201
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Genetic and epigenetic features direct differential efficiency of Xist-mediated silencing at X-chromosomal and autosomal locations. Nat Commun 2017; 8:690. [PMID: 28947736 PMCID: PMC5612955 DOI: 10.1038/s41467-017-00528-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 07/06/2017] [Indexed: 02/02/2023] Open
Abstract
Xist is indispensable for X chromosome inactivation. However, how Xist RNA directs chromosome-wide silencing and why some regions are more efficiently silenced than others remains unknown. Here, we explore the function of Xist by inducing ectopic Xist expression from multiple different X-linked and autosomal loci in mouse aneuploid and female diploid embryonic stem cells in which Xist-mediated silencing does not lead to lethal functional monosomy. We show that ectopic Xist expression faithfully recapitulates endogenous X chromosome inactivation from any location on the X chromosome, whereas long-range silencing of autosomal genes is less efficient. Long interspersed elements facilitate inactivation of genes located far away from the Xist transcription locus, and genes escaping X chromosome inactivation show enrichment of CTCF on X chromosomal but not autosomal loci. Our findings highlight important genomic and epigenetic features acquired during sex chromosome evolution to facilitate an efficient X chromosome inactivation process.Xist RNA is required for X chromosome inactivation but it is not well understood how Xist silences some regions more efficiently than others. Here, the authors induce ectopic Xist expression from multiple different X-linked and autosomal loci in cells to explore Xist function.
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202
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Harmston N, Ing-Simmons E, Tan G, Perry M, Merkenschlager M, Lenhard B. Topologically associating domains are ancient features that coincide with Metazoan clusters of extreme noncoding conservation. Nat Commun 2017; 8:441. [PMID: 28874668 PMCID: PMC5585340 DOI: 10.1038/s41467-017-00524-5] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 07/05/2017] [Indexed: 02/08/2023] Open
Abstract
Developmental genes in metazoan genomes are surrounded by dense clusters of conserved noncoding elements (CNEs). CNEs exhibit unexplained extreme levels of sequence conservation, with many acting as developmental long-range enhancers. Clusters of CNEs define the span of regulatory inputs for many important developmental regulators and have been described previously as genomic regulatory blocks (GRBs). Their function and distribution around important regulatory genes raises the question of how they relate to 3D conformation of these loci. Here, we show that clusters of CNEs strongly coincide with topological organisation, predicting the boundaries of hundreds of topologically associating domains (TADs) in human and Drosophila. The set of TADs that are associated with high levels of noncoding conservation exhibit distinct properties compared to TADs devoid of extreme noncoding conservation. The close correspondence between extreme noncoding conservation and TADs suggests that these TADs are ancient, revealing a regulatory architecture conserved over hundreds of millions of years. Metazoan genomes contain many clusters of conserved noncoding elements. Here, the authors provide evidence that these clusters coincide with distinct topologically associating domains in humans and Drosophila, revealing a conserved regulatory genomic architecture.
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Affiliation(s)
- Nathan Harmston
- Computational Regulatory Genomics, MRC London Institute of Medical Sciences, London, W12 0NN, UK. .,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK. .,Program in Cardiovascular and Metabolic Disease, Duke-NUS Graduate Medical School, 8 College Road, Singapore, 169857, Singapore.
| | - Elizabeth Ing-Simmons
- Computational Regulatory Genomics, MRC London Institute of Medical Sciences, London, W12 0NN, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK.,Lymphocyte Development, MRC London Institute of Medical Sciences, London, W12 0NN, UK
| | - Ge Tan
- Computational Regulatory Genomics, MRC London Institute of Medical Sciences, London, W12 0NN, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Malcolm Perry
- Computational Regulatory Genomics, MRC London Institute of Medical Sciences, London, W12 0NN, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Matthias Merkenschlager
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK.,Lymphocyte Development, MRC London Institute of Medical Sciences, London, W12 0NN, UK
| | - Boris Lenhard
- Computational Regulatory Genomics, MRC London Institute of Medical Sciences, London, W12 0NN, UK. .,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK. .,Sars International Centre for Marine Molecular Biology, University of Bergen, N-5008, Bergen, Norway.
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203
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Trizzino M, Park Y, Holsbach-Beltrame M, Aracena K, Mika K, Caliskan M, Perry GH, Lynch VJ, Brown CD. Transposable elements are the primary source of novelty in primate gene regulation. Genome Res 2017; 27:1623-1633. [PMID: 28855262 PMCID: PMC5630026 DOI: 10.1101/gr.218149.116] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 08/17/2017] [Indexed: 12/11/2022]
Abstract
Gene regulation shapes the evolution of phenotypic diversity. We investigated the evolution of liver promoters and enhancers in six primate species using ChIP-seq (H3K27ac and H3K4me1) to profile cis-regulatory elements (CREs) and using RNA-seq to characterize gene expression in the same individuals. To quantify regulatory divergence, we compared CRE activity across species by testing differential ChIP-seq read depths directly measured for orthologous sequences. We show that the primate regulatory landscape is largely conserved across the lineage, with 63% of the tested human liver CREs showing similar activity across species. Conserved CRE function is associated with sequence conservation, proximity to coding genes, cell-type specificity, and transcription factor binding. Newly evolved CREs are enriched in immune response and neurodevelopmental functions. We further demonstrate that conserved CREs bind master regulators, suggesting that while CREs contribute to species adaptation to the environment, core functions remain intact. Newly evolved CREs are enriched in young transposable elements (TEs), including Long-Terminal-Repeats (LTRs) and SINE-VNTR-Alus (SVAs), that significantly affect gene expression. Conversely, only 16% of conserved CREs overlap TEs. We tested the cis-regulatory activity of 69 TE subfamilies by luciferase reporter assays, spanning all major TE classes, and showed that 95.6% of tested TEs can function as either transcriptional activators or repressors. In conclusion, we demonstrated the critical role of TEs in primate gene regulation and illustrated potential mechanisms underlying evolutionary divergence among the primate species through the noncoding genome.
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Affiliation(s)
- Marco Trizzino
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.,Institute for Biomedical Informatics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - YoSon Park
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.,Institute for Biomedical Informatics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Marcia Holsbach-Beltrame
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Katherine Aracena
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Katelyn Mika
- Department of Human Genetics, University of Chicago, Chicago, Illinois 60637, USA
| | - Minal Caliskan
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.,Institute for Biomedical Informatics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - George H Perry
- Departments of Anthropology and Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Vincent J Lynch
- Department of Human Genetics, University of Chicago, Chicago, Illinois 60637, USA
| | - Christopher D Brown
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.,Institute for Biomedical Informatics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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204
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Dong Y, Huang Z, Kuang Q, Wen Z, Liu Z, Li Y, Yang Y, Li M. Expression dynamics and relations with nearby genes of rat transposable elements across 11 organs, 4 developmental stages and both sexes. BMC Genomics 2017; 18:666. [PMID: 28851270 PMCID: PMC5576108 DOI: 10.1186/s12864-017-4078-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 08/21/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND TEs pervade mammalian genomes. However, compared with mice, fewer studies have focused on the TE expression patterns in rat, particularly the comparisons across different organs, developmental stages and sexes. In addition, TEs can influence the expression of nearby genes. The temporal and spatial influences of TEs remain unclear yet. RESULTS To evaluate the TEs transcription patterns, we profiled their transcript levels in 11 organs for both sexes across four developmental stages of rat. The results show that most short interspersed elements (SINEs) are commonly expressed in all conditions, which are also the major TE types with commonly expression patterns. In contrast, long terminal repeats (LTRs) are more likely to exhibit specific expression patterns. The expression tendency of TEs and genes are similar in most cases. For example, few specific genes and TEs are in the liver, muscle and heart. However, TEs perform superior over genes on classing organ, which imply their higher organ specificity than genes. By associating the TEs with the closest genes in genome, we find their expression levels are correlated, independent of their distance in some cases. CONCLUSIONS TEs sex-dependently associate with nearest genes. A gene would be associated with more than one TE. Our works can help to functionally annotate the genome and further understand the role of TEs in gene regulation.
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Affiliation(s)
- Yongcheng Dong
- College of Life Science, Sichuan University, Chengdu, 610064, China
| | - Ziyan Huang
- College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Qifan Kuang
- College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Zhining Wen
- College of Chemistry, Sichuan University, Chengdu, 610064, China
| | - Zhibin Liu
- College of Life Science, Sichuan University, Chengdu, 610064, China
| | - Yizhou Li
- College of Chemistry, Sichuan University, Chengdu, 610064, China.
| | - Yi Yang
- College of Life Science, Sichuan University, Chengdu, 610064, China.
| | - Menglong Li
- College of Chemistry, Sichuan University, Chengdu, 610064, China
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205
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Zernov NV, Marakhonov AV, Vyakhireva JV, Guskova AA, Dadali EL, Skoblov MY. Clinical and genetic characteristics and diagnostic features of Landouzy–Dejerine facioscapulohumeral muscular dystrophy. RUSS J GENET+ 2017. [DOI: 10.1134/s102279541706014x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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206
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Abstract
Cross-species comparisons of genomes, transcriptomes and gene regulation are now feasible at unprecedented resolution and throughput, enabling the comparison of human and mouse biology at the molecular level. Insights have been gained into the degree of conservation between human and mouse at the level of not only gene expression but also epigenetics and inter-individual variation. However, a number of limitations exist, including incomplete transcriptome characterization and difficulties in identifying orthologous phenotypes and cell types, which are beginning to be addressed by emerging technologies. Ultimately, these comparisons will help to identify the conditions under which the mouse is a suitable model of human physiology and disease, and optimize the use of animal models.
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Affiliation(s)
- Alessandra Breschi
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain
- Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain
| | - Thomas R Gingeras
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11742, USA
| | - Roderic Guigó
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain
- Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain
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207
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Villanueva‐Cañas JL, Rech GE, Cara MAR, González J. Beyond
SNP
s: how to detect selection on transposable element insertions. Methods Ecol Evol 2017. [DOI: 10.1111/2041-210x.12781] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
| | - Gabriel E. Rech
- Institute of Evolutionary Biology (CSIC‐Universitat Pompeu Fabra) Barcelona Spain
| | - Maria Angeles Rodriguez Cara
- Ecoanthropology and Ethnobiology Laboratory, UMR 7206, CNRS/MNHN/Universite Paris 7 Museum National d'HistoireNaturelle F‐75116 Paris France
| | - Josefa González
- Institute of Evolutionary Biology (CSIC‐Universitat Pompeu Fabra) Barcelona Spain
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208
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Yang ZP, Ma HS, Wang SS, Wang L, Liu T. LAMC1 mRNA promotes malignancy of hepatocellular carcinoma cells by competing for MicroRNA-124 binding with CD151. IUBMB Life 2017; 69:595-605. [PMID: 28524360 DOI: 10.1002/iub.1642] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 04/27/2017] [Indexed: 01/02/2023]
Abstract
Specific RNAs can function as sinks for endogenous miRNAs, known as competing endogenous RNAs (ceRNAs). Here, we confirm a miR-124 mediated ceRNA crosstalk between LAMC1 and CD151 in hepatocellular carcinoma (HCC). miR-124 negatively regulates LAMC1 expression through two miRNA binding sites within its 3' untranslated region (3'UTR) and suppresses migration and invasion of HCC cells through regulating LAMC1. The wild type LAMC1 miRNA response elements (MREs) facilitate expression of CD151, and this regulation is miR-124 dependent. In clinical hepatic tissues, LAMC1 and CD151 mRNAs exhibit positive correlation. Importantly, LAMC1 MREs promote HCC malignancy by absorbing miR-124 and by assisting CD151 expression. We conclude that LAMC1 mRNA acts as a trans regulator to stimulate CD151 expression by competing for miR-124 binding in HCC cells. © 2017 IUBMB Life, 69(8):595-605, 2017.
