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Iñiguez-Muñoz S, Llinàs-Arias P, Ensenyat-Mendez M, Bedoya-López AF, Orozco JIJ, Cortés J, Roy A, Forsberg-Nilsson K, DiNome ML, Marzese DM. Hidden secrets of the cancer genome: unlocking the impact of non-coding mutations in gene regulatory elements. Cell Mol Life Sci 2024; 81:274. [PMID: 38902506 DOI: 10.1007/s00018-024-05314-z] [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: 07/06/2023] [Revised: 12/07/2023] [Accepted: 06/06/2024] [Indexed: 06/22/2024]
Abstract
Discoveries in the field of genomics have revealed that non-coding genomic regions are not merely "junk DNA", but rather comprise critical elements involved in gene expression. These gene regulatory elements (GREs) include enhancers, insulators, silencers, and gene promoters. Notably, new evidence shows how mutations within these regions substantially influence gene expression programs, especially in the context of cancer. Advances in high-throughput sequencing technologies have accelerated the identification of somatic and germline single nucleotide mutations in non-coding genomic regions. This review provides an overview of somatic and germline non-coding single nucleotide alterations affecting transcription factor binding sites in GREs, specifically involved in cancer biology. It also summarizes the technologies available for exploring GREs and the challenges associated with studying and characterizing non-coding single nucleotide mutations. Understanding the role of GRE alterations in cancer is essential for improving diagnostic and prognostic capabilities in the precision medicine era, leading to enhanced patient-centered clinical outcomes.
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Affiliation(s)
- Sandra Iñiguez-Muñoz
- Cancer Epigenetics Laboratory at the Cancer Cell Biology Group, Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Pere Llinàs-Arias
- Cancer Epigenetics Laboratory at the Cancer Cell Biology Group, Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Miquel Ensenyat-Mendez
- Cancer Epigenetics Laboratory at the Cancer Cell Biology Group, Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Andrés F Bedoya-López
- Cancer Epigenetics Laboratory at the Cancer Cell Biology Group, Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Javier I J Orozco
- Saint John's Cancer Institute, Providence Saint John's Health Center, Santa Monica, CA, USA
| | - Javier Cortés
- International Breast Cancer Center (IBCC), Pangaea Oncology, Quiron Group, 08017, Barcelona, Spain
- Medica Scientia Innovation Research SL (MEDSIR), 08018, Barcelona, Spain
- Faculty of Biomedical and Health Sciences, Department of Medicine, Universidad Europea de Madrid, 28670, Madrid, Spain
| | - Ananya Roy
- Department of Immunology, Genetics and Pathology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Karin Forsberg-Nilsson
- Department of Immunology, Genetics and Pathology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
- University of Nottingham Biodiscovery Institute, Nottingham, UK
| | - Maggie L DiNome
- Department of Surgery, Duke University School of Medicine, Durham, NC, USA
| | - Diego M Marzese
- Cancer Epigenetics Laboratory at the Cancer Cell Biology Group, Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain.
- Department of Surgery, Duke University School of Medicine, Durham, NC, USA.
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Roy Chowdhury N, Gurevich V, Shamay M. KSHV genome harbors both constitutive and lytically induced enhancers. J Virol 2024; 98:e0017924. [PMID: 38695538 DOI: 10.1128/jvi.00179-24] [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: 01/30/2024] [Accepted: 04/03/2024] [Indexed: 06/14/2024] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) belongs to the gamma-herpesvirus family and is a well-known human oncogenic virus. In infected cells, the viral genome of 165 kbp is circular DNA wrapped in chromatin. The tight control of gene expression is critical for latency, the transition into the lytic phase, and the development of viral-associated malignancies. Distal cis-regulatory elements, such as enhancers and silencers, can regulate gene expression in a position- and orientation-independent manner. Open chromatin is another characteristic feature of enhancers. To systematically search for enhancers, we cloned all the open chromatin regions in the KSHV genome downstream of the luciferase gene and tested their enhancer activity in infected and uninfected cells. A silencer was detected upstream of the latency-associated nuclear antigen promoter. Two constitutive enhancers were identified in the K12p-OriLyt-R and ORF29 Intron regions, where ORF29 Intron is a tissue-specific enhancer. The following promoters: OriLyt-L, PANp, ALTp, and the terminal repeats (TRs) acted as lytically induced enhancers. The expression of the replication and transcription activator (RTA), the master regulator of the lytic cycle, was sufficient to induce the activity of lytic enhancers in uninfected cells. We propose that the TRs that span about 24 kbp region serve as a "viral super-enhancer" that integrates the repressive effect of the latency-associated nuclear antigen (LANA) with the activating effect of RTA. Utilizing CRISPR activation and interference techniques, we determined the connections between these enhancers and their regulated genes. The silencer and enhancers described here provide an additional layer to the complex gene regulation of herpesviruses.IMPORTANCEIn this study, we performed a systematic functional assay to identify cis-regulatory elements within the genome of the oncogenic herpesvirus, Kaposi's sarcoma-associated herpesvirus (KSHV). Similar to other herpesviruses, KSHV presents both latent and lytic phases. Therefore, our assays were performed in uninfected cells, during latent infection, and under lytic conditions. We identified two constitutive enhancers, one of which seems to be a tissue-specific enhancer. In addition, four lytically induced enhancers, which are all responsive to the replication and transcription activator (RTA), were identified. Furthermore, a silencer was identified between the major latency promoter and the lytic gene locus. Utilizing CRISPR activation and interference techniques, we determined the connections between these enhancers and their regulated genes. The terminal repeats, spanning a region of about 24 kbp, seem like a "viral super-enhancer" that integrates the repressive effect of the latency-associated nuclear antigen (LANA) with the activating effect of RTA to regulate latency to lytic transition.
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Affiliation(s)
- Nilabja Roy Chowdhury
- Daniella Lee Casper Laboratory in Viral Oncology, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Vyacheslav Gurevich
- Daniella Lee Casper Laboratory in Viral Oncology, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Meir Shamay
- Daniella Lee Casper Laboratory in Viral Oncology, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
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3
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Edrei Y, Levy R, Kaye D, Marom A, Radlwimmer B, Hellman A. Methylation-directed regulatory networks determine enhancing and silencing of mutation disease driver genes and explain inter-patient expression variation. Genome Biol 2023; 24:264. [PMID: 38012713 PMCID: PMC10683314 DOI: 10.1186/s13059-023-03094-6] [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: 05/23/2022] [Accepted: 10/23/2023] [Indexed: 11/29/2023] Open
Abstract
BACKGROUND Common diseases manifest differentially between patients, but the genetic origin of this variation remains unclear. To explore possible involvement of gene transcriptional-variation, we produce a DNA methylation-oriented, driver-gene-wide dataset of regulatory elements in human glioblastomas and study their effect on inter-patient gene expression variation. RESULTS In 175 of 177 analyzed gene regulatory domains, transcriptional enhancers and silencers are intermixed. Under experimental conditions, DNA methylation induces enhancers to alter their enhancing effects or convert into silencers, while silencers are affected inversely. High-resolution mapping of the association between DNA methylation and gene expression in intact genomes reveals methylation-related regulatory units (average size = 915.1 base-pairs). Upon increased methylation of these units, their target-genes either increased or decreased in expression. Gene-enhancing and silencing units constitute cis-regulatory networks of genes. Mathematical modeling of the networks highlights indicative methylation sites, which signified the effect of key regulatory units, and add up to make the overall transcriptional effect of the network. Methylation variation in these sites effectively describe inter-patient expression variation and, compared with DNA sequence-alterations, appears as a major contributor of gene-expression variation among glioblastoma patients. CONCLUSIONS We describe complex cis-regulatory networks, which determine gene expression by summing the effects of positive and negative transcriptional inputs. In these networks, DNA methylation induces both enhancing and silencing effects, depending on the context. The revealed mechanism sheds light on the regulatory role of DNA methylation, explains inter-individual gene-expression variation, and opens the way for monitoring the driving forces behind deferential courses of cancer and other diseases.
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Affiliation(s)
- Yifat Edrei
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel
| | - Revital Levy
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel
| | - Daniel Kaye
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel
| | - Anat Marom
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel
| | - Bernhard Radlwimmer
- Division of Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Asaf Hellman
- Department of Developmental Biology and Cancer Research, The Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel.
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4
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Pan JH, Du PF. SilenceREIN: seeking silencers on anchors of chromatin loops by deep graph neural networks. Brief Bioinform 2023; 25:bbad494. [PMID: 38168841 PMCID: PMC10782921 DOI: 10.1093/bib/bbad494] [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: 07/30/2023] [Revised: 11/09/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024] Open
Abstract
Silencers are repressive cis-regulatory elements that play crucial roles in transcriptional regulation. Experimental methods for identifying silencers are always costly and time-consuming. Computational methods, which relies on genomic sequence features, have been introduced as alternative approaches. However, silencers do not have significant epigenomic signature. Therefore, we explore a new way to computationally identify silencers, by incorporating chromatin structural information. We propose the SilenceREIN method, which focuses on finding silencers on anchors of chromatin loops. By using graph neural networks, we extracted chromatin structural information from a regulatory element interaction network. SilenceREIN integrated the chromatin structural information with linear genomic signatures to find silencers. The predictive performance of SilenceREIN is comparable or better than other states-of-the-art methods. We performed a genome-wide scanning to systematically find silencers in human genome. Results suggest that silencers are widespread on anchors of chromatin loops. In addition, enrichment analysis of transcription factor binding motif support our prediction results. As far as we can tell, this is the first attempt to incorporate chromatin structural information in finding silencers. All datasets and source codes of SilenceREIN have been deposited in a GitHub repository (https://github.com/JianHPan/SilenceREIN).
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Affiliation(s)
- Jian-Hua Pan
- College of Intelligence and Computing, Tianjin University, Tianjin 300350, China
| | - Pu-Feng Du
- College of Intelligence and Computing, Tianjin University, Tianjin 300350, China
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5
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Cui Y, Cao Q, Li Y, He M, Liu X. Advances in cis-element- and natural variation-mediated transcriptional regulation and applications in gene editing of major crops. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:5441-5457. [PMID: 37402253 DOI: 10.1093/jxb/erad248] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/28/2023] [Indexed: 07/06/2023]
Abstract
Transcriptional regulation is crucial to control of gene expression. Both spatio-temporal expression patterns and expression levels of genes are determined by the interaction between cis-acting elements and trans-acting factors. Numerous studies have focused on the trans-acting factors that mediate transcriptional regulatory networks. However, cis-acting elements, such as enhancers, silencers, transposons, and natural variations in the genome, are also vital for gene expression regulation and could be utilized by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9)-mediated gene editing to improve crop quality and yield. In this review, we discuss current understanding of cis-element-mediated transcriptional regulation in major crops, including rice (Oryza sativa), wheat (Triticum aestivum), and maize (Zea mays), as well as the latest advancements in gene editing techniques and their applications in crops to highlight prospective strategies for crop breeding.
