1
|
Ayaz G, Turan G, Olgun ÇE, Kars G, Karakaya B, Yavuz K, Demiralay ÖD, Can T, Muyan M, Yaşar P. A prelude to the proximity interaction mapping of CXXC5. Sci Rep 2021; 11:17587. [PMID: 34475492 PMCID: PMC8413330 DOI: 10.1038/s41598-021-97060-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 08/17/2021] [Indexed: 11/09/2022] Open
Abstract
CXXC5 is a member of the zinc-finger CXXC family proteins that interact with unmodified CpG dinucleotides through a conserved ZF-CXXC domain. CXXC5 is involved in the modulation of gene expressions that lead to alterations in diverse cellular events. However, the underlying mechanism of CXXC5-modulated gene expressions remains unclear. Proteins perform their functions in a network of proteins whose identities and amounts change spatiotemporally in response to various stimuli in a lineage-specific manner. Since CXXC5 lacks an intrinsic transcription regulatory function or enzymatic activity but is a DNA binder, CXXC5 by interacting with proteins could act as a scaffold to establish a chromatin state restrictive or permissive for transcription. To initially address this, we utilized the proximity-dependent biotinylation approach. Proximity interaction partners of CXXC5 include DNA and chromatin modifiers, transcription factors/co-regulators, and RNA processors. Of these, CXXC5 through its CXXC domain interacted with EMD, MAZ, and MeCP2. Furthermore, an interplay between CXXC5 and MeCP2 was critical for a subset of CXXC5 target gene expressions. It appears that CXXC5 may act as a nucleation factor in modulating gene expressions. Providing a prelude for CXXC5 actions, our results could also contribute to a better understanding of CXXC5-mediated cellular processes in physiology and pathophysiology.
Collapse
Affiliation(s)
- Gamze Ayaz
- Department of Biological Sciences, Middle East Technical University, 06800, Ankara, Turkey. .,Cancer and Stem Cell Epigenetics Section, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Gizem Turan
- Department of Biological Sciences, Middle East Technical University, 06800, Ankara, Turkey
| | - Çağla Ece Olgun
- Department of Biological Sciences, Middle East Technical University, 06800, Ankara, Turkey
| | - Gizem Kars
- Department of Biological Sciences, Middle East Technical University, 06800, Ankara, Turkey
| | - Burcu Karakaya
- Department of Biological Sciences, Middle East Technical University, 06800, Ankara, Turkey
| | - Kerim Yavuz
- Department of Biological Sciences, Middle East Technical University, 06800, Ankara, Turkey
| | - Öykü Deniz Demiralay
- Department of Biological Sciences, Middle East Technical University, 06800, Ankara, Turkey
| | - Tolga Can
- Department of Computer Engineering Middle, East Technical University, 06800, Ankara, Turkey
| | - Mesut Muyan
- Department of Biological Sciences, Middle East Technical University, 06800, Ankara, Turkey. .,Cansyl Laboratories, Middle East Technical University, 06800, Ankara, Turkey.
| | - Pelin Yaşar
- Department of Biological Sciences, Middle East Technical University, 06800, Ankara, Turkey.,Epigenetics and Stem Cell Biology Laboratory, Single Cell Dynamics Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA
| |
Collapse
|
2
|
Yaşar P, Kars G, Yavuz K, Ayaz G, Oğuztüzün Ç, Bilgen E, Suvacı Z, Çetinkol ÖP, Can T, Muyan M. A CpG island promoter drives the CXXC5 gene expression. Sci Rep 2021; 11:15655. [PMID: 34341443 PMCID: PMC8329181 DOI: 10.1038/s41598-021-95165-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/16/2021] [Indexed: 02/06/2023] Open
Abstract
CXXC5 is a member of the zinc-finger CXXC family that binds to unmethylated CpG dinucleotides. CXXC5 modulates gene expressions resulting in diverse cellular events mediated by distinct signaling pathways. However, the mechanism responsible for CXXC5 expression remains largely unknown. We found here that of the 14 annotated CXXC5 transcripts with distinct 5' untranslated regions encoding the same protein, transcript variant 2 with the highest expression level among variants represents the main transcript in cell models. The DNA segment in and at the immediate 5'-sequences of the first exon of variant 2 contains a core promoter within which multiple transcription start sites are present. Residing in a region with high G-C nucleotide content and CpG repeats, the core promoter is unmethylated, deficient in nucleosomes, and associated with active RNA polymerase-II. These findings suggest that a CpG island promoter drives CXXC5 expression. Promoter pull-down revealed the association of various transcription factors (TFs) and transcription co-regulatory proteins, as well as proteins involved in histone/chromatin, DNA, and RNA processing with the core promoter. Of the TFs, we verified that ELF1 and MAZ contribute to CXXC5 expression. Moreover, the first exon of variant 2 may contain a G-quadruplex forming region that could modulate CXXC5 expression.
