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Zolotarev N, Fedotova A, Kyrchanova O, Bonchuk A, Penin AA, Lando AS, Eliseeva IA, Kulakovskiy IV, Maksimenko O, Georgiev P. Architectural proteins Pita, Zw5,and ZIPIC contain homodimerization domain and support specific long-range interactions in Drosophila. Nucleic Acids Res 2016; 44:7228-41. [PMID: 27137890 PMCID: PMC5009728 DOI: 10.1093/nar/gkw371] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 04/23/2016] [Indexed: 12/18/2022] Open
Abstract
According to recent models, as yet poorly studied architectural proteins appear to be required for local regulation of enhancer-promoter interactions, as well as for global chromosome organization. Transcription factors ZIPIC, Pita and Zw5 belong to the class of chromatin insulator proteins and preferentially bind to promoters near the TSS and extensively colocalize with cohesin and condensin complexes. ZIPIC, Pita and Zw5 are structurally similar in containing the N-terminal zinc finger-associated domain (ZAD) and different numbers of C2H2-type zinc fingers at the C-terminus. Here we have shown that the ZAD domains of ZIPIC, Pita and Zw5 form homodimers. In Drosophila transgenic lines, these proteins are able to support long-distance interaction between GAL4 activator and the reporter gene promoter. However, no functional interaction between binding sites for different proteins has been revealed, suggesting that such interactions are highly specific. ZIPIC facilitates long-distance stimulation of the reporter gene by GAL4 activator in yeast model system. Many of the genomic binding sites of ZIPIC, Pita and Zw5 are located at the boundaries of topologically associated domains (TADs). Thus, ZAD-containing zinc-finger proteins can be attributed to the class of architectural proteins.
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Affiliation(s)
- Nikolay Zolotarev
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, Moscow 119334, Russia
| | - Anna Fedotova
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, Moscow 119334, Russia
| | - Olga Kyrchanova
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, Moscow 119334, Russia
| | - Artem Bonchuk
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, Moscow 119334, Russia
| | - Aleksey A Penin
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119991, Russia; Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow 127051 Russia; Department of Genetics, Faculty of Biology, Moscow State University, Moscow 119991, Russia
| | - Andrey S Lando
- Moscow Institute of Physics and Technology (State University), Institutskiy per. 9, Dolgoprudny, Moscow Region 141700, Russia Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkina str. 3, Moscow, GSP-1, 119991, Russia
| | - Irina A Eliseeva
- Group of Protein Biosynthesis Regulation, Institute of Protein Research, Institutskaya str. 4, Pushchino 142290, Russia
| | - Ivan V Kulakovskiy
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkina str. 3, Moscow, GSP-1, 119991, Russia Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilova str. 32, Moscow, GSP-1, 119991, Russia
| | - Oksana Maksimenko
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, Moscow 119334, Russia
| | - Pavel Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, Moscow 119334, Russia
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Blick AJ, Mayer-Hirshfeld I, Malibiran BR, Cooper MA, Martino PA, Johnson JE, Bateman JR. The Capacity to Act in Trans Varies Among Drosophila Enhancers. Genetics 2016; 203:203-18. [PMID: 26984057 PMCID: PMC4858774 DOI: 10.1534/genetics.115.185645] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 03/07/2016] [Indexed: 01/10/2023] Open
Abstract
The interphase nucleus is organized such that genomic segments interact in cis, on the same chromosome, and in trans, between different chromosomes. In Drosophila and other Dipterans, extensive interactions are observed between homologous chromosomes, which can permit enhancers and promoters to communicate in trans Enhancer action in trans has been observed for a handful of genes in Drosophila, but it is as yet unclear whether this is a general property of all enhancers or specific to a few. Here, we test a collection of well-characterized enhancers for the capacity to act in trans Specifically, we tested 18 enhancers that are active in either the eye or wing disc of third instar Drosophila larvae and, using two different assays, found evidence that each enhancer can act in trans However, the degree to which trans-action was supported varied greatly between enhancers. Quantitative analysis of enhancer activity supports a model wherein an enhancer's strength of transcriptional activation is a major determinant of its ability to act in trans, but that additional factors may also contribute to an enhancer's trans-activity. In sum, our data suggest that a capacity to activate a promoter on a paired chromosome is common among Drosophila enhancers.
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Affiliation(s)
- Amanda J Blick
- Biology Department, Bowdoin College, Brunswick, Maine 04011
| | | | | | | | | | | | - Jack R Bateman
- Biology Department, Bowdoin College, Brunswick, Maine 04011
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Ali T, Renkawitz R, Bartkuhn M. Insulators and domains of gene expression. Curr Opin Genet Dev 2016; 37:17-26. [PMID: 26802288 DOI: 10.1016/j.gde.2015.11.009] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 11/20/2015] [Accepted: 11/25/2015] [Indexed: 01/07/2023]
Abstract
The genomic organization into active and inactive chromatin domains imposes specific requirements for having domain boundaries to prohibit interference between the opposing activities of neighbouring domains. These boundaries provide an insulator function by binding architectural proteins that mediate long-range interactions. Among these, CTCF plays a prominent role in establishing chromatin loops (between pairs of CTCF binding sites) through recruiting cohesin. CTCF-mediated long-range interactions are integral for a multitude of topological features of interphase chromatin, such as the formation of topologically associated domains, domain insulation, enhancer blocking and even enhancer function.
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Affiliation(s)
- Tamer Ali
- Institute for Genetics, Justus-Liebig-University, Heinrich-Buff-Ring 58, D35392 Giessen, Germany
| | - Rainer Renkawitz
- Institute for Genetics, Justus-Liebig-University, Heinrich-Buff-Ring 58, D35392 Giessen, Germany.
| | - Marek Bartkuhn
- Institute for Genetics, Justus-Liebig-University, Heinrich-Buff-Ring 58, D35392 Giessen, Germany
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Babarinde IA, Saitou N. Genomic Locations of Conserved Noncoding Sequences and Their Proximal Protein-Coding Genes in Mammalian Expression Dynamics. Mol Biol Evol 2016; 33:1807-17. [PMID: 27017584 DOI: 10.1093/molbev/msw058] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Experimental studies have found the involvement of certain conserved noncoding sequences (CNSs) in the regulation of the proximal protein-coding genes in mammals. However, reported cases of long range enhancer activities and inter-chromosomal regulation suggest that proximity of CNSs to protein-coding genes might not be important for regulation. To test the importance of the CNS genomic location, we extracted the CNSs conserved between chicken and four mammalian species (human, mouse, dog, and cattle). These CNSs were confirmed to be under purifying selection. The intergenic CNSs are often found in clusters in gene deserts, where protein-coding genes are in paucity. The distribution pattern, ChIP-Seq, and RNA-Seq data suggested that the CNSs are more likely to be regulatory elements and not corresponding to long intergenic noncoding RNAs. Physical distances between CNS and their nearest protein coding genes were well conserved between human and mouse genomes, and CNS-flanking genes were often found in evolutionarily conserved genomic neighborhoods. ChIP-Seq signal and gene expression patterns also suggested that CNSs regulate nearby genes. Interestingly, genes with more CNSs have more evolutionarily conserved expression than those with fewer CNSs. These computationally obtained results suggest that the genomic locations of CNSs are important for their regulatory functions. In fact, various kinds of evolutionary constraints may be acting to maintain the genomic locations of CNSs and protein-coding genes in mammals to ensure proper regulation.
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Affiliation(s)
- Isaac Adeyemi Babarinde
- Department of Genetics, Graduate University for Advanced Studies, Mishima, Japan Division of Population Genetics, National Institute of Genetics, Mishima, Japan
| | - Naruya Saitou
- Department of Genetics, Graduate University for Advanced Studies, Mishima, Japan Division of Population Genetics, National Institute of Genetics, Mishima, Japan
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Haag T, Richter AM, Schneider MB, Jiménez AP, Dammann RH. The dual specificity phosphatase 2 gene is hypermethylated in human cancer and regulated by epigenetic mechanisms. BMC Cancer 2016; 16:49. [PMID: 26833217 PMCID: PMC4736155 DOI: 10.1186/s12885-016-2087-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 01/27/2016] [Indexed: 12/31/2022] Open
Abstract
Background Dual specificity phosphatases are a class of tumor-associated proteins involved in the negative regulation of the MAP kinase pathway. Downregulation of the dual specificity phosphatase 2 (DUSP2) has been reported in cancer. Epigenetic silencing of tumor suppressor genes by abnormal promoter methylation is a frequent mechanism in oncogenesis. It has been shown that the epigenetic factor CTCF is involved in the regulation of tumor suppressor genes. Methods We analyzed the promoter hypermethylation of DUSP2 in human cancer, including primary Merkel cell carcinoma by bisulfite restriction analysis and pyrosequencing. Moreover we analyzed the impact of a DNA methyltransferase inhibitor (5-Aza-dC) and CTCF on the epigenetic regulation of DUSP2 by qRT-PCR, promoter assay, chromatin immuno-precipitation and methylation analysis. Results Here we report a significant tumor-specific hypermethylation of DUSP2 in primary Merkel cell carcinoma (p = 0.05). An increase in methylation of DUSP2 was also found in 17 out of 24 (71 %) cancer cell lines, including skin and lung cancer. Treatment of cancer cells with 5-Aza-dC induced DUSP2 expression by its promoter demethylation, Additionally we observed that CTCF induces DUSP2 expression in cell lines that exhibit silencing of DUSP2. This reactivation was accompanied by increased CTCF binding and demethylation of the DUSP2 promoter. Conclusions Our data show that aberrant epigenetic inactivation of DUSP2 occurs in carcinogenesis and that CTCF is involved in the epigenetic regulation of DUSP2 expression. Electronic supplementary material The online version of this article (doi:10.1186/s12885-016-2087-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tanja Haag
- Institute for Genetics, Justus-Liebig-University, Heinrich-Buff-Ring 58-62, D-35392, Giessen, Germany.
| | - Antje M Richter
- Institute for Genetics, Justus-Liebig-University, Heinrich-Buff-Ring 58-62, D-35392, Giessen, Germany.
| | - Martin B Schneider
- Institute for Genetics, Justus-Liebig-University, Heinrich-Buff-Ring 58-62, D-35392, Giessen, Germany.
| | - Adriana P Jiménez
- Institute for Genetics, Justus-Liebig-University, Heinrich-Buff-Ring 58-62, D-35392, Giessen, Germany.
| | - Reinhard H Dammann
- Institute for Genetics, Justus-Liebig-University, Heinrich-Buff-Ring 58-62, D-35392, Giessen, Germany. .,Universities of Giessen and Marburg Lung Center, 35392, Giessen, Germany.
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Zolotarev NA, Kyrchanova OV, Maksimenko OG, Georgiev PG. Recruiting insulator protein ZIPIC of Drosophila melanogaster to minor binding sites in vivo depends on other DNA-binding transcription factors. Mol Biol 2015. [DOI: 10.1134/s0026893315060242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Dubois-Chevalier J, Staels B, Lefebvre P, Eeckhoute J. The ubiquitous transcription factor CTCF promotes lineage-specific epigenomic remodeling and establishment of transcriptional networks driving cell differentiation. Nucleus 2015; 6:15-8. [PMID: 25565413 DOI: 10.1080/19491034.2015.1004258] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Cell differentiation relies on tissue-specific transcription factors (TFs) that cooperate to establish unique transcriptomes and phenotypes. However, the role of ubiquitous TFs in these processes remains poorly defined. Recently, we have shown that the CCCTC-binding factor (CTCF) is required for adipocyte differentiation through epigenomic remodelling of adipose tissue-specific enhancers and transcriptional activation of Peroxisome proliferator-activated receptor gamma (PPARG), the main driver of the adipogenic program (PPARG), and its target genes. Here, we discuss how these findings, together with the recent literature, illuminate a functional role for ubiquitous TFs in lineage-determining transcriptional networks.