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Affiliation(s)
- Yue Cui
- College of Teacher Education, Molecular and Cellular Postdoctoral Research Station, Hebei Normal University, Shijiazhuang 050024, China
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Research Center of the Basic Discipline Cell Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China
| | - Qiao Cao
- Shijiazhuang Academy of Agricultural and Forestry Sciences, Shijiazhuang, Hebei Province 050041, China
| | - Yongpeng Li
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Research Center of the Basic Discipline Cell Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China
| | - Mingqi He
- Shijiazhuang Academy of Agricultural and Forestry Sciences, Shijiazhuang, Hebei Province 050041, China
| | - Xigang Liu
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Research Center of the Basic Discipline Cell Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China
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6
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Zhang T, Li L, Sun H, Xu D, Wang G. DeepICSH: a complex deep learning framework for identifying cell-specific silencers and their strength from the human genome. Brief Bioinform 2023; 24:bbad316. [PMID: 37643374 DOI: 10.1093/bib/bbad316] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 07/25/2023] [Accepted: 08/11/2023] [Indexed: 08/31/2023] Open
Abstract
Silencers are noncoding DNA sequence fragments located on the genome that suppress gene expression. The variation of silencers in specific cells is closely related to gene expression and cancer development. Computational approaches that exclusively rely on DNA sequence information for silencer identification fail to account for the cell specificity of silencers, resulting in diminished accuracy. Despite the discovery of several transcription factors and epigenetic modifications associated with silencers on the genome, there is still no definitive biological signal or combination thereof to fully characterize silencers, posing challenges in selecting suitable biological signals for their identification. Therefore, we propose a sophisticated deep learning framework called DeepICSH, which is based on multiple biological data sources. Specifically, DeepICSH leverages a deep convolutional neural network to automatically capture biologically relevant signal combinations strongly associated with silencers, originating from a diverse array of biological signals. Furthermore, the utilization of attention mechanisms facilitates the scoring and visualization of these signal combinations, whereas the employment of skip connections facilitates the fusion of multilevel sequence features and signal combinations, thereby empowering the accurate identification of silencers within specific cells. Extensive experiments on HepG2 and K562 cell line data sets demonstrate that DeepICSH outperforms state-of-the-art methods in silencer identification. Notably, we introduce for the first time a deep learning framework based on multi-omics data for classifying strong and weak silencers, achieving favorable performance. In conclusion, DeepICSH shows great promise for advancing the study and analysis of silencers in complex diseases. The source code is available at https://github.com/lyli1013/DeepICSH.
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Affiliation(s)
- Tianjiao Zhang
- College of Computer and Control Engineering, Northeast Forestry University, Harbin 150040, China
| | - Liangyu Li
- College of Computer and Control Engineering, Northeast Forestry University, Harbin 150040, China
| | - Hailong Sun
- College of Computer and Control Engineering, Northeast Forestry University, Harbin 150040, China
| | - Dali Xu
- College of Computer and Control Engineering, Northeast Forestry University, Harbin 150040, China
| | - Guohua Wang
- College of Computer and Control Engineering, Northeast Forestry University, Harbin 150040, China
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7
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Fan K, Pfister E, Weng Z. Toward a comprehensive catalog of regulatory elements. Hum Genet 2023; 142:1091-1111. [PMID: 36935423 DOI: 10.1007/s00439-023-02519-3] [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: 11/06/2022] [Accepted: 01/03/2023] [Indexed: 03/21/2023]
Abstract
Regulatory elements are the genomic regions that interact with transcription factors to control cell-type-specific gene expression in different cellular environments. A precise and complete catalog of functional elements encoded by the human genome is key to understanding mammalian gene regulation. Here, we review the current state of regulatory element annotation. We first provide an overview of assays for characterizing functional elements, including genome, epigenome, transcriptome, three-dimensional chromatin interaction, and functional validation assays. We then discuss computational methods for defining regulatory elements, including peak-calling and other statistical modeling methods. Finally, we introduce several high-quality lists of regulatory element annotations and suggest potential future directions.
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Affiliation(s)
- Kaili Fan
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Chan Medical School, 368 Plantation Street, ASC5-1069, Worcester, MA, 01605, USA
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Edith Pfister
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Chan Medical School, 368 Plantation Street, ASC5-1069, Worcester, MA, 01605, USA
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Chan Medical School, 368 Plantation Street, ASC5-1069, Worcester, MA, 01605, USA.
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8
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Hussain S, Sadouni N, van Essen D, Dao LTM, Ferré Q, Charbonnier G, Torres M, Gallardo F, Lecellier CH, Sexton T, Saccani S, Spicuglia S. Short tandem repeats are important contributors to silencer elements in T cells. Nucleic Acids Res 2023; 51:4845-4866. [PMID: 36929452 PMCID: PMC10250210 DOI: 10.1093/nar/gkad187] [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: 05/09/2022] [Revised: 02/26/2023] [Accepted: 03/15/2023] [Indexed: 03/18/2023] Open
Abstract
The action of cis-regulatory elements with either activation or repression functions underpins the precise regulation of gene expression during normal development and cell differentiation. Gene activation by the combined activities of promoters and distal enhancers has been extensively studied in normal and pathological contexts. In sharp contrast, gene repression by cis-acting silencers, defined as genetic elements that negatively regulate gene transcription in a position-independent fashion, is less well understood. Here, we repurpose the STARR-seq approach as a novel high-throughput reporter strategy to quantitatively assess silencer activity in mammals. We assessed silencer activity from DNase hypersensitive I sites in a mouse T cell line. Identified silencers were associated with either repressive or active chromatin marks and enriched for binding motifs of known transcriptional repressors. CRISPR-mediated genomic deletions validated the repressive function of distinct silencers involved in the repression of non-T cell genes and genes regulated during T cell differentiation. Finally, we unravel an association of silencer activity with short tandem repeats, highlighting the role of repetitive elements in silencer activity. Our results provide a general strategy for genome-wide identification and characterization of silencer elements.
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Affiliation(s)
- Saadat Hussain
- Aix-Marseille University, Inserm, TAGC, UMR1090, Marseille, France
- Equipe Labélisée Ligue Contre le Cancer, Marseille, France
| | - Nori Sadouni
- Aix-Marseille University, Inserm, TAGC, UMR1090, Marseille, France
- Equipe Labélisée Ligue Contre le Cancer, Marseille, France
| | - Dominic van Essen
- Institute for Research on Cancer and Ageing, IRCAN, 06107 Nice, France
| | - Lan T M Dao
- Aix-Marseille University, Inserm, TAGC, UMR1090, Marseille, France
- Equipe Labélisée Ligue Contre le Cancer, Marseille, France
| | - Quentin Ferré
- Aix-Marseille University, Inserm, TAGC, UMR1090, Marseille, France
- Equipe Labélisée Ligue Contre le Cancer, Marseille, France
| | - Guillaume Charbonnier
- Aix-Marseille University, Inserm, TAGC, UMR1090, Marseille, France
- Equipe Labélisée Ligue Contre le Cancer, Marseille, France
| | - Magali Torres
- Aix-Marseille University, Inserm, TAGC, UMR1090, Marseille, France
- Equipe Labélisée Ligue Contre le Cancer, Marseille, France
| | - Frederic Gallardo
- Aix-Marseille University, Inserm, TAGC, UMR1090, Marseille, France
- Equipe Labélisée Ligue Contre le Cancer, Marseille, France
| | - Charles-Henri Lecellier
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
- LIRMM, University of Montpellier, CNRS, Montpellier, France
| | - Tom Sexton
- Institut de Génétique et de Biologie Moléculaire et Cellulaire – IGBMC (CNRS UMR 7104, INSERM U1258, Université de Strasbourg), 67404 Illkirch, France
| | - Simona Saccani
- Institute for Research on Cancer and Ageing, IRCAN, 06107 Nice, France
| | - Salvatore Spicuglia
- Aix-Marseille University, Inserm, TAGC, UMR1090, Marseille, France
- Equipe Labélisée Ligue Contre le Cancer, Marseille, France
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9
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Vermunt MW, Luan J, Zhang Z, Thrasher AJ, Huang A, Saari MS, Khandros E, Beagrie RA, Zhang S, Vemulamada P, Brilleman M, Lee K, Yano JA, Giardine BM, Keller CA, Hardison RC, Blobel GA. Gene silencing dynamics are modulated by transiently active regulatory elements. Mol Cell 2023; 83:715-730.e6. [PMID: 36868189 PMCID: PMC10719944 DOI: 10.1016/j.molcel.2023.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 12/05/2022] [Accepted: 02/03/2023] [Indexed: 03/05/2023]
Abstract
Transcriptional enhancers have been extensively characterized, but cis-regulatory elements involved in acute gene repression have received less attention. Transcription factor GATA1 promotes erythroid differentiation by activating and repressing distinct gene sets. Here, we study the mechanism by which GATA1 silences the proliferative gene Kit during murine erythroid cell maturation and define stages from initial loss of activation to heterochromatinization. We find that GATA1 inactivates a potent upstream enhancer but concomitantly creates a discrete intronic regulatory region marked by H3K27ac, short noncoding RNAs, and de novo chromatin looping. This enhancer-like element forms transiently and serves to delay Kit silencing. The element is ultimately erased via the FOG1/NuRD deacetylase complex, as revealed by the study of a disease-associated GATA1 variant. Hence, regulatory sites can be self-limiting by dynamic co-factor usage. Genome-wide analyses across cell types and species uncover transiently active elements at numerous genes during repression, suggesting that modulation of silencing kinetics is widespread.
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Affiliation(s)
- Marit W Vermunt
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
| | - Jing Luan
- Medical Scientist Training Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Zhe Zhang
- Department of Biomedical and Health Informatics, The Children's Hospital of Pennsylvania, Philadelphia, PA 19104, USA
| | - A Josephine Thrasher
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Anran Huang
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Megan S Saari
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Eugene Khandros
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Robert A Beagrie
- Chromatin and Disease Group, Wellcome Centre for Human Genetics, Oxford OX3 7BN, UK
| | - Shiping Zhang
- Department of Biomedical and Health Informatics, The Children's Hospital of Pennsylvania, Philadelphia, PA 19104, USA
| | - Pranay Vemulamada
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Matilda Brilleman
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Kiwon Lee
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jennifer A Yano
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Belinda M Giardine
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Cheryl A Keller
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Ross C Hardison
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Gerd A Blobel
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
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10
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Ling L, Mühling B, Jaenichen R, Gompel N. Increased chromatin accessibility promotes the evolution of a transcriptional silencer in Drosophila. SCIENCE ADVANCES 2023; 9:eade6529. [PMID: 36800429 PMCID: PMC9937571 DOI: 10.1126/sciadv.ade6529] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
The loss of discrete morphological traits, the most common evolutionary transition, is typically driven by changes in developmental gene expression. Mutations accumulating in regulatory elements of these genes can disrupt DNA binding sites for transcription factors patterning their spatial expression, or delete entire enhancers. Regulatory elements, however, may be silenced through changes in chromatin accessibility or the emergence of repressive elements. Here, we show that increased chromatin accessibility at the gene yellow, combined with the gain of a repressor site, underlies the loss of a wing spot pigmentation pattern in a Drosophila species. The gain of accessibility of this repressive element is regulated by E93, a transcription factor governing the progress of metamorphosis. This convoluted evolutionary scenario contrasts with the parsimonious mutational paths generally envisioned and often documented for morphological losses. It illustrates how evolutionary changes in chromatin accessibility may directly contribute to morphological diversification.