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Affiliation(s)
- Zhan-Po Yang
- Department of Urology, Tianjin First Central Hospital, Tianjin, China
| | - Hong-Shun Ma
- Department of Urology, Tianjin First Central Hospital, Tianjin, China
| | - Shu-Sen Wang
- Key Laboratory for Critical Care Medicine of the Ministry of Health, Tianjin First Central Hospital, Tianjin, China.,Tianjin Key Laboratory for Organ Transplantation, Tianjin First Central Hospital, Tianjin, China.,Tianjin Organ Transplantation Research Center, Tianjin First Central Hospital, Tianjin, China
| | - Le Wang
- Key Laboratory for Critical Care Medicine of the Ministry of Health, Tianjin First Central Hospital, Tianjin, China
| | - Tao Liu
- Key Laboratory for Critical Care Medicine of the Ministry of Health, Tianjin First Central Hospital, Tianjin, China.,Tianjin Key Laboratory for Organ Transplantation, Tianjin First Central Hospital, Tianjin, China.,Tianjin Organ Transplantation Research Center, Tianjin First Central Hospital, Tianjin, China
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209
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Zovoilis A, Cifuentes-Rojas C, Chu HP, Hernandez AJ, Lee JT. Destabilization of B2 RNA by EZH2 Activates the Stress Response. Cell 2017; 167:1788-1802.e13. [PMID: 27984727 DOI: 10.1016/j.cell.2016.11.041] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 10/03/2016] [Accepted: 11/22/2016] [Indexed: 12/12/2022]
Abstract
More than 98% of the mammalian genome is noncoding, and interspersed transposable elements account for ∼50% of noncoding space. Here, we demonstrate that a specific interaction between the polycomb protein EZH2 and RNA made from B2 SINE retrotransposons controls stress-responsive genes in mouse cells. In the heat-shock model, B2 RNA binds stress genes and suppresses their transcription. Upon stress, EZH2 is recruited and triggers cleavage of B2 RNA. B2 degradation in turn upregulates stress genes. Evidence indicates that B2 RNA operates as a "speed bump" against advancement of RNA polymerase II, and temperature stress releases the brakes on transcriptional elongation. These data attribute a new function to EZH2 that is independent of its histone methyltransferase activity and reconcile how EZH2 can be associated with both gene repression and activation. Our study reveals that EZH2 and B2 together control activation of a large network of genes involved in thermal stress.
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Affiliation(s)
- Athanasios Zovoilis
- Howard Hughes Medical Institute; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Catherine Cifuentes-Rojas
- Howard Hughes Medical Institute; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Hsueh-Ping Chu
- Howard Hughes Medical Institute; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Alfredo J Hernandez
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Jeannie T Lee
- Howard Hughes Medical Institute; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02114, USA.
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210
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Loreto ELS, Pereira CM. Somatizing the transposons action. Mob Genet Elements 2017; 7:1-9. [PMID: 28580196 DOI: 10.1080/2159256x.2017.1314236] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/28/2017] [Accepted: 03/28/2017] [Indexed: 01/22/2023] Open
Abstract
The somatic mobilization of transposable elements is more common than previously thought. In this review we discuss how the intensity and the biologic consequences of somatic mobilization are dependent on the transposable elements landscapes of each genome, and on the "momentum" of each particular TE with respect to the mechanisms that control its transposition and the possibility to escape this control. Additionally, the biologic consequences of somatic mobilization vary among organisms that show an early separation between the germline and somatic cells and those organisms that do not exhibit this separation or that reproduce asexually. In the former, somatic transposition can be involved in phenotypic plasticity, detrimental conditions such as disease, or processes such as aging. For the organisms without separation between the germ and soma, somatic mobilization can be a source of genetic variability.
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Affiliation(s)
- Elgion L S Loreto
- Department of Biochemistry and Molecular Biology, University of Santa Maria, Santa Maria, RS, Brazil
| | - Camila Moura Pereira
- Postgraduate Programme in Animal Biodiversity, University of Santa Maria, Santa Maria, RS, Brazil
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211
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Sundaram V, Choudhary MNK, Pehrsson E, Xing X, Fiore C, Pandey M, Maricque B, Udawatta M, Ngo D, Chen Y, Paguntalan A, Ray T, Hughes A, Cohen BA, Wang T. Functional cis-regulatory modules encoded by mouse-specific endogenous retrovirus. Nat Commun 2017; 8:14550. [PMID: 28348391 PMCID: PMC5379053 DOI: 10.1038/ncomms14550] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 01/11/2017] [Indexed: 01/30/2023] Open
Abstract
Cis-regulatory modules contain multiple transcription factor (TF)-binding sites and integrate the effects of each TF to control gene expression in specific cellular contexts. Transposable elements (TEs) are uniquely equipped to deposit their regulatory sequences across a genome, which could also contain cis-regulatory modules that coordinate the control of multiple genes with the same regulatory logic. We provide the first evidence of mouse-specific TEs that encode a module of TF-binding sites in mouse embryonic stem cells (ESCs). The majority (77%) of the individual TEs tested exhibited enhancer activity in mouse ESCs. By mutating individual TF-binding sites within the TE, we identified a module of TF-binding motifs that cooperatively enhanced gene expression. Interestingly, we also observed the same motif module in the in silico constructed ancestral TE that also acted cooperatively to enhance gene expression. Our results suggest that ancestral TE insertions might have brought in cis-regulatory modules into the mouse genome.
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Affiliation(s)
- Vasavi Sundaram
- Division of Biological and Biomedical Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Mayank N. K. Choudhary
- Division of Biological and Biomedical Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Erica Pehrsson
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Xiaoyun Xing
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Christopher Fiore
- Division of Biological and Biomedical Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Manishi Pandey
- Division of Biological and Biomedical Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Brett Maricque
- Division of Biological and Biomedical Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Methma Udawatta
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Duc Ngo
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Yujie Chen
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Asia Paguntalan
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Tammy Ray
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Ava Hughes
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Barak A. Cohen
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
| | - Ting Wang
- Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, Missouri 63110, USA
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212
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Kauzlaric A, Ecco G, Cassano M, Duc J, Imbeault M, Trono D. The mouse genome displays highly dynamic populations of KRAB-zinc finger protein genes and related genetic units. PLoS One 2017; 12:e0173746. [PMID: 28334004 PMCID: PMC5363842 DOI: 10.1371/journal.pone.0173746] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 02/24/2017] [Indexed: 12/13/2022] Open
Abstract
KRAB-containing poly-zinc finger proteins (KZFPs) constitute the largest family of transcription factors encoded by mammalian genomes, and growing evidence indicates that they fulfill functions critical to both embryonic development and maintenance of adult homeostasis. KZFP genes underwent broad and independent waves of expansion in many higher vertebrates lineages, yet comprehensive studies of members harbored by a given species are scarce. Here we present a thorough analysis of KZFP genes and related units in the murine genome. We first identified about twice as many elements than previously annotated as either KZFP genes or pseudogenes, notably by assigning to this family an entity formerly considered as a large group of Satellite repeats. We then could delineate an organization in clusters distributed throughout the genome, with signs of recombination, translocation, duplication and seeding of new sites by retrotransposition of KZFP genes and related genetic units (KZFP/rGUs). Moreover, we harvested evidence indicating that closely related paralogs had evolved through both drifting and shifting of sequences encoding for zinc finger arrays. Finally, we could demonstrate that the KAP1-SETDB1 repressor complex tames the expression of KZFP/rGUs within clusters, yet that the primary targets of this regulation are not the KZFP/rGUs themselves but enhancers contained in neighboring endogenous retroelements and that, underneath, KZFPs conserve highly individualized patterns of expression.
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Affiliation(s)
- Annamaria Kauzlaric
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Gabriela Ecco
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Marco Cassano
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Julien Duc
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Michael Imbeault
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Didier Trono
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- * E-mail:
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213
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Simplification, Innateness, and the Absorption of Meaning from Context: How Novelty Arises from Gradual Network Evolution. Evol Biol 2017; 44:145-189. [PMID: 28572690 PMCID: PMC5429377 DOI: 10.1007/s11692-017-9407-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 01/06/2017] [Indexed: 02/07/2023]
Abstract
How does new genetic information arise? Traditional thinking holds that mutation happens by accident and then spreads in the population by either natural selection or random genetic drift. There have been at least two fundamental conceptual problems with imagining an alternative. First, it seemed that the only alternative is a mutation that responds "smartly" to the immediate environment; but in complex multicellulars, it is hard to imagine how this could be implemented. Second, if there were mechanisms of mutation that "knew" what genetic changes would be favored in a given environment, this would have only begged the question of how they acquired that particular knowledge to begin with. This paper offers an alternative that avoids these problems. It holds that mutational mechanisms act on information that is in the genome, based on considerations of simplicity, parsimony, elegance, etc. (which are different than fitness considerations). This simplification process, under the performance pressure exerted by selection, not only leads to the improvement of adaptations but also creates elements that have the capacity to serve in new contexts they were not originally selected for. Novelty, then, arises at the system level from emergent interactions between such elements. Thus, mechanistically driven mutation neither requires Lamarckian transmission nor closes the door on novelty, because the changes it implements interact with one another globally in surprising and beneficial ways. Finally, I argue, for example, that genes used together are fused together; that simplification leads to complexity; and that evolution and learning are conceptually linked.
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214
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Ramsay L, Marchetto MC, Caron M, Chen SH, Busche S, Kwan T, Pastinen T, Gage FH, Bourque G. Conserved expression of transposon-derived non-coding transcripts in primate stem cells. BMC Genomics 2017; 18:214. [PMID: 28245871 PMCID: PMC5331655 DOI: 10.1186/s12864-017-3568-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 02/07/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND A significant portion of expressed non-coding RNAs in human cells is derived from transposable elements (TEs). Moreover, it has been shown that various long non-coding RNAs (lncRNAs), which come from the human endogenous retrovirus subfamily H (HERVH), are not only expressed but required for pluripotency in human embryonic stem cells (hESCs). RESULTS To identify additional TE-derived functional non-coding transcripts, we generated RNA-seq data from induced pluripotent stem cells (iPSCs) of four primate species (human, chimpanzee, gorilla, and rhesus) and searched for transcripts whose expression was conserved. We observed that about 30% of TE instances expressed in human iPSCs had orthologous TE instances that were also expressed in chimpanzee and gorilla. Notably, our analysis revealed a number of repeat families with highly conserved expression profiles including HERVH but also MER53, which is known to be the source of a placental-specific family of microRNAs (miRNAs). We also identified a number of repeat families from all classes of TEs, including MLT1-type and Tigger families, that contributed a significant amount of sequence to primate lncRNAs whose expression was conserved. CONCLUSIONS Together, these results describe TE families and TE-derived lncRNAs whose conserved expression patterns can be used to identify what are likely functional TE-derived non-coding transcripts in primate iPSCs.
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Affiliation(s)
- LeeAnn Ramsay
- Department of Human Genetics, McGill University, Dr Penfield Avenue, Montreal, H3A 1B1, Canada
| | - Maria C Marchetto
- Lab of Genetics, Salk Institute for Biological Studies, 10010 N Torrey Pines Rd, La Jolla, CA 92037, USA
| | - Maxime Caron
- Department of Human Genetics, McGill University, Dr Penfield Avenue, Montreal, H3A 1B1, Canada
- McGill University and Genome Quebec Innovation Centre, 740 Dr Penfield Avenue, Montreal, H3A 1A4, Canada
| | - Shu-Huang Chen
- McGill University and Genome Quebec Innovation Centre, 740 Dr Penfield Avenue, Montreal, H3A 1A4, Canada
| | - Stephan Busche
- McGill University and Genome Quebec Innovation Centre, 740 Dr Penfield Avenue, Montreal, H3A 1A4, Canada
| | - Tony Kwan
- Department of Human Genetics, McGill University, Dr Penfield Avenue, Montreal, H3A 1B1, Canada
- McGill University and Genome Quebec Innovation Centre, 740 Dr Penfield Avenue, Montreal, H3A 1A4, Canada
| | - Tomi Pastinen
- Department of Human Genetics, McGill University, Dr Penfield Avenue, Montreal, H3A 1B1, Canada
- McGill University and Genome Quebec Innovation Centre, 740 Dr Penfield Avenue, Montreal, H3A 1A4, Canada
| | - Fred H Gage
- Lab of Genetics, Salk Institute for Biological Studies, 10010 N Torrey Pines Rd, La Jolla, CA 92037, USA
| | - Guillaume Bourque
- Department of Human Genetics, McGill University, Dr Penfield Avenue, Montreal, H3A 1B1, Canada.
- McGill University and Genome Quebec Innovation Centre, 740 Dr Penfield Avenue, Montreal, H3A 1A4, Canada.
