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Chanou A, Hamperl S. Single-Molecule Techniques to Study Chromatin. Front Cell Dev Biol 2021; 9:699771. [PMID: 34291054 PMCID: PMC8287188 DOI: 10.3389/fcell.2021.699771] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 05/26/2021] [Indexed: 12/14/2022] Open
Abstract
Besides the basic organization in nucleosome core particles (NCPs), eukaryotic chromatin is further packed through interactions with numerous protein complexes including transcription factors, chromatin remodeling and modifying enzymes. This nucleoprotein complex provides the template for many important biological processes, such as DNA replication, transcription, and DNA repair. Thus, to understand the molecular basis of these DNA transactions, it is critical to define individual changes of the chromatin structure at precise genomic regions where these machineries assemble and drive biological reactions. Single-molecule approaches provide the only possible solution to overcome the heterogenous nature of chromatin and monitor the behavior of individual chromatin transactions in real-time. In this review, we will give an overview of currently available single-molecule methods to obtain mechanistic insights into nucleosome positioning, histone modifications and DNA replication and transcription analysis-previously unattainable with population-based assays.
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Affiliation(s)
| | - Stephan Hamperl
- Chromosome Dynamics and Genome Stability, Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, Munich, Germany
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2
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Pott S. Simultaneous measurement of chromatin accessibility, DNA methylation, and nucleosome phasing in single cells. eLife 2017; 6:e23203. [PMID: 28653622 PMCID: PMC5487215 DOI: 10.7554/elife.23203] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 05/26/2017] [Indexed: 12/23/2022] Open
Abstract
Gaining insights into the regulatory mechanisms that underlie the transcriptional variation observed between individual cells necessitates the development of methods that measure chromatin organization in single cells. Here I adapted Nucleosome Occupancy and Methylome-sequencing (NOMe-seq) to measure chromatin accessibility and endogenous DNA methylation in single cells (scNOMe-seq). scNOMe-seq recovered characteristic accessibility and DNA methylation patterns at DNase hypersensitive sites (DHSs). An advantage of scNOMe-seq is that sequencing reads are sampled independently of the accessibility measurement. scNOMe-seq therefore controlled for fragment loss, which enabled direct estimation of the fraction of accessible DHSs within individual cells. In addition, scNOMe-seq provided high resolution of chromatin accessibility within individual loci which was exploited to detect footprints of CTCF binding events and to estimate the average nucleosome phasing distances in single cells. scNOMe-seq is therefore well-suited to characterize the chromatin organization of single cells in heterogeneous cellular mixtures.
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Affiliation(s)
- Sebastian Pott
- Department of Human Genetics, University of Chicago, Chicago, United States
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3
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Halby L, Menon Y, Rilova E, Pechalrieu D, Masson V, Faux C, Bouhlel MA, David-Cordonnier MH, Novosad N, Aussagues Y, Samson A, Lacroix L, Ausseil F, Fleury L, Guianvarc'h D, Ferroud C, Arimondo PB. Rational Design of Bisubstrate-Type Analogues as Inhibitors of DNA Methyltransferases in Cancer Cells. J Med Chem 2017; 60:4665-4679. [PMID: 28463515 DOI: 10.1021/acs.jmedchem.7b00176] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Aberrant DNA hypermethylation of promoter of tumor suppressor genes is commonly observed in cancer, and its inhibition by small molecules is promising for their reactivation. Here we designed bisubstrate analogues-based inhibitors, by mimicking each substrate, the S-adenosyl-l-methionine and the deoxycytidine, and linking them together. This approach resulted in quinazoline-quinoline derivatives as potent inhibitors of DNMT3A and DNMT1, some showing certain isoform selectivity. We highlighted the importance of (i) the nature and rigidity of the linker between the two moieties for inhibition, as (ii) the presence of the nitrogen on the quinoline group, and (iii) of a hydrophobic group on the quinazoline. The most potent inhibitors induced demethylation of CDKN2A promoter in colon carcinoma HCT116 cells and its reactivation after 7 days of treatment. Furthermore, in a leukemia cell model system, we found a correlation between demethylation of the promoter induced by the treatment, chromatin opening at the promoter, and the reactivation of a reporter gene.
