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Höglund A, Henriksen R, Churcher AM, Guerrero-Bosagna CM, Martinez-Barrio A, Johnsson M, Jensen P, Wright D. The regulation of methylation on the Z chromosome and the identification of multiple novel Male Hyper-Methylated regions in the chicken. PLoS Genet 2024; 20:e1010719. [PMID: 38457441 PMCID: PMC10954189 DOI: 10.1371/journal.pgen.1010719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 03/20/2024] [Accepted: 01/31/2024] [Indexed: 03/10/2024] Open
Abstract
DNA methylation is a key regulator of eukaryote genomes, and is of particular relevance in the regulation of gene expression on the sex chromosomes, with a key role in dosage compensation in mammalian XY systems. In the case of birds, dosage compensation is largely absent, with it being restricted to two small Male Hyper-Methylated (MHM) regions on the Z chromosome. To investigate how variation in DNA methylation is regulated on the Z chromosome we utilised a wild x domestic advanced intercross in the chicken, with both hypothalamic methylomes and transcriptomes assayed in 124 individuals. The relatively large numbers of individuals allowed us to identify additional genomic MHM regions on the Z chromosome that were significantly differentially methylated between the sexes. These regions appear to down-regulate local gene expression in males, but not remove it entirely (unlike the lncRNAs identified in the initial MHM regions). These MHM regions were further tested and the most balanced genes appear to show decreased expression in males, whilst methylation appeared to be far more correlated with gene expression in the less balanced, as compared to the most balanced genes. In addition, quantitative trait loci (QTL) that regulate variation in methylation on the Z chromosome, and those loci that regulate methylation on the autosomes that derive from the Z chromosome were mapped. Trans-effect hotspots were also identified that were based on the autosomes but affected the Z, and also one that was based on the Z chromosome but that affected both autosomal and sex chromosome DNA methylation regulation. We show that both cis and trans loci that originate from the Z chromosome never exhibit an interaction with sex, whereas trans loci originating from the autosomes but affecting the Z chromosome always display such an interaction. Our results highlight how additional MHM regions are actually present on the Z chromosome, and they appear to have smaller-scale effects on gene expression in males. Quantitative variation in methylation is also regulated both from the autosomes to the Z chromosome, and from the Z chromosome to the autosomes.
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Affiliation(s)
- Andrey Höglund
- Science for Life Laboratory, Department of Environmental Science, Stockholm University, Stockholm, Sweden
| | - Rie Henriksen
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
| | | | - Carlos M. Guerrero-Bosagna
- Physiology and Environmental Toxicology Program, Department of Organismal Biology, Uppsala University, Uppsala, Sweden
| | | | - Martin Johnsson
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Per Jensen
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
| | - Dominic Wright
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
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Gu Y, Yu W, Qi M, Hu J, Jin Q, Wang X, Wang C, Chen Y, Yuan W. Identification and validation of hub genes and pathways associated with mitochondrial dysfunction in hypertrophy of ligamentum flavum. Front Genet 2023; 14:1117416. [PMID: 37234868 PMCID: PMC10206037 DOI: 10.3389/fgene.2023.1117416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 03/22/2023] [Indexed: 05/28/2023] Open
Abstract
Background: Lumbar spinal stenosis which can lead to irreversible neurologic damage and functional disability, is characterized by hypertrophy of ligamentum flavum (HLF). Recent studies have indicated that mitochondrial dysfunction may contribute to the development of HLF. However, the underlying mechanism is still unclear. Methods: The dataset GSE113212 was obtained from the Gene Expression Omnibus database, and the differentially expressed genes were identified. The intersection of DEGs and mitochondrial dysfunction-related genes were identified as mitochondrial dysfunction-related DEGs. Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and Gene Set Enrichment Analysis were performed. Protein-protein interaction network was constructed, and miRNAs and transcriptional factors of the hub genes were predicted via the miRNet database. Small molecule drugs targeted to these hub genes were predicted via PubChem. Immune infiltration analysis was performed to evaluate the infiltration level of immune cells and their correlation with the hub genes. In final, we measured the mitochondrial function and oxidative stress in vitro and verified the expression of hub genes by qPCR experiments. Results: In total, 43 genes were identified as MDRDEGs. These genes were mainly involved in cellular oxidation, catabolic processes, and the integrity of mitochondrial structure and function. The top hub genes were screened, including LONP1, TK2, SCO2, DBT, TFAM, MFN2. The most significant enriched pathways include cytokine-cytokine receptor interaction, focal adhesion, etc. Besides, SP1, PPARGC1A, YY1, MYC, PPARG, and STAT1 were predicted transcriptional factors of these hub genes. Additionally, increased immune infiltration was demonstrated in HLF, with a close correlation between hub genes and immune cells found. The mitochondrial dysfunction and the expression of hub genes were validated by evaluation of mitochondrial DNA, oxidative stress markers and quantitative real-time PCR. Conclusion: This study applied the integrative bioinformatics analysis and revealed the mitochondrial dysfunction-related key genes, regulatory pathways, TFs, miRNAs, and small molecules underlying the development of HLF, which improved the understanding of molecular mechanisms and the development of novel therapeutic targets for HLF.
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Affiliation(s)
- Yifei Gu
- Department of Orthopaedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Wenchao Yu
- Department of Orthopaedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Min Qi
- Department of Orthopaedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Jinquan Hu
- Department of Orthopaedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Qianmei Jin
- Department of Rheumatology and Immunology, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Xinwei Wang
- Department of Orthopaedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Chen Wang
- Department of Orthopaedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Yu Chen
- Department of Orthopaedics, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Wen Yuan
- Department of Orthopaedics, Changzheng Hospital, Naval Medical University, Shanghai, China
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Bondhus L, Wei A, Arboleda VA. DMRscaler: a scale-aware method to identify regions of differential DNA methylation spanning basepair to multi-megabase features. BMC Bioinformatics 2022; 23:364. [PMID: 36064314 PMCID: PMC9447346 DOI: 10.1186/s12859-022-04899-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 08/22/2022] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Pathogenic mutations in genes that control chromatin function have been implicated in rare genetic syndromes. These chromatin modifiers exhibit extraordinary diversity in the scale of the epigenetic changes they affect, from single basepair modifications by DNMT1 to whole genome structural changes by PRM1/2. Patterns of DNA methylation are related to a diverse set of epigenetic features across this full range of epigenetic scale, making DNA methylation valuable for mapping regions of general epigenetic dysregulation. However, existing methods are unable to accurately identify regions of differential methylation across this full range of epigenetic scale directly from DNA methylation data. RESULTS To address this, we developed DMRscaler, a novel method that uses an iterative windowing procedure to capture regions of differential DNA methylation (DMRs) ranging in size from single basepairs to whole chromosomes. We benchmarked DMRscaler against several DMR callers in simulated and natural data comparing XX and XY peripheral blood samples. DMRscaler was the only method that accurately called DMRs ranging in size from 100 bp to 1 Mb (pearson's r = 0.94) and up to 152 Mb on the X-chromosome. We then analyzed methylation data from rare-disease cohorts that harbor chromatin modifier gene mutations in NSD1, EZH2, and KAT6A where DMRscaler identified novel DMRs spanning gene clusters involved in development. CONCLUSION Taken together, our results show DMRscaler is uniquely able to capture the size of DMR features across the full range of epigenetic scale and identify novel, co-regulated regions that drive epigenetic dysregulation in human disease.
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Affiliation(s)
- Leroy Bondhus
- grid.19006.3e0000 0000 9632 6718Department of Human Genetics, David Geffen School of Medicine, UCLA, 615 Charles E. Young Drive South, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Computational Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA
| | - Angela Wei
- grid.19006.3e0000 0000 9632 6718Department of Human Genetics, David Geffen School of Medicine, UCLA, 615 Charles E. Young Drive South, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Bioinformatics Interdepartmental PhD Program, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Computational Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA
| | - Valerie A. Arboleda
- grid.19006.3e0000 0000 9632 6718Department of Human Genetics, David Geffen School of Medicine, UCLA, 615 Charles E. Young Drive South, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Bioinformatics Interdepartmental PhD Program, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Computational Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Molecular Biology Institute, UCLA, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA 90095 USA
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4
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Lin L, Wang S, Zhang J, Song X, Zhang D, Cheng W, Cui M, Long Y, Xing Z. Integrative analysis of transcriptome and metabolome reveals the effect of DNA methylation of chalcone isomerase gene in promoter region on Lithocarpus polystachyus Rehd flavonoids. Synth Syst Biotechnol 2022; 7:928-940. [PMID: 35664927 PMCID: PMC9149025 DOI: 10.1016/j.synbio.2022.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/26/2022] [Accepted: 05/16/2022] [Indexed: 11/01/2022] Open
Abstract
Metabolite biosynthesis is regulated by gene expression, which is altered by DNA methylation in the promoter region. Chalcone isomerase (CHI) gene encodes a key enzyme in the Lithocarpus polystachyus Rehd flavonoid pathway, and the expression of L. polystachyus CHI (LpCHI) is closely related to the synthesis of flavonoid metabolites. In this study, we analyzed the DNA methylation site of the LpCHI promoter and its effect on gene expression and metabolite accumulation. The proportions of three types of LpCHI promoter DNA methylation are 7.5%, 68.75%, 18.75%, determined by bisulfite sequencing. Transcriptome sequencing shows that LpCHI is strongly up-regulated in LpCHI promoter methylation Type A but down-regulated in LpCHI promoter methylation Type B and Type C. The expression of LpCHI shows no significant difference between Type B and Type C. Moreover, nine kinds of differentially expressed transcription factors (DETFs) bind to seven CpG-sites of the LpCHI promoter region to regulate LpCHI expression. The results of metabolomics show that differentially accumulated flavonoids are higher in LpCHI promoter methylation Type A than in LpCHI promoter methylation Type B and Type C. Additionally, a positive correlation was found between the LpCHI expression and flavonoids accumulation. These results show that the effect of CpG site-specificity on gene transcription is great than that of overall promoter DNA methylation on gene transcription. The mechanisms of flavonoid genes regulating metabolite accumulation are further revealed.
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5
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Rodrigues VL, Dolde U, Sun B, Blaakmeer A, Straub D, Eguen T, Botterweg-Paredes E, Hong S, Graeff M, Li MW, Gendron JM, Wenkel S. A microProtein repressor complex in the shoot meristem controls the transition to flowering. PLANT PHYSIOLOGY 2021; 187:187-202. [PMID: 34015131 PMCID: PMC8418433 DOI: 10.1093/plphys/kiab235] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 05/01/2021] [Indexed: 05/12/2023]
Abstract
MicroProteins are potent post-translational regulators. In Arabidopsis (Arabidopsis thaliana), the miP1a/b microProteins delay floral transition by forming a complex with CONSTANS (CO) and the co-repressor protein TOPLESS. To better understand the function of the miP1a microProtein in floral repression, we performed a genetic suppressor screen to identify suppressors of miP1a (sum) function. One mutant, sum1, exhibited strong suppression of the miP1a-induced late-flowering phenotype. Mapping of sum1 identified another allele of the gene encoding the histone H3K4 demethylase JUMONJI14 (JMJ14), which is required for miP1a function. Plants carrying mutations in JMJ14 exhibit an early flowering phenotype that is largely dependent on CO activity, supporting an additional role for CO in the repressive complex. We further investigated whether miP1a function involves chromatin modification, performed whole-genome methylome sequencing studies with plants ectopically expressing miP1a, and identified differentially methylated regions (DMRs). Among these DMRs is the promoter of FLOWERING LOCUS T (FT), the prime target of miP1a that is ectopically methylated in a JMJ14-dependent manner. Moreover, when aberrantly expressed at the shoot apex, CO induces early flowering, but only when JMJ14 is mutated. Detailed analysis of the genetic interaction among CO, JMJ14, miP1a/b, and TPL revealed a potential role for CO as a repressor of flowering in the shoot apical meristem (SAM). Altogether, our results suggest that a repressor complex operates in the SAM, likely to maintain it in an undifferentiated state until leaf-derived florigen signals induce SAM conversion into a floral meristem.
