1
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Andersson E, Rothenberg EV, Peterson C, Olariu V. T-cell commitment inheritance-an agent-based multi-scale model. NPJ Syst Biol Appl 2024; 10:40. [PMID: 38632273 PMCID: PMC11024127 DOI: 10.1038/s41540-024-00368-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 04/08/2024] [Indexed: 04/19/2024] Open
Abstract
T-cell development provides an excellent model system for studying lineage commitment from a multipotent progenitor. The intrathymic development process has been thoroughly studied. The molecular circuitry controlling it has been dissected and the necessary steps like programmed shut off of progenitor genes and T-cell genes upregulation have been revealed. However, the exact timing between decision-making and commitment stage remains unexplored. To this end, we implemented an agent-based multi-scale model to investigate inheritance in early T-cell development. Treating each cell as an agent provides a powerful tool as it tracks each individual cell of a simulated T-cell colony, enabling the construction of lineage trees. Based on the lineage trees, we introduce the concept of the last common ancestors (LCA) of committed cells and analyse their relations, both at single-cell level and population level. In addition to simulating wild-type development, we also conduct knockdown analysis. Our simulations predicted that the commitment is a three-step process that occurs on average over several cell generations once a cell is first prepared by a transcriptional switch. This is followed by the loss of the Bcl11b-opposing function approximately two to three generations later. This is when our LCA analysis indicates that the decision to commit is taken even though in general another one to two generations elapse before the cell actually becomes committed by transitioning to the DN2b state. Our results showed that there is decision inheritance in the commitment mechanism.
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Affiliation(s)
- Emil Andersson
- Computational Science for Health and Environment, Centre for Environmental and Climate Science, Lund University, Lund, Sweden
| | - Ellen V Rothenberg
- Division of Biology and Biological Engineering, 156-29, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Carsten Peterson
- Computational Science for Health and Environment, Centre for Environmental and Climate Science, Lund University, Lund, Sweden
| | - Victor Olariu
- Computational Science for Health and Environment, Centre for Environmental and Climate Science, Lund University, Lund, Sweden.
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2
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Wieting J, Jahn K, Bleich S, Frieling H, Deest M. A targeted long-read sequencing approach questions the association of OXTR methylation with high-functioning autism. Clin Epigenetics 2023; 15:195. [PMID: 38124130 PMCID: PMC10734107 DOI: 10.1186/s13148-023-01616-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023] Open
Abstract
BACKGROUND DNA sequence variation and altered epigenetic regulation of the oxytocin receptor gene (OXTR) have been implicated in autism and autistic-like behaviors. While previous studies have examined subsegments of OXTR, nanopore Cas9-targeted sequencing (nCATS) allows deep characterization of entire genes with simultaneous assessment of epigenetic 5-methylcytosine (5mC) modification and without the need for prior DNA amplification or bisulfite conversion. This pilot study uses an nCATS approach to sequence the entire OXTR gene and its regulatory construct and screen for 5mC modification to compare results between individuals with high-functioning autism (HFA) and neurotypical controls (NC). METHODS Using DNA extracted from peripheral blood, OXTR (Hg38, chr3: 8750381-8770434, 20,054 base pairs) was analyzed by nCATS. 5mC modification probabilities were calculated and visualized across the gene and differential methylation analysis was performed. RESULTS Twenty adults with HFA (10 males, 10 females) and 20 age- and sex-matched NC (± 5 years) were included. There were no apparent group differences in the entire OXTR gene sequence, except for the intron variant rs918316, which was clustered in the HFA group. However, differential methylation analysis did not reveal a single significant group-dependent differentially methylated site among the 412 CpG sites captured. LIMITATIONS Limitations of this study include the small number of samples due to the pilot nature of the study, which particularly limits the relevance of the sequence variants found. It should also be noted that the use of peripheral blood material limits the ability to draw conclusions about central processes. CONCLUSIONS Previous findings of autism-associated OXTR epigenetic alterations were not reproducible with our method. In our opinion, this may lead to a reconsideration of the relevance of altered methylation at individual OXTR CpG positions in autism research. However, given the pilot nature of the study, these results need to be replicated in independent cohorts and with larger sample sizes.
