1
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Kondoh H. Enhancer Arrays Regulating Developmental Genes: Sox2 Enhancers as a Paradigm. Results Probl Cell Differ 2024; 72:145-166. [PMID: 38509257 DOI: 10.1007/978-3-031-39027-2_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
Enhancers are the primary regulatory DNA sequences in eukaryotes and are mostly located in the non-coding sequences of genes, namely, intergenic regions and introns. The essential characteristic of an enhancer is the ability to activate proximal genes, e.g., a reporter gene in a reporter assay, regardless of orientation, relative position, and distance from the gene. These characteristics are ascribed to the interaction (spatial proximity) of the enhancer sequence and the gene promoter via DNA looping, discussed in the latter part of this chapter.Developmentally regulated genes are associated with multiple enhancers carrying distinct cell and developmental stage specificities, which form arrays on the genome. We discuss the array of enhancers regulating the Sox2 gene as a paradigm. Sox2 enhancers are the best studied enhancers of a single gene in developmental regulation. In addition, the Sox2 gene is located in a genomic region with a very sparse gene distribution (no other protein-coding genes in ~1.6 Mb in the mouse genome), termed a "gene desert," which means that most identified enhancers in the region are associated with Sox2 regulation. Furthermore, the importance of the Sox2 gene in stem cell regulation and neural development justifies focusing on Sox2-associated enhancers.
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Affiliation(s)
- Hisato Kondoh
- Osaka University, Suita, Osaka, Japan
- Biohistory Research Hall, Takatsuki, Osaka, Japan
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2
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Voon HPJ, Hii L, Garvie A, Udugama M, Krug B, Russo C, Chüeh AC, Daly RJ, Morey A, Bell TDM, Turner SJ, Rosenbluh J, Daniel P, Firestein R, Mann JR, Collas P, Jabado N, Wong LH. Pediatric glioma histone H3.3 K27M/G34R mutations drive abnormalities in PML nuclear bodies. Genome Biol 2023; 24:284. [PMID: 38066546 PMCID: PMC10704828 DOI: 10.1186/s13059-023-03122-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 11/24/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Point mutations in histone variant H3.3 (H3.3K27M, H3.3G34R) and the H3.3-specific ATRX/DAXX chaperone complex are frequent events in pediatric gliomas. These H3.3 point mutations affect many chromatin modifications but the exact oncogenic mechanisms are currently unclear. Histone H3.3 is known to localize to nuclear compartments known as promyelocytic leukemia (PML) nuclear bodies, which are frequently mutated and confirmed as oncogenic drivers in acute promyelocytic leukemia. RESULTS We find that the pediatric glioma-associated H3.3 point mutations disrupt the formation of PML nuclear bodies and this prevents differentiation down glial lineages. Similar to leukemias driven by PML mutations, H3.3-mutated glioma cells are sensitive to drugs that target PML bodies. We also find that point mutations in IDH1/2-which are common events in adult gliomas and myeloid leukemias-also disrupt the formation of PML bodies. CONCLUSIONS We identify PML as a contributor to oncogenesis in a subset of gliomas and show that targeting PML bodies is effective in treating these H3.3-mutated pediatric gliomas.
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Affiliation(s)
- Hsiao P J Voon
- Cancer Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Linda Hii
- Cancer Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Andrew Garvie
- Cancer Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Maheshi Udugama
- Cancer Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Brian Krug
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Caterina Russo
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Anderly C Chüeh
- Cancer Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Roger J Daly
- Cancer Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Alison Morey
- Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Toby D M Bell
- School of Chemistry, Monash University, Clayton, VIC, Australia
| | - Stephen J Turner
- Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Joseph Rosenbluh
- Cancer Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Paul Daniel
- Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular and Translational Science, Monash University, Clayton, VIC, Australia
| | - Ron Firestein
- Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Molecular and Translational Science, Monash University, Clayton, VIC, Australia
| | - Jeffrey R Mann
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC, Australia
| | - Philippe Collas
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, 0317, Oslo, Norway
- Department of Immunology and Transfusion Medicine, Oslo University Hospital, 0424, Oslo, Norway
| | - Nada Jabado
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Division of Experimental Medicine, McGill University, Montreal, QC, Canada
- Department of Paediatrics, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Lee H Wong
- Cancer Program, Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Australia.
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3
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Kleinschmidt H, Xu C, Bai L. Using Synthetic DNA Libraries to Investigate Chromatin and Gene Regulation. Chromosoma 2023; 132:167-189. [PMID: 37184694 PMCID: PMC10542970 DOI: 10.1007/s00412-023-00796-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 05/16/2023]
Abstract
Despite the recent explosion in genome-wide studies in chromatin and gene regulation, we are still far from extracting a set of genetic rules that can predict the function of the regulatory genome. One major reason for this deficiency is that gene regulation is a multi-layered process that involves an enormous variable space, which cannot be fully explored using native genomes. This problem can be partially solved by introducing synthetic DNA libraries into cells, a method that can test the regulatory roles of thousands to millions of sequences with limited variables. Here, we review recent applications of this method to study transcription factor (TF) binding, nucleosome positioning, and transcriptional activity. We discuss the design principles, experimental procedures, and major findings from these studies and compare the pros and cons of different approaches.
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Affiliation(s)
- Holly Kleinschmidt
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Cheng Xu
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Lu Bai
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA.
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4
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Taylor T, Sikorska N, Shchuka VM, Chahar S, Ji C, Macpherson NN, Moorthy SD, de Kort MAC, Mullany S, Khader N, Gillespie ZE, Langroudi L, Tobias IC, Lenstra TL, Mitchell JA, Sexton T. Transcriptional regulation and chromatin architecture maintenance are decoupled functions at the Sox2 locus. Genes Dev 2022; 36:699-717. [PMID: 35710138 PMCID: PMC9296009 DOI: 10.1101/gad.349489.122] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/03/2022] [Indexed: 11/24/2022]
Abstract
How distal regulatory elements control gene transcription and chromatin topology is not clearly defined, yet these processes are closely linked in lineage specification during development. Through allele-specific genome editing and chromatin interaction analyses of the Sox2 locus in mouse embryonic stem cells, we found a striking disconnection between transcriptional control and chromatin architecture. We traced nearly all Sox2 transcriptional activation to a small number of key transcription factor binding sites, whose deletions have no effect on promoter-enhancer interaction frequencies or topological domain organization. Local chromatin architecture maintenance, including at the topologically associating domain (TAD) boundary downstream from the Sox2 enhancer, is widely distributed over multiple transcription factor-bound regions and maintained in a CTCF-independent manner. Furthermore, partial disruption of promoter-enhancer interactions by ectopic chromatin loop formation has no effect on Sox2 transcription. These findings indicate that many transcription factors are involved in modulating chromatin architecture independently of CTCF.
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Affiliation(s)
- Tiegh Taylor
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M55 3G5, Canada
| | - Natalia Sikorska
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), UMR7104, Centre National de la Recherche Scientifique, U1258, Institut National de la Santé et de la Recherche Médicale, University of Strasbourg, 6704 Illkirch, France
| | - Virlana M Shchuka
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M55 3G5, Canada
| | - Sanjay Chahar
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), UMR7104, Centre National de la Recherche Scientifique, U1258, Institut National de la Santé et de la Recherche Médicale, University of Strasbourg, 6704 Illkirch, France
| | - Chenfan Ji
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M55 3G5, Canada
| | - Neil N Macpherson
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M55 3G5, Canada
| | - Sakthi D Moorthy
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M55 3G5, Canada
| | - Marit A C de Kort
- Division of Gene Regulation, the Netherlands Cancer Institute, Oncode Institute, 1066CX Amsterdam, the Netherlands
| | - Shanelle Mullany
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M55 3G5, Canada
| | - Nawrah Khader
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M55 3G5, Canada
| | - Zoe E Gillespie
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M55 3G5, Canada
| | - Lida Langroudi
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M55 3G5, Canada
| | - Ian C Tobias
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M55 3G5, Canada
| | - Tineke L Lenstra
- Division of Gene Regulation, the Netherlands Cancer Institute, Oncode Institute, 1066CX Amsterdam, the Netherlands
| | - Jennifer A Mitchell
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M55 3G5, Canada
| | - Tom Sexton
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), UMR7104, Centre National de la Recherche Scientifique, U1258, Institut National de la Santé et de la Recherche Médicale, University of Strasbourg, 6704 Illkirch, France
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5
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Panara V, Monteiro R, Koltowska K. Epigenetic Regulation of Endothelial Cell Lineages During Zebrafish Development-New Insights From Technical Advances. Front Cell Dev Biol 2022; 10:891538. [PMID: 35615697 PMCID: PMC9125237 DOI: 10.3389/fcell.2022.891538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 04/10/2022] [Indexed: 01/09/2023] Open
Abstract
Epigenetic regulation is integral in orchestrating the spatiotemporal regulation of gene expression which underlies tissue development. The emergence of new tools to assess genome-wide epigenetic modifications has enabled significant advances in the field of vascular biology in zebrafish. Zebrafish represents a powerful model to investigate the activity of cis-regulatory elements in vivo by combining technologies such as ATAC-seq, ChIP-seq and CUT&Tag with the generation of transgenic lines and live imaging to validate the activity of these regulatory elements. Recently, this approach led to the identification and characterization of key enhancers of important vascular genes, such as gata2a, notch1b and dll4. In this review we will discuss how the latest technologies in epigenetics are being used in the zebrafish to determine chromatin states and assess the function of the cis-regulatory sequences that shape the zebrafish vascular network.
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Affiliation(s)
- Virginia Panara
- Immunology Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Rui Monteiro
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom,Birmingham Centre of Genome Biology, University of Birmingham, Birmingham, United Kingdom
| | - Katarzyna Koltowska
- Immunology Genetics and Pathology, Uppsala University, Uppsala, Sweden,*Correspondence: Katarzyna Koltowska,
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6
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Maldotti M, Lauria A, Anselmi F, Molineris I, Tamburrini A, Meng G, Polignano IL, Scrivano MG, Campestre F, Simon LM, Rapelli S, Morandi E, Incarnato D, Oliviero S. The acetyltransferase p300 is recruited in trans to multiple enhancer sites by lncSmad7. Nucleic Acids Res 2022; 50:2587-2602. [PMID: 35137201 PMCID: PMC8934626 DOI: 10.1093/nar/gkac083] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/23/2022] [Accepted: 01/25/2022] [Indexed: 12/13/2022] Open
Abstract
The histone acetyltransferase p300 (also known as KAT3B) is a general transcriptional coactivator that introduces the H3K27ac mark on enhancers triggering their activation and gene transcription. Genome-wide screenings demonstrated that a large fraction of long non-coding RNAs (lncRNAs) plays a role in cellular processes and organ development although the underlying molecular mechanisms remain largely unclear (1,2). We found 122 lncRNAs that interacts directly with p300. In depth analysis of one of these, lncSmad7, is required to maintain ESC self-renewal and it interacts to the C-terminal domain of p300. lncSmad7 also contains predicted RNA-DNA Hoogsteen forming base pairing. Combined Chromatin Isolation by RNA precipitation followed by sequencing (ChIRP-seq) together with CRISPR/Cas9 mutagenesis of the target sites demonstrate that lncSmad7 binds and recruits p300 to enhancers in trans, to trigger enhancer acetylation and transcriptional activation of its target genes. Thus, these results unveil a new mechanism by which p300 is recruited to the genome.
