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Gupta P, Goswami SG, Kumari G, Saravanakumar V, Bhargava N, Rai AB, Singh P, Bhoyar RC, Arvinden VR, Gunda P, Jain S, Narayana VK, Deolankar SC, Prasad TSK, Natarajan VT, Scaria V, Singh S, Ramalingam S. Development of pathophysiologically relevant models of sickle cell disease and β-thalassemia for therapeutic studies. Nat Commun 2024; 15:1794. [PMID: 38413594 PMCID: PMC10899644 DOI: 10.1038/s41467-024-46036-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 02/12/2024] [Indexed: 02/29/2024] Open
Abstract
Ex vivo cellular system that accurately replicates sickle cell disease and β-thalassemia characteristics is a highly sought-after goal in the field of erythroid biology. In this study, we present the generation of erythroid progenitor lines with sickle cell disease and β-thalassemia mutation using CRISPR/Cas9. The disease cellular models exhibit similar differentiation profiles, globin expression and proteome dynamics as patient-derived hematopoietic stem/progenitor cells. Additionally, these cellular models recapitulate pathological conditions associated with both the diseases. Hydroxyurea and pomalidomide treatment enhanced fetal hemoglobin levels. Notably, we introduce a therapeutic strategy for the above diseases by recapitulating the HPFH3 genotype, which reactivates fetal hemoglobin levels and rescues the disease phenotypes, thus making these lines a valuable platform for studying and developing new therapeutic strategies. Altogether, we demonstrate our disease cellular systems are physiologically relevant and could prove to be indispensable tools for disease modeling, drug screenings and cell and gene therapy-based applications.
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Affiliation(s)
- Pragya Gupta
- CSIR- Institute for Genomics and Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Sangam Giri Goswami
- CSIR- Institute for Genomics and Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Geeta Kumari
- Special Center for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Vinodh Saravanakumar
- CSIR- Institute for Genomics and Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, India
| | - Nupur Bhargava
- CSIR- Institute for Genomics and Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, India
| | - Akhila Balakrishna Rai
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to Be University), Mangalore, 575018, India
| | - Praveen Singh
- CSIR- Institute for Genomics and Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Rahul C Bhoyar
- CSIR- Institute for Genomics and Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, India
| | - V R Arvinden
- CSIR- Institute for Genomics and Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Padma Gunda
- Thalassemia and Sickle Cell Society- Kamala Hospital and Research Centre, Shivarampally, Hyderabad, India
| | - Suman Jain
- Thalassemia and Sickle Cell Society- Kamala Hospital and Research Centre, Shivarampally, Hyderabad, India
| | - Vanya Kadla Narayana
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to Be University), Mangalore, 575018, India
| | - Sayali C Deolankar
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to Be University), Mangalore, 575018, India
| | - T S Keshava Prasad
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to Be University), Mangalore, 575018, India
| | - Vivek T Natarajan
- CSIR- Institute for Genomics and Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Vinod Scaria
- CSIR- Institute for Genomics and Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Shailja Singh
- Special Center for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India.
| | - Sivaprakash Ramalingam
- CSIR- Institute for Genomics and Integrative Biology, Mathura Road, Sukhdev Vihar, New Delhi, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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Athanasopoulou K, Chondrou V, Xiropotamos P, Psarias G, Vasilopoulos Y, Georgakilas GK, Sgourou A. Transcriptional repression of lncRNA and miRNA subsets mediated by LRF during erythropoiesis. J Mol Med (Berl) 2023; 101:1097-1112. [PMID: 37486375 PMCID: PMC10482784 DOI: 10.1007/s00109-023-02352-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 07/10/2023] [Accepted: 07/12/2023] [Indexed: 07/25/2023]
Abstract
Non-coding RNA (ncRNA) species, mainly long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been currently imputed for lesser or greater involvement in human erythropoiesis. These RNA subsets operate within a complex circuit with other epigenetic components and transcription factors (TF) affecting chromatin remodeling during cell differentiation. Lymphoma/leukemia-related (LRF) TF exerts higher occupancy on DNA CpG rich sites and is implicated in several differentiation cell pathways and erythropoiesis among them and also directs the epigenetic regulation of hemoglobin transversion from fetal (HbF) to adult (HbA) form by intervening in the γ-globin gene repression. We intended to investigate LRF activity in the evolving landscape of cells' commitment to the erythroid lineage and specifically during HbF to HbA transversion, to qualify this TF as potential repressor of lncRNAs and miRNAs. Transgenic human erythroleukemia cells, overexpressing LRF and further induced to erythropoiesis, were subjected to expression analysis in high LRF occupancy genetic loci-producing lncRNAs. LRF abundance in genetic loci transcribing for studied lncRNAs was determined by ChIP-Seq data analysis. qPCRs were performed to examine lncRNA expression status. Differentially expressed miRNA pre- and post-erythropoiesis induction were assessed by next-generation sequencing (NGS), and their promoter regions were charted. Expression levels of lncRNAs were correlated with DNA methylation status of flanked CpG islands, and contingent co-regulation of hosted miRNAs was considered. LRF-binding sites were overrepresented in LRF overexpressing cell clones during erythropoiesis induction and exerted a significant suppressive effect towards lncRNAs and miRNA collections. Based on present data interpretation, LRF's multiplied binding capacity across genome is suggested to be transient and associated with higher levels of DNA methylation. KEY MESSAGES: During erythropoiesis, LRF displays extensive occupancy across genetic loci. LRF significantly represses subsets of lncRNAs and miRNAs during erythropoiesis. Promoter region CpG islands' methylation levels affect lncRNA expression. MiRNAs embedded within lncRNA loci show differential regulation of expression.
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Affiliation(s)
- Katerina Athanasopoulou
- Biology Laboratory, School of Science and Technology, Hellenic Open University, 26335 Patras, Greece
| | - Vasiliki Chondrou
- Biology Laboratory, School of Science and Technology, Hellenic Open University, 26335 Patras, Greece
| | - Panagiotis Xiropotamos
- Laboratory of Genetics, Section of Genetics, Cell Biology and Development, Department of Biology, University of Patras, 26504 Patras, Greece
| | - Georgios Psarias
- Biology Laboratory, School of Science and Technology, Hellenic Open University, 26335 Patras, Greece
| | - Yiannis Vasilopoulos
- Laboratory of Genetics, Section of Genetics, Cell Biology and Development, Department of Biology, University of Patras, 26504 Patras, Greece
| | - Georgios K. Georgakilas
- Laboratory of Genetics, Section of Genetics, Cell Biology and Development, Department of Biology, University of Patras, 26504 Patras, Greece
- Laboratory of Hygiene and Epidemiology, Faculty of Medicine, University of Thessaly, 41222 Larisa, Greece
| | - Argyro Sgourou
- Biology Laboratory, School of Science and Technology, Hellenic Open University, 26335 Patras, Greece
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3
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Higashi M, Ikehara T, Nakagawa T, Yoneda M, Hattori N, Ikeda M, Ito T. Long noncoding RNAs transcribed downstream of the human β-globin locus regulate β-globin gene expression. J Biochem 2021; 171:287-294. [PMID: 34878533 DOI: 10.1093/jb/mvab130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 11/07/2021] [Indexed: 01/29/2023] Open
Abstract
The five β-like globin genes (ε, Gγ, Aγ, δ, and β) at the human β-globin gene locus are known to be expressed at specific developmental stages, although details of the underlying mechanism remain to be uncovered. Here we used an in vitro transcription assay to clarify the mechanisms that control this gene expression. We first tested nuclear RNA from HeLa cells using RT-qPCR and discovered a long noncoding RNAs (lncRNAs) within a 5.2-kb region beginning 4.4 kb downstream of the β-globin gene coding region. We investigated nuclear RNA from K562 cells using a primer-extension assay and determined the transcription start sites (TSSs) of these lncRNAs. To clarify their functional role, we performed knockdown (KD) of these lncRNAs in K562 cells. Hydroxyurea, which induces differentiation of K562 cells, increased hemoglobin peptide production, and the effect was enhanced by KD of these lncRNAs, which also enhanced upregulation of the γ-globin expression induced by hydroxyurea. To confirm these results, we performed an in vitro transcription assay. Noncoding single-stranded RNAs inhibited β-globin expression, which was upregulated by GATA1. Furthermore, lncRNAs interacted with GATA1 without sequence specificity and inhibited its binding to its target DNA response element in vitro. Our results suggest that lncRNAs downstream of the β-globin gene locus are key factors regulating globin gene ex pression.
