1
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Jacob DR, Guiblet WM, Mamayusupova H, Shtumpf M, Ciuta I, Ruje L, Gretton S, Bikova M, Correa C, Dellow E, Agrawal SP, Shafiei N, Drobysevskaja A, Armstrong CM, Lam JDG, Vainshtein Y, Clarkson CT, Thorn GJ, Sohn K, Pradeepa MM, Chandrasekharan S, Brooke GN, Klenova E, Zhurkin VB, Teif VB. Nucleosome reorganisation in breast cancer tissues. Clin Epigenetics 2024; 16:50. [PMID: 38561804 PMCID: PMC10986098 DOI: 10.1186/s13148-024-01656-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 03/11/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Nucleosome repositioning in cancer is believed to cause many changes in genome organisation and gene expression. Understanding these changes is important to elucidate fundamental aspects of cancer. It is also important for medical diagnostics based on cell-free DNA (cfDNA), which originates from genomic DNA regions protected from digestion by nucleosomes. RESULTS We have generated high-resolution nucleosome maps in paired tumour and normal tissues from the same breast cancer patients using MNase-assisted histone H3 ChIP-seq and compared them with the corresponding cfDNA from blood plasma. This analysis has detected single-nucleosome repositioning at key regulatory regions in a patient-specific manner and common cancer-specific patterns across patients. The nucleosomes gained in tumour versus normal tissue were particularly informative of cancer pathways, with ~ 20-fold enrichment at CpG islands, a large fraction of which marked promoters of genes encoding DNA-binding proteins. The tumour tissues were characterised by a 5-10 bp decrease in the average distance between nucleosomes (nucleosome repeat length, NRL), which is qualitatively similar to the differences between pluripotent and differentiated cells. This effect was correlated with gene activity, differential DNA methylation and changes in local occupancy of linker histone variants H1.4 and H1X. CONCLUSIONS Our study offers a novel resource of high-resolution nucleosome maps in breast cancer patients and reports for the first time the effect of systematic decrease of NRL in paired tumour versus normal breast tissues from the same patient. Our findings provide a new mechanistic understanding of nucleosome repositioning in tumour tissues that can be valuable for patient diagnostics, stratification and monitoring.
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Affiliation(s)
- Divya R Jacob
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Wilfried M Guiblet
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Hulkar Mamayusupova
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Mariya Shtumpf
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Isabella Ciuta
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Luminita Ruje
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Svetlana Gretton
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
- School of Engineering, Arts, Science and Technology, University of Suffolk, James Hehir Building, University Avenue, Ipswich, Suffolk, IP3 0FS, UK
| | - Milena Bikova
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Clark Correa
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Emily Dellow
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Shivam P Agrawal
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Navid Shafiei
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | | | - Chris M Armstrong
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Jonathan D G Lam
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Yevhen Vainshtein
- Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB, Nobelstraße 12, 70569, Stuttgart, Germany
| | - Christopher T Clarkson
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
- University College London, Gower St, Bloomsbury, London, WC1E 6BT, UK
| | - Graeme J Thorn
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
- Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - Kai Sohn
- Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB, Nobelstraße 12, 70569, Stuttgart, Germany
| | - Madapura M Pradeepa
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK
| | - Sankaran Chandrasekharan
- Colchester General Hospital, East Suffolk and North Essex NHS Foundation Trust, Turner Road, Colchester, CO4 5JL, UK
| | - Greg N Brooke
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Elena Klenova
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Victor B Zhurkin
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Vladimir B Teif
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK.
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2
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Wilkinson AL, Zorzan I, Rugg-Gunn PJ. Epigenetic regulation of early human embryo development. Cell Stem Cell 2023; 30:1569-1584. [PMID: 37858333 DOI: 10.1016/j.stem.2023.09.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/18/2023] [Accepted: 09/25/2023] [Indexed: 10/21/2023]
Abstract
Studies of mammalian development have advanced our understanding of the genetic, epigenetic, and cellular processes that orchestrate embryogenesis and have uncovered new insights into the unique aspects of human embryogenesis. Recent studies have now produced the first epigenetic maps of early human embryogenesis, stimulating new ideas about epigenetic reprogramming, cell fate control, and the potential mechanisms underpinning developmental plasticity in human embryos. In this review, we discuss these new insights into the epigenetic regulation of early human development and the importance of these processes for safeguarding development. We also highlight unanswered questions and key challenges that remain to be addressed.
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Affiliation(s)
| | - Irene Zorzan
- Epigenetics Programme, Babraham Institute, Cambridge, UK
| | - Peter J Rugg-Gunn
- Epigenetics Programme, Babraham Institute, Cambridge, UK; Centre for Trophoblast Research, University of Cambridge, Cambridge, UK; Wellcome-MRC Cambridge Stem Cell Institute, Cambridge, UK.