Collapse
Affiliation(s)
- Pelin Yaşar
- Department of Biological Sciences, Middle East Technical University, Ankara, 06800, Turkey.
- Epigenetics and Stem Cell Biology Laboratory, Single Cell Dynamics Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA.
| | - Gizem Kars
- Department of Biological Sciences, Middle East Technical University, Ankara, 06800, Turkey
| | - Kerim Yavuz
- Department of Biological Sciences, Middle East Technical University, Ankara, 06800, Turkey
| | - Gamze Ayaz
- Department of Biological Sciences, Middle East Technical University, Ankara, 06800, Turkey
- Cancer and Stem Cell Epigenetics Section, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Çerağ Oğuztüzün
- Department of Computer Engineering, Bilkent University, Ankara, 06800, Turkey
| | - Ecenaz Bilgen
- Department of Chemistry, Middle East Technical University, Ankara, 06800, Turkey
| | - Zeynep Suvacı
- Department of Chemistry, Middle East Technical University, Ankara, 06800, Turkey
| | | | - Tolga Can
- Department of Computer Engineering, Middle East Technical University, Ankara, 06800, Turkey
| | - Mesut Muyan
- Department of Biological Sciences, Middle East Technical University, Ankara, 06800, Turkey.
- Cansyl Laboratories, Middle East Technical University, Ankara, 06800, Turkey.
| |
Collapse
|
3
|
Knight P, Gauthier MPL, Pardo CE, Darst RP, Kapadia K, Browder H, Morton E, Riva A, Kladde MP, Bacher R. Methylscaper: an R/shiny app for joint visualization of DNA methylation and nucleosome occupancy in single-molecule and single-cell data. Bioinformatics 2021; 37:4857-4859. [PMID: 34125875 PMCID: PMC8665741 DOI: 10.1093/bioinformatics/btab438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 04/19/2021] [Accepted: 06/11/2021] [Indexed: 11/13/2022] Open
Abstract
SUMMARY Differential DNA methylation and chromatin accessibility are associated with disease development, particularly cancer. Methods that allow profiling of these epigenetic mechanisms in the same reaction and at the single-molecule or single-cell level continue to emerge. However, a challenge lies in jointly visualizing and analyzing the heterogeneous nature of the data and extracting regulatory insight. Here, we present methylscaper, a visualization framework for simultaneous analysis of DNA methylation and chromatin accessibility landscapes. Methylscaper implements a weighted principal component analysis that orders DNA molecules, each providing a record of the chromatin state of one epiallele, and reveals patterns of nucleosome positioning, transcription factor occupancy, and DNA methylation. We demonstrate methylscaper's utility on a long-read, single-molecule methyltransferase accessibility protocol for individual templates (MAPit-BGS) dataset and a single-cell nucleosome, methylation, and transcription sequencing (scNMT-seq) dataset. In comparison to other procedures, methylscaper is able to readily identify chromatin features that are biologically relevant to transcriptional status while scaling to larger datasets. AVAILABILITY AND IMPLEMENTATION Methylscaper, is implemented in R (version > 4.1) and available on Bioconductor: https://bioconductor.org/packages/methylscaper/, GitHub: https://github.com/rhondabacher/methylscaper/, and Web: https://methylscaper.com. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
Collapse
Affiliation(s)
- Parker Knight
- Department of Biostatistics, University of Florida, Gainesville, FL
| | | | - Carolina E Pardo
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL
| | - Russell P Darst
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL
| | - Kevin Kapadia
- Department of Statistics, University of Florida, Gainesville, FL
| | - Hadley Browder
- Department of Statistics, University of Florida, Gainesville, FL
| | - Eliza Morton
- Department of Statistics, University of Florida, Gainesville, FL
| | - Alberto Riva
- Bioinformatics Core, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, Florida
| | - Michael P Kladde
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL
| | - Rhonda Bacher
- Department of Biostatistics, University of Florida, Gainesville, FL
| |
Collapse
|
4
|
Ferreira D, Escudeiro A, Adega F, Chaves R. DNA Methylation Patterns of a Satellite Non-coding Sequence - FA-SAT in Cancer Cells: Its Expression Cannot Be Explained Solely by DNA Methylation. Front Genet 2019; 10:101. [PMID: 30809250 PMCID: PMC6379292 DOI: 10.3389/fgene.2019.00101] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 01/29/2019] [Indexed: 02/05/2023] Open
Abstract
