin, the complex assembly of DNA and associated proteins, plays a pivotal role in orchestrating various genomic functions. To aid our understanding of the principles underlying chromatin organization, we introduce Hi-C metainference, a Bayesian approach that integrates Hi-C contact frequencies into multiscale prior models of chromatin. This approach combines both bottom-up (the physics-based prior) and top-down (the data-driven posterior) strategies to characterize the 3D organization of a target genomic locus. We first demonstrate the capability of this method to accurately reconstruct the structural ensemble and the dynamics of a system from contact information. We then apply the approach to investigate the Sox2, Pou5f1, and Nanog loci of mouse embryonic stem cells using a bottom-up chromatin model at 1 kb resolution. We observe that the studied loci are conformationally heterogeneous and organized as crumpled globules, favoring contacts between distant enhancers and promoters. Using nucleosome-resolution simulations, we then reveal how the Nanog gene is functionally organized across the multiple scales of chromatin. At the local level, we identify diverse tetranucleosome folding motifs with a characteristic distribution along the genome, predominantly open at cis-regulatory elements and compact in between. At the larger scale, we find that enhancer-promoter contacts are driven by the transient condensation of chromatin into compact domains stabilized by extensive internucleosome interactions. Overall, this work highlights the condensed, but dynamic nature of chromatin in vivo, contributing to a deeper understanding of gene structure-function relationships.
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Affiliation(s)
- Giovanni B Brandani
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Chenyang Gu
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Soundhararajan Gopi
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Shoji Takada
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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5
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Yang J, Yen K, Mahony S. SEM: sized-based expectation maximization for characterizing nucleosome positions and subtypes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.17.562727. [PMID: 37904910 PMCID: PMC10614873 DOI: 10.1101/2023.10.17.562727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
Genome-wide nucleosome profiles are predominantly characterized using MNase-seq, which involves extensive MNase digestion and size selection to enrich for mono-nucleosome-sized fragments. Most available MNase-seq analysis packages assume that nucleosomes uniformly protect 147bp DNA fragments. However, some nucleosomes with atypical histone or chemical compositions protect shorter lengths of DNA. The rigid assumptions imposed by current nucleosome analysis packages ignore variation in nucleosome lengths, potentially blinding investigators to regulatory roles played by atypical nucleosomes. To enable the characterization of different nucleosome types from MNase-seq data, we introduce the Size-based Expectation Maximization (SEM) nucleosome calling package. SEM employs a hierarchical Gaussian mixture model to estimate the positions and subtype identity of nucleosomes from MNase-seq fragments. Nucleosome subtypes are automatically identified based on the distribution of protected DNA fragment lengths at nucleosome positions. Benchmark analysis indicates that SEM is on par with existing packages in terms of standard nucleosome-calling accuracy metrics, while uniquely providing the ability to characterize nucleosome subtype identities. Using SEM on a low-dose MNase H2B MNase-ChIP-seq dataset from mouse embryonic stem cells, we identified three nucleosome types: short-fragment nucleosomes, canonical nucleosomes, and di-nucleosomes. The short-fragment nucleosomes can be divided further into two subtypes based on their chromatin accessibility. Interestingly, the subset of short-fragment nucleosomes in accessible regions exhibit high MNase sensitivity and display distribution patterns around transcription start sites (TSSs) and CTCF peaks, similar to the previously reported "fragile nucleosomes". These SEM-defined accessible short-fragment nucleosomes are found not just in promoters, but also in enhancers and other regulatory regions. Additional investigations reveal their co-localization with the chromatin remodelers Chd6, Chd8, and Ep400. In summary, SEM provides an effective platform for distinguishing various nucleosome subtypes, paving the way for future exploration of non-standard nucleosomes.
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Affiliation(s)
- Jianyu Yang
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Kuangyu Yen
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin 300020, China
- Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Shaun Mahony
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
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Zhang A, Li X, Zhao H, Jiang J, Zhang W. Genome-Wide Identification of Open Chromatin in Plants Using MH-Seq. Methods Mol Biol 2023; 2594:29-43. [PMID: 36264486 DOI: 10.1007/978-1-0716-2815-7_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Functional cis-regulatory elements (CREs) act as precise transcriptional switches for fine-tuning gene transcription. Identification of CREs is critical for understanding regulatory mechanisms of gene expression associated with various biological processes in eukaryotes. It is well known that CREs reside in open chromatin that exhibits hypersensitivity to enzyme cleavage and physical shearing. Currently, high-throughput methodologies, such as DNase-seq, ATAC-seq, and FAIRE-seq, have been widely applied in mapping open chromatin in various eukaryotic genomes. More recently, differential MNase (micrococcal nuclease) treatment has been successfully employed to map open chromatin in addition to profiling nucleosome landscape in both mammalian and plant species. We have developed a MNase hypersensitivity sequencing (MH-seq) technique in plants. The MH-seq procedure includes plant nuclei fixation and purification, differential treatments of purified nuclei with MNase, specific recovery of MNase-trimmed small DNA fragments within 20~100 bp in length, and MH-seq library construction followed by Illumina sequencing and data analysis. MH-seq has been successfully applied for global identification of open chromatin in both Arabidopsis thaliana and maize. It has been proven to be an attractive alternative for profiling open chromatin. Thus, MH-seq is expected to be valuable in probing chromatin accessibility on a genome-wide scale for other plants with sequenced genomes. Moreover, MHS data allow to implement footprinting assays to unveil binding sites of transcription factors.
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Affiliation(s)
- Aicen Zhang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, JCIC-MCP, CIC-MCP, Nanjing Agricultural University, Nanjing, Jiangsu, P. R. China
| | - Xinxu Li
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, JCIC-MCP, CIC-MCP, Nanjing Agricultural University, Nanjing, Jiangsu, P. R. China
| | - Hainan Zhao
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - Jiming Jiang
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
- Department of Horticulture, Michigan State University, East Lansing, MI, USA
| | - Wenli Zhang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, JCIC-MCP, CIC-MCP, Nanjing Agricultural University, Nanjing, Jiangsu, P. R. China.
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7
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A giant virus genome is densely packaged by stable nucleosomes within virions. Mol Cell 2022; 82:4458-4470.e5. [PMID: 36370708 DOI: 10.1016/j.molcel.2022.10.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 09/09/2022] [Accepted: 10/19/2022] [Indexed: 11/13/2022]
Abstract
The two doublet histones of Marseillevirus are distantly related to the four eukaryotic core histones and wrap 121 base pairs of DNA to form remarkably similar nucleosomes. By permeabilizing Marseillevirus virions and performing genome-wide nuclease digestion, chemical cleavage, and mass spectrometry assays, we find that the higher-order organization of Marseillevirus chromatin fundamentally differs from that of eukaryotes. Marseillevirus nucleosomes fully protect DNA within virions as closely abutted 121-bp DNA-wrapped cores without linker DNA or phasing along genes. Likewise, we observed that nucleosomes reconstituted onto multi-copy tandem repeats of a nucleosome-positioning sequence are tightly packed. Dense promiscuous packing of fully wrapped nucleosomes rather than "beads on a string" with genic punctuation represents a distinct mode of DNA packaging by histones. We suggest that doublet histones have evolved for viral genome protection and may resemble an early stage of histone differentiation leading to the eukaryotic octameric nucleosome.
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8
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Mansisidor AR, Risca VI. Chromatin accessibility: methods, mechanisms, and biological insights. Nucleus 2022; 13:236-276. [PMID: 36404679 PMCID: PMC9683059 DOI: 10.1080/19491034.2022.2143106] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/23/2022] [Accepted: 10/30/2022] [Indexed: 11/22/2022] Open
Abstract
Access to DNA is a prerequisite to the execution of essential cellular processes that include transcription, replication, chromosomal segregation, and DNA repair. How the proteins that regulate these processes function in the context of chromatin and its dynamic architectures is an intensive field of study. Over the past decade, genome-wide assays and new imaging approaches have enabled a greater understanding of how access to the genome is regulated by nucleosomes and associated proteins. Additional mechanisms that may control DNA accessibility in vivo include chromatin compaction and phase separation - processes that are beginning to be understood. Here, we review the ongoing development of accessibility measurements, we summarize the different molecular and structural mechanisms that shape the accessibility landscape, and we detail the many important biological functions that are linked to chromatin accessibility.
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Affiliation(s)
- Andrés R. Mansisidor
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
| | - Viviana I. Risca
- Laboratory of Genome Architecture and Dynamics, The Rockefeller University, New York, NY
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9
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Henikoff S, Ahmad K. In situ tools for chromatin structural epigenomics. Protein Sci 2022; 31:e4458. [PMID: 36170035 PMCID: PMC9601787 DOI: 10.1002/pro.4458] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/19/2022] [Accepted: 09/22/2022] [Indexed: 12/14/2022]
Abstract
Technological progress over the past 15 years has fueled an explosion in genome-wide chromatin profiling tools that take advantage of low-cost short-read sequencing technologies to map particular chromatin features. Here, we survey the recent development of epigenomic tools that provide precise positions of chromatin proteins genome-wide in intact cells or nuclei. Some profiling tools are based on tethering Micrococcal Nuclease to chromatin proteins of interest in situ, whereas others similarly tether Tn5 transposase to integrate DNA sequencing adapters (tagmentation) and so eliminate the need for library preparation. These in situ cleavage and tagmentation tools have gained in popularity over the past few years, with many protocol enhancements and adaptations for single-cell and spatial chromatin profiling. The application of experimental and computational tools to address problems in gene regulation, eukaryotic development, and human disease are helping to define the emerging field of chromatin structural epigenomics.