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3
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Li S, Peng Y, Panchenko AR. DNA methylation: Precise modulation of chromatin structure and dynamics. Curr Opin Struct Biol 2022; 75:102430. [PMID: 35914496 DOI: 10.1016/j.sbi.2022.102430] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/06/2022] [Accepted: 06/16/2022] [Indexed: 11/19/2022]
Abstract
DNA methylation plays a vital role in epigenetic regulation in both plants and animals, and typically occurs at the 5-carbon position of the cytosine pyrimidine ring within the CpG dinucleotide steps. Cytosine methylation can alter DNA's geometry, mechanical and physico-chemical properties - thus influencing the molecular signaling events vital for transcription, replication and chromatin remodeling. Despite the profound effect cytosine methylation can have on DNA, the underlying atomistic mechanisms remain enigmatic. Many studies so far have produced controversial findings on how cytosine methylation dictates DNA flexibility and accessibility, nucleosome stability and dynamics. Here, we review the most recent experimental and computational studies that provide precise characterization of structure and function of cytosine methylation and its versatile roles in modulating DNA mechanics, nucleosome and chromatin structure, stability and dynamics. Moreover, the review briefly discusses the relationship between DNA methylation and nucleosome positioning, and the crosstalk between DNA methylation and histone tail modifications.
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Affiliation(s)
- Shuxiang Li
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, ON, Canada
| | - Yunhui Peng
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Anna R Panchenko
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, ON, Canada.
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4
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Oveisi M, Shukla M, Seymen N, Ohno M, Taniguchi Y, Nahata S, Loos R, Mufti GJ, Allshire RC, Dimitrov S, Karimi MM. iNucs: Inter-Nucleosome Interactions. Bioinformatics 2021; 37:4562-4563. [PMID: 34623394 PMCID: PMC8652021 DOI: 10.1093/bioinformatics/btab698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 09/29/2021] [Accepted: 10/05/2021] [Indexed: 11/24/2022] Open
Abstract
MOTIVATION Deciphering nucleosome-nucleosome interactions is an important step towards mesoscale description of chromatin organization but computational tools to perform such analyses are not publicly available. RESULTS We developed iNucs, a user-friendly and efficient Python-based bioinformatics tool to compute and visualize nucleosome resolved interactions using standard pairs format input generated from pairtools. AVAILABILITY https://github.com/Karimi-Lab/inucs/. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Mehrdad Oveisi
- Comprehensive Cancer Centre, School of Cancer & Pharmaceutical Sciences, Faculty of Life Sciences & Medicine, King’s College London, London SE5 8AF, UK
| | - Manu Shukla
- Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Nogayhan Seymen
- Comprehensive Cancer Centre, School of Cancer & Pharmaceutical Sciences, Faculty of Life Sciences & Medicine, King’s College London, London SE5 8AF, UK
| | - Masae Ohno
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan,Laboratory for Cell Systems Control, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka 565-0874, Japan
| | - Yuichi Taniguchi
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan,Laboratory for Cell Systems Control, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka 565-0874, Japan
| | - Sunil Nahata
- Institute for Advanced Biosciences, Inserm U 1209, CNRS UMR 5309, Université Grenoble Alpes, 38000 Grenoble, France
| | - Remco Loos
- BMS Center for Innovation and Translational Research Europe (CITRE, a Bristol Myers Squibb Company), Pabellón de Italia, 41092 Sevilla, Spain
| | - Ghulam J Mufti
- Comprehensive Cancer Centre, School of Cancer & Pharmaceutical Sciences, Faculty of Life Sciences & Medicine, King’s College London, London SE5 8AF, UK
| | - Robin C Allshire
- Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Stefan Dimitrov
- Institute for Advanced Biosciences, Inserm U 1209, CNRS UMR 5309, Université Grenoble Alpes, 38000 Grenoble, France,Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Balçova, Izmir 35330, Turkey
| | - Mohammad M Karimi
- Comprehensive Cancer Centre, School of Cancer & Pharmaceutical Sciences, Faculty of Life Sciences & Medicine, King’s College London, London SE5 8AF, UK,To whom correspondence should be addressed.
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5
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Fang K, Li T, Huang Y, Jin VX. NucHMM: a method for quantitative modeling of nucleosome organization identifying functional nucleosome states distinctly associated with splicing potentiality. Genome Biol 2021; 22:250. [PMID: 34446075 PMCID: PMC8390234 DOI: 10.1186/s13059-021-02465-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 08/12/2021] [Indexed: 01/01/2023] Open
Abstract
We develop a novel computational method, NucHMM, to identify functional nucleosome states associated with cell type-specific combinatorial histone marks and nucleosome organization features such as phasing, spacing and positioning. We test it on publicly available MNase-seq and ChIP-seq data in MCF7, H1, and IMR90 cells and identify 11 distinct functional nucleosome states. We demonstrate these nucleosome states are distinctly associated with the splicing potentiality of skipping exons. This advances our understanding of the chromatin function at the nucleosome level and offers insights into the interplay between nucleosome organization and splicing processes.
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Affiliation(s)
- Kun Fang
- Department of Molecular Medicine, UTHSA-UTSA Joint Biomedical Engineering Program, San Antonio, TX, 78229, USA
| | - Tianbao Li
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Yufei Huang
- Department of Medicine, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA, 15232, USA
| | - Victor X Jin
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA.