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Affiliation(s)
- Vandasue L. Rodrigues
- Department of Plant and Environmental Sciences, University of Copenhagen, Denmark
- Copenhagen Plant Science Centre, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Ulla Dolde
- Department of Plant and Environmental Sciences, University of Copenhagen, Denmark
- Copenhagen Plant Science Centre, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Bin Sun
- Department of Plant and Environmental Sciences, University of Copenhagen, Denmark
- Copenhagen Plant Science Centre, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Anko Blaakmeer
- Department of Plant and Environmental Sciences, University of Copenhagen, Denmark
- Copenhagen Plant Science Centre, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Daniel Straub
- Department of Plant and Environmental Sciences, University of Copenhagen, Denmark
- Copenhagen Plant Science Centre, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Tenai Eguen
- Department of Plant and Environmental Sciences, University of Copenhagen, Denmark
- Copenhagen Plant Science Centre, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Esther Botterweg-Paredes
- Department of Plant and Environmental Sciences, University of Copenhagen, Denmark
- Copenhagen Plant Science Centre, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Shinyoung Hong
- Department of Plant and Environmental Sciences, University of Copenhagen, Denmark
- Copenhagen Plant Science Centre, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Moritz Graeff
- Department of Plant and Environmental Sciences, University of Copenhagen, Denmark
- Copenhagen Plant Science Centre, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Man-Wah Li
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven CT 06511, USA
| | - Joshua M. Gendron
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven CT 06511, USA
| | - Stephan Wenkel
- Department of Plant and Environmental Sciences, University of Copenhagen, Denmark
- Copenhagen Plant Science Centre, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
- NovoCrops Center, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
- Author for communication:
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6
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Ming X, Zhu B, Li Y. Mitotic inheritance of DNA methylation: more than just copy and paste. J Genet Genomics 2021; 48:1-13. [PMID: 33771455 DOI: 10.1016/j.jgg.2021.01.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/13/2021] [Accepted: 01/22/2021] [Indexed: 12/14/2022]
Abstract
Decades of investigation on DNA methylation have led to deeper insights into its metabolic mechanisms and biological functions. This understanding was fueled by the recent development of genome editing tools and our improved capacity for analyzing the global DNA methylome in mammalian cells. This review focuses on the maintenance of DNA methylation patterns during mitotic cell division. We discuss the latest discoveries of the mechanisms for the inheritance of DNA methylation as a stable epigenetic memory. We also highlight recent evidence showing the rapid turnover of DNA methylation as a dynamic gene regulatory mechanism. A body of work has shown that altered DNA methylomes are common features in aging and disease. We discuss the potential links between methylation maintenance mechanisms and disease-associated methylation changes.
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Affiliation(s)
- Xuan Ming
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Bing Zhu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Yingfeng Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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7
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Analysis of Il36a induction by C/EBPβ via a half-CRE•C/EBP element in murine macrophages in dependence of its CpG methylation level. Genes Immun 2021; 22:313-321. [PMID: 34697411 PMCID: PMC8674125 DOI: 10.1038/s41435-021-00153-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 11/12/2022]
Abstract
Interleukin-36α is a novel member of the IL-1 cytokine family that is highly expressed in epithelial tissues and several myeloid-derived cell types after induction. The transcription factor (TF) C/EBPβ binds specifically to an essential half-CRE•C/EBP motif in the Il36a promoter to induce Il36a expression upon LPS stimulation. C/EBPs regulate gene expression by binding to recognition sequences that can contain 5'-cytosine-phosphate-guanine-3' dinucleotides (CpG), whose methylation can influence TF binding and gene expression. Herein we show that the half-CRE•C/EBP element in the Il36a promoter is differentially methylated in the murine RAW264.7 macrophage cell line and in primary murine macrophages. We demonstrate that C/EBPβ binding to the half-CRE•C/EBP element in the Il36a promoter following LPS stimulation is insensitive to CpG methylation and that methylation of the CpG in the half-CRE•C/EBP element does not alter LPS-induced Il36a promoter activity which correlated with similar Il36a mRNA copy numbers and pro-IL-36α protein amount in both cell types. Taken together, our data indicate that C/EBPβ binding to the half-CRE•C/EBP element and subsequent gene activation occurs independently of the CpG methylation status of the half-CRE•C/EBP motif and underlines the potential of C/EBPs to recognize methylated as well as unmethylated motifs.
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8
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Höglund A, Henriksen R, Fogelholm J, Churcher AM, Guerrero-Bosagna CM, Martinez-Barrio A, Johnsson M, Jensen P, Wright D. The methylation landscape and its role in domestication and gene regulation in the chicken. Nat Ecol Evol 2020; 4:1713-1724. [PMID: 32958860 DOI: 10.1038/s41559-020-01310-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 08/26/2020] [Indexed: 01/06/2023]
Abstract
Domestication is one of the strongest examples of artificial selection and has produced some of the most extreme within-species phenotypic variation known. In the case of the chicken, it has been hypothesized that DNA methylation may play a mechanistic role in the domestication response. By inter-crossing wild-derived red junglefowl with domestic chickens, we mapped quantitative trait loci for hypothalamic methylation (methQTL), gene expression (eQTL) and behaviour. We find large, stable methylation differences, with 6,179 cis and 2,973 trans methQTL identified. Over 46% of the trans effects were genotypically controlled by five loci, mainly associated with increased methylation in the junglefowl genotype. In a third of eQTL, we find that there is a correlation between gene expression and methylation, while statistical causality analysis reveals multiple instances where methylation is driving gene expression, as well as the reverse. We also show that methylation is correlated with some aspects of behavioural variation in the inter-cross. In conclusion, our data suggest a role for methylation in the regulation of gene expression underlying the domesticated phenotype of the chicken.
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Affiliation(s)
- Andrey Höglund
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
| | - Rie Henriksen
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
| | - Jesper Fogelholm
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
| | | | - Carlos M Guerrero-Bosagna
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden.,Evolutionary Biology Centrum, Dept of Organismal Biology, Uppsala University, Uppsala, Sweden
| | | | - Martin Johnsson
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Edinburgh, UK.,Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Per Jensen
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden
| | - Dominic Wright
- AVIAN Behavioural Genomics and Physiology Group, Linköping University, Linköping, Sweden.
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9
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Rovirosa L, Ramos-Morales A, Javierre BM. The Genome in a Three-Dimensional Context: Deciphering the Contribution of Noncoding Mutations at Enhancers to Blood Cancer. Front Immunol 2020; 11:592087. [PMID: 33117405 PMCID: PMC7575776 DOI: 10.3389/fimmu.2020.592087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 09/21/2020] [Indexed: 11/13/2022] Open
Abstract
Associations between blood cancer and genetic predisposition, including both inherited variants and acquired mutations and epimutations, have been well characterized. However, the majority of these variants affect noncoding regions, making their mechanisms difficult to hypothesize and hindering the translation of these insights into patient benefits. Fueled by unprecedented progress in next-generation sequencing and computational integrative analysis, studies have started applying combinations of epigenetic, genome architecture, and functional assays to bridge the gap between noncoding variants and blood cancer. These complementary tools have not only allowed us to understand the potential malignant role of these variants but also to differentiate key variants, cell-types, and conditions from misleading ones. Here, we briefly review recent studies that have provided fundamental insights into our understanding of how noncoding mutations at enhancers predispose and promote blood malignancies in the context of spatial genome architecture.
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Affiliation(s)
- Llorenç Rovirosa
- 3D Chromatin Organization Group, Josep Carreras Leukaemia Research Institute (IJC), Germans Trias i Pujol, Badalona, Spain
| | - Alberto Ramos-Morales
- 3D Chromatin Organization Group, Josep Carreras Leukaemia Research Institute (IJC), Germans Trias i Pujol, Badalona, Spain
| | - Biola M Javierre
- 3D Chromatin Organization Group, Josep Carreras Leukaemia Research Institute (IJC), Germans Trias i Pujol, Badalona, Spain.,Institute for Health Science Research Germans Trias i Pujol (IGTP), Badalona, Spain
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10
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Sensitivity of transcription factors to DNA methylation. Essays Biochem 2020; 63:727-741. [PMID: 31755929 PMCID: PMC6923324 DOI: 10.1042/ebc20190033] [Citation(s) in RCA: 142] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 10/28/2019] [Accepted: 10/29/2019] [Indexed: 12/17/2022]
Abstract
Dynamic binding of transcription factors (TFs) to regulatory elements controls transcriptional states throughout organism development. Epigenetics modifications, such as DNA methylation mostly within cytosine-guanine dinucleotides (CpGs), have the potential to modulate TF binding to DNA. Although DNA methylation has long been thought to repress TF binding, a more recent model proposes that TF binding can also inhibit DNA methylation. Here, we review the possible scenarios by which DNA methylation and TF binding affect each other. Further in vivo experiments will be required to generalize these models.
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11
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Fielding BA, Calder PC, Irvine NA, Miles EA, Lillycrop KA, von Gerichten J, Burdge GC. How does polyunsaturated fatty acid biosynthesis regulate T‐lymphocyte function? NUTR BULL 2019. [DOI: 10.1111/nbu.12404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- B. A. Fielding
- Faculty of Health and Medical Sciences University of Surrey Guildford UK
| | - P. C. Calder
- School of Human Development and Health Faculty of Medicine University of Southampton Southampton UK
- NIHR Southampton Biomedical Research Centre University Hospital Southampton NHS Foundation Trust, University of Southampton Southampton UK
| | - N. A. Irvine
- School of Human Development and Health Faculty of Medicine University of Southampton Southampton UK
| | - E. A. Miles
- School of Human Development and Health Faculty of Medicine University of Southampton Southampton UK
| | - K. A. Lillycrop
- Centre for Biological Sciences Faculty of Natural and Environmental Sciences University of Southampton Southampton UK
| | - J. von Gerichten
- Faculty of Health and Medical Sciences University of Surrey Guildford UK
| | - G. C. Burdge
- School of Human Development and Health Faculty of Medicine University of Southampton Southampton UK
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12
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Genetic and epigenetic pathways in Down syndrome: Insights to the brain and immune system from humans and mouse models. PROGRESS IN BRAIN RESEARCH 2019; 251:1-28. [PMID: 32057305 DOI: 10.1016/bs.pbr.2019.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The presence of an extra copy of human chromosome 21 (Hsa21) leads to a constellation of phenotypic manifestations in Down syndrome (DS), including prominent effects on the brain and immune system. Intensive efforts to unravel the molecular mechanisms underlying these phenotypes may help developing effective therapies, both in DS and in the general population. Here we review recent progress in genetic and epigenetic analysis of trisomy 21 (Ts21). New mouse models of DS based on syntenic conservation of segments of the mouse and human chromosomes are starting to clarify the contributions of chromosomal subregions and orthologous genes to specific phenotypes in DS. The expression of genes on Hsa21 is regulated by epigenetic mechanisms, and with recent findings of highly recurrent gene-specific changes in DNA methylation patterns in brain and immune system cells with Ts21, the epigenomics of DS has become an active research area. Here we highlight the value of combining human studies with mouse models for defining DS critical genes and understanding the trans-acting effects of a simple chromosomal aneuploidy on genome-wide epigenetic patterning. These genetic and epigenetic studies are starting to uncover fundamental biological mechanisms, leading to insights that may soon become therapeutically relevant.