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Affiliation(s)
- Steven Henikoff
- Fred Hutchinson Cancer CenterSeattleWashingtonUSA
- Howard Hughes Medical InstituteChevy ChaseMarylandUSA
| | - Kami Ahmad
- Fred Hutchinson Cancer CenterSeattleWashingtonUSA
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10
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Talbert PB, Armache KJ, Henikoff S. Viral histones: pickpocket's prize or primordial progenitor? Epigenetics Chromatin 2022; 15:21. [PMID: 35624484 PMCID: PMC9145170 DOI: 10.1186/s13072-022-00454-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 04/19/2022] [Indexed: 12/12/2022] Open
Abstract
The common histones H2A, H2B, H3, and H4 are the characteristic components of eukaryotic nucleosomes, which function to wrap DNA and compact the genome as well as to regulate access to DNA for transcription and replication in all eukaryotes. In the past two decades, histones have also been found to be encoded in some DNA viruses, where their functions and properties are largely unknown, though recently histones from two related viruses have been shown to form nucleosome-like structures in vitro. Viral histones can be highly similar to eukaryotic histones in primary sequence, suggesting they have been recently picked up from eukaryotic hosts, or they can be radically divergent in primary sequence and may occur as conjoined histone doublets, triplets, or quadruplets, suggesting ancient origins prior to the divergence of modern eukaryotes. Here, we review what is known of viral histones and discuss their possible origins and functions. We consider how the viral life cycle may affect their properties and histories, and reflect on the possible roles of viruses in the origin of the nucleus of modern eukaryotic cells.
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Affiliation(s)
- Paul B Talbert
- Howard Hughes Medical Institute and Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA, 98109, USA
| | - Karim-Jean Armache
- Skirball Institute of Biomolecular Medicine, Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, 550 First Ave, New York, NY, 10016, USA
| | - Steven Henikoff
- Howard Hughes Medical Institute and Fred Hutchinson Cancer Center, 1100 Fairview Ave N, Seattle, WA, 98109, USA.
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11
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Mapping nucleosome and chromatin architectures: A survey of computational methods. Comput Struct Biotechnol J 2022; 20:3955-3962. [PMID: 35950186 PMCID: PMC9340519 DOI: 10.1016/j.csbj.2022.07.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 07/22/2022] [Accepted: 07/22/2022] [Indexed: 11/21/2022] Open
Abstract
With ever-growing genomic sequencing data, the data variabilities and the underlying biases of the sequencing technologies pose significant computational challenges ranging from the need for accurately detecting the nucleosome positioning or chromatin interaction to the need for developing normalization methods to eliminate systematic biases. This review mainly surveys the computational methods for mapping the higher-resolution nucleosome and higher-order chromatin architectures. While a detailed discussion of the underlying algorithms is beyond the scope of our survey, we have discussed the methods and tools that can detect the nucleosomes in the genome, then demonstrated the computational methods for identifying 3D chromatin domains and interactions. We further illustrated computational approaches for integrating multi-omics data with Hi-C data and the advance of single-cell (sc)Hi-C data analysis. Our survey provides a comprehensive and valuable resource for biomedical scientists interested in studying nucleosome organization and chromatin structures as well as for computational scientists who are interested in improving upon them.
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12
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Xu W, Wen Y, Liang Y, Xu Q, Wang X, Jin W, Chen X. A plate-based single-cell ATAC-seq workflow for fast and robust profiling of chromatin accessibility. Nat Protoc 2021; 16:4084-4107. [PMID: 34282334 DOI: 10.1038/s41596-021-00583-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 06/04/2021] [Indexed: 02/06/2023]
Abstract
Profiling chromatin accessibility at the single-cell level provides critical information about cell type composition and cell-to-cell variation within a complex tissue. Emerging techniques for the interrogation of chromatin accessibility in individual cells allow investigation of the fundamental mechanisms that lead to the variability of different cells. This protocol describes a fast and robust method for single-cell chromatin accessibility profiling based on the assay for transposase-accessible chromatin using sequencing (ATAC-seq). The method combines up-front bulk Tn5 tagging of chromatin with flow cytometry to isolate single nuclei or cells. Reagents required to generate sequencing libraries are added to the same well in the plate where cells are sorted. The protocol described here generates data of high complexity and excellent signal-to-noise ratio and can be combined with index sorting for in-depth characterization of cell types. The whole experimental procedure can be finished within 1 or 2 d with a throughput of hundreds to thousands of nuclei, and the data can be processed by the provided computational pipeline. The execution of the protocol only requires basic techniques and equipment in a molecular biology laboratory with flow cytometry support.
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Affiliation(s)
- Wei Xu
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Yi Wen
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Yingying Liang
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Qiushi Xu
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Xuefei Wang
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Wenfei Jin
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Xi Chen
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.
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13
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Wilson SL, Wallingford M. Epigenetic regulation of reproduction in human and in animal models. Mol Hum Reprod 2021; 27:6329199. [PMID: 34318322 DOI: 10.1093/molehr/gaab041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/07/2021] [Indexed: 12/24/2022] Open
Affiliation(s)
- Samantha L Wilson
- Princess Margaret Cancer Centre, University Health Network, Toronto Medical Discovery Tower, Toronto, ON, Canada
| | - Mary Wallingford
- Mother Infant Research Institute, Tufts Medical Center, Boston, MA, USA.,Division of Obstetrics and Gynecology, Tufts University School of Medicine, Boston, MA, USA
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14
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Chanou A, Hamperl S. Single-Molecule Techniques to Study Chromatin. Front Cell Dev Biol 2021; 9:699771. [PMID: 34291054 PMCID: PMC8287188 DOI: 10.3389/fcell.2021.699771] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 05/26/2021] [Indexed: 12/14/2022] Open
Abstract
Besides the basic organization in nucleosome core particles (NCPs), eukaryotic chromatin is further packed through interactions with numerous protein complexes including transcription factors, chromatin remodeling and modifying enzymes. This nucleoprotein complex provides the template for many important biological processes, such as DNA replication, transcription, and DNA repair. Thus, to understand the molecular basis of these DNA transactions, it is critical to define individual changes of the chromatin structure at precise genomic regions where these machineries assemble and drive biological reactions. Single-molecule approaches provide the only possible solution to overcome the heterogenous nature of chromatin and monitor the behavior of individual chromatin transactions in real-time. In this review, we will give an overview of currently available single-molecule methods to obtain mechanistic insights into nucleosome positioning, histone modifications and DNA replication and transcription analysis-previously unattainable with population-based assays.
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Affiliation(s)
| | - Stephan Hamperl
- Chromosome Dynamics and Genome Stability, Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
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15
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Clapier CR. Sophisticated Conversations between Chromatin and Chromatin Remodelers, and Dissonances in Cancer. Int J Mol Sci 2021; 22:5578. [PMID: 34070411 PMCID: PMC8197500 DOI: 10.3390/ijms22115578] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/18/2021] [Accepted: 05/18/2021] [Indexed: 01/13/2023] Open
Abstract
The establishment and maintenance of genome packaging into chromatin contribute to define specific cellular identity and function. Dynamic regulation of chromatin organization and nucleosome positioning are critical to all DNA transactions-in particular, the regulation of gene expression-and involve the cooperative action of sequence-specific DNA-binding factors, histone modifying enzymes, and remodelers. Remodelers are molecular machines that generate various chromatin landscapes, adjust nucleosome positioning, and alter DNA accessibility by using ATP binding and hydrolysis to perform DNA translocation, which is highly regulated through sophisticated structural and functional conversations with nucleosomes. In this review, I first present the functional and structural diversity of remodelers, while emphasizing the basic mechanism of DNA translocation, the common regulatory aspects, and the hand-in-hand progressive increase in complexity of the regulatory conversations between remodelers and nucleosomes that accompanies the increase in challenges of remodeling processes. Next, I examine how, through nucleosome positioning, remodelers guide the regulation of gene expression. Finally, I explore various aspects of how alterations/mutations in remodelers introduce dissonance into the conversations between remodelers and nucleosomes, modify chromatin organization, and contribute to oncogenesis.
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Affiliation(s)
- Cedric R Clapier
- Department of Oncological Sciences & Howard Hughes Medical Institute, Huntsman Cancer Institute, University of Utah School of Medicine, 2000 Circle of Hope, Salt Lake City, UT 84112, USA
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16
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Minnoye L, Marinov GK, Krausgruber T, Pan L, Marand AP, Secchia S, Greenleaf WJ, Furlong EEM, Zhao K, Schmitz RJ, Bock C, Aerts S. Chromatin accessibility profiling methods. NATURE REVIEWS. METHODS PRIMERS 2021; 1:10. [PMID: 38410680 PMCID: PMC10895463 DOI: 10.1038/s43586-020-00008-9] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/01/2020] [Indexed: 02/06/2023]
Abstract
Chromatin accessibility, or the physical access to chromatinized DNA, is a widely studied characteristic of the eukaryotic genome. As active regulatory DNA elements are generally 'accessible', the genome-wide profiling of chromatin accessibility can be used to identify candidate regulatory genomic regions in a tissue or cell type. Multiple biochemical methods have been developed to profile chromatin accessibility, both in bulk and at the single-cell level. Depending on the method, enzymatic cleavage, transposition or DNA methyltransferases are used, followed by high-throughput sequencing, providing a view of genome-wide chromatin accessibility. In this Primer, we discuss these biochemical methods, as well as bioinformatics tools for analysing and interpreting the generated data, and insights into the key regulators underlying developmental, evolutionary and disease processes. We outline standards for data quality, reproducibility and deposition used by the genomics community. Although chromatin accessibility profiling is invaluable to study gene regulation, alone it provides only a partial view of this complex process. Orthogonal assays facilitate the interpretation of accessible regions with respect to enhancer-promoter proximity, functional transcription factor binding and regulatory function. We envision that technological improvements including single-molecule, multi-omics and spatial methods will bring further insight into the secrets of genome regulation.