Satellite ncRNAs are emerging as key players in cell and cancer pathways. Cancer-linked satellite DNA hypomethylation seems to be responsible for the overexpression of satellite non-coding DNAs in several tumors. FA-SAT is the major satellite DNA of Felis catus and recently, its presence and transcription was described across Bilateria genomes. This satellite DNA is GC-rich and includes a CpG island, what is suggestive of transcription regulation via DNA methylation. In this work, it was studied for the first time the FA-SAT methylation profile in cat primary cells, in four passages of the cat tumor cell line FkMTp and in eight feline mammary tumors and the respective disease-free tissues. Contrary to what was expected, we found that in most of the tumor samples analyzed, FA-SAT DNA was not hypomethylated. Furthermore, in these samples the transcription of FA-SAT does not correlate with the methylation status. The use of a global demethylating agent, 5-Azacytidine, in cat primary cells caused an increase in the FA-SAT non-coding RNA levels. However, global demethylation in the tumor FkMTp cells only resulted in the increased levels of the FA-SAT small RNA fraction. Our data suggests that DNA methylation of FA-SAT is involved in the regulation of this satellite DNA, however, other mechanisms are certainly contributing to the transcriptional status of the sequence, specifically in cancer.
Collapse
Affiliation(s)
- Daniela Ferreira
- Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Lisbon, Portugal
| | - Ana Escudeiro
- Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Lisbon, Portugal
| | - Filomena Adega
- Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Lisbon, Portugal
| | - Raquel Chaves
- Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal.,BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Lisbon, Portugal
| |
Collapse
|
5
|
Chaves R, Ferreira D, Mendes-da-Silva A, Meles S, Adega F. FA-SAT Is an Old Satellite DNA Frozen in Several Bilateria Genomes. Genome Biol Evol 2018; 9:3073-3087. [PMID: 29608678 PMCID: PMC5714208 DOI: 10.1093/gbe/evx212] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2017] [Indexed: 12/17/2022] Open
Abstract
In recent years, a growing body of evidence has recognized the tandem repeat sequences, and specifically satellite DNA, as a functional class of sequences in the genomic “dark matter.” Using an original, complementary, and thus an eclectic experimental design, we show that the cat archetypal satellite DNA sequence, FA-SAT, is “frozen” conservatively in several Bilateria genomes. We found different genomic FA-SAT architectures, and the interspersion pattern was conserved. In Carnivora genomes, the FA-SAT-related sequences are also amplified, with the predominance of a specific FA-SAT variant, at the heterochromatic regions. We inspected the cat genome project to locate FA-SAT array flanking regions and revealed an intensive intermingling with transposable elements. Our results also show that FA-SAT-related sequences are transcribed and that the most abundant FA-SAT variant is not always the most transcribed. We thus conclude that the DNA sequences of FA-SAT and their transcripts are “frozen” in these genomes. Future work is needed to disclose any putative function that these sequences may play in these genomes.
Collapse
Affiliation(s)
- Raquel Chaves
- CAG-Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Portugal
| | - Daniela Ferreira
- CAG-Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Portugal
| | - Ana Mendes-da-Silva
- CAG-Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Portugal
| | - Susana Meles
- CAG-Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Portugal
| | - Filomena Adega
- CAG-Laboratory of Cytogenomics and Animal Genomics, Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Portugal
| |
Collapse
|
6
|
Abstract
Various methodologies are available to interrogate specific components of epigenetic mechanisms such as DNA methylation or nucleosome occupancy at both the locus-specific and the genome-wide level. It has become increasingly clear, however, that comprehension of the functional interactions between epigenetic mechanisms is critical for understanding how cellular transcription programs are regulated or deregulated during normal and disease development. The Nucleosome Occupancy and Methylome sequencing (NOMe-seq) assay allows us to directly measure the relationship between DNA methylation and nucleosome occupancy by taking advantage of the methyltransferase M.CviPI, which methylates unprotected GpC dinucleotides to create a footprint of chromatin accessibility. This assay generates dual nucleosome occupancy and DNA methylation information at a single-DNA molecule resolution using as little as 200,000 cells and in as short as 15 min reaction time. DNA methylation levels and nucleosome occupancy status of genomic regions of interest can be subsequently interrogated by cloning PCR-amplified bisulfite DNA and sequencing individual clones. Alternatively, NOMe-seq can be combined with next-generation sequencing in order to generate an integrated global map of DNA methylation and nucleosome occupancy, which allows for comprehensive examination as to how these epigenetic components correlate with each other.