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Affiliation(s)
- Ludovic Halby
- ETaC, Epigenetic Targeting of Cancer, CRDPF, CNRS-Pierre Fabre USR3388 , 3 Avenue H. Curien, 31035 Toulouse cedex 01, France
| | - Yoann Menon
- ETaC, Epigenetic Targeting of Cancer, CRDPF, CNRS-Pierre Fabre USR3388 , 3 Avenue H. Curien, 31035 Toulouse cedex 01, France
| | - Elodie Rilova
- ETaC, Epigenetic Targeting of Cancer, CRDPF, CNRS-Pierre Fabre USR3388 , 3 Avenue H. Curien, 31035 Toulouse cedex 01, France
| | - Dany Pechalrieu
- ETaC, Epigenetic Targeting of Cancer, CRDPF, CNRS-Pierre Fabre USR3388 , 3 Avenue H. Curien, 31035 Toulouse cedex 01, France
| | - Véronique Masson
- ETaC, Epigenetic Targeting of Cancer, CRDPF, CNRS-Pierre Fabre USR3388 , 3 Avenue H. Curien, 31035 Toulouse cedex 01, France
| | - Celine Faux
- ETaC, Epigenetic Targeting of Cancer, CRDPF, CNRS-Pierre Fabre USR3388 , 3 Avenue H. Curien, 31035 Toulouse cedex 01, France
| | - Mohamed Amine Bouhlel
- UMR-S1172-JPARC (Jean-Pierre Aubert Research Center), INSERM, University of Lille, Centre Hospitalier Universitaire de Lille, IRCL , 59045 Lille, France
| | - Marie-Hélène David-Cordonnier
- UMR-S1172-JPARC (Jean-Pierre Aubert Research Center), INSERM, University of Lille, Centre Hospitalier Universitaire de Lille, IRCL , 59045 Lille, France
| | - Natacha Novosad
- ETaC, Epigenetic Targeting of Cancer, CRDPF, CNRS-Pierre Fabre USR3388 , 3 Avenue H. Curien, 31035 Toulouse cedex 01, France
| | - Yannick Aussagues
- ETaC, Epigenetic Targeting of Cancer, CRDPF, CNRS-Pierre Fabre USR3388 , 3 Avenue H. Curien, 31035 Toulouse cedex 01, France
| | - Arnaud Samson
- ETaC, Epigenetic Targeting of Cancer, CRDPF, CNRS-Pierre Fabre USR3388 , 3 Avenue H. Curien, 31035 Toulouse cedex 01, France
| | | | - Fréderic Ausseil
- ETaC, Epigenetic Targeting of Cancer, CRDPF, CNRS-Pierre Fabre USR3388 , 3 Avenue H. Curien, 31035 Toulouse cedex 01, France
| | - Laurence Fleury
- ETaC, Epigenetic Targeting of Cancer, CRDPF, CNRS-Pierre Fabre USR3388 , 3 Avenue H. Curien, 31035 Toulouse cedex 01, France
| | - Dominique Guianvarc'h
- Laboratoire des BioMolécules, UMR 7203, Université Pierre et Marie Curie-Paris 6-ENS-CNRS , 4, place Jussieu, 75252 Paris Cedex 05, France
| | - Clotilde Ferroud
- Laboratoire de Chimie Moléculaire, CMGPCE, EA7341, Conservatoire National des Arts et Métiers , 2 rue Conté, 75003 Paris, France
| | - Paola B Arimondo
- ETaC, Epigenetic Targeting of Cancer, CRDPF, CNRS-Pierre Fabre USR3388 , 3 Avenue H. Curien, 31035 Toulouse cedex 01, France.,Churchill College , CB3 0DS Cambridge, U.K
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4
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de Conti A, Kobets T, Tryndyak V, Burnett SD, Han T, Fuscoe JC, Beland FA, Doerge DR, Pogribny IP. Persistence of furan-induced epigenetic aberrations in the livers of F344 rats. Toxicol Sci 2015; 144:217-26. [PMID: 25539665 PMCID: PMC4372661 DOI: 10.1093/toxsci/kfu313] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Furan is a heterocyclic organic compound produced in the chemical manufacturing industry and also found in a broad range of food products, including infant formulas and baby foods. Previous reports have indicated that the adverse biological effects of furan, including its liver tumorigenicity, may be associated with epigenetic abnormalities. In the present study, we investigated the persistence of epigenetic alterations in rat liver. Male F344 rats were treated by gavage 5 days per week with 8 mg furan/kg body weight (bw)/day for 90 days. After the last treatment, rats were divided randomly into 4 groups; 1 group of rats was sacrificed 24 h after the last treatment, whereas other groups were maintained without further furan treatment for an additional 90, 180, or 360 days. Treatment with furan for 90 days resulted in alterations in histone lysine methylation and acetylation, induction of base-excision DNA repair genes, suggesting oxidative damage to DNA, and changes in the gene expression in the livers. A majority of these furan-induced molecular changes was transient and disappeared after the cessation of furan treatment. In contrast, histone H3 lysine 9 and H3 lysine 56 showed a sustained and time-depended decrease in acetylation, which was associated with formation of heterochromatin and altered gene expression. These results indicate that furan-induced adverse effects may be mechanistically related to sustained changes in histone lysine acetylation that compromise the ability of cells to maintain and control properly the expression of genetic information.