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Affiliation(s)
- Miki Higashi
- Department of Biochemistry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.,Department of Physiology, Saitama Medical University, Saitama, Japan
| | - Tsuyoshi Ikehara
- Department of Biochemistry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.,Department of Food Science and Technology, National Fisheries University, Yamaguchi, Japan
| | - Takeya Nakagawa
- Department of Biochemistry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Mitsuhiro Yoneda
- Department of Biochemistry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Naoko Hattori
- Department of Biochemistry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Masaaki Ikeda
- Department of Physiology, Saitama Medical University, Saitama, Japan
| | - Takashi Ito
- Department of Biochemistry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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Starlard-Davenport A, Fitzgerald A, Pace BS. Exploring epigenetic and microRNA approaches for γ-globin gene regulation. Exp Biol Med (Maywood) 2021; 246:2347-2357. [PMID: 34292080 DOI: 10.1177/15353702211028195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Therapeutic interventions aimed at inducing fetal hemoglobin and reducing the concentration of sickle hemoglobin is an effective approach to ameliorating acute and chronic complications of sickle cell disease, exemplified by the long-term use of hydroxyurea. However, there remains an unmet need for the development of additional safe and effective drugs for single agent or combination therapy for individuals with β-hemoglobinopathies. Regulation of the γ-globin to β-globin switch is achieved by chromatin remodeling at the HBB locus on chromosome 11 and interactions of major DNA binding proteins, such as KLF1 and BCL11A in the proximal promoters of the globin genes. Experimental evidence also supports a role of epigenetic modifications including DNA methylation, histone acetylation/methylation, and microRNA expression in γ-globin gene silencing during development. In this review, we will critically evaluate the role of epigenetic mechanisms in γ-globin gene regulation and discuss data generated in tissue culture, pre-clinical animal models, and clinical trials to support drug development to date. The question remains whether modulation of epigenetic pathways will produce sufficient efficacy and specificity for fetal hemoglobin induction and to what extent targeting these pathways form the basis of prospects for clinical therapy.
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Affiliation(s)
- Athena Starlard-Davenport
- Department of Genetics, Genomics and Informatics, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Ashley Fitzgerald
- Department of Genetics, Genomics and Informatics, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Betty S Pace
- Department of Pediatrics, Division of Hematology/Oncology, Augusta University, Augusta, GA 30912, USA
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5
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Enhancer RNA: biogenesis, function, and regulation. Essays Biochem 2021; 64:883-894. [PMID: 33034351 DOI: 10.1042/ebc20200014] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/02/2020] [Accepted: 09/23/2020] [Indexed: 12/30/2022]
Abstract
Enhancers are noncoding DNA elements that are present upstream or downstream of a gene to control its spatial and temporal expression. Specific histone modifications, such as monomethylation on histone H3 lysine 4 (H3K4me1) and H3K27ac, have been widely used to assign enhancer regions in mammalian genomes. In recent years, emerging evidence suggests that active enhancers are bidirectionally transcribed to produce enhancer RNAs (eRNAs). This finding not only adds a new reliable feature to define enhancers but also raises a fundamental question of how eRNAs function to activate transcription. Although some believe that eRNAs are merely transcriptional byproducts, many studies have demonstrated that eRNAs execute crucial tasks in regulating chromatin conformation and transcription activation. In this review, we summarize the current understanding of eRNAs from their biogenesis, functions, and regulation to their pathological significance. Additionally, we discuss the challenges and possible mechanisms of eRNAs in regulated transcription.
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6
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Abstract
The determination of the cellular localization of a noncoding RNA (ncRNA) is highly helpful to decipher its function. RNA-FISH is a powerful method to detect specific RNAs in fixed cells. It allows both localization and quantification of RNA molecules within individual cells and tissues. Refined RNA-FISH methods have also been developed to determine RNA transcription and degradation rates. This chapter describes an RNA-FISH protocol that we developed to study the expression and localization of satellite III (SATIII) RNAs. This specific class of ncRNAs is expressed in response to various cellular stresses, including heat shock. The protocol is based on the use of a biotinylated LNA probe subsequently detected by a Streptavidin, Alexa Fluor® 488 conjugate. A protocol allowing efficient coupling of RNA-FISH and protein detection by immunofluorescence is also described as well as the bioinformatics pipeline, Substructure Analyzer, we recently developed to automate fluorescence signal analysis.
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7
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Lidschreiber K, Jung LA, von der Emde H, Dave K, Taipale J, Cramer P, Lidschreiber M. Transcriptionally active enhancers in human cancer cells. Mol Syst Biol 2021; 17:e9873. [PMID: 33502116 PMCID: PMC7838827 DOI: 10.15252/msb.20209873] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/11/2020] [Accepted: 12/16/2020] [Indexed: 12/30/2022] Open
Abstract
The growth of human cancer cells is driven by aberrant enhancer and gene transcription activity. Here, we use transient transcriptome sequencing (TT-seq) to map thousands of transcriptionally active putative enhancers in fourteen human cancer cell lines covering seven types of cancer. These enhancers were associated with cell type-specific gene expression, enriched for genetic variants that predispose to cancer, and included functionally verified enhancers. Enhancer-promoter (E-P) pairing by correlation of transcription activity revealed ~ 40,000 putative E-P pairs, which were depleted for housekeeping genes and enriched for transcription factors, cancer-associated genes, and 3D conformational proximity. The cell type specificity and transcription activity of target genes increased with the number of paired putative enhancers. Our results represent a rich resource for future studies of gene regulation by enhancers and their role in driving cancerous cell growth.
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Affiliation(s)
- Katja Lidschreiber
- Department of Molecular BiologyMax Planck Institute for Biophysical ChemistryGöttingenGermany
- Department of Biosciences and NutritionKarolinska InstitutetNEOHuddingeSweden
| | - Lisa A Jung
- Department of Biosciences and NutritionKarolinska InstitutetNEOHuddingeSweden
- Department of Cell and Molecular BiologyKarolinska InstitutetBiomedicumSolnaSweden
| | - Henrik von der Emde
- Department of Molecular BiologyMax Planck Institute for Biophysical ChemistryGöttingenGermany
| | - Kashyap Dave
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetBiomedicumSolnaSweden
| | - Jussi Taipale
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetBiomedicumSolnaSweden
- Department of BiochemistryUniversity of CambridgeCambridgeUK
- Genome‐Scale Biology ProgramUniversity of HelsinkiHelsinkiFinland
| | - Patrick Cramer
- Department of Molecular BiologyMax Planck Institute for Biophysical ChemistryGöttingenGermany
- Department of Biosciences and NutritionKarolinska InstitutetNEOHuddingeSweden
| | - Michael Lidschreiber
- Department of Molecular BiologyMax Planck Institute for Biophysical ChemistryGöttingenGermany
- Department of Biosciences and NutritionKarolinska InstitutetNEOHuddingeSweden
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8
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Debrand E, Chakalova L, Miles J, Dai YF, Goyenechea B, Dye S, Osborne CS, Horton A, Harju-Baker S, Pink RC, Caley D, Carter DRF, Peterson KR, Fraser P. An intergenic non-coding RNA promoter required for histone modifications in the human β-globin chromatin domain. PLoS One 2019; 14:e0217532. [PMID: 31412036 PMCID: PMC6693763 DOI: 10.1371/journal.pone.0217532] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/22/2019] [Indexed: 12/05/2022] Open
Abstract
Transcriptome analyses show a surprisingly large proportion of the mammalian genome is transcribed; much more than can be accounted for by genes and introns alone. Most of this transcription is non-coding in nature and arises from intergenic regions, often overlapping known protein-coding genes in sense or antisense orientation. The functional relevance of this widespread transcription is unknown. Here we characterize a promoter responsible for initiation of an intergenic transcript located approximately 3.3 kb and 10.7 kb upstream of the adult-specific human β-globin genes. Mutational analyses in β-YAC transgenic mice show that alteration of intergenic promoter activity results in ablation of H3K4 di- and tri-methylation and H3 hyperacetylation extending over a 30 kb region immediately downstream of the initiation site, containing the adult δ- and β-globin genes. This results in dramatically decreased expression of the adult genes through position effect variegation in which the vast majority of definitive erythroid cells harbor inactive adult globin genes. In contrast, expression of the neighboring ε- and γ-globin genes is completely normal in embryonic erythroid cells, indicating a developmentally specific variegation of the adult domain. Our results demonstrate a role for intergenic non-coding RNA transcription in the propagation of histone modifications over chromatin domains and epigenetic control of β-like globin gene transcription during development.