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Affiliation(s)
- Liesbeth Minnoye
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | | | - Thomas Krausgruber
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Lixia Pan
- Laboratory of Epigenome Biology, Systems Biology Center, Division of Intramural Research, National Heart, Lung and Blood Institute, NIH, Bethesda, MD, USA
| | | | - Stefano Secchia
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Heidelberg, Germany
| | | | - Eileen E M Furlong
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Heidelberg, Germany
| | - Keji Zhao
- Laboratory of Epigenome Biology, Systems Biology Center, Division of Intramural Research, National Heart, Lung and Blood Institute, NIH, Bethesda, MD, USA
| | | | - Christoph Bock
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Institute of Artificial Intelligence and Decision Support, Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Stein Aerts
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
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17
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Luse DS, Parida M, Spector BM, Nilson KA, Price DH. A unified view of the sequence and functional organization of the human RNA polymerase II promoter. Nucleic Acids Res 2020; 48:7767-7785. [PMID: 32597978 PMCID: PMC7641323 DOI: 10.1093/nar/gkaa531] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 05/31/2020] [Accepted: 06/24/2020] [Indexed: 12/20/2022] Open
Abstract
To better understand human RNA polymerase II (Pol II) promoters in the context of promoter-proximal pausing and local chromatin organization, 5′ and 3′ ends of nascent capped transcripts and the locations of nearby nucleosomes were accurately identified through sequencing at exceptional depth. High-quality visualization tools revealed a preferred sequence that defines over 177 000 core promoters with strengths varying by >10 000-fold. This sequence signature encompasses and better defines the binding site for TFIID and is surprisingly invariant over a wide range of promoter strength. We identified a sequence motif associated with promoter-proximal pausing and demonstrated that cap methylation only begins once transcripts are about 30 nt long. Mapping also revealed a ∼150 bp periodic downstream sequence element (PDE) following the typical pause location, strongly suggestive of a +1 nucleosome positioning element. A nuclear run-off assay utilizing the unique properties of the DNA fragmentation factor (DFF) coupled with sequencing of DFF protected fragments demonstrated that a +1 nucleosome is present downstream of paused Pol II. Our data more clearly define the human Pol II promoter: a TFIID binding site with built-in downstream information directing ubiquitous promoter-proximal pausing and downstream nucleosome location.
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Affiliation(s)
- Donal S Luse
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Mrutyunjaya Parida
- Department of Biochemistry, The University of Iowa, Iowa City, IA 52242, USA
| | - Benjamin M Spector
- Department of Biochemistry, The University of Iowa, Iowa City, IA 52242, USA
| | - Kyle A Nilson
- Department of Biochemistry, The University of Iowa, Iowa City, IA 52242, USA
| | - David H Price
- Department of Biochemistry, The University of Iowa, Iowa City, IA 52242, USA
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18
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Oh S, Jo Y, Jung S, Yoon S, Yoo KH. From genome sequencing to the discovery of potential biomarkers in liver disease. BMB Rep 2020. [PMID: 32475383 PMCID: PMC7330805 DOI: 10.5483/bmbrep.2020.53.6.074] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Chronic liver disease progresses through several stages, fatty liver, steatohepatitis, cirrhosis, and eventually, it leads to hepatocellular carcinoma (HCC) over a long period of time. Since a large proportion of patients with HCC are accompanied by cirrhosis, it is considered to be an important factor in the diagnosis of liver cancer. This is because cirrhosis leads to an irreversible harmful effect, but the early stages of chronic liver disease could be reversed to a healthy state. Therefore, the discovery of biomarkers that could identify the early stages of chronic liver disease is important to prevent serious liver damage. Biomarker discovery at liver cancer and cirrhosis has enhanced the development of sequencing technology. Next generation sequencing (NGS) is one of the representative technical innovations in the biological field in the recent decades and it is the most important thing to design for research on what type of sequencing methods are suitable and how to handle the analysis steps for data integration. In this review, we comprehensively summarized NGS techniques for identifying genome, transcriptome, DNA methylome and 3D/4D chromatin structure, and introduced framework of processing data set and integrating multi-omics data for uncovering biomarkers.
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Affiliation(s)
- Sumin Oh
- Laboratory of Biomedical Genomics, Department of Biological Sciences, Sookmyung Women’s University, Seoul 04310, Korea
- Research Institute of Women’s Health, Sookmyung Women’s University, Seoul 04310, Korea
| | - Yeeun Jo
- Laboratory of Biomedical Genomics, Department of Biological Sciences, Sookmyung Women’s University, Seoul 04310, Korea
| | - Sungju Jung
- Laboratory of Biomedical Genomics, Department of Biological Sciences, Sookmyung Women’s University, Seoul 04310, Korea
| | - Sumin Yoon
- Laboratory of Biomedical Genomics, Department of Biological Sciences, Sookmyung Women’s University, Seoul 04310, Korea
| | - Kyung Hyun Yoo
- Laboratory of Biomedical Genomics, Department of Biological Sciences, Sookmyung Women’s University, Seoul 04310, Korea
- Research Institute of Women’s Health, Sookmyung Women’s University, Seoul 04310, Korea
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19
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Hsieh THS, Cattoglio C, Slobodyanyuk E, Hansen AS, Rando OJ, Tjian R, Darzacq X. Resolving the 3D Landscape of Transcription-Linked Mammalian Chromatin Folding. Mol Cell 2020; 78:539-553.e8. [PMID: 32213323 PMCID: PMC7703524 DOI: 10.1016/j.molcel.2020.03.002] [Citation(s) in RCA: 373] [Impact Index Per Article: 74.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 01/28/2020] [Accepted: 03/02/2020] [Indexed: 01/31/2023]
Abstract
Whereas folding of genomes at the large scale of epigenomic compartments and topologically associating domains (TADs) is now relatively well understood, how chromatin is folded at finer scales remains largely unexplored in mammals. Here, we overcome some limitations of conventional 3C-based methods by using high-resolution Micro-C to probe links between 3D genome organization and transcriptional regulation in mouse stem cells. Combinatorial binding of transcription factors, cofactors, and chromatin modifiers spatially segregates TAD regions into various finer-scale structures with distinct regulatory features including stripes, dots, and domains linking promoters-to-promoters (P-P) or enhancers-to-promoters (E-P) and bundle contacts between Polycomb regions. E-P stripes extending from the edge of domains predominantly link co-expressed loci, often in the absence of CTCF and cohesin occupancy. Acute inhibition of transcription disrupts these gene-related folding features without altering higher-order chromatin structures. Our study uncovers previously obscured finer-scale genome organization, establishing functional links between chromatin folding and gene regulation.
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Affiliation(s)
- Tsung-Han S Hsieh
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, Berkeley, CA 94720, USA; CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA 94720, USA; Center for Computational Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Claudia Cattoglio
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, Berkeley, CA 94720, USA; CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Elena Slobodyanyuk
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, Berkeley, CA 94720, USA; CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Anders S Hansen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, Berkeley, CA 94720, USA; CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Oliver J Rando
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Robert Tjian
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, Berkeley, CA 94720, USA; CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, Berkeley, CA 94720, USA; CIRM Center of Excellence, University of California, Berkeley, Berkeley, CA 94720, USA; Center for Computational Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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20
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Ramani V, Qiu R, Shendure J. High Sensitivity Profiling of Chromatin Structure by MNase-SSP. Cell Rep 2020; 26:2465-2476.e4. [PMID: 30811994 PMCID: PMC6582983 DOI: 10.1016/j.celrep.2019.02.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 11/07/2018] [Accepted: 02/01/2019] [Indexed: 12/11/2022] Open
Abstract
A complete view of eukaryotic gene regulation requires that we accurately delineate how transcription factors (TFs) and nucleosomes are arranged along linear DNA in a sensitive, unbiased manner. Here we introduce MNase-SSP, a single-stranded sequencing library preparation method for nuclease-digested chromatin that enables simultaneous mapping of TF and nucleosome positions. As a proof of concept, we apply MNase-SSP toward the genome-wide, high-resolution mapping of nucleosome and TF occupancy in murine embryonic stem cells (mESCs). Compared with existing MNase-seq protocols, MNase-SSP markedly enriches for short DNA fragments, enabling detection of binding by subnucleosomal particles and TFs, in addition to nucleosomes. From these same data, we identify multiple, sequence-dependent binding modes of the architectural TF Ctcf and extend this analysis to the TF Nrsf/ Rest. Looking forward, we anticipate that single stranded protocol (SSP) adaptations of any protein-DNA interaction mapping technique (e.g., ChIP-exo and CUT&RUN) will enhance the information content of the resulting data. Ramani et al. describe MNase-SSP, a single-stranded DNA sequencing library preparation method for profiling chromatin structure. MNase-SSP libraries harbor diminished sequence bias and capture shorter DNA fragments compared to traditional MNase-seq libraries. Applying MNase-SSP to murine embryonic stem cells enables simultaneous analysis of nucleosomal, subnucleosomal, and transcription factor-DNA interactions genome-wide.