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11
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Mouri K, Dewey HB, Castro R, Berenzy D, Kales S, Tewhey R. Whole-genome functional characterization of RE1 silencers using a modified massively parallel reporter assay. CELL GENOMICS 2023; 3:100234. [PMID: 36777181 PMCID: PMC9903721 DOI: 10.1016/j.xgen.2022.100234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 09/12/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2022]
Abstract
Both upregulation and downregulation by cis-regulatory elements help modulate precise gene expression. However, our understanding of repressive elements is far more limited than activating elements. To address this gap, we characterized RE1, a group of transcriptional silencers bound by REST, at genome-wide scale using a modified massively parallel reporter assay (MPRAduo). MPRAduo empirically defined a minimal binding strength of REST (REST motif-intrinsic value [m-value]), above which cofactors colocalize and silence transcription. We identified 1,500 human variants that alter RE1 silencing and found that their effect sizes are predictable when they overlap with REST-binding sites above the m-value. Additionally, we demonstrate that non-canonical REST-binding motifs exhibit silencer function only if they precisely align half sites with specific spacer lengths. Our results show mechanistic insights into RE1, which allow us to predict its activity and effect of variants on RE1, providing a paradigm for performing genome-wide functional characterization of transcription-factor-binding sites.
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Affiliation(s)
| | | | | | | | - Susan Kales
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Ryan Tewhey
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
- Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
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12
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Pang B, van Weerd JH, Hamoen FL, Snyder MP. Identification of non-coding silencer elements and their regulation of gene expression. Nat Rev Mol Cell Biol 2022; 24:383-395. [DOI: 10.1038/s41580-022-00549-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2022] [Indexed: 11/09/2022]
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13
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Munk M, Villalobo E, Villalobo A, Berchtold MW. Differential expression of the three independent CaM genes coding for an identical protein: Potential relevance of distinct mRNA stability by different codon usage. Cell Calcium 2022; 107:102656. [DOI: 10.1016/j.ceca.2022.102656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/01/2022] [Accepted: 09/25/2022] [Indexed: 11/24/2022]
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14
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Long-Distance Repression by Human Silencers: Chromatin Interactions and Phase Separation in Silencers. Cells 2022; 11:cells11091560. [PMID: 35563864 PMCID: PMC9101175 DOI: 10.3390/cells11091560] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 12/12/2022] Open
Abstract
Three-dimensional genome organization represents an additional layer in the epigenetic regulation of gene expression. Active transcription controlled by enhancers or super-enhancers has been extensively studied. Enhancers or super-enhancers can recruit activators or co-activators to activate target gene expression through long-range chromatin interactions. Chromatin interactions and phase separation play important roles in terms of enhancer or super-enhancer functioning. Silencers are another major type of cis-regulatory element that can mediate gene regulation by turning off or reducing gene expression. However, compared to active transcription, silencer studies are still in their infancy. This review covers the current knowledge of human silencers, especially the roles of chromatin interactions and phase separation in silencers. This review also proposes future directions for human silencer studies.
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15
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Regulation of Sox8 through lncRNA Mrhl-Mediated Chromatin Looping in Mouse Spermatogonia. Mol Cell Biol 2022; 42:e0047521. [PMID: 35412350 DOI: 10.1128/mcb.00475-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sox8 is a developmentally important transcription factor that plays an important role in sex maintenance and fertility of adult mice. In the B-type spermatogonial cells, Sox8 is regulated by the long noncoding RNAs (lncRNA) Mrhl in a p68-dependant manner under the control of the Wnt signaling pathway. The downregulation of Mrhl leads to the meiotic commitment of the spermatogonial cells in a Sox8-dependant manner. While the molecular players involved in the regulation of transcription at the Sox8 promoter have been worked out, our current study points to the involvement of the architectural proteins CTCF and cohesin in mediating a chromatin loop that brings the Sox8 promoter in contact with a silencer element present within the gene body in the presence of lncRNA Mrhl concomitant with transcriptional repression. Further, lncRNA Mrhl interacts with the Sox8 locus through the formation of a DNA:DNA:RNA triplex, which is necessary for the recruitment of PRC2 to the locus. The downregulation of lncRNA Mrhl results in the promoter-silencer loop giving way to a promoter-enhancer loop. This active transcription-associated chromatin loop is mediated by YY1 and brings the promoter in contact with the enhancer present downstream of the gene.
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16
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Liu B, Li G, Yang J, Li X, Wang H, Yang J, Wen H, He F. The mechanism of immune related signal pathway Egr2-FasL-Fas in transcription regulation and methylated modification of Paralichthys olivaceus under acute hypoxia stress. FISH & SHELLFISH IMMUNOLOGY 2022; 123:152-163. [PMID: 35219829 DOI: 10.1016/j.fsi.2022.02.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 02/04/2022] [Accepted: 02/18/2022] [Indexed: 06/14/2023]
Abstract
Apoptosis genes Egr2, Fas and FasL are related to immune responses. However, the mechanism of these genes inducing apoptosis in fish are still not very clear. An acute hypoxia treatment (1.73 ± 0.06 mg/L) for 24 h was carried out on Japanese flounder (Paralichthys olivaceus). The increasingly dense apoptotic signals at 3 h, 6 h, 12 h by TUNEL in skeletal muscle indicated that hypoxia could quickly affect muscle growth and development. Furthermore, we concluded that the Egr2-FasL-Fas signal pathway, which was located at the upstream of apoptotic executor protein caspases, was related to the apoptosis by quantitative real-time PCR, protein concentration detection in ELISA and double gene in situ hybridization methods. The mechanism of the pathway was researched in transcription regulation and epigenetic modification by dual-luciferase reporter assay and bisulfite modified method, respectively. Egr2, as a transcription factor, could up-regulate the expression of FasL gene. And its binding site was mainly between -479 to -1 of FasL gene promoter. The 5th CpG dinucleotides (-514) methylation levels in FasL gene were significantly affected by hypoxia, and they were negatively correlated with its expressions. These suggested that the -514 site may be a very important site to regulate the FasL gene expression. Above results, we concluded that hypoxia activated the immune related signal pathway Egr2-FasL-Fas to induced skeletal muscle apoptosis to affect growth and development of Japanese flounder. The study revealed the mechanism of hypoxia induced apoptosis, which could provide a reference for fish immunity and aquaculture management.
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Affiliation(s)
- Binghua Liu
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China
| | - Guangling Li
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China
| | - Jun Yang
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China
| | - Xiaohui Li
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China
| | - Hao Wang
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China
| | - Jing Yang
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China
| | - Haishen Wen
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China.
| | - Feng He
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao, 266003, PR China.
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17
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Wei X, Xiang Y, Peters DT, Marius C, Sun T, Shan R, Ou J, Lin X, Yue F, Li W, Southerland KW, Diao Y. HiCAR is a robust and sensitive method to analyze open-chromatin-associated genome organization. Mol Cell 2022; 82:1225-1238.e6. [PMID: 35196517 PMCID: PMC8934281 DOI: 10.1016/j.molcel.2022.01.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 11/08/2021] [Accepted: 01/25/2022] [Indexed: 02/06/2023]
Abstract
The long-range interactions of cis-regulatory elements (cREs) play a central role in gene regulation. cREs can be characterized as accessible chromatin sequences. However, it remains technically challenging to comprehensively identify their spatial interactions. Here, we report a new method HiCAR (Hi-C on accessible regulatory DNA), which utilizes Tn5 transposase and chromatin proximity ligation, for the analysis of open-chromatin-anchored interactions with low-input cells. By applying HiCAR in human embryonic stem cells and lymphoblastoid cells, we demonstrate that HiCAR identifies high-resolution chromatin contacts with an efficiency comparable with that of in situ Hi-C over all distance ranges. Interestingly, we found that the "poised" gene promoters exhibit silencer-like function to repress the expression of distal genes via promoter-promoter interactions. Lastly, we applied HiCAR to 30,000 primary human muscle stem cells and demonstrated that HiCAR is capable of analyzing chromatin accessibility and looping using low-input primary cells and clinical samples.
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Affiliation(s)
- Xiaolin Wei
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Duke Regeneration Center, Duke University Medical Center, Durham, NC 27710, USA
| | - Yu Xiang
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Duke Regeneration Center, Duke University Medical Center, Durham, NC 27710, USA
| | - Derek T Peters
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Duke Regeneration Center, Duke University Medical Center, Durham, NC 27710, USA
| | - Choiselle Marius
- The Cell and Molecular Biology Program, Duke University, Durham, NC 27710, USA
| | - Tongyu Sun
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Duke Regeneration Center, Duke University Medical Center, Durham, NC 27710, USA
| | - Ruocheng Shan
- Center for Genetic Medicine Research, Center for Cancer and Immunology Research at Children's National Medical Center, Washington, DC 20010, USA
| | - Jianhong Ou
- Duke Regeneration Center, Duke University Medical Center, Durham, NC 27710, USA
| | - Xin Lin
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Duke Regeneration Center, Duke University Medical Center, Durham, NC 27710, USA
| | - Feng Yue
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Wei Li
- Center for Genetic Medicine Research, Center for Cancer and Immunology Research at Children's National Medical Center, Washington, DC 20010, USA
| | - Kevin W Southerland
- Department of Surgery, Division of Vascular and Endovascular Surgery, Duke University Medical Center, Durham, NC 27710, USA
| | - Yarui Diao
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Duke Regeneration Center, Duke University Medical Center, Durham, NC 27710, USA; Department of Orthopedic Surgery, Duke University Medical Center, Durham, NC 27710, USA.
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18
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Kidaka T, Sugi T, Hayashida K, Suzuki Y, Xuan X, Dubey JP, Yamagishi J. TSS-seq of Toxoplasma gondii sporozoites revealed a novel motif in stage-specific promoters. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2022; 98:105213. [PMID: 35041968 DOI: 10.1016/j.meegid.2022.105213] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 01/06/2022] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Toxoplasma gondii is one of the most common zoonotic protozoan parasites. It has three major infectious stages: rapidly multiplying tachyzoites (Tz), slowly replicating bradyzoites (Bz) and a resting/free-living stage, sporozoites (Sz). The regulatory mechanisms governing stage-specific gene expression are not fully understood. Few transcriptional start sites (TSS) are known for Sz. In this study, we obtained TSS of Sz using an oligo-capping method and RNA-seq analysis. We identified 1,043,503 TSS in the Sz transcriptome. These defined 38,973 TSS clusters, of which, 11,925 were expressed in Sz and 1535 TSS differentially expressed in Sz. Based on these data, we defined promoter regions and novel sporozoite stage-specific motifs using MEME. TGTANNTACA was distributed around -55 to -75 regions from each TSS. Interestingly, the same motif was reported in another apicomplexan, Plasmodium berghei, as a cis-element of female-specific gametocyte genes, implying the presence of common regulatory machinery. Further comparative analysis should better define the distribution and function of these elements in other members of this important parasitic phylum.
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Affiliation(s)
- Taishi Kidaka
- Division of Collaboration and Education, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido 001-0020, Japan
| | - Tatsuki Sugi
- Division of Collaboration and Education, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido 001-0020, Japan
| | - Kyoko Hayashida
- Division of Collaboration and Education, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido 001-0020, Japan; International Collaboration Unit, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido 001-0020, Japan
| | - Yutaka Suzuki
- Department of Medical Genome Sciences, University of Tokyo, Kashiwa, Chiba 277-8562, Japan
| | - Xuenan Xuan
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
| | - Jitender P Dubey
- United States Department of Agriculture, Agricultural Research Service, Animal Parasitic Diseases Laboratory, Beltsville, MD, 20705-2350, USA
| | - Junya Yamagishi
- Division of Collaboration and Education, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido 001-0020, Japan; International Collaboration Unit, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido 001-0020, Japan.