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Affiliation(s)
- Mara Maldotti
- Dipartimento di Scienze della Vita e Biologia dei Sistemi and MBC, Università di Torino, Via Nizza 52, 10126 Torino, Italy.,Italian Institute for Genomic Medicine (IIGM), Sp142 Km 3.95, 10060 Candiolo (Torino), Italy
| | - Andrea Lauria
- Dipartimento di Scienze della Vita e Biologia dei Sistemi and MBC, Università di Torino, Via Nizza 52, 10126 Torino, Italy.,Italian Institute for Genomic Medicine (IIGM), Sp142 Km 3.95, 10060 Candiolo (Torino), Italy
| | - Francesca Anselmi
- Dipartimento di Scienze della Vita e Biologia dei Sistemi and MBC, Università di Torino, Via Nizza 52, 10126 Torino, Italy.,Italian Institute for Genomic Medicine (IIGM), Sp142 Km 3.95, 10060 Candiolo (Torino), Italy
| | - Ivan Molineris
- Dipartimento di Scienze della Vita e Biologia dei Sistemi and MBC, Università di Torino, Via Nizza 52, 10126 Torino, Italy.,Italian Institute for Genomic Medicine (IIGM), Sp142 Km 3.95, 10060 Candiolo (Torino), Italy
| | - Annalaura Tamburrini
- Dipartimento di Scienze della Vita e Biologia dei Sistemi and MBC, Università di Torino, Via Nizza 52, 10126 Torino, Italy.,Italian Institute for Genomic Medicine (IIGM), Sp142 Km 3.95, 10060 Candiolo (Torino), Italy
| | - Guohua Meng
- Dipartimento di Scienze della Vita e Biologia dei Sistemi and MBC, Università di Torino, Via Nizza 52, 10126 Torino, Italy.,Italian Institute for Genomic Medicine (IIGM), Sp142 Km 3.95, 10060 Candiolo (Torino), Italy
| | - Isabelle Laurence Polignano
- Dipartimento di Scienze della Vita e Biologia dei Sistemi and MBC, Università di Torino, Via Nizza 52, 10126 Torino, Italy.,Italian Institute for Genomic Medicine (IIGM), Sp142 Km 3.95, 10060 Candiolo (Torino), Italy
| | - Mirko Giuseppe Scrivano
- Dipartimento di Scienze della Vita e Biologia dei Sistemi and MBC, Università di Torino, Via Nizza 52, 10126 Torino, Italy
| | - Fabiola Campestre
- Dipartimento di Scienze della Vita e Biologia dei Sistemi and MBC, Università di Torino, Via Nizza 52, 10126 Torino, Italy
| | - Lisa Marie Simon
- Dipartimento di Scienze della Vita e Biologia dei Sistemi and MBC, Università di Torino, Via Nizza 52, 10126 Torino, Italy
| | - Stefania Rapelli
- Dipartimento di Scienze della Vita e Biologia dei Sistemi and MBC, Università di Torino, Via Nizza 52, 10126 Torino, Italy.,Italian Institute for Genomic Medicine (IIGM), Sp142 Km 3.95, 10060 Candiolo (Torino), Italy
| | - Edoardo Morandi
- Dipartimento di Scienze della Vita e Biologia dei Sistemi and MBC, Università di Torino, Via Nizza 52, 10126 Torino, Italy
| | - Danny Incarnato
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Salvatore Oliviero
- Dipartimento di Scienze della Vita e Biologia dei Sistemi and MBC, Università di Torino, Via Nizza 52, 10126 Torino, Italy.,Italian Institute for Genomic Medicine (IIGM), Sp142 Km 3.95, 10060 Candiolo (Torino), Italy
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7
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Singh G, Mullany S, Moorthy SD, Zhang R, Mehdi T, Tian R, Duncan AG, Moses AM, Mitchell JA. A flexible repertoire of transcription factor binding sites and a diversity threshold determines enhancer activity in embryonic stem cells. Genome Res 2021; 31:564-575. [PMID: 33712417 PMCID: PMC8015845 DOI: 10.1101/gr.272468.120] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 02/19/2021] [Indexed: 12/28/2022]
Abstract
Transcriptional enhancers are critical for development and phenotype evolution and are often mutated in disease contexts; however, even in well-studied cell types, the sequence code conferring enhancer activity remains unknown. To examine the enhancer regulatory code for pluripotent stem cells, we identified genomic regions with conserved binding of multiple transcription factors in mouse and human embryonic stem cells (ESCs). Examination of these regions revealed that they contain on average 12.6 conserved transcription factor binding site (TFBS) sequences. Enriched TFBSs are a diverse repertoire of 70 different sequences representing the binding sequences of both known and novel ESC regulators. Using a diverse set of TFBSs from this repertoire was sufficient to construct short synthetic enhancers with activity comparable to native enhancers. Site-directed mutagenesis of conserved TFBSs in endogenous enhancers or TFBS deletion from synthetic sequences revealed a requirement for 10 or more different TFBSs. Furthermore, specific TFBSs, including the POU5F1:SOX2 comotif, are dispensable, despite cobinding the POU5F1 (also known as OCT4), SOX2, and NANOG master regulators of pluripotency. These findings reveal that a TFBS sequence diversity threshold overrides the need for optimized regulatory grammar and individual TFBSs that recruit specific master regulators.
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Affiliation(s)
- Gurdeep Singh
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada
| | - Shanelle Mullany
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada
| | - Sakthi D Moorthy
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada
| | - Richard Zhang
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada
| | - Tahmid Mehdi
- Department of Computer Science, University of Toronto, Toronto, M5S 2E4, Canada
| | - Ruxiao Tian
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada
| | - Andrew G Duncan
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada
| | - Alan M Moses
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada.,Department of Computer Science, University of Toronto, Toronto, M5S 2E4, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, M5S 3B3, Canada
| | - Jennifer A Mitchell
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada
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8
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Wang HF, Warrier T, Farran CA, Zheng ZH, Xing QR, Fullwood MJ, Zhang LF, Li H, Xu J, Lim TM, Loh YH. Defining Essential Enhancers for Pluripotent Stem Cells Using a Features-Oriented CRISPR-Cas9 Screen. Cell Rep 2020; 33:108309. [PMID: 33113365 DOI: 10.1016/j.celrep.2020.108309] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/23/2020] [Accepted: 10/05/2020] [Indexed: 12/26/2022] Open
Abstract
cis-regulatory elements (CREs) regulate the expression of genes in their genomic neighborhoods and influence cellular processes such as cell-fate maintenance and differentiation. To date, there remain major gaps in the functional characterization of CREs and the identification of their target genes in the cellular native environment. In this study, we perform a features-oriented CRISPR-utilized systematic (FOCUS) screen of OCT4-bound CREs using CRISPR-Cas9 to identify functional enhancers important for pluripotency maintenance in mESCs. From the initial 235 candidates tested, 16 CREs are identified to be essential stem cell enhancers. Using RNA-seq and genomic 4C-seq, we further uncover a complex network of candidate CREs and their downstream target genes, which supports the growth and self-renewal of mESCs. Notably, an essential enhancer, CRE111, and its target, Lrrc31, form the important switch to modulate the LIF-JAK1-STAT3 signaling pathway.
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Affiliation(s)
- Hao Fei Wang
- Laboratory for Epigenetics, Stem Cells and Cell Therapy, Programme in Stem Cell, Regenerative Medicine and Aging, A(∗)STAR Institute of Molecular and Cell Biology, Singapore 138673, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Tushar Warrier
- Laboratory for Epigenetics, Stem Cells and Cell Therapy, Programme in Stem Cell, Regenerative Medicine and Aging, A(∗)STAR Institute of Molecular and Cell Biology, Singapore 138673, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Chadi A Farran
- Laboratory for Epigenetics, Stem Cells and Cell Therapy, Programme in Stem Cell, Regenerative Medicine and Aging, A(∗)STAR Institute of Molecular and Cell Biology, Singapore 138673, Singapore
| | - Zi Hao Zheng
- Laboratory for Epigenetics, Stem Cells and Cell Therapy, Programme in Stem Cell, Regenerative Medicine and Aging, A(∗)STAR Institute of Molecular and Cell Biology, Singapore 138673, Singapore
| | - Qiao Rui Xing
- Laboratory for Epigenetics, Stem Cells and Cell Therapy, Programme in Stem Cell, Regenerative Medicine and Aging, A(∗)STAR Institute of Molecular and Cell Biology, Singapore 138673, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Melissa J Fullwood
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Li-Feng Zhang
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Hu Li
- Center for Individualized Medicine, Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA
| | - Jian Xu
- Department of Biological Sciences and Centre for BioImaging Sciences, National University of Singapore, Singapore 117543, Singapore; Department of Plant Systems Physiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, the Netherlands.
| | - Tit-Meng Lim
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
| | - Yuin-Han Loh
- Laboratory for Epigenetics, Stem Cells and Cell Therapy, Programme in Stem Cell, Regenerative Medicine and Aging, A(∗)STAR Institute of Molecular and Cell Biology, Singapore 138673, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore; Department of Physiology, NUS Yong Loo Lin School of Medicine, 2 Medical Drive, MD9, Singapore 117593, Singapore.
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9
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Tobias IC, Abatti LE, Moorthy SD, Mullany S, Taylor T, Khader N, Filice MA, Mitchell JA. Transcriptional enhancers: from prediction to functional assessment on a genome-wide scale. Genome 2020; 64:426-448. [PMID: 32961076 DOI: 10.1139/gen-2020-0104] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Enhancers are cis-regulatory sequences located distally to target genes. These sequences consolidate developmental and environmental cues to coordinate gene expression in a tissue-specific manner. Enhancer function and tissue specificity depend on the expressed set of transcription factors, which recognize binding sites and recruit cofactors that regulate local chromatin organization and gene transcription. Unlike other genomic elements, enhancers are challenging to identify because they function independently of orientation, are often distant from their promoters, have poorly defined boundaries, and display no reading frame. In addition, there are no defined genetic or epigenetic features that are unambiguously associated with enhancer activity. Over recent years there have been developments in both empirical assays and computational methods for enhancer prediction. We review genome-wide tools, CRISPR advancements, and high-throughput screening approaches that have improved our ability to both observe and manipulate enhancers in vitro at the level of primary genetic sequences, chromatin states, and spatial interactions. We also highlight contemporary animal models and their importance to enhancer validation. Together, these experimental systems and techniques complement one another and broaden our understanding of enhancer function in development, evolution, and disease.
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Affiliation(s)
- Ian C Tobias
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Luis E Abatti
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Sakthi D Moorthy
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Shanelle Mullany
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Tiegh Taylor
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Nawrah Khader
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Mario A Filice
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
| | - Jennifer A Mitchell
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3G5, Canada
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10
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Cucco F, Sarogni P, Rossato S, Alpa M, Patimo A, Latorre A, Magnani C, Puisac B, Ramos FJ, Pié J, Musio A. Pathogenic variants in EP300 and ANKRD11 in patients with phenotypes overlapping Cornelia de Lange syndrome. Am J Med Genet A 2020; 182:1690-1696. [PMID: 32476269 DOI: 10.1002/ajmg.a.61611] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/20/2020] [Accepted: 04/20/2020] [Indexed: 12/22/2022]
Abstract
Cornelia de Lange syndrome (CdLS), Rubinstein-Taybi syndrome (RSTS), and KBG syndrome are three distinct developmental human disorders. Variants in seven genes belonging to the cohesin pathway, NIPBL, SMC1A, SMC3, HDAC8, RAD21, ANKRD11, and BRD4, were identified in about 80% of patients with CdLS, suggesting that additional causative genes remain to be discovered. Two genes, CREBBP and EP300, have been associated with RSTS, whereas KBG results from variants in ANKRD11. By exome sequencing, a genetic cause was elucidated in two patients with clinical diagnosis of CdLS but without variants in known CdLS genes. In particular, genetic variants in EP300 and ANKRD11 were identified in the two patients with CdLS. EP300 and ANKRD11 pathogenic variants caused the reduction of the respective proteins suggesting that their low levels contribute to CdLS-like phenotype. These findings highlight the clinical overlap between CdLS, RSTS, and KBG and support the notion that these rare disorders are linked to abnormal chromatin remodeling, which in turn affects the transcriptional machinery.