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Affiliation(s)
- Vijay Ramani
- Department of Genome Sciences, University of Washington, Seattle, WA, USA; Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
| | - Ruolan Qiu
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Jay Shendure
- Department of Genome Sciences, University of Washington, Seattle, WA, USA; Brotman-Baty Institute for Precision Medicine, Seattle, WA, USA; Howard Hughes Medical Institute, Seattle, WA, USA.
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21
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Oruba A, Saccani S, van Essen D. Role of cell-type specific nucleosome positioning in inducible activation of mammalian promoters. Nat Commun 2020; 11:1075. [PMID: 32103026 PMCID: PMC7044431 DOI: 10.1038/s41467-020-14950-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 02/10/2020] [Indexed: 12/18/2022] Open
Abstract
The organization of nucleosomes across functional genomic elements represents a critical layer of control. Here, we present a strategy for high-resolution nucleosome profiling at selected genomic features, and use this to analyse dynamic nucleosome positioning at inducible and cell-type-specific mammalian promoters. We find that nucleosome patterning at inducible promoters frequently resembles that at active promoters, even before stimulus-driven activation. Accordingly, the nucleosome profile at many inactive inducible promoters is sufficient to predict cell-type-specific responsiveness. Induction of gene expression is generally not associated with major changes to nucleosome patterning, and a subset of inducible promoters can be activated without stable nucleosome depletion from their transcription start sites. These promoters are generally dependent on remodelling enzymes for their inducible activation, and exhibit transient nucleosome depletion only at alleles undergoing transcription initiation. Together, these data reveal how the responsiveness of inducible promoters to activating stimuli is linked to cell-type-specific nucleosome patterning. Nucleosome organisation plays important roles in regulating functional genomic elements. Here, the authors use high-resolution profiling to analyse dynamic nucleosome positioning at inducible and cell-type-specific promoters, providing a global view of chromatin architecture at inducible promoters.
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Affiliation(s)
- Agata Oruba
- Max Planck Institute for Immunobiology & Epigenetics, Stübeweg 51, Freiburg, D79108, Germany
| | - Simona Saccani
- Max Planck Institute for Immunobiology & Epigenetics, Stübeweg 51, Freiburg, D79108, Germany. .,Institute for Research on Cancer & Aging, Nice (IRCAN), 28 Avenue Valombrose, Nice, 06107, France.
| | - Dominic van Essen
- Max Planck Institute for Immunobiology & Epigenetics, Stübeweg 51, Freiburg, D79108, Germany. .,Institute for Research on Cancer & Aging, Nice (IRCAN), 28 Avenue Valombrose, Nice, 06107, France.
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22
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Epigenome Regulation by Dynamic Nucleosome Unwrapping. Trends Biochem Sci 2020; 45:13-26. [PMID: 31630896 PMCID: PMC10168609 DOI: 10.1016/j.tibs.2019.09.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 09/09/2019] [Accepted: 09/13/2019] [Indexed: 12/12/2022]
Abstract
Gene regulation in eukaryotes requires the controlled access of sequence-specific transcription factors (TFs) to their sites in a chromatin landscape dominated by nucleosomes. Nucleosomes are refractory to TF binding, and often must be removed from regulatory regions. Recent genomic studies together with in vitro measurements suggest that the nucleosome barrier to TF binding is modulated by dynamic nucleosome unwrapping governed by ATP-dependent chromatin remodelers. Genome-wide occupancy and the regulation of subnucleosomal intermediates have gained recent attention with the application of high-resolution approaches for precision mapping of protein-DNA interactions. We summarize here recent findings on nucleosome substructures and TF binding dynamics, and highlight how unwrapped nucleosomal intermediates provide a novel signature of active chromatin.
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23
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Klein DC, Hainer SJ. Genomic methods in profiling DNA accessibility and factor localization. Chromosome Res 2019; 28:69-85. [PMID: 31776829 PMCID: PMC7125251 DOI: 10.1007/s10577-019-09619-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/10/2019] [Accepted: 10/15/2019] [Indexed: 12/24/2022]
Abstract
Recent advancements in next-generation sequencing technologies and accompanying reductions in cost have led to an explosion of techniques to examine DNA accessibility and protein localization on chromatin genome-wide. Generally, accessible regions of chromatin are permissive for factor binding and are therefore hotspots for regulation of gene expression; conversely, genomic regions that are highly occupied by histone proteins are not permissive for factor binding and are less likely to be active regulatory regions. Identifying regions of differential accessibility can be useful to uncover putative gene regulatory regions, such as enhancers, promoters, and insulators. In addition, DNA-binding proteins, such as transcription factors that preferentially bind certain DNA sequences and histone proteins that form the core of the nucleosome, play essential roles in all DNA-templated processes. Determining the genomic localization of chromatin-bound proteins is therefore essential in determining functional roles, sequence motifs important for factor binding, and regulatory networks controlling gene expression. In this review, we discuss techniques for determining DNA accessibility and nucleosome positioning (DNase-seq, FAIRE-seq, MNase-seq, and ATAC-seq) and techniques for detecting and functionally characterizing chromatin-bound proteins (ChIP-seq, DamID, and CUT&RUN). These methods have been optimized to varying degrees of resolution, specificity, and ease of use. Here, we outline some advantages and disadvantages of these techniques, their general protocols, and a brief discussion of their development. Together, these complimentary approaches have provided an unparalleled view of chromatin architecture and functional gene regulation.
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Affiliation(s)
- David C Klein
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Sarah J Hainer
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
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24
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Chen FX, Smith ER, Shilatifard A. Born to run: control of transcription elongation by RNA polymerase II. Nat Rev Mol Cell Biol 2019; 19:464-478. [PMID: 29740129 DOI: 10.1038/s41580-018-0010-5] [Citation(s) in RCA: 288] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The dynamic regulation of transcription elongation by RNA polymerase II (Pol II) is an integral part of the implementation of gene expression programmes during development. In most metazoans, the majority of transcribed genes exhibit transient pausing of Pol II at promoter-proximal regions, and the release of Pol II into gene bodies is controlled by many regulatory factors that respond to environmental and developmental cues. Misregulation of the elongation stage of transcription is implicated in cancer and other human diseases, suggesting that mechanistic understanding of transcription elongation control is therapeutically relevant. In this Review, we discuss the features, establishment and maintenance of Pol II pausing, the transition into productive elongation, the control of transcription elongation by enhancers and by factors of other cellular processes, such as topoisomerases and poly(ADP-ribose) polymerases (PARPs), and the potential of therapeutic targeting of the elongation stage of transcription by Pol II.
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Affiliation(s)
- Fei Xavier Chen
- Simpson Querrey Center for Epigenetics and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Edwin R Smith
- Simpson Querrey Center for Epigenetics and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Ali Shilatifard
- Simpson Querrey Center for Epigenetics and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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25
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Sun Y, Miao N, Sun T. Detect accessible chromatin using ATAC-sequencing, from principle to applications. Hereditas 2019; 156:29. [PMID: 31427911 PMCID: PMC6696680 DOI: 10.1186/s41065-019-0105-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/12/2019] [Indexed: 02/07/2023] Open
Abstract
Background Chromatin accessibility is crucial for gene expression regulation in specific cells and in multiple biological processes. Assay for Transposase Accessible Chromatin with high-throughput sequencing (ATAC-seq) is an effective way to reveal chromatin accessibility at a genome-wide level. Through ATAC-seq, produced reads from a small number of cells reflect accessible regions that correspond to nucleosome positioning and transcription factor binding sites, due to probing hyperactive Tn5 transposase to DNA sequence. Conclusion In this review, we summarize both principle and features of ATAC-seq, highlight its applications in basic and clinical research. ATAC-seq has generated comprehensive chromatin accessible maps, and is becoming a powerful tool to understand dynamic gene expression regulation in stem cells, early embryos and tumors.