Collapse
Affiliation(s)
- Fides D Lay
- Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Program in Genetic, Molecular and Cellular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | | | - Peter A Jones
- Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
- Van Andel Institute, 333 Bostwick Ave. NE, Grand Rapids, MI, USA.
| |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Lu Z, Lieber MR, Tsai AG, Pardo CE, Müschen M, Kladde MP, Hsieh CL. Human lymphoid translocation fragile zones are hypomethylated and have accessible chromatin. Mol Cell Biol 2015; 35:1209-22. [PMID: 25624348 PMCID: PMC4355534 DOI: 10.1128/mcb.01085-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Revised: 11/26/2014] [Accepted: 01/16/2015] [Indexed: 12/19/2022] Open
Abstract
Chromosomal translocations are a hallmark of hematopoietic malignancies. CG motifs within translocation fragile zones (typically 20 to 600 bp in size) are prone to chromosomal translocation in lymphomas. Here we demonstrate that the CG motifs in human translocation fragile zones are hypomethylated relative to the adjacent DNA. Using a methyltransferase footprinting assay on isolated nuclei (in vitro), we find that the chromatin at these fragile zones is accessible. We also examined in vivo accessibility using cellular expression of a prokaryotic methylase. Based on this assay, which measures accessibility over a much longer time interval than is possible with in vitro methods, these fragile zones were found to be more accessible than the adjacent DNA. Because DNA within the fragile zones can be methylated by both cellular and exogenous methyltransferases, the fragile zones are predominantly in a duplex DNA conformation. These observations permit more-refined models for why these zones are 100- to 1,000-fold more prone to undergo chromosomal translocation than the adjacent regions.
Collapse
Affiliation(s)
- Zhengfei Lu
- USC Norris Comprehensive Cancer Ctr., Los Angeles, California, USA
| | - Michael R Lieber
- USC Norris Comprehensive Cancer Ctr., Los Angeles, California, USA
| | - Albert G Tsai
- USC Norris Comprehensive Cancer Ctr., Los Angeles, California, USA
| | - Carolina E Pardo
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Markus Müschen
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Michael P Kladde
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Chih-Lin Hsieh
- USC Norris Comprehensive Cancer Ctr., Los Angeles, California, USA
| |
Collapse
|
10
|
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.
Collapse
|
11
|
Gündel M, Younesi E, Malhotra A, Wang J, Li H, Zhang B, de Bono B, Mevissen HT, Hofmann-Apitius M. HuPSON: the human physiology simulation ontology. J Biomed Semantics 2013; 4:35. [PMID: 24267822 PMCID: PMC4177144 DOI: 10.1186/2041-1480-4-35] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 10/07/2013] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Large biomedical simulation initiatives, such as the Virtual Physiological Human (VPH), are substantially dependent on controlled vocabularies to facilitate the exchange of information, of data and of models. Hindering these initiatives is a lack of a comprehensive ontology that covers the essential concepts of the simulation domain. RESULTS We propose a first version of a newly constructed ontology, HuPSON, as a basis for shared semantics and interoperability of simulations, of models, of algorithms and of other resources in this domain. The ontology is based on the Basic Formal Ontology, and adheres to the MIREOT principles; the constructed ontology has been evaluated via structural features, competency questions and use case scenarios.The ontology is freely available at: http://www.scai.fraunhofer.de/en/business-research-areas/bioinformatics/downloads.html (owl files) and http://bishop.scai.fraunhofer.de/scaiview/ (browser). CONCLUSIONS HuPSON provides a framework for a) annotating simulation experiments, b) retrieving relevant information that are required for modelling, c) enabling interoperability of algorithmic approaches used in biomedical simulation, d) comparing simulation results and e) linking knowledge-based approaches to simulation-based approaches. It is meant to foster a more rapid uptake of semantic technologies in the modelling and simulation domain, with particular focus on the VPH domain.