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Affiliation(s)
- Francesco Cucco
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Pisa, Italy
| | - Patrizia Sarogni
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Pisa, Italy
| | - Sara Rossato
- U.O.C. Pediatria, Ospedale San Bortolo, Vicenza, Italy
| | - Mirella Alpa
- Department of Clinical and Biological Sciences, Center of Research of Immunopathology and Rare Diseases, Coordinating Center of the Network for Rare Diseases of Piedmont and Aosta Valley, Turin, Italy
| | - Alessandra Patimo
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Pisa, Italy
| | - Ana Latorre
- Departamento de Farmacología-Fisiología y Departamento de Pediatría, Hospital Clínico Universitario "Lozano Blesa", Facultad de Medicina, Universidad de Zaragoza, ISS-Aragon and CIBERER-GCV02, Unidad de Genética Clínica y Genómica Funcional, Zaragoza, Spain
| | - Cinzia Magnani
- Neonatology and Neonatal Intensive Care Unit, Maternal and Child Department, University of Parma, Parma, Italy
| | - Beatriz Puisac
- Departamento de Farmacología-Fisiología y Departamento de Pediatría, Hospital Clínico Universitario "Lozano Blesa", Facultad de Medicina, Universidad de Zaragoza, ISS-Aragon and CIBERER-GCV02, Unidad de Genética Clínica y Genómica Funcional, Zaragoza, Spain
| | - Feliciano J Ramos
- Departamento de Farmacología-Fisiología y Departamento de Pediatría, Hospital Clínico Universitario "Lozano Blesa", Facultad de Medicina, Universidad de Zaragoza, ISS-Aragon and CIBERER-GCV02, Unidad de Genética Clínica y Genómica Funcional, Zaragoza, Spain
| | - Juan Pié
- Departamento de Farmacología-Fisiología y Departamento de Pediatría, Hospital Clínico Universitario "Lozano Blesa", Facultad de Medicina, Universidad de Zaragoza, ISS-Aragon and CIBERER-GCV02, Unidad de Genética Clínica y Genómica Funcional, Zaragoza, Spain
| | - Antonio Musio
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Pisa, Italy
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11
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Kurihara M, Kato K, Sanbo C, Shigenobu S, Ohkawa Y, Fuchigami T, Miyanari Y. Genomic Profiling by ALaP-Seq Reveals Transcriptional Regulation by PML Bodies through DNMT3A Exclusion. Mol Cell 2020; 78:493-505.e8. [PMID: 32353257 DOI: 10.1016/j.molcel.2020.04.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 12/06/2019] [Accepted: 04/02/2020] [Indexed: 12/22/2022]
Abstract
The promyelocytic leukemia (PML) body is a phase-separated nuclear structure physically associated with chromatin, implying its crucial roles in genome functions. However, its role in transcriptional regulation is largely unknown. We developed APEX-mediated chromatin labeling and purification (ALaP) to identify the genomic regions proximal to PML bodies. We found that PML bodies associate with active regulatory regions across the genome and with ∼300 kb of the short arm of the Y chromosome (YS300) in mouse embryonic stem cells. The PML body association with YS300 is essential for the transcriptional activity of the neighboring Y-linked clustered genes. Mechanistically, PML bodies provide specific nuclear spaces that the de novo DNA methyltransferase DNMT3A cannot access, resulting in the steady maintenance of a hypo-methylated state at Y-linked gene promoters. Our study underscores a new mechanism for gene regulation in the 3D nuclear space and provides insights into the functional properties of nuclear structures for genome function.
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Affiliation(s)
- Misuzu Kurihara
- Exploratory Research Center on Life and Living Systems (ExCELLS), Okazaki, 444-8787, Japan; National Institute for Basic Biology (NIBB), Okazaki, 444-8787, Japan
| | - Kagayaki Kato
- Exploratory Research Center on Life and Living Systems (ExCELLS), Okazaki, 444-8787, Japan; National Institute for Basic Biology (NIBB), Okazaki, 444-8787, Japan; Center for Novel Science Initiatives (CNSI), National Institutes of Natural Sciences (NINS), Okazaki, 444-8787, Japan
| | - Chiaki Sanbo
- Exploratory Research Center on Life and Living Systems (ExCELLS), Okazaki, 444-8787, Japan; National Institute for Basic Biology (NIBB), Okazaki, 444-8787, Japan
| | - Shuji Shigenobu
- National Institute for Basic Biology (NIBB), Okazaki, 444-8787, Japan; Department of Basic Biology, School of Life Science, SOKENDAI, Hayama, 240-0193, Japan
| | - Yasuyuki Ohkawa
- Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-0054, Japan
| | - Takeshi Fuchigami
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, 852-8521, Japan
| | - Yusuke Miyanari
- Exploratory Research Center on Life and Living Systems (ExCELLS), Okazaki, 444-8787, Japan; National Institute for Basic Biology (NIBB), Okazaki, 444-8787, Japan; Department of Basic Biology, School of Life Science, SOKENDAI, Hayama, 240-0193, Japan.
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12
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King DM, Hong CKY, Shepherdson JL, Granas DM, Maricque BB, Cohen BA. Synthetic and genomic regulatory elements reveal aspects of cis-regulatory grammar in mouse embryonic stem cells. eLife 2020; 9:41279. [PMID: 32043966 PMCID: PMC7077988 DOI: 10.7554/elife.41279] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 02/07/2020] [Indexed: 01/08/2023] Open
Abstract
In embryonic stem cells (ESCs), a core transcription factor (TF) network establishes the gene expression program necessary for pluripotency. To address how interactions between four key TFs contribute to cis-regulation in mouse ESCs, we assayed two massively parallel reporter assay (MPRA) libraries composed of binding sites for SOX2, POU5F1 (OCT4), KLF4, and ESRRB. Comparisons between synthetic cis-regulatory elements and genomic sequences with comparable binding site configurations revealed some aspects of a regulatory grammar. The expression of synthetic elements is influenced by both the number and arrangement of binding sites. This grammar plays only a small role for genomic sequences, as the relative activities of genomic sequences are best explained by the predicted occupancy of binding sites, regardless of binding site identity and positioning. Our results suggest that the effects of transcription factor binding sites (TFBS) are influenced by the order and orientation of sites, but that in the genome the overall occupancy of TFs is the primary determinant of activity. Transcription factors are proteins that flip genetic switches; their role is to control when and where genes are active. They do this by binding to short stretches of DNA called cis-regulatory sequences. Each sequence can have several binding sites for different transcription factors, but it is largely unclear whether the transcription factors binding to the same regulatory sequence actually work together. It is possible that each transcription factor may work independently and there only needs to be critical mass of transcription factors bound to throw the genetic switch. If this is the case, the most important features of a cis-regulatory sequence should be the number of binding sites it contains, and how tightly the transcription factors bind to those sites. The more transcription factors and the more strongly they bind, the more active the gene should be. An alternative option is that certain transcription factors may work better together, enhancing each other's effects such that the total effect is more than the sum of its parts. If this is true, the order, orientation and spacing of the binding sites within a sequence should matter more than the number. One way to investigate to distinguish between these possibilities is to study mouse embryonic stem cells, which have a core set of four transcription factors. Looking directly at a real genome, however, can be confusing and it is difficult to measure the effects of different cis-regulatory sequences because genes differ in so many other ways. To tackle this problem, King et al. created a synthetic set of cis-regulatory sequences based on the four core transcription factors found in mouse stem cells. The synthetic set had every combination of two, three or four of the binding sites, with each site either facing forwards or backwards along the DNA strand. King et al. attached each of the synthetic cis-regulatory sequences to a reporter gene to find out how well each sequence performed. This revealed that the cis-regulatory sequences with the most binding sites and the tightest binding affinities work best, suggesting that transcription factors mainly work independently. There was evidence of some interaction between some transcription factors, because, of the synthetic sequences with four binding sites, some worked better than others, and there were patterns in the most effective binding site combinations. However, these effects were small and when King et al. went on to test sequences from the real mouse genome, the most important factor by far was the number of binding sites. Synthetic libraries of DNA sequences allow researchers to examine gene regulation more clearly than is possible in real genomes. Yet this approach does have its limitations and it is impossible to capture every type of cis-regulatory sequence in one library. The next step to extend this work is to combine the two approaches, taking sequences from the real genome and manipulating them one by one. This could help to unravel the rules that govern how cis-regulatory sequences work in real cells.
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Affiliation(s)
- Dana M King
- Edison Center for Genome Sciences and Systems Biology, Washington University in St. Louis, St. Louis, United States.,Department of Genetics, Washington University in St. Louis, St. Louis, United States
| | - Clarice Kit Yee Hong
- Edison Center for Genome Sciences and Systems Biology, Washington University in St. Louis, St. Louis, United States.,Department of Genetics, Washington University in St. Louis, St. Louis, United States
| | - James L Shepherdson
- Edison Center for Genome Sciences and Systems Biology, Washington University in St. Louis, St. Louis, United States.,Department of Genetics, Washington University in St. Louis, St. Louis, United States
| | - David M Granas
- Edison Center for Genome Sciences and Systems Biology, Washington University in St. Louis, St. Louis, United States.,Department of Genetics, Washington University in St. Louis, St. Louis, United States
| | - Brett B Maricque
- Edison Center for Genome Sciences and Systems Biology, Washington University in St. Louis, St. Louis, United States.,Department of Genetics, Washington University in St. Louis, St. Louis, United States
| | - Barak A Cohen
- Edison Center for Genome Sciences and Systems Biology, Washington University in St. Louis, St. Louis, United States.,Department of Genetics, Washington University in St. Louis, St. Louis, United States
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13
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Avagliano L, Parenti I, Grazioli P, Di Fede E, Parodi C, Mariani M, Kaiser FJ, Selicorni A, Gervasini C, Massa V. Chromatinopathies: A focus on Cornelia de Lange syndrome. Clin Genet 2020; 97:3-11. [PMID: 31721174 DOI: 10.1111/cge.13674] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 10/22/2019] [Accepted: 10/24/2019] [Indexed: 01/01/2023]
Abstract
In recent years, many genes have been associated with chromatinopathies classified as "Cornelia de Lange Syndrome-like." It is known that the phenotype of these patients becomes less recognizable, overlapping to features characteristic of other syndromes caused by genetic variants affecting different regulators of chromatin structure and function. Therefore, Cornelia de Lange syndrome diagnosis might be arduous due to the seldom discordance between unexpected molecular diagnosis and clinical evaluation. Here, we review the molecular features of Cornelia de Lange syndrome, supporting the hypothesis that "CdLS-like syndromes" are part of a larger "rare disease family" sharing multiple clinical features and common disrupted molecular pathways.
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Affiliation(s)
- Laura Avagliano
- Department of Health Sciences, Università degli Studi di Milano, Milano, Italy
| | - Ilaria Parenti
- Section for Functional Genetics, Institute of Human Genetics, University of Lübeck, Lübeck, Germany
- Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria
| | - Paolo Grazioli
- Department of Health Sciences, Università degli Studi di Milano, Milano, Italy
| | - Elisabetta Di Fede
- Department of Health Sciences, Università degli Studi di Milano, Milano, Italy
| | - Chiara Parodi
- Department of Health Sciences, Università degli Studi di Milano, Milano, Italy
| | | | - Frank J Kaiser
- Section for Functional Genetics, Institute of Human Genetics, University of Lübeck, Lübeck, Germany
- DZHK e.V. (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany
| | | | - Cristina Gervasini
- Department of Health Sciences, Università degli Studi di Milano, Milano, Italy
| | - Valentina Massa
- Department of Health Sciences, Università degli Studi di Milano, Milano, Italy
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14
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Barron M, Zhang S, Li J. A sparse differential clustering algorithm for tracing cell type changes via single-cell RNA-sequencing data. Nucleic Acids Res 2019; 46:e14. [PMID: 29140455 PMCID: PMC5815159 DOI: 10.1093/nar/gkx1113] [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: 05/07/2017] [Accepted: 10/24/2017] [Indexed: 12/15/2022] Open
Abstract
Cell types in cell populations change as the condition changes: some cell types die out, new cell types may emerge and surviving cell types evolve to adapt to the new condition. Using single-cell RNA-sequencing data that measure the gene expression of cells before and after the condition change, we propose an algorithm, SparseDC, which identifies cell types, traces their changes across conditions and identifies genes which are marker genes for these changes. By solving a unified optimization problem, SparseDC completes all three tasks simultaneously. SparseDC is highly computationally efficient and demonstrates its accuracy on both simulated and real data.
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Affiliation(s)
- Martin Barron
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Siyuan Zhang
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.,Mike and Josie Harper Cancer Research Institute, University of Notre Dame, IN 46617, USA
| | - Jun Li
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN 46556, USA.,Mike and Josie Harper Cancer Research Institute, University of Notre Dame, IN 46617, USA
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15
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Dhaliwal NK, Abatti LE, Mitchell JA. KLF4 protein stability regulated by interaction with pluripotency transcription factors overrides transcriptional control. Genes Dev 2019; 33:1069-1082. [PMID: 31221664 PMCID: PMC6672055 DOI: 10.1101/gad.324319.119] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 05/13/2019] [Indexed: 12/14/2022]
Abstract
Embryonic stem (ES) cells are regulated by a network of transcription factors that maintain the pluripotent state. Differentiation relies on down-regulation of pluripotency transcription factors disrupting this network. While investigating transcriptional regulation of the pluripotency transcription factor Kruppel-like factor 4 (Klf4), we observed that homozygous deletion of distal enhancers caused a 17-fold decrease in Klf4 transcript but surprisingly decreased protein levels by less than twofold, indicating that posttranscriptional control of KLF4 protein overrides transcriptional control. The lack of sensitivity of KLF4 to transcription is due to high protein stability (half-life >24 h). This stability is context-dependent and is disrupted during differentiation, as evidenced by a shift to a half-life of <2 h. KLF4 protein stability is maintained through interaction with other pluripotency transcription factors (NANOG, SOX2, and STAT3) that together facilitate association of KLF4 with RNA polymerase II. In addition, the KLF4 DNA-binding and transactivation domains are required for optimal KLF4 protein stability. Posttranslational modification of KLF4 destabilizes the protein as cells exit the pluripotent state, and mutations that prevent this destabilization also prevent differentiation. These data indicate that the core pluripotency transcription factors are integrated by posttranslational mechanisms to maintain the pluripotent state and identify mutations that increase KLF4 protein stability while maintaining transcription factor function.