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Affiliation(s)
- Emmanuel Debrand
- Laboratory of Chromatin and Gene Expression, The Babraham Institute, Babraham Research Campus, Cambridge, United Kingdom
| | - Lyubomira Chakalova
- Laboratory of Chromatin and Gene Expression, The Babraham Institute, Babraham Research Campus, Cambridge, United Kingdom
| | - Joanne Miles
- Laboratory of Chromatin and Gene Expression, The Babraham Institute, Babraham Research Campus, Cambridge, United Kingdom
| | - Yan-Feng Dai
- Laboratory of Chromatin and Gene Expression, The Babraham Institute, Babraham Research Campus, Cambridge, United Kingdom
| | - Beatriz Goyenechea
- Laboratory of Chromatin and Gene Expression, The Babraham Institute, Babraham Research Campus, Cambridge, United Kingdom
| | - Sandra Dye
- Laboratory of Chromatin and Gene Expression, The Babraham Institute, Babraham Research Campus, Cambridge, United Kingdom
| | - Cameron S. Osborne
- Laboratory of Chromatin and Gene Expression, The Babraham Institute, Babraham Research Campus, Cambridge, United Kingdom
| | - Alice Horton
- Laboratory of Chromatin and Gene Expression, The Babraham Institute, Babraham Research Campus, Cambridge, United Kingdom
| | - Susanna Harju-Baker
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Ryan C. Pink
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Daniel Caley
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - David R. F. Carter
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Kenneth R. Peterson
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Peter Fraser
- Laboratory of Chromatin and Gene Expression, The Babraham Institute, Babraham Research Campus, Cambridge, United Kingdom
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9
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Surace AEA, Hedrich CM. The Role of Epigenetics in Autoimmune/Inflammatory Disease. Front Immunol 2019; 10:1525. [PMID: 31333659 PMCID: PMC6620790 DOI: 10.3389/fimmu.2019.01525] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/18/2019] [Indexed: 12/21/2022] Open
Abstract
Historically, systemic self-inflammatory conditions were classified as either autoinflammatory and caused by the innate immune system or autoimmune and driven by adaptive immune responses. However, it became clear that reality is much more complex and that autoimmune/inflammatory conditions range along an “inflammatory spectrum” with primarily autoinflammatory vs. autoimmune conditions resembling extremes at either end. Epigenetic modifications influence gene expression and alter cellular functions without modifying the genomic sequence. Methylation of CpG DNA dinucleotides and/or their hydroxymethylation, post-translational modifications to amino termini of histone proteins, and non-coding RNA expression are main epigenetic events. The pathophysiology of autoimmune/inflammatory diseases has been closely linked with disease causing gene mutations (rare) or a combination of genetic susceptibility and epigenetic modifications arising from exposure to the environment (more common). Over recent years, progress has been made in understanding molecular mechanisms involved in systemic inflammation and the contribution of innate and adaptive immune responses. Epigenetic events have been identified as (i) central pathophysiological factors in addition to genetic disease predisposition and (ii) as co-factors determining clinical pictures and outcomes in individuals with monogenic disease. Thus, a complete understanding of epigenetic contributors to autoimmune/inflammatory disease will result in approaches to predict individual disease outcomes and the introduction of effective, target-directed, and tolerable therapies. Here, we summarize recent findings that signify the importance of epigenetic modifications in autoimmune/inflammatory disorders along the inflammatory spectrum choosing three examples: the autoinflammatory bone condition chronic nonbacterial osteomyelitis (CNO), the “mixed pattern” disorder psoriasis, and the autoimmune disease systemic lupus erythematosus (SLE).
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Affiliation(s)
- Anna Elisa Andrea Surace
- Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Christian M Hedrich
- Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom.,Department of Paediatric Rheumatology, Alder Hey Children's NHS Foundation Trust Hospital, Liverpool, United Kingdom.,Pädiatrische Rheumatologie, Klinik und Poliklinik für Kinder- und Jugendmedizin, Universitätsklinikum Carl Gustav Carus, TU Dresden, Dresden, Germany
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10
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Yin W, Song Y, Chang X. Single-cell RNA-Seq analysis identifies a noncoding interleukin 4 ( IL-4) RNA that post-transcriptionally up-regulates IL-4 production in T helper cells. J Biol Chem 2018; 294:290-298. [PMID: 30404921 DOI: 10.1074/jbc.ra118.004111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 11/02/2018] [Indexed: 12/24/2022] Open
Abstract
High-throughput sequencing has revealed a tremendous complexity of cellular transcriptomes, which is partly due to the generation of multiple alternative transcripts from a single gene locus. Because alternative transcripts often have low abundance in bulk cells, the functions of most of these transcripts and their relationship with their canonical counterparts remain unclear. Here we applied single-cell RNA-Seq to analyze the transcriptome complexity of in vitro-differentiated, murine type 2 T helper (Th2) cells. We found that cytokine gene transcripts contribute most of the intercellular heterogeneity, with a group of universal cytokines, including interleukins 1a, 2, 3, and 16, being bimodally expressed. At the single-cell level, use of alternative promoters prevalently generated alternative transcripts. For instance, although undetectable in bulk cells, a noncoding RNA isoform of IL-4 (IL4nc), which was driven by an intronic promoter in the IL-4 locus, was predominantly expressed in a subset of Th2 cells. IL4nc displayed distinct temporal expression patterns compared with the canonical IL-4 mRNA and post-transcriptionally promoted the production of IL-4 protein in Th2 cells. In conclusion, our findings reveal a mechanism whereby minor noncanonical transcripts post-transcriptionally regulate expression of their cognate canonical genes.
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Affiliation(s)
- Weijie Yin
- Chinese Academy of Sciences Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yan Song
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92037
| | - Xing Chang
- Chinese Academy of Sciences Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
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11
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Line-1: Implications in the etiology of cancer, clinical applications, and pharmacologic targets. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2018; 778:51-60. [DOI: 10.1016/j.mrrev.2018.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 09/15/2018] [Accepted: 09/17/2018] [Indexed: 11/21/2022]
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12
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Iarovaia OV, Kovina AP, Petrova NV, Razin SV, Ioudinkova ES, Vassetzky YS, Ulianov SV. Genetic and Epigenetic Mechanisms of β-Globin Gene Switching. BIOCHEMISTRY (MOSCOW) 2018; 83:381-392. [PMID: 29626925 DOI: 10.1134/s0006297918040090] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Vertebrates have multiple forms of hemoglobin that differ in the composition of their polypeptide chains. During ontogenesis, the composition of these subunits changes. Genes encoding different α- and β-polypeptide chains are located in two multigene clusters on different chromosomes. Each cluster contains several genes that are expressed at different stages of ontogenesis. The phenomenon of stage-specific transcription of globin genes is referred to as globin gene switching. Mechanisms of expression switching, stage-specific activation, and repression of transcription of α- and β-globin genes are of interest from both theoretical and practical points of view. Alteration of balanced expression of globin genes, which usually occurs due to damage to adult β-globin genes, leads to development of severe diseases - hemoglobinopathies. In most cases, reactivation of the fetal hemoglobin gene in patients with β-thalassemia and sickle cell disease can reduce negative consequences of irreversible alterations of expression of the β-globin genes. This review focuses on the current state of research on genetic and epigenetic mechanisms underlying stage-specific switching of β-globin genes.
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Affiliation(s)
- O V Iarovaia
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
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13
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Meng H, Bartholomew B. Emerging roles of transcriptional enhancers in chromatin looping and promoter-proximal pausing of RNA polymerase II. J Biol Chem 2017; 293:13786-13794. [PMID: 29187597 DOI: 10.1074/jbc.r117.813485] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Initiation and regulation of transcription by RNA polymerase II (RNAPII) in eukaryotes rely on the transcriptional regulatory elements. Promoters and enhancers share similar architectures and functions, and the prevailing view is that they can initiate bidirectional transcription. We summarize functional roles of enhancer transcription and possible mechanisms in enhancer-promoter communication. We discuss the potential roles of enhancer RNAs (eRNAs) in early elongation and highlight that transcriptional enhancers might modulate the release of paused RNAPII via 3D chromatin looping. Emerging evidence suggests that transcriptional enhancers regulate the promoter-proximal pausing of RNAPII, a key rate-limiting step required for productive elongation.
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Affiliation(s)
- Huan Meng
- From the Department of Epigenetics and Molecular Carcinogenesis, the University of Texas MD Anderson Cancer Center, Smithville, Texas 78957
| | - Blaine Bartholomew
- From the Department of Epigenetics and Molecular Carcinogenesis, the University of Texas MD Anderson Cancer Center, Smithville, Texas 78957
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14
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Abstract
There is growing evidence that transcription and nuclear organization are tightly linked. Yet, whether transcription of thousands of long noncoding RNAs (lncRNAs) could play a role in this packaging process remains elusive. Although some lncRNAs have been found to have clear roles in nuclear architecture (e.g., FIRRE, NEAT1, XIST, and others), the vast majority remain poorly understood. In this Perspective, we highlight how the act of transcription can affect nuclear architecture. We synthesize several recent findings into a proposed model where the transcription of lncRNAs can serve as guide-posts for shaping genome organization. This model is similar to the game "cat's cradle," where the shape of a string is successively changed by opening up new sites for finger placement. Analogously, transcription of lncRNAs could serve as "grip holds" for nuclear proteins to pull the genome into new positions. This model could explain general lncRNA properties such as low abundance and tissue specificity. Overall, we propose a general framework for how the act of lncRNA transcription could play a role in organizing the 3D genome.