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Affiliation(s)
- Yuanyuan Sun
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, 668 Jimei Road, Xiamen, 361021 Fujian China
| | - Nan Miao
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, 668 Jimei Road, Xiamen, 361021 Fujian China
| | - Tao Sun
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, 668 Jimei Road, Xiamen, 361021 Fujian China
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26
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Luo D, Kato D, Nogami J, Ohkawa Y, Kurumizaka H, Kono H. MNase, as a probe to study the sequence-dependent site exposures in the +1 nucleosomes of yeast. Nucleic Acids Res 2019; 46:7124-7137. [PMID: 29893974 PMCID: PMC6101533 DOI: 10.1093/nar/gky502] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 05/30/2018] [Indexed: 01/06/2023] Open
Abstract
The first nucleosomes in the downstream of transcription starting sites are called +1 nucleosomes, which are expected to be readily unwrapped for DNA transcription. To investigate DNA accessibility in +1 nucleosomes, MNase-seq experiments were carried out with 20 reconstituted +1 nucleosomes of budding yeast. Although MNase has been known for its sequence preference in DNA digestions, we confirmed that this sequence preference is overwhelmed by DNA accessibility by identifying the sequence-driven and accessibility-driven cleavages. Specifically, we find that sequences favoured by MNase at the end regions such as TA dinucleotide are prohibited from cleavage at the internal sites in the early stage of digestion. Nevertheless, sequences less favoured by MNase at the end regions such as AA/TT dinucleotide are predominantly cleaved at the internal sites in the early stage of digestion. Since AA/TT is known as a rigid dinucleotide step resistant to DNA bending, these internal cleavages reflect the local site exposures induced by DNA mechanics. As the DNA entry site of +1 nucleosomes in yeast is found AA/TT-rich, this sequence element may play a role in gene activation by reducing DNA–histone affinities along the direction of DNA transcription.
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Affiliation(s)
- Di Luo
- Molecular Modeling and Simulation Group, Department of Quantum Beam Life Science, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan
| | - Daiki Kato
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Jumpei Nogami
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yasuyuki Ohkawa
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hidetoshi Kono
- Molecular Modeling and Simulation Group, Department of Quantum Beam Life Science, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215, Japan
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27
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Wang Y, Wang A, Liu Z, Thurman AL, Powers LS, Zou M, Zhao Y, Hefel A, Li Y, Zabner J, Au KF. Single-molecule long-read sequencing reveals the chromatin basis of gene expression. Genome Res 2019; 29:1329-1342. [PMID: 31201211 PMCID: PMC6673713 DOI: 10.1101/gr.251116.119] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/10/2019] [Indexed: 11/25/2022]
Abstract
Genome-wide chromatin accessibility and nucleosome occupancy profiles have been widely investigated, while the long-range dynamics remain poorly studied at the single-cell level. Here, we present a new experimental approach, methyltransferase treatment followed by single-molecule long-read sequencing (MeSMLR-seq), for long-range mapping of nucleosomes and chromatin accessibility at single DNA molecules and thus achieve comprehensive-coverage characterization of the corresponding heterogeneity. MeSMLR-seq offers direct measurements of both nucleosome-occupied and nucleosome-evicted regions on a single DNA molecule, which is challenging for many existing methods. We applied MeSMLR-seq to haploid yeast, where single DNA molecules represent single cells, and thus we could investigate the combinatorics of many (up to 356) nucleosomes at long range in single cells. We illustrated the differential organization principles of nucleosomes surrounding the transcription start site for silent and actively transcribed genes, at the single-cell level and in the long-range scale. The heterogeneous patterns of chromatin status spanning multiple genes were phased. Together with single-cell RNA-seq data, we quantitatively revealed how chromatin accessibility correlated with gene transcription positively in a highly heterogeneous scenario. Moreover, we quantified the openness of promoters and investigated the coupled chromatin changes of adjacent genes at single DNA molecules during transcription reprogramming. In addition, we revealed the coupled changes of chromatin accessibility for two neighboring glucose transporter genes in response to changes in glucose concentration.
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Affiliation(s)
- Yunhao Wang
- Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | - Anqi Wang
- Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | - Zujun Liu
- Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | - Andrew L Thurman
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | - Linda S Powers
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | - Meng Zou
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | - Yue Zhao
- Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | - Adam Hefel
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | - Yunyi Li
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | - Joseph Zabner
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | - Kin Fai Au
- Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA.,Department of Biostatistics, University of Iowa, Iowa City, Iowa 52242, USA
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28
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Starks RR, Biswas A, Jain A, Tuteja G. Combined analysis of dissimilar promoter accessibility and gene expression profiles identifies tissue-specific genes and actively repressed networks. Epigenetics Chromatin 2019; 12:16. [PMID: 30795793 PMCID: PMC6385419 DOI: 10.1186/s13072-019-0260-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 02/12/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The assay for transposase-accessible chromatin (ATAC-seq) is a powerful method to examine chromatin accessibility. While many studies have reported a positive correlation between gene expression and promoter accessibility, few have investigated the genes that deviate from this trend. In this study, we aimed to understand the relationship between gene expression and promoter accessibility in multiple cell types while also identifying gene regulatory networks in the placenta, an understudied organ that is critical for a successful pregnancy. RESULTS We started by assaying the open chromatin landscape in the mid-gestation placenta, when the fetal vasculature has started developing. After incorporating transcriptomic data generated in the placenta at the same time point, we grouped genes based on their expression levels and ATAC-seq promoter coverage. We found that the genes with the strongest correlation (high expression and high coverage) are likely involved in housekeeping functions, whereas tissue-specific genes were highly expressed and had only medium-low coverage. We also predicted that genes with medium-low expression and high promoter coverage were actively repressed. Within this group, we extracted a protein-protein interaction network enriched for neuronal functions, likely preventing the cells from adopting a neuronal fate. We further confirmed that a repressive histone mark is bound to the promoters of genes in this network. Finally, we ran our pipeline using ATAC-seq and RNA-seq data generated in ten additional cell types. We again found that genes with the strongest correlation are enriched for housekeeping functions and that genes with medium-low promoter coverage and high expression are more likely to be tissue-specific. These results demonstrate that only two data types, both of which require relatively low starting material to generate and are becoming more commonly available, can be integrated to understand multiple aspects of gene regulation. CONCLUSIONS Within the placenta, we identified an active placenta-specific gene network as well as a repressed neuronal network. Beyond the placenta, we demonstrate that ATAC-seq data and RNA-seq data can be integrated to identify tissue-specific genes and actively repressed gene networks in multiple cell types.
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Affiliation(s)
- Rebekah R. Starks
- Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011 USA
- Bioinformatics and Computational Biology, Iowa State University, Ames, IA 50011 USA
| | - Anilisa Biswas
- Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011 USA
- Molecular, Cellular, and Developmental Biology, Iowa State University, Ames, IA 50011 USA
| | - Ashish Jain
- Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011 USA
- Bioinformatics and Computational Biology, Iowa State University, Ames, IA 50011 USA
| | - Geetu Tuteja
- Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011 USA
- Bioinformatics and Computational Biology, Iowa State University, Ames, IA 50011 USA
- Molecular, Cellular, and Developmental Biology, Iowa State University, Ames, IA 50011 USA
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29
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Schwartz U, Németh A, Diermeier S, Exler JH, Hansch S, Maldonado R, Heizinger L, Merkl R, Längst G. Characterizing the nuclease accessibility of DNA in human cells to map higher order structures of chromatin. Nucleic Acids Res 2019; 47:1239-1254. [PMID: 30496478 PMCID: PMC6379673 DOI: 10.1093/nar/gky1203] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/17/2018] [Accepted: 11/22/2018] [Indexed: 12/22/2022] Open
Abstract
Packaging of DNA into chromatin regulates DNA accessibility and consequently all DNA-dependent processes. The nucleosome is the basic packaging unit of DNA forming arrays that are suggested, by biochemical studies, to fold hierarchically into ordered higher-order structures of chromatin. This organization has been recently questioned using microscopy techniques, proposing an irregular structure. To address the principles of chromatin organization, we applied an in situ differential MNase-seq strategy and analyzed in silico the results of complete and partial digestions of human chromatin. We investigated whether different levels of chromatin packaging exist in the cell. We assessed the accessibility of chromatin within distinct domains of kb to Mb genomic regions, performed statistical analyses and computer modelling. We found no difference in MNase accessibility, suggesting no difference in fiber folding between domains of euchromatin and heterochromatin or between other sequence and epigenomic features of chromatin. Thus, our data suggests the absence of differentially organized domains of higher-order structures of chromatin. Moreover, we identified only local structural changes, with individual hyper-accessible nucleosomes surrounding regulatory elements, such as enhancers and transcription start sites. The regulatory sites per se are occupied with structurally altered nucleosomes, exhibiting increased MNase sensitivity. Our findings provide biochemical evidence that supports an irregular model of large-scale chromatin organization.
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Affiliation(s)
- Uwe Schwartz
- Department of Biochemistry III, University of Regensburg, University of Regensburg, 93040 Regensburg, Germany
| | - Attila Németh
- Department of Biochemistry III, University of Regensburg, University of Regensburg, 93040 Regensburg, Germany
| | - Sarah Diermeier
- Department of Biochemistry III, University of Regensburg, University of Regensburg, 93040 Regensburg, Germany
| | - Josef H Exler
- Department of Biochemistry III, University of Regensburg, University of Regensburg, 93040 Regensburg, Germany
| | - Stefan Hansch
- Department of Biochemistry III, University of Regensburg, University of Regensburg, 93040 Regensburg, Germany
| | - Rodrigo Maldonado
- Department of Biochemistry III, University of Regensburg, University of Regensburg, 93040 Regensburg, Germany
| | - Leonhard Heizinger
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Rainer Merkl
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Gernot Längst
- Department of Biochemistry III, University of Regensburg, University of Regensburg, 93040 Regensburg, Germany
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30
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Nishimura M, Nozawa K, Kurumizaka H. Crystallographic analysis of the overlapping dinucleosome as a novel chromatin unit. Biophys Physicobiol 2019; 15:251-254. [PMID: 30713825 PMCID: PMC6353640 DOI: 10.2142/biophysico.15.0_251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 11/18/2018] [Indexed: 12/01/2022] Open
Abstract
Recent evidence has suggested that chromatin is not simply repeats of the canonical nucleosome, called the “octasome”, but may include diverse repertoires of basic structural units. During the transcription process, a nucleosome is repositioned by a chromatin remodeler and collides with a neighboring nucleosome, thus creating an unusual nucleosome substructure termed the “overlapping dinucleosome”. We previously developed a method for the large-scale preparation of the overlapping dinucleosome. This method enabled us to solve the crystal structure of the overlapping dinucleosome, which revealed an unexpected structure composed of an octameric histone core associated with a hexameric histone core lacking one H2A-H2B dimer.