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Key Words
- 5hmC, 5-hydroxymethylcytosine
- 5mC, 5-methylcytosine
- CCCTC-binding factor (CTCF)
- CEBP, CCAAT/enhancer binding protein
- CTCF, CCCTC-binding factor
- DNA hydroxymethylation
- H3K27ac, acetylation of histone H3 lysine 27
- H3K4me1, monomethylation of histone H3 lysine 4
- KLF, Krüppel-like factors
- PPARG, Peroxisome proliferator-activated receptor gamma
- TET methylcytosine dioxygenase
- TET, Ten-eleven translocation methylcytosine dioxygenase
- TF, Transcription factor
- cell differentiation
- cistrome
- enhancer
- epigenome
- transcriptome
- ubiquitous transcription factor
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Occupancy of RNA Polymerase II Phosphorylated on Serine 5 (RNAP S5P) and RNAP S2P on Varicella-Zoster Virus Genes 9, 51, and 66 Is Independent of Transcript Abundance and Polymerase Location within the Gene. J Virol 2015; 90:1231-43. [PMID: 26559844 DOI: 10.1128/jvi.02617-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 11/05/2015] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED Regulation of gene transcription in varicella-zoster virus (VZV), a ubiquitous human neurotropic alphaherpesvirus, requires coordinated binding of multiple host and virus proteins onto specific regions of the virus genome. Chromatin immunoprecipitation (ChIP) is widely used to determine the location of specific proteins along a genomic region. Since the size range of sheared virus DNA fragments governs the limit of accurate protein localization, particularly for compact herpesvirus genomes, we used a quantitative PCR (qPCR)-based assay to determine the efficiency of VZV DNA shearing before ChIP, after which the assay was used to determine the relationship between transcript abundance and the occupancy of phosphorylated RNA polymerase II (RNAP) on the gene promoter, body, and terminus of VZV genes 9, 51, and 66. The abundance of VZV gene 9, 51, and 66 transcripts in VZV-infected human fetal lung fibroblasts was determined by reverse transcription-linked quantitative PCR. Our results showed that the C-terminal domain of RNAP is hyperphosphorylated at serine 5 (S5(P)) on VZV genes 9, 51, and 66 independently of transcript abundance and the location within the virus gene at both 1 and 3 days postinfection (dpi). In contrast, phosphorylated serine 2 (S2(P))-modified RNAP was not detected at any virus gene location at 3 dpi and was detected at levels only slightly above background levels at 1 dpi. IMPORTANCE Regulation of herpesvirus gene transcription is an elaborate choreography between proteins and DNA that is revealed by chromatin immunoprecipitation (ChIP). We used a quantitative PCR-based assay to determine fragment size after DNA shearing, a critical parameter in ChIP assays, and exposed a basic difference in the mechanism of transcription between mammalian cells and VZV. We found that hyperphosphorylation at serine 5 of the C-terminal domain of RNAP along the lengths of VZV genes (the promoter, body, and transcription termination site) was independent of mRNA abundance. In contrast, little to no enrichment of serine 3 phosphorylation of RNAP was detected at these virus gene regions. This is distinct from the findings for RNAP at highly regulated host genes, where RNAP S5(P) occupancy decreased and S2(P) levels increased as the polymerase transited through the gene. Overall, these results suggest that RNAP associates with human and virus transcriptional units through different mechanisms.
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Functional Requirements for Fab-7 Boundary Activity in the Bithorax Complex. Mol Cell Biol 2015; 35:3739-52. [PMID: 26303531 DOI: 10.1128/mcb.00456-15] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/17/2015] [Indexed: 12/23/2022] Open
Abstract
Chromatin boundaries are architectural elements that determine the three-dimensional folding of the chromatin fiber and organize the chromosome into independent units of genetic activity. The Fab-7 boundary from the Drosophila bithorax complex (BX-C) is required for the parasegment-specific expression of the Abd-B gene. We have used a replacement strategy to identify sequences that are necessary and sufficient for Fab-7 boundary function in the BX-C. Fab-7 boundary activity is known to depend on factors that are stage specific, and we describe a novel ∼700-kDa complex, the late boundary complex (LBC), that binds to Fab-7 sequences that have insulator functions in late embryos and adults. We show that the LBC is enriched in nuclear extracts from late, but not early, embryos and that it contains three insulator proteins, GAF, Mod(mdg4), and E(y)2. Its DNA binding properties are unusual in that it requires a minimal sequence of >65 bp; however, other than a GAGA motif, the three Fab-7 LBC recognition elements display few sequence similarities. Finally, we show that mutations which abrogate LBC binding in vitro inactivate the Fab-7 boundary in the BX-C.
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Functional role of dimerization and CP190 interacting domains of CTCF protein in Drosophila melanogaster. BMC Biol 2015; 13:63. [PMID: 26248466 PMCID: PMC4528719 DOI: 10.1186/s12915-015-0168-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 07/15/2015] [Indexed: 12/22/2022] Open
Abstract
Background Insulators play a central role in gene regulation, chromosomal architecture and genome function in higher eukaryotes. To learn more about how insulators carry out their diverse functions, we have begun an analysis of the Drosophila CTCF (dCTCF). CTCF is one of the few insulator proteins known to be conserved from flies to man. Results In the studies reported here we have focused on the identification and characterization of two dCTCF protein interaction modules. The first mediates dCTCF multimerization, while the second mediates dCTCF–CP190 interactions. The multimerization domain maps in the N-terminus of the dCTCF protein and likely mediates the formation of tetrameric complexes. The CP190 interaction module encompasses a sequence ~200 amino acids long that spans the C-terminal and mediates interactions with the N-terminal BTB domain of the CP190 protein. Transgene rescue experiments showed that a dCTCF protein lacking sequences critical for CP190 interactions was almost as effective as wild type in rescuing the phenotypic effects of a dCTCF null allele. The mutation did, however, affect CP190 recruitment to specific Drosophila insulator elements and had a modest effect on dCTCF chromatin association. A protein lacking the N-terminal dCTCF multimerization domain incompletely rescued the zygotic and maternal effect lethality of the null and did not rescue the defects in Abd-B regulation evident in surviving adult dCTCF mutant flies. Finally, we show that elimination of maternally contributed dCTCF at the onset of embryogenesis has quite different effects on development and Abd-B regulation than is observed when the homozygous mutant animals develop in the presence of maternally derived dCTCF activity. Conclusions Our results indicate that dCTCF–CP190 interactions are less critical for the in vivo functions of the dCTCF protein than the N-terminal dCTCF–dCTCF interaction domain. We also show that the phenotypic consequences of dCTCF mutations differ depending upon when and how dCTCF activity is lost. Electronic supplementary material The online version of this article (doi:10.1186/s12915-015-0168-7) contains supplementary material, which is available to authorized users.
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Srivastava S, Dhawan J, Mishra RK. Epigenetic mechanisms and boundaries in the regulation of mammalian Hox clusters. Mech Dev 2015; 138 Pt 2:160-169. [PMID: 26254900 DOI: 10.1016/j.mod.2015.07.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 07/29/2015] [Accepted: 07/30/2015] [Indexed: 01/07/2023]
Abstract
Hox gene expression imparts segment identity to body structures along the anterior-posterior axis and is tightly governed by higher order chromatin mechanisms. Chromatin regulatory features of the homeotic complex are best defined in Drosophila melanogaster, where multiple cis-regulatory elements have been identified that ensure collinear Hox gene expression patterns in accordance with their genomic organization. Recent studies focused on delineating the epigenetic features of the vertebrate Hox clusters have helped reveal their dynamic chromatin organization and its impact on gene expression. Enrichment for the 'activating' H3K4me3 and 'repressive' H3K27me3 histone modifications is a particularly strong read-out for transcriptional status and correlates well with the evidence for chromatin loop domain structures and stage specific topological changes at these loci. However, it is not clear how such distinct domains are imposed and regulated independent of each other. Comparative analysis of the chromatin structure and organization of the homeotic gene clusters in fly and mammals is increasingly revealing the functional conservation of chromatin mediated mechanisms. Here we discuss the case for interspersed boundary elements existing within mammalian Hox clusters along with their possible roles and mechanisms of action. Recent studies suggest a role for factors other than the well characterized vertebrate boundary factor CTCF, such as the GAGA binding factor (GAF), in maintaining chromatin domains at the Hox loci. We also present data demonstrating how such regulatory elements may be involved in organizing higher order structure and demarcating active domains of gene expression at the mammalian Hox clusters.
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Affiliation(s)
- Surabhi Srivastava
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India.
| | - Jyotsna Dhawan
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
| | - Rakesh K Mishra
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
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Kim S, Yu NK, Kaang BK. CTCF as a multifunctional protein in genome regulation and gene expression. Exp Mol Med 2015; 47:e166. [PMID: 26045254 PMCID: PMC4491725 DOI: 10.1038/emm.2015.33] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/08/2015] [Accepted: 02/27/2015] [Indexed: 12/18/2022] Open
Abstract
CCCTC-binding factor (CTCF) is a highly conserved zinc finger protein and is best known as a transcription factor. It can function as a transcriptional activator, a repressor or an insulator protein, blocking the communication between enhancers and promoters. CTCF can also recruit other transcription factors while bound to chromatin domain boundaries. The three-dimensional organization of the eukaryotic genome dictates its function, and CTCF serves as one of the core architectural proteins that help establish this organization. The mapping of CTCF-binding sites in diverse species has revealed that the genome is covered with CTCF-binding sites. Here we briefly describe the diverse roles of CTCF that contribute to genome organization and gene expression.
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Affiliation(s)
- Somi Kim
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea
| | - Nam-Kyung Yu
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea
| | - Bong-Kiun Kaang
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea
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Zhang X, Kiang KM, Zhang GP, Leung GK. Long Non-Coding RNAs Dysregulation and Function in Glioblastoma Stem Cells. Noncoding RNA 2015; 1:69-86. [PMID: 29861416 PMCID: PMC5932540 DOI: 10.3390/ncrna1010069] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 05/28/2015] [Indexed: 12/15/2022] Open
Abstract
Glioblastoma multiforme (GBM), the most common form of primary brain tumor, is highly resistant to current treatment paradigms and has a high rate of recurrence. Recent advances in the field of tumor-initiating cells suggest that glioblastoma stem cells (GSCs) may be responsible for GBM's rapid progression, treatment resistance, tumor recurrence and ultimately poor clinical prognosis. Understanding the biologically significant pathways that mediate GSC-specific characteristics offers promises in the development of novel biomarkers and therapeutics. Long non-coding RNAs (lncRNAs) have been increasingly implicated in the regulation of cancer cell biological behavior through various mechanisms. Initial studies strongly suggested that lncRNA expressions are highly dysregulated in GSCs and may play important roles in determining malignant phenotypes in GBM. Here, we review available evidence on aberrantly expressed lncRNAs identified by high throughput microarray profiling studies in GSCs. We also explore the potential functional pathways by analyzing their interactive proteins and miRNAs, with a view to shed lights on how this novel class of molecular candidates may mediate GSC maintenance and differentiation.