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Affiliation(s)
- Jelte Wieting
- Hannover Medical School, Department of Psychiatry, Social Psychiatry and Psychotherapy, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
- Laboratory for Molecular Neuroscience, Feodor-Lynen-Str. 35, 30625, Hannover, Germany.
| | - Kirsten Jahn
- Laboratory for Molecular Neuroscience, Feodor-Lynen-Str. 35, 30625, Hannover, Germany
| | - Stefan Bleich
- Hannover Medical School, Department of Psychiatry, Social Psychiatry and Psychotherapy, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
- Laboratory for Molecular Neuroscience, Feodor-Lynen-Str. 35, 30625, Hannover, Germany
| | - Helge Frieling
- Hannover Medical School, Department of Psychiatry, Social Psychiatry and Psychotherapy, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
- Laboratory for Molecular Neuroscience, Feodor-Lynen-Str. 35, 30625, Hannover, Germany
| | - Maximilian Deest
- Hannover Medical School, Department of Psychiatry, Social Psychiatry and Psychotherapy, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
- Laboratory for Molecular Neuroscience, Feodor-Lynen-Str. 35, 30625, Hannover, Germany
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3
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Briffa A, Hollwey E, Shahzad Z, Moore JD, Lyons DB, Howard M, Zilberman D. Millennia-long epigenetic fluctuations generate intragenic DNA methylation variance in Arabidopsis populations. Cell Syst 2023; 14:953-967.e17. [PMID: 37944515 DOI: 10.1016/j.cels.2023.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 07/18/2023] [Accepted: 10/13/2023] [Indexed: 11/12/2023]
Abstract
Methylation of CG dinucleotides (mCGs), which regulates eukaryotic genome functions, is epigenetically propagated by Dnmt1/MET1 methyltransferases. How mCG is established and transmitted across generations despite imperfect enzyme fidelity is unclear. Whether mCG variation in natural populations is governed by genetic or epigenetic inheritance also remains mysterious. Here, we show that MET1 de novo activity, which is enhanced by existing proximate methylation, seeds and stabilizes mCG in Arabidopsis thaliana genes. MET1 activity is restricted by active demethylation and suppressed by histone variant H2A.Z, producing localized mCG patterns. Based on these observations, we develop a stochastic mathematical model that precisely recapitulates mCG inheritance dynamics and predicts intragenic mCG patterns and their population-scale variation given only CG site spacing. Our results demonstrate that intragenic mCG establishment, inheritance, and variance constitute a unified epigenetic process, revealing that intragenic mCG undergoes large, millennia-long epigenetic fluctuations and can therefore mediate evolution on this timescale.
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Affiliation(s)
- Amy Briffa
- Department of Computational and Systems Biology, John Innes Centre, Norwich NR4 7UH, UK
| | - Elizabeth Hollwey
- Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK; Institute of Science and Technology, 3400 Klosterneuburg, Austria
| | - Zaigham Shahzad
- Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK; Department of Life Sciences, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
| | - Jonathan D Moore
- Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK
| | - David B Lyons
- Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK
| | - Martin Howard
- Department of Computational and Systems Biology, John Innes Centre, Norwich NR4 7UH, UK.
| | - Daniel Zilberman
- Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK; Institute of Science and Technology, 3400 Klosterneuburg, Austria.
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4
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Andersson E, Rothenberg EV, Peterson C, Olariu V. T-cell commitment inheritance - an agent-based multi-scale model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.18.562905. [PMID: 37905091 PMCID: PMC10614897 DOI: 10.1101/2023.10.18.562905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
T-cell development provides an excellent model system for studying lineage commitment from a multipotent progenitor. The intrathymic development process has been thoroughly studied. The molecular circuitry controlling it has been dissected and the necessary steps like programmed shut off of progenitor genes and T-cell genes upregulation have been revealed. However, the exact timing between decision-making and commitment stage remains unexplored. To this end, we implemented an agent-based multi-scale model to investigate inheritance in early T-cell development. Treating each cell as an agent provides a powerful tool as it tracks each individual cell of a simulated T-cell colony, enabling the construction of lineage trees. Based on the lineage trees, we introduce the concept of the last common ancestors (LCA) of committed cells and analyse their relations, both at single-cell level and population level. In addition to simulating wild-type development, we also conduct knockdown analysis. Our simulations showed that the commitment is a three-step process over several cell generations where a cell is first prepared by a transcriptional switch. This is followed by the loss of the Bcl11b-opposing function two to three generations later which is when the decision to commit is taken. Finally, after another one to two generations, the cell becomes committed by transitioning to the DN2b state. Our results showed that there is inheritance in the commitment mechanism.