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Affiliation(s)
- Marta Melé
- Harvard Stem Cell and Regenerative Biology Department, Harvard University, Cambridge, MA 02138, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, MA 02138, USA
| | - John L Rinn
- Harvard Stem Cell and Regenerative Biology Department, Harvard University, Cambridge, MA 02138, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, MA 02138, USA; Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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15
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Michel M, Demel C, Zacher B, Schwalb B, Krebs S, Blum H, Gagneur J, Cramer P. TT-seq captures enhancer landscapes immediately after T-cell stimulation. Mol Syst Biol 2017; 13:920. [PMID: 28270558 PMCID: PMC5371733 DOI: 10.15252/msb.20167507] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
To monitor transcriptional regulation in human cells, rapid changes in enhancer and promoter activity must be captured with high sensitivity and temporal resolution. Here, we show that the recently established protocol TT-seq ("transient transcriptome sequencing") can monitor rapid changes in transcription from enhancers and promoters during the immediate response of T cells to ionomycin and phorbol 12-myristate 13-acetate (PMA). TT-seq maps eRNAs and mRNAs every 5 min after T-cell stimulation with high sensitivity and identifies many new primary response genes. TT-seq reveals that the synthesis of 1,601 eRNAs and 650 mRNAs changes significantly within only 15 min after stimulation, when standard RNA-seq does not detect differentially expressed genes. Transcription of enhancers that are primed for activation by nucleosome depletion can occur immediately and simultaneously with transcription of target gene promoters. Our results indicate that enhancer transcription is a good proxy for enhancer regulatory activity in target gene activation, and establish TT-seq as a tool for monitoring the dynamics of enhancer landscapes and transcription programs during cellular responses and differentiation.
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Affiliation(s)
- Margaux Michel
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Carina Demel
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Benedikt Zacher
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Björn Schwalb
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Stefan Krebs
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Helmut Blum
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Julien Gagneur
- Department of Informatics, Technische Universität München, Garching, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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16
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Rougemaille M, Libri D. Control of cryptic transcription in eukaryotes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 702:122-31. [PMID: 21713682 DOI: 10.1007/978-1-4419-7841-7_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Over the last few years, the development of large-scale technologies has radically modified our conception of genome-wide transcriptional control by unveiling an unexpected high complexity of the eukaryotic transcriptome. In organisms ranging from yeast to human, a considerable number of novel small RNA species have been discovered in regions that were previously thought to be incompatible with high levels of transcription. Intriguingly, these transcripts, which are rapidly targeted for degradation by the exosome, appear to be devoid of any coding potential and may be the consequence of unwanted transcription events. However, the notion that an important fraction of these RNAs represent by-products of regulatory transcription is progressively emerging. In this chapter, we discuss the recent advances made in our understanding of the shape of the eukaryotic transcriptome. We also focus on the molecular mechanisms that cells exploit to prevent cryptic transcripts from interfering with the expression of protein-coding genes. Finally, we summarize data obtained in different systems suggesting that such RNAs may play a critical role in the regulation of gene expression as well as the evolution of genomes.
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Affiliation(s)
- Mathieu Rougemaille
- LEA Laboratory of Nuclear RNA Metabolism, Centre de Génétique Moléculaire, CNRS-UPR2167, Gif-sur-Yvette, France,
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17
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Li W, Notani D, Rosenfeld MG. Enhancers as non-coding RNA transcription units: recent insights and future perspectives. Nat Rev Genet 2016; 17:207-23. [PMID: 26948815 DOI: 10.1038/nrg.2016.4] [Citation(s) in RCA: 492] [Impact Index Per Article: 61.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Networks of regulatory enhancers dictate distinct cell identities and cellular responses to diverse signals by instructing precise spatiotemporal patterns of gene expression. However, 35 years after their discovery, enhancer functions and mechanisms remain incompletely understood. Intriguingly, recent evidence suggests that many, if not all, functional enhancers are themselves transcription units, generating non-coding enhancer RNAs. This observation provides a fundamental insight into the inter-regulation between enhancers and promoters, which can both act as transcription units; it also raises crucial questions regarding the potential biological roles of the enhancer transcription process and non-coding enhancer RNAs. Here, we review research progress in this field and discuss several important, unresolved questions regarding the roles and mechanisms of enhancers in gene regulation.
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Affiliation(s)
- Wenbo Li
- Howard Hughes Medical Institute, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92037-0648, USA
| | - Dimple Notani
- Howard Hughes Medical Institute, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92037-0648, USA
| | - Michael G Rosenfeld
- Howard Hughes Medical Institute, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92037-0648, USA
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18
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De Kumar B, Krumlauf R. HOXs and lincRNAs: Two sides of the same coin. SCIENCE ADVANCES 2016; 2:e1501402. [PMID: 27034976 PMCID: PMC4805430 DOI: 10.1126/sciadv.1501402] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 11/28/2015] [Indexed: 05/13/2023]
Abstract
The clustered Hox genes play fundamental roles in regulation of axial patterning and elaboration of the basic body plan in animal development. There are common features in the organization and regulatory landscape of Hox clusters associated with their highly conserved functional roles. The presence of transcribed noncoding sequences embedded within the vertebrate Hox clusters is providing insight into a new layer of regulatory information associated with Hox genes.
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Affiliation(s)
- Bony De Kumar
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Robb Krumlauf
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
- Department of Anatomy and Cell Biology, Kansas University Medical Center, Kansas City, KS 66160, USA
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19
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Kim TK, Shiekhattar R. Architectural and Functional Commonalities between Enhancers and Promoters. Cell 2015; 162:948-59. [PMID: 26317464 DOI: 10.1016/j.cell.2015.08.008] [Citation(s) in RCA: 221] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Indexed: 01/23/2023]
Abstract
With the explosion of genome-wide studies of regulated transcription, it has become clear that traditional definitions of enhancers and promoters need to be revisited. These control elements can now be characterized in terms of their local and regional architecture, their regulatory components, including histone modifications and associated binding factors, and their functional contribution to transcription. This Review discusses unifying themes between promoters and enhancers in transcriptional regulatory mechanisms.
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Affiliation(s)
- Tae-Kyung Kim
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA.
| | - Ramin Shiekhattar
- University of Miami Miller School of Medicine, Sylvester Comprehensive Cancer Center, Department of Human Genetics, Biomedical Research Building, Room 719, 1501 NW 10(th) Avenue, Miami, FL 33136, USA.
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20
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Benabdallah NS, Bickmore WA. Regulatory Domains and Their Mechanisms. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2015; 80:45-51. [PMID: 26590168 DOI: 10.1101/sqb.2015.80.027268] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The concept of gene regulation is being refined as our understanding of the role of enhancer elements grows. Although described more than 30 years ago, the mechanisms through which these cis-regulating elements operate remain under debate. With the recognition that most of the human genetic variation contributing to common disease risk lies outside of genes and probably in enhancers, unraveling these mechanisms becomes ever more important. Originally, a popular view was to consider regulatory elements as an entry site for the transcription machinery that could scan the intervening chromatin until the cognate core promoter was located. Now, the most prominent model for distal enhancer-promoter interaction involves direct enhancer/promoter contacts with a looping out of intervening chromatin. However, a rising awareness of the importance of chromatin architecture and organization forces us to consider enhancer-promoter communication in light of the polymer folding properties of chromatin. Here, we discuss how three-dimensional chromatin folding, topological domains, and the constrained motion, plasticity, and accessibility of chromatin could offer a structural basis for regulatory domains that greatly enhances the probability of enhancer-promoter and transcription factor-promoter interactions and gene activation.
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Affiliation(s)
- Nezha S Benabdallah
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH42XU, United Kingdom Edinburgh Super Resolution Imaging Consortium, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH42XU, United Kingdom
| | - Wendy A Bickmore
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH42XU, United Kingdom
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21
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Patrushev LI, Kovalenko TF. Functions of noncoding sequences in mammalian genomes. BIOCHEMISTRY (MOSCOW) 2015; 79:1442-69. [PMID: 25749159 DOI: 10.1134/s0006297914130021] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Most of the mammalian genome consists of nucleotide sequences not coding for proteins. Exons of genes make up only 3% of the human genome, while the significance of most other sequences remains unknown. Recent genome studies with high-throughput methods demonstrate that the so-called noncoding part of the genome may perform important functions. This hypothesis is supported by three groups of experimental data: 1) approximately 10% of the sequences, most of which are located in noncoding parts of the genome, is evolutionarily conserved and thus can be of functional importance; 2) up to 99% of the mammalian genome is being transcribed forming short and long noncoding RNAs in addition to common mRNA; and 3) mutations in noncoding parts of the genome can be accompanied by progression of pathological states of the organism. In the light of these data, in the review we consider the functional role of numerous known sequences of noncoding parts of the genome including introns, DNA methylation regions, enhancers and locus control regions, insulators, S/MAR sequences, pseudogenes, and genes of noncoding RNAs, as well as transposons and simple repeats of centromeric and telomeric regions of chromosomes. The assumption is made that the intergenic noncoding sequences without definite/clear functions can be involved in spatial organization of genetic loci in interphase nuclei.