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Affiliation(s)
- Masahiro Nishimura
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.,Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Kayo Nozawa
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.,Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.,Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan
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31
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Brahma S, Henikoff S. RSC-Associated Subnucleosomes Define MNase-Sensitive Promoters in Yeast. Mol Cell 2018; 73:238-249.e3. [PMID: 30554944 PMCID: PMC6475595 DOI: 10.1016/j.molcel.2018.10.046] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 09/04/2018] [Accepted: 10/30/2018] [Indexed: 02/07/2023]
Abstract
The classic view of nucleosome organization at active promoters is that two well-positioned nucleosomes flank a nucleosome-depleted region (NDR). However, this view has been recently disputed by contradictory reports as to whether wider (≳150 bp) NDRs instead contain unstable, micrococcal nuclease-sensitive ("fragile") nucleosomal particles. To determine the composition of fragile particles, we introduce CUT&RUN.ChIP, in which targeted nuclease cleavage and release is followed by chromatin immunoprecipitation. We find that fragile particles represent the occupancy of the RSC (remodeling the structure of chromatin) nucleosome remodeling complex and RSC-bound, partially unwrapped nucleosomal intermediates. We also find that general regulatory factors (GRFs) bind to partially unwrapped nucleosomes at these promoters. We propose that RSC binding and its action cause nucleosomes to unravel, facilitate subsequent binding of GRFs, and constitute a dynamic cycle of nucleosome deposition and clearance at the subset of wide Pol II promoter NDRs.
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Affiliation(s)
- Sandipan Brahma
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Howard Hughes Medical Institute, USA.
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32
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Potdar P, Pinto P, D’Souza N, Joshi P, Malwade A, Sen S. A Novel Method to Generate MNase Ladders Reveal Rapid Chromatin Remodeling upon Gametogenesis and Mating in Chlamydomonas. Protist 2018; 169:632-644. [DOI: 10.1016/j.protis.2018.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/22/2018] [Accepted: 06/27/2018] [Indexed: 02/06/2023]
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33
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Umeyama T, Ito T. DMS-seq for In Vivo Genome-Wide Mapping of Protein-DNA Interactions and Nucleosome Centers. ACTA ACUST UNITED AC 2018; 123:e60. [PMID: 29927065 DOI: 10.1002/cpmb.60] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The genome exerts its functions through interactions with proteins. Hence, comprehensive identification of protein-occupied sites by genomic footprinting is critical to an in-depth understanding of genome functions. This unit describes the protocol of dimethyl sulfate-sequencing (DMS-seq). DMS is an alkylating reagent that methylates guanine and adenine in double-stranded DNA. DMS added to the culture medium readily enters the cell and methylates its DNA throughout the genome except for the regions bound by proteins, thereby obviating the need for nuclear isolation in genomic footprinting. Polyamine/AP-endonuclease treatment of DNA isolated from DMS-treated cells induces cleavages at the methylated sites. Deep sequencing of these fragments identifies protein-bound sites as peaks of protected fragments or troughs of cleavage sites. Furthermore, DMS displays an unexpected preference to nucleosome centers, enabling their direct detection without genetic manipulation. Therefore, DMS-seq provides a unique method for non-targeted profiling of in vivo protein-DNA interactions. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Taichi Umeyama
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
- Laboratory for Microbiome Sciences, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Takashi Ito
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
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34
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Characterization of the Nucleosome Landscape by Micrococcal Nuclease-Sequencing (MNase-seq). Methods Mol Biol 2018; 1689:83-101. [PMID: 29027167 DOI: 10.1007/978-1-4939-7380-4_8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
MNase-seq allows the genome-wide examination of the nucleosome landscape by determination of nucleosome positioning and occupancy. Typically, native or formaldehyde fixed chromatin is subjected to digestion by micrococcal nuclease (MNase), which degrades linker DNA and yields mainly mono-nucleosomes. The resulting material can be processed directly or can be subjected to an optional chromatin immunoprecipitation step (MNase-ChIP-seq). De-crosslinked and purified DNA is then subjected to next-generation sequencing. The protocol presented here has been tailored for the analysis of nucleosome landscape in the malaria parasite, Plasmodium falciparum, but most steps are directly applicable to other cell types. We also discuss general considerations for experimental design and computational analysis, which are crucial for accurate investigation of the nucleosome landscape.
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35
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Umeyama T, Ito T. DMS-Seq for In Vivo Genome-wide Mapping of Protein-DNA Interactions and Nucleosome Centers. Cell Rep 2018; 21:289-300. [PMID: 28978481 DOI: 10.1016/j.celrep.2017.09.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 07/31/2017] [Accepted: 09/08/2017] [Indexed: 01/05/2023] Open
Abstract
Protein-DNA interactions provide the basis for chromatin structure and gene regulation. Comprehensive identification of protein-occupied sites is thus vital to an in-depth understanding of genome function. Dimethyl sulfate (DMS) is a chemical probe that has long been used to detect footprints of DNA-bound proteins in vitro and in vivo. Here, we describe a genomic footprinting method, dimethyl sulfate sequencing (DMS-seq), which exploits the cell-permeable nature of DMS to obviate the need for nuclear isolation. This feature makes DMS-seq simple in practice and removes the potential risk of protein re-localization during nuclear isolation. DMS-seq successfully detects transcription factors bound to cis-regulatory elements and non-canonical chromatin particles in nucleosome-free regions. Furthermore, an unexpected preference of DMS confers on DMS-seq a unique potential to directly detect nucleosome centers without using genetic manipulation. We expect that DMS-seq will serve as a characteristic method for genome-wide interrogation of in vivo protein-DNA interactions.
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Affiliation(s)
- Taichi Umeyama
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Agency for Medical Research and Development (AMED), Tokyo 100-0004, Japan; Laboratory for Microbiome Sciences, RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | - Takashi Ito
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Agency for Medical Research and Development (AMED), Tokyo 100-0004, Japan.
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36
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Chereji RV, Clark DJ. Major Determinants of Nucleosome Positioning. Biophys J 2018; 114:2279-2289. [PMID: 29628211 DOI: 10.1016/j.bpj.2018.03.015] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 02/27/2018] [Accepted: 03/08/2018] [Indexed: 12/21/2022] Open
Abstract
The compact structure of the nucleosome limits DNA accessibility and inhibits the binding of most sequence-specific proteins. Nucleosomes are not randomly located on the DNA but positioned with respect to the DNA sequence, suggesting models in which critical binding sites are either exposed in the linker, resulting in activation, or buried inside a nucleosome, resulting in repression. The mechanisms determining nucleosome positioning are therefore of paramount importance for understanding gene regulation and other events that occur in chromatin, such as transcription, replication, and repair. Here, we review our current understanding of the major determinants of nucleosome positioning: DNA sequence, nonhistone DNA-binding proteins, chromatin-remodeling enzymes, and transcription. We outline the major challenges for the future: elucidating the precise mechanisms of chromatin opening and promoter activation, identifying the complexes that occupy promoters, and understanding the multiscale problem of chromatin fiber organization.
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Affiliation(s)
- Răzvan V Chereji
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute for Child Health and Human Development, National Institutes of Health, Bethesda, Maryland.
| | - David J Clark
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute for Child Health and Human Development, National Institutes of Health, Bethesda, Maryland.
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37
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Yu Z, Cowan JA. Metal complexes promoting catalytic cleavage of nucleic acids-biochemical tools and therapeutics. Curr Opin Chem Biol 2018; 43:37-42. [PMID: 29153936 PMCID: PMC5847438 DOI: 10.1016/j.cbpa.2017.10.029] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/26/2017] [Accepted: 10/29/2017] [Indexed: 01/21/2023]
Abstract
The development of metal complexes that promote degradation of nucleic acids has garnered significant interest as a result of their broad range of potential application. This review focuses on recent progress in the design and synthesis of metal complexes as artificial nucleases that promote either hydrolytic or oxidative cleavage of nucleic acids. Illustrative examples demonstrate the versatility of artificial nucleases for in vitro applications as molecular tools to address biochemical problems, as well as their potential use as therapeutic agents. We also address future challenges for improvement and avenues for further investigation.
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Affiliation(s)
- Zhen Yu
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
| | - J A Cowan
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA.