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Affiliation(s)
- Aline de Conti
- *Division of Biochemical Toxicology and Division of Systems Biology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Tetyana Kobets
- *Division of Biochemical Toxicology and Division of Systems Biology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Volodymyr Tryndyak
- *Division of Biochemical Toxicology and Division of Systems Biology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Sarah D Burnett
- *Division of Biochemical Toxicology and Division of Systems Biology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Tao Han
- *Division of Biochemical Toxicology and Division of Systems Biology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - James C Fuscoe
- *Division of Biochemical Toxicology and Division of Systems Biology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Frederick A Beland
- *Division of Biochemical Toxicology and Division of Systems Biology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Daniel R Doerge
- *Division of Biochemical Toxicology and Division of Systems Biology, National Center for Toxicological Research, Jefferson, Arkansas 72079
| | - Igor P Pogribny
- *Division of Biochemical Toxicology and Division of Systems Biology, National Center for Toxicological Research, Jefferson, Arkansas 72079
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5
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Yamamoto S, De D, Hidaka K, Kim KK, Endo M, Sugiyama H. Single molecule visualization and characterization of Sox2-Pax6 complex formation on a regulatory DNA element using a DNA origami frame. NANO LETTERS 2014; 14:2286-2292. [PMID: 24660747 DOI: 10.1021/nl4044949] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report the use of atomic force microscopy (AFM) to study Sox2-Pax6 complex formation on the regulatory DNA element at a single molecule level. Using an origami DNA scaffold containing two DNA strands with different levels of tensile force, we confirmed that DNA bending is necessary for Sox2 binding. We also demonstrated that two transcription factors bind cooperatively by observing the increased occupancy of Sox2-Pax6 on the DNA element compared to that of Sox2 alone.
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Affiliation(s)
- Seigi Yamamoto
- Department of Chemistry, Graduate School of Science, Kyoto University , Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
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6
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Dai S, Feng C, Li W, Jiang W, Wang L. Quantitative detection of tumor necrosis factor-α by single molecule counting based on a hybridization chain reaction. Biosens Bioelectron 2014; 60:180-4. [PMID: 24800682 DOI: 10.1016/j.bios.2014.04.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/26/2014] [Accepted: 04/07/2014] [Indexed: 02/09/2023]
Abstract
This work reports a novel and sensitive quantitative method for detection of tumor necrosis factor-α (TNF-α) based on single molecule counting and hybridization chain reaction (HCR). In the presence of TNF-α, sandwich-type immunocomplex was formed on the surface of glass substrate. The streptavidin acted as a bridge bounded to the biotinylated immunocomplex, which provided three sites to fixate the biotinylated initiator strands. The initiator strands triggered the chain reaction of hybridization to form a long double-helix polymer and SYBR Green I, acted as the fluorescence label, intercalated into the grooves of the long dsDNA polymer. Then, the quantitative detection of TNF-α was realized by single molecule counting. Under the optimal conditions, HCR-based single molecule counting quantitative method could successfully detect TNF-α in the range of 50 fM to 1 pM, and it revealed a reliable result for TNF-α detection in real serum. Moreover, the proposed immunosensor exhibited excellent specificity. These results greatly demonstrated that the proposed method possessed the potentiality in clinical application and it was suitable for quantification of biomarker under low concentration.
