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Beacon TH, Delcuve GP, López C, Nardocci G, Kovalchuk I, van Wijnen AJ, Davie JR. The dynamic broad epigenetic (H3K4me3, H3K27ac) domain as a mark of essential genes. Clin Epigenetics 2021; 13:138. [PMID: 34238359 PMCID: PMC8264473 DOI: 10.1186/s13148-021-01126-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 06/30/2021] [Indexed: 02/06/2023] Open
Abstract
Transcriptionally active chromatin is marked by tri-methylation of histone H3 at lysine 4 (H3K4me3) located after first exons and around transcription start sites. This epigenetic mark is typically restricted to narrow regions at the 5`end of the gene body, though a small subset of genes have a broad H3K4me3 domain which extensively covers the coding region. Although most studies focus on the H3K4me3 mark, the broad H3K4me3 domain is associated with a plethora of histone modifications (e.g., H3 acetylated at K27) and is therein termed broad epigenetic domain. Genes marked with the broad epigenetic domain are involved in cell identity and essential cell functions and have clinical potential as biomarkers for patient stratification. Reducing expression of genes with the broad epigenetic domain may increase the metastatic potential of cancer cells. Enhancers and super-enhancers interact with the broad epigenetic domain marked genes forming a hub of interactions involving nucleosome-depleted regions. Together, the regulatory elements coalesce with transcription factors, chromatin modifying/remodeling enzymes, coactivators, and the Mediator and/or Integrator complex into a transcription factory which may be analogous to a liquid–liquid phase-separated condensate. The broad epigenetic domain has a dynamic chromatin structure which supports frequent transcription bursts. In this review, we present the current knowledge of broad epigenetic domains.
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Affiliation(s)
- Tasnim H Beacon
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB, R3E 0V9, Canada.,Department of Biochemistry and Medical Genetics, University of Manitoba, 745 Bannatyne Avenue, Room 333A, Winnipeg, MB, Canada
| | - Geneviève P Delcuve
- Department of Biochemistry and Medical Genetics, University of Manitoba, 745 Bannatyne Avenue, Room 333A, Winnipeg, MB, Canada
| | - Camila López
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB, R3E 0V9, Canada.,Department of Biochemistry and Medical Genetics, University of Manitoba, 745 Bannatyne Avenue, Room 333A, Winnipeg, MB, Canada
| | - Gino Nardocci
- Faculty of Medicine, Universidad de Los Andes, Santiago, Chile.,Molecular Biology and Bioinformatics Lab, Program in Molecular Biology and Bioinformatics, Center for Biomedical Research and Innovation (CIIB), Universidad de Los Andes, Santiago, Chile
| | - Igor Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada
| | - Andre J van Wijnen
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA.,Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - James R Davie
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB, R3E 0V9, Canada. .,Department of Biochemistry and Medical Genetics, University of Manitoba, 745 Bannatyne Avenue, Room 333A, Winnipeg, MB, Canada.
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Cannistraro VJ, Pondugula S, Song Q, Taylor JS. Rapid deamination of cyclobutane pyrimidine dimer photoproducts at TCG sites in a translationally and rotationally positioned nucleosome in vivo. J Biol Chem 2015; 290:26597-609. [PMID: 26354431 DOI: 10.1074/jbc.m115.673301] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Indexed: 11/06/2022] Open
Abstract
Sunlight-induced C to T mutation hot spots in skin cancers occur primarily at methylated CpG sites that coincide with sites of UV-induced cyclobutane pyrimidine dimer (CPD) formation. The C and 5-methyl-C in CPDs are not stable and deaminate to U and T, respectively, which leads to the insertion of A by the DNA damage bypass polymerase η, thereby defining a probable mechanism for the origin of UV-induced C to T mutations. Deamination rates for T(m)CG CPDs have been found to vary 12-fold with rotational position in a nucleosome in vitro. To determine the influence of nucleosome structure on deamination rates in vivo, we determined the deamination rates of CPDs at TCG sites in a stably positioned nucleosome within the FOS promoter in HeLa cells. A procedure for in vivo hydroxyl radical footprinting with Fe-EDTA was developed, and, together with results from a cytosine methylation protection assay, we determined the translational and rotational positions of the TCG sites. Consistent with the in vitro observations, deamination was slower for one CPD located at an intermediate rotational position compared with two other sites located at outside positions, and all were much faster than for CPDs at non-TCG sites. Photoproduct formation was also highly suppressed at one site, possibly due to its interaction with a histone tail. Thus, it was shown that CPDs of TCG sites deaminate the fastest in vivo and that nucleosomes can modulate both their formation and deamination, which could contribute to the UV mutation hot spots and cold spots.