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Affiliation(s)
- Xiaoqin Zhang
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
| | - Karrie Meiyee Kiang
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
| | - Grace Pingde Zhang
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
| | - Gilberto Kakit Leung
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
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Kyrchanova OV, Georgiev PG. The bithorax complex of Drosophila melanogaster as a model for studying specific long-distance interactions between enhancers and promoters. RUSS J GENET+ 2015. [DOI: 10.1134/s1022795415050038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Fresán U, Cuartero S, O'Connor MB, Espinàs ML. The insulator protein CTCF regulates Drosophila steroidogenesis. Biol Open 2015; 4:852-7. [PMID: 25979705 PMCID: PMC4571099 DOI: 10.1242/bio.012344] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The steroid hormone ecdysone is a central regulator of insect development. In this report we show that CTCF expression in the prothoracic gland is required for full transcriptional activation of the Halloween genes spookier, shadow and noppera-bo, which encode ecdysone biosynthetic enzymes, and for proper timing of ecdysone-responsive gene expression. Loss of CTCF results in delayed and less synchronized larval development that can only be rescued by feeding larvae with both, the steroid hormone 20-hydroxyecdysone and cholesterol. Moreover, CTCF-knockdown in prothoracic gland cells leads to increased lipid accumulation. In conclusion, the insulator protein CTCF is required for Halloween gene expression and cholesterol homeostasis in ecdysone-producing cells controlling steroidogenesis.
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Affiliation(s)
- Ujué Fresán
- Institute of Molecular Biology of Barcelona, IBMB-CSIC, and Institute for Research in Biomedicine IRB, Barcelona 08028, Spain
| | - Sergi Cuartero
- Institute of Molecular Biology of Barcelona, IBMB-CSIC, and Institute for Research in Biomedicine IRB, Barcelona 08028, Spain
| | - Michael B O'Connor
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - M Lluisa Espinàs
- Institute of Molecular Biology of Barcelona, IBMB-CSIC, and Institute for Research in Biomedicine IRB, Barcelona 08028, Spain Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
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Sokol M, Jessen KM, Pedersen FS. Human endogenous retroviruses sustain complex and cooperative regulation of gene-containing loci and unannotated megabase-sized regions. Retrovirology 2015; 12:32. [PMID: 25927889 PMCID: PMC4422309 DOI: 10.1186/s12977-015-0161-9] [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: 01/16/2015] [Accepted: 03/30/2015] [Indexed: 12/19/2022] Open
Abstract
Background Evidence suggests that some human endogenous retroviruses and endogenous retrovirus-like repeats (here collectively ERVs) regulate the expression of neighboring genes in normal and disease states; e.g. the human globin locus is regulated by an ERV9 that coordinates long-range gene switching during hematopoiesis and activates also intergenic transcripts. While complex transcription regulation is associated with integration of certain exogenous retroviruses, comparable regulation sustained by ERVs is less understood. Findings We analyzed ERV transcription using ERV9 consensus sequences and publically available RNA-sequencing, chromatin immunoprecipitation with sequencing (ChIP-seq) and cap analysis gene expression (CAGE) data from ENCODE. We discovered previously undescribed and advanced transcription regulation mechanisms in several human reference cell lines. We show that regulation by ERVs involves long-ranging activations including complex RNA splicing patterns, and transcription of large unannotated regions ranging in size from several hundred kb to around 1 Mb. Moreover, regulation was found to be cooperatively sustained in some loci by multiple ERVs and also non-LTR repeats. Conclusion Our analyses show that endogenous retroviruses sustain advanced transcription regulation in human cell lines, which shows similarities to complex insertional mutagenesis effects exerted by exogenous retroviruses. By exposing previously undescribed regulation effects, this study should prove useful for understanding fundamental transcription mechanisms resulting from evolutionary acquisition of retroviral sequence in the human genome. Electronic supplementary material The online version of this article (doi:10.1186/s12977-015-0161-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Martin Sokol
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, DK-8000, Denmark.
| | - Karen Margrethe Jessen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, DK-8000, Denmark.
| | - Finn Skou Pedersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, DK-8000, Denmark.
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Cao J, Luo Z, Cheng Q, Xu Q, Zhang Y, Wang F, Wu Y, Song X. Three-dimensional regulation of transcription. Protein Cell 2015; 6:241-53. [PMID: 25670626 PMCID: PMC4383755 DOI: 10.1007/s13238-015-0135-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Accepted: 01/09/2015] [Indexed: 12/20/2022] Open
Abstract
Cells can adapt to environment and development by reconstructing their transcriptional networks to regulate diverse cellular processes without altering the underlying DNA sequences. These alterations, namely epigenetic changes, occur during cell division, differentiation and cell death. Numerous evidences demonstrate that epigenetic changes are governed by various types of determinants, including DNA methylation patterns, histone posttranslational modification signatures, histone variants, chromatin remodeling, and recently discovered chromosome conformation characteristics and non-coding RNAs (ncRNAs). Here, we highlight recent efforts on how the two latter epigenetic factors participate in the sophisticated transcriptional process and describe emerging techniques which permit us to uncover and gain insights into the fascinating genomic regulation.
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Affiliation(s)
- Jun Cao
- CAS Key Laboratory of Brain Function and Disease and School of Life Sciences, University of Science and Technology of China, Hefei, 230027 China
| | - Zhengyu Luo
- CAS Key Laboratory of Brain Function and Disease and School of Life Sciences, University of Science and Technology of China, Hefei, 230027 China
| | - Qingyu Cheng
- CAS Key Laboratory of Brain Function and Disease and School of Life Sciences, University of Science and Technology of China, Hefei, 230027 China
| | - Qianlan Xu
- CAS Key Laboratory of Brain Function and Disease and School of Life Sciences, University of Science and Technology of China, Hefei, 230027 China
| | - Yan Zhang
- CAS Key Laboratory of Brain Function and Disease and School of Life Sciences, University of Science and Technology of China, Hefei, 230027 China
| | - Fei Wang
- CAS Key Laboratory of Brain Function and Disease and School of Life Sciences, University of Science and Technology of China, Hefei, 230027 China
| | - Yan Wu
- CAS Key Laboratory of Brain Function and Disease and School of Life Sciences, University of Science and Technology of China, Hefei, 230027 China
| | - Xiaoyuan Song
- CAS Key Laboratory of Brain Function and Disease and School of Life Sciences, University of Science and Technology of China, Hefei, 230027 China
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Biagioli M, Ferrari F, Mendenhall EM, Zhang Y, Erdin S, Vijayvargia R, Vallabh SM, Solomos N, Manavalan P, Ragavendran A, Ozsolak F, Lee JM, Talkowski ME, Gusella JF, Macdonald ME, Park PJ, Seong IS. Htt CAG repeat expansion confers pleiotropic gains of mutant huntingtin function in chromatin regulation. Hum Mol Genet 2015; 24:2442-57. [PMID: 25574027 DOI: 10.1093/hmg/ddv006] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 01/06/2015] [Indexed: 12/15/2022] Open
Abstract
The CAG repeat expansion in the Huntington's disease gene HTT extends a polyglutamine tract in mutant huntingtin that enhances its ability to facilitate polycomb repressive complex 2 (PRC2). To gain insight into this dominant gain of function, we mapped histone modifications genome-wide across an isogenic panel of mouse embryonic stem cell (ESC) and neuronal progenitor cell (NPC) lines, comparing the effects of Htt null and different size Htt CAG mutations. We found that Htt is required in ESC for the proper deposition of histone H3K27me3 at a subset of 'bivalent' loci but in NPC it is needed at 'bivalent' loci for both the proper maintenance and the appropriate removal of this mark. In contrast, Htt CAG size, though changing histone H3K27me3, is prominently associated with altered histone H3K4me3 at 'active' loci. The sets of ESC and NPC genes with altered histone marks delineated by the lack of huntingtin or the presence of mutant huntingtin, though distinct, are enriched in similar pathways with apoptosis specifically highlighted for the CAG mutation. Thus, the manner by which huntingtin function facilitates PRC2 may afford mutant huntingtin with multiple opportunities to impinge upon the broader machinery that orchestrates developmentally appropriate chromatin status.
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Affiliation(s)
- Marta Biagioli
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA, Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | | | | | - Yijing Zhang
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Serkan Erdin
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Ravi Vijayvargia
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA, Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Sonia M Vallabh
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Nicole Solomos
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Poornima Manavalan
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Ashok Ragavendran
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Fatih Ozsolak
- RaNA Therapeutics, 790 Memorial Drive, Cambridge, MA 02139, USA
| | - Jong Min Lee
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA, Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Michael E Talkowski
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - James F Gusella
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA, Department of Genetics, Harvard Medical School, Boston, MA 02115, USA and
| | - Marcy E Macdonald
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA, Department of Neurology, Harvard Medical School, Boston, MA 02114, USA, Department of Genetics, Harvard Medical School, Boston, MA 02115, USA and
| | - Peter J Park
- Center for Biomedical Informatics, Boston, MA 02114, USA Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Ihn Sik Seong
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA, Department of Neurology, Harvard Medical School, Boston, MA 02114, USA,
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Day K, Waite LL, Thalacker-Mercer A, West A, Bamman MM, Brooks JD, Myers RM, Absher D. Differential DNA methylation with age displays both common and dynamic features across human tissues that are influenced by CpG landscape. Genome Biol 2015; 14:R102. [PMID: 24034465 PMCID: PMC4053985 DOI: 10.1186/gb-2013-14-9-r102] [Citation(s) in RCA: 242] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 08/22/2013] [Indexed: 12/30/2022] Open
Abstract
Background DNA methylation is an epigenetic modification that changes with age in human tissues, although the mechanisms and specificity of this process are still poorly understood. We compared CpG methylation changes with age across 283 human blood, brain, kidney, and skeletal muscle samples using methylation arrays to identify tissue-specific age effects. Results We found age-associated CpGs (ageCGs) that are both tissue-specific and common across tissues. Tissue-specific ageCGs are frequently located outside CpG islands with decreased methylation, and common ageCGs show the opposite trend. AgeCGs are significantly associated with poorly expressed genes, but those with decreasing methylation are linked with higher tissue-specific expression levels compared with increasing methylation. Therefore, tissue-specific gene expression may protect against common age-dependent methylation. Distinguished from other tissues, skeletal muscle ageCGs are more associated with expression, enriched near genes related to myofiber contraction, and closer to muscle-specific CTCF binding sites. Kidney-specific ageCGs are more increasingly methylated compared to other tissues as measured by affiliation with kidney-specific expressed genes. Underlying chromatin features also mark common and tissue-specific age effects reflective of poised and active chromatin states, respectively. In contrast with decreasingly methylated ageCGs, increasingly methylated ageCGs are also generally further from CTCF binding sites and enriched within lamina associated domains. Conclusions Our data identified common and tissue-specific DNA methylation changes with age that are reflective of CpG landscape and suggests both common and unique alterations within human tissues. Our findings also indicate that a simple epigenetic drift model is insufficient to explain all age-related changes in DNA methylation.