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19
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He N, Wang W, Fang C, Tan Y, Li L, Hou C. Integration of Count Difference and Curve Similarity in Negative Regulatory Element Detection. Front Genet 2022; 13:818344. [PMID: 35251128 PMCID: PMC8896116 DOI: 10.3389/fgene.2022.818344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/20/2022] [Indexed: 12/05/2022] Open
Abstract
Negative regulatory elements (NREs) down-regulate gene expression by inhibiting the activities of promoters or enhancers. The repressing activity of NREs can be measured globally by massively parallel reporter assays (MPRAs). However, most existing algorithms are designed for the statistical detection of positively enriched signals in MPRA datasets. To identify reduced signals in MPRA experiments, we designed a NRE identification program, fast-NR, by integrating the count and graphic features of sequenced reads to detect NREs using datasets generated by experiments of self-transcribing active regulatory region sequencing (STARR-seq). Fast-NR identified hundreds of silencers in human K562 cells that can be validated by independent methods.
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Affiliation(s)
- Na He
- Harbin Institute of Technology, Harbin, China
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- *Correspondence: Chunhui Hou, ; Na He,
| | - Wenjing Wang
- School of Life Science and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Chao Fang
- Cancer Centre, Faculty of Health Sciences, University of Macau, Macao, China
| | - Yongjian Tan
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Li Li
- Department of Bioinformatics, Huazhong Agricultural University, Wuhan, China
- Hubei Key Laboratory of Agricultural Bioinformatics, Huazhong Agricultural University, Wuhan, China
| | - Chunhui Hou
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- *Correspondence: Chunhui Hou, ; Na He,
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20
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Hoffman JA, Trotter KW, Day CR, Ward JM, Inoue K, Rodriguez J, Archer TK. Multimodal regulatory elements within a hormone-specific super enhancer control a heterogeneous transcriptional response. Mol Cell 2022; 82:803-815.e5. [PMID: 35077705 PMCID: PMC8897972 DOI: 10.1016/j.molcel.2021.12.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 11/02/2021] [Accepted: 12/22/2021] [Indexed: 12/16/2022]
Abstract
The hormone-stimulated glucocorticoid receptor (GR) modulates transcription by interacting with thousands of enhancers and GR binding sites (GBSs) throughout the genome. Here, we examined the effects of GR binding on enhancer dynamics and investigated the contributions of individual GBSs to the hormone response. Hormone treatment resulted in genome-wide reorganization of the enhancer landscape in breast cancer cells. Upstream of the DDIT4 oncogene, GR bound to four sites constituting a hormone-dependent super enhancer. Three GBSs were required as hormone-dependent enhancers that differentially promoted histone acetylation, transcription frequency, and burst size. Conversely, the fourth site suppressed transcription and hormone treatment alleviated this suppression. GR binding within the super enhancer promoted a loop-switching mechanism that allowed interaction of the DDIT4 TSS with the active GBSs. The unique functions of each GR binding site contribute to hormone-induced transcriptional heterogeneity and demonstrate the potential for targeted modulation of oncogene expression.
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Affiliation(s)
- Jackson A Hoffman
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, USA 27709
| | - Kevin W Trotter
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, USA 27709
| | - Christopher R Day
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, USA 27709
| | - James M Ward
- Integrative Bioinformatics, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, USA 27709
| | - Kaoru Inoue
- Clinical Research Branch, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, USA 27709
| | - Joseph Rodriguez
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, USA 27709
| | - Trevor K Archer
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC 27709, USA.
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21
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Schmitz RJ, Grotewold E, Stam M. Cis-regulatory sequences in plants: Their importance, discovery, and future challenges. THE PLANT CELL 2022; 34:718-741. [PMID: 34918159 PMCID: PMC8824567 DOI: 10.1093/plcell/koab281] [Citation(s) in RCA: 89] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 10/20/2021] [Indexed: 05/19/2023]
Abstract
The identification and characterization of cis-regulatory DNA sequences and how they function to coordinate responses to developmental and environmental cues is of paramount importance to plant biology. Key to these regulatory processes are cis-regulatory modules (CRMs), which include enhancers and silencers. Despite the extraordinary advances in high-quality sequence assemblies and genome annotations, the identification and understanding of CRMs, and how they regulate gene expression, lag significantly behind. This is especially true for their distinguishing characteristics and activity states. Here, we review the current knowledge on CRMs and breakthrough technologies enabling identification, characterization, and validation of CRMs; we compare the genomic distributions of CRMs with respect to their target genes between different plant species, and discuss the role of transposable elements harboring CRMs in the evolution of gene expression. This is an exciting time to study cis-regulomes in plants; however, significant existing challenges need to be overcome to fully understand and appreciate the role of CRMs in plant biology and in crop improvement.
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Affiliation(s)
- Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, Georgia 30602, USA
| | - Erich Grotewold
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
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22
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Ma L, Yu L, Jiang BC, Wang J, Guo X, Huang Y, Ren J, Sun N, Gao DS, Ding H, Lu J, Zhou H, Zou L, Gao Y, Wang L, Sun K, Ming Y, Meng Z, Tao YX, Yan M. ZNF382 controls mouse neuropathic pain via silencer-based epigenetic inhibition of Cxcl13 in DRG neurons. J Exp Med 2021; 218:e20210920. [PMID: 34762123 PMCID: PMC8590274 DOI: 10.1084/jem.20210920] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 09/06/2021] [Accepted: 10/20/2021] [Indexed: 02/06/2023] Open
Abstract
Nerve injury-induced changes of gene expression in dorsal root ganglion (DRG) are critical for neuropathic pain genesis. However, how these changes occur remains elusive. Here we report the down-regulation of zinc finger protein 382 (ZNF382) in injured DRG neurons after nerve injury. Rescuing this down-regulation attenuates nociceptive hypersensitivity. Conversely, mimicking this down-regulation produces neuropathic pain symptoms, which are alleviated by C-X-C motif chemokine 13 (CXCL13) knockdown or its receptor CXCR5 knockout. Mechanistically, an identified cis-acting silencer at distal upstream of the Cxcl13 promoter suppresses Cxcl13 transcription via binding to ZNF382. Blocking this binding or genetically deleting this silencer abolishes the ZNF382 suppression on Cxcl13 transcription and impairs ZNF382-induced antinociception. Moreover, ZNF382 down-regulation disrupts the repressive epigenetic complex containing histone deacetylase 1 and SET domain bifurcated 1 at the silencer-promoter loop, resulting in Cxcl13 transcriptional activation. Thus, ZNF382 down-regulation is required for neuropathic pain likely through silencer-based epigenetic disinhibition of CXCL13, a key neuropathic pain player, in DRG neurons.
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Affiliation(s)
- Longfei Ma
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Lina Yu
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Bao-Chun Jiang
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Jiangsu, China
| | - Jingkai Wang
- Department of Orthopedics, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Xinying Guo
- Center for Neurodegeneration and Regeneration, Zilkha Neurogenetic Institute and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Yangyuxin Huang
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Jinxuan Ren
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Na Sun
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Dave Schwinn Gao
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Hao Ding
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Jianan Lu
- Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Hang Zhou
- Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Lijing Zou
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Yibo Gao
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Lieju Wang
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Kai Sun
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Yue Ming
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Zhipeng Meng
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Yuan-Xiang Tao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ
| | - Min Yan
- Department of Anesthesiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
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23
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Migale R, Neumann M, Lovell-Badge R. Long-Range Regulation of Key Sex Determination Genes. Sex Dev 2021; 15:360-380. [PMID: 34753143 DOI: 10.1159/000519891] [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: 06/17/2021] [Accepted: 09/26/2021] [Indexed: 11/19/2022] Open
Abstract
The development of sexually dimorphic gonads is a unique process that starts with the specification of the bipotential genital ridges and culminates with the development of fully differentiated ovaries and testes in females and males, respectively. Research on sex determination has been mostly focused on the identification of sex determination genes, the majority of which encode for proteins and specifically transcription factors such as SOX9 in the testes and FOXL2 in the ovaries. Our understanding of which factors may be critical for sex determination have benefited from the study of human disorders of sex development (DSD) and animal models, such as the mouse and the goat, as these often replicate the same phenotypes observed in humans when mutations or chromosomic rearrangements arise in protein-coding genes. Despite the advances made so far in explaining the role of key factors such as SRY, SOX9, and FOXL2 and the genes they control, what may regulate these factors upstream is not entirely understood, often resulting in the inability to correctly diagnose DSD patients. The role of non-coding DNA, which represents 98% of the human genome, in sex determination has only recently begun to be fully appreciated. In this review, we summarize the current knowledge on the long-range regulation of 2 important sex determination genes, SOX9 and FOXL2, and discuss the challenges that lie ahead and the many avenues of research yet to be explored in the sex determination field.
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24
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Panigrahi A, O'Malley BW. Mechanisms of enhancer action: the known and the unknown. Genome Biol 2021; 22:108. [PMID: 33858480 PMCID: PMC8051032 DOI: 10.1186/s13059-021-02322-1] [Citation(s) in RCA: 103] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 03/23/2021] [Indexed: 12/13/2022] Open
Abstract
Differential gene expression mechanisms ensure cellular differentiation and plasticity to shape ontogenetic and phylogenetic diversity of cell types. A key regulator of differential gene expression programs are the enhancers, the gene-distal cis-regulatory sequences that govern spatiotemporal and quantitative expression dynamics of target genes. Enhancers are widely believed to physically contact the target promoters to effect transcriptional activation. However, our understanding of the full complement of regulatory proteins and the definitive mechanics of enhancer action is incomplete. Here, we review recent findings to present some emerging concepts on enhancer action and also outline a set of outstanding questions.
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Affiliation(s)
- Anil Panigrahi
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Bert W O'Malley
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.
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25
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Transcriptional Silencers: Driving Gene Expression with the Brakes On. Trends Genet 2021; 37:514-527. [PMID: 33712326 DOI: 10.1016/j.tig.2021.02.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 12/15/2022]
Abstract
Silencers are regulatory DNA elements that reduce transcription from their target promoters; they are the repressive counterparts of enhancers. Although discovered decades ago, and despite evidence of their importance in development and disease, silencers have been much less studied than enhancers. Recently, however, a series of papers have reported systematic studies of silencers in various model systems. Silencers are often bifunctional regulatory elements that can also act as enhancers, depending on cellular context, and are enriched for expression quantitative trait loci (eQTLs) and disease-associated variants. There is not yet evidence of a 'silencer chromatin signature', in the distribution of histone modifications or associated proteins, that is common to all silencers; instead, silencers may fall into various subclasses, acting by distinct (and possibly overlapping) mechanisms.