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Affiliation(s)
- Navroop K Dhaliwal
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontaria M5S3G5, Canada
| | - Luis E Abatti
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontaria M5S3G5, Canada
| | - Jennifer A Mitchell
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontaria M5S3G5, Canada
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16
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Ben Zouari Y, Molitor AM, Sikorska N, Pancaldi V, Sexton T. ChiCMaxima: a robust and simple pipeline for detection and visualization of chromatin looping in Capture Hi-C. Genome Biol 2019; 20:102. [PMID: 31118054 PMCID: PMC6532271 DOI: 10.1186/s13059-019-1706-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 05/03/2019] [Indexed: 12/19/2022] Open
Abstract
Capture Hi-C (CHi-C) is a new technique for assessing genome organization based on chromosome conformation capture coupled to oligonucleotide capture of regions of interest, such as gene promoters. Chromatin loop detection is challenging because existing Hi-C/4C-like tools, which make different assumptions about the technical biases presented, are often unsuitable. We describe a new approach, ChiCMaxima, which uses local maxima combined with limited filtering to detect DNA looping interactions, integrating information from biological replicates. ChiCMaxima shows more stringency and robustness compared to previously developed tools. The tool includes a GUI browser for flexible visualization of CHi-C profiles alongside epigenomic tracks.
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Affiliation(s)
- Yousra Ben Zouari
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France
- CNRS UMR7104, Illkirch, France
- INSERM U1258, Illkirch, France
- University of Strasbourg, Illkirch, France
| | - Anne M Molitor
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France
- CNRS UMR7104, Illkirch, France
- INSERM U1258, Illkirch, France
- University of Strasbourg, Illkirch, France
| | - Natalia Sikorska
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France
- CNRS UMR7104, Illkirch, France
- INSERM U1258, Illkirch, France
- University of Strasbourg, Illkirch, France
| | - Vera Pancaldi
- Centre de Recherches en Cancérologie de Toulouse (CRCT), INSERM U1037, Toulouse, France
- University Paul Sabatier III, Toulouse, France
- Barcelona Supercomputing Center, Barcelona, Spain
| | - Tom Sexton
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France.
- CNRS UMR7104, Illkirch, France.
- INSERM U1258, Illkirch, France.
- University of Strasbourg, Illkirch, France.
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17
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Kumar R, Evans T. Activation-Induced Cytidine Deaminase Regulates Fibroblast Growth Factor/Extracellular Signal-Regulated Kinases Signaling to Achieve the Naïve Pluripotent State During Reprogramming. Stem Cells 2019; 37:1003-1017. [PMID: 31021461 PMCID: PMC6766926 DOI: 10.1002/stem.3023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 03/20/2019] [Accepted: 03/31/2019] [Indexed: 11/12/2022]
Abstract
Induced pluripotent stem cells (iPSCs) derived by in vitro reprogramming of somatic cells retain the capacity to self-renew and to differentiate into many cell types. Pluripotency encompasses multiple states, with naïve iPSCs considered as ground state, possessing high levels of self-renewal capacity and maximum potential without lineage restriction. We showed previously that activation-induced cytidine deaminase (AICDA) facilitates stabilization of pluripotency during reprogramming. Here, we report that Acida-/- iPSCs, even when successfully reprogrammed, fail to achieve the naïve pluripotent state and remain primed for differentiation because of a failure to suppress fibroblast growth factor (FGF)/extracellular signal-regulated kinases (ERK) signaling. Although the mutant cells display marked genomic hypermethylation, suppression of FGF/ERK signaling by AICDA is independent of deaminase activity. Thus, our study identifies AICDA as a novel regulator of naïve pluripotency through its activity on FGF/ERK signaling. Stem Cells 2019;37:1003-1017.
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Affiliation(s)
- Ritu Kumar
- Department of Surgery, Weill Cornell Medicine, New York, New York, USA
| | - Todd Evans
- Department of Surgery, Weill Cornell Medicine, New York, New York, USA
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18
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Gillespie ZE, Barkhshi T, Sosa Ponce ML, Georgel PT, Ausió J. 40th International Asilomar Chromatin, Chromosomes, and Epigenetics Conference. Biochem Cell Biol 2019; 97:777-782. [PMID: 30974061 DOI: 10.1139/bcb-2019-0054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The 40th International Asilomar Chromatin, Chromosomes, and Epigenetics Conference was held in the Asilomar Conference Grounds, Pacific Grove, California, USA, on 6-9 December 2018. The organizing committee consisted of established scientists in the fields of chromatin and epigenetics: Sally Pasion and Michael Goldman from the Biology Department, San Francisco State University, California, USA; Philippe Georgel from the Department of Biological Sciences, Marshal University, West Virginia, USA; Juan Ausió from the Department of Biochemistry and Microbiology, University of Victoria, British Columbia, Canada; and Christopher Eskiw from the Department of Biochemistry, University of Saskatchewan, Saskatchewan, Canada. The meeting had two keynote speakers: Jessica Tyler and Jennifer Mitchell, and it covered topics on transcription, replication and repair, epigenetics, cell differentiation and disease, telomeres, and centromeres and it had two sessions devoted to nuclear and genomic organization. It encompassed the enthusiastic presentations of excellent trainees within the breathtaking natural setting of Pacific Grove.
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Affiliation(s)
- Zoe E Gillespie
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.,Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Tanner Barkhshi
- Department of Biological Sciences, Marshall University, Huntington, WV 25755, USA.,Cell Differentiation and Development Center, Marshall University, Huntington, WV 25755, USA
| | - Maria Laura Sosa Ponce
- Departments of Biochemistry and Molecular Biology and Oncology, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Philippe T Georgel
- Department of Biological Sciences, Marshall University, Huntington, WV 25755, USA.,Cell Differentiation and Development Center, Marshall University, Huntington, WV 25755, USA
| | - Juan Ausió
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
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19
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Cheetham SW, Gruhn WH, van den Ameele J, Krautz R, Southall TD, Kobayashi T, Surani MA, Brand AH. Targeted DamID reveals differential binding of mammalian pluripotency factors. Development 2018; 145:dev.170209. [PMID: 30185410 DOI: 10.1242/dev.170209] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 08/23/2018] [Indexed: 12/14/2022]
Abstract
The precise control of gene expression by transcription factor networks is crucial to organismal development. The predominant approach for mapping transcription factor-chromatin interactions has been chromatin immunoprecipitation (ChIP). However, ChIP requires a large number of homogeneous cells and antisera with high specificity. A second approach, DamID, has the drawback that high levels of Dam methylase are toxic. Here, we modify our targeted DamID approach (TaDa) to enable cell type-specific expression in mammalian systems, generating an inducible system (mammalian TaDa or MaTaDa) to identify genome-wide protein/DNA interactions in 100 to 1000 times fewer cells than ChIP-based approaches. We mapped the binding sites of two key pluripotency factors, OCT4 and PRDM14, in mouse embryonic stem cells, epiblast-like cells and primordial germ cell-like cells (PGCLCs). PGCLCs are an important system for elucidating primordial germ cell development in mice. We monitored PRDM14 binding during the specification of PGCLCs, identifying direct targets of PRDM14 that are key to understanding its crucial role in PGCLC development. We show that MaTaDa is a sensitive and accurate method for assessing cell type-specific transcription factor binding in limited numbers of cells.
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Affiliation(s)
- Seth W Cheetham
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Wolfram H Gruhn
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Jelle van den Ameele
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Robert Krautz
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Tony D Southall
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Toshihiro Kobayashi
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - M Azim Surani
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Andrea H Brand
- The Gurdon Institute and Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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20
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Berrens RV, Andrews S, Spensberger D, Santos F, Dean W, Gould P, Sharif J, Olova N, Chandra T, Koseki H, von Meyenn F, Reik W. An endosiRNA-Based Repression Mechanism Counteracts Transposon Activation during Global DNA Demethylation in Embryonic Stem Cells. Cell Stem Cell 2018; 21:694-703.e7. [PMID: 29100015 PMCID: PMC5678422 DOI: 10.1016/j.stem.2017.10.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 08/14/2017] [Accepted: 10/12/2017] [Indexed: 12/28/2022]
Abstract
Erasure of DNA methylation and repressive chromatin marks in the mammalian germline leads to risk of transcriptional activation of transposable elements (TEs). Here, we used mouse embryonic stem cells (ESCs) to identify an endosiRNA-based mechanism involved in suppression of TE transcription. In ESCs with DNA demethylation induced by acute deletion of Dnmt1, we saw an increase in sense transcription at TEs, resulting in an abundance of sense/antisense transcripts leading to high levels of ARGONAUTE2 (AGO2)-bound small RNAs. Inhibition of Dicer or Ago2 expression revealed that small RNAs are involved in an immediate response to demethylation-induced transposon activation, while the deposition of repressive histone marks follows as a chronic response. In vivo, we also found TE-specific endosiRNAs present during primordial germ cell development. Our results suggest that antisense TE transcription is a “trap” that elicits an endosiRNA response to restrain acute transposon activity during epigenetic reprogramming in the mammalian germline. Global DNA demethylation in embryonic stem cells leads to transposon activation Transposon activation increases the abundance of sense/antisense transcripts ARGONAUTE2-bound endosiRNAs accumulate at high levels for acute repression Longer-term transposon repression depends on repressive histone marks
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Affiliation(s)
- Rebecca V Berrens
- Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, UK; University of Cambridge, The Old Schools, Trinity Lane, Cambridge CB2 1TN, UK.
| | - Simon Andrews
- Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, UK
| | | | - Fátima Santos
- Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, UK; University of Cambridge, The Old Schools, Trinity Lane, Cambridge CB2 1TN, UK
| | - Wendy Dean
- Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, UK
| | - Poppy Gould
- Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, UK
| | - Jafar Sharif
- RIKEN Research Center for Allergy and Immunology, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, 230-0045 Kanagawa, Japan
| | - Nelly Olova
- Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, UK
| | - Tamir Chandra
- Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, UK
| | - Haruhiko Koseki
- RIKEN Research Center for Allergy and Immunology, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, 230-0045 Kanagawa, Japan
| | | | - Wolf Reik
- Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, UK; University of Cambridge, The Old Schools, Trinity Lane, Cambridge CB2 1TN, UK; Wellcome Trust Sanger Institute, Hinxton CB10 1SA, UK.
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21
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Li Y, Shi W, Wasserman WW. Genome-wide prediction of cis-regulatory regions using supervised deep learning methods. BMC Bioinformatics 2018; 19:202. [PMID: 29855387 PMCID: PMC5984344 DOI: 10.1186/s12859-018-2187-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 05/04/2018] [Indexed: 01/07/2023] Open
Abstract
Background In the human genome, 98% of DNA sequences are non-protein-coding regions that were previously disregarded as junk DNA. In fact, non-coding regions host a variety of cis-regulatory regions which precisely control the expression of genes. Thus, Identifying active cis-regulatory regions in the human genome is critical for understanding gene regulation and assessing the impact of genetic variation on phenotype. The developments of high-throughput sequencing and machine learning technologies make it possible to predict cis-regulatory regions genome wide. Results Based on rich data resources such as the Encyclopedia of DNA Elements (ENCODE) and the Functional Annotation of the Mammalian Genome (FANTOM) projects, we introduce DECRES based on supervised deep learning approaches for the identification of enhancer and promoter regions in the human genome. Due to their ability to discover patterns in large and complex data, the introduction of deep learning methods enables a significant advance in our knowledge of the genomic locations of cis-regulatory regions. Using models for well-characterized cell lines, we identify key experimental features that contribute to the predictive performance. Applying DECRES, we delineate locations of 300,000 candidate enhancers genome wide (6.8% of the genome, of which 40,000 are supported by bidirectional transcription data), and 26,000 candidate promoters (0.6% of the genome). Conclusion The predicted annotations of cis-regulatory regions will provide broad utility for genome interpretation from functional genomics to clinical applications. The DECRES model demonstrates potentials of deep learning technologies when combined with high-throughput sequencing data, and inspires the development of other advanced neural network models for further improvement of genome annotations. Electronic supplementary material The online version of this article (10.1186/s12859-018-2187-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yifeng Li
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Rm 3109, 950 West 28th Avenue, Vancouver, V5Z 4H4, Canada.,Digital Technologies Research Centre, National Research Council Canada, Building M-50, 1200 Montreal Road, Ottawa, K1A 0R6, Canada
| | - Wenqiang Shi
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Rm 3109, 950 West 28th Avenue, Vancouver, V5Z 4H4, Canada
| | - Wyeth W Wasserman
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Rm 3109, 950 West 28th Avenue, Vancouver, V5Z 4H4, Canada.