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González-Buendía E, Pérez-Molina R, Ayala-Ortega E, Guerrero G, Recillas-Targa F. Experimental strategies to manipulate the cellular levels of the multifunctional factor CTCF. Methods Mol Biol 2014; 1165:53-69. [PMID: 24839018 DOI: 10.1007/978-1-4939-0856-1_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cellular homeostasis is the result of an intricate and coordinated combinatorial of biochemical and molecular processes. Among them is the control of gene expression in the context of the chromatin structure which is central for cell survival. Interdependent action of transcription factors, cofactors, chromatin remodeling activities, and three-dimensional organization of the genome are responsible to reach exquisite levels of gene expression. Among such transcription factors there is a subset of highly specialized nuclear factors with features resembling master regulators with a large variety of functions. This is turning to be the case of the multifunctional nuclear factor CCCTC-binding protein (CTCF) which is involved in gene regulation, chromatin organization, and three-dimensional conformation of the genome inside the cell nucleus. Technically its study has turned to be challenging, in particular its posttranscriptional interference by small interference RNAs. Here we describe three main strategies to downregulate the overall abundance of CTCF in culture cell lines.
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Affiliation(s)
- Edgar González-Buendía
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-242, México, DF, 04510, México
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71
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Tan EJ, Kahata K, Idås O, Thuault S, Heldin CH, Moustakas A. The high mobility group A2 protein epigenetically silences the Cdh1 gene during epithelial-to-mesenchymal transition. Nucleic Acids Res 2014; 43:162-78. [PMID: 25492890 PMCID: PMC4288184 DOI: 10.1093/nar/gku1293] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The loss of the tumour suppressor E-cadherin (Cdh1) is a key event during tumourigenesis and epithelial-mesenchymal transition (EMT). Transforming growth factor-β (TGFβ) triggers EMT by inducing the expression of non-histone chromatin protein High Mobility Group A2 (HMGA2). We have previously shown that HMGA2, together with Smads, regulate a network of EMT-transcription factors (EMT-TFs) like Snail1, Snail2, ZEB1, ZEB2 and Twist1, most of which are well-known repressors of the Cdh1 gene. In this study, we show that the Cdh1 promoter is hypermethylated and epigenetically silenced in our constitutive EMT cell model, whereby HMGA2 is ectopically expressed in mammary epithelial NMuMG cells and these cells are highly motile and invasive. Furthermore, HMGA2 remodels the chromatin to favour binding of de novo DNA methyltransferase 3A (DNMT3A) to the Cdh1 promoter. E-cadherin expression could be restored after treatment with the DNA de-methylating agent 5-aza-2'-deoxycytidine. Here, we describe a new epigenetic role for HMGA2, which follows the actions that HMGA2 initiates via the EMT-TFs, thus achieving sustained silencing of E-cadherin expression and promoting tumour cell invasion.
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Affiliation(s)
- E-Jean Tan
- Ludwig Institute for Cancer Research, Science for Life Laboratory, Uppsala University, Uppsala SE-75124, Sweden
| | - Kaoru Kahata
- Ludwig Institute for Cancer Research, Science for Life Laboratory, Uppsala University, Uppsala SE-75124, Sweden
| | - Oskar Idås
- Ludwig Institute for Cancer Research, Science for Life Laboratory, Uppsala University, Uppsala SE-75124, Sweden
| | - Sylvie Thuault
- Ludwig Institute for Cancer Research, Science for Life Laboratory, Uppsala University, Uppsala SE-75124, Sweden
| | - Carl-Henrik Heldin
- Ludwig Institute for Cancer Research, Science for Life Laboratory, Uppsala University, Uppsala SE-75124, Sweden
| | - Aristidis Moustakas
- Ludwig Institute for Cancer Research, Science for Life Laboratory, Uppsala University, Uppsala SE-75124, Sweden Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, Uppsala SE-75123, Sweden
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72
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Roussos P, Mitchell AC, Voloudakis G, Fullard JF, Pothula VM, Tsang J, Stahl EA, Georgakopoulos A, Ruderfer DM, Charney A, Okada Y, Siminovitch KA, Worthington J, Padyukov L, Klareskog L, Gregersen PK, Plenge RM, Raychaudhuri S, Fromer M, Purcell SM, Brennand KJ, Robakis NK, Schadt EE, Akbarian S, Sklar P. A role for noncoding variation in schizophrenia. Cell Rep 2014; 9:1417-29. [PMID: 25453756 PMCID: PMC4255904 DOI: 10.1016/j.celrep.2014.10.015] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Revised: 07/31/2014] [Accepted: 10/03/2014] [Indexed: 01/20/2023] Open
Abstract
A large portion of common variant loci associated with genetic risk for schizophrenia reside within noncoding sequence of unknown function. Here, we demonstrate promoter and enhancer enrichment in schizophrenia variants associated with expression quantitative trait loci (eQTL). The enrichment is greater when functional annotations derived from the human brain are used relative to peripheral tissues. Regulatory trait concordance analysis ranked genes within schizophrenia genome-wide significant loci for a potential functional role, based on colocalization of a risk SNP, eQTL, and regulatory element sequence. We identified potential physical interactions of noncontiguous proximal and distal regulatory elements. This was verified in prefrontal cortex and -induced pluripotent stem cell-derived neurons for the L-type calcium channel (CACNA1C) risk locus. Our findings point to a functional link between schizophrenia-associated noncoding SNPs and 3D genome architecture associated with chromosomal loopings and transcriptional regulation in the brain.
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Affiliation(s)
- Panos Roussos
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; James J. Peters VA Medical Center, Mental Illness Research Education and Clinical Center (MIRECC), 130 West Kingsbridge Road, Bronx, NY 10468, USA.
| | - Amanda C Mitchell
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Georgios Voloudakis
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - John F Fullard
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Venu M Pothula
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jonathan Tsang
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Eli A Stahl
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | | | - Douglas M Ruderfer
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Alexander Charney
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yukinori Okada
- Department of Human Genetics and Disease Diversity, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 230-0045, Japan; Laboratory for Statistical Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | - Katherine A Siminovitch
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Toronto General Research Institute, Toronto, ON M5G 2M9, Canada; Department of Medicine, University of Toronto, Toronto, ON M5S 2J7, Canada
| | - Jane Worthington
- Arthritis Research UK Centre for Genetics and Genomics, Musculoskeletal Research Centre, Institute for Inflammation and Repair, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9NT, UK; National Institute for Health Research, Manchester Musculoskeletal Biomedical Research Unit, Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Sciences Centre, Manchester M13 9NT, UK
| | - Leonid Padyukov
- Rheumatology Unit, Department of Medicine (Solna), Karolinska Institutet, Stockholm 171 76, Sweden
| | - Lars Klareskog
- Rheumatology Unit, Department of Medicine (Solna), Karolinska Institutet, Stockholm 171 76, Sweden
| | - Peter K Gregersen
- The Feinstein Institute for Medical Research, North Shore-Long Island Jewish Health System, Manhasset, NY 11030, USA
| | - Robert M Plenge
- Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA 02142, USA
| | - Soumya Raychaudhuri
- Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA 02142, USA; NIHR Manchester Musculoskeletal Biomedical Research Unit, Central Manchester NHS Foundation Trust, Manchester Academic Health Sciences Centre, Manchester M13 9NT, UK
| | - Menachem Fromer
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Shaun M Purcell
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Kristen J Brennand
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Nikolaos K Robakis
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Eric E Schadt
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Schahram Akbarian
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Pamela Sklar
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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Haag T, Herkt CE, Walesch SK, Richter AM, Dammann RH. The apoptosis associated tyrosine kinase gene is frequently hypermethylated in human cancer and is regulated by epigenetic mechanisms. Genes Cancer 2014; 5:365-74. [PMID: 25352953 PMCID: PMC4209602 DOI: 10.18632/genesandcancer.28] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 08/18/2014] [Indexed: 11/25/2022] Open
Abstract
Epigenetic gene inactivation through promoter hypermethylation is an important aberration involved in the silencing of tumor-associated genes in cancer. Here we identified the apoptosis associated tyrosine kinase (AATK) as an epigenetically downregulated tumor related gene. We analyzed the epigenetic regulation of AATK in several human cancer cell lines and normal tissues by methylation and expression analysis. Hypermethylation of AATK was also analyzed in 25 primary lung tumors, 30 breast cancers and 24 matching breast tissues. In normal tissues the AATK CpG island promoter was unmethylated and AATK was expressed. Hypermethylation of AATK occurred frequently in 13 out of 14 (93%) human cancer cell lines. Methylation was reversed by 5-aza-2′-deoxycytidine treatment leading to re-expression of AATK in cancer cell lines. Aberrant methylation of AATK was also revealed in primary lung (40%) and breast (53%) cancers, but was found to be significantly less methylated in matching normal breast tissues (17%; p<0.01). In addition, we observed that AATK is epigenetically reactivated through the chromatin regulator CTCF. We further show that overexpression of Aatk significantly suppresses colony formation in cancer cell lines. Our findings suggest that the apoptosis associated tyrosine kinase is frequently inactivated in human cancers and acts as a tumor suppressive gene.
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Affiliation(s)
- Tanja Haag
- Institute for Genetics; Justus-Liebig-University; Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research; Giessen, Germany
| | - Christina E Herkt
- Institute for Genetics; Justus-Liebig-University; Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research; Giessen, Germany
| | - Sara K Walesch
- Institute for Genetics; Justus-Liebig-University; Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research; Giessen, Germany
| | - Antje M Richter
- Institute for Genetics; Justus-Liebig-University; Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research; Giessen, Germany
| | - Reinhard H Dammann
- Institute for Genetics; Justus-Liebig-University; Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research; Giessen, Germany
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Weth O, Paprotka C, Günther K, Schulte A, Baierl M, Leers J, Galjart N, Renkawitz R. CTCF induces histone variant incorporation, erases the H3K27me3 histone mark and opens chromatin. Nucleic Acids Res 2014; 42:11941-51. [PMID: 25294833 PMCID: PMC4231773 DOI: 10.1093/nar/gku937] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 09/22/2014] [Accepted: 09/24/2014] [Indexed: 12/21/2022] Open
Abstract
Insulators functionally separate active chromatin domains from inactive ones. The insulator factor, CTCF, has been found to bind to boundaries and to mediate insulator function. CTCF binding sites are depleted for the histone modification H3K27me3 and are enriched for the histone variant H3.3. In order to determine whether demethylation of H3K27me3 and H3.3 incorporation are a requirement for CTCF binding at domain boundaries or whether CTCF causes these changes, we made use of the LacI DNA binding domain to control CTCF binding by the Lac inducer IPTG. Here we show that, in contrast to the related factor CTCFL, the N-terminus plus zinc finger domain of CTCF is sufficient to open compact chromatin rapidly. This is preceded by incorporation of the histone variant H3.3, which thereby removes the H3K27me3 mark. This demonstrates the causal role for CTCF in generating the chromatin features found at insulators. Thereby, spreading of a histone modification from one domain through the insulator into the neighbouring domain is inhibited.