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215
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Casa V, Runfola V, Micheloni S, Aziz A, Dilworth FJ, Gabellini D. Polycomb repressive complex 1 provides a molecular explanation for repeat copy number dependency in FSHD muscular dystrophy. Hum Mol Genet 2017; 26:753-767. [PMID: 28040729 PMCID: PMC5409123 DOI: 10.1093/hmg/ddw426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 12/15/2016] [Indexed: 11/13/2022] Open
Abstract
Repression of repetitive elements is crucial to preserve genome integrity and has been traditionally ascribed to constitutive heterochromatin pathways. FacioScapuloHumeral Muscular Dystrophy (FSHD), one of the most common myopathies, is characterized by a complex interplay of genetic and epigenetic events. The main FSHD form is linked to a reduced copy number of the D4Z4 macrosatellite repeat on 4q35, causing loss of silencing and aberrant expression of the D4Z4-embedded DUX4 gene leading to disease. By an unknown mechanism, D4Z4 copy-number correlates with FSHD phenotype. Here we show that the DUX4 proximal promoter (DUX4p) is sufficient to nucleate the enrichment of both constitutive and facultative heterochromatin components and to mediate a copy-number dependent gene silencing. We found that both the CpG/GC dense DNA content and the repetitive nature of DUX4p arrays are important for their repressive ability. We showed that DUX4p mediates a copy number-dependent Polycomb Repressive Complex 1 (PRC1) recruitment, which is responsible for the copy-number dependent gene repression. Overall, we directly link genetic and epigenetic defects in FSHD by proposing a novel molecular explanation for the copy number-dependency in FSHD pathogenesis, and offer insight into the molecular functions of repeats in chromatin regulation.
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Affiliation(s)
- Valentina Casa
- Gene Expression and Muscular Dystrophy Unit, Division of Regenerative Medicine, IRCCS San Raffaele Scientific Institute, Milan 20132, Italy.,Università Vita-Salute San Raffaele, Milan 20132, Italy
| | - Valeria Runfola
- Gene Expression and Muscular Dystrophy Unit, Division of Regenerative Medicine, IRCCS San Raffaele Scientific Institute, Milan 20132, Italy
| | - Stefano Micheloni
- Gene Expression and Muscular Dystrophy Unit, Division of Regenerative Medicine, IRCCS San Raffaele Scientific Institute, Milan 20132, Italy
| | - Arif Aziz
- The Sprott Center for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1Y 4E9, Canada
| | - F Jeffrey Dilworth
- The Sprott Center for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1Y 4E9, Canada
| | - Davide Gabellini
- Gene Expression and Muscular Dystrophy Unit, Division of Regenerative Medicine, IRCCS San Raffaele Scientific Institute, Milan 20132, Italy.,Dulbecco Telethon Institute, Milan 20132, Italy
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216
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Schumann U, Lee J, Kazan K, Ayliffe M, Wang MB. DNA-Demethylase Regulated Genes Show Methylation-Independent Spatiotemporal Expression Patterns. FRONTIERS IN PLANT SCIENCE 2017; 8:1449. [PMID: 28894455 PMCID: PMC5581395 DOI: 10.3389/fpls.2017.01449] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 08/04/2017] [Indexed: 05/12/2023]
Abstract
Recent research has indicated that a subset of defense-related genes is downregulated in the Arabidopsis DNA demethylase triple mutant rdd (ros1 dml2 dml3) resulting in increased susceptibility to the fungal pathogen Fusarium oxysporum. In rdd plants these downregulated genes contain hypermethylated transposable element sequences (TE) in their promoters, suggesting that this methylation represses gene expression in the mutant and that these sequences are actively demethylated in wild-type plants to maintain gene expression. In this study, the tissue-specific and pathogen-inducible expression patterns of rdd-downregulated genes were investigated and the individual role of ROS1, DML2, and DML3 demethylases in these spatiotemporal regulation patterns was determined. Large differences in defense gene expression were observed between pathogen-infected and uninfected tissues and between root and shoot tissues in both WT and rdd plants, however, only subtle changes in promoter TE methylation patterns occurred. Therefore, while TE hypermethylation caused decreased gene expression in rdd plants it did not dramatically effect spatiotemporal gene regulation, suggesting that this latter regulation is largely methylation independent. Analysis of ros1-3, dml2-1, and dml3-1 single gene mutant lines showed that promoter TE hypermethylation and defense-related gene repression was predominantly, but not exclusively, due to loss of ROS1 activity. These data demonstrate that DNA demethylation of TE sequences, largely by ROS1, promotes defense-related gene expression but does not control spatiotemporal expression in Arabidopsis. Summary: Ros1-mediated DNA demethylation of promoter transposable elements is essential for activation of defense-related gene expression in response to fungal infection in Arabidopsis thaliana.
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Affiliation(s)
- Ulrike Schumann
- CSIRO Agriculture and Food, CanberraACT, Australia
- *Correspondence: Ming-Bo Wang, Ulrike Schumann,
| | - Joanne Lee
- CSIRO Agriculture and Food, CanberraACT, Australia
| | - Kemal Kazan
- CSIRO Agriculture and Food, Queensland Bioscience Precinct, St. LuciaQLD, Australia
| | | | - Ming-Bo Wang
- CSIRO Agriculture and Food, CanberraACT, Australia
- *Correspondence: Ming-Bo Wang, Ulrike Schumann,
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217
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Chuong EB, Elde NC, Feschotte C. Regulatory activities of transposable elements: from conflicts to benefits. Nat Rev Genet 2016; 18:71-86. [PMID: 27867194 DOI: 10.1038/nrg.2016.139] [Citation(s) in RCA: 777] [Impact Index Per Article: 97.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Transposable elements (TEs) are a prolific source of tightly regulated, biochemically active non-coding elements, such as transcription factor-binding sites and non-coding RNAs. Many recent studies reinvigorate the idea that these elements are pervasively co-opted for the regulation of host genes. We argue that the inherent genetic properties of TEs and the conflicting relationships with their hosts facilitate their recruitment for regulatory functions in diverse genomes. We review recent findings supporting the long-standing hypothesis that the waves of TE invasions endured by organisms for eons have catalysed the evolution of gene-regulatory networks. We also discuss the challenges of dissecting and interpreting the phenotypic effect of regulatory activities encoded by TEs in health and disease.
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Affiliation(s)
- Edward B Chuong
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84103, USA
| | - Nels C Elde
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84103, USA
| | - Cédric Feschotte
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84103, USA
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218
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de la Rica L, Deniz Ö, Cheng KCL, Todd CD, Cruz C, Houseley J, Branco MR. TET-dependent regulation of retrotransposable elements in mouse embryonic stem cells. Genome Biol 2016; 17:234. [PMID: 27863519 PMCID: PMC5116139 DOI: 10.1186/s13059-016-1096-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 11/01/2016] [Indexed: 12/21/2022] Open
Abstract
Background Ten-eleven translocation (TET) enzymes oxidise DNA methylation as part of an active demethylation pathway. Despite extensive research into the role of TETs in genome regulation, little is known about their effect on transposable elements (TEs), which make up nearly half of the mouse and human genomes. Epigenetic mechanisms controlling TEs have the potential to affect their mobility and to drive the co-adoption of TEs for the benefit of the host. Results We performed a detailed investigation of the role of TET enzymes in the regulation of TEs in mouse embryonic stem cells (ESCs). We find that TET1 and TET2 bind multiple TE classes that harbour a variety of epigenetic signatures indicative of different functional roles. TETs co-bind with pluripotency factors to enhancer-like TEs that interact with highly expressed genes in ESCs whose expression is partly maintained by TET2-mediated DNA demethylation. TETs and 5-hydroxymethylcytosine (5hmC) are also strongly enriched at the 5′ UTR of full-length, evolutionarily young LINE-1 elements, a pattern that is conserved in human ESCs. TETs drive LINE-1 demethylation, but surprisingly, LINE-1s are kept repressed through additional TET-dependent activities. We find that the SIN3A co-repressive complex binds to LINE-1s, ensuring their repression in a TET1-dependent manner. Conclusions Our data implicate TET enzymes in the evolutionary dynamics of TEs, both in the context of exaptation processes and of retrotransposition control. The dual role of TET action on LINE-1s may reflect the evolutionary battle between TEs and the host. Electronic supplementary material The online version of this article (doi:10.1186/s13059-016-1096-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lorenzo de la Rica
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London, E1 2AT, UK
| | - Özgen Deniz
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London, E1 2AT, UK
| | - Kevin C L Cheng
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London, E1 2AT, UK
| | - Christopher D Todd
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London, E1 2AT, UK
| | - Cristina Cruz
- Epigenetics Programme, Babraham Institute, Cambridge, CB22 3AT, UK
| | | | - Miguel R Branco
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London, E1 2AT, UK.
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219
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Long HK, Prescott SL, Wysocka J. Ever-Changing Landscapes: Transcriptional Enhancers in Development and Evolution. Cell 2016; 167:1170-1187. [PMID: 27863239 PMCID: PMC5123704 DOI: 10.1016/j.cell.2016.09.018] [Citation(s) in RCA: 564] [Impact Index Per Article: 70.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/24/2016] [Accepted: 09/07/2016] [Indexed: 12/27/2022]
Abstract
A class of cis-regulatory elements, called enhancers, play a central role in orchestrating spatiotemporally precise gene-expression programs during development. Consequently, divergence in enhancer sequence and activity is thought to be an important mediator of inter- and intra-species phenotypic variation. Here, we give an overview of emerging principles of enhancer function, current models of enhancer architecture, genomic substrates from which enhancers emerge during evolution, and the influence of three-dimensional genome organization on long-range gene regulation. We discuss intricate relationships between distinct elements within complex regulatory landscapes and consider their potential impact on specificity and robustness of transcriptional regulation.
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Affiliation(s)
- Hannah K Long
- Department of Chemical and Systems Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Institute of Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Sara L Prescott
- Department of Chemical and Systems Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Department of Developmental Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Joanna Wysocka
- Department of Chemical and Systems Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Institute of Stem Cell Biology and Regenerative Medicine, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Department of Developmental Biology, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford School of Medicine, Stanford University, Stanford, CA 94305, USA.
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220
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Abstract
Despite often being classified as selfish or junk DNA, transposable elements (TEs) are a group of abundant genetic sequences that have a significant impact on mammalian development and genome regulation. In recent years, our understanding of how pre-existing TEs affect genome architecture, gene regulatory networks and protein function during mammalian embryogenesis has dramatically expanded. In addition, the mobilization of active TEs in selected cell types has been shown to generate genetic variation during development and in fully differentiated tissues. Importantly, the ongoing domestication and evolution of TEs appears to provide a rich source of regulatory elements, functional modules and genetic variation that fuels the evolution of mammalian developmental processes. Here, we review the functional impact that TEs exert on mammalian developmental processes and discuss how the somatic activity of TEs can influence gene regulatory networks.
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Affiliation(s)
- Jose L Garcia-Perez
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
- Department of Genomic Medicine, GENYO, Centre for Genomics & Oncology (Pfizer - University of Granada & Andalusian Regional Government), PTS Granada, Avda. de la Ilustración 114, Granada 18016, Spain
| | - Thomas J Widmann
- Department of Genomic Medicine, GENYO, Centre for Genomics & Oncology (Pfizer - University of Granada & Andalusian Regional Government), PTS Granada, Avda. de la Ilustración 114, Granada 18016, Spain
| | - Ian R Adams
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
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221
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Ernst J, Melnikov A, Zhang X, Wang L, Rogov P, Mikkelsen TS, Kellis M. Genome-scale high-resolution mapping of activating and repressive nucleotides in regulatory regions. Nat Biotechnol 2016; 34:1180-1190. [PMID: 27701403 PMCID: PMC5125825 DOI: 10.1038/nbt.3678] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 08/16/2016] [Indexed: 02/07/2023]
Abstract
Massively parallel reporter assays (MPRAs) enable nucleotide-resolution dissection of transcriptional regulatory regions, such as enhancers, but only few regions at a time. Here we present a combined experimental and computational approach, Systematic high-resolution activation and repression profiling with reporter tiling using MPRA (Sharpr-MPRA), that allows high-resolution analysis of thousands of regions simultaneously. Sharpr-MPRA combines dense tiling of overlapping MPRA constructs with a probabilistic graphical model to recognize functional regulatory nucleotides, and to distinguish activating and repressive nucleotides, using their inferred contribution to reporter gene expression. We used Sharpr-MPRA to test 4.6 million nucleotides spanning 15,000 putative regulatory regions tiled at 5-nucleotide resolution in two human cell types. Our results recovered known cell-type-specific regulatory motifs and evolutionarily conserved nucleotides, and distinguished known activating and repressive motifs. Our results also showed that endogenous chromatin state and DNA accessibility are both predictive of regulatory function in reporter assays, identified retroviral elements with activating roles, and uncovered 'attenuator' motifs with repressive roles in active chromatin.