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6
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Chawla A, Nagy C, Turecki G. Chromatin Profiling Techniques: Exploring the Chromatin Environment and Its Contributions to Complex Traits. Int J Mol Sci 2021; 22:7612. [PMID: 34299232 PMCID: PMC8305586 DOI: 10.3390/ijms22147612] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 01/04/2023] Open
Abstract
The genetic architecture of complex traits is multifactorial. Genome-wide association studies (GWASs) have identified risk loci for complex traits and diseases that are disproportionately located at the non-coding regions of the genome. On the other hand, we have just begun to understand the regulatory roles of the non-coding genome, making it challenging to precisely interpret the functions of non-coding variants associated with complex diseases. Additionally, the epigenome plays an active role in mediating cellular responses to fluctuations of sensory or environmental stimuli. However, it remains unclear how exactly non-coding elements associate with epigenetic modifications to regulate gene expression changes and mediate phenotypic outcomes. Therefore, finer interrogations of the human epigenomic landscape in associating with non-coding variants are warranted. Recently, chromatin-profiling techniques have vastly improved our understanding of the numerous functions mediated by the epigenome and DNA structure. Here, we review various chromatin-profiling techniques, such as assays of chromatin accessibility, nucleosome distribution, histone modifications, and chromatin topology, and discuss their applications in unraveling the brain epigenome and etiology of complex traits at tissue homogenate and single-cell resolution. These techniques have elucidated compositional and structural organizing principles of the chromatin environment. Taken together, we believe that high-resolution epigenomic and DNA structure profiling will be one of the best ways to elucidate how non-coding genetic variations impact complex diseases, ultimately allowing us to pinpoint cell-type targets with therapeutic potential.
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Affiliation(s)
- Anjali Chawla
- Integrated Program in Neuroscience, McGill University, 845 Sherbrooke St W, Montreal, QC H3A 0G4, Canada;
- McGill Group for Suicide Studies, Department of Psychiatry, Douglas Mental Health University Institute, McGill University, 6875 LaSalle Blvd, Verdun, QC H4H 1R3, Canada;
| | - Corina Nagy
- McGill Group for Suicide Studies, Department of Psychiatry, Douglas Mental Health University Institute, McGill University, 6875 LaSalle Blvd, Verdun, QC H4H 1R3, Canada;
- Genome Quebec Innovation Centre, Department of Human Genetics, McGill University, 845 Sherbrooke St W, Montreal, QC H3A 0G4, Canada
| | - Gustavo Turecki
- Integrated Program in Neuroscience, McGill University, 845 Sherbrooke St W, Montreal, QC H3A 0G4, Canada;
- McGill Group for Suicide Studies, Department of Psychiatry, Douglas Mental Health University Institute, McGill University, 6875 LaSalle Blvd, Verdun, QC H4H 1R3, Canada;
- Genome Quebec Innovation Centre, Department of Human Genetics, McGill University, 845 Sherbrooke St W, Montreal, QC H3A 0G4, Canada
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7
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Larke MSC, Schwessinger R, Nojima T, Telenius J, Beagrie RA, Downes DJ, Oudelaar AM, Truch J, Graham B, Bender MA, Proudfoot NJ, Higgs DR, Hughes JR. Enhancers predominantly regulate gene expression during differentiation via transcription initiation. Mol Cell 2021; 81:983-997.e7. [PMID: 33539786 PMCID: PMC7612206 DOI: 10.1016/j.molcel.2021.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 09/25/2020] [Accepted: 01/02/2021] [Indexed: 12/16/2022]
Abstract
Gene transcription occurs via a cycle of linked events, including initiation, promoter-proximal pausing, and elongation of RNA polymerase II (Pol II). A key question is how transcriptional enhancers influence these events to control gene expression. Here, we present an approach that evaluates the level and change in promoter-proximal transcription (initiation and pausing) in the context of differential gene expression, genome-wide. This combinatorial approach shows that in primary cells, control of gene expression during differentiation is achieved predominantly via changes in transcription initiation rather than via release of Pol II pausing. Using genetically engineered mouse models, deleted for functionally validated enhancers of the α- and β-globin loci, we confirm that these elements regulate Pol II recruitment and/or initiation to modulate gene expression. Together, our data show that gene expression during differentiation is regulated predominantly at the level of initiation and that enhancers are key effectors of this process.