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Affiliation(s)
| | - Santhi Pondugula
- From the Department of Chemistry, Washington University, St. Louis, Missouri 63130
| | - Qian Song
- From the Department of Chemistry, Washington University, St. Louis, Missouri 63130
| | - John-Stephen Taylor
- From the Department of Chemistry, Washington University, St. Louis, Missouri 63130
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Integrated DNA methylation and chromatin structural analysis at single-molecule resolution. Methods Mol Biol 2015; 1288:123-41. [PMID: 25827879 DOI: 10.1007/978-1-4939-2474-5_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Chromatin limits the accessibility of DNA to trans-acting factors in transcription, replication, and repair. Although transcriptional variation between cells in a population may contribute to survival and disease, most assays of chromatin structure recover only population averages. We have developed DNA methyltransferases (MTases) as probing agents of DNA accessibility in chromatin, either expressed in vivo in budding yeast or as recombinant enzymatic probes of nuclei isolated from mammalian cells. In this chapter, we focus on the use of recombinant MTase (M) M.CviPI to probe chromatin accessibility in nuclei isolated from mammalian cell lines and animal tissue. This technique, named methylation accessibility protocol for individual templates (MAPit), reports protein-DNA interactions at single-molecule resolution. The single-molecule readout allows identification of chromatin subpopulations and rare epigenetic variants within a cell population. Furthermore, the use of M.CviPI in mammalian systems gives a comprehensive view of both chromatin structure and endogenous DNA methylation in a single assay.
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Levy-Sakin M, Grunwald A, Kim S, Gassman NR, Gottfried A, Antelman J, Kim Y, Ho S, Samuel R, Michalet X, Lin RR, Dertinger T, Kim AS, Chung S, Colyer RA, Weinhold E, Weiss S, Ebenstein Y. Toward single-molecule optical mapping of the epigenome. ACS NANO 2014; 8:14-26. [PMID: 24328256 PMCID: PMC4022788 DOI: 10.1021/nn4050694] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The past decade has seen an explosive growth in the utilization of single-molecule techniques for the study of complex systems. The ability to resolve phenomena otherwise masked by ensemble averaging has made these approaches especially attractive for the study of biological systems, where stochastic events lead to inherent inhomogeneity at the population level. The complex composition of the genome has made it an ideal system to study at the single-molecule level, and methods aimed at resolving genetic information from long, individual, genomic DNA molecules have been in use for the last 30 years. These methods, and particularly optical-based mapping of DNA, have been instrumental in highlighting genomic variation and contributed significantly to the assembly of many genomes including the human genome. Nanotechnology and nanoscopy have been a strong driving force for advancing genomic mapping approaches, allowing both better manipulation of DNA on the nanoscale and enhanced optical resolving power for analysis of genomic information. During the past few years, these developments have been adopted also for epigenetic studies. The common principle for these studies is the use of advanced optical microscopy for the detection of fluorescently labeled epigenetic marks on long, extended DNA molecules. Here we will discuss recent single-molecule studies for the mapping of chromatin composition and epigenetic DNA modifications, such as DNA methylation.
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Affiliation(s)
- Michal Levy-Sakin
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv, Israel
| | - Assaf Grunwald
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv, Israel
| | - Soohong Kim
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Natalie R. Gassman
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Anna Gottfried
- Institute of Organic Chemistry, RWTH Aachen University, Aachen, Germany
| | - Josh Antelman
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Younggyu Kim
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Sam Ho
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Robin Samuel
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Xavier Michalet
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Ron R. Lin
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Thomas Dertinger
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Andrew S. Kim
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Sangyoon Chung
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Ryan A. Colyer
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Elmar Weinhold
- Institute of Organic Chemistry, RWTH Aachen University, Aachen, Germany
| | - Shimon Weiss
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
- Corresponding authors: (Y. Ebenstein), (S. Weiss)
| | - Yuval Ebenstein
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv, Israel
- Corresponding authors: (Y. Ebenstein), (S. Weiss)
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James SR, Cedeno CD, Sharma A, Zhang W, Mohler JL, Odunsi K, Wilson EM, Karpf AR. DNA methylation and nucleosome occupancy regulate the cancer germline antigen gene MAGEA11. Epigenetics 2013; 8:849-63. [PMID: 23839233 DOI: 10.4161/epi.25500] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
MAGEA11 is a cancer germline (CG) antigen and androgen receptor co-activator. Its expression in cancers other than prostate, and its mechanism of activation, has not been reported. In silico analyses reveal that MAGEA11 is frequently expressed in human cancers, is increased during tumor progression, and correlates with poor prognosis and survival. In prostate and epithelial ovarian cancers (EOC), MAGEA11 expression was associated with promoter and global DNA hypomethylation, and with activation of other CG genes. Pharmacological or genetic inhibition of DNA methyltransferases (DNMTs) and/or histone deacetylases (HDACs) activated MAGEA11 in a cell line specific manner. MAGEA11 promoter activity was directly repressed by DNA methylation, and partially depended on Sp1, as pharmacological or genetic targeting of Sp1 reduced MAGEA11 promoter activity and endogenous gene expression. Importantly, DNA methylation regulated nucleosome occupancy specifically at the -1 positioned nucleosome of MAGEA11. Methylation of a single Ets site near the transcriptional start site (TSS) correlated with -1 nucleosome occupancy and, by itself, strongly repressed MAGEA11 promoter activity. Thus, DNA methylation regulates nucleosome occupancy at MAGEA11, and this appears to function cooperatively with sequence-specific transcription factors to regulate gene expression. MAGEA11 regulation is highly instructive for understanding mechanisms regulating CG antigen genes in human cancer.