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13
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Hodges AJ, Hudson NO, Buck-Koehntop BA. Cys 2His 2 Zinc Finger Methyl-CpG Binding Proteins: Getting a Handle on Methylated DNA. J Mol Biol 2019:S0022-2836(19)30567-4. [PMID: 31628952 DOI: 10.1016/j.jmb.2019.09.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 09/13/2019] [Accepted: 09/16/2019] [Indexed: 12/12/2022]
Abstract
DNA methylation is an essential epigenetic modification involved in the maintenance of genomic stability, preservation of cellular identity, and regulation of the transcriptional landscape needed to maintain cellular function. In an increasing number of disease conditions, DNA methylation patterns are inappropriately distributed in a manner that supports the disease phenotype. Methyl-CpG binding proteins (MBPs) are specialized transcription factors that read and translate methylated DNA signals into recruitment of protein assemblies that can alter local chromatin architecture and transcription. MBPs thus play a key intermediary role in gene regulation for both normal and diseased cells. Here, we highlight established and potential structure-function relationships for the best characterized members of the zinc finger (ZF) family of MBPs in propagating DNA methylation signals into downstream cellular responses. Current and future investigations aimed toward expanding our understanding of ZF MBP cellular roles will provide needed mechanistic insight into normal and disease state functions, as well as afford evaluation for the potential of these proteins as epigenetic-based therapeutic targets.
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Affiliation(s)
- Amelia J Hodges
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT, 84112, USA
| | - Nicholas O Hudson
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT, 84112, USA
| | - Bethany A Buck-Koehntop
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT, 84112, USA.
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14
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Hudson NO, Buck-Koehntop BA. Zinc Finger Readers of Methylated DNA. Molecules 2018; 23:E2555. [PMID: 30301273 PMCID: PMC6222495 DOI: 10.3390/molecules23102555] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/03/2018] [Accepted: 10/05/2018] [Indexed: 01/07/2023] Open
Abstract
DNA methylation is a prevalent epigenetic modification involved in regulating a number of essential cellular processes, including genomic accessibility and transcriptional outcomes. As such, aberrant alterations in global DNA methylation patterns have been associated with a growing number of disease conditions. Nevertheless, the full mechanisms by which DNA methylation information is interpreted and translated into genomic responses is not yet fully understood. Methyl-CpG binding proteins (MBPs) function as important mediators of this essential process by selectively reading DNA methylation signals and translating this information into down-stream cellular outcomes. The Cys₂His₂ zinc finger scaffold is one of the most abundant DNA binding motifs found within human transcription factors, yet only a few zinc finger containing proteins capable of conferring selectivity for mCpG over CpG sites have been characterized. This review summarizes our current structural understanding for the mechanisms by which the zinc finger MBPs evaluated to date read this essential epigenetic mark. Further, some of the biological implications for mCpG readout elicited by this family of MBPs are discussed.
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Affiliation(s)
- Nicholas O Hudson
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112-0850, USA.
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15
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Westervelt N, Chadwick BP. Characterization of the ICCE Repeat in Mammals Reveals an Evolutionary Relationship with the DXZ4 Macrosatellite through Conserved CTCF Binding Motifs. Genome Biol Evol 2018; 10:2190-2204. [PMID: 30102341 PMCID: PMC6125249 DOI: 10.1093/gbe/evy176] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2018] [Indexed: 12/16/2022] Open
Abstract
Appreciation is growing for how chromosomes are organized in three-dimensional space at interphase. Microscopic and high throughput sequence-based studies have established that the mammalian inactive X chromosome (Xi) adopts an alternate conformation relative to the active X chromosome. The Xi is organized into several multi-megabase chromatin loops called superloops. At the base of these loops are superloop anchors, and in humans three of these anchors are composed of large tandem repeat DNA that include DXZ4, Functional Intergenic Repeating RNA Element, and Inactive-X CTCF-binding Contact Element (ICCE). Each repeat contains a high density of binding sites for the architectural organization protein CCCTC-binding factor (CTCF) which exclusively associates with the Xi allele in normal cells. Removal of DXZ4 from the Xi compromises proper folding of the chromosome. In this study, we report the characterization of the ICCE tandem repeat, for which very little is known. ICCE is embedded within an intron of the Nobody (NBDY) gene locus at Xp11.21. We find that primary DNA sequence conservation of ICCE is only retained in higher primates, but that ICCE orthologs exist beyond the primate lineage. Like DXZ4, what is conserved is organization of the underlying DNA into a large tandem repeat, physical location within the NBDY locus and conservation of short DNA sequences corresponding to specific CTCF and Yin Yang 1 binding motifs that correlate with female-specific DNA hypomethylation. Unlike DXZ4, ICCE is not common to all eutherian mammals. Analysis of certain ICCE CTCF motifs reveal striking similarity with the DXZ4 motif and support an evolutionary relationship between DXZ4 and ICCE.
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Affiliation(s)
- Natalia Westervelt
- Department of Biological Science, Florida State University, King Life Science Building
| | - Brian P Chadwick
- Department of Biological Science, Florida State University, King Life Science Building
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16
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Sibbons CM, Irvine NA, Pérez-Mojica JE, Calder PC, Lillycrop KA, Fielding BA, Burdge GC. Polyunsaturated Fatty Acid Biosynthesis Involving Δ8 Desaturation and Differential DNA Methylation of FADS2 Regulates Proliferation of Human Peripheral Blood Mononuclear Cells. Front Immunol 2018; 9:432. [PMID: 29556240 PMCID: PMC5844933 DOI: 10.3389/fimmu.2018.00432] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 02/19/2018] [Indexed: 12/12/2022] Open
Abstract
Polyunsaturated fatty acids (PUFAs) are important for immune function. Limited evidence indicates that immune cell activation involves endogenous PUFA synthesis, but this has not been characterised. To address this, we measured metabolism of 18:3n-3 in quiescent and activated peripheral blood mononuclear cells (PBMCs), and in Jurkat T cell leukaemia. PBMCs from men and women (n = 34) were incubated with [1-13C]18:3n-3 with or without Concanavalin A (Con. A). 18:3n-3 conversion was undetectable in unstimulated PBMCs, but up-regulated when stimulated. The main products were 20:3n-3 and 20:4n-3, while 18:4n-3 was undetectable, suggesting initial elongation and Δ8 desaturation. PUFA synthesis was 17.4-fold greater in Jurkat cells than PBMCs. The major products of 18:3n-3 conversion in Jurkat cells were 20:4n-3, 20:5n-3, and 22:5n-3. 13C Enrichment of 18:4n-3 and 20:3n-3 suggests parallel initial elongation and Δ6 desaturation. The FADS2 inhibitor SC26196 reduced PBMC, but not Jurkat cell, proliferation suggesting PUFA synthesis is involved in regulating mitosis in PBMCs. Con. A stimulation increased FADS2, FADS1, ELOVL5 and ELOVL4 mRNA expression in PBMCs. A single transcript corresponding to the major isoform of FADS2, FADS20001, was detected in PBMCs and Jurkat cells. PBMC activation induced hypermethylation of a 470bp region in the FADS2 5'-regulatory sequence. This region was hypomethylated in Jurkat cells compared to quiescent PBMCs. These findings show that PUFA synthesis involving initial elongation and Δ8 desaturation is involved in regulating PBMC proliferation and is regulated via transcription possibly by altered DNA methylation. These processes were dysregulated in Jurkat cells. This has implications for understanding the regulation of mitosis in normal and transformed lymphocytes.
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Affiliation(s)
- Charlene M Sibbons
- Academic Unit of Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, Hampshire, United Kingdom.,Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, United Kingdom
| | - Nicola A Irvine
- Academic Unit of Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, Hampshire, United Kingdom
| | - J Eduardo Pérez-Mojica
- Academic Unit of Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, Hampshire, United Kingdom
| | - Philip C Calder
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, University of Southampton, Southampton, Hampshire, United Kingdom
| | - Karen A Lillycrop
- Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, Hampshire, United Kingdom
| | - Barbara A Fielding
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, United Kingdom
| | - Graham C Burdge
- Academic Unit of Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, Hampshire, United Kingdom
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17
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Yin Y, Morgunova E, Jolma A, Kaasinen E, Sahu B, Khund-Sayeed S, Das PK, Kivioja T, Dave K, Zhong F, Nitta KR, Taipale M, Popov A, Ginno PA, Domcke S, Yan J, Schübeler D, Vinson C, Taipale J. Impact of cytosine methylation on DNA binding specificities of human transcription factors. Science 2018; 356:356/6337/eaaj2239. [PMID: 28473536 DOI: 10.1126/science.aaj2239] [Citation(s) in RCA: 671] [Impact Index Per Article: 111.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 03/09/2017] [Indexed: 12/17/2022]
Abstract
The majority of CpG dinucleotides in the human genome are methylated at cytosine bases. However, active gene regulatory elements are generally hypomethylated relative to their flanking regions, and the binding of some transcription factors (TFs) is diminished by methylation of their target sequences. By analysis of 542 human TFs with methylation-sensitive SELEX (systematic evolution of ligands by exponential enrichment), we found that there are also many TFs that prefer CpG-methylated sequences. Most of these are in the extended homeodomain family. Structural analysis showed that homeodomain specificity for methylcytosine depends on direct hydrophobic interactions with the methylcytosine 5-methyl group. This study provides a systematic examination of the effect of an epigenetic DNA modification on human TF binding specificity and reveals that many developmentally important proteins display preference for mCpG-containing sequences.