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Affiliation(s)
- Oliver Weth
- Institute for Genetics, Justus-Liebig-University, 35392 Giessen, Germany
| | - Christine Paprotka
- Institute for Genetics, Justus-Liebig-University, 35392 Giessen, Germany
| | - Katharina Günther
- Institute for Genetics, Justus-Liebig-University, 35392 Giessen, Germany
| | - Astrid Schulte
- Institute for Genetics, Justus-Liebig-University, 35392 Giessen, Germany
| | - Manuel Baierl
- Institute for Genetics, Justus-Liebig-University, 35392 Giessen, Germany
| | - Joerg Leers
- Institute for Genetics, Justus-Liebig-University, 35392 Giessen, Germany
| | - Niels Galjart
- Department of Cell Biology and Genetics, Erasmus MC, 3000 CA Rotterdam, The Netherlands
| | - Rainer Renkawitz
- Institute for Genetics, Justus-Liebig-University, 35392 Giessen, Germany
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75
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Maksimenko O, Bartkuhn M, Stakhov V, Herold M, Zolotarev N, Jox T, Buxa MK, Kirsch R, Bonchuk A, Fedotova A, Kyrchanova O, Renkawitz R, Georgiev P. Two new insulator proteins, Pita and ZIPIC, target CP190 to chromatin. Genome Res 2014; 25:89-99. [PMID: 25342723 PMCID: PMC4317163 DOI: 10.1101/gr.174169.114] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Insulators are multiprotein-DNA complexes that regulate the nuclear architecture. The Drosophila CP190 protein is a cofactor for the DNA-binding insulator proteins Su(Hw), CTCF, and BEAF-32. The fact that CP190 has been found at genomic sites devoid of either of the known insulator factors has until now been unexplained. We have identified two DNA-binding zinc-finger proteins, Pita, and a new factor named ZIPIC, that interact with CP190 in vivo and in vitro at specific interaction domains. Genomic binding sites for these proteins are clustered with CP190 as well as with CTCF and BEAF-32. Model binding sites for Pita or ZIPIC demonstrate a partial enhancer-blocking activity and protect gene expression from PRE-mediated silencing. The function of the CTCF-bound MCP insulator sequence requires binding of Pita. These results identify two new insulator proteins and emphasize the unifying function of CP190, which can be recruited by many DNA-binding insulator proteins.
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Affiliation(s)
- Oksana Maksimenko
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Marek Bartkuhn
- Institute for Genetics, Justus-Liebig-University Giessen, Heinrich-Buff-Ring, D-35392 Giessen, Germany
| | - Viacheslav Stakhov
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Martin Herold
- Institute for Genetics, Justus-Liebig-University Giessen, Heinrich-Buff-Ring, D-35392 Giessen, Germany
| | - Nickolay Zolotarev
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Theresa Jox
- Institute for Genetics, Justus-Liebig-University Giessen, Heinrich-Buff-Ring, D-35392 Giessen, Germany
| | - Melanie K Buxa
- Institute for Genetics, Justus-Liebig-University Giessen, Heinrich-Buff-Ring, D-35392 Giessen, Germany
| | - Ramona Kirsch
- Institute for Genetics, Justus-Liebig-University Giessen, Heinrich-Buff-Ring, D-35392 Giessen, Germany
| | - Artem Bonchuk
- Group of Transcriptional Regulation, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Anna Fedotova
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Olga Kyrchanova
- Group of Transcriptional Regulation, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Rainer Renkawitz
- Institute for Genetics, Justus-Liebig-University Giessen, Heinrich-Buff-Ring, D-35392 Giessen, Germany;
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
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76
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Alberti L, Renaud S, Losi L, Leyvraz S, Benhattar J. High expression of hTERT and stemness genes in BORIS/CTCFL positive cells isolated from embryonic cancer cells. PLoS One 2014; 9:e109921. [PMID: 25279549 PMCID: PMC4184884 DOI: 10.1371/journal.pone.0109921] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 09/12/2014] [Indexed: 01/08/2023] Open
Abstract
BORIS/CTCFL is a member of cancer testis antigen family normally expressed in germ cells. In tumors, it is aberrantly expressed although its functions are not completely well-defined. To better understand the functions of BORIS in cancer, we selected the embryonic cancer cells as a model. Using a molecular beacon, which specifically targets BORIS mRNA, we demonstrated that BORIS positive cells are a small subpopulation of tumor cells (3–5% of total). The BORIS-positive cells isolated using BORIS-molecular beacon, expressed higher telomerase hTERT, stem cell (NANOG, OCT4, SOX2) and cancer stem cell marker genes (CD44 and ALDH1) compared to the BORIS-negative tumor cells. In order to define the functional role of BORIS, stable BORIS-depleted embryonic cancer cells were generated. BORIS silencing strongly down-regulated the expression of hTERT, stem cell and cancer stem cell marker genes. Moreover, the BORIS knockdown increased cellular senescence in embryonic cancer cells, revealing a putative role of BORIS in the senescence biological program. Our data indicate an association of BORIS expressing cells subpopulation with the expression of stemness genes, highlighting the critical role played by BORIS in embryonic neoplastic disease.
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Affiliation(s)
- Loredana Alberti
- Institute of Pathology, Lausanne University Hospital, Lausanne, Switzerland
| | - Stéphanie Renaud
- Institute of Biotechnology, University of Lausanne, Lausanne, Switzerland
| | - Lorena Losi
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Serge Leyvraz
- Department of Oncology, Lausanne University Hospital, Lausanne, Switzerland
| | - Jean Benhattar
- Institute of Pathology, Lausanne University Hospital, Lausanne, Switzerland
- Biopath Lab, Lausanne, Switzerland
- * E-mail:
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77
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A functional insulator screen identifies NURF and dREAM components to be required for enhancer-blocking. PLoS One 2014; 9:e107765. [PMID: 25247414 PMCID: PMC4172637 DOI: 10.1371/journal.pone.0107765] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 08/08/2014] [Indexed: 12/27/2022] Open
Abstract
Chromatin insulators of higher eukaryotes functionally divide the genome into active and inactive domains. Furthermore, insulators regulate enhancer/promoter communication, which is evident from the Drosophila bithorax locus in which a multitude of regulatory elements control segment specific gene activity. Centrosomal protein 190 (CP190) is targeted to insulators by CTCF or other insulator DNA-binding factors. Chromatin analyses revealed that insulators are characterized by open and nucleosome depleted regions. Here, we wanted to identify chromatin modification and remodelling factors required for an enhancer blocking function. We used the well-studied Fab-8 insulator of the bithorax locus to apply a genome-wide RNAi screen for factors that contribute to the enhancer blocking function of CTCF and CP190. Among 78 genes required for optimal Fab-8 mediated enhancer blocking, all four components of the NURF complex as well as several subunits of the dREAM complex were most evident. Mass spectrometric analyses of CTCF or CP190 bound proteins as well as immune precipitation confirmed NURF and dREAM binding. Both co-localise with most CP190 binding sites in the genome and chromatin immune precipitation showed that CP190 recruits NURF and dREAM. Nucleosome occupancy and histone H3 binding analyses revealed that CP190 mediated NURF binding results in nucleosomal depletion at CP190 binding sites. Thus, we conclude that CP190 binding to CTCF or to other DNA binding insulator factors mediates recruitment of NURF and dREAM. Furthermore, the enhancer blocking function of insulators is associated with nucleosomal depletion and requires NURF and dREAM.
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78
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Dubois-Chevalier J, Oger F, Dehondt H, Firmin FF, Gheeraert C, Staels B, Lefebvre P, Eeckhoute J. A dynamic CTCF chromatin binding landscape promotes DNA hydroxymethylation and transcriptional induction of adipocyte differentiation. Nucleic Acids Res 2014; 42:10943-59. [PMID: 25183525 PMCID: PMC4176165 DOI: 10.1093/nar/gku780] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
CCCTC-binding factor (CTCF) is a ubiquitously expressed multifunctional transcription factor characterized by chromatin binding patterns often described as largely invariant. In this context, how CTCF chromatin recruitment and functionalities are used to promote cell type-specific gene expression remains poorly defined. Here, we show that, in addition to constitutively bound CTCF binding sites (CTS), the CTCF cistrome comprises a large proportion of sites showing highly dynamic binding patterns during the course of adipogenesis. Interestingly, dynamic CTCF chromatin binding is positively linked with changes in expression of genes involved in biological functions defining the different stages of adipogenesis. Importantly, a subset of these dynamic CTS are gained at cell type-specific regulatory regions, in line with a requirement for CTCF in transcriptional induction of adipocyte differentiation. This relates to, at least in part, CTCF requirement for transcriptional activation of both the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARG) and its target genes. Functionally, we show that CTCF interacts with TET methylcytosine dioxygenase (TET) enzymes and promotes adipogenic transcriptional enhancer DNA hydroxymethylation. Our study reveals a dynamic CTCF chromatin binding landscape required for epigenomic remodeling of enhancers and transcriptional activation driving cell differentiation.
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Affiliation(s)
- Julie Dubois-Chevalier
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - Frédérik Oger
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - Hélène Dehondt
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - François F Firmin
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - Céline Gheeraert
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - Bart Staels
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - Philippe Lefebvre
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - Jérôme Eeckhoute
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
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79
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Abstract
Although it was originally believed that enhancers activate only the nearest promoter, recent global analyses enabled by high-throughput technology suggest that the network of enhancer-promoter interactions is far more complex. The mechanisms that determine the specificity of enhancer-promoter interactions are still poorly understood, but they are thought to include biochemical compatibility, constraints imposed by the three-dimensional architecture of chromosomes, insulator elements, and possibly the effects of local chromatin composition. In this review, we assess the current insights into these determinants, and highlight the functional genomic approaches that will lead the way towards better mechanistic understanding.
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80
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van Arensbergen J, van Steensel B, Bussemaker HJ. In search of the determinants of enhancer-promoter interaction specificity. Trends Cell Biol 2014; 24:695-702. [PMID: 25160912 DOI: 10.1016/j.tcb.2014.07.004] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 07/15/2014] [Accepted: 07/21/2014] [Indexed: 02/07/2023]
Abstract
Although it was originally believed that enhancers activate only the nearest promoter, recent global analyses enabled by high-throughput technology suggest that the network of enhancer-promoter interactions is far more complex. The mechanisms that determine the specificity of enhancer-promoter interactions are still poorly understood, but they are thought to include biochemical compatibility, constraints imposed by the three-dimensional architecture of chromosomes, insulator elements, and possibly the effects of local chromatin composition. In this review, we assess the current insights into these determinants, and highlight the functional genomic approaches that will lead the way towards better mechanistic understanding.
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Affiliation(s)
- Joris van Arensbergen
- Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Bas van Steensel
- Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands.
| | - Harmen J Bussemaker
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; Center for Computational Biology and Bioinformatics, Columbia University, New York, NY 10032, USA.
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81
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Maksimenko O, Kyrchanova O, Bonchuk A, Stakhov V, Parshikov A, Georgiev P. Highly conserved ENY2/Sus1 protein binds to Drosophila CTCF and is required for barrier activity. Epigenetics 2014; 9:1261-70. [PMID: 25147918 DOI: 10.4161/epi.32086] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Chromatin insulators affect interactions between promoters and enhancers/silencers and function as barriers for the spreading of repressive chromatin. Drosophila insulator protein dCTCF marks active promoters and boundaries of many histone H3K27 trimethylation domains associated with repressed chromatin. In particular, dCTCF binds to such boundaries between the parasegment-specific regulatory domains of the Bithorax complex. Here we demonstrate that the evolutionarily conserved protein ENY2 is recruited to the zinc-finger domain of dCTCF and is required for the barrier activity of dCTCF-dependent insulators in transgenic lines. Inactivation of ENY2 by RNAi in BG3 cells leads to the spreading of H3K27 trimethylation and Pc protein at several dCTCF boundaries. The results suggest that evolutionarily conserved ENY2 is responsible for barrier activity mediated by the dCTCF protein.