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Affiliation(s)
- Jason Ernst
- Department of Biological Chemistry, University of California, Los Angeles, California, USA
- Computer Science Department, University of California, Los Angeles, California, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at University of California Los Angeles, Los Angeles, California, USA
- Jonsson Comprehensive Cancer Center, University of California, Los Angeles, California, USA
- Molecular Biology Institute, University of California, Los Angeles, California, USA
| | - Alexandre Melnikov
- Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts, USA
| | - Xiaolan Zhang
- Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts, USA
| | - Li Wang
- Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts, USA
| | - Peter Rogov
- Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts, USA
| | - Tarjei S. Mikkelsen
- Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts, USA
| | - Manolis Kellis
- Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts, USA
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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222
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Nishihara H, Kobayashi N, Kimura-Yoshida C, Yan K, Bormuth O, Ding Q, Nakanishi A, Sasaki T, Hirakawa M, Sumiyama K, Furuta Y, Tarabykin V, Matsuo I, Okada N. Coordinately Co-opted Multiple Transposable Elements Constitute an Enhancer for wnt5a Expression in the Mammalian Secondary Palate. PLoS Genet 2016; 12:e1006380. [PMID: 27741242 PMCID: PMC5065162 DOI: 10.1371/journal.pgen.1006380] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/21/2016] [Indexed: 11/18/2022] Open
Abstract
Acquisition of cis-regulatory elements is a major driving force of evolution, and there are several examples of developmental enhancers derived from transposable elements (TEs). However, it remains unclear whether one enhancer element could have been produced via cooperation among multiple, yet distinct, TEs during evolution. Here we show that an evolutionarily conserved genomic region named AS3_9 comprises three TEs (AmnSINE1, X6b_DNA and MER117), inserted side-by-side, and functions as a distal enhancer for wnt5a expression during morphogenesis of the mammalian secondary palate. Functional analysis of each TE revealed step-by-step retroposition/transposition and co-option together with acquisition of a binding site for Msx1 for its full enhancer function during mammalian evolution. The present study provides a new perspective suggesting that a huge variety of TEs, in combination, could have accelerated the diversity of cis-regulatory elements involved in morphological evolution.
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Affiliation(s)
- Hidenori Nishihara
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, Kanagawa, Japan
| | - Naoki Kobayashi
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, Kanagawa, Japan
| | - Chiharu Kimura-Yoshida
- Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka Prefectural Hospital Organization, Izumi, Osaka, Japan
| | - Kuo Yan
- Institute of Cell Biology and Neurobiology, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Olga Bormuth
- Institute of Cell Biology and Neurobiology, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Qiong Ding
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, Kanagawa, Japan
| | - Akiko Nakanishi
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, Kanagawa, Japan
| | - Takeshi Sasaki
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, Kanagawa, Japan
| | - Mika Hirakawa
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, Japan
| | - Kenta Sumiyama
- National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Yasuhide Furuta
- Animal Resource Development Unit, RIKEN Center for Life Science Technologies, Chuou-ku, Kobe, Japan
- Genetic Engineering Team, RIKEN Center for Life Science Technologies, Chuou-ku, Kobe, Japan
| | - Victor Tarabykin
- Institute of Cell Biology and Neurobiology, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Isao Matsuo
- Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka Prefectural Hospital Organization, Izumi, Osaka, Japan
| | - Norihiro Okada
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, Kanagawa, Japan
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
- Foundation for Advancement of International Science, Tsukuba, Japan
- * E-mail: ,
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223
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Warren IA, Naville M, Chalopin D, Levin P, Berger CS, Galiana D, Volff JN. Evolutionary impact of transposable elements on genomic diversity and lineage-specific innovation in vertebrates. Chromosome Res 2016; 23:505-31. [PMID: 26395902 DOI: 10.1007/s10577-015-9493-5] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Since their discovery, a growing body of evidence has emerged demonstrating that transposable elements are important drivers of species diversity. These mobile elements exhibit a great variety in structure, size and mechanisms of transposition, making them important putative actors in organism evolution. The vertebrates represent a highly diverse and successful lineage that has adapted to a wide range of different environments. These animals also possess a rich repertoire of transposable elements, with highly diverse content between lineages and even between species. Here, we review how transposable elements are driving genomic diversity and lineage-specific innovation within vertebrates. We discuss the large differences in TE content between different vertebrate groups and then go on to look at how they affect organisms at a variety of levels: from the structure of chromosomes to their involvement in the regulation of gene expression, as well as in the formation and evolution of non-coding RNAs and protein-coding genes. In the process of doing this, we highlight how transposable elements have been involved in the evolution of some of the key innovations observed within the vertebrate lineage, driving the group's diversity and success.
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Affiliation(s)
- Ian A Warren
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Magali Naville
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Domitille Chalopin
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France.,Department of Genetics, University of Georgia, Athens, Georgia, 30602, USA
| | - Perrine Levin
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Chloé Suzanne Berger
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Delphine Galiana
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Jean-Nicolas Volff
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France.
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224
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Abstract
The germ track is the cellular path by which genes are transmitted to future generations whereas somatic cells die with their body and do not leave direct descendants. Transposable elements (TEs) evolve to be silent in somatic cells but active in the germ track. Thus, the performance of most bodily functions by a sequestered soma reduces organismal costs of TEs. Flexible forms of gene regulation are permissible in the soma because of the self-imposed silence of TEs, but strict licensing of transcription and translation is maintained in the germ track to control proliferation of TEs. Delayed zygotic genome activation (ZGA) and maternally inherited germ granules are adaptations that enhance germ-track security. Mammalian embryos exhibit very early ZGA associated with extensive mobilization of retroelements. This window of vulnerability to retrotransposition in early embryos is an indirect consequence of evolutionary conflicts within the mammalian genome over postzygotic maternal provisioning.
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Affiliation(s)
- David Haig
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.
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225
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Bouttier M, Laperriere D, Memari B, Mangiapane J, Fiore A, Mitchell E, Verway M, Behr MA, Sladek R, Barreiro LB, Mader S, White JH. Alu repeats as transcriptional regulatory platforms in macrophage responses to M. tuberculosis infection. Nucleic Acids Res 2016; 44:10571-10587. [PMID: 27604870 PMCID: PMC5159539 DOI: 10.1093/nar/gkw782] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 12/19/2022] Open
Abstract
To understand the epigenetic regulation of transcriptional response of macrophages during early-stage M. tuberculosis (Mtb) infection, we performed ChIPseq analysis of H3K4 monomethylation (H3K4me1), a marker of poised or active enhancers. De novo H3K4me1 peaks in infected cells were associated with genes implicated in host defenses and apoptosis. Our analysis revealed that 40% of de novo regions contained human/primate-specific Alu transposable elements, enriched in the AluJ and S subtypes. These contained several transcription factor binding sites, including those for members of the MEF2 and ATF families, and LXR and RAR nuclear receptors, all of which have been implicated in macrophage differentiation, survival, and responses to stress and infection. Combining bioinformatics, molecular genetics, and biochemical approaches, we linked genes adjacent to H3K4me1-associated Alu repeats to macrophage metabolic responses against Mtb infection. In particular, we show that LXRα signaling, which reduced Mtb viability 18-fold by altering cholesterol metabolism and enhancing macrophage apoptosis, can be initiated at response elements present in Alu repeats. These studies decipher the mechanism of early macrophage transcriptional responses to Mtb, highlighting the role of Alu element transposition in shaping human transcription programs during innate immunity.
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Affiliation(s)
- Manuella Bouttier
- Department of Physiology, Montréal, Québec, Canada .,McGill University, Montréal, Québec, Canada
| | - David Laperriere
- Département de Biochimie, Montréal, Québec, Canada.,Institut de Recherche en Immunologie et Cancérologie (IRIC), Montréal, Québec, Canada.,Université de Montréal, Montréal, Québec, Canada
| | - Babak Memari
- Department of Physiology, Montréal, Québec, Canada.,McGill University, Montréal, Québec, Canada
| | - Joseph Mangiapane
- Department of Physiology, Montréal, Québec, Canada.,McGill University, Montréal, Québec, Canada
| | - Amanda Fiore
- Department of Physiology, Montréal, Québec, Canada.,McGill University, Montréal, Québec, Canada
| | - Eric Mitchell
- Department of Physiology, Montréal, Québec, Canada.,McGill University, Montréal, Québec, Canada
| | - Mark Verway
- Department of Physiology, Montréal, Québec, Canada.,McGill University, Montréal, Québec, Canada
| | - Marcel A Behr
- McGill University, Montréal, Québec, Canada.,Division of Infectious Diseases and Medical Microbiology, Montréal, Québec, Canada.,McGill International TB Centre, Montréal, Québec, Canada
| | - Robert Sladek
- McGill University, Montréal, Québec, Canada.,School of Computer Science, Montréal, Québec, Canada.,Genome Quebec Innovation Centre, Montréal, Québec, Canada
| | - Luis B Barreiro
- Université de Montréal, Montréal, Québec, Canada.,Department of Pediatrics, Montréal, Québec, Canada
| | - Sylvie Mader
- Département de Biochimie, Montréal, Québec, Canada.,Institut de Recherche en Immunologie et Cancérologie (IRIC), Montréal, Québec, Canada.,Université de Montréal, Montréal, Québec, Canada
| | - John H White
- Department of Physiology, Montréal, Québec, Canada .,McGill University, Montréal, Québec, Canada.,Department of Medecine, Montréal, Québec, Canada
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226
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Janoušek V, Laukaitis CM, Yanchukov A, Karn RC. The Role of Retrotransposons in Gene Family Expansions in the Human and Mouse Genomes. Genome Biol Evol 2016; 8:2632-50. [PMID: 27503295 PMCID: PMC5631067 DOI: 10.1093/gbe/evw192] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Retrotransposons comprise a large portion of mammalian genomes. They contribute to structural changes and more importantly to gene regulation. The expansion and diversification of gene families have been implicated as sources of evolutionary novelties. Given the roles retrotransposons play in genomes, their contribution to the evolution of gene families warrants further exploration. In this study, we found a significant association between two major retrotransposon classes, LINEs and LTRs, and lineage-specific gene family expansions in both the human and mouse genomes. The distribution and diversity differ between LINEs and LTRs, suggesting that each has a distinct involvement in gene family expansion. LTRs are associated with open chromatin sites surrounding the gene families, supporting their involvement in gene regulation, whereas LINEs may play a structural role promoting gene duplication. Our findings also suggest that gene family expansions, especially in the mouse genome, undergo two phases. The first phase is characterized by elevated deposition of LTRs and their utilization in reshaping gene regulatory networks. The second phase is characterized by rapid gene family expansion due to continuous accumulation of LINEs and it appears that, in some instances at least, this could become a runaway process. We provide an example in which this has happened and we present a simulation supporting the possibility of the runaway process. Altogether we provide evidence of the contribution of retrotransposons to the expansion and evolution of gene families. Our findings emphasize the putative importance of these elements in diversification and adaptation in the human and mouse lineages.