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Affiliation(s)
- Yimeng Yin
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE 141 83 Stockholm, Sweden
| | - Ekaterina Morgunova
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE 141 83 Stockholm, Sweden
| | - Arttu Jolma
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE 141 83 Stockholm, Sweden
| | - Eevi Kaasinen
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE 141 83 Stockholm, Sweden
| | - Biswajyoti Sahu
- Genome-Scale Biology Program, Post Office Box 63, FI-00014 University of Helsinki, Helsinki, Finland
| | - Syed Khund-Sayeed
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Room 3128, Building 37, Bethesda, MD 20892, USA
| | - Pratyush K Das
- Genome-Scale Biology Program, Post Office Box 63, FI-00014 University of Helsinki, Helsinki, Finland
| | - Teemu Kivioja
- Genome-Scale Biology Program, Post Office Box 63, FI-00014 University of Helsinki, Helsinki, Finland
| | - Kashyap Dave
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE 141 83 Stockholm, Sweden
| | - Fan Zhong
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE 141 83 Stockholm, Sweden
| | - Kazuhiro R Nitta
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE 141 83 Stockholm, Sweden
| | - Minna Taipale
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE 141 83 Stockholm, Sweden
| | - Alexander Popov
- European Synchrotron Radiation Facility, 38043 Grenoble, France
| | - Paul A Ginno
- Friedrich-Miescher-Institute for Biomedical Research (FMI), Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Silvia Domcke
- Friedrich-Miescher-Institute for Biomedical Research (FMI), Maulbeerstrasse 66, 4058 Basel, Switzerland.,Faculty of Science, University of Basel, Petersplatz 1, 4003 Basel, Switzerland
| | - Jian Yan
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE 141 83 Stockholm, Sweden
| | - Dirk Schübeler
- Friedrich-Miescher-Institute for Biomedical Research (FMI), Maulbeerstrasse 66, 4058 Basel, Switzerland.,Faculty of Science, University of Basel, Petersplatz 1, 4003 Basel, Switzerland
| | - Charles Vinson
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Room 3128, Building 37, Bethesda, MD 20892, USA
| | - Jussi Taipale
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE 141 83 Stockholm, Sweden. .,Genome-Scale Biology Program, Post Office Box 63, FI-00014 University of Helsinki, Helsinki, Finland
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18
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Tsuboi K, Nagatomo T, Gohno T, Higuchi T, Sasaki S, Fujiki N, Kurosumi M, Takei H, Yamaguchi Y, Niwa T, Hayashi SI. Single CpG site methylation controls estrogen receptor gene transcription and correlates with hormone therapy resistance. J Steroid Biochem Mol Biol 2017; 171:209-217. [PMID: 28412323 DOI: 10.1016/j.jsbmb.2017.04.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 03/14/2017] [Accepted: 04/06/2017] [Indexed: 12/19/2022]
Abstract
Hormone therapy is the most effective treatment for patients with estrogen receptor α-positive breast cancers. However, although resistance occurs during treatment in some cases and often reflects changed estrogen receptor α status, the relationship between changes in estrogen receptor α expression and resistance to therapy are poorly understood. In this study, we identified a mechanism for altered estrogen receptor α expression during disease progression and acquired hormone therapy resistance in aromatase inhibitor-resistant breast cancer cell lines. Subsequently, we investigated promoter switching and DNA methylation status of the estrogen receptor α promoter, and found marked changes of methylation at a single CpG site (CpG4) in resistant cells. In addition, luciferase reporter assays showed reduced transcriptional activity from this methylated CpG site. This CpG region was also completely conserved among species, suggesting that it acts as a methylation-sensitive Ets-2 transcription factor binding site, as confirmed using chromatin immunoprecipitation assays. In estrogen receptor α-positive tumors, CpG4 methylation levels were inversely correlated with estrogen receptor α expression status, suggesting that single CpG site plays an important role in the regulation of estrogen receptor α transcription.
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Affiliation(s)
- Kouki Tsuboi
- Department of Molecular and Functional Dynamics, Graduate School of Medicine, Tohoku University, Aoba-ku, Sendai, 980-8575, Japan
| | - Takamasa Nagatomo
- Department of Molecular and Functional Dynamics, Graduate School of Medicine, Tohoku University, Aoba-ku, Sendai, 980-8575, Japan
| | - Tatsuyuki Gohno
- Department of Molecular and Functional Dynamics, Graduate School of Medicine, Tohoku University, Aoba-ku, Sendai, 980-8575, Japan
| | - Toru Higuchi
- Department of Molecular and Functional Dynamics, Graduate School of Medicine, Tohoku University, Aoba-ku, Sendai, 980-8575, Japan
| | - Shunta Sasaki
- Department of Molecular and Functional Dynamics, Graduate School of Medicine, Tohoku University, Aoba-ku, Sendai, 980-8575, Japan
| | - Natsu Fujiki
- Department of Molecular and Functional Dynamics, Graduate School of Medicine, Tohoku University, Aoba-ku, Sendai, 980-8575, Japan
| | - Masafumi Kurosumi
- Department of Pathology, Saitama Cancer Center, Ina-machi, Saitama, 362-0806, Japan
| | - Hiroyuki Takei
- Division of Breast Surgery, Saitama Cancer Center, Ina-machi, Saitama, 362-0806, Japan
| | - Yuri Yamaguchi
- Resarch Institute for Clinical Oncology, Saitama Cancer Center, Ina-machi, Saitama, 362-0806, Japan
| | - Toshifumi Niwa
- Department of Molecular and Functional Dynamics, Graduate School of Medicine, Tohoku University, Aoba-ku, Sendai, 980-8575, Japan
| | - Shin-Ichi Hayashi
- Department of Molecular and Functional Dynamics, Graduate School of Medicine, Tohoku University, Aoba-ku, Sendai, 980-8575, Japan; Center for Regulatory Epigenome and Diseases, Graduate School of Medicine, Tohoku University, Aoba-ku, Sendai, 980-8575, Japan.
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19
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Chen X, Yu B, Carriero N, Silva C, Bonneau R. Mocap: large-scale inference of transcription factor binding sites from chromatin accessibility. Nucleic Acids Res 2017; 45:4315-4329. [PMID: 28334916 PMCID: PMC5416775 DOI: 10.1093/nar/gkx174] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 02/28/2017] [Accepted: 03/06/2017] [Indexed: 12/21/2022] Open
Abstract
Differential binding of transcription factors (TFs) at cis-regulatory loci drives the differentiation and function of diverse cellular lineages. Understanding the regulatory interactions that underlie cell fate decisions requires characterizing TF binding sites (TFBS) across multiple cell types and conditions. Techniques, e.g. ChIP-Seq can reveal genome-wide patterns of TF binding, but typically requires laborious and costly experiments for each TF-cell-type (TFCT) condition of interest. Chromosomal accessibility assays can connect accessible chromatin in one cell type to many TFs through sequence motif mapping. Such methods, however, rarely take into account that the genomic context preferred by each factor differs from TF to TF, and from cell type to cell type. To address the differences in TF behaviors, we developed Mocap, a method that integrates chromatin accessibility, motif scores, TF footprints, CpG/GC content, evolutionary conservation and other factors in an ensemble of TFCT-specific classifiers. We show that integration of genomic features, such as CpG islands improves TFBS prediction in some TFCT. Further, we describe a method for mapping new TFCT, for which no ChIP-seq data exists, onto our ensemble of classifiers and show that our cross-sample TFBS prediction method outperforms several previously described methods.
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Affiliation(s)
- Xi Chen
- Department of Biology, New York University, New York, NY 10003, USA
| | - Bowen Yu
- Department of Computer Science, New York University, New York, NY 10003, USA
| | - Nicholas Carriero
- Center for Computational Biology, Flatiron Foundation, Simons Foundation, New York, NY 10010, USA
| | - Claudio Silva
- Department of Computer Science, New York University, New York, NY 10003, USA
| | - Richard Bonneau
- Department of Biology, New York University, New York, NY 10003, USA
- Department of Computer Science, New York University, New York, NY 10003, USA
- Center for Computational Biology, Flatiron Foundation, Simons Foundation, New York, NY 10010, USA
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20
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High resolution methylation analysis of the HoxA5 regulatory region in different somatic tissues of laboratory mouse during development. Gene Expr Patterns 2017; 23-24:59-69. [DOI: 10.1016/j.gep.2017.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 02/02/2017] [Accepted: 03/26/2017] [Indexed: 11/18/2022]
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21
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Stephens DC, Poon GMK. Differential sensitivity to methylated DNA by ETS-family transcription factors is intrinsically encoded in their DNA-binding domains. Nucleic Acids Res 2016; 44:8671-8681. [PMID: 27270080 PMCID: PMC5062964 DOI: 10.1093/nar/gkw528] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 05/30/2016] [Indexed: 01/25/2023] Open
Abstract
Transactivation by the ETS family of transcription factors, whose members share structurally conserved DNA-binding domains, is variably sensitive to methylation of their target genes. The mechanism by which DNA methylation controls ETS proteins remains poorly understood. Uncertainly also pervades the effects of hemi-methylated DNA, which occurs following DNA replication and in response to hypomethylating agents, on site recognition by ETS proteins. To address these questions, we measured the affinities of two sequence-divergent ETS homologs, PU.1 and Ets-1, to DNA sites harboring a hemi- and fully methylated CpG dinucleotide. While the two proteins bound unmethylated DNA with indistinguishable affinity, their affinities to methylated DNA are markedly heterogeneous and exhibit major energetic coupling between the two CpG methylcytosines. Analysis of simulated DNA and existing co-crystal structures revealed that hemi-methylation induced non-local backbone and groove geometries that were not conserved in the fully methylated state. Indirect readout of these perturbations was differentially achieved by the two ETS homologs, with the distinctive interfacial hydration in PU.1/DNA binding moderating the inhibitory effects of DNA methylation on binding. This data established a biophysical basis for the pioneering properties associated with PU.1, which robustly bound fully methylated DNA, but not Ets-1, which was substantially inhibited.
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Affiliation(s)
| | - Gregory M K Poon
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
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22
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A prominent and conserved role for YY1 in Xist transcriptional activation. Nat Commun 2014; 5:4878. [PMID: 25209548 PMCID: PMC4172967 DOI: 10.1038/ncomms5878] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 08/01/2014] [Indexed: 01/21/2023] Open
Abstract
Accumulation of the non-coding RNA Xist on one X chromosome in female cells is a hallmark of X-chromosome inactivation in eutherians. Here, we uncovered an essential function for the ubiquitous autosomal transcription factor Yin-Yang 1 (YY1) in the transcriptional activation of Xist in both human and mouse. We show that loss of YY1 prevents Xist up-regulation during the initiation and maintenance of X-inactivation, and that YY1 binds directly the Xist 5′ region to trigger the activity of the Xist promoter. Binding of YY1 to the Xist 5′ region prior to X-chromosome inactivation competes with the Xist repressor REX1 while DNA methylation controls mono-allelic fixation of YY1 to Xist at the onset of X-chromosome inactivation. YY1 is thus the first autosomal activating factor involved in a fundamental and conserved pathway of Xist regulation that ensures the asymmetric transcriptional up-regulation of the master regulator of X-chromosome inactivation.
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23
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Clarke-Harris R, Wilkin TJ, Hosking J, Pinkney J, Jeffery AN, Metcalf BS, Godfrey KM, Voss LD, Lillycrop KA, Burdge GC. PGC1α promoter methylation in blood at 5-7 years predicts adiposity from 9 to 14 years (EarlyBird 50). Diabetes 2014; 63:2528-37. [PMID: 24622795 DOI: 10.2337/db13-0671] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The early environment, acting via epigenetic processes, is associated with differential risk of cardiometabolic disease (CMD), which can be predicted by epigenetic marks in proxy tissues. However, such measurements at time points disparate from the health outcome or the environmental exposure may be confounded by intervening stochastic and environmental variation. To address this, we analyzed DNA methylation in the peroxisome proliferator-activated receptor γ coactivator 1α promoter in blood from 40 children (20 boys) collected annually between 5 and 14 years of age by pyrosequencing. Body composition was measured annually by dual X-ray absorptiometry, physical activity by accelerometry, and pubertal timing by age at peak high velocity. The effect of methylation on transcription factor binding was investigated by electrophoretic mobility shift assays. Seven cytosine guanine dinucleotide (CpG) loci were identified that showed no significant temporal change or association with leukocyte populations. Modeling using generalized estimating equations showed that methylation of four loci predicted adiposity up to 14 years independent of sex, age, pubertal timing, and activity. Methylation of one predictive locus modified binding of the proadipogenic pre-B-cell leukemia homeobox-1/homeobox 9 complex. These findings suggest that temporally stable CpG loci measured in childhood may have utility in predicting CMD risk.