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Affiliation(s)
- Shuang Dai
- Key Laboratory of Natural Products Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, 250012 Jinan, PR China
| | - Chunjing Feng
- Key Laboratory of Natural Products Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, 250012 Jinan, PR China
| | - Wei Li
- Key Laboratory of Natural Products Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, 250012 Jinan, PR China
| | - Wei Jiang
- School of Chemistry and Chemical Engineering, Shandong University, 250100 Jinan, PR China.
| | - Lei Wang
- Key Laboratory of Natural Products Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, 250012 Jinan, PR China.
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7
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Jeong KW, Andreu-Vieyra C, You JS, Jones PA, Stallcup MR. Establishment of active chromatin structure at enhancer elements by mixed-lineage leukemia 1 to initiate estrogen-dependent gene expression. Nucleic Acids Res 2013; 42:2245-56. [PMID: 24288367 PMCID: PMC3936730 DOI: 10.1093/nar/gkt1236] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A number of genome-wide analyses have revealed that estrogen receptor α binding to and regulation of its target genes correlate with binding of FOXA1, a pioneer factor, to nearby DNA sites in MCF-7 breast cancer cells. The enhancer element-specific histone H3K4me1/2 mark is enriched at the specific FOXA1/ERα recruitment sites in chromatin, but the mechanism by which these enhancer marks are established in chromatin before hormone treatment is unclear. Here, we show that mixed-lineage leukemia 1 (MLL1) protein is a key determinant that maintains permissive chromatin structure of the TFF1 enhancer region. MLL1 occupies the TFF1 enhancer region and methylates H3K4 before hormone stimulation. In vitro, MLL1 binds directly to the CpG-rich region of the TFF1 enhancer, and its binding is dependent on hypomethylation of DNA. Furthermore, the depletion of MLL1 in MCF-7 cells results in a dramatic decrease of chromatin accessibility and recruitment of FOXA1 and ERα to the enhancer element. Our study defines the mechanism by which MLL1 nucleates histone H3K4 methylation marks in CpG-enriched regions to maintain permissive chromatin architecture and allow FOXA1 and estrogen receptor α binding to transcriptional regulatory sites in breast cancer cells.
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Affiliation(s)
- Kwang Won Jeong
- Gachon Institute of Pharmaceutical Sciences, College of Pharmacy, Gachon University, Incheon 406-840, Republic of Korea, Departments of Urology and Biochemistry and Molecular Biology, USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089-9176, USA, Department of Biochemistry, School of Medicine, Konkuk University, Seoul 143-701, Republic of Korea and Department of Biochemistry and Molecular Biology, USC/Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089-9176, USA
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8
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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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9
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Kelly TK, Liu Y, Lay FD, Liang G, Berman BP, Jones PA. Genome-wide mapping of nucleosome positioning and DNA methylation within individual DNA molecules. Genome Res 2012; 22:2497-506. [PMID: 22960375 PMCID: PMC3514679 DOI: 10.1101/gr.143008.112] [Citation(s) in RCA: 308] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
DNA methylation and nucleosome positioning work together to generate chromatin structures that regulate gene expression. Nucleosomes are typically mapped using nuclease digestion requiring significant amounts of material and varying enzyme concentrations. We have developed a method (NOMe-seq) that uses a GpC methyltransferase (M.CviPI) and next generation sequencing to generate a high resolution footprint of nucleosome positioning genome-wide using less than 1 million cells while retaining endogenous DNA methylation information from the same DNA strand. Using a novel bioinformatics pipeline, we show a striking anti-correlation between nucleosome occupancy and DNA methylation at CTCF regions that is not present at promoters. We further show that the extent of nucleosome depletion at promoters is directly correlated to expression level and can accommodate multiple nucleosomes and provide genome-wide evidence that expressed non-CpG island promoters are nucleosome-depleted. Importantly, NOMe-seq obtains DNA methylation and nucleosome positioning information from the same DNA molecule, giving the first genome-wide DNA methylation and nucleosome positioning correlation at the single molecule, and thus, single cell level, that can be used to monitor disease progression and response to therapy.