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Affiliation(s)
- Václav Janoušek
- Department of Zoology, Faculty of Science, Charles University in Prague, Prague, Czech Republic Institute of Vertebrate Biology, ASCR, Brno, Czech Republic
| | | | - Alexey Yanchukov
- Institute of Vertebrate Biology, ASCR, Brno, Czech Republic Department of Biology, Faculty of Arts and Sciences, Bülent Ecevit University, Zonguldak, Turkey
| | - Robert C Karn
- Department of Medicine, College of Medicine, University of Arizona
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227
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Pugacheva EM, Teplyakov E, Wu Q, Li J, Chen C, Meng C, Liu J, Robinson S, Loukinov D, Boukaba A, Hutchins AP, Lobanenkov V, Strunnikov A. The cancer-associated CTCFL/BORIS protein targets multiple classes of genomic repeats, with a distinct binding and functional preference for humanoid-specific SVA transposable elements. Epigenetics Chromatin 2016; 9:35. [PMID: 27588042 PMCID: PMC5007689 DOI: 10.1186/s13072-016-0084-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/18/2016] [Indexed: 12/20/2022] Open
Abstract
Background A common aberration in cancer is the activation of germline-specific proteins. The DNA-binding proteins among them could generate novel chromatin states, not found in normal cells. The germline-specific transcription factor BORIS/CTCFL, a paralog of chromatin architecture protein CTCF, is often erroneously activated in cancers and rewires the epigenome for the germline-like transcription program. Another common feature of malignancies is the changed expression and epigenetic states of genomic repeats, which could alter the transcription of neighboring genes and cause somatic mutations upon transposition. The role of BORIS in transposable elements and other repeats has never been assessed. Results The investigation of BORIS and CTCF binding to DNA repeats in the K562 cancer cells dependent on BORIS for self-renewal by ChIP-chip and ChIP-seq revealed three classes of occupancy by these proteins: elements cohabited by BORIS and CTCF, CTCF-only bound, or BORIS-only bound. The CTCF-only enrichment is characteristic for evolutionary old and inactive repeat classes, while BORIS and CTCF co-binding predominately occurs at uncharacterized tandem repeats. These repeats form staggered cluster binding sites, which are a prerequisite for CTCF and BORIS co-binding. At the same time, BORIS preferentially occupies a specific subset of the evolutionary young, transcribed, and mobile genomic repeat family, SVA. Unlike CTCF, BORIS prominently binds to the VNTR region of the SVA repeats in vivo. This suggests a role of BORIS in SVA expression regulation. RNA-seq analysis indicates that BORIS largely serves as a repressor of SVA expression, alongside DNA and histone methylation, with the exception of promoter capture by SVA. Conclusions Thus, BORIS directly binds to, and regulates SVA repeats, which are essentially movable CpG islands, via clusters of BORIS binding sites. This finding uncovers a new function of the global germline-specific transcriptional regulator BORIS in regulating and repressing the newest class of transposable elements that are actively transposed in human genome when activated. This function of BORIS in cancer cells is likely a reflection of its roles in the germline. Electronic supplementary material The online version of this article (doi:10.1186/s13072-016-0084-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Evgeny Teplyakov
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Qiongfang Wu
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Jingjing Li
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Cheng Chen
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Chengcheng Meng
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Jian Liu
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Susan Robinson
- Laboratory of Immunogenetics, NIH, NIAID, Rockville, MD 20852 USA
| | - Dmitry Loukinov
- Laboratory of Immunogenetics, NIH, NIAID, Rockville, MD 20852 USA
| | - Abdelhalim Boukaba
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Andrew Paul Hutchins
- Department of Biology, Southern University of Science and Technology of China, Shenzhen, 518055 Guangdong China
| | | | - Alexander Strunnikov
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
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228
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Uusküla-Reimand L, Hou H, Samavarchi-Tehrani P, Rudan MV, Liang M, Medina-Rivera A, Mohammed H, Schmidt D, Schwalie P, Young EJ, Reimand J, Hadjur S, Gingras AC, Wilson MD. Topoisomerase II beta interacts with cohesin and CTCF at topological domain borders. Genome Biol 2016; 17:182. [PMID: 27582050 PMCID: PMC5006368 DOI: 10.1186/s13059-016-1043-8] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 08/10/2016] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Type II DNA topoisomerases (TOP2) regulate DNA topology by generating transient double stranded breaks during replication and transcription. Topoisomerase II beta (TOP2B) facilitates rapid gene expression and functions at the later stages of development and differentiation. To gain new insight into the genome biology of TOP2B, we used proteomics (BioID), chromatin immunoprecipitation, and high-throughput chromosome conformation capture (Hi-C) to identify novel proximal TOP2B protein interactions and characterize the genomic landscape of TOP2B binding at base pair resolution. RESULTS Our human TOP2B proximal protein interaction network included members of the cohesin complex and nucleolar proteins associated with rDNA biology. TOP2B associates with DNase I hypersensitivity sites, allele-specific transcription factor (TF) binding, and evolutionarily conserved TF binding sites on the mouse genome. Approximately half of all CTCF/cohesion-bound regions coincided with TOP2B binding. Base pair resolution ChIP-exo mapping of TOP2B, CTCF, and cohesin sites revealed a striking structural ordering of these proteins along the genome relative to the CTCF motif. These ordered TOP2B-CTCF-cohesin sites flank the boundaries of topologically associating domains (TADs) with TOP2B positioned externally and cohesin internally to the domain loop. CONCLUSIONS TOP2B is positioned to solve topological problems at diverse cis-regulatory elements and its occupancy is a highly ordered and prevalent feature of CTCF/cohesin binding sites that flank TADs.
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Affiliation(s)
- Liis Uusküla-Reimand
- Genetics and Genome Biology Program, SickKids Research Institute, Toronto, ON Canada
- Department of Gene Technology, Tallinn University of Technology, Tallinn, Estonia
| | - Huayun Hou
- Genetics and Genome Biology Program, SickKids Research Institute, Toronto, ON Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON Canada
| | | | - Matteo Vietri Rudan
- Research Department of Cancer Biology, Cancer Institute, University College London, London, UK
| | - Minggao Liang
- Genetics and Genome Biology Program, SickKids Research Institute, Toronto, ON Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON Canada
| | - Alejandra Medina-Rivera
- Genetics and Genome Biology Program, SickKids Research Institute, Toronto, ON Canada
- Present address: International Laboratory for Research in Human Genomics, Universidad Nacional Autónoma de México, Juriquilla, Querétaro Mexico
| | - Hisham Mohammed
- Cancer Research UK, Cambridge Institute, University of Cambridge, Cambridge, UK
- Present address: The Babraham Institute, Cambridge, UK
| | - Dominic Schmidt
- Cancer Research UK, Cambridge Institute, University of Cambridge, Cambridge, UK
- Present address: Syncona Partners LLP, London, UK
| | - Petra Schwalie
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, UK
- Present address: Laboratory of Systems Biology and Genetics, Lausanne, Switzerland
| | - Edwin J. Young
- Genetics and Genome Biology Program, SickKids Research Institute, Toronto, ON Canada
| | - Jüri Reimand
- Ontario Institute for Cancer Research, Toronto, ON Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON Canada
| | - Suzana Hadjur
- Research Department of Cancer Biology, Cancer Institute, University College London, London, UK
| | - Anne-Claude Gingras
- Department of Molecular Genetics, University of Toronto, Toronto, ON Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON Canada
| | - Michael D. Wilson
- Genetics and Genome Biology Program, SickKids Research Institute, Toronto, ON Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON Canada
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229
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Abstract
Retrotransposons have generated about 40 % of the human genome. This review examines the strategies the cell has evolved to coexist with these genomic "parasites", focussing on the non-long terminal repeat retrotransposons of humans and mice. Some of the restriction factors for retrotransposition, including the APOBECs, MOV10, RNASEL, SAMHD1, TREX1, and ZAP, also limit replication of retroviruses, including HIV, and are part of the intrinsic immune system of the cell. Many of these proteins act in the cytoplasm to degrade retroelement RNA or inhibit its translation. Some factors act in the nucleus and involve DNA repair enzymes or epigenetic processes of DNA methylation and histone modification. RISC and piRNA pathway proteins protect the germline. Retrotransposon control is relaxed in some cell types, such as neurons in the brain, stem cells, and in certain types of disease and cancer, with implications for human health and disease. This review also considers potential pitfalls in interpreting retrotransposon-related data, as well as issues to consider for future research.
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Affiliation(s)
- John L. Goodier
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA 212051
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230
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Ecco G, Cassano M, Kauzlaric A, Duc J, Coluccio A, Offner S, Imbeault M, Rowe HM, Turelli P, Trono D. Transposable Elements and Their KRAB-ZFP Controllers Regulate Gene Expression in Adult Tissues. Dev Cell 2016; 36:611-23. [PMID: 27003935 DOI: 10.1016/j.devcel.2016.02.024] [Citation(s) in RCA: 147] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 02/10/2016] [Accepted: 02/24/2016] [Indexed: 12/21/2022]
Abstract
KRAB-containing zinc finger proteins (KRAB-ZFPs) are early embryonic controllers of transposable elements (TEs), which they repress with their cofactor KAP1 through histone and DNA methylation, a process thought to result in irreversible silencing. Using a target-centered functional screen, we matched murine TEs with their cognate KRAB-ZFP. We found the paralogs ZFP932 and Gm15446 to bind overlapping but distinguishable subsets of ERVK (endogenous retrovirus K), repress these elements in embryonic stem cells, and regulate secondarily the expression of neighboring genes. Most importantly, we uncovered that these KRAB-ZFPs and KAP1 control TEs in adult tissues, in cell culture and in vivo, where they partner up to modulate cellular genes. Therefore, TEs and KRAB-ZFPs establish transcriptional networks that likely regulate not only development but also many physiological events. Given the high degree of species specificity of TEs and KRAB-ZFPs, these results have important implications for understanding the biology of higher vertebrates, including humans.
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Affiliation(s)
- Gabriela Ecco
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Station 19, 1015 Lausanne, Switzerland
| | - Marco Cassano
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Station 19, 1015 Lausanne, Switzerland
| | - Annamaria Kauzlaric
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Station 19, 1015 Lausanne, Switzerland
| | - Julien Duc
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Station 19, 1015 Lausanne, Switzerland
| | - Andrea Coluccio
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Station 19, 1015 Lausanne, Switzerland
| | - Sandra Offner
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Station 19, 1015 Lausanne, Switzerland
| | - Michaël Imbeault
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Station 19, 1015 Lausanne, Switzerland
| | - Helen M Rowe
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Station 19, 1015 Lausanne, Switzerland
| | - Priscilla Turelli
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Station 19, 1015 Lausanne, Switzerland
| | - Didier Trono
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Station 19, 1015 Lausanne, Switzerland.
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231
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Insights into the Evolution of a Snake Venom Multi-Gene Family from the Genomic Organization of Echis ocellatus SVMP Genes. Toxins (Basel) 2016; 8:toxins8070216. [PMID: 27420095 PMCID: PMC4963849 DOI: 10.3390/toxins8070216] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 06/29/2016] [Accepted: 07/06/2016] [Indexed: 02/04/2023] Open
Abstract
The molecular events underlying the evolution of the Snake Venom Metalloproteinase (SVMP) family from an A Disintegrin And Metalloproteinase (ADAM) ancestor remain poorly understood. Comparative genomics may provide decisive information to reconstruct the evolutionary history of this multi-locus toxin family. Here, we report the genomic organization of Echis ocellatus genes encoding SVMPs from the PII and PI classes. Comparisons between them and between these genes and the genomic structures of Anolis carolinensis ADAM28 and E. ocellatus PIII-SVMP EOC00089 suggest that insertions and deletions of intronic regions played key roles along the evolutionary pathway that shaped the current diversity within the multi-locus SVMP gene family. In particular, our data suggest that emergence of EOC00028-like PI-SVMP from an ancestral PII(e/d)-type SVMP involved splicing site mutations that abolished both the 3′ splice AG acceptor site of intron 12* and the 5′ splice GT donor site of intron 13*, and resulted in the intronization of exon 13* and the consequent destruction of the structural integrity of the PII-SVMP characteristic disintegrin domain.
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232
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Göke J, Ng HH. CTRL+INSERT: retrotransposons and their contribution to regulation and innovation of the transcriptome. EMBO Rep 2016; 17:1131-44. [PMID: 27402545 DOI: 10.15252/embr.201642743] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 06/20/2016] [Indexed: 12/25/2022] Open
Abstract
The human genome contains millions of fragments from retrotransposons-highly repetitive DNA sequences that were once able to "copy and paste" themselves to other regions in the genome. However, the majority of retrotransposons have lost this capacity through acquisition of mutations or through endogenous silencing mechanisms. Without this imminent threat of transposition, retrotransposons have the potential to act as a major source of genomic innovation. Indeed, large numbers of retrotransposons have been found to be active in specific contexts: as gene regulatory elements and promoters for protein-coding genes or long noncoding RNAs, among others. In this review, we summarise recent findings about retrotransposons, with implications in gene expression regulation, the expansion of gene isoform diversity and the generation of long noncoding RNAs. We highlight key examples that demonstrate their role in cellular identity and their versatility as markers of cell states, and we discuss how their dysregulation may contribute to the formation of and possibly therapeutic response in human cancers.