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Affiliation(s)
- Rebecca Clarke-Harris
- Academic Unit of Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, U.K.National Institute for Health Research Southampton Biomedical Research Centre, University of Southampton, and University Hospital Southampton National Health Service Foundation Trust, Southampton, U.K
| | | | - Joanne Hosking
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth, U.K
| | - Jonathan Pinkney
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth, U.K
| | - Alison N Jeffery
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth, U.K
| | | | - Keith M Godfrey
- National Institute for Health Research Southampton Biomedical Research Centre, University of Southampton, and University Hospital Southampton National Health Service Foundation Trust, Southampton, U.K.Medical Research Council Lifecourse Epidemiology Unit, University of Southampton, Southampton, U.K
| | - Linda D Voss
- Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth, U.K
| | - Karen A Lillycrop
- Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, U.K.
| | - Graham C Burdge
- Academic Unit of Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, U.K
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24
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Mensaert K, Denil S, Trooskens G, Van Criekinge W, Thas O, De Meyer T. Next-generation technologies and data analytical approaches for epigenomics. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2014; 55:155-70. [PMID: 24327356 DOI: 10.1002/em.21841] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 11/27/2013] [Accepted: 11/27/2013] [Indexed: 05/18/2023]
Abstract
Epigenetics refers to the collection of heritable features that modulate the genome-environment interaction without being encoded in the actual DNA sequence. While being mitotically and sometimes even meiotically transmitted, epigenetic traits often demonstrate extensive flexibility. This allows cells to acquire diverse gene expression patterns during differentiation, but also to adapt to a changing environment. However, epigenetic alterations are not always beneficial to the organism, as they are, for example, frequently identified in human diseases such as cancer. Accurate and cost-efficient genome-scale profiling of epigenetic features is thus of major importance to pinpoint these "epimutations," for example, to monitor the epigenetic impact of environmental exposure. Over the last decade, the field of epigenetics has been revolutionized by several innovative "epigenomics" technologies exactly addressing this need. In this review, we discuss and compare widely used next-generation methods to assess DNA methylation and hydroxymethylation, noncoding RNA expression, histone modifications, and nucleosome positioning. Although recent methods are typically based on "second-generation" sequencing, we also pay attention to still commonly used array- and PCR-based methods, and look forward to the additional advantages of single-molecule sequencing. As the current bottleneck in epigenomics research is the analysis rather than generation of data, the basic difficulties and problem-solving strategies regarding data preprocessing and statistical analysis are introduced for the different technologies. Finally, we also consider the complications associated with epigenomic studies of species with yet unsequenced genomes and possible solutions.
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Affiliation(s)
- Klaas Mensaert
- Department of Mathematical Modelling, Statistics and Bioinformatics, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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26
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Ramirez K, Chandler KJ, Spaulding C, Zandi S, Sigvardsson M, Graves BJ, Kee BL. Gene deregulation and chronic activation in natural killer cells deficient in the transcription factor ETS1. Immunity 2012; 36:921-32. [PMID: 22608498 DOI: 10.1016/j.immuni.2012.04.006] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 03/02/2012] [Accepted: 04/19/2012] [Indexed: 01/01/2023]
Abstract
Multiple transcription factors guide the development of mature functional natural killer (NK) cells, yet little is known about their function. We used global gene expression and genome-wide binding analyses combined with developmental and functional studies to unveil three roles for the ETS1 transcription factor in NK cells. ETS1 functions at the earliest stages of NK cell development to promote expression of critical transcriptional regulators including T-BET and ID2, NK cell receptors (NKRs) including NKp46, Ly49H, and Ly49D, and signaling molecules essential for NKR function. As a consequence, Ets1(-/-) NK cells fail to degranulate after stimulation through activating NKRs. Nonetheless, these cells are hyperresponsive to cytokines and have characteristics of chronic stimulation including increased expression of inhibitory NKRs and multiple activation-associated genes. Therefore, ETS1 regulates a broad gene expression program in NK cells that promotes target cell recognition while limiting cytokine-driven activation.
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Affiliation(s)
- Kevin Ramirez
- Committee on Immunology, The University of Chicago, Chicago, IL 60615, USA
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Abstract
INTRODUCTION The recent DNA methylation studies on cancers have revealed the necessity of profiling an entire human genome and not to restrict the profiling to specific regions of the human genome. It has been suggested that genome-wide DNA methylation analysis enables us to identify the genes that are regulated by DNA methylation in carcinogenesis. METHODS So, we performed whole-genome DNA methylation analysis for human lung squamous cell carcinoma (SCC), which is strongly related with smoking. We also performed microarrays using 21 pairs of normal lung tissues and tumors from patients with SCC. By combining these data, 30 hypermethylated and down-regulated genes, and 22 hypomethylated and up-regulated genes were selected. The gene expression level and DNA methylation pattern were confirmed by semiquantitative reverse-transcriptase polymerase chain reaction and pyrosequencing, respectively. RESULTS By these validations, we selected five hypermethylated and down-regulated genes and one hypomethylated and up-regulated gene. Moreover, these six genes were proven to be actually regulated by DNA methylation by confirming the recovery of their DNA methylation pattern and gene expression level using a demethylating agent. The DNA methylation pattern of the CYTL1 promoter region was significantly different between early and advanced stages of SCC. CONCLUSION In conclusion, by combining the whole-genome DNA methylation pattern and the gene expression profile, we identified the six genes (CCDC37, CYTL1, CDO1, SLIT2, LMO3, and SERPINB5) that are regulated by DNA methylation, and we suggest their value as target molecules for further study of SCC.
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Snellenberg S, Schütze DM, Claassen-Kramer D, Meijer CJ, Snijders PJ, Steenbergen RD. Methylation status of the E2 binding sites of HPV16 in cervical lesions determined with the Luminex® xMAP™ system. Virology 2012; 422:357-65. [DOI: 10.1016/j.virol.2011.11.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 09/13/2011] [Accepted: 11/04/2011] [Indexed: 12/29/2022]
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Moseley SC, Rizkallah R, Tremblay DC, Anderson BR, Hurt MM, Chadwick BP. YY1 associates with the macrosatellite DXZ4 on the inactive X chromosome and binds with CTCF to a hypomethylated form in some male carcinomas. Nucleic Acids Res 2011; 40:1596-608. [PMID: 22064860 PMCID: PMC3287207 DOI: 10.1093/nar/gkr964] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
DXZ4 is an X-linked macrosatellite composed of 12–100 tandemly arranged 3-kb repeat units. In females, it adopts opposite chromatin arrangements at the two alleles in response to X-chromosome inactivation. In males and on the active X chromosome, it is packaged into heterochromatin, but on the inactive X chromosome (Xi), it adopts a euchromatic conformation bound by CTCF. Here we report that the ubiquitous transcription factor YY1 associates with the euchromatic form of DXZ4 on the Xi. The binding of YY1 close to CTCF is reminiscent of that at other epigenetically regulated sequences, including sites of genomic imprinting, and at the X-inactivation centre, suggesting a common mode of action in this arrangement. As with CTCF, binding of YY1 to DXZ4 in vitro is not blocked by CpG methylation, yet in vivo both proteins are restricted to the hypomethylated form. In several male carcinoma cell lines, DXZ4 can adopt a Xi-like conformation in response to cellular transformation, characterized by CpG hypomethylation and binding of YY1 and CTCF. Analysis of a male melanoma cell line and normal skin cells from the same individual confirmed that a transition in chromatin state occurred in response to transformation.
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Affiliation(s)
- Shawn C Moseley
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4295, USA
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Hollenhorst PC, McIntosh LP, Graves BJ. Genomic and biochemical insights into the specificity of ETS transcription factors. Annu Rev Biochem 2011; 80:437-71. [PMID: 21548782 DOI: 10.1146/annurev.biochem.79.081507.103945] [Citation(s) in RCA: 365] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
ETS proteins are a group of evolutionarily related, DNA-binding transcriptional factors. These proteins direct gene expression in diverse normal and disease states by binding to specific promoters and enhancers and facilitating assembly of other components of the transcriptional machinery. The highly conserved DNA-binding ETS domain defines the family and is responsible for specific recognition of a common sequence motif, 5'-GGA(A/T)-3'. Attaining specificity for biological regulation in such a family is thus a conundrum. We present the current knowledge of routes to functional diversity and DNA binding specificity, including divergent properties of the conserved ETS and PNT domains, the involvement of flanking structured and unstructured regions appended to these dynamic domains, posttranslational modifications, and protein partnerships with other DNA-binding proteins and coregulators. The review emphasizes recent advances from biochemical and biophysical approaches, as well as insights from genomic studies that detect ETS-factor occupancy in living cells.
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Affiliation(s)
- Peter C Hollenhorst
- Medical Sciences, Indiana University School of Medicine, Bloomington, Indiana 47405, USA.
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Sekimata M, Murakami-Sekimata A, Homma Y. CpG methylation prevents YY1-mediated transcriptional activation of the vimentin promoter. Biochem Biophys Res Commun 2011; 414:767-72. [PMID: 22005459 DOI: 10.1016/j.bbrc.2011.09.155] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 09/30/2011] [Indexed: 11/15/2022]
Abstract
Vimentin exhibits a complex pattern of tissue-specific and developmentally regulated expression, but the mechanisms underlying the complex transcriptional regulation remain poorly understood. Here we examined whether vimentin expression can be regulated by CpG methylation of the vimentin promoter. Two subclones of the rat C6 glioma cells were established with (C6vim+) and without (C6vim-) vimentin. Bisulfite genomic sequencing revealed that the vicinity of the transcription start site within the vimentin promoter is highly methylated in C6vim- cells but not in C6vim+ cells. Treatment of C6vim- cells with a demethylating agent, 5-aza-2'-deoxycytidine, restored vimentin expression, indicating that hypermethylation of the promoter region correlates with transcriptional silencing of the vimentin gene. Electrophoretic mobility shift assay (EMSA) and transient transfection experiments demonstrated that YY1 is a key transcriptional activator regulating vimentin expression and that CpG methylation is sufficient to prevent the binding of YY1 to the vimentin promoter. These data suggest that the inability of YY1 to access the hypermethylated promoter may be one of the mechanisms that mediate vimentin downregulation.
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Affiliation(s)
- Masayuki Sekimata
- Division of Theoretical Nursing and Genetics, Yamagata University School of Medicine, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan.
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Tsai KW, Hu LY, Wu CW, Li SC, Lai CH, Kao HW, Fang WL, Lin WC. Epigenetic regulation of miR-196b expression in gastric cancer. Genes Chromosomes Cancer 2011; 49:969-80. [PMID: 20662076 DOI: 10.1002/gcc.20804] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
MicroRNAs (miRNAs) are short noncoding RNAs that play important roles in cellular processes and disease pathogenesis via the control of specific targeted gene expression. The miR-196s miRNA is encoded at three paralogous loci in three HOX clusters and acts as an oncogenic miRNA in cancer progression. Recent studies have demonstrated that the expression of miR-196b increases cell proliferation and survival in leukemic cells. Here, we used a sequential methylation analysis to reveal that the methylation status correlated well with miR-196b expression in different cell lines. Treatment with the demethylating drug 5-Aza-dC reactivated miR-196b transcription in methylation-silenced cells. Using in vitro methylation approach, we further provide evidences that promoter hypermethylation represses miR-196b transcriptional activation tightly in human cancer cell lines. We also demonstrate that the expression of miR-196b is significantly elevated in gastric cancer and that hypomethylation status of miR-196b CpG islands frequently is observed in primary gastric tumors. Our results provide important information on miR-196s regulation and demonstrate that abnormal DNA hypomethylation induces overexpression of miR-196b in gastric cancer.