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26
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Palazzo A, Marsano RM. Transposable elements: a jump toward the future of expression vectors. Crit Rev Biotechnol 2021; 41:792-808. [PMID: 33622117 DOI: 10.1080/07388551.2021.1888067] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Expression vectors (EVs) are artificial nucleic acid molecules with a modular structure that allows for the transcription of DNA sequences of interest in either cellular or cell-free environments. These vectors have emerged as cross-disciplinary tools with multiple applications in an expanding Life Sciences market. The cis-regulatory sequences (CRSs) that control the transcription in EVs are typically sourced from either viruses or from characterized genes. However, the recent advancement in transposable elements (TEs) technology provides attractive alternatives that may enable a significant improvement in the design of EVs. Commonly known as "jumping genes," due to their ability to move between genetic loci, TEs are constitutive components of both eukaryotic and prokaryotic genomes. TEs harbor native CRSs that allow the regulated transcription of transposition-related genes. However, some TE-related CRSs display striking characteristics, which provides the opportunity to reconsider TEs as lead actors in the design of EVs. In this article, we provide a synopsis of the transcriptional control elements commonly found in EVs together with an extensive discussion of their advantages and limitations. We also highlight the latest findings that may allow for the implementation of TE-derived sequences in the EVs feasible, possibly improving existing vectors. By introducing this new concept of TEs as a source of regulatory sequences, we aim to stimulate a profitable discussion of the potential advantages and benefits of developing a new generation of EVs based on the use of TE-derived control sequences.
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Affiliation(s)
- Antonio Palazzo
- Laboratory of Translational Nanotechnology, "Istituto Tumori Giovanni Paolo II" I.R.C.C.S, Bari, Italy
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Kim DJ, Khoury-Hanold W, Jain PC, Klein J, Kong Y, Pope SD, Ge W, Medzhitov R, Iwasaki A. RUNX Binding Sites Are Enriched in Herpesvirus Genomes, and RUNX1 Overexpression Leads to Herpes Simplex Virus 1 Suppression. J Virol 2020; 94:e00943-20. [PMID: 32878886 PMCID: PMC7592204 DOI: 10.1128/jvi.00943-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/24/2020] [Indexed: 12/21/2022] Open
Abstract
Herpes simplex virus 1 (HSV-1) and HSV-2 can efficiently establish lifelong, transcriptionally silent latency states in sensory neurons to escape host detection. While host factors have previously been associated with long-range insulators in the viral genome, it is still unknown whether host transcription factors can repress viral genes more proximately to promote latency in dorsal root ganglion (DRG) neurons. Here, we assessed whether RUNX (runt-related transcription factor) transcription factors, which are critical in the development of sensory neurons, could be binding HSV-1 genome directly to suppress viral gene expression and lytic infection. Using previously published transcriptome sequencing data, we confirmed that mouse DRG neurons highly express Runx1 mRNA. Through computational analysis of HSV-1 and HSV-2 genomes, we observed that putative RUNX consensus binding sites (CBSs) were more enriched and more closely located to viral gene transcription start sites than would be expected by chance. We further found that RUNX CBSs were significantly more enriched among genomes of herpesviruses compared to those of nonherpesviruses. Utilizing an in vitro model of HSV-1 infection, we found that overexpressed RUNX1 could bind putative binding sites in the HSV-1 genome, repress numerous viral genes spanning all three kinetic classes, and suppress productive infection. In contrast, knockdown of RUNX1 in neuroblastoma cells induced viral gene expression and increased HSV-1 infection in vitro In sum, these data support a novel role for RUNX1 in directly binding herpesvirus genome, silencing the transcription of numerous viral genes, and ultimately limiting overall infection.IMPORTANCE Infecting 90% of the global population, HSV-1 and HSV-2 represent some of the most prevalent viruses in the world. Much of their success can be attributed to their ability to establish lifelong latent infections in the dorsal root ganglia (DRG). It is still largely unknown, however, how host transcription factors are involved in establishing this latency. Here, we report that RUNX1, expressed highly in DRG, binds HSV-1 genome, represses transcription of numerous viral genes, and suppresses productive in vitro infection. Our computational work further suggests this strategy may be used by other herpesviruses to reinforce latency in a cell-specific manner.
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Affiliation(s)
- Daniel J Kim
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - William Khoury-Hanold
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Priyanka Caroline Jain
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jonathan Klein
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Yong Kong
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Scott D Pope
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - William Ge
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Ruslan Medzhitov
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - Akiko Iwasaki
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
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Bandara TAMK, Otsuka K, Matsubara S, Shiraishi A, Satake H, Kimura AP. A dual enhancer-silencer element, DES-K16, in mouse spermatocyte-derived GC-2spd(ts) cells. Biochem Biophys Res Commun 2020; 534:1007-1012. [PMID: 33121685 DOI: 10.1016/j.bbrc.2020.10.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 10/18/2020] [Indexed: 12/23/2022]
Abstract
The multifunctionality of genome is suggested at some loci in different species but not well understood. Here we identified a DES-K16 region in an intron of the Kctd16 gene as the chromatin highly marked with epigenetic modifications of both enhancers (H3K4me1 and H3K27ac) and silencers (H3K27me3) in mouse spermatocytes. In vitro reporter gene assay demonstrated that DES-K16 exhibited significant enhancer activity in spermatocyte-derived GC-2spd(ts) and hepatic tumor-derived Hepa1-6 cells, and a deletion of this sequence in GC-2spd(ts) cells resulted in a decrease and increase of Yipf5 and Kctd16 expression, respectively. This was consistent with increased and decreased expression of Yipf5 and Kctd16, respectively, in primary spermatocytes during testis development. While known dual enhancer-silencers exert each activity in different tissues, our data suggest that DES-K16 functions as both enhancer and silencer in a single cell type, GC-2spd(ts) cells. This is the first report on a dual enhancer-silencer element which activates and suppresses gene expression in a single cell type.
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Affiliation(s)
| | - Kai Otsuka
- Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Shin Matsubara
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seikacho, Sorakugun, Kyoto, 619-0284, Japan
| | - Akira Shiraishi
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seikacho, Sorakugun, Kyoto, 619-0284, Japan
| | - Honoo Satake
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seikacho, Sorakugun, Kyoto, 619-0284, Japan
| | - Atsushi P Kimura
- Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan; Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan.
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29
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Fourier N, Zolty M, Azriel A, Tedesco D, Levi BZ. MafK Mediates Chromatin Remodeling to Silence IRF8 Expression in Non-immune Cells in a Cell Type-SpecificManner. J Mol Biol 2020; 432:4544-4560. [PMID: 32534063 DOI: 10.1016/j.jmb.2020.06.005] [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: 04/28/2020] [Revised: 06/02/2020] [Accepted: 06/05/2020] [Indexed: 11/17/2022]
Abstract
The regulation of gene expression is a result of a complex interplay between chromatin remodeling, transcription factors, and signaling molecules. Cell differentiation is accompanied by chromatin remodeling of specific loci to permanently silence genes that are not essential for the differentiated cell activity. The molecular cues that recruit the chromatin remodeling machinery are not well characterized. IRF8 is an immune-cell specific transcription factor and its expression is augmented by interferon-γ. Therefore, it serves as a model gene to elucidate the molecular mechanisms governing its silencing in non-immune cells. Ahigh-throughput shRNA library screen in IRF8 expression-restrictive cells enabled the identification of MafK as modulator of IRF8 silencing, affecting chromatin architecture. ChIP-Seq analysis revealed three MafK binding regions (-25 kb, -20 kb, and IRF8 6th intron) within the IRF8 locus. These MafK binding sites are sufficient to repress a reporter gene when cloned in genome-integrated lentiviral reporter constructs in only expression-restrictive cells. Conversely, plasmid-based constructs do not demonstrate such repressive effect. These results highlight the role of these MafK binding sites in mediating repressed chromatin assembly. Finally, a more thorough genomic analysis was performed, using CRISPR-Cas9 to delete MafK-int6 binding region in IRF8 expression-restrictive cells. Deleted clones exhibited an accessible chromatin conformation within the IRF8 locus that was accompanied by a significant increase in basal expression of IRF8 that was further induced by interferon-γ. Taken together, we identified and characterized several MafK binding elements within the IRF8 locus that mediate repressive chromatin conformation resulting in the silencing of IRF8 expression in a celltype-specific manner.
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Affiliation(s)
- Nitsan Fourier
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Maya Zolty
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Aviva Azriel
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | | | - Ben-Zion Levi
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
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30
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Kini RM. Toxinology provides multidirectional and multidimensional opportunities: A personal perspective. Toxicon X 2020; 6:100039. [PMID: 32550594 PMCID: PMC7285919 DOI: 10.1016/j.toxcx.2020.100039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 04/28/2020] [Accepted: 05/05/2020] [Indexed: 01/16/2023] Open
Abstract
In nature, toxins have evolved as weapons to capture and subdue the prey or to counter predators or competitors. When they are inadvertently injected into humans, they cause symptoms ranging from mild discomfort to debilitation and death. Toxinology is the science of studying venoms and toxins that are produced by a wide variety of organisms. In the past, the structure, function and mechanisms of most abundant and/or most toxic components were characterized to understand and to develop strategies to neutralize their toxicity. With recent technical advances, we are able to evaluate and determine the toxin profiles using transcriptomes of venom glands and proteomes of tiny amounts of venom. Enormous amounts of data from these studies have opened tremendous opportunities in many directions of basic and applied research. The lower costs for profiling venoms will further fuel the expansion of toxin database, which in turn will provide greater exciting and bright opportunities in toxin research.
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Affiliation(s)
- R. Manjunatha Kini
- Protein Science Laboratory, Department of Biological Sciences, Faculty of Science and Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Doni Jayavelu N, Jajodia A, Mishra A, Hawkins RD. Candidate silencer elements for the human and mouse genomes. Nat Commun 2020; 11:1061. [PMID: 32103011 PMCID: PMC7044160 DOI: 10.1038/s41467-020-14853-5] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/08/2020] [Indexed: 11/24/2022] Open
Abstract
The study of gene regulation is dominated by a focus on the control of gene activation or increase in the level of expression. Just as critical is the process of gene repression or silencing. Chromatin signatures have identified enhancers, however, genome-wide identification of silencers by computational or experimental approaches are lacking. Here, we first define uncharacterized cis-regulatory elements likely containing silencers and find that 41.5% of ~7500 tested elements show silencer activity using massively parallel reporter assay (MPRA). We trained a support vector machine classifier based on MPRA data to predict candidate silencers in over 100 human and mouse cell or tissue types. The predicted candidate silencers exhibit characteristics expected of silencers. Leveraging promoter-capture HiC data, we find that over 50% of silencers are interacting with gene promoters having very low to no expression. Our results suggest a general strategy for genome-wide identification and characterization of silencer elements. Identification of silencer elements by computational or experimental approaches in a genome-wide manner is still challenging. Here authors define uncharacterized cis-regulatory elements (CREs) in human and mouse genomes likely containing silencer elements, and test them in cells using massively parallel reporter assays to identify silencer elements that showed silencer activity.
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Affiliation(s)
- Naresh Doni Jayavelu
- Division of Medical Genetics, Department of Medicine, Department of Genome Sciences, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - Ajay Jajodia
- Division of Medical Genetics, Department of Medicine, Department of Genome Sciences, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - Arpit Mishra
- Division of Medical Genetics, Department of Medicine, Department of Genome Sciences, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - R David Hawkins
- Division of Medical Genetics, Department of Medicine, Department of Genome Sciences, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA, USA.