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Affiliation(s)
- Jonathan Göke
- Computational and Systems Biology, Genome Institute of Singapore, Singapore
| | - Huck Hui Ng
- Gene Regulation Laboratory, Genome Institute of Singapore, Singapore Department of Biochemistry, National University of Singapore, Singapore Department of Biological Sciences, National University of Singapore, Singapore School of Biological Sciences, Nanyang Technological University, Singapore
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233
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Du J, Leung A, Trac C, Lee M, Parks BW, Lusis AJ, Natarajan R, Schones DE. Chromatin variation associated with liver metabolism is mediated by transposable elements. Epigenetics Chromatin 2016; 9:28. [PMID: 27398095 PMCID: PMC4939004 DOI: 10.1186/s13072-016-0078-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 06/29/2016] [Indexed: 01/23/2023] Open
Abstract
Background Functional regulatory regions in eukaryotic genomes are characterized by the disruption of nucleosomes leading to accessible chromatin. The modulation of chromatin accessibility is one of the key mediators of transcriptional regulation, and variation in chromatin accessibility across individuals has been linked to complex traits and disease susceptibility. While mechanisms responsible for chromatin variation across individuals have been investigated, the overwhelming majority of chromatin variation remains unexplained. Furthermore, the processes through which the variation of chromatin accessibility contributes to phenotypic diversity remain poorly understood. Results We profiled chromatin accessibility in liver from seven strains of mice with phenotypic diversity in response to a high-fat/high-sucrose (HF/HS) diet and identified reproducible chromatin variation across the individuals. We found that sites of variable chromatin accessibility were more likely to coincide with particular classes of transposable elements (TEs) than sites with common chromatin signatures. Evolutionarily younger long interspersed nuclear elements (LINEs) are particularly likely to harbor variable chromatin sites. These younger LINEs are enriched for binding sites of immune-associated transcription factors, whereas older LINEs are enriched for liver-specific transcription factors. Genomic region enrichment analysis indicates that variable chromatin sites at TEs may function to regulate liver metabolic pathways. CRISPR-Cas9 deletion of a number of variable chromatin sites at TEs altered expression of nearby metabolic genes. Finally, we show that polymorphism of TEs and differential DNA methylation at TEs can both influence chromatin variation. Conclusions Our results demonstrate that specific classes of TEs show variable chromatin accessibility across strains of mice that display phenotypic diversity in response to a HF/HS diet. These results indicate that chromatin variation at TEs is an important contributor to phenotypic variation among populations. Electronic supplementary material The online version of this article (doi:10.1186/s13072-016-0078-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Juan Du
- Department of Diabetes Complications and Metabolism, Beckman Research Institute, City of Hope, Duarte, CA USA ; Irell & Manella Graduate School of Biological Sciences, City of Hope, Duarte, CA USA
| | - Amy Leung
- Department of Diabetes Complications and Metabolism, Beckman Research Institute, City of Hope, Duarte, CA USA
| | - Candi Trac
- Department of Diabetes Complications and Metabolism, Beckman Research Institute, City of Hope, Duarte, CA USA
| | - Michael Lee
- Department of Diabetes Complications and Metabolism, Beckman Research Institute, City of Hope, Duarte, CA USA ; Irell & Manella Graduate School of Biological Sciences, City of Hope, Duarte, CA USA
| | - Brian W Parks
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI USA
| | - Aldons J Lusis
- Department of Medicine, University of California, Los Angeles, CA USA
| | - Rama Natarajan
- Department of Diabetes Complications and Metabolism, Beckman Research Institute, City of Hope, Duarte, CA USA ; Irell & Manella Graduate School of Biological Sciences, City of Hope, Duarte, CA USA
| | - Dustin E Schones
- Department of Diabetes Complications and Metabolism, Beckman Research Institute, City of Hope, Duarte, CA USA ; Irell & Manella Graduate School of Biological Sciences, City of Hope, Duarte, CA USA
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234
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Placental Hypomethylation Is More Pronounced in Genomic Loci Devoid of Retroelements. G3-GENES GENOMES GENETICS 2016; 6:1911-21. [PMID: 27172225 PMCID: PMC4938645 DOI: 10.1534/g3.116.030379] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The human placenta is hypomethylated compared to somatic tissues. However, the degree and specificity of placental hypomethylation across the genome is unclear. We assessed genome-wide methylation of the human placenta and compared it to that of the neutrophil, a representative homogeneous somatic cell. We observed global hypomethylation in placenta (relative reduction of 22%) compared to neutrophils. Placental hypomethylation was pronounced in intergenic regions and gene bodies, while the unmethylated state of the promoter remained conserved in both tissues. For every class of repeat elements, the placenta showed lower methylation but the degree of hypomethylation differed substantially between these classes. However, some retroelements, especially the evolutionarily younger Alu elements, retained high levels of placental methylation. Surprisingly, nonretrotransposon-containing sequences showed a greater degree of placental hypomethylation than retrotransposons in every genomic element (intergenic, introns, and exons) except promoters. The differentially methylated fragments (DMFs) in placenta and neutrophils were enriched in gene-poor and CpG-poor regions. The placentally hypomethylated DMFs were enriched in genomic regions that are usually inactive, whereas hypermethylated DMFs were enriched in active regions. Hypomethylation of the human placenta is not specific to retroelements, indicating that the evolutionary advantages of placental hypomethylation go beyond those provided by expression of retrotransposons and retrogenes.
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235
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Evolutionary direction of processed pseudogenes. SCIENCE CHINA-LIFE SCIENCES 2016; 59:839-49. [PMID: 27333782 DOI: 10.1007/s11427-016-5074-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/08/2016] [Indexed: 10/21/2022]
Abstract
While some pseudogenes have been reported to play important roles in gene regulation, little is known about the possible relationship between pseudogene functions and evolutionary process of pseudogenes, or about the forces responsible for the pseudogene evolution. In this study, we characterized human processed pseudogenes in terms of evolutionary dynamics. Our results show that pseudogenes tend to evolve toward: lower GC content, strong dinucleotide bias, reduced abundance of transcription factor binding motifs and short palindromes, and decreased ability to form nucleosomes. We explored possible evolutionary forces that shaped the evolution pattern of pseudogenes, and concluded that mutations in pseudogenes are likely determined, at least partially, by neighbor-dependent mutational bias and recombination-associated selection.
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236
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Thompson PJ, Macfarlan TS, Lorincz MC. Long Terminal Repeats: From Parasitic Elements to Building Blocks of the Transcriptional Regulatory Repertoire. Mol Cell 2016; 62:766-76. [PMID: 27259207 PMCID: PMC4910160 DOI: 10.1016/j.molcel.2016.03.029] [Citation(s) in RCA: 172] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The life cycle of endogenous retroviruses (ERVs), also called long terminal repeat (LTR) retrotransposons, begins with transcription by RNA polymerase II followed by reverse transcription and re-integration into the host genome. While most ERVs are relics of ancient integration events, "young" proviruses competent for retrotransposition-found in many mammals, but not humans-represent an ongoing threat to host fitness. As a consequence, several restriction pathways have evolved to suppress their activity at both transcriptional and post-transcriptional stages of the viral life cycle. Nevertheless, accumulating evidence has revealed that LTR sequences derived from distantly related ERVs have been exapted as regulatory sequences for many host genes in a wide range of cell types throughout mammalian evolution. Here, we focus on emerging themes from recent studies cataloging the diversity of ERV LTRs acting as important transcriptional regulatory elements in mammals and explore the molecular features that likely account for LTR exaptation in developmental and tissue-specific gene regulation.
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Affiliation(s)
- Peter J Thompson
- Department of Medical Genetics, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Todd S Macfarlan
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA.
| | - Matthew C Lorincz
- Department of Medical Genetics, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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237
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Hall LL, Lawrence JB. RNA as a fundamental component of interphase chromosomes: could repeats prove key? Curr Opin Genet Dev 2016; 37:137-147. [PMID: 27218204 DOI: 10.1016/j.gde.2016.04.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 04/01/2016] [Accepted: 04/06/2016] [Indexed: 11/29/2022]
Abstract
Beginning with the precedent of XIST RNA as a 'chromosomal RNA' (cRNA), there is growing interest in the possibility that a diversity of non-coding RNAs may function in chromatin. We review findings which lead us to suggest that RNA is essentially a widespread component of interphase chromosomes. Further, RNA likely contributes to architecture and regulation, with repeat-rich 'junk' RNA in euchromatin (ecRNA) promoting a more open chromatin state. Thousands of low-abundance nuclear RNAs have been reported, however it remains a challenge to determine which of these may function in chromatin. Recent findings indicate that repetitive sequences are enriched in chromosome-associated non-coding RNAs, and repeat-rich RNA shows unusual properties, including localization and stability, with similarities to XIST RNA. We suggest two frontiers in genome biology are emerging and may intersect: the broad contribution of RNA to interphase chromosomes and the distinctive properties of repeat-rich intronic or intergenic junk sequences that may play a role in chromosome structure and regulation.
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Affiliation(s)
- Lisa L Hall
- Department of Cell & Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA
| | - Jeanne B Lawrence
- Department of Cell & Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA.
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238
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Mulero-Navarro S, Fernandez-Salguero PM. New Trends in Aryl Hydrocarbon Receptor Biology. Front Cell Dev Biol 2016; 4:45. [PMID: 27243009 PMCID: PMC4863130 DOI: 10.3389/fcell.2016.00045] [Citation(s) in RCA: 180] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 04/28/2016] [Indexed: 12/28/2022] Open
Abstract
Traditionally considered as a critical intermediate in the toxic and carcinogenic response to dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD), the Aryl hydrocarbon/Dioxin receptor (AhR) has proven to be also an important regulator of cell physiology and organ homeostasis. AhR has become an interesting and actual area of research mainly boosted by a significant number of recent studies analyzing its contribution to the proper functioning of the immune, hepatic, cardiovascular, vascular and reproductive systems. At the cellular level, AhR establishes functional interactions with signaling pathways governing cell proliferation and cell cycle, cell morphology, cell adhesion and cell migration. Two exciting new aspects in AhR biology deal with its implication in the control of cell differentiation and its more than likely involvement in cell pluripotency and stemness. In fact, it is possible that AhR could help modulate the balance between differentiation and pluripotency in normal and transformed tumor cells. At the molecular level, AhR regulates an increasingly large array of physiologically relevant genes either by traditional transcription-dependent mechanisms or by unforeseen processes involving genomic insulators, chromatin dynamics and the transcription of mobile genetic elements. AhR is also closely related to epigenetics, not only from the point of view of target gene expression but also with respect to its own regulation by promoter methylation. It is reasonable to consider that deregulation of these many functions could have a causative role, or at least contribute to, human disease. Consequently, several laboratories have proposed that AhR could be a valuable tool as diagnostic marker and/or therapeutic target in human pathologies. An additional point of interest is the possibility of regulating AhR activity by endogenous non-toxic low weight molecules agonist or antagonist molecules that could be present or included in the diet. In this review, we will address these molecular and functional features of AhR biology within physiological and pathological contexts.
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Affiliation(s)
- Sonia Mulero-Navarro
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura Badajoz, Spain
| | - Pedro M Fernandez-Salguero
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura Badajoz, Spain
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239
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Casanova M, Liyakat Ali TM, Rougeulle C. Enlightening the contribution of the dark matter to the X chromosome inactivation process in mammals. Semin Cell Dev Biol 2016; 56:48-57. [PMID: 27174438 DOI: 10.1016/j.semcdb.2016.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 05/04/2016] [Accepted: 05/04/2016] [Indexed: 02/07/2023]
Abstract
X-chromosome inactivation (XCI) in mammals represents an exceptional example of transcriptional co-regulation occurring at the level of an entire chromosome. XCI is considered as a means to compensate for gene dosage imbalance between sexes, yet the largest part of the chromosome is composed of repeated elements of different nature and origins. Here we consider XCI from a repeat point of view, interrogating the mechanisms for inactivating X chromosome-derived repeated sequences and discussing the contribution of repetitive elements to the silencing process itself and to its evolution.