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Affiliation(s)
- Kuo-Wang Tsai
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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Brown C, Campos-León K, Strickland M, Williams C, Fairweather V, Brady RL, Crump MP, Gaston K. Protein flexibility directs DNA recognition by the papillomavirus E2 proteins. Nucleic Acids Res 2010; 39:2969-80. [PMID: 21131281 PMCID: PMC3074142 DOI: 10.1093/nar/gkq1217] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Although DNA flexibility is known to play an important role in DNA–protein interactions, the importance of protein flexibility is less well understood. Here, we show that protein dynamics are important in DNA recognition using the well-characterized human papillomavirus (HPV) type 6 E2 protein as a model system. We have compared the DNA binding properties of the HPV 6 E2 DNA binding domain (DBD) and a mutant lacking two C-terminal leucine residues that form part of the hydrophobic core of the protein. Deletion of these residues results in increased specific and non-specific DNA binding and an overall decrease in DNA binding specificity. Using 15N NMR relaxation and hydrogen/deuterium exchange, we demonstrate that the mutation results in increased flexibility within the hydrophobic core and loop regions that orient the DNA binding helices. Stopped-flow kinetic studies indicate that increased flexibility alters DNA binding by increasing initial interactions with DNA but has little or no effect on the structural rearrangements that follow this step. Taken together these data demonstrate that subtle changes in protein dynamics have a major influence on protein–DNA interactions.
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Affiliation(s)
- Craig Brown
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
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Soufi A, Sawasdichai A, Shukla A, Noy P, Dafforn T, Smith C, Jayaraman PS, Gaston K. DNA compaction by the higher-order assembly of PRH/Hex homeodomain protein oligomers. Nucleic Acids Res 2010; 38:7513-25. [PMID: 20675722 PMCID: PMC2995075 DOI: 10.1093/nar/gkq659] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Protein self-organization is essential for the establishment and maintenance of nuclear architecture and for the regulation of gene expression. We have shown previously that the Proline-Rich Homeodomain protein (PRH/Hex) self-assembles to form oligomeric complexes that bind to arrays of PRH binding sites with high affinity and specificity. We have also shown that many PRH target genes contain suitably spaced arrays of PRH sites that allow this protein to bind and regulate transcription. Here, we use analytical ultracentrifugation and electron microscopy to further characterize PRH oligomers. We use the same techniques to show that PRH oligomers bound to long DNA fragments self-associate to form highly ordered assemblies. Electron microscopy and linear dichroism reveal that PRH oligomers can form protein-DNA fibres and that PRH is able to compact DNA in the absence of other proteins. Finally, we show that DNA compaction is not sufficient for the repression of PRH target genes in cells. We conclude that DNA compaction is a consequence of the binding of large PRH oligomers to arrays of binding sites and that PRH is functionally and structurally related to the Lrp/AsnC family of proteins from bacteria and archaea, a group of proteins formerly thought to be without eukaryotic equivalents.
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Affiliation(s)
- Abdenour Soufi
- Institute for Biomedical Research, Birmingham University Medical School, Edgbaston, Birmingham B15 2TT, UK
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Polansky JK, Schreiber L, Thelemann C, Ludwig L, Krüger M, Baumgrass R, Cording S, Floess S, Hamann A, Huehn J. Methylation matters: binding of Ets-1 to the demethylated Foxp3 gene contributes to the stabilization of Foxp3 expression in regulatory T cells. J Mol Med (Berl) 2010; 88:1029-40. [PMID: 20574810 PMCID: PMC2943068 DOI: 10.1007/s00109-010-0642-1] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 05/21/2010] [Accepted: 05/31/2010] [Indexed: 12/02/2022]
Abstract
The forkhead-box protein P3 (Foxp3) is a key transcription factor for the development and suppressive activity of regulatory T cells (Tregs), a T cell subset critically involved in the maintenance of self-tolerance and prevention of over-shooting immune responses. However, the transcriptional regulation of Foxp3 expression remains incompletely understood. We have previously shown that epigenetic modifications in the CpG-rich Treg-specific demethylated region (TSDR) in the Foxp3 locus are associated with stable Foxp3 expression. We now demonstrate that the methylation state of the CpG motifs within the TSDR controls its transcriptional activity rather than a Treg-specific transcription factor network. By systematically mutating every CpG motif within the TSDR, we could identify four CpG motifs, which are critically determining the transcriptional activity of the TSDR and which serve as binding sites for essential transcription factors, such as CREB/ATF and NF-κB, which have previously been shown to bind to this element. The transcription factor Ets-1 was here identified as an additional molecular player that specifically binds to the TSDR in a demethylation-dependent manner in vitro. Disruption of the Ets-1 binding sites within the TSDR drastically reduced its transcriptional enhancer activity. In addition, we found Ets-1 bound to the demethylated TSDR in ex vivo isolated Tregs, but not to the methylated TSDR in conventional CD4+ T cells. We therefore propose that Ets-1 is part of a larger protein complex, which binds to the TSDR only in its demethylated state, thereby restricting stable Foxp3 expression to the Treg lineage.
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Affiliation(s)
- Julia K Polansky
- Experimental Immunology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
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Sturgill TW, Stoddard PB, Cohn SM, Mayo MW. The promoter for intestinal cell kinase is head-to-head with F-Box 9 and contains functional sites for TCF7L2 and FOXA factors. Mol Cancer 2010; 9:104. [PMID: 20459822 PMCID: PMC2876993 DOI: 10.1186/1476-4598-9-104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Accepted: 05/11/2010] [Indexed: 12/13/2022] Open
Abstract
Background Intestinal cell kinase (ICK; GeneID 22858) is a conserved MAPK and CDK-like kinase that is widely expressed in human tissues. Data from the Cancer Genome Anatomy Project indicated ICK mRNA is increased in cancer, and that its expression correlated with expression of mRNA for an uncharacterized F-box protein, FBX9 (GeneID: 26268). ICK and FBX9 genes are arranged head-to-head on opposite strands, with start sites for transcription separated by ~3.3 kb. We hypothesized ICK and FBX9 are potentially important genes in cancer controlled by a bidirectional promoter. Results We assessed promoter activity of the intergenic region in both orientations in cancer cell lines derived from breast (AU565, SKBR3), colon (HCT-15, KM12), and stomach (AGS) cancers, as well as in embryonic human kidney (HEK293T) cells. The intergenic segment was active in both orientations in all of these lines, and ICK promoter activity was greater than FBX9 promoter activity. Results from deletions and truncations defined a minimal promoter for ICK, and revealed that repressors and enhancers differentially regulate ICK versus FBX9 promoter activity. The ICK promoter contains consensus motifs for several FOX-family transcription factors that align when mouse and human are compared using EMBOSS. FOXA1 and FOXA2 increase luciferase activity of a minimal promoter 10-20 fold in HEK293T cells. Consensus sites for TCF7L2 (TCF4) (Gene Id: 6934) are also present in both mouse and human. The expression of β-catenin increased activity of the minimal promoter ~10 fold. ICK reference mRNAs (NM_014920.3, NM_016513) are expressed in low copy number and increased in some breast cancers, using a ten base tag 5'-TCAACCTTAT-3' specific for both ICK transcripts. Conclusion ICK and FBX9 are divergently transcribed from a bidirectional promoter that is GC-rich and contains a CpG island. A minimal promoter for ICK contains functional sites for β-cateinin/TCF7L2 and FOXA. These data are consistent with functions that have been proposed for ICK in development and in proliferation or survival of some breast and colon cancers.
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Affiliation(s)
- Thomas W Sturgill
- Departments of Pharmacology and Internal Medicine, University of Virginia, 1300 Jefferson Park Avenue, Charlottesville, Virginia 22908, USA.
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Abnormal expression of NRF-2α in hepatocellular carcinoma identified with a newly prepared monoclonal antibody against human NRF-2α protein. Mol Biol Rep 2010; 38:3083-8. [PMID: 20127517 DOI: 10.1007/s11033-010-9976-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2008] [Accepted: 01/19/2010] [Indexed: 12/16/2022]
Abstract
Human nuclear respiratory factor 2 alpha subunit (NRF-2α) is fundamentally important to cell function and the development. We aimed to establish the monoclonal antibody (MAb) against the human NRF-2α protein and to investigate its distribution in human hepatocellular carcinoma (HCC) and tumor-adjacent tissues. The 6× His-NRF-2α fusion protein was successfully induced and purified. One monoclonal antibody (MAb) against human NRF-2α, 1-D10-E1-B11-G3 (IgG1), effective in detecting the recombinant and the cellular protein, was characterized. Using immunohistochemical analysis, the expression of NRF-2α was investigated in 38 cases of HCC specimens and 14 cases of tumor-adjacent specimens. Staining was found positive in 9 cases of HCC tissues (23.7%) and 8 cases of normal hepatic tissues (57.1%). The higher-grade frequency of expression of NRF-2α in tumor-adjacent tissues was significantly higher (P < 0.01) than that in tumor tissues, suggesting that NRF-2α may play important roles in carcinogenesis of HCC.
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Bélanger AS, Tojcic J, Harvey M, Guillemette C. Regulation of UGT1A1 and HNF1 transcription factor gene expression by DNA methylation in colon cancer cells. BMC Mol Biol 2010; 11:9. [PMID: 20096102 PMCID: PMC2835698 DOI: 10.1186/1471-2199-11-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 01/22/2010] [Indexed: 12/13/2022] Open
Abstract
Background UDP-glucuronosyltransferase 1A1 (UGT1A1) is a pivotal enzyme involved in metabolism of SN-38, the active metabolite of irinotecan commonly used to treat metastatic colorectal cancer. We previously demonstrated aberrant methylation of specific CpG dinucleotides in UGT1A1-negative cells, and revealed that methylation state of the UGT1A1 5'-flanking sequence is negatively correlated with gene transcription. Interestingly, one of these CpG dinucleotides (CpG -4) is found close to a HNF1 response element (HRE), known to be involved in activation of UGT1A1 gene expression, and within an upstream stimulating factor (USF) binding site. Results Gel retardation assays revealed that methylation of CpG-4 directly affect the interaction of USF1/2 with its cognate sequence without altering the binding for HNF1-alpha. Luciferase assays sustained a role for USF1/2 and HNF1-alpha in UGT1A1 regulation in colon cancer cells. Based on the differential expression profiles of HNF1A gene in colon cell lines, we also assessed whether methylation affects its expression. In agreement with the presence of CpG islands in the HNF1A promoter, treatments of UGT1A1-negative HCT116 colon cancer cells with a DNA methyltransferase inhibitor restore HNF1A gene expression, as observed for UGT1A1. Conclusions This study reveals that basal UGT1A1 expression in colon cells is positively regulated by HNF1-alpha and USF, and negatively regulated by DNA methylation. Besides, DNA methylation of HNF1A could also play an important role in regulating additional cellular drug metabolism and transporter pathways. This process may contribute to determine local inactivation of drugs such as the anticancer agent SN-38 by glucuronidation and define tumoral response.