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Affiliation(s)
- Theresa K Kelly
- Department of Urology, Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
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10
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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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Rajendran A, Endo M, Sugiyama H. Single-molecule analysis using DNA origami. Angew Chem Int Ed Engl 2011; 51:874-90. [PMID: 22121063 DOI: 10.1002/anie.201102113] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Indexed: 11/11/2022]
Abstract
During the last two decades, scientists have developed various methods that allow the detection and manipulation of single molecules, which have also been called "in singulo" approaches. Fundamental understanding of biochemical reactions, folding of biomolecules, and the screening of drugs were achieved by using these methods. Single-molecule analysis was also performed in the field of DNA nanotechnology, mainly by using atomic force microscopy. However, until recently, the approaches used commonly in nanotechnology adopted structures with a dimension of 10-20 nm, which is not suitable for many applications. The recent development of scaffolded DNA origami by Rothemund made it possible for the construction of larger defined assemblies. One of the most salient features of the origami method is the precise addressability of the structures formed: Each staple can serve as an attachment point for different kinds of nanoobjects. Thus, the method is suitable for the precise positioning of various functionalities and for the single-molecule analysis of many chemical and biochemical processes. Here we summarize recent progress in the area of single-molecule analysis using DNA origami and discuss the future directions of this research.
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Affiliation(s)
- Arivazhagan Rajendran
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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12
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Rajendran A, Endo M, Sugiyama H. Einzelmolekülanalysen mithilfe von DNA-Origami. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201102113] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Dynamic nucleosome-depleted regions at androgen receptor enhancers in the absence of ligand in prostate cancer cells. Mol Cell Biol 2011; 31:4648-62. [PMID: 21969603 DOI: 10.1128/mcb.05934-11] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nucleosome positioning at transcription start sites is known to regulate gene expression by altering DNA accessibility to transcription factors; however, its role at enhancers is poorly understood. We investigated nucleosome positioning at the androgen receptor (AR) enhancers of TMPRSS2, KLK2, and KLK3/PSA in prostate cancer cells. Surprisingly, a population of enhancer modules in androgen-deprived cultures showed nucleosome-depleted regions (NDRs) in all three loci. Under androgen-deprived conditions, NDRs at the TMPRSS2 enhancer were maintained by the pioneer AR transcriptional collaborator GATA-2. Androgen treatment resulted in AR occupancy, an increased number of enhancer modules with NDRs without changes in footprint width, increased levels of histone H3 acetylation (AcH3), and dimethylation (H3K4me2) at nucleosomes flanking the NDRs. Our data suggest that, in the absence of ligand, AR enhancers exist in an equilibrium in which a percentage of modules are occupied by nucleosomes while others display NDRs. We propose that androgen treatment leads to the disruption of the equilibrium toward a nucleosome-depleted state, rather than to enhancer de novo "remodeling." This allows the recruitment of histone modifiers, chromatin remodelers, and ultimately gene activation. The "receptive" state described here could help explain AR signaling activation under very low ligand concentrations.