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Affiliation(s)
- Martin S C Larke
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Ron Schwessinger
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Takayuki Nojima
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Jelena Telenius
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Robert A Beagrie
- Laboratory of Gene Regulation, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Damien J Downes
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - A Marieke Oudelaar
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Julia Truch
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Bryony Graham
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - M A Bender
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Nicholas J Proudfoot
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Douglas R Higgs
- Laboratory of Gene Regulation, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
| | - Jim R Hughes
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
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8
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Chen H, Liang H. A High-Resolution Map of Human Enhancer RNA Loci Characterizes Super-enhancer Activities in Cancer. Cancer Cell 2020; 38:701-715.e5. [PMID: 33007258 PMCID: PMC7658066 DOI: 10.1016/j.ccell.2020.08.020] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 07/21/2020] [Accepted: 08/28/2020] [Indexed: 12/20/2022]
Abstract
Although enhancers play critical roles in cancer, quantifying enhancer activities in clinical samples remains challenging, especially for super-enhancers. Enhancer activities can be inferred from enhancer RNA (eRNA) signals, which requires enhancer transcription loci definition. Only a small proportion of human eRNA loci has been precisely identified, limiting investigations of enhancer-mediated oncogenic mechanisms. Here, we characterize super-enhancer regions using aggregated RNA sequencing (RNA-seq) data from large cohorts. Super-enhancers usually contain discrete loci featuring sharp eRNA expression peaks. We identify >300,000 eRNA loci in ∼377 Mb super-enhancer regions that are regulated by evolutionarily conserved, well-positioned nucleosomes and are frequently dysregulated in cancer. The eRNAs provide explanatory power for cancer phenotypes beyond that provided by mRNA expression through resolving intratumoral heterogeneity with enhancer cell-type specificity. Our study provides a high-resolution map of eRNA loci through which super-enhancer activities can be quantified by RNA-seq and a user-friendly data portal, enabling a broad range of biomedical investigations.
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Affiliation(s)
- Han Chen
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Han Liang
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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9
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Li S, Zheng EB, Zhao L, Liu S. Nonreciprocal and Conditional Cooperativity Directs the Pioneer Activity of Pluripotency Transcription Factors. Cell Rep 2019; 28:2689-2703.e4. [PMID: 31484078 PMCID: PMC6750763 DOI: 10.1016/j.celrep.2019.07.103] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 05/24/2019] [Accepted: 07/26/2019] [Indexed: 01/02/2023] Open
Abstract
Cooperative binding of transcription factors (TFs) to chromatin orchestrates gene expression programming and cell fate specification. However, the biophysical principles of TF cooperativity remain incompletely understood. Here we use single-molecule fluorescence microscopy to study the partnership between Sox2 and Oct4, two core members of the pluripotency gene regulatory network. We find that the ability of Sox2 to target DNA inside nucleosomes is strongly affected by the translational and rotational positioning of its binding motif. In contrast, Oct4 can access nucleosomal sites with equal capacities. Furthermore, the Sox2-Oct4 pair displays nonreciprocal cooperativity, with Oct4 modulating interaction of Sox2 with the nucleosome but not vice versa. Such cooperativity is conditional upon the composite motif's residing at specific nucleosomal locations. These results reveal that pioneer factors possess distinct chromatin-binding properties and suggest that the same set of TFs can differentially regulate gene activities on the basis of their motif positions in the nucleosomal context.
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Affiliation(s)
- Sai Li
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY 10065, USA
| | - Eric Bo Zheng
- Laboratory of Evolutionary Genetics and Genomics, The Rockefeller University, New York, NY 10065, USA
| | - Li Zhao
- Laboratory of Evolutionary Genetics and Genomics, The Rockefeller University, New York, NY 10065, USA
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY 10065, USA.
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10
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Tan HK, Wu CS, Li J, Tan ZH, Hoffman JR, Fry CJ, Yang H, Di Ruscio A, Tenen DG. DNMT3B shapes the mCA landscape and regulates mCG for promoter bivalency in human embryonic stem cells. Nucleic Acids Res 2019; 47:7460-7475. [PMID: 31219573 PMCID: PMC6698669 DOI: 10.1093/nar/gkz520] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 05/30/2019] [Accepted: 06/17/2019] [Indexed: 12/30/2022] Open
Abstract
DNMT3B is known as a de novo DNA methyltransferase. However, its preferential target sites for DNA methylation are largely unknown. Our analysis on ChIP-seq experiment in human embryonic stem cells (hESC) revealed that DNMT3B, mCA and H3K36me3 share the same genomic distribution profile. Deletion of DNMT3B or its histone-interacting domain (PWWP) demolished mCA in hESCs, suggesting that PWWP domain of DNMT3B directs the formation of mCA landscape. In contrast to the common presumption that PWWP guides DNMT3B-mediated mCG deposition, we found that deleting PWWP does not affect the mCG landscape. Nonetheless, DNMT3B knockout led to the formation of 2985 de novo hypomethylated regions at annotated promoter sites. Upon knockout, most of these promoters gain the bivalent marks, H3K4me3 and H3K27me3. We call them spurious bivalent promoters. Gene ontology analysis associated spurious bivalent promoters with development and cell differentiation. Overall, we found the importance of DNMT3B for shaping the mCA landscape and for maintaining the fidelity of the bivalent promoters in hESCs.