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Affiliation(s)
- L I Patrushev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
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22
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Wiberg RAW, Halligan DL, Ness RW, Necsulea A, Kaessmann H, Keightley PD. Assessing Recent Selection and Functionality at Long Noncoding RNA Loci in the Mouse Genome. Genome Biol Evol 2015; 7:2432-44. [PMID: 26272717 PMCID: PMC4558870 DOI: 10.1093/gbe/evv155] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/03/2015] [Indexed: 12/27/2022] Open
Abstract
Long noncoding RNAs (lncRNAs) are one of the most intensively studied groups of noncoding elements. Debate continues over what proportion of lncRNAs are functional or merely represent transcriptional noise. Although characterization of individual lncRNAs has identified approximately 200 functional loci across the Eukarya, general surveys have found only modest or no evidence of long-term evolutionary conservation. Although this lack of conservation suggests that most lncRNAs are nonfunctional, the possibility remains that some represent recent evolutionary innovations. We examine recent selection pressures acting on lncRNAs in mouse populations. We compare patterns of within-species nucleotide variation at approximately 10,000 lncRNA loci in a cohort of the wild house mouse, Mus musculus castaneus, with between-species nucleotide divergence from the rat (Rattus norvegicus). Loci under selective constraint are expected to show reduced nucleotide diversity and divergence. We find limited evidence of sequence conservation compared with putatively neutrally evolving ancestral repeats (ARs). Comparisons of sequence diversity and divergence between ARs, protein-coding (PC) exons and lncRNAs, and the associated flanking regions, show weak, but significantly lower levels of sequence diversity and divergence at lncRNAs compared with ARs. lncRNAs conserved deep in the vertebrate phylogeny show lower within-species sequence diversity than lncRNAs in general. A set of 74 functionally characterized lncRNAs show levels of diversity and divergence comparable to PC exons, suggesting that these lncRNAs are under substantial selective constraints. Our results suggest that, in mouse populations, most lncRNA loci evolve at rates similar to ARs, whereas older lncRNAs tend to show signals of selection similar to PC genes.
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Affiliation(s)
- R Axel W Wiberg
- Institute of Evolutionary Biology, University of Edinburgh, United Kingdom Present address: Centre for Biological Diversity, School of Biology, University of St. Andrews, United Kingdom
| | - Daniel L Halligan
- Institute of Evolutionary Biology, University of Edinburgh, United Kingdom
| | - Rob W Ness
- Institute of Evolutionary Biology, University of Edinburgh, United Kingdom
| | - Anamaria Necsulea
- School of Life Sciences, Ecole Polytechnique Fédérale Lausanne, Lausanne, Switzerland
| | - Henrik Kaessmann
- Center for Integrative Genomics, University of Lausanne, Switzerland
| | - Peter D Keightley
- Institute of Evolutionary Biology, University of Edinburgh, United Kingdom
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23
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24
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Roberts TC, Morris KV, Wood MJA. The role of long non-coding RNAs in neurodevelopment, brain function and neurological disease. Philos Trans R Soc Lond B Biol Sci 2015; 369:rstb.2013.0507. [PMID: 25135968 DOI: 10.1098/rstb.2013.0507] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Long non-coding RNAs (lncRNAs) are transcripts with low protein-coding potential that represent a large proportion of the transcriptional output of the cell. Many lncRNAs exhibit features indicative of functionality including tissue-restricted expression, localization to distinct subcellular structures, regulated expression and evolutionary conservation. Some lncRNAs have been shown to associate with chromatin-modifying activities and transcription factors, suggesting that a common mode of action may be to guide protein complexes to target genomic loci. However, the functions (if any) of the vast majority of lncRNA transcripts are currently unknown, and the subject of investigation. Here, we consider the putative role(s) of lncRNAs in neurodevelopment and brain function with an emphasis on the epigenetic regulation of gene expression. Associations of lncRNAs with neurodevelopmental/neuropsychiatric disorders, neurodegeneration and brain cancers are also discussed.
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Affiliation(s)
- Thomas C Roberts
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Kevin V Morris
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA School of Biotechnology and Biomedical Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
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25
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Ulianov SV, Gavrilov AA, Razin SV. Nuclear Compartments, Genome Folding, and Enhancer-Promoter Communication. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 315:183-244. [DOI: 10.1016/bs.ircmb.2014.11.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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26
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Abstract
Rapid development in genome-wide transcriptional analyses has led to the discovery of a large number of non-coding transcripts, also called long non-coding RNA (lncRNA). LncRNAs harbor biological activities including regulation of protein-coding gene expression at epigenetic, transcriptional and post-transcriptional levels. They also take a part in various physiological and pathological processes, participating in cell development, immunity, disease processes and oncogenesis. Here I discuss and summarize, current knowledge about lncRNA origin, function and involvement in human disease.
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Affiliation(s)
- Kyriacos Felekkis
- Department of Life and Health Sciences and University of Nicosia Medical School, University of Nicosia, Nicosia, Cyprus
| | - Konstantinos Voskarides
- Department of Biological Sciences, Molecular Medicine Research Center, University of Cyprus, Nicosia, Cyprus
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27
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Vautrot V, Aigueperse C, Branlant C, Behm-Ansmant I. Fluorescence in situ hybridization of small non-coding RNAs. Methods Mol Biol 2015; 1296:73-83. [PMID: 25791592 DOI: 10.1007/978-1-4939-2547-6_8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
RNA FISH is a powerful method to detect specific RNAs in fixed cells. It allows both localization and quantification of RNA molecules within individual cells and tissues. Refined RNA FISH methods have also been developed to determine RNA transcription and degradation rates. This chapter describes an RNA FISH protocol that we developed in order to study the expression and localization of satellite III RNAs. This specific class of non-coding RNAs is expressed in response to various cellular stresses including heat shock. This protocol is based on the use of a biotinylated LNA probe subsequently detected by a streptavidin-Alexa Fluor(®) 488 conjugate. A protocol allowing efficient coupling of RNA FISH and protein detection by immunofluorescence is also described in this chapter.
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Affiliation(s)
- Valentin Vautrot
- CNRS, UMR 7365 IMoPA, Université de Lorraine, 9 avenue de la Forêt de Haye, Vandoeuvre-lès-Nancy, 54506, France
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28
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Tripathi V, Fei J, Ha T, Prasanth KV. RNA fluorescence in situ hybridization in cultured mammalian cells. Methods Mol Biol 2015; 1206:123-36. [PMID: 25240892 DOI: 10.1007/978-1-4939-1369-5_11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
It is now clear that long noncoding RNAs (lncRNAs) regulate a number of aspects of nuclear organization and gene expression. An important tool for the study of the distribution and function of lncRNAs is RNA fluorescence in situ hybridization (RNA-FISH). The protocols presented in this chapter describe this method in detail and also mention a number of critical points that must be considered when performing this technique.
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Affiliation(s)
- Vidisha Tripathi
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Avenue, Urbana, IL, 61801, USA
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29
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Iarovaia OV, Ioudinkova ES, Petrova NV, Dolgushin KV, Kovina AV, Nefedochkina AV, Vassetzky YS, Razin SV. Evolution of α- and β-globin genes and their regulatory systems in light of the hypothesis of domain organization of the genome. BIOCHEMISTRY (MOSCOW) 2014; 79:1141-50. [PMID: 25539999 DOI: 10.1134/s0006297914110017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The α- and β-globin gene domains are a traditional model for study of the domain organization of the eucaryotic genome because these genes encode hemoglobin, a physiologically important protein. The α-globin and β-globin gene domains are organized in completely different ways, while the expression of globin genes is tightly coordinated, which makes it extremely interesting to study the origin of these genes and the evolution of their regulatory systems. In this review, the organization of the α- and β-globin gene domains and their genomic environment in different taxonomic groups are comparatively analyzed. A new hypothesis of possible evolutionary pathways for segregated α- and β-globin gene domains of warm-blooded animals is proposed.
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Affiliation(s)
- O V Iarovaia
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
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30
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31
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Siggens L, Ekwall K. Epigenetics, chromatin and genome organization: recent advances from the ENCODE project. J Intern Med 2014; 276:201-14. [PMID: 24605849 DOI: 10.1111/joim.12231] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The organization of the genome into functional units, such as enhancers and active or repressed promoters, is associated with distinct patterns of DNA and histone modifications. The Encyclopedia of DNA Elements (ENCODE) project has advanced our understanding of the principles of genome, epigenome and chromatin organization, identifying hundreds of thousands of potential regulatory regions and transcription factor binding sites. Part of the ENCODE consortium, GENCODE, has annotated the human genome with novel transcripts including new noncoding RNAs and pseudogenes, highlighting transcriptional complexity. Many disease variants identified in genome-wide association studies are located within putative enhancer regions defined by the ENCODE project. Understanding the principles of chromatin and epigenome organization will help to identify new disease mechanisms, biomarkers and drug targets, particularly as ongoing epigenome mapping projects generate data for primary human cell types that play important roles in disease.