Collapse
Affiliation(s)
- Michaela Gündel
- Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, Sankt Augustin, Germany
- Bonn-Aachen International Center for Information Technology (B-IT), University of Bonn, Bonn, Germany
| | - Erfan Younesi
- Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, Sankt Augustin, Germany
- Bonn-Aachen International Center for Information Technology (B-IT), University of Bonn, Bonn, Germany
| | - Ashutosh Malhotra
- Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, Sankt Augustin, Germany
- Bonn-Aachen International Center for Information Technology (B-IT), University of Bonn, Bonn, Germany
| | - Jiali Wang
- Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, Sankt Augustin, Germany
| | - Hui Li
- Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, Sankt Augustin, Germany
| | - Bijun Zhang
- Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, Sankt Augustin, Germany
| | - Bernard de Bono
- University College London (UCI), Gower Street, WC1E 6BT, London, UK
| | - Heinz-Theodor Mevissen
- Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, Sankt Augustin, Germany
| | - Martin Hofmann-Apitius
- Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, Sankt Augustin, Germany
- Bonn-Aachen International Center for Information Technology (B-IT), University of Bonn, Bonn, Germany
| |
Collapse
|
12
|
Nabilsi NH, Ryder DJ, Peraza-Penton AC, Poudyal R, Loose DS, Kladde MP. Local depletion of DNA methylation identifies a repressive p53 regulatory region in the NEK2 promoter. J Biol Chem 2013; 288:35940-51. [PMID: 24163369 DOI: 10.1074/jbc.m113.523837] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Genome-scale mapping suggests that the function of DNA methylation varies with genomic context beyond transcriptional repression. However, the use of DNA-demethylating agents (e.g. 5-aza-2'-deoxycytidine (5aza-dC)) to study epigenetic regulation often focuses on gene activation and ignores repression elicited by 5aza-dC. Here, we show that repression of NEK2, which encodes the never in mitosis A (NIMA)-related kinase, by 5aza-dC is context-specific as NEK2 transcript levels were reduced in HCT116 colon cancer cells but not in isogenic p53(-/-) cells. Bisulfite sequencing showed that DNA methylation was restricted to the distal region of the NEK2 promoter. Demethylation by 5aza-dC was associated with increased accessibility to micrococcal nuclease, i.e. nucleosome depletion. Conversely, methyltransferase accessibility protocol for individual templates (MAPit) methylation footprinting showed that nucleosome occupancy and DNA methylation at the distal promoter were significantly increased in p53(-/-) cells, suggesting dynamic regulation of chromatin structure at this region by p53 in HCT116 cells. Stabilization of endogenous p53 by doxorubicin or ectopic expression of p53, but not a p53 DNA-binding mutant, decreased NEK2 expression. Chromatin immunoprecipitation demonstrated direct and specific association of p53 with the distal NEK2 promoter, which was enhanced by doxorubicin. Luciferase reporters confirmed that this region is required for p53-mediated repression of NEK2 promoter activity. Lastly, modulation of p53 abundance altered nucleosome occupancy and DNA methylation at its binding region. These results identify NEK2 as a novel p53-repressed gene, illustrate that its repression by 5aza-dC is specific and associated with nucleosome reorganization, and provide evidence that identification of partially methylated regions can reveal novel p53 target genes.
Collapse
Affiliation(s)
- Nancy H Nabilsi
- From the Department of Biochemistry and Molecular Biology, University of Florida Health Cancer Center, University of Florida College of Medicine, Gainesville, Florida 32610
| | | | | | | | | | | |
Collapse
|
13
|
Nabilsi NH, Deleyrolle LP, Darst RP, Riva A, Reynolds BA, Kladde MP. Multiplex mapping of chromatin accessibility and DNA methylation within targeted single molecules identifies epigenetic heterogeneity in neural stem cells and glioblastoma. Genome Res 2013; 24:329-39. [PMID: 24105770 PMCID: PMC3912423 DOI: 10.1101/gr.161737.113] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Human tumors are comprised of heterogeneous cell populations that display diverse molecular and phenotypic features. To examine the extent to which epigenetic differences contribute to intratumoral cellular heterogeneity, we have developed a high-throughput method, termed MAPit-patch. The method uses multiplexed amplification of targeted sequences from submicrogram quantities of genomic DNA followed by next generation bisulfite sequencing. This provides highly scalable and simultaneous mapping of chromatin accessibility and DNA methylation on single molecules at high resolution. Long sequencing reads from targeted regions maintain the structural integrity of epigenetic information and provide substantial depth of coverage, detecting for the first time minority subpopulations of epigenetic configurations formerly obscured by existing genome-wide and population-ensemble methodologies. Analyzing a cohort of 71 promoters of genes with exons commonly mutated in cancer, MAPit-patch uncovered several differentially accessible and methylated promoters that are associated with altered gene expression between neural stem cell (NSC) and glioblastoma (GBM) cell populations. In addition, considering each promoter individually, substantial epigenetic heterogeneity was observed across the sequenced molecules, indicating the presence of epigenetically distinct cellular subpopulations. At the divergent MLH1/EPM2AIP1 promoter, a locus with three well-defined, nucleosome-depleted regions (NDRs), a fraction of promoter copies with inaccessible chromatin was detected and enriched upon selection of temozolomide-tolerant GBM cells. These results illustrate the biological relevance of epigenetically distinct subpopulations that in part underlie the phenotypic heterogeneity of tumor cell populations. Furthermore, these findings show that alterations in chromatin accessibility without accompanying changes in DNA methylation may constitute a novel class of epigenetic biomarker.