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Affiliation(s)
- Hong Kee Tan
- Cancer Science Institute of Singapore, National University of Singapore, 14 Medical Drive, #12-01, Singapore 117599
- National University of Singapore Graduate School for Integrative Sciences and Engineering, 21 Lower Kent Ridge, Singapore 119077
| | - Chan-Shuo Wu
- Cancer Science Institute of Singapore, National University of Singapore, 14 Medical Drive, #12-01, Singapore 117599
| | - Jia Li
- Cancer Science Institute of Singapore, National University of Singapore, 14 Medical Drive, #12-01, Singapore 117599
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Zi Hui Tan
- Cancer Science Institute of Singapore, National University of Singapore, 14 Medical Drive, #12-01, Singapore 117599
| | | | | | - Henry Yang
- Cancer Science Institute of Singapore, National University of Singapore, 14 Medical Drive, #12-01, Singapore 117599
| | - Annalisa Di Ruscio
- Department of Translational Medicine, University of Eastern Piedmont, Novara, NO 28100, Italy
- Harvard Stem Cell Institute, Boston, MA 02115, USA
| | - Daniel G Tenen
- Cancer Science Institute of Singapore, National University of Singapore, 14 Medical Drive, #12-01, Singapore 117599
- Harvard Stem Cell Institute, Boston, MA 02115, USA
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11
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Tellier M, Chalmers R. Human SETMAR is a DNA sequence-specific histone-methylase with a broad effect on the transcriptome. Nucleic Acids Res 2019; 47:122-133. [PMID: 30329085 PMCID: PMC6326780 DOI: 10.1093/nar/gky937] [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: 07/30/2018] [Accepted: 10/12/2018] [Indexed: 12/26/2022] Open
Abstract
Transposons impart dynamism to the genomes they inhabit and their movements frequently rewire the control of nearby genes. Occasionally, their proteins are domesticated when they evolve a new function. SETMAR is a protein methylase with a sequence-specific DNA binding domain. It began to evolve about 50 million years ago when an Hsmar1 transposon integrated downstream of a SET-domain methylase gene. Here we show that the DNA-binding domain of the transposase targets the enzyme to transposon-end remnants and that this is capable of regulating gene expression, dependent on the methylase activity. When SETMAR was modestly overexpressed in human cells, almost 1500 genes changed expression by more than 2-fold (65% up- and 35% down-regulated). These genes were enriched for the KEGG Pathways in Cancer and include several transcription factors important for development and differentiation. Expression of a similar level of a methylase-deficient SETMAR changed the expression of many fewer genes, 77% of which were down-regulated with no significant enrichment of KEGG Pathways. Our data is consistent with a model in which SETMAR is part of an anthropoid primate-specific regulatory network centered on the subset of genes containing a transposon end.
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Affiliation(s)
- Michael Tellier
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Ronald Chalmers
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
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12
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Mitochondrial Akt Signaling Modulated Reprogramming of Somatic Cells. Sci Rep 2019; 9:9919. [PMID: 31289326 PMCID: PMC6616364 DOI: 10.1038/s41598-019-46359-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 06/27/2019] [Indexed: 12/13/2022] Open
Abstract
The signaling mechanisms controlling somatic cell reprogramming are not fully understood. In this study, we report a novel role for mitochondrial Akt1 signaling that enhanced somatic cell reprogramming efficiency. The role of mitochondrial Akt1 in somatic cell reprogramming was investigated by transducing fibroblasts with the four reprogramming factors (Oct4, Sox2, Klf4, c-Myc) in conjunction with Mito-Akt1, Mito-dnAkt1, or control virus. Mito-Akt1 enhanced reprogramming efficiency whereas Mito-dnAkt1 inhibited reprogramming. The resulting iPSCs formed embryoid bodies in vitro and teratomas in vivo. Moreover, Oct4 and Nanog promoter methylation was reduced in the iPSCs generated in the presence of Mito-Akt1. Akt1 was activated and translocated into mitochondria after growth factor stimulation in embryonic stem cells (ESCs). To study the effect of mitochondrial Akt in ESCs, a mitochondria-targeting constitutively active Akt1 (Mito-Akt1) was expressed in ESCs. Gene expression profiling showed upregulation of genes that promote stem cell proliferation and survival and down-regulation of genes that promote differentiation. Analysis of cellular respiration indicated similar metabolic profile in the resulting iPSCs and ESCs, suggesting comparable bioenergetics. These findings showed that activation of mitochondrial Akt1 signaling was required during somatic cell reprogramming.
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13
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Hazelbaker DZ, Beccard A, Bara AM, Dabkowski N, Messana A, Mazzucato P, Lam D, Manning D, Eggan K, Barrett LE. A Scaled Framework for CRISPR Editing of Human Pluripotent Stem Cells to Study Psychiatric Disease. Stem Cell Reports 2018; 9:1315-1327. [PMID: 29020615 PMCID: PMC5639480 DOI: 10.1016/j.stemcr.2017.09.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 12/22/2022] Open
Abstract
Scaling of CRISPR-Cas9 technology in human pluripotent stem cells (hPSCs) represents an important step for modeling complex disease and developing drug screens in human cells. However, variables affecting the scaling efficiency of gene editing in hPSCs remain poorly understood. Here, we report a standardized CRISPR-Cas9 approach, with robust benchmarking at each step, to successfully target and genotype a set of psychiatric disease-implicated genes in hPSCs and provide a resource of edited hPSC lines for six of these genes. We found that transcriptional state and nucleosome positioning around targeted loci was not correlated with editing efficiency. However, editing frequencies varied between different hPSC lines and correlated with genomic stability, underscoring the need for careful cell line selection and unbiased assessments of genomic integrity. Together, our step-by-step quantification and in-depth analyses provide an experimental roadmap for scaling Cas9-mediated editing in hPSCs to study psychiatric disease, with broader applicability for other polygenic diseases.