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32
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Chromatin interaction analyses elucidate the roles of PRC2-bound silencers in mouse development. Nat Genet 2020; 52:264-272. [PMID: 32094912 PMCID: PMC7869692 DOI: 10.1038/s41588-020-0581-x] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 01/15/2020] [Indexed: 12/30/2022]
Abstract
In metazoan development, lineage specific gene expression is modulated by the delicate balance between transcription activation and repression. Despite much of our knowledge in the enhancer-centered transcription activation, silencers and their roles in normal development are poorly understood. Here, we performed chromatin interaction analyses of Polycomb repressive complex 2 (PRC2), a key regulator inducing transcriptional gene silencing, to uncover silencers, their molecular identity and associated chromatin connectivity. Systematic analysis of the cis-regulatory silencer elements reveals their chromatin features and gene targeting specificity. Deletion of these PRC2-bound silencers in mice results in transcriptional derepression of their interacting genes and pleiotropic developmental phenotypes, including embryonic lethality. While functioning as PRC2-bound silencers in pluripotent cells, they can transition into active tissue-specific enhancers during development, suggesting their regulatory versatility. Our study characterizes the molecular nature of silencers, their associated chromatin architectures, and offers the exciting possibility of targeted re-activation of epigenetically silenced genes.
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33
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Silencers, Enhancers, and the Multifunctional Regulatory Genome. Trends Genet 2020; 36:149-151. [PMID: 31918861 DOI: 10.1016/j.tig.2019.12.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 12/10/2019] [Indexed: 11/22/2022]
Abstract
Negative regulation of gene expression by transcriptional silencers has been difficult to study due to limited defined examples. A new study by Gisselbrecht et al. has dramatically increased the number of identified silencers and reveals that they are bifunctional regulatory sequences that also act as gene expression-promoting enhancers.
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Gisselbrecht SS, Palagi A, Kurland JV, Rogers JM, Ozadam H, Zhan Y, Dekker J, Bulyk ML. Transcriptional Silencers in Drosophila Serve a Dual Role as Transcriptional Enhancers in Alternate Cellular Contexts. Mol Cell 2019; 77:324-337.e8. [PMID: 31704182 DOI: 10.1016/j.molcel.2019.10.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 08/15/2019] [Accepted: 10/01/2019] [Indexed: 12/26/2022]
Abstract
A major challenge in biology is to understand how complex gene expression patterns are encoded in the genome. While transcriptional enhancers have been studied extensively, few transcriptional silencers have been identified, and they remain poorly understood. Here, we used a novel strategy to screen hundreds of sequences for tissue-specific silencer activity in whole Drosophila embryos. Almost all of the transcriptional silencers that we identified were also active enhancers in other cellular contexts. These elements are bound by more transcription factors than non-silencers. A subset of these silencers forms long-range contacts with promoters. Deletion of a silencer caused derepression of its target gene. Our results challenge the common practice of treating enhancers and silencers as separate classes of regulatory elements and suggest the possibility that thousands or more bifunctional CRMs remain to be discovered in Drosophila and 104-105 in humans.
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Affiliation(s)
- Stephen S Gisselbrecht
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Alexandre Palagi
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Doctoral School of Life and Health Sciences, University of Nice Sophia Antipolis, 06560 Valbonne, France
| | - Jesse V Kurland
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Julia M Rogers
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, MA 02138, USA
| | - Hakan Ozadam
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Ye Zhan
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Martha L Bulyk
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, MA 02138, USA; Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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35
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Sirisena ND, Samaranayake N, Dissanayake VHW. Electrophoretic mobility shift assays implicate XRCC2:rs3218550C>T as a potential low-penetrant susceptibility allele for sporadic breast cancer. BMC Res Notes 2019; 12:476. [PMID: 31370865 PMCID: PMC6676616 DOI: 10.1186/s13104-019-4512-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 07/23/2019] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE A previous study undertaken at our centre to identify common genetic variants associated with sporadic breast cancer in Sri Lankan women showed that the T allele of rs3218550, located in the 3'untranslated region of X-ray repair cross-complementing gene-2 (XRCC2), increased breast cancer risk by 1.5-fold. Dual luciferase reporter assays performed in MCF-7 breast cancer cells showed a putative transcriptional repressor effect exerted mainly by the T allele. Electrophoretic mobility shift assays were conducted to further investigate the interaction of this variant with DNA-binding protein, using nuclear protein extracts derived from MCF-7 cells. RESULTS An allele-specific differential binding was observed. The T allele resulted in differential DNA-protein complex binding as evidenced by the presence of multiple bands of increased intensity compared to the wild-type C allele. This implies possible alteration in binding of regulatory proteins by the variant allele. These results implicate XRCC2:rs3218550C>T as a potential low-penetrant susceptibility allele for sporadic breast cancer. XRCC2 is known to play an essential role in homologous recombination repair of DNA double-strand breaks. It is plausible that this variant may be exerting regulatory effects on XRCC2 gene expression leading to altered DNA repair capacity. Further functional studies are warranted to validate this finding.
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Affiliation(s)
- Nirmala D Sirisena
- Human Genetics Unit, Faculty of Medicine, University of Colombo, No. 25 Kynsey Road, Colombo 8, 00800, Sri Lanka.
| | - Nilakshi Samaranayake
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo 8, 00800, Sri Lanka
| | - Vajira H W Dissanayake
- Human Genetics Unit, Faculty of Medicine, University of Colombo, No. 25 Kynsey Road, Colombo 8, 00800, Sri Lanka
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36
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Mookerjee-Basu J, Hua X, Ge L, Nicolas E, Li Q, Czyzewicz P, Zhongping D, Peri S, FuxmanBass JI, Walhout AJM, Kappes DJ. Functional Conservation of a Developmental Switch in Mammals since the Jurassic Age. Mol Biol Evol 2019; 36:39-53. [PMID: 30295892 DOI: 10.1093/molbev/msy191] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
ThPOK is a "master regulator" of T lymphocyte lineage choice, whose presence or absence is sufficient to dictate development to the CD4 or CD8 lineages, respectively. Induction of ThPOK is transcriptionally regulated, via a lineage-specific silencer element, SilThPOK. Here, we take advantage of the available genome sequence data as well as site-specific gene targeting technology, to evaluate the functional conservation of ThPOK regulation across mammalian evolution, and assess the importance of motif grammar (order and orientation of TF binding sites) on SilThPOK function in vivo. We make three important points: First, the SilThPOK is present in marsupial and placental mammals, but is not found in available genome assemblies of nonmammalian vertebrates, indicating that it arose after divergence of mammals from other vertebrates. Secondly, by replacing the murine SilThPOK in situ with its marsupial equivalent using a knockin approach, we demonstrate that the marsupial SilThPOK supports correct CD4 T lymphocyte lineage-specification in mice. To our knowledge, this is the first in vivo demonstration of functional equivalency for a silencer element between marsupial and placental mammals using a definitive knockin approach. Finally, we show that alteration of the position/orientation of a highly conserved region within the murine SilThPOK is sufficient to destroy silencer activity in vivo, demonstrating that motif grammar of this "solid" synteny block is critical for silencer function. Dependence of SilThPOK function on motif grammar conserved since the mid-Jurassic age, 165 Ma, suggests that the SilThPOK operates as a silenceosome, by analogy with the previously proposed enhanceosome model.
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Affiliation(s)
- Jayati Mookerjee-Basu
- Blood Cell Development and Cancer Program, Fox Chase Cancer Center, Philadelphia, PA
| | - Xiang Hua
- Blood Cell Development and Cancer Program, Fox Chase Cancer Center, Philadelphia, PA
| | - Lu Ge
- Blood Cell Development and Cancer Program, Fox Chase Cancer Center, Philadelphia, PA
| | - Emmanuelle Nicolas
- Blood Cell Development and Cancer Program, Fox Chase Cancer Center, Philadelphia, PA
| | - Qin Li
- Blood Cell Development and Cancer Program, Fox Chase Cancer Center, Philadelphia, PA
| | - Philip Czyzewicz
- Blood Cell Development and Cancer Program, Fox Chase Cancer Center, Philadelphia, PA
| | - Dai Zhongping
- Blood Cell Development and Cancer Program, Fox Chase Cancer Center, Philadelphia, PA
| | - Suraj Peri
- Blood Cell Development and Cancer Program, Fox Chase Cancer Center, Philadelphia, PA
| | - Juan I FuxmanBass
- Program in Systems Biology, Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Albertha J M Walhout
- Program in Systems Biology, Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Dietmar J Kappes
- Blood Cell Development and Cancer Program, Fox Chase Cancer Center, Philadelphia, PA
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37
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Doan RN, Shin T, Walsh CA. Evolutionary Changes in Transcriptional Regulation: Insights into Human Behavior and Neurological Conditions. Annu Rev Neurosci 2019; 41:185-206. [PMID: 29986162 DOI: 10.1146/annurev-neuro-080317-062104] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Understanding the biological basis for human-specific cognitive traits presents both immense challenges and unique opportunities. Although the question of what makes us human has been investigated with several different methods, the rise of comparative genomics, epigenomics, and medical genetics has provided tools to help narrow down and functionally assess the regions of the genome that seem evolutionarily relevant along the human lineage. In this review, we focus on how medical genetic cases have provided compelling functional evidence for genes and loci that appear to have interesting evolutionary signatures in humans. Furthermore, we examine a special class of noncoding regions, human accelerated regions (HARs), that have been suggested to show human-lineage-specific divergence, and how the use of clinical and population data has started to provide functional information to examine these regions. Finally, we outline methods that provide new insights into functional noncoding sequences in evolution.
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Affiliation(s)
- Ryan N Doan
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts 02115, USA; .,Allen Discovery Center for Human Brain Evolution, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Taehwan Shin
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts 02115, USA; .,Allen Discovery Center for Human Brain Evolution, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Christopher A Walsh
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts 02115, USA; .,Allen Discovery Center for Human Brain Evolution, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115, USA.,Departments of Pediatrics and Neurology, Harvard Medical School, Boston, Massachusetts 02138, USA
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38
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Repele A, Krueger S, Bhattacharyya T, Tuineau MY. The regulatory control of Cebpa enhancers and silencers in the myeloid and red-blood cell lineages. PLoS One 2019; 14:e0217580. [PMID: 31181110 PMCID: PMC6557489 DOI: 10.1371/journal.pone.0217580] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 05/14/2019] [Indexed: 12/31/2022] Open
Abstract
Cebpa encodes a transcription factor (TF) that plays an instructive role in the development of multiple myeloid lineages. The expression of Cebpa itself is finely modulated, as Cebpa is expressed at high and intermediate levels in neutrophils and macrophages respectively and downregulated in non-myeloid lineages. The cis-regulatory logic underlying the lineage-specific modulation of Cebpa's expression level is yet to be fully characterized. Previously, we had identified 6 new cis-regulatory modules (CRMs) in a 78kb region surrounding Cebpa. We had also inferred the TFs that regulate each CRM by fitting a sequence-based thermodynamic model to a comprehensive reporter activity dataset. Here, we report the cis-regulatory logic of Cebpa CRMs at the resolution of individual binding sites. We tested the binding sites and functional roles of inferred TFs by designing and constructing mutated CRMs and comparing theoretical predictions of their activity against empirical measurements in a myeloid cell line. The enhancers were confirmed to be activated by combinations of PU.1, C/EBP family TFs, Egr1, and Gfi1 as predicted by the model. We show that silencers repress the activity of the proximal promoter in a dominant manner in G1ME cells, which are derived from the red-blood cell lineage. Dominant repression in G1ME cells can be traced to binding sites for GATA and Myb, a motif shared by all of the silencers. Finally, we demonstrate that GATA and Myb act redundantly to silence the proximal promoter. These results indicate that dominant repression is a novel mechanism for resolving hematopoietic lineages. Furthermore, Cebpa has a fail-safe cis-regulatory architecture, featuring several functionally similar CRMs, each of which contains redundant binding sites for multiple TFs. Lastly, by experimentally demonstrating the predictive ability of our sequence-based thermodynamic model, this work highlights the utility of this computational approach for understanding mammalian gene regulation.