Collapse
Affiliation(s)
- Nancy H Nabilsi
- Department of Biochemistry and Molecular Biology, University of Florida Health Cancer Center, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | | | | | | | | | | |
Collapse
|
14
|
Siebzehnrubl FA, Silver DJ, Tugertimur B, Deleyrolle LP, Siebzehnrubl D, Sarkisian MR, Devers KG, Yachnis AT, Kupper MD, Neal D, Nabilsi NH, Kladde MP, Suslov O, Brabletz S, Brabletz T, Reynolds BA, Steindler DA. The ZEB1 pathway links glioblastoma initiation, invasion and chemoresistance. EMBO Mol Med 2013; 5:1196-212. [PMID: 23818228 PMCID: PMC3944461 DOI: 10.1002/emmm.201302827] [Citation(s) in RCA: 296] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/02/2013] [Accepted: 05/06/2013] [Indexed: 12/16/2022] Open
Abstract
Glioblastoma remains one of the most lethal types of cancer, and is the most common brain tumour in adults. In particular, tumour recurrence after surgical resection and radiation invariably occurs regardless of aggressive chemotherapy. Here, we provide evidence that the transcription factor ZEB1 (zinc finger E-box binding homeobox 1) exerts simultaneous influence over invasion, chemoresistance and tumourigenesis in glioblastoma. ZEB1 is preferentially expressed in invasive glioblastoma cells, where the ZEB1-miR-200 feedback loop interconnects these processes through the downstream effectors ROBO1, c-MYB and MGMT. Moreover, ZEB1 expression in glioblastoma patients is predictive of shorter survival and poor Temozolomide response. Our findings indicate that this regulator of epithelial-mesenchymal transition orchestrates key features of cancer stem cells in malignant glioma and identify ROBO1, OLIG2, CD133 and MGMT as novel targets of the ZEB1 pathway. Thus, ZEB1 is an important candidate molecule for glioblastoma recurrence, a marker of invasive tumour cells and a potential therapeutic target, along with its downstream effectors.
Collapse
|
15
|
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.
Collapse
Affiliation(s)
- Smitha R James
- Department of Pharmacology and Therapeutics; Roswell Park Cancer Institute; Buffalo, NY USA
| | | | | | | | | | | | | | | |
Collapse
|
16
|
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.
Collapse
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
| | | | | | | | | |
Collapse
|
17
|
Hossain MB, Vahter M, Concha G, Broberg K. Environmental arsenic exposure and DNA methylation of the tumor suppressor gene p16 and the DNA repair gene MLH1: effect of arsenic metabolism and genotype. Metallomics 2012; 4:1167-75. [PMID: 23073540 DOI: 10.1039/c2mt20120h] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Arsenic is carcinogenic, possibly partly through epigenetic mechanisms. We evaluated the effects of arsenic exposure and metabolism on DNA methylation. Arsenic exposure and methylation efficiency in 202 women in the Argentinean Andes were assessed from concentrations of arsenic metabolites in urine (inorganic arsenic, methylarsonic acid [MMA], and dimethylarsinic acid [DMA]), measured by HPLC-ICPMS. Methylation of CpGs of the tumor suppressor gene p16, the DNA repair gene MLH1, and the repetitive elements LINE1 was measured by PCR pyrosequencing of blood DNA. Genotyping (N = 172) for AS3MT was performed using Sequenom™, and gene expression (N = 90) using Illumina DirectHyb HumanHT-12 v3.0. Median arsenic concentration in urine was 230 μg L(-1) (range 10.1-1251). In linear regression analysis, log(2)-transformed urinary arsenic concentrations were positively associated with methylation of p16 (β = 0.14, P = 0.0028) and MLH1 (β = 0.28, P = 0.0011), but not with LINE1. Arsenic concentrations were of borderline significance negatively correlated with expression of p16 (r(s) = -0.20; P = 0.066)), but not with MLH1. The fraction of inorganic arsenic was positively (β = 0.026; P = 0.010) and DMA was negatively (β = -0.017, P = 0.043) associated with p16 methylation with no effect of MMA. Carriers of the slow-metabolizing AS3MT haplotype were associated with more p16 methylation (P = 0.022). Arsenic exposure was correlated with increased methylation, in blood, of genes encoding enzymes that suppress carcinogenesis, and the arsenic metabolism efficiency modified the degree of epigenetic alterations.