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Affiliation(s)
- Miguel Casanova
- Sorbonne Paris Cité, Epigenetics and Cell Fate, UMR 7216 CNRS, Université Paris Diderot, Paris, France
| | | | - Claire Rougeulle
- Sorbonne Paris Cité, Epigenetics and Cell Fate, UMR 7216 CNRS, Université Paris Diderot, Paris, France.
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240
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Gerdes P, Richardson SR, Mager DL, Faulkner GJ. Transposable elements in the mammalian embryo: pioneers surviving through stealth and service. Genome Biol 2016; 17:100. [PMID: 27161170 PMCID: PMC4862087 DOI: 10.1186/s13059-016-0965-5] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Transposable elements (TEs) are notable drivers of genetic innovation. Over evolutionary time, TE insertions can supply new promoter, enhancer, and insulator elements to protein-coding genes and establish novel, species-specific gene regulatory networks. Conversely, ongoing TE-driven insertional mutagenesis, nonhomologous recombination, and other potentially deleterious processes can cause sporadic disease by disrupting genome integrity or inducing abrupt gene expression changes. Here, we discuss recent evidence suggesting that TEs may contribute regulatory innovation to mammalian embryonic and pluripotent states as a means to ward off complete repression by their host genome.
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Affiliation(s)
- Patricia Gerdes
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Sandra R Richardson
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Dixie L Mager
- Department of Medical Genetics, Terry Fox Laboratory, British Columbia Cancer Agency, University of British Columbia, Vancouver, BC, V5Z 1L3, Canada.
| | - Geoffrey J Faulkner
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia. .,School of Biomedical Sciences, University of Queensland, Brisbane, QLD 4072, Australia.
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241
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Genome-Wide Analysis of Transposon and Retroviral Insertions Reveals Preferential Integrations in Regions of DNA Flexibility. G3-GENES GENOMES GENETICS 2016; 6:805-17. [PMID: 26818075 PMCID: PMC4825651 DOI: 10.1534/g3.115.026849] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
DNA transposons and retroviruses are important transgenic tools for genome engineering. An important consideration affecting the choice of transgenic vector is their insertion site preferences. Previous large-scale analyses of Ds transposon integration sites in plants were done on the basis of reporter gene expression or germ-line transmission, making it difficult to discern vertebrate integration preferences. Here, we compare over 1300 Ds transposon integration sites in zebrafish with Tol2 transposon and retroviral integration sites. Genome-wide analysis shows that Ds integration sites in the presence or absence of marker selection are remarkably similar and distributed throughout the genome. No strict motif was found, but a preference for structural features in the target DNA associated with DNA flexibility (Twist, Tilt, Rise, Roll, Shift, and Slide) was observed. Remarkably, this feature is also found in transposon and retroviral integrations in maize and mouse cells. Our findings show that structural features influence the integration of heterologous DNA in genomes, and have implications for targeted genome engineering.
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242
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Bire S, Casteret S, Piégu B, Beauclair L, Moiré N, Arensbuger P, Bigot Y. Mariner Transposons Contain a Silencer: Possible Role of the Polycomb Repressive Complex 2. PLoS Genet 2016; 12:e1005902. [PMID: 26939020 PMCID: PMC4777549 DOI: 10.1371/journal.pgen.1005902] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 02/05/2016] [Indexed: 12/31/2022] Open
Abstract
Transposable elements are driving forces for establishing genetic innovations such as transcriptional regulatory networks in eukaryotic genomes. Here, we describe a silencer situated in the last 300 bp of the Mos1 transposase open reading frame (ORF) which functions in vertebrate and arthropod cells. Functional silencers are also found at similar locations within three other animal mariner elements, i.e. IS630-Tc1-mariner (ITm) DD34D elements, Himar1, Hsmar1 and Mcmar1. These silencers are able to impact eukaryotic promoters monitoring strong, moderate or low expression as well as those of mariner elements located upstream of the transposase ORF. We report that the silencing involves at least two transcription factors (TFs) that are conserved within animal species, NFAT-5 and Alx1. These cooperatively act with YY1 to trigger the silencing activity. Four other housekeeping transcription factors (TFs), neuron restrictive silencer factor (NRSF), GAGA factor (GAF) and GTGT factor (GTF), were also found to have binding sites within mariner silencers but their impact in modulating the silencer activity remains to be further specified. Interestingly, an NRSF binding site was found to overlap a 30 bp motif coding a highly conserved PHxxYSPDLAPxD peptide in mariner transposases. We also present experimental evidence that silencing is mainly achieved by co-opting the host Polycomb Repressive Complex 2 pathway. However, we observe that when PRC2 is impaired another host silencing pathway potentially takes over to maintain weak silencer activity. Mariner silencers harbour features of Polycomb Response Elements, which are probably a way for mariner elements to self-repress their transcription and mobility in somatic and germinal cells when the required TFs are expressed. At the evolutionary scale, mariner elements, through their exaptation, might have been a source of silencers playing a role in the chromatin configuration in eukaryotic genomes. Transposons are mobile DNA sequences that have long co-evolved with the genome of their hosts. Consequently, they are involved in the generation of mutations, as well as the creation of genes and regulatory networks. Controlling the transposon activity, and consequently its negative effects on both the host soma and germ line, is a challenge for the survival of both the host and the transposon. To silence transposons, hosts often use defence mechanisms involving DNA methylation and RNA interference pathways. Here we show that mariner transposons can self-regulate their activity by using a silencer element located in their DNA sequence. The silencer element interferes with host housekeeping protein transcription factors involved in the polycomb silencing pathways. As the regulation of chromatin configuration by polycomb is an important regulator of animal development, our findings open the possibility that mariner silencers might have been exapted during animal evolution to participate in certain regulation pathways of their hosts. Since some of the TFs involved in mariner silencer activity play a role at different stages of nervous system development and neuron differentiation, it might be possible that mariner transposons can be active during some steps of cell differentiation. Interestingly, mariner transposons (i.e. IS630-Tc1-mariner (ITm) DD34D transposons) have so far only been found in genomes of animals having a nervous system.
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Affiliation(s)
- Solenne Bire
- PRC, UMR INRA-CNRS 7247, PRC, Nouzilly, France
- Institute of Biotechnology, University of Lausanne, and Center for Biotechnology UNIL-EPFL, Lausanne, Switzerland
| | | | | | | | | | - Peter Arensbuger
- Biological Sciences Department, California State Polytechnic University, Pomona, California, United States of America
| | - Yves Bigot
- PRC, UMR INRA-CNRS 7247, PRC, Nouzilly, France
- * E-mail:
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243
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Persson J, Steglich B, Smialowska A, Boyd M, Bornholdt J, Andersson R, Schurra C, Arcangioli B, Sandelin A, Nielsen O, Ekwall K. Regulating retrotransposon activity through the use of alternative transcription start sites. EMBO Rep 2016; 17:753-68. [PMID: 26902262 PMCID: PMC5341516 DOI: 10.15252/embr.201541866] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 01/13/2016] [Indexed: 01/22/2023] Open
Abstract
Retrotransposons, the ancestors of retroviruses, have the potential for gene disruption and genomic takeover if not kept in check. Paradoxically, although host cells repress these elements by multiple mechanisms, they are transcribed and are even activated under stress conditions. Here, we describe a new mechanism of retrotransposon regulation through transcription start site (TSS) selection by altered nucleosome occupancy. We show that Fun30 chromatin remodelers cooperate to maintain a high level of nucleosome occupancy at retrotransposon-flanking long terminal repeat (LTR) elements. This enforces the use of a downstream TSS and the production of a truncated RNA incapable of reverse transcription and retrotransposition. However, in stressed cells, nucleosome occupancy at LTR elements is reduced, and the TSS shifts to allow for productive transcription. We propose that controlled retrotransposon transcription from a nonproductive TSS allows for rapid stress-induced activation, while preventing uncontrolled transposon activity in the genome.
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Affiliation(s)
- Jenna Persson
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Babett Steglich
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Agata Smialowska
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Mette Boyd
- Department of Biology, The Bioinformatics Centre, University of Copenhagen, Copenhagen, Denmark Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Jette Bornholdt
- Department of Biology, The Bioinformatics Centre, University of Copenhagen, Copenhagen, Denmark Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Robin Andersson
- Department of Biology, The Bioinformatics Centre, University of Copenhagen, Copenhagen, Denmark
| | - Catherine Schurra
- Unite Dynamique du Génome, Département Génomes et Génétique, Pasteur Institute, Paris, France
| | - Benoit Arcangioli
- Unite Dynamique du Génome, Département Génomes et Génétique, Pasteur Institute, Paris, France
| | - Albin Sandelin
- Department of Biology, The Bioinformatics Centre, University of Copenhagen, Copenhagen, Denmark Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Olaf Nielsen
- Department of Biology, Cell Cycle and Genome Stability Group, University of Copenhagen, Copenhagen, Denmark
| | - Karl Ekwall
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
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244
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Abstract
Differentiating somatic cells are progressively restricted to specialized functions during ontogeny, but they can be experimentally directed to form other cell types, including those with complete embryonic potential. Early nuclear reprogramming methods, such as somatic cell nuclear transfer (SCNT) and cell fusion, posed significant technical hurdles to precise dissection of the regulatory programmes governing cell identity. However, the discovery of reprogramming by ectopic expression of a defined set of transcription factors, known as direct reprogramming, provided a tractable platform to uncover molecular characteristics of cellular specification and differentiation, cell type stability and pluripotency. We discuss the control and maintenance of cellular identity during developmental transitions as they have been studied using direct reprogramming, with an emphasis on transcriptional and epigenetic regulation.
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245
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Morales-Hernández A, González-Rico FJ, Román AC, Rico-Leo E, Alvarez-Barrientos A, Sánchez L, Macia Á, Heras SR, García-Pérez JL, Merino JM, Fernández-Salguero PM. Alu retrotransposons promote differentiation of human carcinoma cells through the aryl hydrocarbon receptor. Nucleic Acids Res 2016; 44:4665-83. [PMID: 26883630 PMCID: PMC4889919 DOI: 10.1093/nar/gkw095] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 02/09/2016] [Indexed: 12/18/2022] Open
Abstract
Cell differentiation is a central process in development and in cancer growth and dissemination. OCT4 (POU5F1) and NANOG are essential for cell stemness and pluripotency; yet, the mechanisms that regulate their expression remain largely unknown. Repetitive elements account for almost half of the Human Genome; still, their role in gene regulation is poorly understood. Here, we show that the dioxin receptor (AHR) leads to differentiation of human carcinoma cells through the transcriptional upregulation of Alu retrotransposons, whose RNA transcripts can repress pluripotency genes. Despite the genome-wide presence of Alu elements, we provide evidences that those located at the NANOG and OCT4 promoters bind AHR, are transcribed by RNA polymerase-III and repress NANOG and OCT4 in differentiated cells. OCT4 and NANOG repression likely involves processing of Alu-derived transcripts through the miRNA machinery involving the Microprocessor and RISC. Consistently, stable AHR knockdown led to basal undifferentiation, impaired Alus transcription and blockade of OCT4 and NANOG repression. We suggest that transcripts produced from AHR-regulated Alu retrotransposons may control the expression of stemness genes OCT4 and NANOG during differentiation of carcinoma cells. The control of discrete Alu elements by specific transcription factors may have a dynamic role in genome regulation under physiological and diseased conditions.