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Affiliation(s)
- Dane Z Hazelbaker
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Amanda Beccard
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Anne M Bara
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Nicole Dabkowski
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Angelica Messana
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Patrizia Mazzucato
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Daisy Lam
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Danielle Manning
- Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Kevin Eggan
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA.
| | - Lindy E Barrett
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA.
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14
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Lövkvist C, Sneppen K, Haerter JO. Exploring the Link between Nucleosome Occupancy and DNA Methylation. Front Genet 2018; 8:232. [PMID: 29379519 PMCID: PMC5771128 DOI: 10.3389/fgene.2017.00232] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/22/2017] [Indexed: 12/21/2022] Open
Abstract
Near promoters, both nucleosomes and CpG sites form characteristic spatial patterns. Previously, nucleosome depleted regions were observed upstream of transcription start sites and nucleosome occupancy was reported to correlate both with CpG density and the level of CpG methylation. Several studies imply a causal link where CpG methylation might induce nucleosome formation, whereas others argue the opposite, i.e., that nucleosome occupancy might influence CpG methylation. Correlations are indeed evident between nucleosomes, CpG density and CpG methylation—at least near promoter sites. It is however less established whether there is an immediate causal relation between nucleosome occupancy and the presence of CpG sites—or if nucleosome occupancy could be influenced by other factors. In this work, we test for such causality in human genomes by analyzing the three quantities both near and away from promoter sites. For data from the human genome we compare promoter regions with given CpG densities with genomic regions without promoters but of similar CpG densities. We find the observed correlation between nucleosome occupancy and CpG density, respectively CpG methylation, to be specific to promoter regions. In other regions along the genome nucleosome occupancy is statistically independent of the positioning of CpGs or their methylation levels. Anti-correlation between CpG density and methylation level is however similarly strong in both regions. On promoters, nucleosome occupancy is more strongly affected by the level of gene expression than CpG density or CpG methylation—calling into question any direct causal relation between nucleosome occupancy and CpG organization. Rather, our results suggest that for organisms with cytosine methylation nucleosome occupancy might be primarily linked to gene expression, with no strong impact on methylation.
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Affiliation(s)
- Cecilia Lövkvist
- Center for Models of Life, Niels Bohr Institue, University of Copenhagen, Copenhagen, Denmark
| | - Kim Sneppen
- Center for Models of Life, Niels Bohr Institue, University of Copenhagen, Copenhagen, Denmark
| | - Jan O Haerter
- Center for Models of Life, Niels Bohr Institue, University of Copenhagen, Copenhagen, Denmark
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15
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Wang Y, van Merwyk L, Tönsing K, Walhorn V, Anselmetti D, Fernàndez-Busquets X. Biophysical characterization of the association of histones with single-stranded DNA. Biochim Biophys Acta Gen Subj 2017; 1861:2739-2749. [PMID: 28756274 DOI: 10.1016/j.bbagen.2017.07.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 07/19/2017] [Accepted: 07/24/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND Despite the profound current knowledge of the architecture and dynamics of nucleosomes, little is known about the structures generated by the interaction of histones with single-stranded DNA (ssDNA), which is widely present during replication and transcription. METHODS Non-denaturing gel electrophoresis, transmission electron microscopy, atomic force microscopy, magnetic tweezers. RESULTS Histones have a high affinity for ssDNA in 0.15M NaCl ionic strength, with an apparent binding constant similar to that calculated for their association with double-stranded DNA (dsDNA). The length of DNA (number of nucleotides in ssDNA or base pairs in dsDNA) associated with a fixed core histone mass is the same for both ssDNA and dsDNA. Although histone-ssDNA complexes show a high tendency to aggregate, nucleosome-like structures are formed at physiological salt concentrations. Core histones are able to protect ssDNA from digestion by micrococcal nuclease, and a shortening of ssDNA occurs upon its interaction with histones. The purified (+) strand of a cloned DNA fragment of nucleosomal origin has a higher affinity for histones than the purified complementary (-) strand. CONCLUSIONS At physiological ionic strength histones have high affinity for ssDNA, possibly associating with it into nucleosome-like structures. GENERAL SIGNIFICANCE In the cell nucleus histones may spontaneously interact with ssDNA to facilitate their participation in the replication and transcription of chromatin.
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Affiliation(s)
- Ying Wang
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics, Bielefeld University, Bielefeld 33615, Germany
| | - Luis van Merwyk
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics, Bielefeld University, Bielefeld 33615, Germany
| | - Katja Tönsing
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics, Bielefeld University, Bielefeld 33615, Germany
| | - Volker Walhorn
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics, Bielefeld University, Bielefeld 33615, Germany
| | - Dario Anselmetti
- Experimental Biophysics and Applied Nanoscience, Faculty of Physics, Bielefeld University, Bielefeld 33615, Germany
| | - Xavier Fernàndez-Busquets
- Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, Barcelona 08028, Spain; Barcelona Institute for Global Health (ISGlobal), Barcelona Center for International Health Research (CRESIB, Hospital Clínic-Universitat de Barcelona), Rosselló 149-153, Barcelona 08036, Spain; Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, Barcelona 08028, Spain.