Collapse
Affiliation(s)
- Mohammad Bakhtiar Hossain
- Department of Laboratory Medicine, Division of Occupational and Environmental Medicine, Lund University, Lund, SE-22185, Sweden
| | | | | | | |
Collapse
|
18
|
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.
Collapse
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
| | | | | | | | | | | |
Collapse
|
19
|
Darst RP, Pardo CE, Pondugula S, Gangaraju VK, Nabilsi NH, Bartholomew B, Kladde MP. Simultaneous single-molecule detection of endogenous C-5 DNA methylation and chromatin accessibility using MAPit. Methods Mol Biol 2012; 833:125-41. [PMID: 22183592 DOI: 10.1007/978-1-61779-477-3_9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Bisulfite genomic sequencing provides a single-molecule view of cytosine methylation states. After deamination, each cloned molecule contains a record of methylation within its sequence. The full power of this technique is harnessed by treating nuclei with an exogenous DNMT prior to DNA extraction. This exogenous methylation marks regions of accessibility and footprints nucleosomes, as well as other DNA-binding proteins. Thus, each cloned molecule records not only the endogenous methylation present (at CG sites, in mammals), but also the exogenous (GC, when using the Chlorella virus protein M.CviPI). We term this technique MAPit, methylation accessibility protocol for individual templates.
Collapse
Affiliation(s)
- Russell P Darst
- Department of Biochemistry and Molecular Biology, University of Florida and Shands Cancer Center, University of Florida College of Medicine, Gainesville, FL, USA
| | | | | | | | | | | | | |
Collapse
|
20
|
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.
Collapse
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
| | | | | | | | | |
Collapse
|
21
|
Delmas AL, Riggs BM, Pardo CE, Dyer LM, Darst RP, Izumchenko EG, Monroe M, Hakam A, Kladde MP, Siegel EM, Brown KD. WIF1 is a frequent target for epigenetic silencing in squamous cell carcinoma of the cervix. Carcinogenesis 2011; 32:1625-33. [PMID: 21873353 PMCID: PMC3204350 DOI: 10.1093/carcin/bgr193] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 07/22/2011] [Accepted: 08/08/2011] [Indexed: 02/07/2023] Open
Abstract
Aberrant activation of the Wnt/β-catenin signaling axis is a prominent oncogenic mechanism in numerous cancers including cervical cancer. Wnt inhibitory factor-1 (WIF1) is a secreted protein that binds Wnt and antagonizes Wnt activity. While the WIF1 gene is characterized as a target for epigenetic silencing in some tumor types, WIF1 expression has not been examined in human cervical tissue and cervical cancer. Here, we show that WIF1 is unmethylated and its gene product is expressed in normal cervical epithelium and some cultured cervical tumor lines. In contrast, several cervical cancer lines contained dense CpG methylation within the WIF1 gene, and expression of both WIF1 transcript and protein was restored by culturing cells in the presence of the global DNA demethylating agent 5-aza-2'-deoxycytidine. Using single-molecule MAPit methylation footprinting, we observed differences in chromatin structure within the WIF1 promoter region between cell lines that express and those that do not express WIF1, consistent with transcriptional activity and repression, respectively. The WIF1 promoter was aberrantly methylated in ∼60% (10 of 17) high-grade highly undifferentiated squamous cell cervical tumors examined, whereas paired normal tissue showed significantly lower levels of CpG methylation. WIF1 protein was not detectable by immunohistochemistry in tumors with quantitatively high levels of WIF1 methylation. Of note, WIF1 protein was not detectable in two of the seven unmethylated cervical tumors examined, suggesting other mechanisms may contribute WIF1 repression. Our findings establish the WIF1 gene as a frequent target for epigenetic silencing in squamous cell carcinoma of the cervix.