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Affiliation(s)
- Andrea Repele
- Department of Biology, University of North Dakota, Grand Forks, ND, United States of America
| | - Shawn Krueger
- Department of Biology, University of North Dakota, Grand Forks, ND, United States of America
| | - Tapas Bhattacharyya
- Department of Biology, University of North Dakota, Grand Forks, ND, United States of America
| | - Michelle Y Tuineau
- Department of Biology, University of North Dakota, Grand Forks, ND, United States of America
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Zhang L, Qin LN, Zeng ZR, Wu CZ, Gong YY, Liu LH, Cao FQ. Molecular identification of a root apical cell-specific and stress-responsive enhancer from an Arabidopsis enhancer trap line. PLANT METHODS 2019; 15:8. [PMID: 30733820 PMCID: PMC6354418 DOI: 10.1186/s13007-019-0393-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 01/21/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Plant root apex is the major part to direct the root growth and development by responding to various signals/cues from internal and soil environments. To study and understand root system biology particularly at a molecular and cellular level, an Arabidopsis T-DNA insertional enhancer trap line J3411 expressing reporters (GFP) only in the root tip was adopted in this study to isolate a DNA fragment. RESULTS Using nested PCR, DNA sequencing and sequence homology search, the T-DNA insertion site(s) and its flanking genes were characterised in J3411 line. Subsequently, a 2000 bp plant DNA-fragment (Ertip1) upstream of the insert position of the coding T-DNA was in silico analysed, revealing certain putative promoter/enhancer cis-regulatory elements. Cloning and transformation of this DNA fragment and its truncated segments tagged with or without 35S minimal promoter (35Smini), all of which were fused with a GFP or GUS reporter, allowed to detect GFP and GUS expression mediated only by Ertip1 + 35mini (PErtip1+35Smini) specifically in the Arabidopsis root tip region. The PErtip1+35Smini activity was further tested to be strong and stable under many different growth conditions but suppressed by cold, salt, alkaline pH and higher ammonium and phosphorus. CONCLUSION This work describes a promising strategy to isolate a tissue-/cell-specific enhancer sequence from the enhancer trap lines, which are publically available. The reported synthetic promoter i.e. PErtip1+35Smini may provide a valuable and potent molecular-tool for comprehensive investigation of a gene function related to root growth and development as well as molecular engineering of root-architectural formation aiming to improve plant growth.
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Affiliation(s)
- Lei Zhang
- 1Key Laboratory of Plant-Soil Interaction, MOE, Center for Resources, Environment and Food Security, College Resources and Environmental Sciences, China Agricultural University, Beijing, 100193 China
| | - Li-Na Qin
- 1Key Laboratory of Plant-Soil Interaction, MOE, Center for Resources, Environment and Food Security, College Resources and Environmental Sciences, China Agricultural University, Beijing, 100193 China
- Zhaoyuan Agricultural Technology Extension Centre, Zhaoyuan, 265400 Shandong China
| | - Zi-Rui Zeng
- 1Key Laboratory of Plant-Soil Interaction, MOE, Center for Resources, Environment and Food Security, College Resources and Environmental Sciences, China Agricultural University, Beijing, 100193 China
| | - Chang-Zheng Wu
- 1Key Laboratory of Plant-Soil Interaction, MOE, Center for Resources, Environment and Food Security, College Resources and Environmental Sciences, China Agricultural University, Beijing, 100193 China
| | - Yuan-Yong Gong
- 1Key Laboratory of Plant-Soil Interaction, MOE, Center for Resources, Environment and Food Security, College Resources and Environmental Sciences, China Agricultural University, Beijing, 100193 China
- 3Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture, The Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014 China
| | - Lai-Hua Liu
- 1Key Laboratory of Plant-Soil Interaction, MOE, Center for Resources, Environment and Food Security, College Resources and Environmental Sciences, China Agricultural University, Beijing, 100193 China
| | - Feng-Qiu Cao
- 4Shanghai Centre for Plant Stress Biology of Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 201602 China
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Singh KP, Miaskowski C, Dhruva AA, Flowers E, Kober KM. Mechanisms and Measurement of Changes in Gene Expression. Biol Res Nurs 2018; 20:369-382. [PMID: 29706088 PMCID: PMC6346310 DOI: 10.1177/1099800418772161] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Research on gene expression (GE) provides insights into the physiology of a cell or group of cells at a given point in time. Studies of changes in GE can be used to identify patients at higher risk for various medical conditions, a higher symptom burden, and/or the adverse consequences associated with various treatments. The aims of this article are as follows: (1) to describe the different types of RNA transcripts, (2) to describe the processes involved in GE (i.e., RNA transcription, epigenetics, and posttranscriptional modifications), (3) to describe common sources of variation in GE, (4) to describe the most common methods used to measure GE, and (5) to discuss factors to consider when choosing tissue for a GE study. This article begins with an overview of the mechanisms involved in GE. Then, the factors that can influence the findings from GE experiments (e.g., tissue specificity, host age, host gender, and time of sample collection) are described and potential solutions are presented. This article concludes with a discussion of how the types of tissue used in GE studies can affect study findings. Given that the costs associated with the measurement of changes in GE are decreasing and the methods to analyze GE data are becoming easier to use, nurse scientists need to understand the basic principles that underlie any GE study.
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Affiliation(s)
- Komal P. Singh
- Department of Physiological Nursing, School of Nursing, University of California, San Francisco, CA, USA
| | - Christine Miaskowski
- Department of Physiological Nursing, School of Nursing, University of California, San Francisco, CA, USA
| | - Anand A. Dhruva
- School of Medicine, University of California, San Francisco, CA, USA
| | - Elena Flowers
- Department of Physiological Nursing, School of Nursing, University of California, San Francisco, CA, USA
| | - Kord M. Kober
- Department of Physiological Nursing, School of Nursing, University of California, San Francisco, CA, USA
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Yadav DK, Shrestha S, Dadhwal G, Chandak GR. Identification and characterization of cis-regulatory elements 'insulator and repressor' in PPARD gene. Epigenomics 2018; 10:613-627. [PMID: 29583017 DOI: 10.2217/epi-2017-0139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
AIM Identification and functional characterization of cis-regulatory elements in human PPARD gene. METHODS We used various bioinformatic tools on the publicly available human genome and Encyclopedia of DNA Elements databases to explore potential cis-regulatory elements in PPARD gene region. RESULTS We predicted an insulator and an enhancer element in intron 2 of PPARD gene. Functional characterization using transient transfection, reporter assay and CTCF binding confirmed the insulator status. However, the predicted enhancer element showed repressor/silencer activity. Finally, we observed a potential interaction between these two cis-regulatory elements which is in agreement with 5C-Encyclopedia of DNA Elements data. CONCLUSION We report two functionally validated cis-regulatory elements in PPARD gene which will aid in understanding its regulation and role in metabolic functions.
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Affiliation(s)
- Dilip K Yadav
- Genomic Research on Complex Diseases (GRC Group), CSIR-Centre for Cellular & Molecular Biology, Hyderabad, Telangana, 500 007, India
| | - Smeeta Shrestha
- Genomic Research on Complex Diseases (GRC Group), CSIR-Centre for Cellular & Molecular Biology, Hyderabad, Telangana, 500 007, India.,Building No.7, School of Basic & Applied Sciences, Dayananda Sagar University, Shavige Malleshwara Hills, Kumaraswamy Layout, Bangalore 560 078, Karnataka, India
| | - Gunjan Dadhwal
- Genomic Research on Complex Diseases (GRC Group), CSIR-Centre for Cellular & Molecular Biology, Hyderabad, Telangana, 500 007, India.,Departement de Biochimie et Medecine Moleculaire, Universite de Montreal, Montreal, Quebec H3T 1J4, Canada
| | - Giriraj R Chandak
- Genomic Research on Complex Diseases (GRC Group), CSIR-Centre for Cellular & Molecular Biology, Hyderabad, Telangana, 500 007, India
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Abstract
Naturally occurring, large deletions in the β-globin locus result in hereditary persistence of fetal hemoglobin, a condition that mitigates the clinical severity of sickle cell disease (SCD) and β-thalassemia. We designed a clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) (CRISPR/Cas9) strategy to disrupt a 13.6-kb genomic region encompassing the δ- and β-globin genes and a putative γ-δ intergenic fetal hemoglobin (HbF) silencer. Disruption of just the putative HbF silencer results in a mild increase in γ-globin expression, whereas deletion or inversion of a 13.6-kb region causes a robust reactivation of HbF synthesis in adult erythroblasts that is associated with epigenetic modifications and changes in chromatin contacts within the β-globin locus. In primary SCD patient-derived hematopoietic stem/progenitor cells, targeting the 13.6-kb region results in a high proportion of γ-globin expression in erythroblasts, increased HbF synthesis, and amelioration of the sickling cell phenotype. Overall, this study provides clues for a potential CRISPR/Cas9 genome editing approach to the therapy of β-hemoglobinopathies.
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Zahratka JA, Shao Y, Shaw M, Todd K, Formica SV, Khrestian M, Montine T, Leverenz JB, Bekris LM. Regulatory region genetic variation is associated with FYN expression in Alzheimer's disease. Neurobiol Aging 2016; 51:43-53. [PMID: 28033507 DOI: 10.1016/j.neurobiolaging.2016.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 10/26/2016] [Accepted: 11/08/2016] [Indexed: 12/15/2022]
Abstract
Neurofibrillary tangles (NFTs), composed of hyperphosphorylated tau, are a key pathologic feature of Alzheimer's disease (AD). Tau phosphorylation is under the control of multiple kinases and phosphatases, including Fyn. Previously, our group found an association between 2 regulatory single nucleotide polymorphisms in the FYN gene with increased tau levels in the cerebrospinal fluid. In this study, we hypothesized that Fyn expression in the brain is influenced by AD status and genetic content. We found that Fyn protein, but not messenger RNA, levels were increased in AD patients compared to cognitively normal controls and are associated with regulatory region single nucleotide polymorphisms. In addition, the expression of the FYN 3'UTR can decrease expression in multiple cell lines, suggesting this regulatory region plays an important role in FYN expression. Taken together, these data suggest that FYN expression is regulated according to AD status and regulatory region haplotype, and genetic variants may be instrumental in the development of neurofibrillary tangles in AD and other tauopathies.