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Dhaliwal NK, Miri K, Davidson S, Tamim El Jarkass H, Mitchell JA. KLF4 Nuclear Export Requires ERK Activation and Initiates Exit from Naive Pluripotency. Stem Cell Reports 2018; 10:1308-1323. [PMID: 29526737 PMCID: PMC6000723 DOI: 10.1016/j.stemcr.2018.02.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 02/09/2018] [Accepted: 02/12/2018] [Indexed: 01/27/2023] Open
Abstract
Cooperative action of a transcription factor complex containing OCT4, SOX2, NANOG, and KLF4 maintains the naive pluripotent state; however, less is known about the mechanisms that disrupt this complex, initiating exit from pluripotency. We show that, as embryonic stem cells (ESCs) exit pluripotency, KLF4 protein is exported from the nucleus causing rapid decline in Nanog and Klf4 transcription; as a result, KLF4 is the first pluripotency transcription factor removed from transcription-associated complexes during differentiation. KLF4 nuclear export requires ERK activation, and phosphorylation of KLF4 by ERK initiates interaction of KLF4 with nuclear export factor XPO1, leading to KLF4 export. Mutation of the ERK phosphorylation site in KLF4 (S132) blocks KLF4 nuclear export, the decline in Nanog, Klf4, and Sox2 mRNA, and differentiation. These findings demonstrate that relocalization of KLF4 to the cytoplasm is a critical first step in exit from the naive pluripotent state and initiation of ESC differentiation.
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Affiliation(s)
- Navroop K Dhaliwal
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Kamelia Miri
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Scott Davidson
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Hala Tamim El Jarkass
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Jennifer A Mitchell
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada; Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON M5S 3B2, Canada.
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23
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Nora EP, Goloborodko A, Valton AL, Gibcus JH, Uebersohn A, Abdennur N, Dekker J, Mirny LA, Bruneau BG. Targeted Degradation of CTCF Decouples Local Insulation of Chromosome Domains from Genomic Compartmentalization. Cell 2017; 169:930-944.e22. [PMID: 28525758 PMCID: PMC5538188 DOI: 10.1016/j.cell.2017.05.004] [Citation(s) in RCA: 1040] [Impact Index Per Article: 148.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/14/2017] [Accepted: 05/02/2017] [Indexed: 01/17/2023]
Abstract
The molecular mechanisms underlying folding of mammalian chromosomes remain poorly understood. The transcription factor CTCF is a candidate regulator of chromosomal structure. Using the auxin-inducible degron system in mouse embryonic stem cells, we show that CTCF is absolutely and dose-dependently required for looping between CTCF target sites and insulation of topologically associating domains (TADs). Restoring CTCF reinstates proper architecture on altered chromosomes, indicating a powerful instructive function for CTCF in chromatin folding. CTCF remains essential for TAD organization in non-dividing cells. Surprisingly, active and inactive genome compartments remain properly segregated upon CTCF depletion, revealing that compartmentalization of mammalian chromosomes emerges independently of proper insulation of TADs. Furthermore, our data support that CTCF mediates transcriptional insulator function through enhancer blocking but not as a direct barrier to heterochromatin spreading. Beyond defining the functions of CTCF in chromosome folding, these results provide new fundamental insights into the rules governing mammalian genome organization.
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Affiliation(s)
- Elphège P Nora
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158, USA; Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San Francisco, CA 94158, USA.
| | - Anton Goloborodko
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Anne-Laure Valton
- Howard Hughes Medical Institute, Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605-0103, USA
| | - Johan H Gibcus
- Howard Hughes Medical Institute, Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605-0103, USA
| | - Alec Uebersohn
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158, USA; Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San Francisco, CA 94158, USA
| | - Nezar Abdennur
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Job Dekker
- Howard Hughes Medical Institute, Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605-0103, USA
| | - Leonid A Mirny
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Benoit G Bruneau
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158, USA; Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San Francisco, CA 94158, USA; Department of Pediatrics, University of California, San Francisco, CA 94143, USA; Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA.
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24
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Moorthy SD, Davidson S, Shchuka VM, Singh G, Malek-Gilani N, Langroudi L, Martchenko A, So V, Macpherson NN, Mitchell JA. Enhancers and super-enhancers have an equivalent regulatory role in embryonic stem cells through regulation of single or multiple genes. Genome Res 2016; 27:246-258. [PMID: 27895109 PMCID: PMC5287230 DOI: 10.1101/gr.210930.116] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 11/18/2016] [Indexed: 12/31/2022]
Abstract
Transcriptional enhancers are critical for maintaining cell-type-specific gene expression and driving cell fate changes during development. Highly transcribed genes are often associated with a cluster of individual enhancers such as those found in locus control regions. Recently, these have been termed stretch enhancers or super-enhancers, which have been predicted to regulate critical cell identity genes. We employed a CRISPR/Cas9-mediated deletion approach to study the function of several enhancer clusters (ECs) and isolated enhancers in mouse embryonic stem (ES) cells. Our results reveal that the effect of deleting ECs, also classified as ES cell super-enhancers, is highly variable, resulting in target gene expression reductions ranging from 12% to as much as 92%. Partial deletions of these ECs which removed only one enhancer or a subcluster of enhancers revealed partially redundant control of the regulated gene by multiple enhancers within the larger cluster. Many highly transcribed genes in ES cells are not associated with a super-enhancer; furthermore, super-enhancer predictions ignore 81% of the potentially active regulatory elements predicted by cobinding of five or more pluripotency-associated transcription factors. Deletion of these additional enhancer regions revealed their robust regulatory role in gene transcription. In addition, select super-enhancers and enhancers were identified that regulated clusters of paralogous genes. We conclude that, whereas robust transcriptional output can be achieved by an isolated enhancer, clusters of enhancers acting on a common target gene act in a partially redundant manner to fine tune transcriptional output of their target genes.
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Affiliation(s)
- Sakthi D Moorthy
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Scott Davidson
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Virlana M Shchuka
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Gurdeep Singh
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Nakisa Malek-Gilani
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Lida Langroudi
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Alexandre Martchenko
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Vincent So
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Neil N Macpherson
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Jennifer A Mitchell
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada.,Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario M5S 3G5, Canada
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25
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Li Y, Chen H, Pan T, Jiang C, Zhao Z, Wang Z, Zhang J, Xu J, Li X. LncRNA ontology: inferring lncRNA functions based on chromatin states and expression patterns. Oncotarget 2016; 6:39793-805. [PMID: 26485761 PMCID: PMC4741861 DOI: 10.18632/oncotarget.5794] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/05/2015] [Indexed: 02/01/2023] Open
Abstract
Accumulating evidences suggest that long non-coding RNAs (lncRNAs) perform important functions. Genome-wide chromatin-states area rich source of information about cellular state, yielding insights beyond what is typically obtained by transcriptome profiling. We propose an integrative method for genome-wide functional predictions of lncRNAs by combining chromatin states data with gene expression patterns. We first validated the method using protein-coding genes with known function annotations. Our validation results indicated that our integrative method performs better than co-expression analysis, and is accurate across different conditions. Next, by applying the integrative model genome-wide, we predicted the probable functions for more than 97% of human lncRNAs. The putative functions inferred by our method match with previously annotated by the targets of lncRNAs. Moreover, the linkage from the cellular processes influenced by cancer-associated lncRNAs to the cancer hallmarks provided a “lncRNA point-of-view” on tumor biology. Our approach provides a functional annotation of the lncRNAs, which we developed into a web-based application, LncRNA Ontology, to provide visualization, analysis, and downloading of lncRNA putative functions.
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Affiliation(s)
- Yongsheng Li
- College of Bioinformatics Science and Technology and Bio-Pharmaceutical Key Laboratory of Heilongjiang Province, Harbin Medical University, Nangang, Harbin, Heilongjiang, China
| | - Hong Chen
- College of Bioinformatics Science and Technology and Bio-Pharmaceutical Key Laboratory of Heilongjiang Province, Harbin Medical University, Nangang, Harbin, Heilongjiang, China
| | - Tao Pan
- College of Bioinformatics Science and Technology and Bio-Pharmaceutical Key Laboratory of Heilongjiang Province, Harbin Medical University, Nangang, Harbin, Heilongjiang, China
| | - Chunjie Jiang
- College of Bioinformatics Science and Technology and Bio-Pharmaceutical Key Laboratory of Heilongjiang Province, Harbin Medical University, Nangang, Harbin, Heilongjiang, China
| | - Zheng Zhao
- College of Bioinformatics Science and Technology and Bio-Pharmaceutical Key Laboratory of Heilongjiang Province, Harbin Medical University, Nangang, Harbin, Heilongjiang, China
| | - Zishan Wang
- College of Bioinformatics Science and Technology and Bio-Pharmaceutical Key Laboratory of Heilongjiang Province, Harbin Medical University, Nangang, Harbin, Heilongjiang, China
| | - Jinwen Zhang
- College of Bioinformatics Science and Technology and Bio-Pharmaceutical Key Laboratory of Heilongjiang Province, Harbin Medical University, Nangang, Harbin, Heilongjiang, China
| | - Juan Xu
- College of Bioinformatics Science and Technology and Bio-Pharmaceutical Key Laboratory of Heilongjiang Province, Harbin Medical University, Nangang, Harbin, Heilongjiang, China
| | - Xia Li
- College of Bioinformatics Science and Technology and Bio-Pharmaceutical Key Laboratory of Heilongjiang Province, Harbin Medical University, Nangang, Harbin, Heilongjiang, China
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26
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Abstract
The three-dimensional organization of the genome plays important roles in regulating the functional output of the genome and even in the maintenance of epigenetic inheritance and genome stability. Here, we review and compare a number of newly developed methods-especially those that utilize the CRISPR (clustered regularly interspaced short palindromic repeat)-Cas9 (CRISPR-associated protein 9) system-that enable the direct visualization of specific, endogenous DNA sequences in living cells. We also discuss the practical considerations in implementing the CRISPR imaging technique to achieve sufficient signal-to-background levels, high specificity, and high labeling efficiency. These DNA labeling methods enable tracking of the copy number, localization, and movement of genomic elements, and we discuss the potential applications of these methods in understanding the searching and targeting mechanism of the Cas9-sgRNA complex, investigating chromosome organization, and visualizing genome instability and rearrangement.
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Affiliation(s)
- Baohui Chen
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143; , ,
| | - Juan Guan
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143; , ,
| | - Bo Huang
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143; , ,
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27
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Moorthy SD, Mitchell JA. Generating CRISPR/Cas9 Mediated Monoallelic Deletions to Study Enhancer Function in Mouse Embryonic Stem Cells. J Vis Exp 2016:e53552. [PMID: 27078492 DOI: 10.3791/53552] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Enhancers control cell identity by regulating tissue-specific gene expression in a position and orientation independent manner. These enhancers are often located distally from the regulated gene in intergenic regions or even within the body of another gene. The position independent nature of enhancer activity makes it difficult to match enhancers with the genes they regulate. Deletion of an enhancer region provides direct evidence for enhancer activity and is the gold standard to reveal an enhancer's role in endogenous gene transcription. Conventional homologous recombination based deletion methods have been surpassed by recent advances in genome editing technology which enable rapid and precisely located changes to the genomes of numerous model organisms. CRISPR/Cas9 mediated genome editing can be used to manipulate the genome in many cell types and organisms rapidly and cost effectively, due to the ease with which Cas9 can be targeted to the genome by a guide RNA from a bespoke expression plasmid. Homozygous deletion of essential gene regulatory elements might lead to lethality or alter cellular phenotype whereas monoallelic deletion of transcriptional enhancers allows for the study of cis-regulation of gene expression without this confounding issue. Presented here is a protocol for CRISPR/Cas9 mediated deletion in F1 mouse embryonic stem (ES) cells (Mus musculus(129) x Mus castaneus). Monoallelic deletion, screening and expression analysis is facilitated by single nucleotide polymorphisms (SNP) between the two alleles which occur on average every 125 bp in these cells.