Collapse
MESH Headings
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Azacitidine/analogs & derivatives
- Azacitidine/pharmacology
- Blotting, Western
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/metabolism
- Carcinoma, Squamous Cell/pathology
- Cell Line
- Cervix Uteri/metabolism
- CpG Islands/genetics
- DNA Methylation
- Decitabine
- Epigenesis, Genetic
- Female
- Gene Expression Regulation, Neoplastic
- Gene Silencing
- Humans
- Immunoenzyme Techniques
- Promoter Regions, Genetic
- RNA, Messenger/genetics
- Repressor Proteins/genetics
- Repressor Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Uterine Cervical Neoplasms/genetics
- Uterine Cervical Neoplasms/metabolism
- Uterine Cervical Neoplasms/pathology
Collapse
Affiliation(s)
| | - Bridget M. Riggs
- Cancer Epidemiology Program, Division of Population Sciences, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612, USA
| | | | | | | | | | - Mänette Monroe
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Ardeshir Hakam
- Department of Anatomic Pathology, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612, USA
| | - Michael P. Kladde
- To whom correspondence should be addressed. Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Box 100245, Gainesville, FL 32610, USA. Tel: +352 273 5458,
| | - Erin M. Siegel
- Cancer Epidemiology Program, Division of Population Sciences, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612, USA
| | - Kevin D. Brown
- To whom correspondence should be addressed. Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Box 100245, Gainesville, FL 32610, USA. Tel: +352 273 5458,
| |
Collapse
|
22
|
Pardo CE, Darst RP, Nabilsi NH, Delmas AL, Kladde MP. Simultaneous single-molecule mapping of protein-DNA interactions and DNA methylation by MAPit. ACTA ACUST UNITED AC 2011; Chapter 21:Unit 21.22. [PMID: 21732317 DOI: 10.1002/0471142727.mb2122s95] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Sites of protein binding to DNA are inferred from footprints or spans of protection against a probing reagent. In most protocols, sites of accessibility to a probe are detected by mapping breaks in DNA strands. As discussed in this unit, such methods obscure molecular heterogeneity by averaging cuts at a given site over all DNA strands in a sample population. The DNA methyltransferase accessibility protocol for individual templates (MAPit), an alternative method described in this unit, localizes protein-DNA interactions by probing with cytosine-modifying DNA methyltransferases followed by bisulfite sequencing. Sequencing individual DNA products after amplification of bisulfite-converted sequences permits assignment of the methylation status of every enzyme target site along a single DNA strand. Use of the GC-methylating enzyme M.CviPI allows simultaneous mapping of chromatin accessibility and endogenous CpG methylation. MAPit is therefore the only footprinting method that can detect subpopulations of molecules with distinct patterns of protein binding or chromatin architecture and correlate them directly with the occurrence of endogenous methylation. Additional advantages of MAPit methylation footprinting as well as considerations for experimental design and potential sources of error are discussed.
Collapse
Affiliation(s)
- Carolina E Pardo
- Department of Biochemistry and Molecular Biology and UF Shands Cancer Center Program in Cancer Genetics, Epigenetics and Tumor Virology, University of Florida College of Medicine, Gainesville, Florida, USA
| | | | | | | | | |
Collapse
|
23
|
Abstract
The genomic organization of chromatin is increasingly recognized as a key regulator of cell behavior, but deciphering its regulation mechanisms requires detailed knowledge of chromatin's primary structure-the assembly of nucleosomes throughout the genome. This Primer explains the principles for mapping and analyzing the primary organization of chromatin on a genomic scale. After introducing chromatin organization and its impact on gene regulation and human health, we then describe methods that detect nucleosome positioning and occupancy levels using chromatin immunoprecipitation in combination with deep sequencing (ChIP-Seq), a strategy that is now straightforward and cost efficient. We then explore current strategies for converting the sequence information into knowledge about chromatin, an exciting challenge for biologists and bioinformaticians.
Collapse
Affiliation(s)
- Zhenhai Zhang
- Center for Comparative Genomics and Bioinformatics, Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | - B. Franklin Pugh
- Center for Comparative Genomics and Bioinformatics, Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| |
Collapse
|