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Affiliation(s)
- Anne-Sophie Bélanger
- Pharmacogenomics Laboratory, Centre Hospitalier Universitaire de Québec, 2705 Laurier, Quebec, G1V 4G2, Canada
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Hollenhorst PC, Chandler KJ, Poulsen RL, Johnson WE, Speck NA, Graves BJ. DNA specificity determinants associate with distinct transcription factor functions. PLoS Genet 2009; 5:e1000778. [PMID: 20019798 PMCID: PMC2787013 DOI: 10.1371/journal.pgen.1000778] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 11/18/2009] [Indexed: 12/31/2022] Open
Abstract
To elucidate how genomic sequences build transcriptional control networks, we need to understand the connection between DNA sequence and transcription factor binding and function. Binding predictions based solely on consensus predictions are limited, because a single factor can use degenerate sequence motifs and because related transcription factors often prefer identical sequences. The ETS family transcription factor, ETS1, exemplifies these challenges. Unexpected, redundant occupancy of ETS1 and other ETS proteins is observed at promoters of housekeeping genes in T cells due to common sequence preferences and the presence of strong consensus motifs. However, ETS1 exhibits a specific function in T cell activation; thus, unique transcriptional targets are predicted. To uncover the sequence motifs that mediate specific functions of ETS1, a genome-wide approach, chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq), identified both promoter and enhancer binding events in Jurkat T cells. A comparison with DNase I sensitivity both validated the dataset and also improved accuracy. Redundant occupancy of ETS1 with the ETS protein GABPA occurred primarily in promoters of housekeeping genes, whereas ETS1 specific occupancy occurred in the enhancers of T cell–specific genes. Two routes to ETS1 specificity were identified: an intrinsic preference of ETS1 for a variant of the ETS family consensus sequence and the presence of a composite sequence that can support cooperative binding with a RUNX transcription factor. Genome-wide occupancy of RUNX factors corroborated the importance of this partnership. Furthermore, genome-wide occupancy of co-activator CBP indicated tight co-localization with ETS1 at specific enhancers, but not redundant promoters. The distinct sequences associated with redundant versus specific ETS1 occupancy were predictive of promoter or enhancer location and the ontology of nearby genes. These findings demonstrate that diversity of DNA binding motifs may enable variable transcription factor function at different genomic sites. Genomes contain sequences that encode both gene products and the instructions for where and when each gene is expressed. This gene expression code is critical for normal development and goes awry in disease processes such as cancer. The gene expression code is interpreted by proteins called transcription factors that bind to particular DNA sequences and carry instructions for gene activation or repression. This recognition code is challenged by the presence of highly-similar transcription factors that prefer almost identical DNA sequences. In addition, studies in living cells indicate that individual transcription factors have significant flexibility in sequence recognition. Here, we identify thousands of positions in the genome of human T cells that are bound by the transcription factor ETS1. These data, along with comparisons to other genomic datasets, allow us to identify DNA sequences that specify ETS1 binding while excluding binding of other related transcription factors. Furthermore, we discover that ETS1 binds more than one sequence and that these sequence variants can predict distinct biological functions of ETS1. Thus, this work contributes to our understanding of the gene expression code by addressing both how a transcription factor can bind unique genomic locations and why a transcription factor binds multiple DNA sequences.
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Affiliation(s)
- Peter C. Hollenhorst
- Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, Salt Lake City, Utah, United States of America
| | - Katherine J. Chandler
- Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, Salt Lake City, Utah, United States of America
| | - Rachel L. Poulsen
- Department of Statistics, Brigham Young University, Provo, Utah, United States of America
| | - W. Evan Johnson
- Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, Salt Lake City, Utah, United States of America
- Department of Statistics, Brigham Young University, Provo, Utah, United States of America
| | - Nancy A. Speck
- Abramson Family Cancer Research Institute, Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Barbara J. Graves
- Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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Mirghomizadeh F, Bullwinkel J, Orinska Z, Janssen O, Petersen A, Singh PB, Bulfone-Paus S. Transcriptional regulation of mouse mast cell protease-2 by interleukin-15. J Biol Chem 2009; 284:32635-41. [PMID: 19801677 DOI: 10.1074/jbc.m109.015446] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Mast cells (MCs) play a critical role in innate and adaptive immunity through the release of cytokines, chemokines, lipid mediators, biogenic amines, and proteases. We recently showed that the activities of MC proteases are transcriptionally regulated by intracellularly retained interleukin-15 (IL-15), and we provided evidence that this cytokine acts as a specific regulator of mouse mast cell protease-2 (mMCP-2). Here, we show that in wild-type bone marrow-derived mast cells (BMMCs) IL-15 inhibits mMCP-2 transcription indirectly by inducing differential expression and mMCP-2 promoter binding of the bifunctional transcription factors C/EBPbeta and YY1. In wild-type BMMCs, C/EBPbeta expression predominates over YY1 expression, and thus C/EBPbeta preferentially binds to the mMCP-2 promoter. In IL-15-deficient BMMCs, the opposite is found: YY1 expression predominates and binds to the mMCP-2 promoter at the expense of C/EBPbeta. Hypertranscription of the mMCP-2 gene in IL-15-deficient BMMCs is associated with histone acetylation and, intriguingly, with methylation of non-CpG dinucleotides within the MCP-2 promoter. This suggests a novel model of cytokine-controlled protease transcription: non-CpG methylation maintains a chromosomal domain in an "open" configuration that is permissive for gene expression.
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Affiliation(s)
- Farhad Mirghomizadeh
- Division of Immunobiology, Department of Immunology and Cell Biology, Research Center Borstel, 23845 Borstel, Germany
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Petrovich M, Veprintsev DB. Effects of CpG methylation on recognition of DNA by the tumour suppressor p53. J Mol Biol 2008; 386:72-80. [PMID: 19084536 PMCID: PMC2666794 DOI: 10.1016/j.jmb.2008.11.054] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Revised: 11/25/2008] [Accepted: 11/26/2008] [Indexed: 11/17/2022]
Abstract
Methylation of DNA is one of the mechanisms controlling the expression landscape of the genome. Its pattern is altered in cancer and often results in the hypermethylation of the promoter regions and abnormal expression of tumour suppressor genes. Methylation of CpG dinucleotides located in the binding sites of transcription factors may contribute to the development of cancers by preventing their binding or altering their specificity. We studied the effects of CpG methylation on DNA recognition by the tumour suppressor p53, a transcription factor involved in the response to carcinogenic stress. p53 recognises a large number of DNA sequences, many of which contain CpG dinucleotides. We systematically substituted a CpG dinucleotide at each position in the consensus p53 DNA binding sequence and identified substitutions tolerated by p53. We compared the binding affinities of methylated versus non-methylated sequences by fluorescence anisotropy titration. We found that binding of p53 was not affected by cytosine methylation in a majority of cases. However, for a few sequences containing multiple CpG dinucleotides, such as sites in the RB and Met genes, methylation resulted in a four- to sixfold increase in binding of p53. This approach can be used to quantify the effects of CpG methylation on the DNA recognition by other DNA-binding proteins.
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Affiliation(s)
| | - Dmitry B. Veprintsev
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
- Corresponding author. Fax: +44 1223 412178.
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Ongwijitwat S, Liang HL, Graboyes EM, Wong-Riley MTT. Nuclear respiratory factor 2 senses changing cellular energy demands and its silencing down-regulates cytochrome oxidase and other target gene mRNAs. Gene 2006; 374:39-49. [PMID: 16516409 DOI: 10.1016/j.gene.2006.01.009] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Accepted: 01/09/2006] [Indexed: 10/25/2022]
Abstract
Cytochrome c oxidase (COX), the terminal enzyme of the electron transport chain, is a bigenomic enzyme with 13 subunits. The mechanism coordinating the transcription of these subunits is poorly understood. We investigated the role of nuclear respiratory factor-2 (NRF-2) in intragenomic regulation of nuclear COX genes. Vector-mediated short-hairpin RNA interference against NRF-2alpha reduced all 10 COX nuclear subunit mRNAs and mRNAs of other genes involved in mitochondrial function/biogenesis. NRF-2 binding site was necessary for the rat COX 4i1 promoter to down-regulate in response to decreased energy demands in primary neurons. Over-expression of NRF-2 protein prevented the down-regulation of transcriptional activity by TTX. Finally, NRF-2 binding sites in isolation were sufficient for modulating COX subunit 4i1 and 6A1 promoters' activity in response to decreased energy demand. These results indicate that NRF-2 is a vital part of a molecular mechanism that senses upstream energy signals and modulates COX transcriptional levels in mammalian cells.
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Affiliation(s)
- Sakkapol Ongwijitwat
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
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43
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Stanilova SA, Miteva LD, Karakolev ZT, Stefanov CS. Interleukin-10-1082 promoter polymorphism in association with cytokine production and sepsis susceptibility. Intensive Care Med 2006; 32:260-266. [PMID: 16435103 DOI: 10.1007/s00134-005-0022-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2005] [Accepted: 11/28/2005] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To investigate the -1082 (A/G) polymorphism in the promoter of the IL-10 gene in terms of IL-10 production from stimulated peripheral blood mononuclear cells (PBMC) and to evaluate the relationship of this polymorphism with susceptibility to severe sepsis and the outcome of the disease. DESIGN Case-control study. SETTING Research laboratory of Molecular Biology and Immunology and University Hospital ICU, Faculty of Medicine, Trakia University. PATIENTS A total of 53 healthy volunteers and 33 patients in ICU meeting the criteria for severe sepsis were included. MEASUREMENTS AND RESULTS The amplification refractory mutation system PCR was used for IL-10-1082 polymorphism detection. Isolated PBMC were stimulated with either C3-binding glycoprotein (C3bgp), lipopolysaccharide (LPS), phytohemagglutinin (PHA),or pokeweed mitogen (PWM). IL-10 production was measured in culture supernatants. The AA genotype was associated with lower IL-10 production in LPS-, PHA- or PWM-stimulated healthy PBMC. Patients with severe sepsis had significant elevation of A allele, compared with healthy controls (74.2% vs 52.8%; p=0.0062). Carriage of at least one copy of IL-10-1082 G allele in sepsis patients and in healthy controls resulted in a statistically significant increase in IL-10 production from stimulated PBMC. Surviving sepsis patients had a significant decrease of IL-10-1082 allele G frequency, compared with controls (17% vs 47.2%; p=0.012). An association between increased IL-10 production and poor outcome from sepsis was observed. CONCLUSION The A allele of the -1082 polymorphism in the interleukin-10 gene promoter is associated with sepsis susceptibility, whereas G allele is associated with higher stimulated interleukin-10 production and increased mortality in severe sepsis.