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28
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Rizzino A, Wuebben EL. Sox2/Oct4: A delicately balanced partnership in pluripotent stem cells and embryogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:780-91. [PMID: 26992828 DOI: 10.1016/j.bbagrm.2016.03.006] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 11/25/2022]
Abstract
Considerable progress has been made in understanding the roles of Sox2 and Oct4 in embryonic stem cells and mammalian embryogenesis. Specifically, significant progress has been made in answering three questions about the functions of Sox2 and Oct4, which are the focus of this review. 1) Are the first or second cell lineage decisions during embryogenesis controlled by Oct4 and/or Sox2? 2) Do the levels of Oct4 and Sox2 need to be maintained within narrow limits to promote normal development and to sustain the self-renewal of pluripotent stem cells? 3) Do Oct4 and Sox2 work closely together or is the primary role of Sox2 in pluripotent cells to ensure the expression of Oct4? Although significant progress has been made in answering these questions, additional studies are needed to resolve several important remaining issues. Nonetheless, the preponderance of the evidence suggests there is considerable crosstalk between Sox2 and Oct4, and further suggests Sox2 and Oct4 function as molecular rheostats and utilize negative feedback loops to carefully balance their expression and other critical genes during embryogenesis. This article is part of a Special Issue entitled: The Oct transcription factor family, edited by Dr. Dean Tantin.
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Affiliation(s)
- Angie Rizzino
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska 68198-5950, United States.
| | - Erin L Wuebben
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska 68198-5950, United States
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29
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Livyatan I, Aaronson Y, Gokhman D, Ashkenazi R, Meshorer E. BindDB: An Integrated Database and Webtool Platform for “Reverse-ChIP” Epigenomic Analysis. Cell Stem Cell 2015; 17:647-648. [DOI: 10.1016/j.stem.2015.11.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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30
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Liu GY, Zhao GN, Chen XF, Hao DL, Zhao X, Lv X, Liu DP. The long noncoding RNA Gm15055 represses Hoxa gene expression by recruiting PRC2 to the gene cluster. Nucleic Acids Res 2015; 44:2613-27. [PMID: 26615201 PMCID: PMC4824075 DOI: 10.1093/nar/gkv1315] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 11/11/2015] [Indexed: 11/17/2022] Open
Abstract
The Hox genes encode transcription factors that determine embryonic pattern formation. In embryonic stem cells, the Hox genes are silenced by PRC2. Recent studies have reported a role for long noncoding RNAs in PRC2 recruitment in vertebrates. However, little is known about how PRC2 is recruited to the Hox genes in ESCs. Here, we used stable knockdown and knockout strategies to characterize the function of the long noncoding RNA Gm15055 in the regulation of Hoxa genes in mouse ESCs. We found that Gm15055 is highly expressed in mESCs and its expression is maintained by OCT4. Gm15055 represses Hoxa gene expression by recruiting PRC2 to the cluster and maintaining the H3K27me3 modification on Hoxa promoters. A chromosome conformation capture assay revealed the close physical association of the Gm15055 locus to multiple sites at the Hoxa gene cluster in mESCs, which may facilitate the in cis targeting of Gm15055 RNA to the Hoxa genes. Furthermore, an OCT4-responsive positive cis-regulatory element is found in the Gm15055 gene locus, which potentially regulates both Gm15055 itself and the Hoxa gene activation. This study suggests how PRC2 is recruited to the Hoxa locus in mESCs, and implies an elaborate mechanism for Hoxa gene regulation in mESCs.
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Affiliation(s)
- Guo-You Liu
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, P.R. China
| | - Guang-Nian Zhao
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, P.R. China
| | - Xiao-Feng Chen
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, P.R. China
| | - De-Long Hao
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, P.R. China
| | - Xiang Zhao
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, P.R. China
| | - Xiang Lv
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, P.R. China
| | - De-Pei Liu
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, P.R. China
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31
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Li Y, Chen CY, Kaye AM, Wasserman WW. The identification of cis-regulatory elements: A review from a machine learning perspective. Biosystems 2015; 138:6-17. [PMID: 26499213 DOI: 10.1016/j.biosystems.2015.10.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 10/09/2015] [Accepted: 10/14/2015] [Indexed: 01/06/2023]
Abstract
The majority of the human genome consists of non-coding regions that have been called junk DNA. However, recent studies have unveiled that these regions contain cis-regulatory elements, such as promoters, enhancers, silencers, insulators, etc. These regulatory elements can play crucial roles in controlling gene expressions in specific cell types, conditions, and developmental stages. Disruption to these regions could contribute to phenotype changes. Precisely identifying regulatory elements is key to deciphering the mechanisms underlying transcriptional regulation. Cis-regulatory events are complex processes that involve chromatin accessibility, transcription factor binding, DNA methylation, histone modifications, and the interactions between them. The development of next-generation sequencing techniques has allowed us to capture these genomic features in depth. Applied analysis of genome sequences for clinical genetics has increased the urgency for detecting these regions. However, the complexity of cis-regulatory events and the deluge of sequencing data require accurate and efficient computational approaches, in particular, machine learning techniques. In this review, we describe machine learning approaches for predicting transcription factor binding sites, enhancers, and promoters, primarily driven by next-generation sequencing data. Data sources are provided in order to facilitate testing of novel methods. The purpose of this review is to attract computational experts and data scientists to advance this field.
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Affiliation(s)
- Yifeng Li
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia Vancouver, British Columbia V5Z 4H4, Canada; Information and Communications Technologies, National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada.
| | - Chih-Yu Chen
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia Vancouver, British Columbia V5Z 4H4, Canada.
| | - Alice M Kaye
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia Vancouver, British Columbia V5Z 4H4, Canada.
| | - Wyeth W Wasserman
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia Vancouver, British Columbia V5Z 4H4, Canada.
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Chromatin Dynamics in Lineage Commitment and Cellular Reprogramming. Genes (Basel) 2015; 6:641-61. [PMID: 26193323 PMCID: PMC4584322 DOI: 10.3390/genes6030641] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 07/08/2015] [Accepted: 07/10/2015] [Indexed: 12/15/2022] Open
Abstract
Dynamic structural properties of chromatin play an essential role in defining cell identity and function. Transcription factors and chromatin modifiers establish and maintain cell states through alteration of DNA accessibility and histone modifications. This activity is focused at both gene-proximal promoter regions and distally located regulatory elements. In the three-dimensional space of the nucleus, distal elements are localized in close physical proximity to the gene-proximal regulatory sequences through the formation of chromatin loops. These looping features in the genome are highly dynamic as embryonic stem cells differentiate and commit to specific lineages, and throughout reprogramming as differentiated cells reacquire pluripotency. Identifying these functional distal regulatory regions in the genome provides insight into the regulatory processes governing early mammalian development and guidance for improving the protocols that generate induced pluripotent cells.
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Brown CC, Esterhazy D, Sarde A, London M, Pullabhatla V, Osma-Garcia I, Al-Bader R, Ortiz C, Elgueta R, Arno M, de Rinaldis E, Mucida D, Lord GM, Noelle RJ. Retinoic acid is essential for Th1 cell lineage stability and prevents transition to a Th17 cell program. Immunity 2015; 42:499-511. [PMID: 25769610 PMCID: PMC4372260 DOI: 10.1016/j.immuni.2015.02.003] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Revised: 12/18/2014] [Accepted: 01/16/2015] [Indexed: 01/12/2023]
Abstract
CD4(+) T cells differentiate into phenotypically distinct T helper cells upon antigenic stimulation. Regulation of plasticity between these CD4(+) T-cell lineages is critical for immune homeostasis and prevention of autoimmune disease. However, the factors that regulate lineage stability are largely unknown. Here we investigate a role for retinoic acid (RA) in the regulation of lineage stability using T helper 1 (Th1) cells, traditionally considered the most phenotypically stable Th subset. We found that RA, through its receptor RARα, sustains stable expression of Th1 lineage specifying genes, as well as repressing genes that instruct Th17-cell fate. RA signaling is essential for limiting Th1-cell conversion into Th17 effectors and for preventing pathogenic Th17 responses in vivo. Our study identifies RA-RARα as a key component of the regulatory network governing maintenance and plasticity of Th1-cell fate and defines an additional pathway for the development of Th17 cells.
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Affiliation(s)
- Chrysothemis C Brown
- Division of Transplantation Immunology and Mucosal Biology, King's College London, London SE1 9RT, UK.
| | - Daria Esterhazy
- Laboratory of Mucosal Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Aurelien Sarde
- Division of Transplantation Immunology and Mucosal Biology, King's College London, London SE1 9RT, UK
| | - Mariya London
- Laboratory of Mucosal Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Venu Pullabhatla
- National Institute for Health Research Biomedical Research Centre at Guy's & St Thomas' National Health Service Foundation Trust and King's College London, London SE1 9RT, UK
| | - Ines Osma-Garcia
- Division of Transplantation Immunology and Mucosal Biology, King's College London, London SE1 9RT, UK
| | - Raya Al-Bader
- Division of Transplantation Immunology and Mucosal Biology, King's College London, London SE1 9RT, UK
| | - Carla Ortiz
- Division of Transplantation Immunology and Mucosal Biology, King's College London, London SE1 9RT, UK
| | - Raul Elgueta
- Division of Transplantation Immunology and Mucosal Biology, King's College London, London SE1 9RT, UK
| | - Matthew Arno
- Genomics Centre, King's College London, London SE1 9NH, UK
| | - Emanuele de Rinaldis
- National Institute for Health Research Biomedical Research Centre at Guy's & St Thomas' National Health Service Foundation Trust and King's College London, London SE1 9RT, UK; Division of Cancer Studies, School of Medicine, King's College London, Guy's Hospital, London SE1 9RT, UK
| | - Daniel Mucida
- Laboratory of Mucosal Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Graham M Lord
- Division of Transplantation Immunology and Mucosal Biology, King's College London, London SE1 9RT, UK; National Institute for Health Research Biomedical Research Centre at Guy's & St Thomas' National Health Service Foundation Trust and King's College London, London SE1 9RT, UK
| | - Randolph J Noelle
- Division of Transplantation Immunology and Mucosal Biology, King's College London, London SE1 9RT, UK; Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, NH 03756, USA.
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Zhou HY, Katsman Y, Dhaliwal NK, Davidson S, Macpherson NN, Sakthidevi M, Collura F, Mitchell JA. A Sox2 distal enhancer cluster regulates embryonic stem cell differentiation potential. Genes Dev 2015; 28:2699-711. [PMID: 25512558 PMCID: PMC4265674 DOI: 10.1101/gad.248526.114] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The Sox2 transcription factor must be robustly transcribed in embryonic stem (ES) cells to maintain pluripotency. Zhou et al. identify three novel enhancers that, through the formation of chromatin loops, form a chromatin complex with the Sox2 promoter in ES cells. The distal cluster containing SRR107 and SRR111, located >100 kb downstream from Sox2, is required for cis-regulation of Sox2 in ES cells. The Sox2 transcription factor must be robustly transcribed in embryonic stem (ES) cells to maintain pluripotency. Two gene-proximal enhancers, Sox2 regulatory region 1 (SRR1) and SRR2, display activity in reporter assays, but deleting SRR1 has no effect on pluripotency. We identified and functionally validated the sequences required for Sox2 transcription based on a computational model that predicted transcriptional enhancer elements within 130 kb of Sox2. Our reporter assays revealed three novel enhancers—SRR18, SRR107, and SRR111—that, through the formation of chromatin loops, form a chromatin complex with the Sox2 promoter in ES cells. Using the CRISPR/Cas9 system and F1 ES cells (Mus musculus129 × Mus castaneus), we generated heterozygous deletions of each enhancer region, revealing that only the distal cluster containing SRR107 and SRR111, located >100 kb downstream from Sox2, is required for cis-regulation of Sox2 in ES cells. Furthermore, homozygous deletion of this distal Sox2 control region (SCR) caused significant reduction in Sox2 mRNA and protein levels, loss of ES cell colony morphology, genome-wide changes in gene expression, and impaired neuroectodermal formation upon spontaneous differentiation to embryoid bodies. Together, these data identify a distal control region essential for Sox2 transcription in ES cells.