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16
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A comparison of nucleosome organization in Drosophila cell lines. PLoS One 2017; 12:e0178590. [PMID: 28570602 PMCID: PMC5453549 DOI: 10.1371/journal.pone.0178590] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 05/16/2017] [Indexed: 01/25/2023] Open
Abstract
Changes in the distribution of nucleosomes along the genome influence chromatin structure and impact gene expression by modulating the accessibility of DNA to transcriptional machinery. However, the role of genome-wide nucleosome positioning in gene expression and in maintaining differentiated cell states remains poorly understood. Drosophila melanogaster cell lines represent distinct tissue types and exhibit cell-type specific gene expression profiles. They thus could provide a useful tool for investigating cell-type specific nucleosome organization of an organism's genome. To evaluate this possibility, we compared genome-wide nucleosome positioning and occupancy in five different Drosophila tissue-specific cell lines, and in reconstituted chromatin, and then tested for correlations between nucleosome positioning, transcription factor binding motifs, and gene expression. Nucleosomes in all cell lines were positioned in accordance with previously known DNA-nucleosome interactions, with helically repeating A/T di-nucleotide pairs arranged within nucleosomal DNAs and AT-rich pentamers generally excluded from nucleosomal DNA. Nucleosome organization in all cell lines differed markedly from in vitro reconstituted chromatin, with highly expressed genes showing strong nucleosome organization around transcriptional start sites. Importantly, comparative analysis identified genomic regions that exhibited cell line-specific nucleosome enrichment or depletion. Further analysis of these regions identified 91 out of 16,384 possible heptamer sequences that showed differential nucleosomal occupation between cell lines, and 49 of the heptamers matched one or more known transcription factor binding sites. These results demonstrate that there is differential nucleosome positioning between these Drosophila cell lines and therefore identify a system that could be used to investigate the functional significance of differential nucleosomal positioning in cell type specification.
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17
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Rondelet G, Dal Maso T, Willems L, Wouters J. Structural basis for recognition of histone H3K36me3 nucleosome by human de novo DNA methyltransferases 3A and 3B. J Struct Biol 2016; 194:357-67. [PMID: 26993463 DOI: 10.1016/j.jsb.2016.03.013] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 03/14/2016] [Accepted: 03/15/2016] [Indexed: 01/01/2023]
Abstract
DNA methylation is an important epigenetic modification involved in chromatin organization and gene expression. The function of DNA methylation depends on cell context and is correlated with histone modification patterns. In particular, trimethylation of Lys36 on histone H3 tail (H3K36me3) is associated with DNA methylation and elongation phase of transcription. PWWP domains of the de novo DNA methyltransferases DNMT3A and DNMT3B read this epigenetic mark to guide DNA methylation. Here we report the first crystal structure of the DNMT3B PWWP domain-H3K36me3 complex. Based on this structure, we propose a model of the DNMT3A PWWP domain-H3K36me3 complex and build a model of DNMT3A (PWWP-ADD-CD) in a nucleosomal context. The trimethylated side chain of Lys36 (H3K36me3) is inserted into an aromatic cage similar to the "Royal" superfamily domains known to bind methylated histones. A key interaction between trimethylated Lys36 and a conserved water molecule stabilized by Ser270 explains the lack of affinity of mutated DNMT3B (S270P) for the H3K36me3 epigenetic mark in the ICF (Immunodeficiency, Centromeric instability and Facial abnormalities) syndrome. The model of the DNMT3A-DNMT3L heterotetramer in complex with a dinucleosome highlights the mechanism for recognition of nucleosome by DNMT3s and explains the periodicity of de novo DNA methylation.
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Affiliation(s)
- Grégoire Rondelet
- Department of Chemistry, University of Namur, 61 rue de Bruxelles, B-5000 Namur, Belgium.
| | - Thomas Dal Maso
- Department of Chemistry, University of Namur, 61 rue de Bruxelles, B-5000 Namur, Belgium
| | - Luc Willems
- Molecular and Cellular Epigenetics (GIGA) and Molecular Biology (Gembloux Agro-Bio Tech), University of Liège (ULg), 4000 Liège, Belgium
| | - Johan Wouters
- Department of Chemistry, University of Namur, 61 rue de Bruxelles, B-5000 Namur, Belgium
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18
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Ivanov M, Baranova A, Butler T, Spellman P, Mileyko V. Non-random fragmentation patterns in circulating cell-free DNA reflect epigenetic regulation. BMC Genomics 2015; 16 Suppl 13:S1. [PMID: 26693644 PMCID: PMC4686799 DOI: 10.1186/1471-2164-16-s13-s1] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The assessment of cell-free circulating DNA fragments, also known as a "liquid biopsy" of the patient's plasma, is an important source for the discovery and subsequent non-invasive monitoring of cancer and other pathological conditions. Although the nucleosome-guided fragmentation patterns of cell-free DNA (cfDNA) have not yet been studied in detail, non-random representation of cfDNA sequencies may reflect chromatin features in the tissue of origin at gene-regulation level. RESULTS In this study, we investigated the association between epigenetic landscapes of human tissues evident in the patterns of cfDNA in plasma by deep sequencing of human cfDNA samples. We have demonstrated that baseline characteristics of cfDNA fragmentation pattern are in concordance with the ones corresponding to cell lines-derived. To identify the loci differentially represented in cfDNA fragment, we mapped the transcription start sites within the sequenced cfDNA fragments and tested for association of these genomic coordinates with the relative strength and the patterns of gene expressions. Preselected sets of house-keeping and tissue specific genes were used as models for actively expressed and silenced genes. Developed measure of gene regulation was able to differentiate these two sets based on sequencing coverage near gene transcription start site. CONCLUSION Experimental outcomes suggest that cfDNA retains characteristics previously noted in genome-wide analysis of chromatin structure, in particular, in MNase-seq assays. Thus far the analysis of the DNA fragmentation pattern may aid further developing of cfDNA based biomarkers for a variety of human conditions.