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Affiliation(s)
- Spaska A Stanilova
- Faculty of Medicine, Department of Molecular Biology, Immunology and Genetics, Trakia University, Armeiska 11 St., 6000, Stara Zagora, Bulgaria.
| | - Lyuba D Miteva
- Faculty of Medicine, Department of Molecular Biology, Immunology and Genetics, Trakia University, Armeiska 11 St., 6000, Stara Zagora, Bulgaria
| | - Zhivko T Karakolev
- Department of Intensive Medicine and ICU, Faculty of Medicine, Trakia University, Stara Zagora, Bulgaria
| | - Chavdar S Stefanov
- Department of Anesthesiology and Intensive care, Medical University, Plovdiv, Bulgaria
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Papworth M, Kolasinska P, Minczuk M. Designer zinc-finger proteins and their applications. Gene 2006; 366:27-38. [PMID: 16298089 DOI: 10.1016/j.gene.2005.09.011] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2005] [Accepted: 09/18/2005] [Indexed: 10/25/2022]
Abstract
The Cys(2)His(2) zinc finger is one of the most common DNA-binding motifs in Eukaryota. A simple mode of DNA recognition by the Cys(2)His(2) zinc finger domain provides an ideal scaffold for designing proteins with novel sequence specificities. The ability to bind specifically to virtually any DNA sequence combined with the potential of fusing them with effector domains has led to the technology of engineering of chimeric DNA-modifying enzymes and transcription factors. This in turn has opened the possibility of using the engineered zinc finger-based factors as novel human therapeutics. One such synthetic factor-designer zinc finger transcription activator of the vascular endothelial growth factor A gene-has recently entered clinical trials to evaluate the ability of stimulating the growth of blood vessels in treating the peripheral arterial obstructive disease. This review concentrates on the aspects of natural Cys(2)His(2) zinc fingers evolution and fundamental steps in design of engineered zinc finger proteins. The applications of engineered zinc finger proteins are discussed in a context of the mechanism mediating their effect on the targeted DNA. Furthermore, the regulation of the expression of zinc finger proteins and their targeting to various cellular compartments and to chromatin and non-chromatin target templates are described. Also possible future applications of designer zinc finger proteins are discussed.
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Affiliation(s)
- Monika Papworth
- MRC Laboratory of Molecular Biology, Hills Road, CB2 2QH, UK.
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Maier H, Colbert J, Fitzsimmons D, Clark DR, Hagman J. Activation of the early B-cell-specific mb-1 (Ig-alpha) gene by Pax-5 is dependent on an unmethylated Ets binding site. Mol Cell Biol 2003; 23:1946-60. [PMID: 12612069 PMCID: PMC149480 DOI: 10.1128/mcb.23.6.1946-1960.2003] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methylation of cytosine in CpG dinucleotides promotes transcriptional repression in mammals by blocking transcription factor binding and recruiting methyl-binding proteins that initiate chromatin remodeling. Here, we use a novel cell-based system to show that retrovirally expressed Pax-5 protein activates endogenous early B-cell-specific mb-1 genes in plasmacytoma cells, but only when the promoter is hypomethylated. CpG methylation does not directly affect binding of the promoter by Pax-5. Instead, methylation of an adjacent CpG interferes with assembly of ternary complexes comprising Pax-5 and Ets proteins. In electrophoretic mobility shift assays, recruitment of Ets-1 is blocked by methylation of the Ets site (5'CCGGAG) on the antisense strand. In transfection assays, selective methylation of a single CpG within the Pax-5-dependent Ets site greatly reduces mb-1 promoter activity. Prior demethylation of the endogenous mb-1 promoter is required for its activation by Pax-5 in transduced cells. Although B-lineage cells have only unmethylated mb-1 genes and do not modulate methylation of the mb-1 promoter during development, other tissues feature high percentages of methylated alleles. Together, these studies demonstrate a novel DNA methylation-dependent mechanism for regulating transcriptional activity through the inhibition of DNA-dependent protein-protein interactions.
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MESH Headings
- Animals
- Antigens, CD/genetics
- B-Lymphocytes/metabolism
- Binding Sites
- Bone Marrow Cells/metabolism
- CD79 Antigens
- Cell Lineage
- CpG Islands
- DNA Methylation
- DNA-Binding Proteins/deficiency
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/physiology
- Gene Expression Regulation, Neoplastic
- Humans
- Macromolecular Substances
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- PAX5 Transcription Factor
- Plasma Cells/metabolism
- Plasmacytoma/pathology
- Promoter Regions, Genetic/genetics
- Proto-Oncogene Protein c-ets-1
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-ets
- Receptors, Antigen, B-Cell/genetics
- Recombinant Fusion Proteins/physiology
- Specific Pathogen-Free Organisms
- Transcription Factors/deficiency
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcription Factors/physiology
- Transcription, Genetic/genetics
- Transfection
- Tumor Cells, Cultured
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Affiliation(s)
- Holly Maier
- Integrated Department of Immunology, National Jewish Medical and Research Center, 1400 Jackson Street, K516B, Denver, CO 80206, USA
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Abstract
DNA methylation alterations are now widely recognized as a contributing factor in human tumorigenesis. A significant number of tumor suppressor genes are transcriptionally silenced by promoter hypermethylation, and recent research implicates alterations in chromatin structure as the mechanistic basis for this repression. The enzymes responsible for catalyzing DNA-cytosine methylation, as well as the proteins involved in interpreting the DNA methylation signal, have now been elucidated. Technological advances, including gene expression microarrays and genome scanning techniques, have allowed the comprehensive measurement of DNA methylation changes in human cancers. An important distinction between DNA methylation (epigenetic) and mutation or deletion (genetic) tumor suppressor gene inactivation is that epigenetic inactivation can be abrogated by small molecules, including DNA methyltransferase and histone deacetylase inhibitors. Further, strategies have been developed that combine treatments with drugs that reactivate silenced gene expression with secondary agents that target the re-expressed genes and/or reconstituted signal transduction pathways. In this review, we will discuss in detail the mechanisms of gene silencing by DNA methylation, the techniques used to decipher the complement of methylation-inactivated genes in human cancers, and current and future strategies for reactivating the expression of methylation-silenced genes.
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Affiliation(s)
- Adam R Karpf
- Huntsman Cancer Institute, University of Utah, 2000 Circle of Hope, Salt Lake City, Utah, UT 84112, USA.
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Scarpulla RC. Nuclear activators and coactivators in mammalian mitochondrial biogenesis. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1576:1-14. [PMID: 12031478 DOI: 10.1016/s0167-4781(02)00343-3] [Citation(s) in RCA: 441] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The biogenesis of mitochondria requires the expression of a large number of genes, most of which reside in the nuclear genome. The protein-coding capacity of mtDNA is limited to 13 respiratory subunits necessitating that nuclear regulatory factors play an important role in governing nucleo-mitochondrial interactions. Two classes of nuclear transcriptional regulators implicated in mitochondrial biogenesis have emerged in recent years. The first includes DNA-binding transcription factors, typified by nuclear respiratory factor (NRF)-1, NRF-2 and others, that act on known nuclear genes that specify mitochondrial functions. A second, more recently defined class, includes nuclear coactivators typified by PGC-1 and related family members (PRC and PGC-1 beta). These molecules do not bind DNA but rather work through their interactions with DNA-bound transcription factors to regulate gene expression. An important feature of these coactivators is that their expression is responsive to physiological signals mediating thermogenesis, cell proliferation and gluconeogenesis. Thus, they have the ability to integrate the action of multiple transcription factors in orchestrating programs of gene expression essential to cellular energetics. The interplay of these nuclear factors appears to be a major determinant in regulating the biogenesis of mitochondria.
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Affiliation(s)
- Richard C Scarpulla
- Department of Cell and Molecular Biology, Northwestern Medical School, 303 East Chicago Avenue, Searle 4-458, Chicago, IL 60611, USA.
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Shiraishi M, Oates AJ, Sekiya T. An overview of the analysis of DNA methylation in mammalian genomes. Biol Chem 2002; 383:893-906. [PMID: 12222679 DOI: 10.1515/bc.2002.096] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
DNA methylation at position C5 of the pyrimidine ring of cytosine in mammalian genomes has received a great deal of research interest due to its importance in many biological phenomena. It is associated with events such as epigenetic gene silencing and the maintenance of genome integrity. Aberrant DNA methylation, particularly that of chromosomal regions called CpG islands, is an important step in carcinogenesis. In order to elucidate methylation profiling of complex genomes, various methods have been developed. Many of these methods are based on the differential reactivity of cytosine and 5-methylcytosine to various chemicals. The combined use of these chemical reactions and other preexisting methods has enabled the discrimination of cytosine and 5-methylcytosine in complex genomes. The use of proteins that preferentially bind to methylated DNA has also successfully been used to discriminate between methylated and unmethylated sites. The chemical and structural dissection of the in vivo processes of enzymatic methylation and the binding of methyl-CpG binding proteins provides evidence for the complex mechanisms that nature has acquired. In this review we summarize the methods available for the discrimination between cytosine and 5-methylcytosine in complex genomes.
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Affiliation(s)
- Masahiko Shiraishi
- DNA Methylation and Genome Function Project, National Cancer Center Research Institute, Tokyo, Japan
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49
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Abstract
Cys2His2 zinc finger proteins offer a stable and versatile framework for the design of proteins that recognize desired target sites on double-stranded DNA. Individual fingers from these proteins have a simple beta beta alpha structure that folds around a central zinc ion, and tandem sets of fingers can contact neighboring subsites of 3-4 base pairs along the major groove of the DNA. Although there is no simple, general code for zinc finger-DNA recognition, selection strategies have been developed that allow these proteins to be targeted to almost any desired site on double-stranded DNA. The affinity and specificity of these new proteins can also be improved by linking more fingers together or by designing proteins that bind as dimers and thus recognize an extended site. These new proteins can then be modified by adding other domains--for activation or repression of transcription, for DNA cleavage, or for other activities. Such designer transcription factors and other new proteins will have important applications in biomedical research and in gene therapy.
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Affiliation(s)
- C O Pabo
- Department of Biology, Massachusetts Institute of Technology, Howard Hughes Medical Institute, Cambridge, Massachusetts 02139, USA.
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50
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Müller-Tidow C, Kügler K, Diederichs S, Klümpen S, Möller M, Vogt U, Metzger R, Schneider PM, Berdel WE, Serve H. Loss of expression of HDAC-recruiting methyl-CpG-binding domain proteins in human cancer. Br J Cancer 2001; 85:1168-74. [PMID: 11710831 PMCID: PMC2375156 DOI: 10.1054/bjoc.2001.2041] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dysregulation of CpG-methylation is a common feature of many human cancers and tumour suppressor genes can be silenced by hypermethylation. Recently, 2 methyl-CpG-binding domain proteins have been linked to gene inactivation by their ability to recruit co-repressors and HDAC-activity to methylated gene promoters. Here, we have analysed mRNA expression of these genes, MeCP2 and MBD2, in a wide variety of primary human tumours. In solid tumours, expression levels of MBD2 (57/71) and MeCP2 (64/71) were significantly reduced in the majority of primary tumours as detected by quantitative real-time RT-PCR. Western blot analyses of MeCP2 in matched tumour-normal samples of patients with non-small-cell lung cancer (NSCLC) indicated reduced protein in a significant percentage of patients. In acute myelogenous leukaemia (n = 26), expression levels were only slightly reduced and did not differ between samples analysed at diagnosis or at the time of relapse. In early-stage NSCLC (n = 70) expression of MeCP2 and MBD2 was significantly lower in squamous cell carcinoma than in adenocarcinoma or large cell carcinoma (P = 0.03 and P = 0.01). To further elucidate the mechanisms of gene regulation, we analysed MeCP2 and MBD2 regulation during haematopoietic differentiation. No significant changes in MeCP2 or MBD2 expression were found when NB4 cells were differentiated toward granulocytes suggesting that neither differentiation nor cell cycle status were relevant for the reduced expression of these genes in human cancer. In conclusion, the significant loss of MeCP2 and MBD2 expression in human cancers suggests a potential role of this phenomenon in the development of solid human tumours.
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Affiliation(s)
- C Müller-Tidow
- Department of Medicine, Hematology and Oncology, University of Münster, Germany
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