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Affiliation(s)
- L Siggens
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
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32
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Yerushalmi GM, Salmon-Divon M, Yung Y, Maman E, Kedem A, Ophir L, Elemento O, Coticchio G, Dal Canto M, Mignini Renzinu M, Fadini R, Hourvitz A. Characterization of the human cumulus cell transcriptome during final follicular maturation and ovulation. Mol Hum Reprod 2014; 20:719-35. [PMID: 24770949 DOI: 10.1093/molehr/gau031] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Cumulus expansion and oocyte maturation are central processes in ovulation. Knowledge gained from rodent and other mammalian models has revealed some of the molecular pathways associated with these processes. However, the equivalent pathways in humans have not been thoroughly studied and remain unidentified. Compact cumulus cells (CCs) from germinal vesicle cumulus oocyte complexes (COCs) were obtained from patients undergoing in vitro maturation (IVM) procedures. Expanded CCs from metaphase 2 COC were obtained from patients undergoing IVF/ICSI. Global transcriptome profiles of the samples were obtained using state-of-the-art RNA sequencing techniques. We identified 1746 differentially expressed (DE) genes between compact and expanded CCs. Most of these genes were involved in cellular growth and proliferation, cellular movement, cell cycle, cell-to-cell signaling and interaction, extracellular matrix and steroidogenesis. Out of the DE genes, we found 89 long noncoding RNAs, of which 12 are encoded within introns of genes known to be involved in granulosa cell processes. This suggests that unique noncoding RNA transcripts may contribute to the regulation of cumulus expansion and oocyte maturation. Using global transcriptome sequencing, we were able to generate a library of genes regulated during cumulus expansion and oocyte maturation processes. Analysis of these genes allowed us to identify important new genes and noncoding RNAs potentially involved in COC maturation and cumulus expansion. These results may increase our understanding of the process of oocyte maturation and could ultimately improve the efficacy of IVM treatment.
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Affiliation(s)
- G M Yerushalmi
- IVF Unit and Reproduction Lab, Department of Obstetrics and Gynecology, Sheba Medical Center, Tel Hashomer, Affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - M Salmon-Divon
- Department of Molecular Biology, Ariel University, Ariel, Israel
| | - Y Yung
- IVF Unit and Reproduction Lab, Department of Obstetrics and Gynecology, Sheba Medical Center, Tel Hashomer, Affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - E Maman
- IVF Unit and Reproduction Lab, Department of Obstetrics and Gynecology, Sheba Medical Center, Tel Hashomer, Affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - A Kedem
- IVF Unit and Reproduction Lab, Department of Obstetrics and Gynecology, Sheba Medical Center, Tel Hashomer, Affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - L Ophir
- IVF Unit and Reproduction Lab, Department of Obstetrics and Gynecology, Sheba Medical Center, Tel Hashomer, Affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - O Elemento
- Institute for Computational Biomedicine, Weill Cornell Medical College, New York, NY, USA
| | - G Coticchio
- Biogenesi, Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi 24, 20052 Monza, Italy
| | - M Dal Canto
- Biogenesi, Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi 24, 20052 Monza, Italy
| | - M Mignini Renzinu
- Biogenesi, Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi 24, 20052 Monza, Italy
| | - R Fadini
- Biogenesi, Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi 24, 20052 Monza, Italy
| | - A Hourvitz
- IVF Unit and Reproduction Lab, Department of Obstetrics and Gynecology, Sheba Medical Center, Tel Hashomer, Affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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33
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Affiliation(s)
- Daniel Duzdevich
- Department of Biological Sciences, Department of Chemistry, and Department of
Biochemistry and Molecular
Biophysics and the Howard Hughes Medical Institute, Columbia University, 650 West 168th Street, New York, New York 10032, United
States
| | - Sy Redding
- Department of Biological Sciences, Department of Chemistry, and Department of
Biochemistry and Molecular
Biophysics and the Howard Hughes Medical Institute, Columbia University, 650 West 168th Street, New York, New York 10032, United
States
| | - Eric C. Greene
- Department of Biological Sciences, Department of Chemistry, and Department of
Biochemistry and Molecular
Biophysics and the Howard Hughes Medical Institute, Columbia University, 650 West 168th Street, New York, New York 10032, United
States
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Lam MTY, Li W, Rosenfeld MG, Glass CK. Enhancer RNAs and regulated transcriptional programs. Trends Biochem Sci 2014; 39:170-82. [PMID: 24674738 DOI: 10.1016/j.tibs.2014.02.007] [Citation(s) in RCA: 373] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 02/20/2014] [Accepted: 02/20/2014] [Indexed: 01/06/2023]
Abstract
A large portion of the human genome is transcribed into RNAs without known protein-coding functions, far outnumbering coding transcription units. Extensive studies of long noncoding RNAs (lncRNAs) have clearly demonstrated that they can play critical roles in regulating gene expression, development, and diseases, acting both as transcriptional activators and repressors. More recently, enhancers have been found to be broadly transcribed, resulting in the production of enhancer-derived RNAs, or eRNAs. Here, we review emerging evidence suggesting that at least some eRNAs contribute to enhancer function. We discuss these findings with respect to potential mechanisms of action of eRNAs and other ncRNAs in regulated gene expression.
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Affiliation(s)
- Michael T Y Lam
- Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA
| | - Wenbo Li
- Howard Hughes Medical Institute, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA
| | - Michael G Rosenfeld
- Howard Hughes Medical Institute, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA.
| | - Christopher K Glass
- Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA; Howard Hughes Medical Institute, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA.
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Regulation of Gγ-globin gene by ATF2 and its associated proteins through the cAMP-response element. PLoS One 2013; 8:e78253. [PMID: 24223142 PMCID: PMC3819381 DOI: 10.1371/journal.pone.0078253] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/10/2013] [Indexed: 01/12/2023] Open
Abstract
The upstream Gγ-globin cAMP-response element (G-CRE) plays an important role in regulating Gγ-globin expression through binding of ATF2 and its DNA-binding partners defined in this study. ATF2 knockdown resulted in a significant reduction of γ-globin expression accompanied by decreased ATF2 binding to the G-CRE. By contrast, stable ATF2 expression in K562 cells increased γ-globin transcription which was reduced by ATF2 knockdown. Moreover, a similar effect of ATF2 on γ-globin expression was observed in primary erythroid progenitors. To understand the role of ATF2 in γ-globin expression, chromatographically purified G-CRE/ATF2-interacting proteins were subjected to mass spectrometry analysis; major binding partners included CREB1, cJun, Brg1, and histone deacetylases among others. Immunoprecipitation assays demonstrated interaction of these proteins with ATF2 and in vivo GCRE binding in CD34+ cells undergoing erythroid differentiation which was correlated with γ-globin expression during development. These results suggest synergism between developmental stage-specific recruitments of the ATF2 protein complex and expression of γ-globin during erythropoiesis. Microarray studies in K562 cells support ATF2 plays diverse roles in hematopoiesis and chromatin remodeling.
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Roberts TC, Morris KV, Weinberg MS. Perspectives on the mechanism of transcriptional regulation by long non-coding RNAs. Epigenetics 2013; 9:13-20. [PMID: 24149621 DOI: 10.4161/epi.26700] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Long non-coding RNAs (lncRNAs) are increasingly being recognized as epigenetic regulators of gene transcription. The diversity and complexity of lncRNA genes means that they exert their regulatory effects by a variety of mechanisms. Although there is still much to be learned about the mechanism of lncRNA function, general principles are starting to emerge. In particular, the application of high throughput (deep) sequencing methodologies has greatly advanced our understanding of lncRNA gene function. lncRNAs function as adaptors that link specific chromatin loci with chromatin-remodeling complexes and transcription factors. lncRNAs can act in cis or trans to guide epigenetic-modifier complexes to distinct genomic sites, or act as scaffolds which recruit multiple proteins simultaneously, thereby coordinating their activities. In this review we discuss the genomic organization of lncRNAs, the importance of RNA secondary structure to lncRNA functionality, the multitude of ways in which they interact with the genome, and what evolutionary conservation tells us about their function.
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Affiliation(s)
- Thomas C Roberts
- Department of Molecular and Experimental Medicine; The Scripps Research Institute; La Jolla, CA USA; Department of Physiology, Anatomy and Genetics; University of Oxford; Oxford, United Kingdom
| | - Kevin V Morris
- Department of Molecular and Experimental Medicine; The Scripps Research Institute; La Jolla, CA USA; School of Biotechnology and Biomedical Sciences; University of New South Wales; Kensington, NSW Australia
| | - Marc S Weinberg
- Department of Molecular and Experimental Medicine; The Scripps Research Institute; La Jolla, CA USA; Antiviral Gene Therapy Research Unit; Department of Molecular Medicine and Haematology; School of Pathology; University of the Witwatersrand; Johannesburg, South Africa
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Kornienko AE, Guenzl PM, Barlow DP, Pauler FM. Gene regulation by the act of long non-coding RNA transcription. BMC Biol 2013; 11:59. [PMID: 23721193 PMCID: PMC3668284 DOI: 10.1186/1741-7007-11-59] [Citation(s) in RCA: 549] [Impact Index Per Article: 49.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 05/15/2013] [Indexed: 12/20/2022] Open
Abstract
Long non-protein-coding RNAs (lncRNAs) are proposed to be the largest transcript class in the mouse and human transcriptomes. Two important questions are whether all lncRNAs are functional and how they could exert a function. Several lncRNAs have been shown to function through their product, but this is not the only possible mode of action. In this review we focus on a role for the process of lncRNA transcription, independent of the lncRNA product, in regulating protein-coding-gene activity in cis. We discuss examples where lncRNA transcription leads to gene silencing or activation, and describe strategies to determine if the lncRNA product or its transcription causes the regulatory effect.