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Affiliation(s)
- Oksana Maksimenko
- Laboratory of Gene Expression Regulation in Development; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Olga Kyrchanova
- Group of Transcriptional Regulation; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Artem Bonchuk
- Group of Transcriptional Regulation; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Viacheslav Stakhov
- Laboratory of Gene Expression Regulation in Development; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Alexander Parshikov
- Department of the Control of Genetic Processes; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
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82
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Jairam S, Edenberg HJ. An enhancer-blocking element regulates the cell-specific expression of alcohol dehydrogenase 7. Gene 2014; 547:239-44. [PMID: 24971505 DOI: 10.1016/j.gene.2014.06.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 05/02/2014] [Accepted: 06/23/2014] [Indexed: 12/14/2022]
Abstract
The class IV alcohol dehydrogenase gene ADH7 encodes an enzyme that is involved in ethanol and retinol metabolism. ADH7 is expressed mainly in the upper gastrointestinal tract and not in the liver, the major site of expression of the other closely related ADHs. We identified an intergenic sequence (iA1C), located between ADH7 and ADH1C, that has enhancer-blocking activity in liver-derived HepG2 cells that do not express their endogenous ADH7. This enhancer blocking function was cell- and position-dependent, with no activity seen in CP-A esophageal cells that express ADH7 endogenously. iA1C function was not specific to the ADH enhancers; it had a similar cell-specific effect on the SV40 enhancer. The CCCTC-binding factor (CTCF), an insulator binding protein, bound iA1C in HepG2 cells but not in CP-A cells. Our results suggest that in liver-derived cells, iA1C blocks the effects of ADH enhancers and thereby contributes to the cell specificity of ADH7 expression.
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Affiliation(s)
- Sowmya Jairam
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS4063, Indianapolis, IN 46202-5122, United States
| | - Howard J Edenberg
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS4063, Indianapolis, IN 46202-5122, United States; Department of Medical and Molecular Genetics, Indiana University School of Medicine, 635 Barnhill Drive, MS4063, Indianapolis, IN 46202-5122, United States.
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83
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CTCF binding to the first intron of the major immediate early (MIE) gene of human cytomegalovirus (HCMV) negatively regulates MIE gene expression and HCMV replication. J Virol 2014; 88:7389-401. [PMID: 24741094 DOI: 10.1128/jvi.00845-14] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
UNLABELLED Human cytomegalovirus (HCMV) gene expression during infection is highly regulated, with sequential expression of immediate-early (IE), early (E), and late (L) gene transcripts. To explore the potential role of chromatin regulatory factors that may regulate HCMV gene expression and DNA replication, we investigated the interaction of HCMV with the cellular chromatin-organizing factor CTCF. Here, we show that HCMV-infected cells produce higher levels of CTCF mRNA and protein at early stages of infection. We also show that CTCF depletion by short hairpin RNA results in an increase in major IE (MIE) and E gene expression and an about 50-fold increase in HCMV particle production. We identified a DNA sequence (TTAACGGTGGAGGGCAGTGT) in the first intron (intron A) of the MIE gene that interacts directly with CTCF. Deletion of this CTCF-binding site led to an increase in MIE gene expression in both transient-transfection and infection assays. Deletion of the CTCF-binding site in the HCMV bacterial artificial chromosome plasmid genome resulted in an about 10-fold increase in the rate of viral replication relative to either wild-type or revertant HCMV. The CTCF-binding site deletion had no detectable effect on MIE gene-splicing regulation, nor did CTCF knockdown or overexpression of CTCF alter the ratio of IE1 to IE2. Therefore, CTCF binds to DNA within the MIE gene at the position of the first intron to affect RNA polymerase II function during the early stages of viral transcription. Finally, the CTCF-binding sequence in CMV is evolutionarily conserved, as a similar sequence in murine CMV (MCMV) intron A was found to interact with CTCF and similarly function in the repression of MCMV MIE gene expression mediated by CTCF. IMPORTANCE Our findings that CTCF binds to intron A of the cytomegalovirus (CMV) major immediate-early (MIE) gene and functions to repress MIE gene expression and viral replication are highly significant. For the first time, a chromatin-organizing factor, CTCF, has been found to facilitate human CMV gene expression, which affects viral replication. We also identified a CTCF-binding motif in the first intron (also called intron A) that directly binds to CTCF and is required for CTCF to repress MIE gene expression. Finally, we show that the CTCF-binding motif is conserved in CMV because a similar DNA sequence was found in murine CMV (MCMV) that is required for CTCF to bind to MCMV MIE gene to repress MCMV MIE gene expression.
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84
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Human colorectal cancer-specific CCAT1-L lncRNA regulates long-range chromatin interactions at the MYC locus. Cell Res 2014; 24:513-31. [PMID: 24662484 PMCID: PMC4011346 DOI: 10.1038/cr.2014.35] [Citation(s) in RCA: 534] [Impact Index Per Article: 53.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 01/06/2013] [Accepted: 01/27/2012] [Indexed: 12/12/2022] Open
Abstract
The human 8q24 gene desert contains multiple enhancers that form tissue-specific long-range chromatin loops with the MYC oncogene, but how chromatin looping at the MYC locus is regulated remains poorly understood. Here we demonstrate that a long noncoding RNA (lncRNA), CCAT1-L, is transcribed specifically in human colorectal cancers from a locus 515 kb upstream of MYC. This lncRNA plays a role in MYC transcriptional regulation and promotes long-range chromatin looping. Importantly, the CCAT1-L locus is located within a strong super-enhancer and is spatially close to MYC. Knockdown of CCAT1-L reduced long-range interactions between the MYC promoter and its enhancers. In addition, CCAT1-L interacts with CTCF and modulates chromatin conformation at these loop regions. These results reveal an important role of a previously unannotated lncRNA in gene regulation at the MYC locus.
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85
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FIREWACh: high-throughput functional detection of transcriptional regulatory modules in mammalian cells. Nat Methods 2014; 11:559-65. [PMID: 24658142 PMCID: PMC4020622 DOI: 10.1038/nmeth.2885] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 01/28/2014] [Indexed: 11/08/2022]
Abstract
Promoters and enhancers establish precise gene transcription patterns. The development of functional approaches for their identification in mammalian cells has been complicated by the size of these genomes. Here we report a high-throughput functional assay for directly identifying active promoter and enhancer elements called FIREWACh (Functional Identification of Regulatory Elements Within Accessible Chromatin), which we used to simultaneously assess over 80,000 DNA fragments derived from nucleosome-free regions within the chromatin of embryonic stem cells (ESCs) and identify 6,364 active regulatory elements. Many of these represent newly discovered ESC-specific enhancers, showing enriched binding-site motifs for ESC-specific transcription factors including SOX2, POU5F1 (OCT4) and KLF4. The application of FIREWACh to additional cultured cell types will facilitate functional annotation of the genome and expand our view of transcriptional network dynamics.
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86
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Hoivik EA, Kusonmano K, Halle MK, Berg A, Wik E, Werner HMJ, Petersen K, Oyan AM, Kalland KH, Krakstad C, Trovik J, Widschwendter M, Salvesen HB. Hypomethylation of the CTCFL/BORIS promoter and aberrant expression during endometrial cancer progression suggests a role as an Epi-driver gene. Oncotarget 2014; 5:1052-61. [PMID: 24658009 PMCID: PMC4011582 DOI: 10.18632/oncotarget.1697] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 01/26/2014] [Indexed: 12/11/2022] Open
Abstract
Cancers arise through accumulating genetic and epigenetic alterations, considered relevant for phenotype and approaches to targeting new therapies. We investigated a unique collection of endometrial cancer precursor samples and clinically annotated primary and metastatic lesions for two evolutionary and functionally related transcription factors, CCCTC-binding factor (zinc finger protein) (CTCF) and its paralogue CTCF-like factor, also denoted Brother of the Regulator of Imprinted Sites (CTCFL/BORIS). CTCF, a chromatin modeling- and transcription factor, is normally expressed in a ubiquitous fashion, while CTCFL/BORIS is restricted to the testis. In cancer, CTCF is thought to be a tumor suppressor, while CTCFL/BORIS has been suggested as an oncogene. CTCF mutations were identified in 13%, with CTCF hotspot frameshift mutations at p.T204, all observed solely in the endometrioid subtype, but with no association with outcome. Interestingly, CTCFL/BORIS was amongst the top ranked genes differentially expressed between endometrioid and non-endometrioid tumors, and increasing mRNA level of CTCFL/BORIS was highly significantly associated with poor survival. As aberrant CTCFL/BORIS expression might relate to loss of methylation, we explored methylation status in clinical samples from complex atypical hyperplasia, through primary tumors to metastatic lesions, demonstrating a pattern of DNA methylation loss during disease development and progression in line with the increase in CTCFL/BORIS mRNA expression observed. Thus, CTCF and CTCFL/BORIS are found to diverge in the different subtypes of endometrial cancer, with CTCFL/BORIS activation through demethylation from precursors to metastatic lesions. We thus propose, CTCFL/BORIS as an Epi-driver gene in endometrial cancer, suggesting a potential for future vaccine development.
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Affiliation(s)
- Erling A. Hoivik
- Department of Obstetrics and Gynecology, Haukeland University Hospital, Bergen, Norway
- Centre for Cancer Biomarkers, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Kanthida Kusonmano
- Department of Obstetrics and Gynecology, Haukeland University Hospital, Bergen, Norway
- Computational Biology Unit, University of Bergen, Norway
| | - Mari K. Halle
- Department of Obstetrics and Gynecology, Haukeland University Hospital, Bergen, Norway
- Centre for Cancer Biomarkers, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Anna Berg
- Department of Obstetrics and Gynecology, Haukeland University Hospital, Bergen, Norway
- Centre for Cancer Biomarkers, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Elisabeth Wik
- Centre for Cancer Biomarkers, Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Pathology, Haukeland University Hospital, Bergen, Norway
| | - Henrica M. J. Werner
- Department of Obstetrics and Gynecology, Haukeland University Hospital, Bergen, Norway
| | - Kjell Petersen
- Computational Biology Unit, University of Bergen, Norway
| | - Anne M. Oyan
- Centre for Cancer Biomarkers, Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Microbiology, Haukeland University Hospital, Bergen, Norway
| | - Karl-Henning Kalland
- Centre for Cancer Biomarkers, Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Microbiology, Haukeland University Hospital, Bergen, Norway
| | - Camilla Krakstad
- Department of Obstetrics and Gynecology, Haukeland University Hospital, Bergen, Norway
- Centre for Cancer Biomarkers, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Jone Trovik
- Department of Obstetrics and Gynecology, Haukeland University Hospital, Bergen, Norway
- Centre for Cancer Biomarkers, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Martin Widschwendter
- Department of Women's Cancer, University College London Elizabeth Garrett Anderson Institute for Women's Health, University College London, United Kingdom
| | - Helga B. Salvesen
- Department of Obstetrics and Gynecology, Haukeland University Hospital, Bergen, Norway
- Centre for Cancer Biomarkers, Department of Clinical Science, University of Bergen, Bergen, Norway
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87
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Maksimenko O, Georgiev P. Mechanisms and proteins involved in long-distance interactions. Front Genet 2014; 5:28. [PMID: 24600469 PMCID: PMC3927085 DOI: 10.3389/fgene.2014.00028] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 01/25/2014] [Indexed: 12/28/2022] Open
Abstract
Due to advances in genome-wide technologies, consistent distant interactions within chromosomes of higher eukaryotes have been revealed. In particular, it has been shown that enhancers can specifically and directly interact with promoters by looping out intervening sequences, which can be up to several hundred kilobases long. This review is focused on transcription factors that are supposed to be involved in long-range interactions. Available data are in agreement with the model that several known transcription factors and insulator proteins belong to an abundant but poorly studied class of proteins that are responsible for chromosomal architecture.