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Affiliation(s)
- Harry Y Zhou
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Yulia Katsman
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Navroop K Dhaliwal
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Scott Davidson
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Neil N Macpherson
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Moorthy Sakthidevi
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Felicia Collura
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Jennifer A Mitchell
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada; Center for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario M5S 3G5, Canada
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Whitaker JW, Nguyen TT, Zhu Y, Wildberg A, Wang W. Computational schemes for the prediction and annotation of enhancers from epigenomic assays. Methods 2015; 72:86-94. [PMID: 25461775 PMCID: PMC4778972 DOI: 10.1016/j.ymeth.2014.10.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 09/14/2014] [Accepted: 10/08/2014] [Indexed: 12/31/2022] Open
Abstract
Identifying and annotating distal regulatory enhancers is critical to understand the mechanisms that control gene expression and cell-type-specific activities. Next-generation sequencing techniques have provided us an exciting toolkit of genome-wide assays that can be used to predict and annotate enhancers. However, each assay comes with its own specific set of analytical needs if enhancer prediction is to be optimal. Furthermore, integration of multiple genome-wide assays allows for different genomic features to be combined, and can improve predictive performance. Herein, we review the genome-wide assays and analysis schemes that are used to predict and annotate enhancers. In particular, we focus on three key computational topics: predicting enhancer locations, determining the cell-type-specific activity of enhancers, and linking enhancers to their target genes.
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Affiliation(s)
- John W Whitaker
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0359, United States; Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0359, United States
| | - Tung T Nguyen
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0359, United States; Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0359, United States
| | - Yun Zhu
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0359, United States; Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0359, United States
| | - Andre Wildberg
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0359, United States; Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0359, United States
| | - Wei Wang
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0359, United States; Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0359, United States.
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Beck S, Lee BK, Rhee C, Song J, Woo AJ, Kim J. CpG island-mediated global gene regulatory modes in mouse embryonic stem cells. Nat Commun 2014; 5:5490. [PMID: 25405324 PMCID: PMC4236720 DOI: 10.1038/ncomms6490] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 10/03/2014] [Indexed: 12/13/2022] Open
Abstract
Both transcriptional and epigenetic regulations are fundamental for the control of eukaryotic gene expression. Here we perform a compendium analysis of >200 large sequencing data sets to elucidate the regulatory logic of global gene expression programs in mouse embryonic stem (ES) cells. We define four major classes of DNA-binding proteins (Core, PRC, MYC and CTCF) based on their target co-occupancy, and discover reciprocal regulation between the MYC and PRC classes for the activity of nearly all genes under the control of the CpG island (CGI)-containing promoters. This CGI-dependent regulatory mode explains the functional segregation between CGI-containing and CGI-less genes during early development. By defining active enhancers based on the co-occupancy of the Core class, we further demonstrate their additive roles in CGI-containing gene expression and cell type-specific roles in CGI-less gene expression. Altogether, our analyses provide novel insights into previously unknown CGI-dependent global gene regulatory modes.
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Affiliation(s)
- Samuel Beck
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Bum-Kyu Lee
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Catherine Rhee
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Jawon Song
- Texas Advanced Computing Center, The University of Texas at Austin, Austin, Texas 78758, USA
| | - Andrew J Woo
- School of Medicine and Pharmacology, Royal Perth Hospital Unit, The University of Western Australia, Perth, WA 6000, Australia
| | - Jonghwan Kim
- 1] Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA [2] Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA [3] Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, USA
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Sharov AA, Nishiyama A, Qian Y, Dudekula DB, Longo DL, Schlessinger D, Ko MSH. Chromatin properties of regulatory DNA probed by manipulation of transcription factors. J Comput Biol 2014; 21:569-77. [PMID: 24918633 DOI: 10.1089/cmb.2013.0126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Transcription factors (TFs) bind to DNA and regulate the transcription of nearby genes. However, only a small fraction of TF binding sites have such regulatory effects. Here we search for the predictors of functional binding sites by carrying out a systematic computational screening of a variety of contextual factors (histone modifications, nuclear lamin-bindings, and cofactor bindings). We used regression analysis to test if contextual factors are associated with upregulation or downregulation of neighboring genes following the induction or knockdown of the 9 TFs in mouse embryonic stem (ES) cells. Functional TF binding sites appeared to be either active (i.e., bound by P300, CHD7, mediator, cohesin, and SWI/SNF) or repressed (i.e., with H3K27me3 histone marks and bound by Polycomb factors). Active binding sites mediated the downregulation of nearby genes upon knocking down the activating TFs or inducing repressors. Repressed TF binding sites mediated the upregulation of nearby genes (e.g., poised developmental regulators) upon inducing TFs. In addition, repressed binding sites mediated repressive effects of TFs, identified by the downregulation of target genes after the induction of TFs or by the upregulation of target genes after the knockdown of TFs. The contextual factors associated with functions of DNA-bound TFs were used to improve the identification of candidate target genes regulated by TFs.
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Affiliation(s)
- Alexei A Sharov
- 1 National Institute on Aging, National Institutes of Health , Baltimore, Maryland
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38
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Chen CY, Chang IS, Hsiung CA, Wasserman WW. On the identification of potential regulatory variants within genome wide association candidate SNP sets. BMC Med Genomics 2014; 7:34. [PMID: 24920305 PMCID: PMC4066296 DOI: 10.1186/1755-8794-7-34] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 06/02/2014] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Genome wide association studies (GWAS) are a population-scale approach to the identification of segments of the genome in which genetic variations may contribute to disease risk. Current methods focus on the discovery of single nucleotide polymorphisms (SNPs) associated with disease traits. As there are many SNPs within identified risk loci, and the majority of these are situated within non-coding regions, a key challenge is to identify and prioritize variants affecting regulatory sequences that are likely to contribute to the phenotype assessed. METHODS We focused investigation on SNPs within lung and breast cancer GWAS loci that reached genome-wide significance for potential roles in gene regulation with a specific focus on SNPs likely to disrupt transcription factor binding sites. Within risk loci, the regulatory potential of sub-regions was classified using relevant open chromatin and epigenetic high throughput sequencing data sets from the ENCODE project in available cancer and normal cell lines. Furthermore, transcription factor affinity altering variants were predicted by comparison of position weight matrix scores between disease and reference alleles. Lastly, ChIP-seq data of transcription associated factors and topological domains were included as binding evidence and potential gene target inference. RESULTS The sets of SNPs, including both the disease-associated markers and those in high linkage disequilibrium with them, were significantly over-represented in regulatory sequences of cancer and/or normal cells; however, over-representation was generally not restricted to disease-relevant tissue specific regions. The calculated regulatory potential, allelic binding affinity scores and ChIP-seq binding evidence were the three criteria used to prioritize candidates. Fitting all three criteria, we highlighted breast cancer susceptibility SNPs and a borderline lung cancer relevant SNP located in cancer-specific enhancers overlapping multiple distinct transcription associated factor ChIP-seq binding sites. CONCLUSION Incorporating high throughput sequencing epigenetic and transcription factor data sets from both cancer and normal cells into cancer genetic studies reveals potential functional SNPs and informs subsequent characterization efforts.
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Affiliation(s)
- Chih-yu Chen
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Graduate Program in Bioinformatics, University of British Columbia, Vancouver, British Columbia, Canada
| | - I-Shou Chang
- National Institute of Cancer Research, National Health Research Institutes, Zhunan, Taiwan
| | - Chao A Hsiung
- Division of Biostatistics and Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Taiwan
| | - Wyeth W Wasserman
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
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39
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Getting down to the core of histone modifications. Chromosoma 2014; 123:355-71. [PMID: 24789118 DOI: 10.1007/s00412-014-0465-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 04/08/2014] [Accepted: 04/09/2014] [Indexed: 10/25/2022]
Abstract
The identification of an increasing number of posttranslationally modified residues within histone core domains is furthering our understanding of how nucleosome dynamics are regulated. In this review, we first discuss how the targeting of specific histone H3 core residues can directly influence the nucleosome structure and then apply this knowledge to provide functional reasoning for their localization to distinct genomic regions. While we focus mainly on transcriptional implications, the principles discussed in this review can also be applied to their roles in other cellular processes. Finally, we highlight some examples of how aberrant modifications of core histone residues can facilitate the pathogenesis of some diseases.
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40
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FIREWACh: high-throughput functional detection of transcriptional regulatory modules in mammalian cells. Nat Methods 2014; 11:559-65. [PMID: 24658142 PMCID: PMC4020622 DOI: 10.1038/nmeth.2885] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 01/28/2014] [Indexed: 11/08/2022]
Abstract
Promoters and enhancers establish precise gene transcription patterns. The development of functional approaches for their identification in mammalian cells has been complicated by the size of these genomes. Here we report a high-throughput functional assay for directly identifying active promoter and enhancer elements called FIREWACh (Functional Identification of Regulatory Elements Within Accessible Chromatin), which we used to simultaneously assess over 80,000 DNA fragments derived from nucleosome-free regions within the chromatin of embryonic stem cells (ESCs) and identify 6,364 active regulatory elements. Many of these represent newly discovered ESC-specific enhancers, showing enriched binding-site motifs for ESC-specific transcription factors including SOX2, POU5F1 (OCT4) and KLF4. The application of FIREWACh to additional cultured cell types will facilitate functional annotation of the genome and expand our view of transcriptional network dynamics.
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41
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Tran NTL, Huang CH. Gene Expression and Gene Ontology Enrichment Analysis for H3K4me3 and H3K4me1 in Mouse Liver and Mouse Embryonic Stem Cell Using ChIP-Seq and RNA-Seq. GENE REGULATION AND SYSTEMS BIOLOGY 2014; 8:33-43. [PMID: 24526835 PMCID: PMC3921077 DOI: 10.4137/grsb.s13612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 12/09/2013] [Accepted: 12/11/2013] [Indexed: 01/17/2023]
Abstract
Recent study has identified the cis-regulatory elements in the mouse genome as well as their genomic localizations. Recent discoveries have shown the enrichment of H3 lysine 4 trimethylation (H3K4me3) binding as an active promoter and the presence of H3 lysine 4 monomethylation (H3K4me1) outside promoter regions as a mark for an enhancer. In this work, we further identified highly expressed genes by H3K4me3 mark or by both H3K4me3 and H3K4me1 marks in mouse liver using ChIP-Seq and RNA-Seq. We found that in mice, the liver carries embryonic stem cell-related functions while the embryonic stem cell also carries liver-related functions. We also identified novel genes in RNA-Seq experiments for mouse liver and for mouse embryonic stem cells. These genes are not currently in the Ensemble gene database at NCBI.
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Affiliation(s)
- Ngoc Tam L Tran
- Department of Computer Science and Engineering, University of Connecticut, Storrs, CT, USA
| | - Chun-Hsi Huang
- Department of Computer Science and Engineering, University of Connecticut, Storrs, CT, USA
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42
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Woods SA, Robinson HB, Kohler LJ, Agamanolis D, Sterbenz G, Khalifa M. Exome sequencing identifies a novel EP300 frame shift mutation in a patient with features that overlap Cornelia de Lange syndrome. Am J Med Genet A 2013; 164A:251-8. [PMID: 24352918 DOI: 10.1002/ajmg.a.36237] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 08/25/2013] [Indexed: 12/20/2022]
Abstract
Rubinstein-Taybi syndrome (RTS) and Cornelia de Lange syndrome (CdLS) are genetically heterogeneous multiple anomalies syndromes, each having a distinctive facial gestalt. Two genes (CREBBP and EP300) are known to cause RTS, and five (NIPBL, SMC1A, SMC3, RAD21, and HDAC8) have been associated with CdLS. A diagnosis of RTS or CdLS is molecularly confirmed in only 65% of clinically identified cases, suggesting that additional causative genes exist for both conditions. In addition, although EP300 and CREBBP encode homologous proteins and perform similar functions, only eight EP300 positive RTS patients have been reported, suggesting that patients with EP300 mutations might be escaping clinical recognition. We report on a child with multiple congenital abnormalities and intellectual disability whose facial features and complex phenotype resemble CdLS. However, no mutations in CdLS-related genes were identified. Rather, a novel EP300 mutation was found on whole exome sequencing. Possible links between EP300 and genes causing CdLS are evident in the literature. Both EP300 and HDAC8 are involved in the regulation of TP53 transcriptional activity. In addition, p300 and other chromatin associated proteins, including NIPBL, SMCA1, and SMC3, have been found at enhancer regions in different cell types. It is therefore possible that EP300 and CdLS-related genes are involved in additional shared pathways, producing overlapping phenotypes. As whole exome sequencing becomes more widely utilized, the diverse phenotypes associated with EP300 mutations should be better understood. In the meantime, testing for EP300 mutations in those with features of CdLS may be warranted.