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Affiliation(s)
- Aleksandra E Kornienko
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, AKH-BT25,3, 1090, Vienna, Austria
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38
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Simonatto M, Barozzi I, Natoli G. Non-coding transcription at cis-regulatory elements: computational and experimental approaches. Methods 2013; 63:66-75. [PMID: 23542771 DOI: 10.1016/j.ymeth.2013.03.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/18/2013] [Accepted: 03/20/2013] [Indexed: 12/17/2022] Open
Abstract
Mammalian genomes are pervasively transcribed, generating mostly RNAs with no coding potential that display different size, structure and interspecies sequence conservation. A prominent contribution to the ncRNA pool comes from the transcription of cis-regulatory elements, namely promoters, enhancers and locus control regions. While this phenomenon has been extensively documented, possible roles of such ncRNAs in gene regulation are still unclear. Addressing this issue will require experimental strategies dealing with the low abundance of enhancer-templated ncRNAs and aimed at specifically dissecting the relative role of transcription per se vs. RNA products. In this review, we first focus on the identification and characterization of cis-regulatory elements, highlighting the differences between emerging classes of ncRNAs associated to specific chromatin signatures. We then discuss current experimental strategies to dissect the function of nc transcription and computational approaches to the analysis and classification of regulatory sequences identified in next-generation sequencing experiments.
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Affiliation(s)
- Marta Simonatto
- Department of Experimental Oncology, European Institute of Oncology (IEO), Via Adamello 16, 20139 Milan, Italy.
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39
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Witham J, Ouboussad L, Lefevre PF. A NF-κB-dependent dual promoter-enhancer initiates the lipopolysaccharide-mediated transcriptional activation of the chicken lysozyme in macrophages. PLoS One 2013; 8:e59389. [PMID: 23533622 PMCID: PMC3606415 DOI: 10.1371/journal.pone.0059389] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 02/14/2013] [Indexed: 02/06/2023] Open
Abstract
The transcriptional activation of the chicken lysozyme gene (cLys) by lipopolysaccharide (LPS) in macrophages is dependent on transcription of a LPS-Inducible Non-Coding RNA (LINoCR) triggering eviction of the CCCTC-binding factor (CTCF) from a negative regulatory element upstream of the lysozyme transcription start site. LINoCR is transcribed from a promoter originally characterized as a hormone response enhancer in the oviduct. Herein, we report the characterization of this cis-regulatory element (CRE). In activated macrophages, a 60 bp region bound by NF-κB, AP1 and C/EBPβ controls this CRE, which is strictly dependent on NF-κB binding for its activity in luciferase assays. Moreover, the serine/threonine kinase IKKα, known to be recruited by NF-κB to NF-κB-dependent genes is found at the CRE and within the transcribing regions of both cLys and LINoCR. Such repartition suggests a simultaneous promoter and enhancer activity of this CRE, initiating cLys transcriptional activation and driving CTCF eviction. This recruitment was transient despite persistence of both cLys transcription and NF-κB binding to the CRE. Finally, comparing cLys with other LPS-inducible genes indicates that IKKα detection within transcribing regions can be correlated with the presence of the elongating form of RNA polymerase II or concentrated in the 3′ end of the gene.
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Affiliation(s)
- James Witham
- Section of Experimental Haematology, Leeds Institute of Molecular Medicine, University of Leeds, Wellcome Trust Brenner Building, St. James’s University Hospital, Leeds, United Kingdom
| | - Lylia Ouboussad
- Section of Experimental Haematology, Leeds Institute of Molecular Medicine, University of Leeds, Wellcome Trust Brenner Building, St. James’s University Hospital, Leeds, United Kingdom
| | - Pascal F. Lefevre
- Section of Experimental Haematology, Leeds Institute of Molecular Medicine, University of Leeds, Wellcome Trust Brenner Building, St. James’s University Hospital, Leeds, United Kingdom
- * E-mail:
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40
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Abstract
Long noncoding RNAs (lncRNAs) have gained widespread attention in recent years as a potentially new and crucial layer of biological regulation. lncRNAs of all kinds have been implicated in a range of developmental processes and diseases, but knowledge of the mechanisms by which they act is still surprisingly limited, and claims that almost the entirety of the mammalian genome is transcribed into functional noncoding transcripts remain controversial. At the same time, a small number of well-studied lncRNAs have given us important clues about the biology of these molecules, and a few key functional and mechanistic themes have begun to emerge, although the robustness of these models and classification schemes remains to be seen. Here, we review the current state of knowledge of the lncRNA field, discussing what is known about the genomic contexts, biological functions, and mechanisms of action of lncRNAs. We also reflect on how the recent interest in lncRNAs is deeply rooted in biology's longstanding concern with the evolution and function of genomes.
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Affiliation(s)
- Johnny T Y Kung
- Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02114, USA
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41
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Upstream distal regulatory elements contact the Lmo2 promoter in mouse erythroid cells. PLoS One 2012; 7:e52880. [PMID: 23285212 PMCID: PMC3528669 DOI: 10.1371/journal.pone.0052880] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 11/22/2012] [Indexed: 01/06/2023] Open
Abstract
The Lim domain only 2 (Lmo2) gene encodes a transcriptional cofactor critical for the development of hematopoietic stem cells. Several distal regulatory elements have been identified upstream of the Lmo2 gene in the human and mouse genomes that are capable of enhancing reporter gene expression in erythroid cells and may be responsible for the high level transcription of Lmo2 in the erythroid lineage. In this study we investigate how these elements regulate transcription of Lmo2 and whether or not they function cooperatively in the endogenous context. Chromosome conformation capture (3C) experiments show that chromatin-chromatin interactions exist between upstream regulatory elements and the Lmo2 promoter in erythroid cells but that these interactions are absent from kidney where Lmo2 is transcribed at twelve fold lower levels. Specifically, long range chromatin-chromatin interactions occur between the Lmo2 proximal promoter and two broad regions, 3–31 and 66–105 kb upstream of Lmo2, which we term the proximal and distal control regions for Lmo2 (pCR and dCR respectively). Each of these regions is bound by several transcription factors suggesting that multiple regulatory elements cooperate in regulating high level transcription of Lmo2 in erythroid cells. Binding of CTCF and cohesin which support chromatin loops at other loci were also found within the dCR and at the Lmo2 proximal promoter. Intergenic transcription occurs throughout the dCR in erythroid cells but not in kidney suggesting a role for these intergenic transcripts in regulating Lmo2, similar to the broad domain of intergenic transcription observed at the human β-globin locus control region. Our data supports a model in which the dCR functions through a chromatin looping mechanism to contact and enhance Lmo2 transcription specifically in erythroid cells. Furthermore, these chromatin loops are supported by the cohesin complex recruited to both CTCF and transcription factor bound regions.
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Bhardwaj U, McCabe ERB. Multiplex-PCR Assay for the Deletions Causing Hereditary Persistence of Fetal Hemoglobin. ACTA ACUST UNITED AC 2012; 9:151-6. [PMID: 16271016 DOI: 10.1007/bf03260083] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Hereditary persistence of fetal hemoglobin (HPFH) is a benign condition caused by the failure of normal switching from the fetal to the adult beta-globin gene, resulting in continuous production of fetal hemoglobin beyond the perinatal period. To date, eight deletions of variable size and position have been reported for HPFH. Southern hybridization and PCR are the most common methods used to detect each deletion. AIM Our aim was to develop a multiplex-PCR assay to detect these deletions in a single tube in order to facilitate rapid and accurate molecular diagnosis. METHODS AND RESULTS This report is the first application of multiplex-gap-PCR to detect all HPFH deletions simultaneously to expedite diagnosis. The deletion breakpoints were precisely identified for each deletion and primers were designed in the unique regions across the breakpoints of HPFH-1 (Black), HPFH-2 (Ghanaian), HPFH-3 (Asian Indian), HPFH-4 (Italian), HPFH-5 (Italian), HPFH-6 (Vietnamese), HPFH-7 (Kenyan), and SEA-HPFH (Southeast Asian). As many as 16 primers were used in a single amplification reaction by adjusting the relative primer concentrations. The multiplex-PCR approach was standardized on known positive control samples. We identified unique deletion-specific products for each deletion. The results were confirmed by sequence analysis. CONCLUSIONS We conclude that our multiplex-gap PCR strategy provides the most rapid and accurate diagnosis for the deletions in the beta-globin gene cluster causing HPFH.