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Affiliation(s)
- Smitha R James
- Department of Pharmacology and Therapeutics; Roswell Park Cancer Institute; Buffalo, NY USA
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Darst RP, Haecker I, Pardo CE, Renne R, Kladde MP. Epigenetic diversity of Kaposi's sarcoma-associated herpesvirus. Nucleic Acids Res 2013; 41:2993-3009. [PMID: 23361465 PMCID: PMC3597696 DOI: 10.1093/nar/gkt033] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Spontaneous lytic reactivation of Kaposi’s sarcoma–associated herpesvirus (KSHV) occurs at a low rate in latently infected cells in disease and culture. This suggests imperfect epigenetic maintenance of viral transcription programs, perhaps due to variability in chromatin structure at specific loci across the population of KSHV episomal genomes. To characterize this locus-specific chromatin structural diversity, we used MAPit single-molecule footprinting, which simultaneously maps endogenous CG methylation and accessibility to M.CviPI at GC sites. Diverse chromatin structures were detected at the LANA, RTA and vIL6 promoters. At each locus, chromatin ranged from fully closed to fully open across the population. This diversity has not previously been reported in a virus. Phorbol ester and RTA transgene induction were used to identify chromatin conformations associated with reactivation of lytic transcription, which only a fraction of episomes had. Moreover, certain chromatin conformations correlated with CG methylation patterns at the RTA and vIL6 promoters. This indicated that some of the diverse chromatin conformations at these loci were epigenetically distinct. Finally, by comparing chromatin structures from a cell line infected with constitutively latent virus, we identified products of lytic replication. Our findings show that epigenetic drift can restrict viral propagation by chromatin compaction at latent and lytic promoters.
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Affiliation(s)
- Russell P Darst
- Department of Biochemistry and Molecular Biology, 2033 Mowry Road, Box 103633, University of Florida College of Medicine, Gainesville, FL, 32610, USA
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Santostefano KE, Hamazaki T, Pardo CE, Kladde MP, Terada N. Fibroblast growth factor receptor 2 homodimerization rapidly reduces transcription of the pluripotency gene Nanog without dissociation of activating transcription factors. J Biol Chem 2012; 287:30507-17. [PMID: 22787153 DOI: 10.1074/jbc.m112.388181] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Nanog or Gata6-positive cells co-exist and are convertible within the inner cell mass of murine blastocysts and embryonic stem (ES) cells. Previous studies demonstrate fibroblast growth factor receptor 2 (FGFR2) triggers Nanog gene down-regulation and differentiation to primitive endoderm (PE); however, the underlying mechanisms responsible for reversible and fluctuating cell fate are poorly understood. Using an inducible FGFR2 dimerization system in ES cells, we demonstrate that FGFR2 activation rapidly down-regulated Nanog gene transcription through activation of the Mek pathway and subsequently differentiated ES cells into PE cells. FGFR2 rather selectively repressed the Nanog gene with minimal effect on other pluripotency genes, including Oct4 and Sox2. We determined the Nanog promoter region containing minimum Oct4/Sox2 binding sites was sufficient for this transcriptional down-regulation by FGFR2, when the reporter transgenes were integrated with insulators. Of interest, FGFR2-mediated Nanog transcriptional reduction occurred without dissociation of RNA polymerase II, p300, Oct4, Sox2, and Tet1 from the Nanog proximal promoter region and with no increase in repressive histone methylation marks or DNA methylation, implying the gene repression is in the early and transient phase. Furthermore, addition of a specific FGFR inhibitor readily reversed this Nanog repression status. These findings illustrate well how FGFR2 induces rapid but reversible Nanog repression within ES cells.
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Darst RP, Nabilsi NH, Pardo CE, Riva A, Kladde MP. DNA methyltransferase accessibility protocol for individual templates by deep sequencing. Methods Enzymol 2012; 513:185-204. [PMID: 22929770 DOI: 10.1016/b978-0-12-391938-0.00008-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
A single-molecule probe of chromatin structure can uncover dynamic chromatin states and rare epigenetic variants of biological importance that bulk measures of chromatin structure miss. In bisulfite genomic sequencing, each sequenced clone records the methylation status of multiple sites on an individual molecule of DNA. An exogenous DNA methyltransferase can thus be used to image nucleosomes and other protein-DNA complexes. In this chapter, we describe the adaptation of this technique, termed Methylation Accessibility Protocol for individual templates, to modern high-throughput sequencing, which both simplifies the workflow and extends its utility.
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Affiliation(s)
- Russell P Darst
- Department of Biochemistry and Molecular Biology, University of Florida Shands Cancer Center Program in Cancer Genetics, Epigenetics, and Tumor Virology, Gainesville, Florida, USA
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