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14
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Koturbash I, Scherhag A, Sorrentino J, Sexton K, Bodnar W, Swenberg JA, Beland FA, Pardo-Manuel deVillena F, Rusyn I, Pogribny IP. Epigenetic mechanisms of mouse interstrain variability in genotoxicity of the environmental toxicant 1,3-butadiene. Toxicol Sci 2011; 122:448-56. [PMID: 21602187 PMCID: PMC3155089 DOI: 10.1093/toxsci/kfr133] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 05/11/2011] [Indexed: 12/18/2022] Open
Abstract
1,3-Butadiene (BD) is a common environmental contaminant classified as "carcinogenic to humans." Formation of BD-induced DNA adducts plays a major role in its carcinogenicity. BD is also an epigenotoxic agent (i.e., it affects DNA and histone methylation in the liver). We used a panel of genetically diverse inbred mice (NOD/LtJ, CAST/EiJ, A/J, WSB/EiJ, PWK/PhJ, C57BL/6J, and 129S1/SvImJ) to assess whether BD-induced genotoxic and epigenotoxic events may be subject to interstrain differences. Mice (male, 7 weeks) were exposed via inhalation to 0 or 625 ppm BD for 6 h/day and 5 days/week for 2 weeks and liver BD-DNA adducts, epigenetic alterations, and liver toxicity were assessed. N-7-(2,3,4-trihydroxybut-1-yl)-guanine adducts were detected in all strains after exposure, yet BD-induced DNA damage in CAST/EiJ mice was two to three times lower. Epigenetic effects of BD were most prominent in C57BL/6J mice where loss of global DNA methylation and loss of trimethylation of histone H3 lysine 9, histone H3 lysine 27, and histone H4 lysine 20, accompanied by dysregulation of liver gene expression indicative of hepatotoxicity, were found. Interestingly, we observed an increase in histone methylation in the absence of changes in gene expression and DNA methylation in CAST/EiJ strain. We hypothesized that mitigated genotoxicity of BD in CAST/EiJ mice may be due to chromatin condensation. Indeed, we show that in response to BD exposure, chromatin condensation occurs in CAST/EiJ, whereas the opposite effect is observed in C57BL/6J mice. These findings demonstrate that interstrain susceptibility to genotoxicity by a well-known environmental carcinogen may be due to strain-specific epigenetic events in response to the exposure.
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Affiliation(s)
- Igor Koturbash
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079
| | - Anne Scherhag
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079
- Technical University of Kaiserslautern, Kaiserslautern, Rheinland-Pfalz 67663, Germany
| | | | | | - Wanda Bodnar
- Department of Environmental Sciences and Engineering
| | - James A. Swenberg
- Curriculum in Toxicology
- Department of Environmental Sciences and Engineering
| | - Frederick A. Beland
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079
| | | | - Ivan Rusyn
- Curriculum in Toxicology
- Department of Environmental Sciences and Engineering
| | - Igor P. Pogribny
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079
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15
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Kelly TK, Miranda TB, Liang G, Berman BP, Lin JC, Tanay A, Jones PA. H2A.Z maintenance during mitosis reveals nucleosome shifting on mitotically silenced genes. Mol Cell 2010; 39:901-11. [PMID: 20864037 PMCID: PMC2947862 DOI: 10.1016/j.molcel.2010.08.026] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Revised: 05/26/2010] [Accepted: 07/06/2010] [Indexed: 11/16/2022]
Abstract
Profound chromatin changes occur during mitosis to allow for gene silencing and chromosome segregation followed by reactivation of memorized transcription states in daughter cells. Using genome-wide sequencing, we found H2A.Z-containing +1 nucleosomes of active genes shift upstream to occupy TSSs during mitosis, significantly reducing nucleosome-depleted regions. Single-molecule analysis confirmed nucleosome shifting and demonstrated that mitotic shifting is specific to active genes that are silenced during mitosis and, thus, is not seen on promoters, which are silenced by methylation or mitotically expressed genes. Using the GRP78 promoter as a model, we found H3K4 trimethylation is also maintained while other indicators of active chromatin are lost and expression is decreased. These key changes provide a potential mechanism for rapid silencing and reactivation of genes during the cell cycle.
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Affiliation(s)
- Theresa K. Kelly
- Departments of Urology and Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Tina Branscombe Miranda
- Departments of Urology and Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Gangning Liang
- Departments of Urology and Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Benjamin P. Berman
- USC Epigenome Center, University of Southern California, Los Angeles, CA USA
| | - Joy C. Lin
- Departments of Urology and Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Amos Tanay
- Department of Computer Science and Applied Mathematics, The Weizmann Institute, Rehovot, Israel
| | - Peter A. Jones
- Departments of Urology and Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
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