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38
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Fuse T, Katsumata K, Morohoshi K, Mukai Y, Ichikawa Y, Kurumizaka H, Yanagida A, Urano T, Kato H, Shimizu M. Parallel mapping with site-directed hydroxyl radicals and micrococcal nuclease reveals structural features of positioned nucleosomes in vivo. PLoS One 2017; 12:e0186974. [PMID: 29073207 PMCID: PMC5658119 DOI: 10.1371/journal.pone.0186974] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 10/11/2017] [Indexed: 12/17/2022] Open
Abstract
Micrococcal nuclease (MNase) has been widely used for analyses of nucleosome locations in many organisms. However, due to its sequence preference, the interpretations of the positions and occupancies of nucleosomes using MNase have remained controversial. Next-generation sequencing (NGS) has also been utilized for analyses of MNase-digests, but some technical biases are commonly present in the NGS experiments. Here, we established a gel-based method to map nucleosome positions in Saccharomyces cerevisiae, using isolated nuclei as the substrate for the histone H4 S47C-site-directed chemical cleavage in parallel with MNase digestion. The parallel mapping allowed us to compare the chemically and enzymatically cleaved sites by indirect end-labeling and primer extension mapping, and thus we could determine the nucleosome positions and the sizes of the nucleosome-free regions (or nucleosome-depleted regions) more accurately, as compared to nucleosome mapping by MNase alone. The analysis also revealed that the structural features of the nucleosomes flanked by the nucleosome-free region were different from those within regularly arrayed nucleosomes, showing that the structures and dynamics of individual nucleosomes strongly depend on their locations. Moreover, we demonstrated that the parallel mapping results were generally consistent with the previous genome-wide chemical mapping and MNase-Seq results. Thus, the gel-based parallel mapping will be useful for the analysis of a specific locus under various conditions.
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Affiliation(s)
- Tomohiro Fuse
- Department of Chemistry, Graduate School of Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University, Hino, Tokyo, Japan
| | - Koji Katsumata
- Department of Chemistry, Graduate School of Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University, Hino, Tokyo, Japan
| | - Koya Morohoshi
- Department of Chemistry, Graduate School of Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University, Hino, Tokyo, Japan
| | - Yukio Mukai
- Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan
| | - Yuichi Ichikawa
- Graduate School of Advanced Science and Engineering/RISE/IMSB, Waseda University, Shinjuku-ku, Tokyo, Japan
| | - Hitoshi Kurumizaka
- Graduate School of Advanced Science and Engineering/RISE/IMSB, Waseda University, Shinjuku-ku, Tokyo, Japan
| | - Akio Yanagida
- School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji, Tokyo, Japan
| | - Takeshi Urano
- Department of Biochemistry, Shimane University School of Medicine, Izumo, Shimane, Japan
| | - Hiroaki Kato
- Department of Biochemistry, Shimane University School of Medicine, Izumo, Shimane, Japan
| | - Mitsuhiro Shimizu
- Department of Chemistry, Graduate School of Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University, Hino, Tokyo, Japan
- * E-mail:
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39
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Kubik S, Bruzzone MJ, Albert B, Shore D. A Reply to "MNase-Sensitive Complexes in Yeast: Nucleosomes and Non-histone Barriers," by Chereji et al. Mol Cell 2017; 65:578-580. [PMID: 28157510 DOI: 10.1016/j.molcel.2017.01.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 01/05/2017] [Accepted: 01/06/2017] [Indexed: 11/25/2022]
Abstract
In this issue of Molecular Cell, Chereji et al. (2017) present new data on MNase-sensitive particles previously identified upstream of transcription start sites at many promoters in budding yeast, and they argue, based upon negative histone-ChIP results, that they are non-nucleosomal signals generated by transcription factors (TFs). We show instead, based upon functional experiments where the relevant TFs are rapidly depleted, that this explanation does not hold, and we argue instead that histone ChIP and chemical cleavage assays have a limited capacity to capture these highly dynamic, MNase-sensitive "fragile" nucleosomes.
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Affiliation(s)
- Slawomir Kubik
- Department of Molecular Biology and Institute for Genetics and Genomics in Geneva (iGE3), 30 quai Ernest-Ansermet, Geneva 4, CH-1211 Switzerland
| | - Maria Jessica Bruzzone
- Department of Molecular Biology and Institute for Genetics and Genomics in Geneva (iGE3), 30 quai Ernest-Ansermet, Geneva 4, CH-1211 Switzerland
| | - Benjamin Albert
- Department of Molecular Biology and Institute for Genetics and Genomics in Geneva (iGE3), 30 quai Ernest-Ansermet, Geneva 4, CH-1211 Switzerland
| | - David Shore
- Department of Molecular Biology and Institute for Genetics and Genomics in Geneva (iGE3), 30 quai Ernest-Ansermet, Geneva 4, CH-1211 Switzerland.
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40
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MNase-Sensitive Complexes in Yeast: Nucleosomes and Non-histone Barriers. Mol Cell 2017; 65:565-577.e3. [PMID: 28157509 DOI: 10.1016/j.molcel.2016.12.009] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 09/15/2016] [Accepted: 12/13/2016] [Indexed: 11/24/2022]
Abstract
Micrococcal nuclease (MNase) is commonly used to map nucleosomes genome-wide, but nucleosome maps are affected by the degree of digestion. It has been proposed that many yeast promoters are not nucleosome-free but instead occupied by easily digested, unstable, "fragile" nucleosomes. We analyzed the histone content of all MNase-sensitive complexes by MNase-ChIP-seq and sonication-ChIP-seq. We find that yeast promoters are predominantly bound by non-histone protein complexes, with little evidence for fragile nucleosomes. We do detect MNase-sensitive nucleosomes elsewhere in the genome, including at transcription termination sites. However, they have high A/T content, suggesting that MNase sensitivity does not indicate instability, but rather the preference of MNase for A/T-rich DNA, such that A/T-rich nucleosomes are digested faster than G/C-rich nucleosomes. We confirm our observations by analyzing ChIP-exo, chemical mapping, and ATAC-seq data from other laboratories. Thus, histone ChIP-seq experiments are essential to distinguish nucleosomes from other DNA-binding proteins that protect against MNase.
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41
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Abstract
This review by Vo ngoc et al. expands the view of the RNA polymerase II core promoter, which is comprised of classical DNA sequence motifs, sequence-specific DNA-binding transcription factors, chromatin signals, and DNA structure. The signals that direct the initiation of transcription ultimately converge at the core promoter, which is the gateway to transcription. Here we provide an overview of the RNA polymerase II core promoter in bilateria (bilaterally symmetric animals). The core promoter is diverse in terms of its composition and function yet is also punctilious, as it acts with strict rules and precision. We additionally describe an expanded view of the core promoter that comprises the classical DNA sequence motifs, sequence-specific DNA-binding transcription factors, chromatin signals, and DNA structure. This model may eventually lead to a more unified conceptual understanding of the core promoter.
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Affiliation(s)
- Long Vo Ngoc
- Section of Molecular Biology, University of California at San Diego, La Jolla, California 92093, USA
| | - Yuan-Liang Wang
- Section of Molecular Biology, University of California at San Diego, La Jolla, California 92093, USA
| | - George A Kassavetis
- Section of Molecular Biology, University of California at San Diego, La Jolla, California 92093, USA
| | - James T Kadonaga
- Section of Molecular Biology, University of California at San Diego, La Jolla, California 92093, USA
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42
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Voong LN, Xi L, Wang JP, Wang X. Genome-wide Mapping of the Nucleosome Landscape by Micrococcal Nuclease and Chemical Mapping. Trends Genet 2017; 33:495-507. [PMID: 28693826 DOI: 10.1016/j.tig.2017.05.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 05/10/2017] [Accepted: 05/30/2017] [Indexed: 12/30/2022]
Abstract
Nucleosomes regulate the transcription output of the genome by occluding the underlying DNA sequences from DNA-binding proteins that must act on it. Knowledge of the precise locations of nucleosomes in the genome is thus essential towards understanding how transcription is regulated. Current nucleosome-mapping strategies involve digesting chromatin with nucleases or chemical cleavage followed by high-throughput sequencing. In this review, we compare the traditional micrococcal nuclease (MNase)-based approach with a chemical cleavage strategy, with discussion on the important insights each has uncovered about the role of nucleosomes in shaping transcriptional processes.
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Affiliation(s)
- Lilien N Voong
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Liqun Xi
- Department of Statistics, Northwestern University, Evanston, IL 60208, USA
| | - Ji-Ping Wang
- Department of Statistics, Northwestern University, Evanston, IL 60208, USA.
| | - Xiaozhong Wang
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
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43
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Understanding nucleosome dynamics and their links to gene expression and DNA replication. Nat Rev Mol Cell Biol 2017; 18:548-562. [PMID: 28537572 DOI: 10.1038/nrm.2017.47] [Citation(s) in RCA: 335] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Advances in genomics technology have provided the means to probe myriad chromatin interactions at unprecedented spatial and temporal resolution. This has led to a profound understanding of nucleosome organization within the genome, revealing that nucleosomes are highly dynamic. Nucleosome dynamics are governed by a complex interplay of histone composition, histone post-translational modifications, nucleosome occupancy and positioning within chromatin, which are influenced by numerous regulatory factors, including general regulatory factors, chromatin remodellers, chaperones and polymerases. It is now known that these dynamics regulate diverse cellular processes ranging from gene transcription to DNA replication and repair.