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Affiliation(s)
- Susan A Woods
- Department of Genetics, Akron Children's Hospital, Akron, Ohio
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Wang C, Zhang MQ, Zhang Z. Computational identification of active enhancers in model organisms. GENOMICS, PROTEOMICS & BIOINFORMATICS 2013; 11:142-50. [PMID: 23685394 PMCID: PMC4357786 DOI: 10.1016/j.gpb.2013.04.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 04/01/2013] [Accepted: 04/20/2013] [Indexed: 12/11/2022]
Abstract
As a class of cis-regulatory elements, enhancers were first identified as the genomic regions that are able to markedly increase the transcription of genes nearly 30years ago. Enhancers can regulate gene expression in a cell-type specific and developmental stage specific manner. Although experimental technologies have been developed to identify enhancers genome-wide, the design principle of the regulatory elements and the way they rewire the transcriptional regulatory network tempo-spatially are far from clear. At present, developing predictive methods for enhancers, particularly for the cell-type specific activity of enhancers, is central to computational biology. In this review, we survey the current computational approaches for active enhancer prediction and discuss future directions.
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Affiliation(s)
- Chengqi Wang
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Michael Q. Zhang
- Department of Molecular Cell Biology, Center for Systems Biology, University of Texas at Dallas, Richardson, TX 75080, USA
- Bioinformatics Division, Center for Synthetic and Systems Biology, TNLIST, Tsinghua University, Beijing 100084, China
| | - Zhihua Zhang
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
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Davidson S, Macpherson N, Mitchell JA. Nuclear organization of RNA polymerase II transcription. Biochem Cell Biol 2013; 91:22-30. [PMID: 23442138 DOI: 10.1139/bcb-2012-0059] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Transcription occurs at distinct nuclear compartments termed transcription factories that are specialized for transcription by 1 of the 3 polymerase complexes (I, II, or III). Protein-coding genes appear to move in and out of RNA polymerase II (RNAPII) compartments as they are expressed and silenced. In addition, transcription factories are sites where several transcription units, either from the same chromosome or different chromosomes, are transcribed. Chromosomes occupy distinct territories in the interphase nucleus with active genes preferentially positioned on the periphery or even looped out of the territory. These chromosome territories have been observed to intermingle in the nucleus, and multiple interactions among different chromosomes have been identified in genome-wide studies. Deep sequencing of the transcriptome and RNAPII associated on DNA obtained by chromatin immunoprecipitation have revealed a plethora of noncoding transcription and intergenic accumulations of RNAPII that must also be considered in models of genome function. The organization of transcription into distinct regions of the nucleus has changed the way we view transcription with the evolving model for silencing or activation of gene expression involving physical relocation of the transcription unit to a silencing or activation compartment, thus, highlighting the need to consider the process of transcription in the 3-dimensional nuclear space.
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Affiliation(s)
- Scott Davidson
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada
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45
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Su MY, Steiner LA, Bogardus H, Mishra T, Schulz VP, Hardison RC, Gallagher PG. Identification of biologically relevant enhancers in human erythroid cells. J Biol Chem 2013; 288:8433-8444. [PMID: 23341446 DOI: 10.1074/jbc.m112.413260] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Identification of cell type-specific enhancers is important for understanding the regulation of programs controlling cellular development and differentiation. Enhancers are typically marked by the co-transcriptional activator protein p300 or by groups of cell-expressed transcription factors. We hypothesized that a unique set of enhancers regulates gene expression in human erythroid cells, a highly specialized cell type evolved to provide adequate amounts of oxygen throughout the body. Using chromatin immunoprecipitation followed by massively parallel sequencing, genome-wide maps of candidate enhancers were constructed for p300 and four transcription factors, GATA1, NF-E2, KLF1, and SCL, using primary human erythroid cells. These data were combined with gene expression analyses, and candidate enhancers were identified. Consistent with their predicted function as candidate enhancers, there was statistically significant enrichment of p300 and combinations of co-localizing erythroid transcription factors within 1-50 kb of the transcriptional start site (TSS) of genes highly expressed in erythroid cells. Candidate enhancers were also enriched near genes with known erythroid cell function or phenotype. Candidate enhancers exhibited moderate conservation with mouse and minimal conservation with nonplacental vertebrates. Candidate enhancers were mapped to a set of erythroid-associated, biologically relevant, SNPs from the genome-wide association studies (GWAS) catalogue of NHGRI, National Institutes of Health. Fourteen candidate enhancers, representing 10 genetic loci, mapped to sites associated with biologically relevant erythroid traits. Fragments from these loci directed statistically significant expression in reporter gene assays. Identification of enhancers in human erythroid cells will allow a better understanding of erythroid cell development, differentiation, structure, and function and provide insights into inherited and acquired hematologic disease.
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Affiliation(s)
- Mack Y Su
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Laurie A Steiner
- Department of Pediatrics, University of Rochester, Rochester, New York 14642
| | - Hannah Bogardus
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Tejaswini Mishra
- Department of Biochemistry and Molecular Biology, Center for Comparative Genomics and Bioinformatics, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Vincent P Schulz
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Ross C Hardison
- Department of Biochemistry and Molecular Biology, Center for Comparative Genomics and Bioinformatics, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Patrick G Gallagher
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06520; Departments of Pathology and Genetics, Yale University School of Medicine, New Haven, Connecticut 06520.
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Upstream distal regulatory elements contact the Lmo2 promoter in mouse erythroid cells. PLoS One 2012; 7:e52880. [PMID: 23285212 PMCID: PMC3528669 DOI: 10.1371/journal.pone.0052880] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 11/22/2012] [Indexed: 01/06/2023] Open
Abstract
The Lim domain only 2 (Lmo2) gene encodes a transcriptional cofactor critical for the development of hematopoietic stem cells. Several distal regulatory elements have been identified upstream of the Lmo2 gene in the human and mouse genomes that are capable of enhancing reporter gene expression in erythroid cells and may be responsible for the high level transcription of Lmo2 in the erythroid lineage. In this study we investigate how these elements regulate transcription of Lmo2 and whether or not they function cooperatively in the endogenous context. Chromosome conformation capture (3C) experiments show that chromatin-chromatin interactions exist between upstream regulatory elements and the Lmo2 promoter in erythroid cells but that these interactions are absent from kidney where Lmo2 is transcribed at twelve fold lower levels. Specifically, long range chromatin-chromatin interactions occur between the Lmo2 proximal promoter and two broad regions, 3–31 and 66–105 kb upstream of Lmo2, which we term the proximal and distal control regions for Lmo2 (pCR and dCR respectively). Each of these regions is bound by several transcription factors suggesting that multiple regulatory elements cooperate in regulating high level transcription of Lmo2 in erythroid cells. Binding of CTCF and cohesin which support chromatin loops at other loci were also found within the dCR and at the Lmo2 proximal promoter. Intergenic transcription occurs throughout the dCR in erythroid cells but not in kidney suggesting a role for these intergenic transcripts in regulating Lmo2, similar to the broad domain of intergenic transcription observed at the human β-globin locus control region. Our data supports a model in which the dCR functions through a chromatin looping mechanism to contact and enhance Lmo2 transcription specifically in erythroid cells. Furthermore, these chromatin loops are supported by the cohesin complex recruited to both CTCF and transcription factor bound regions.
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MacKenzie A, Hing B, Davidson S. Exploring the effects of polymorphisms on cis-regulatory signal transduction response. Trends Mol Med 2012; 19:99-107. [PMID: 23265842 PMCID: PMC3569712 DOI: 10.1016/j.molmed.2012.11.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 10/11/2012] [Accepted: 11/09/2012] [Indexed: 12/20/2022]
Abstract
cis-Regulatory sequences (CRSs) direct cell-specific and inducible gene expression in response to signal transduction networks, and it is becoming apparent that many cases of disease susceptibility and drug response stratification are due to polymorphisms that alter CRS responses in a context-dependent manner. In the current review, we describe successful methods for identifying CRSs and analyzing the effects of allelic variation on their responses to signal transduction. The technologies described build on the successes of ENCODE (ENCyclopedia Of DNA Elements) by exploring the effects of polymorphisms on CRS context dependency. This understanding is essential to uncover the genomic basis of disease susceptibility and will play a major role in delivering on the promise of personalized medicine.
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Affiliation(s)
- Alasdair MacKenzie
- Gene Regulatory Systems Laboratory, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland AB25 2ZD, UK.
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48
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Mitchell JA, Clay I, Umlauf D, Chen CY, Moir CA, Eskiw CH, Schoenfelder S, Chakalova L, Nagano T, Fraser P. Nuclear RNA sequencing of the mouse erythroid cell transcriptome. PLoS One 2012; 7:e49274. [PMID: 23209567 PMCID: PMC3510205 DOI: 10.1371/journal.pone.0049274] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 10/08/2012] [Indexed: 12/31/2022] Open
Abstract
In addition to protein coding genes a substantial proportion of mammalian genomes are transcribed. However, most transcriptome studies investigate steady-state mRNA levels, ignoring a considerable fraction of the transcribed genome. In addition, steady-state mRNA levels are influenced by both transcriptional and posttranscriptional mechanisms, and thus do not provide a clear picture of transcriptional output. Here, using deep sequencing of nuclear RNAs (nucRNA-Seq) in parallel with chromatin immunoprecipitation sequencing (ChIP-Seq) of active RNA polymerase II, we compared the nuclear transcriptome of mouse anemic spleen erythroid cells with polymerase occupancy on a genome-wide scale. We demonstrate that unspliced transcripts quantified by nucRNA-seq correlate with primary transcript frequencies measured by RNA FISH, but differ from steady-state mRNA levels measured by poly(A)-enriched RNA-seq. Highly expressed protein coding genes showed good correlation between RNAPII occupancy and transcriptional output; however, genome-wide we observed a poor correlation between transcriptional output and RNAPII association. This poor correlation is due to intergenic regions associated with RNAPII which correspond with transcription factor bound regulatory regions and a group of stable, nuclear-retained long non-coding transcripts. In conclusion, sequencing the nuclear transcriptome provides an opportunity to investigate the transcriptional landscape in a given cell type through quantification of unspliced primary transcripts and the identification of nuclear-retained long non-coding RNAs.
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Affiliation(s)
- Jennifer A Mitchell
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada.
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Marsman J, Horsfield JA. Long distance relationships: enhancer-promoter communication and dynamic gene transcription. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1819:1217-27. [PMID: 23124110 DOI: 10.1016/j.bbagrm.2012.10.008] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 10/18/2012] [Accepted: 10/22/2012] [Indexed: 11/27/2022]
Abstract
The three-dimensional regulation of gene transcription involves loop formation between enhancer and promoter elements, controlling spatiotemporal gene expression in multicellular organisms. Enhancers are usually located in non-coding DNA and can activate gene transcription by recruiting transcription factors, chromatin remodeling factors and RNA Polymerase II. Research over the last few years has revealed that enhancers have tell-tale characteristics that facilitate their detection by several approaches, although the hallmarks of enhancers are not always uniform. Enhancers likely play an important role in the activation of genes by functioning as a primary point of contact for transcriptional activators, and by making physical contact with gene promoters often by means of a chromatin loop. Although numerous transcriptional regulators participate in the formation of chromatin loops that bring enhancers into proximity with promoters, the mechanism(s) of enhancer-promoter connectivity remain enigmatic. Here we discuss enhancer function, review some of the many proteins shown to be involved in establishing enhancer-promoter loops, and describe the dynamics of enhancer-promoter contacts during development, differentiation and in specific cell types.
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Affiliation(s)
- Judith Marsman
- Department of Pathology, The University of Otago, Dunedin, New Zealand
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