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Affiliation(s)
- Jeffrey A Zahratka
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.
| | - Yvonne Shao
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - McKenzie Shaw
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Kaitlin Todd
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Shane V Formica
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Maria Khrestian
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Thomas Montine
- Department of Pathology, Stanford University, Palo Alto, CA, USA
| | - James B Leverenz
- Lou Ruvo Center for Brain Health, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Lynn M Bekris
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
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Weber B, Zicola J, Oka R, Stam M. Plant Enhancers: A Call for Discovery. TRENDS IN PLANT SCIENCE 2016; 21:974-987. [PMID: 27593567 DOI: 10.1016/j.tplants.2016.07.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/18/2016] [Accepted: 07/28/2016] [Indexed: 05/12/2023]
Abstract
Higher eukaryotes typically contain many different cell types, displaying different cellular functions that are influenced by biotic and abiotic cues. The different functions are characterized by specific gene expression patterns mediated by regulatory sequences such as transcriptional enhancers. Recent genome-wide approaches have identified thousands of enhancers in animals, reviving interest in enhancers in gene regulation. Although the regulatory roles of plant enhancers are as crucial as those in animals, genome-wide approaches have only very recently been applied to plants. Here we review characteristics of enhancers at the DNA and chromatin level in plants and other species, their similarities and differences, and techniques widely used for genome-wide discovery of enhancers in animal systems that can be implemented in plants.
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Affiliation(s)
- Blaise Weber
- Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Johan Zicola
- Max Planck Institute for Plant Breeding Research, Department Plant Developmental Biology, Carl-von-Linné-Weg 10, 50829 Köln, Germany
| | - Rurika Oka
- Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Maike Stam
- Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
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Han SX, Kwong S, Ge R, Kolatkar PR, Woods AE, Blanchet G, Kini RM. Regulation of expression of venom toxins: silencing of prothrombin activator trocarin D by AG‐rich motifs. FASEB J 2016; 30:2411-25. [DOI: 10.1096/fj.201600213r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 02/29/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Summer Xia Han
- Department of Biological SciencesNational University of SingaporeSingapore
| | - Shiyang Kwong
- Department of Biological SciencesNational University of SingaporeSingapore
| | - Ruowen Ge
- Department of Biological SciencesNational University of SingaporeSingapore
| | - Prasanna R. Kolatkar
- Qatar Biomedical Research Institute, Hamad Bin Khalifa University, Qatar Foundation for Education, Science, and Community DevelopmentDohaQatar
| | - Anthony E. Woods
- School of Pharmacy and Medical SciencesUniversity of South AustraliaAdelaideSouth AustraliaAustralia
| | - Guillaume Blanchet
- Department of Biological SciencesNational University of SingaporeSingapore
| | - R. Manjunatha Kini
- Department of Biological SciencesNational University of SingaporeSingapore
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Bertolino E, Reinitz J, Manu. The analysis of novel distal Cebpa enhancers and silencers using a transcriptional model reveals the complex regulatory logic of hematopoietic lineage specification. Dev Biol 2016; 413:128-44. [PMID: 26945717 DOI: 10.1016/j.ydbio.2016.02.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/13/2016] [Accepted: 02/15/2016] [Indexed: 11/25/2022]
Abstract
C/EBPα plays an instructive role in the macrophage-neutrophil cell-fate decision and its expression is necessary for neutrophil development. How Cebpa itself is regulated in the myeloid lineage is not known. We decoded the cis-regulatory logic of Cebpa, and two other myeloid transcription factors, Egr1 and Egr2, using a combined experimental-computational approach. With a reporter design capable of detecting both distal enhancers and silencers, we analyzed 46 putative cis-regulatory modules (CRMs) in cells representing myeloid progenitors, and derived early macrophages or neutrophils. In addition to novel enhancers, this analysis revealed a surprisingly large number of silencers. We determined the regulatory roles of 15 potential transcriptional regulators by testing 32,768 alternative sequence-based transcriptional models against CRM activity data. This comprehensive analysis allowed us to infer the cis-regulatory logic for most of the CRMs. Silencer-mediated repression of Cebpa was found to be effected mainly by TFs expressed in non-myeloid lineages, highlighting a previously unappreciated contribution of long-distance silencing to hematopoietic lineage resolution. The repression of Cebpa by multiple factors expressed in alternative lineages suggests that hematopoietic genes are organized into densely interconnected repressive networks instead of hierarchies of mutually repressive pairs of pivotal TFs. More generally, our results demonstrate that de novo cis-regulatory dissection is feasible on a large scale with the aid of transcriptional modeling. Current address: Department of Biology, University of North Dakota, 10 Cornell Street, Stop 9019, Grand Forks, ND 58202-9019, USA.
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Affiliation(s)
- Eric Bertolino
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA.
| | - John Reinitz
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA; Department of Statistics, The University of Chicago, Chicago, IL 60637, USA; Department of Ecology and Evolution and Institute of Genomics and Systems Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Manu
- Department of Ecology and Evolution and Institute of Genomics and Systems Biology, The University of Chicago, Chicago, IL 60637, USA; Department of Biology, University of North Dakota, 10 Cornell Street, Stop 9019, Grand Forks, ND 58202-9019, USA.
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Ramachandran P, Palidwor GA, Perkins TJ. BIDCHIPS: bias decomposition and removal from ChIP-seq data clarifies true binding signal and its functional correlates. Epigenetics Chromatin 2015; 8:33. [PMID: 26388941 PMCID: PMC4574076 DOI: 10.1186/s13072-015-0028-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/07/2015] [Indexed: 12/24/2022] Open
Abstract
Background Unraveling transcriptional regulatory networks is a central problem in molecular biology and, in this quest, chromatin immunoprecipitation and sequencing (ChIP-seq) technology has given us the unprecedented ability to identify sites of protein-DNA binding and histone modification genome wide. However, multiple systemic and procedural biases hinder harnessing the full potential of this technology. Previous studies have addressed this problem, but a thorough characterization of different, interacting biases on ChIP-seq signals is still lacking. Results Here, we present a novel framework where the genome-wide ChIP-seq signal is viewed as being quantifiably influenced by different, measurable sources of bias, which can then be computationally subtracted away. We use a compendium of 123 human ENCODE ChIP-seq datasets to build regression models that tell us how much of a ChIP-seq signal can be attributed to mappability, GC-content, chromatin accessibility, and factors represented in input DNA and IgG controls. When we use the model to separate out these non-binding influences from the ChIP-seq signal, we obtain a purified signal that associates better to TF-DNA-binding motifs than do other measures of peak significance. We also carry out a multiscale analysis that reveals how ChIP-seq signal biases differ across different scales. Finally, we investigate previously reported associations between gene expression and ChIP-seq signals at transcription start sites. We show that our model can be used to discriminate ChIP-seq signals that are truly related to gene expression from those that are merely correlated by virtue of bias—in particular, chromatin accessibility bias, which shows up in ChIP-seq signals and also relates to gene expression. Conclusions Our study provides new insights into the behavior of ChIP-seq signal biases and proposes a novel mitigation framework that improves results compared to existing techniques. With ChIP-seq now being the central technology for studying transcriptional regulation, it is most crucial to accurately characterize, quantify, and adjust for the genome-wide effects of biases affecting ChIP-seq. Our study also emphasizes that properly accounting for confounders in ChIP-seq data is of paramount importance for obtaining biologically accurate insights into the workings of the complex regulatory mechanisms in living organisms. R and MATLAB packages implementing the framework can be obtained from http://www.perkinslab.ca/Software.html. Electronic supplementary material The online version of this article (doi:10.1186/s13072-015-0028-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Parameswaran Ramachandran
- Regenerative Medicine Program, Ottawa Hospital Research Institute, K1H 8L6 Ottawa, Canada ; Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, K1H 8M5 Ottawa, Canada
| | - Gareth A Palidwor
- Regenerative Medicine Program, Ottawa Hospital Research Institute, K1H 8L6 Ottawa, Canada
| | - Theodore J Perkins
- Regenerative Medicine Program, Ottawa Hospital Research Institute, K1H 8L6 Ottawa, Canada ; Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, K1H 8M5 Ottawa, Canada
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Russo MT, Annunziata R, Sanges R, Ferrante MI, Falciatore A. The upstream regulatory sequence of the light harvesting complex Lhcf2 gene of the marine diatom Phaeodactylum tricornutum enhances transcription in an orientation- and distance-independent fashion. Mar Genomics 2015; 24 Pt 1:69-79. [PMID: 26117181 DOI: 10.1016/j.margen.2015.06.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 05/31/2015] [Accepted: 06/17/2015] [Indexed: 10/23/2022]
Abstract
Diatoms are a key phytoplankton group in the contemporary ocean, showing extraordinary adaptation capacities to rapidly changing environments. The recent availability of whole genome sequences from representative species has revealed distinct features in their genomes, like novel combinations of genes encoding distinct metabolisms and a significant number of diatom-specific genes. However, the regulatory mechanisms driving diatom gene expression are still largely uncharacterized. Considering the wide variety of fields of study orbiting diatoms, ranging from ecology, evolutionary biology to biotechnology, it is thus essential to increase our understanding of fundamental gene regulatory processes such as transcriptional regulation. To this aim, we explored the functional properties of the 5'-flanking region of the Phaeodatylum tricornutum Lhcf2 gene, encoding a member of the Light Harvesting Complex superfamily and we showed that this region enhances transcription of a GUS reporter gene in an orientation- and distance-independent fashion. This represents the first example of a cis-regulatory sequence with enhancer-like features discovered in diatoms and it is instrumental for the generation of novel genetic tools and diatom exploitation in different areas of study.
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Affiliation(s)
| | - Rossella Annunziata
- Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine, UMR 7238, F-75006 Paris, France; CNRS, UMR 7238, F-75006 Paris, France
| | - Remo Sanges
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
| | | | - Angela Falciatore
- Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine, UMR 7238, F-75006 Paris, France; CNRS, UMR 7238, F-75006 Paris, France.
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Functional validation of a constitutive autonomous silencer element. PLoS One 2015; 10:e0124588. [PMID: 25910277 PMCID: PMC4409358 DOI: 10.1371/journal.pone.0124588] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 03/14/2015] [Indexed: 11/19/2022] Open
Abstract
Sequences of the genome that are capable of silencing gene expression are thought to play a key role in gene regulation. However, very few silencer elements capable of functioning in mammalian cells have been described, and only a fraction of these have been tested for the ability to function in an autonomous fashion. We report here the characterization and functional validation of a constitutive autonomous silencer element from the human genome called T39, and the comparison of T39 to three other putative silencer elements previously described by others. Functional analysis included one assay for enhancer-blocking insulator activity and two independent assays for silencer activity, all based on stable transfection and comparison to a neutral spacer control. In erythroid K562 cells, T39 exhibited potent silencer activity, the previously described element PRE2-S5 exhibited modest silencer activity, and the two other previously described elements exhibited no silencer activity. T39 was further found to be capable of silencing three disparate promoters, of silencing gene expression in three disparate cell lines, and of functioning as a single copy in a topology-independent manner. Of the four elements analyzed, only T39 exhibits a constitutive pattern of DNase hypersensitivity and binding by CTCF. In its native location the T39 element also exhibits a unique interaction profile with a subset of distal putative regulatory elements. Taken together, these studies validate T39 as a constitutive autonomous silencer, identify T39 as a defined control for future studies of other regulatory elements such as insulators, and provide a basic chromatin profile for one highly potent silencer element.
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