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Affiliation(s)
- Antonio Morales-Hernández
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
| | - Francisco J González-Rico
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
| | - Angel C Román
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avenida Doctor Arce 37, 28002-Madrid, Spain
| | - Eva Rico-Leo
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
| | - Alberto Alvarez-Barrientos
- Servicio de Técnicas Aplicadas a las Biociencias, Universidad de Extremadura, Avenida de Elvas s/n 06071-Badajoz, Spain
| | - Laura Sánchez
- GENYO. Centro de Genómica e Investigación Oncológica: Pfizer/Universidad de Granada/Junta de Andalucía, Avda. de la Ilustración 114, PTS Granada, 18016-Granada, Spain
| | - Ángela Macia
- GENYO. Centro de Genómica e Investigación Oncológica: Pfizer/Universidad de Granada/Junta de Andalucía, Avda. de la Ilustración 114, PTS Granada, 18016-Granada, Spain
| | - Sara R Heras
- GENYO. Centro de Genómica e Investigación Oncológica: Pfizer/Universidad de Granada/Junta de Andalucía, Avda. de la Ilustración 114, PTS Granada, 18016-Granada, Spain
| | - José L García-Pérez
- GENYO. Centro de Genómica e Investigación Oncológica: Pfizer/Universidad de Granada/Junta de Andalucía, Avda. de la Ilustración 114, PTS Granada, 18016-Granada, Spain
| | - Jaime M Merino
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
| | - Pedro M Fernández-Salguero
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
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246
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Gu Z, Jin K, Crabbe MJC, Zhang Y, Liu X, Huang Y, Hua M, Nan P, Zhang Z, Zhong Y. Enrichment analysis of Alu elements with different spatial chromatin proximity in the human genome. Protein Cell 2016; 7:250-266. [PMID: 26861146 PMCID: PMC4818845 DOI: 10.1007/s13238-015-0240-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 11/24/2015] [Indexed: 02/03/2023] Open
Abstract
Transposable elements (TEs) have no longer been totally considered as “junk DNA” for quite a time since the continual discoveries of their multifunctional roles in eukaryote genomes. As one of the most important and abundant TEs that still active in human genome, Alu, a SINE family, has demonstrated its indispensable regulatory functions at sequence level, but its spatial roles are still unclear. Technologies based on 3C (chromosome conformation capture) have revealed the mysterious three-dimensional structure of chromatin, and make it possible to study the distal chromatin interaction in the genome. To find the role TE playing in distal regulation in human genome, we compiled the new released Hi-C data, TE annotation, histone marker annotations, and the genome-wide methylation data to operate correlation analysis, and found that the density of Alu elements showed a strong positive correlation with the level of chromatin interactions (hESC: r = 0.9, P < 2.2 × 1016; IMR90 fibroblasts: r = 0.94, P < 2.2 × 1016) and also have a significant positive correlation with some remote functional DNA elements like enhancers and promoters (Enhancer: hESC: r = 0.997, P = 2.3 × 10−4; IMR90: r = 0.934, P = 2 × 10−2; Promoter: hESC: r = 0.995, P = 3.8 × 10−4; IMR90: r = 0.996, P = 3.2 × 10−4). Further investigation involving GC content and methylation status showed the GC content of Alu covered sequences shared a similar pattern with that of the overall sequence, suggesting that Alu elements also function as the GC nucleotide and CpG site provider. In all, our results suggest that the Alu elements may act as an alternative parameter to evaluate the Hi-C data, which is confirmed by the correlation analysis of Alu elements and histone markers. Moreover, the GC-rich Alu sequence can bring high GC content and methylation flexibility to the regions with more distal chromatin contact, regulating the transcription of tissue-specific genes.
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Affiliation(s)
- Zhuoya Gu
- School of Life Sciences, Fudan University, Shanghai, 200433, China
| | - Ke Jin
- Banting and Best Department of Medical Research, Donnelly Centre, University of Toronto, Toronto, ON, M5S 1A1, Canada
| | - M James C Crabbe
- Department of Zoology, University of Oxford, Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK
- Institute of Biomedical and Environmental Science & Technology, Department of Life Sciences, University of Bedfordshire, Park Square, Luton, LU1 3JU, UK
| | - Yang Zhang
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Champaign, IL, 61801, USA
| | - Xiaolin Liu
- School of Public Health, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Yanyan Huang
- School of Life Sciences, Fudan University, Shanghai, 200433, China
| | - Mengyi Hua
- School of Life Sciences, Fudan University, Shanghai, 200433, China
| | - Peng Nan
- School of Life Sciences, Fudan University, Shanghai, 200433, China.
| | - Zhaolei Zhang
- Banting and Best Department of Medical Research, Donnelly Centre, University of Toronto, Toronto, ON, M5S 1A1, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A1, Canada.
| | - Yang Zhong
- School of Life Sciences, Fudan University, Shanghai, 200433, China.
- Institute of Biodiversity Science and Institute of High Altitude Medicine, Tibet University, Lhasa, 850012, China.
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247
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Molaro A, Malik HS. Hide and seek: how chromatin-based pathways silence retroelements in the mammalian germline. Curr Opin Genet Dev 2016; 37:51-58. [PMID: 26821364 DOI: 10.1016/j.gde.2015.12.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 12/02/2015] [Accepted: 12/14/2015] [Indexed: 01/07/2023]
Abstract
Retroelements comprise a major fraction of most mammalian genomes. To protect their fitness and stability, hosts must keep retroelements in check in their germline. In most tissues mobile element insertions are decorated with chromatin modifications suggestive of transcriptional silencing. However, germline cells undergo massive chromatin reprogramming events, which erase repressive chromatin marks and necessitate de novo re-establishment of silencing. How do host genomes achieve the discrimination necessary for this de novo silencing? A series of recent studies have revealed aspects of the multi-pronged strategy that mammalian genomes use to identify and silence retroelements. These strategies include the use of small RNA-guides, of specialized DNA-binding protein adaptors and of proteins that repair chromatin discontinuities caused by retroelement insertions. Genetic analyses reveal the importance of these mechanisms of protection, each of which specializes in silencing retroelements of different evolutionary ages. Together, these strategies allow mammalian genomes to withstand the high burden of their parasites.
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Affiliation(s)
- Antoine Molaro
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States
| | - Harmit S Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States; Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States.
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248
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Trono D. Transposable Elements, Polydactyl Proteins, and the Genesis of Human-Specific Transcription Networks. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2016; 80:281-8. [PMID: 26763983 DOI: 10.1101/sqb.2015.80.027573] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Transposable elements (TEs) may account for up to two-thirds of the human genome, and as genomic threats they are subjected to epigenetic control mechanisms engaged from the earliest stages of embryonic development. We previously determined that an important component of this process is the sequence-specific recognition of TEs by KRAB (Krüppel-associated box)-containing zinc-finger proteins (KRAB-ZFPs), a large family of tetrapod-restricted transcription factors that act by recruiting inducers of heterochromatin formation and DNA methylation. We further showed that KRAB-ZFPs and their cofactor KAP1 exert a marked influence on the transcription dynamics of embryonic stem cells via their docking of repressor complexes at TE-contained regulatory sequences. It is generally held that, beyond this early embryonic period, TEs become permanently silenced, and that the evolutionary selection of KRAB-ZFPs and other TE controllers is the result of a simple evolutionary arms race between the host and these genetics invaders. Here, I discuss recent evidence that invalidates this dual assumption and instead suggests that KRAB-ZFPs are the instruments of a massive enterprise of TE domestication, whereby transposon-based regulatory sequences and their cellular ligands establish species-specific transcription regulation networks that influence multiple aspects of human development and physiology.
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Affiliation(s)
- Didier Trono
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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249
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Cournac A, Koszul R, Mozziconacci J. The 3D folding of metazoan genomes correlates with the association of similar repetitive elements. Nucleic Acids Res 2016; 44:245-55. [PMID: 26609133 PMCID: PMC4705657 DOI: 10.1093/nar/gkv1292] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 10/13/2015] [Accepted: 11/04/2015] [Indexed: 12/11/2022] Open
Abstract
The potential roles of the numerous repetitive elements found in the genomes of multi-cellular organisms remain speculative. Several studies have suggested a role in stabilizing specific 3D genomic contacts. To test this hypothesis, we exploited inter-chromosomal contacts frequencies obtained from Hi-C experiments and show that the folding of the human, mouse and Drosophila genomes is associated with a significant co-localization of several specific repetitive elements, notably many elements of the SINE family. These repeats tend to be the oldest ones and are enriched in transcription factor binding sites. We propose that the co-localization of these repetitive elements may explain the global conservation of genome folding observed between homologous regions of the human and mouse genome. Taken together, these results support a contribution of specific repetitive elements in maintaining and/or reshaping genome architecture over evolutionary times.
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Affiliation(s)
- Axel Cournac
- LPTMC, Université Pierre et Marie Curie, Sorbonne université, 4 Place Jussieu 75005 Paris, France Institut Pasteur, Group Spatial Regulation of Genomes, Department of Genomes and Genetics, F-75015 Paris, France CNRS, UMR3525, F-75015 Paris, France
| | - Romain Koszul
- Institut Pasteur, Group Spatial Regulation of Genomes, Department of Genomes and Genetics, F-75015 Paris, France CNRS, UMR3525, F-75015 Paris, France
| | - Julien Mozziconacci
- LPTMC, Université Pierre et Marie Curie, Sorbonne université, 4 Place Jussieu 75005 Paris, France
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250
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Lennartsson A, Arner E, Fagiolini M, Saxena A, Andersson R, Takahashi H, Noro Y, Sng J, Sandelin A, Hensch TK, Carninci P. Remodeling of retrotransposon elements during epigenetic induction of adult visual cortical plasticity by HDAC inhibitors. Epigenetics Chromatin 2015; 8:55. [PMID: 26673794 PMCID: PMC4678690 DOI: 10.1186/s13072-015-0043-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/09/2015] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The capacity for plasticity in the adult brain is limited by the anatomical traces laid down during early postnatal life. Removing certain molecular brakes, such as histone deacetylases (HDACs), has proven to be effective in recapitulating juvenile plasticity in the mature visual cortex (V1). We investigated the chromatin structure and transcriptional control by genome-wide sequencing of DNase I hypersensitive sites (DHSS) and cap analysis of gene expression (CAGE) libraries after HDAC inhibition by valproic acid (VPA) in adult V1. RESULTS We found that VPA reliably reactivates the critical period plasticity and induces a dramatic change of chromatin organization in V1 yielding significantly greater accessibility distant from promoters, including at enhancer regions. VPA also induces nucleosome eviction specifically from retrotransposon (in particular SINE) elements. The transiently accessible SINE elements overlap with transcription factor-binding sites of the Fox family. Mapping of transcription start site activity using CAGE revealed transcription of epigenetic and neural plasticity-regulating genes following VPA treatment, which may help to re-program the genomic landscape and reactivate plasticity in the adult cortex. CONCLUSIONS Treatment with HDAC inhibitors increases accessibility to enhancers and repetitive elements underlying brain-specific gene expression and reactivation of visual cortical plasticity.
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Affiliation(s)
- Andreas Lennartsson
- />Department of Biosciences and Nutrition, NOVUM, Karolinska Institutet, Stockholm, Sweden
- />Genome Science Lab, RIKEN, Hirosawa, Wako-shi, Saitama 351-0198 Japan
| | - Erik Arner
- />Division of Genomic Technologies, RIKEN Center for Life Science Technologies, RIKEN Yokohama Institute, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Michela Fagiolini
- />Lab for Neuronal Circuit Development, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198 Japan
- />F. M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115 USA
| | - Alka Saxena
- />Division of Genomic Technologies, RIKEN Center for Life Science Technologies, RIKEN Yokohama Institute, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Robin Andersson
- />Department of Biology and BRIC, The Bioinformatics Centre, University of Copenhagen, Copenhagen, Denmark
| | - Hazuki Takahashi
- />Division of Genomic Technologies, RIKEN Center for Life Science Technologies, RIKEN Yokohama Institute, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Yukihiko Noro
- />Division of Genomic Technologies, RIKEN Center for Life Science Technologies, RIKEN Yokohama Institute, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Judy Sng
- />Lab for Neuronal Circuit Development, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198 Japan
- />F. M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115 USA
- />Department of Pharmacology, National University of Singapore, 10 Medical Drive 05-34, Singapore, Singapore
| | - Albin Sandelin
- />Department of Biology and BRIC, The Bioinformatics Centre, University of Copenhagen, Copenhagen, Denmark
| | - Takao K. Hensch
- />Lab for Neuronal Circuit Development, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198 Japan
- />F. M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115 USA
- />Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, 52 Oxford Street, Cambridge, MA 02138 USA
| | - Piero Carninci
- />Division of Genomic Technologies, RIKEN Center for Life Science Technologies, RIKEN Yokohama Institute, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
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