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Mueller B, Mieczkowski J, Kundu S, Wang P, Sadreyev R, Tolstorukov MY, Kingston RE. Widespread changes in nucleosome accessibility without changes in nucleosome occupancy during a rapid transcriptional induction. Genes Dev 2017; 31:451-462. [PMID: 28356342 PMCID: PMC5393060 DOI: 10.1101/gad.293118.116] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 02/27/2017] [Indexed: 12/20/2022]
Abstract
Activation of transcription requires alteration of chromatin by complexes that increase the accessibility of nucleosomal DNA. Removing nucleosomes from regulatory sequences has been proposed to play a significant role in activation. We tested whether changes in nucleosome occupancy occurred on the set of genes that is activated by the unfolded protein response (UPR). We observed no decrease in occupancy on most promoters, gene bodies, and enhancers. Instead, there was an increase in the accessibility of nucleosomes, as measured by micrococcal nuclease (MNase) digestion and ATAC-seq (assay for transposase-accessible chromatin [ATAC] using sequencing), that did not result from removal of the nucleosome. Thus, changes in nucleosome accessibility predominate over changes in nucleosome occupancy during rapid transcriptional induction during the UPR.
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Affiliation(s)
- Britta Mueller
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Jakub Mieczkowski
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Sharmistha Kundu
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Peggy Wang
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Ruslan Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.,Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Michael Y Tolstorukov
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Robert E Kingston
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
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45
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Kubik S, Bruzzone MJ, Shore D. Establishing nucleosome architecture and stability at promoters: Roles of pioneer transcription factors and the RSC chromatin remodeler. Bioessays 2017; 39. [PMID: 28345796 DOI: 10.1002/bies.201600237] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Improvements in deep sequencing, together with methods to rapidly deplete essential transcription factors (TFs) and chromatin remodelers, have recently led to a more detailed picture of promoter nucleosome architecture in yeast and its relationship to transcriptional regulation. These studies revealed that ∼40% of all budding yeast protein-coding genes possess a unique promoter structure, where we propose that an unusually unstable nucleosome forms immediately upstream of the transcription start site (TSS). This "fragile" nucleosome (FN) promoter architecture relies on the combined action of the essential RSC (Remodels Structure of Chromatin) nucleosome remodeler and pioneer transcription factors (PTFs). FNs are associated with genes whose expression is high, coupled to cell growth, and characterized by low cell-to-cell variability (noise), suggesting that they may promote these features. Recent studies in metazoans suggest that the presence of dynamic nucleosomes upstream of the TSS at highly expressed genes may be conserved throughout evolution.
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Affiliation(s)
- Slawomir Kubik
- Department of Molecular Biology and Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - Maria Jessica Bruzzone
- Department of Molecular Biology and Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - David Shore
- Department of Molecular Biology and Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Geneva, Switzerland
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46
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Vainshtein Y, Rippe K, Teif VB. NucTools: analysis of chromatin feature occupancy profiles from high-throughput sequencing data. BMC Genomics 2017; 18:158. [PMID: 28196481 PMCID: PMC5309995 DOI: 10.1186/s12864-017-3580-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 02/10/2017] [Indexed: 12/21/2022] Open
Abstract
Background Biomedical applications of high-throughput sequencing methods generate a vast amount of data in which numerous chromatin features are mapped along the genome. The results are frequently analysed by creating binary data sets that link the presence/absence of a given feature to specific genomic loci. However, the nucleosome occupancy or chromatin accessibility landscape is essentially continuous. It is currently a challenge in the field to cope with continuous distributions of deep sequencing chromatin readouts and to integrate the different types of discrete chromatin features to reveal linkages between them. Results Here we introduce the NucTools suite of Perl scripts as well as MATLAB- and R-based visualization programs for a nucleosome-centred downstream analysis of deep sequencing data. NucTools accounts for the continuous distribution of nucleosome occupancy. It allows calculations of nucleosome occupancy profiles averaged over several replicates, comparisons of nucleosome occupancy landscapes between different experimental conditions, and the estimation of the changes of integral chromatin properties such as the nucleosome repeat length. Furthermore, NucTools facilitates the annotation of nucleosome occupancy with other chromatin features like binding of transcription factors or architectural proteins, and epigenetic marks like histone modifications or DNA methylation. The applications of NucTools are demonstrated for the comparison of several datasets for nucleosome occupancy in mouse embryonic stem cells (ESCs) and mouse embryonic fibroblasts (MEFs). Conclusions The typical workflows of data processing and integrative analysis with NucTools reveal information on the interplay of nucleosome positioning with other features such as for example binding of a transcription factor CTCF, regions with stable and unstable nucleosomes, and domains of large organized chromatin K9me2 modifications (LOCKs). As potential limitations and problems we discuss how inter-replicate variability of MNase-seq experiments can be addressed. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3580-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yevhen Vainshtein
- Functional Genomics Group, Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Nobelstraße 12, 70569, Stuttgart, Germany.
| | - Karsten Rippe
- Research Group Genome Organization & Function, German Cancer Research Center (DKFZ) and Bioquant, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Vladimir B Teif
- School of Biological Sciences, University of Essex, Wivenhoe Park, CO4 3SQ, Colchester, UK.
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Voong LN, Xi L, Sebeson AC, Xiong B, Wang JP, Wang X. Insights into Nucleosome Organization in Mouse Embryonic Stem Cells through Chemical Mapping. Cell 2016; 167:1555-1570.e15. [PMID: 27889238 DOI: 10.1016/j.cell.2016.10.049] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 09/05/2016] [Accepted: 10/27/2016] [Indexed: 12/21/2022]
Abstract
Nucleosome organization influences gene activity by controlling DNA accessibility to transcription machinery. Here, we develop a chemical biology approach to determine mammalian nucleosome positions genome-wide. We uncovered surprising features of nucleosome organization in mouse embryonic stem cells. In contrast to the prevailing model, we observe that for nearly all mouse genes, a class of fragile nucleosomes occupies previously designated nucleosome-depleted regions around transcription start sites and transcription termination sites. We show that nucleosomes occupy DNA targets for a subset of DNA-binding proteins, including CCCTC-binding factor (CTCF) and pluripotency factors. Furthermore, we provide evidence that promoter-proximal nucleosomes, with the +1 nucleosome in particular, contribute to the pausing of RNA polymerase II. Lastly, we find a characteristic preference for nucleosomes at exon-intron junctions. Taken together, we establish an accurate method for defining the nucleosome landscape and provide a valuable resource for studying nucleosome-mediated gene regulation in mammalian cells.
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Affiliation(s)
- Lilien N Voong
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Liqun Xi
- Department of Statistics, Northwestern University, Evanston, IL 60208, USA
| | - Amy C Sebeson
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Bin Xiong
- Department of Statistics, Northwestern University, Evanston, IL 60208, USA
| | - Ji-Ping Wang
- Department of Statistics, Northwestern University, Evanston, IL 60208, USA.
| | - Xiaozhong Wang
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
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Maksimov DA, Laktionov PP, Belyakin SN. Data analysis algorithm for DamID-seq profiling of chromatin proteins in Drosophila melanogaster. Chromosome Res 2016; 24:481-494. [DOI: 10.1007/s10577-016-9538-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 09/25/2016] [Accepted: 09/26/2016] [Indexed: 11/29/2022]
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49
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In silico identification of enhancers on the basis of a combination of transcription factor binding motif occurrences. Sci Rep 2016; 6:32476. [PMID: 27582178 PMCID: PMC5007594 DOI: 10.1038/srep32476] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 08/08/2016] [Indexed: 01/06/2023] Open
Abstract
Enhancers interact with gene promoters and form chromatin looping structures that serve important functions in various biological processes, such as the regulation of gene transcription and cell differentiation. However, enhancers are difficult to identify because they generally do not have fixed positions or consensus sequence features, and biological experiments for enhancer identification are costly in terms of labor and expense. In this work, several models were built by using various sequence-based feature sets and their combinations for enhancer prediction. The selected features derived from a recursive feature elimination method showed that the model using a combination of 141 transcription factor binding motif occurrences from 1,422 transcription factor position weight matrices achieved a favorably high prediction accuracy superior to that of other reported methods. The models demonstrated good prediction accuracy for different enhancer datasets obtained from different cell lines/tissues. In addition, prediction accuracy was further improved by integration of chromatin state features. Our method is complementary to wet-lab experimental methods and provides an additional method to identify enhancers.
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50
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MNase titration reveals differences between nucleosome occupancy and chromatin accessibility. Nat Commun 2016; 7:11485. [PMID: 27151365 PMCID: PMC4859066 DOI: 10.1038/ncomms11485] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 03/31/2016] [Indexed: 01/01/2023] Open
Abstract
Chromatin accessibility plays a fundamental role in gene regulation. Nucleosome placement, usually measured by quantifying protection of DNA from enzymatic digestion, can regulate accessibility. We introduce a metric that uses micrococcal nuclease (MNase) digestion in a novel manner to measure chromatin accessibility by combining information from several digests of increasing depths. This metric, MACC (MNase accessibility), quantifies the inherent heterogeneity of nucleosome accessibility in which some nucleosomes are seen preferentially at high MNase and some at low MNase. MACC interrogates each genomic locus, measuring both nucleosome location and accessibility in the same assay. MACC can be performed either with or without a histone immunoprecipitation step, and thereby compares histone and non-histone protection. We find that changes in accessibility at enhancers, promoters and other regulatory regions do not correlate with changes in nucleosome occupancy. Moreover, high nucleosome occupancy does not necessarily preclude high accessibility, which reveals novel principles of chromatin regulation.
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