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Affiliation(s)
- Maxim Ivanov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Prosp. Lavrentieva, 8, 630090, Novosibirsk, Russia
- Atlas Oncology Diagnostics, ltd, Moscow, 121069, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141700 Russia
| | - Ancha Baranova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Prosp. Lavrentieva, 8, 630090, Novosibirsk, Russia
- Atlas Oncology Diagnostics, ltd, Moscow, 121069, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141700 Russia
- Research Centre for Medical Genetics, Moscow, 115478, Russia
- School of Systems Biology, George Mason University, Fairfax, VA, 22030, USA
| | - Timothy Butler
- Knight Cancer Institute, Oregon Health & Sciences University, Portland, OR 97239, USA
- Department of Molecular and Medical Genetics, Oregon Health & Sciences University, Portland, OR 97239, USA
| | - Paul Spellman
- Knight Cancer Institute, Oregon Health & Sciences University, Portland, OR 97239, USA
- Department of Molecular and Medical Genetics, Oregon Health & Sciences University, Portland, OR 97239, USA
| | - Vladislav Mileyko
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Prosp. Lavrentieva, 8, 630090, Novosibirsk, Russia
- Atlas Oncology Diagnostics, ltd, Moscow, 121069, Russia
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Nakatani Y, Mello CC, Hashimoto SI, Shimada A, Nakamura R, Tsukahara T, Qu W, Yoshimura J, Suzuki Y, Sugano S, Takeda H, Fire A, Morishita S. Associations between nucleosome phasing, sequence asymmetry, and tissue-specific expression in a set of inbred Medaka species. BMC Genomics 2015; 16:978. [PMID: 26584643 PMCID: PMC4653950 DOI: 10.1186/s12864-015-2198-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/07/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Transcription start sites (TSSs) with pronounced and phased nucleosome arrays downstream and nucleosome-depleted regions upstream of TSSs are observed in various species. RESULTS We have characterized sequence variation and expression properties of this set of TSSs (which we call "Nucleocyclic TSSs") using germline and somatic cells of three medaka (Oryzias latipes) inbred isolates from different locations. We found nucleocyclic TSSs in medaka to be associated with higher gene expression and characterized by a clear boundary in sequence composition with potentially-nucleosome-destabilizing A/T-enrichment upstream (p < 10(-60)) and nucleosome- accommodating C/G-enrichment downstream (p < 10(-40)) that was highly conserved from an ancestor. A substantial genetic distance between the strains facilitated the in-depth analysis of patterns of fixed mutations, revealing a localization-specific equilibrium between the rates of distinct mutation categories that would serve to maintain the conserved sequence anisotropy around TSSs. Downstream of nucleocyclic TSSs, C to T, T to C, and other mutation rates on the sense strand increased around first nucleosome dyads and decreased around first linkers, which contrasted with genomewide mutational patterns around nucleosomes (p < 5 %). C to T rates are higher than G to A rates around nucleosome associated with germline nucleocyclic TSS sites (p < 5 %), potentially due to the asymmetric effect of transcription-coupled repair. CONCLUSIONS Our results demonstrate an atypical evolutionary process surrounding nucleocyclic TSSs.
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Affiliation(s)
- Yoichiro Nakatani
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-0882, Japan.
| | - Cecilia C Mello
- Department of Pathology, School of Medicine, Stanford University, Stanford, CA, 94305-5324, USA.
| | - Shin-Ichi Hashimoto
- Graduate School of Medical Sciences, Kanazawa University, Kanazawa, 920-1192, Japan.
| | - Atsuko Shimada
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan.
| | - Ryohei Nakamura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan.
| | - Tatsuya Tsukahara
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan.
| | - Wei Qu
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-0882, Japan.
| | - Jun Yoshimura
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-0882, Japan.
| | - Yutaka Suzuki
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, 108-8639, Japan.
| | - Sumio Sugano
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, 108-8639, Japan.
| | - Hiroyuki Takeda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan.
| | - Andrew Fire
- Departments of Pathology and Genetics, School of Medicine, Stanford University, Stanford, CA, 94305-5324, USA.
| | - Shinichi Morishita
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-0882, Japan.
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