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Affiliation(s)
- Oksana Maksimenko
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences Moscow, Russia
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88
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Chen HS, Martin KA, Lu F, Lupey LN, Mueller JM, Lieberman PM, Tempera I. Epigenetic deregulation of the LMP1/LMP2 locus of Epstein-Barr virus by mutation of a single CTCF-cohesin binding site. J Virol 2014; 88:1703-13. [PMID: 24257606 PMCID: PMC3911611 DOI: 10.1128/jvi.02209-13] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 11/12/2013] [Indexed: 01/31/2023] Open
Abstract
The chromatin regulatory factors CTCF and cohesin have been implicated in the coordinated control of multiple gene loci in Epstein-Barr virus (EBV) latency. We have found that CTCF and cohesin are highly enriched at the convergent and partially overlapping transcripts for the LMP1 and LMP2A genes, but it is not yet known how CTCF and cohesin may coordinately regulate these transcripts. We now show that genetic disruption of this CTCF binding site (EBVΔCTCF166) leads to a deregulation of LMP1, LMP2A, and LMP2B transcription in EBV-immortalized B lymphocytes. EBVΔCTCF166 virus-immortalized primary B lymphocytes showed a decrease in LMP1 and LMP2A mRNA and a corresponding increase in LMP2B mRNA. The reduction of LMP1 and LMP2A correlated with a loss of euchromatic histone modification H3K9ac and a corresponding increase in heterochromatic histone modification H3K9me3 at the LMP2A promoter region in EBVΔCTCF166. Chromosome conformation capture (3C) revealed that DNA loop formation with the origin of plasmid replication (OriP) enhancer was eliminated in EBVΔCTCF166. We also observed that the EBV episome copy number was elevated in EBVΔCTCF166 and that this was not due to increased lytic cycle activity. These findings suggest that a single CTCF binding site controls LMP2A and LMP1 promoter selection, chromatin boundary function, DNA loop formation, and episome copy number control during EBV latency.
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Affiliation(s)
| | - Kayla A. Martin
- The Fels Institute, Department of Microbiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
| | - Fang Lu
- The Wistar Institute, Philadelphia, Pennsylvania, USA
| | - Lena N. Lupey
- The Fels Institute, Department of Microbiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
| | | | | | - Italo Tempera
- The Fels Institute, Department of Microbiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
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89
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Ahanger SH, Günther K, Weth O, Bartkuhn M, Bhonde RR, Shouche YS, Renkawitz R. Ectopically tethered CP190 induces large-scale chromatin decondensation. Sci Rep 2014; 4:3917. [PMID: 24472778 PMCID: PMC3905270 DOI: 10.1038/srep03917] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 01/10/2014] [Indexed: 01/04/2023] Open
Abstract
Insulator mediated alteration in higher-order chromatin and/or nucleosome organization is an important aspect of epigenetic gene regulation. Recent studies have suggested a key role for CP190 in such processes. In this study, we analysed the effects of ectopically tethered insulator factors on chromatin structure and found that CP190 induces large-scale decondensation when targeted to a condensed lacO array in mammalian and Drosophila cells. In contrast, dCTCF alone, is unable to cause such a decondensation, however, when CP190 is present, dCTCF recruits it to the lacO array and mediates chromatin unfolding. The CP190 induced opening of chromatin may not be correlated with transcriptional activation, as binding of CP190 does not enhance luciferase activity in reporter assays. We propose that CP190 may mediate histone modification and chromatin remodelling activity to induce an open chromatin state by its direct recruitment or targeting by a DNA binding factor such as dCTCF.
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Affiliation(s)
- Sajad H Ahanger
- 1] National Centre for Cell Science, Pune 411007, India [2] Institute for Genetics, Justus-Liebig University, Giessen D-35392, Germany
| | - Katharina Günther
- Institute for Genetics, Justus-Liebig University, Giessen D-35392, Germany
| | - Oliver Weth
- Institute for Genetics, Justus-Liebig University, Giessen D-35392, Germany
| | - Marek Bartkuhn
- Institute for Genetics, Justus-Liebig University, Giessen D-35392, Germany
| | | | | | - Rainer Renkawitz
- Institute for Genetics, Justus-Liebig University, Giessen D-35392, Germany
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90
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Atkinson TJ, Halfon MS. Regulation of gene expression in the genomic context. Comput Struct Biotechnol J 2014; 9:e201401001. [PMID: 24688749 PMCID: PMC3962188 DOI: 10.5936/csbj.201401001] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 12/10/2013] [Accepted: 12/29/2013] [Indexed: 11/22/2022] Open
Abstract
Metazoan life is dependent on the proper temporal and spatial control of gene expression within the many cells-essentially all with the identical genome-that make up the organism. While much is understood about how individual gene regulatory elements function, many questions remain about how they interact to maintain correct regulation globally throughout the genome. In this review we summarize the basic features and functions of the crucial regulatory elements promoters, enhancers, and insulators and discuss some of the ways in which proper interactions between these elements is realized. We focus in particular on the role of core promoter sequences and propose explanations for some of the contradictory results seen in experiments aimed at understanding insulator function. We suggest that gene regulation depends on local genomic context and argue that more holistic in vivo investigations that take into account multiple local features will be necessary to understand how genome-wide gene regulation is maintained.
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Affiliation(s)
- Taylor J Atkinson
- Department of Biochemistry, University at Buffalo-State University of New York, Buffalo, NY 14203, USA
- NY State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY 14203, USA
| | - Marc S Halfon
- Department of Biochemistry, University at Buffalo-State University of New York, Buffalo, NY 14203, USA
- Department of Biological Sciences, University at Buffalo-State University of New York, Buffalo, NY 14203, USA
- NY State Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY 14203, USA
- Molecular and Cellular Biology Department and Program in Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
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91
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Liao BY, Chang A. Accumulation of CTCF-binding sites drives expression divergence between tandemly duplicated genes in humans. BMC Genomics 2014; 15 Suppl 1:S8. [PMID: 24564680 PMCID: PMC4046690 DOI: 10.1186/1471-2164-15-s1-s8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Background During eukaryotic genome evolution, tandem gene duplication is the most frequent event giving rise to clustered gene families. However, how expression divergence between tandemly duplicated genes has emerged and maintained remain unclear. In particular, it is unknown if epigenetic regulators have been involved in the process. Results We demonstrate that CCCTC-binding factor (CTCF), the master epigenetic regulator and the only known insulator protein in humans, has played a predominant role in generating divergence in both expression profiles and expression levels between adjacent paralogs in the human genome. This phenomenon was not observed for non-paralogous adjacent genes. After tandem duplication events, CTCF-binding sites gradually accumulate between paralogs. This trend was more prominent for genes involved in particular functions. Conclusions The accumulation of CTCF-binding sites drives expression divergence of tandemly duplicated genes. This process is likely targeted by natural selection. Our study reveals the importance of CTCF to the evolution of animal diversity and complexity. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-S1-S8) contains supplementary material, which is available to authorized users.
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92
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Weingarten-Gabbay S, Segal E. The grammar of transcriptional regulation. Hum Genet 2014; 133:701-11. [PMID: 24390306 DOI: 10.1007/s00439-013-1413-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 12/24/2013] [Indexed: 12/22/2022]
Abstract
Eukaryotes employ combinatorial strategies to generate a variety of expression patterns from a relatively small set of regulatory DNA elements. As in any other language, deciphering the mapping between DNA and expression requires an understanding of the set of rules that govern basic principles in transcriptional regulation, the functional elements involved, and the ways in which they combine to orchestrate a transcriptional output. Here, we review the current understanding of various grammatical rules, including the effect on expression of the number of transcription factor binding sites, their location, orientation, affinity and activity; co-association with different factors; and intrinsic nucleosome organization. We review different methods that are used to study the grammar of transcription regulation, highlight gaps in current understanding, and discuss how recent technological advances may be utilized to bridge them.
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Affiliation(s)
- Shira Weingarten-Gabbay
- Department of Computer Science, Applied Mathematics and Department of Molecular Cell Biology, Weizmann Institute of Science, 76100, Rehovot, Israel,
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93
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Marsman J, O'Neill AC, Kao BRY, Rhodes JM, Meier M, Antony J, Mönnich M, Horsfield JA. Cohesin and CTCF differentially regulate spatiotemporal runx1 expression during zebrafish development. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1839:50-61. [PMID: 24321385 DOI: 10.1016/j.bbagrm.2013.11.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 11/19/2013] [Accepted: 11/25/2013] [Indexed: 11/23/2022]
Abstract
Runx1 is a transcription factor essential for definitive hematopoiesis. In all vertebrates, the Runx1 gene is transcribed from two promoters: a proximal promoter (P2), and a distal promoter (P1). We previously found that runx1 expression in a specific hematopoietic cell population in zebrafish embryos depends on cohesin. Here we show that zebrafish runx1 is directly bound by cohesin and CCCTC binding factor (CTCF) at the P1 and P2 promoters, and within the intron between P1 and P2. Cohesin initiates expression of runx1 in the posterior lateral mesoderm and influences promoter use, while CTCF represses its expression in the newly emerging cells of the tail bud. The intronic binding sites for cohesin and CTCF coincide with histone modifications that confer enhancer-like properties, and two of the cohesin/CTCF sites behaved as insulators in an in vivo assay. The identified cohesin and CTCF binding sites are likely to be cis-regulatory elements (CREs) for runx1 since they also recruit RNA polymerase II (RNAPII). CTCF depletion excluded RNAPII from two intronic CREs but not the promoters of runx1. We propose that cohesin and CTCF have distinct functions in the regulation of runx1 during zebrafish embryogenesis, and that these regulatory functions are likely to involve runx1 intronic CREs. Cohesin (but not CTCF) depletion enhanced RUNX1 expression in a human leukemia cell line, suggesting conservation of RUNX1 regulation through evolution.
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Affiliation(s)
- Judith Marsman
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Adam C O'Neill
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Betty Rui-Yun Kao
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Jenny M Rhodes
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Michael Meier
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Jisha Antony
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Maren Mönnich
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand
| | - Julia A Horsfield
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin, New Zealand.