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Affiliation(s)
- Urvashi Bhardwaj
- Department of Pediatrics, David Geffen School of Medicine at University of California, Los Angeles, UCLA, and Mattel Children's Hospital at UCLA, USA
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43
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Razin SV, Ulianov SV, Ioudinkova ES, Gushchanskaya ES, Gavrilov AA, Iarovaia OV. Domains of α- and β-globin genes in the context of the structural-functional organization of the eukaryotic genome. BIOCHEMISTRY (MOSCOW) 2012; 77:1409-1423. [DOI: 10.1134/s0006297912130019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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44
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Mitchell JA, Clay I, Umlauf D, Chen CY, Moir CA, Eskiw CH, Schoenfelder S, Chakalova L, Nagano T, Fraser P. Nuclear RNA sequencing of the mouse erythroid cell transcriptome. PLoS One 2012; 7:e49274. [PMID: 23209567 PMCID: PMC3510205 DOI: 10.1371/journal.pone.0049274] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 10/08/2012] [Indexed: 12/31/2022] Open
Abstract
In addition to protein coding genes a substantial proportion of mammalian genomes are transcribed. However, most transcriptome studies investigate steady-state mRNA levels, ignoring a considerable fraction of the transcribed genome. In addition, steady-state mRNA levels are influenced by both transcriptional and posttranscriptional mechanisms, and thus do not provide a clear picture of transcriptional output. Here, using deep sequencing of nuclear RNAs (nucRNA-Seq) in parallel with chromatin immunoprecipitation sequencing (ChIP-Seq) of active RNA polymerase II, we compared the nuclear transcriptome of mouse anemic spleen erythroid cells with polymerase occupancy on a genome-wide scale. We demonstrate that unspliced transcripts quantified by nucRNA-seq correlate with primary transcript frequencies measured by RNA FISH, but differ from steady-state mRNA levels measured by poly(A)-enriched RNA-seq. Highly expressed protein coding genes showed good correlation between RNAPII occupancy and transcriptional output; however, genome-wide we observed a poor correlation between transcriptional output and RNAPII association. This poor correlation is due to intergenic regions associated with RNAPII which correspond with transcription factor bound regulatory regions and a group of stable, nuclear-retained long non-coding transcripts. In conclusion, sequencing the nuclear transcriptome provides an opportunity to investigate the transcriptional landscape in a given cell type through quantification of unspliced primary transcripts and the identification of nuclear-retained long non-coding RNAs.
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Affiliation(s)
- Jennifer A Mitchell
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada.
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45
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Kulaeva OI, Hsieh FK, Chang HW, Luse DS, Studitsky VM. Mechanism of transcription through a nucleosome by RNA polymerase II. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:76-83. [PMID: 22982194 DOI: 10.1016/j.bbagrm.2012.08.015] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 08/29/2012] [Accepted: 08/30/2012] [Indexed: 12/31/2022]
Abstract
Efficient maintenance of chromatin structure during passage of RNA polymerase II (Pol II) is critical for cell survival and functioning. Moderate-level transcription of eukaryotic genes by Pol II is accompanied by nucleosome survival, extensive exchange of histones H2A/H2B and minimal exchange of histones H3/H4. Complementary in vitro studies have shown that transcription through chromatin by single Pol II complexes is uniquely coupled with nucleosome survival via formation of a small intranucleosomal DNA loop (Ø-loop) containing the transcribing enzyme. In contrast, transient displacement and exchange of all core histones are observed during intense transcription. Indeed, multiple transcribing Pol II complexes can efficiently overcome the high nucleosomal barrier and displace the entire histone octamer in vitro. Thus, various Pol II complexes can remodel chromatin to different extents. The mechanisms of nucleosome survival and displacement during transcription and the role of DNA-histone interactions and various factors during this process are discussed. This article is part of a Special Issue entitled: RNA polymerase II Transcript Elongation.
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Affiliation(s)
- Olga I Kulaeva
- Department of Pharmacology, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
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46
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Abstract
Different cell types within a single organism are generally distinguished by strikingly different patterns of gene expression, which are dynamic throughout development and adult life. Distal enhancer elements are key drivers of spatiotemporal specificity in gene regulation. Often located tens of kilobases from their target promoters and functioning in an orientation-independent manner, the identification of bona fide enhancers has proved a formidable challenge. With the development of ChIP-seq, global cataloging of putative enhancers has become feasible. Here, we review the current understanding of the chromatin landscape at enhancers and how these chromatin features enable robust identification of tissue-specific enhancers.
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Affiliation(s)
- Gabriel E Zentner
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio 44106, USA
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47
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Natoli G, Andrau JC. Noncoding transcription at enhancers: general principles and functional models. Annu Rev Genet 2012; 46:1-19. [PMID: 22905871 DOI: 10.1146/annurev-genet-110711-155459] [Citation(s) in RCA: 288] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Mammalian genomes are extensively transcribed outside the borders of protein-coding genes. Genome-wide studies recently demonstrated that cis-regulatory genomic elements implicated in transcriptional control, such as enhancers and locus-control regions, represent major sites of extragenic noncoding transcription. Enhancer-templated transcripts provide a quantitatively small contribution to the total amount of cellular nonribosomal RNA; nevertheless, the possibility that enhancer transcription and the resulting enhancer RNAs may, in some cases, have functional roles, rather than represent mere transcriptional noise at accessible genomic regions, is supported by an increasing amount of experimental data. In this article we review the current knowledge on enhancer transcription and its functional implications.
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Affiliation(s)
- Gioacchino Natoli
- Department of Experimental Oncology, European Institute of Oncology (IEO), I-20139 Milan, Italy.
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48
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Maston GA, Landt SG, Snyder M, Green MR. Characterization of enhancer function from genome-wide analyses. Annu Rev Genomics Hum Genet 2012; 13:29-57. [PMID: 22703170 DOI: 10.1146/annurev-genom-090711-163723] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
There has been a recent surge in the use of genome-wide methodologies to identify and annotate the transcriptional regulatory elements in the human genome. Here we review some of these methodologies and the conceptual insights about transcription regulation that have been gained from the use of genome-wide studies. It has become clear that the binding of transcription factors is itself a highly regulated process, and binding does not always appear to have functional consequences. Numerous properties have now been associated with regulatory elements that may be useful in their identification. Several aspects of enhancer function have been shown to be more widespread than was previously appreciated, including the highly combinatorial nature of transcription factor binding, the postinitiation regulation of many target genes, and the binding of enhancers at early stages to maintain their competence during development. Going forward, the integration of multiple genome-wide data sets should become a standard approach to elucidate higher-order regulatory interactions.
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Affiliation(s)
- Glenn A Maston
- Howard Hughes Medical Institute and Programs in Gene Function and Expression and Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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49
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Chen CY, Morris Q, Mitchell JA. Enhancer identification in mouse embryonic stem cells using integrative modeling of chromatin and genomic features. BMC Genomics 2012; 13:152. [PMID: 22537144 PMCID: PMC3406964 DOI: 10.1186/1471-2164-13-152] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 04/26/2012] [Indexed: 11/21/2022] Open
Abstract
Background Epigenetic modifications, transcription factor (TF) availability and differences in chromatin folding influence how the genome is interpreted by the transcriptional machinery responsible for gene expression. Enhancers buried in non-coding regions are found to be associated with significant differences in histone marks between different cell types. In contrast, gene promoters show more uniform modifications across cell types. Here we used histone modification and chromatin-associated protein ChIP-Seq data sets in mouse embryonic stem (ES) cells as well as genomic features to identify functional enhancer regions. Using co-bound sites of OCT4, SOX2 and NANOG (co-OSN, validated enhancers) and co-bound sites of MYC and MYCN (limited enhancer activity) as enhancer positive and negative training sets, we performed multinomial logistic regression with LASSO regularization to identify key features. Results Cross validations reveal that a combination of p300, H3K4me1, MED12 and NIPBL features to be top signatures of co-OSN regions. Using a model from 10 signatures, 83% of top 1277 putative 1 kb enhancer regions (probability greater than or equal to 0.8) overlapped with at least one TF peak from 7 mouse ES cell ChIP-Seq data sets. These putative enhancers are associated with increased gene expression of neighbouring genes and significantly enriched in multiple TF bound loci in agreement with combinatorial models of TF binding. Furthermore, we identified several motifs of known TFs significantly enriched in putative enhancer regions compared to random promoter regions and background. Comparison with an active H3K27ac mark in various cell types confirmed cell type-specificity of these enhancers. Conclusions The top enhancer signatures we identified (p300, H3K4me1, MED12 and NIPBL) will allow for the identification of cell type-specific enhancer regions in diverse cell types.
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Affiliation(s)
- Chih-yu Chen
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
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50
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Krivega I, Dean A. Enhancer and promoter interactions-long distance calls. Curr Opin Genet Dev 2012; 22:79-85. [PMID: 22169023 PMCID: PMC3342482 DOI: 10.1016/j.gde.2011.11.001] [Citation(s) in RCA: 159] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 11/09/2011] [Indexed: 12/23/2022]
Abstract
In metazoans, enhancers of gene transcription must often exert their effects over tens of kilobases of DNA. Over the past decade it has become clear that to do this, enhancers come into close proximity with target promoters with the looping away of intervening sequences. In a few cases proteins that are involved in the establishment or maintenance of these loops have been revealed but how the proper gene target is selected remains mysterious. Chromatin insulators had been appreciated as elements that play a role in enhancer fidelity through their enhancer blocking or barrier activity. However, recent work suggests more direct participation of insulators in enhancer-gene interactions. The emerging view begins to incorporate transcription activation by distant enhancers with large scale nuclear architecture and subnuclear movement.
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Affiliation(s)
- Ivan Krivega
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20982
| | - Ann Dean
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20982
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