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94
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Batlle-López A, Cortiguera MG, Rosa-Garrido M, Blanco R, del Cerro E, Torrano V, Wagner SD, Delgado MD. Novel CTCF binding at a site in exon1A of BCL6 is associated with active histone marks and a transcriptionally active locus. Oncogene 2013; 34:246-56. [PMID: 24362533 DOI: 10.1038/onc.2013.535] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 10/01/2013] [Accepted: 11/01/2013] [Indexed: 12/14/2022]
Abstract
BCL6 is a zinc-finger transcriptional repressor, which is highly expressed in germinal centre B-cells and is essential for germinal centre formation and T-dependent antibody responses. Constitutive BCL6 expression is sufficient to produce lymphomas in mice. Deregulated expression of BCL6 due to chromosomal rearrangements, mutations of a negative autoregulatory site in the BCL6 promoter region and aberrant post-translational modifications have been detected in a number of human lymphomas. Tight lineage and temporal regulation of BCL6 is, therefore, required for normal immunity, and abnormal regulation occurs in lymphomas. CCCTC-binding factor (CTCF) is a multi-functional chromatin regulator, which has recently been shown to bind in a methylation-sensitive manner to sites within the BCL6 first intron. We demonstrate a novel CTCF-binding site in BCL6 exon1A within a potential CpG island, which is unmethylated both in cell lines and in primary lymphoma samples. CTCF binding, which was found in BCL6-expressing cell lines, correlated with the presence of histone variant H2A.Z and active histone marks, suggesting that CTCF induces chromatin modification at a transcriptionally active BCL6 locus. CTCF binding to exon1A was required to maintain BCL6 expression in germinal centre cells by avoiding BCL6-negative autoregulation. Silencing of CTCF in BCL6-expressing cells reduced BCL6 mRNA and protein expression, which is sufficient to induce B-cell terminal differentiation toward plasma cells. Moreover, lack of CTCF binding to exon1A shifts the BCL6 local chromatin from an active to a repressive state. This work demonstrates that, in contexts in which BCL6 is expressed, CTCF binding to BCL6 exon1A associates with epigenetic modifications indicative of transcriptionally open chromatin.
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Affiliation(s)
- A Batlle-López
- 1] Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC) and Departamento de Biología Molecular, Universidad de Cantabria, CSIC, SODERCAN, Santander, Spain [2] Servicio de Hematología, Hospital U. Marqués de Valdecilla, and IFIMAV-FMV, Santander, Spain
| | - M G Cortiguera
- 1] Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC) and Departamento de Biología Molecular, Universidad de Cantabria, CSIC, SODERCAN, Santander, Spain [2] Servicio de Hematología, Hospital U. Marqués de Valdecilla, and IFIMAV-FMV, Santander, Spain
| | - M Rosa-Garrido
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC) and Departamento de Biología Molecular, Universidad de Cantabria, CSIC, SODERCAN, Santander, Spain
| | - R Blanco
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC) and Departamento de Biología Molecular, Universidad de Cantabria, CSIC, SODERCAN, Santander, Spain
| | - E del Cerro
- Servicio de Hematología, Hospital U. Marqués de Valdecilla, and IFIMAV-FMV, Santander, Spain
| | - V Torrano
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC) and Departamento de Biología Molecular, Universidad de Cantabria, CSIC, SODERCAN, Santander, Spain
| | - S D Wagner
- Department of Cancer Studies and Molecular Medicine and MRC Toxicology Unit, University of Leicester, Leicester, UK
| | - M D Delgado
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC) and Departamento de Biología Molecular, Universidad de Cantabria, CSIC, SODERCAN, Santander, Spain
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95
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Damaschke NA, Yang B, Bhusari S, Svaren JP, Jarrard D. Epigenetic susceptibility factors for prostate cancer with aging. Prostate 2013; 73:1721-30. [PMID: 23999928 PMCID: PMC4237278 DOI: 10.1002/pros.22716] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 07/06/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND Increasing age is a significant risk factor for prostate cancer. The prostate is exposed to environmental and endogenous stress that may underlie this remarkable incidence. DNA methylation, genomic imprinting, and histone modifications are examples of epigenetic factors known to undergo change in the aging and cancerous prostate. In this review we examine the data linking epigenetic alterations in the prostate with aging to cancer development. METHODS An online search of current and past peer reviewed literature on epigenetic changes with cancer and aging was performed. Relevant articles were analyzed. RESULTS Epigenetic changes are responsible for modifying expression of oncogenes and tumor suppressors. Several of these changes may represent a field defect that predisposes to cancer development. Focal hypermethylation occurs at CpG islands in the promoters of certain genes including GSTP1, RARβ2, and RASSF1A with both age and cancer, while global hypomethylation is seen in prostate cancer and known to occur in the colon and other organs. A loss of genomic imprinting is responsible for biallelic expression of the well-known Insulin-like Growth Factor 2 (IGF2) gene. Loss of imprinting (LOI) at IGF2 has been documented in cancer and is also known to occur in benign aging prostate tissue marking the presence of cancer. Histone modifications have the ability to dictate chromatin structure and direct gene expression. CONCLUSIONS Epigenetic changes with aging represent molecular mechanisms to explain the increased susceptibly of the prostate to develop cancer in older men. These changes may provide an opportunity for diagnostic and chemopreventive strategies given the epigenome can be modified.
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Affiliation(s)
- N. A. Damaschke
- Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - B. Yang
- Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - S. Bhusari
- Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - J. P. Svaren
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, 53972
- University of Wisconsin Carbone Comprehensive Cancer Center, Madison, Wisconsin
| | - D.F. Jarrard
- Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
- University of Wisconsin Carbone Comprehensive Cancer Center, Madison, Wisconsin
- Environmental and Molecular Toxicology, University of Wisconsin, Madison, Wisconsin
- Correspondence to: D.F. Jarrard, MD, 7037 Wisconsin Institutes of Medical Research, 1111 Highland Avenue, Madison, WI 53792.
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96
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Chetverina D, Aoki T, Erokhin M, Georgiev P, Schedl P. Making connections: insulators organize eukaryotic chromosomes into independent cis-regulatory networks. Bioessays 2013; 36:163-72. [PMID: 24277632 DOI: 10.1002/bies.201300125] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Insulators play a central role in subdividing the chromosome into a series of discrete topologically independent domains and in ensuring that enhancers and silencers contact their appropriate target genes. In this review we first discuss the general characteristics of insulator elements and their associated protein factors. A growing collection of insulator proteins have been identified including a family of proteins whose expression is developmentally regulated. We next consider several unexpected discoveries that require us to completely rethink how insulators function (and how they can best be assayed). These discoveries also require a reevaluation of how insulators might restrict or orchestrate (by preventing or promoting) interactions between regulatory elements and their target genes. We conclude by connecting these new insights into the mechanisms of insulator action to dynamic changes in the three-dimensional topology of the chromatin fiber and the generation of specific patterns of gene activity during development and differentiation.
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Affiliation(s)
- Darya Chetverina
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
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97
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Itzykson R, Fenaux P. Epigenetics of myelodysplastic syndromes. Leukemia 2013; 28:497-506. [DOI: 10.1038/leu.2013.343] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 10/27/2013] [Accepted: 10/30/2013] [Indexed: 12/23/2022]
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98
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Abstract
The human gammaherpesviruses Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) establish long-term latent infections associated with diverse human cancers. Viral oncogenesis depends on the ability of the latent viral genome to persist in host nuclei as episomes that express a restricted yet dynamic pattern of viral genes. Multiple epigenetic events control viral episome generation and maintenance. This Review highlights some of the recent findings on the role of chromatin assembly, histone and DNA modifications, and higher-order chromosome structures that enable gammaherpesviruses to establish stable latent infections that mediate viral pathogenesis.
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99
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Kyrchanova O, Georgiev P. Chromatin insulators and long-distance interactions in Drosophila. FEBS Lett 2013; 588:8-14. [PMID: 24211836 DOI: 10.1016/j.febslet.2013.10.039] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 10/25/2013] [Accepted: 10/25/2013] [Indexed: 12/31/2022]
Abstract
Data on long-distance enhancer-mediated activation of gene promoters and complex regulation of gene expression by multiple enhancers have prompted the hypothesis that the action of enhancers is restricted by insulators. Studies with transgenic lines have shown that insulators are responsible for establishing proper local interactions between regulatory elements, but not for defining independent transcriptional domains that restrict the activity of enhancers. It has also become apparent that enhancer blocking is only one of several functional activities of known insulator proteins, which also contribute to the organization of chromosome architecture and the integrity of regulatory elements.
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Affiliation(s)
- Olga Kyrchanova
- Group of Transcriptional Regulation, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia.
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100
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Fujioka M, Sun G, Jaynes JB. The Drosophila eve insulator Homie promotes eve expression and protects the adjacent gene from repression by polycomb spreading. PLoS Genet 2013; 9:e1003883. [PMID: 24204298 PMCID: PMC3814318 DOI: 10.1371/journal.pgen.1003883] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 08/29/2013] [Indexed: 12/18/2022] Open
Abstract
Insulators can block the action of enhancers on promoters and the spreading of repressive chromatin, as well as facilitating specific enhancer-promoter interactions. However, recent studies have called into question whether the activities ascribed to insulators in model transgene assays actually reflect their functions in the genome. The Drosophila even skipped (eve) gene is a Polycomb (Pc) domain with a Pc-group response element (PRE) at one end, flanked by an insulator, an arrangement also seen in other genes. Here, we show that this insulator has three major functions. It blocks the spreading of the eve Pc domain, preventing repression of the adjacent gene, TER94. It prevents activation of TER94 by eve regulatory DNA. It also facilitates normal eve expression. When Homie is deleted in the context of a large transgene that mimics both eve and TER94 regulation, TER94 is repressed. This repression depends on the eve PRE. Ubiquitous TER94 expression is “replaced” by expression in an eve pattern when Homie is deleted, and this effect is reversed when the PRE is also removed. Repression of TER94 is attributable to spreading of the eve Pc domain into the TER94 locus, accompanied by an increase in histone H3 trimethylation at lysine 27. Other PREs can functionally replace the eve PRE, and other insulators can block PRE-dependent repression in this context. The full activity of the eve promoter is also dependent on Homie, and other insulators can promote normal eve enhancer-promoter communication. Our data suggest that this is not due to preventing promoter competition, but is likely the result of the insulator organizing a chromosomal conformation favorable to normal enhancer-promoter interactions. Thus, insulator activities in a native context include enhancer blocking and enhancer-promoter facilitation, as well as preventing the spread of repressive chromatin. Insulators are specialized DNA elements that can separate the genome into functional units. Most of the current thinking about these elements comes from studies done with model transgenes. Studies of insulators within the specialized Hox gene complexes have suggested that model transgenes can reflect the normal functions of these elements in their native context. However, recent genome-wide studies have called this into question. This work analyzes the native function of an insulator that resides between the Drosophila genes eve and TER94, which are expressed in very different patterns. Also, the eve gene is a Polycomb (Pc) domain, a specialized type of chromatin that is found in many places throughout the genome. We show that this insulator has three major functions. It blocks the spreading of the eve Pc domain, preventing repression of TER94. It prevents activation of TER94 by eve regulatory DNA. It also facilitates normal eve expression. Each of these activities are consistent with those seen with model transgenes, and other known insulators can provide these functions in this context. This work provides a novel and convincing example of the normal role of insulators in regulating the eukaryotic genome, as well as providing insights into their mechanisms of action.
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Affiliation(s)
- Miki Fujioka
- Department of Biochemistry and Molecular Biology and the Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Guizhi Sun
- Department of Biochemistry and Molecular Biology and the Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - James B. Jaynes
- Department of Biochemistry and Molecular Biology and the Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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