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Affiliation(s)
- Emil Andersson
- Computational Biology and Biological Physics, Centre for Environmental and Climate Science, Lund University, Lund, Sweden
| | - Ellen V. Rothenberg
- Division of Biology and Biological Engineering, 156-29, California Institute of Technology, Pasadena, CA 91125, USA
| | - Carsten Peterson
- Computational Biology and Biological Physics, Centre for Environmental and Climate Science, Lund University, Lund, Sweden
| | - Victor Olariu
- Computational Biology and Biological Physics, Centre for Environmental and Climate Science, Lund University, Lund, Sweden
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5
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Kerr L, Kafetzopoulos I, Grima R, Sproul D. Genome-wide single-molecule analysis of long-read DNA methylation reveals heterogeneous patterns at heterochromatin that reflect nucleosome organisation. PLoS Genet 2023; 19:e1010958. [PMID: 37782664 PMCID: PMC10569558 DOI: 10.1371/journal.pgen.1010958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 10/12/2023] [Accepted: 09/04/2023] [Indexed: 10/04/2023] Open
Abstract
High-throughput sequencing technology is central to our current understanding of the human methylome. The vast majority of studies use chemical conversion to analyse bulk-level patterns of DNA methylation across the genome from a population of cells. While this technology has been used to probe single-molecule methylation patterns, such analyses are limited to short reads of a few hundred basepairs. DNA methylation can also be directly detected using Nanopore sequencing which can generate reads measuring megabases in length. However, thus far these analyses have largely focused on bulk-level assessment of DNA methylation. Here, we analyse DNA methylation in single Nanopore reads from human lymphoblastoid cells, to show that bulk-level metrics underestimate large-scale heterogeneity in the methylome. We use the correlation in methylation state between neighbouring sites to quantify single-molecule heterogeneity and find that heterogeneity varies significantly across the human genome, with some regions having heterogeneous methylation patterns at the single-molecule level and others possessing more homogeneous methylation patterns. By comparing the genomic distribution of the correlation to epigenomic annotations, we find that the greatest heterogeneity in single-molecule patterns is observed within heterochromatic partially methylated domains (PMDs). In contrast, reads originating from euchromatic regions and gene bodies have more ordered DNA methylation patterns. By analysing the patterns of single molecules in more detail, we show the existence of a nucleosome-scale periodicity in DNA methylation that accounts for some of the heterogeneity we uncover in long single-molecule DNA methylation patterns. We find that this periodic structure is partially masked in bulk data and correlates with DNA accessibility as measured by nanoNOMe-seq, suggesting that it could be generated by nucleosomes. Our findings demonstrate the power of single-molecule analysis of long-read data to understand the structure of the human methylome.
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Affiliation(s)
- Lyndsay Kerr
- MRC Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom
| | - Ioannis Kafetzopoulos
- MRC Human Genetics Unit and CRUK Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom
- Current address: Altos Labs Cambridge Institute, Cambridge, United Kingdom
| | - Ramon Grima
- School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Duncan Sproul
- MRC Human Genetics Unit and CRUK Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom
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6
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Ma Y, Budde MW, Zhu J, Elowitz MB. Tuning Methylation-Dependent Silencing Dynamics by Synthetic Modulation of CpG Density. ACS Synth Biol 2023; 12:2536-2545. [PMID: 37572041 PMCID: PMC10510725 DOI: 10.1021/acssynbio.3c00078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Indexed: 08/14/2023]
Abstract
Methylation of cytosines in CG dinucleotides (CpGs) within promoters has been shown to lead to gene silencing in mammals in natural contexts. Recently, engineered recruitment of methyltransferases (DNMTs) at specific loci was shown to be sufficient to silence synthetic and endogenous gene expression through this mechanism. A critical parameter for DNA methylation-based silencing is the distribution of CpGs within the target promoter. However, how the number or density of CpGs in the target promoter affects the dynamics of silencing by DNMT recruitment has remained unclear. Here, we constructed a library of promoters with systematically varying CpG content, and analyzed the rate of silencing in response to recruitment of DNMT. We observed a tight correlation between silencing rate and CpG content. Further, methylation-specific analysis revealed a constant accumulation rate of methylation at the promoter after DNMT recruitment. We identified a single CpG site between TATA box and transcription start site (TSS) that accounted for a substantial part of the difference in silencing rates between promoters with differing CpG content, indicating that certain residues play disproportionate roles in controlling silencing. Together, these results provide a library of promoters for synthetic epigenetic and gene regulation applications, as well as insights into the regulatory link between CpG content and silencing rate.
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Affiliation(s)
- Yitong Ma
- Division
of Biology and Biological Engineering, California
Institute of Technology, Pasadena, California 91125, United States
| | - Mark W. Budde
- Division
of Biology and Biological Engineering, California
Institute of Technology, Pasadena, California 91125, United States
- Primordium
Labs, Arcadia, California 91006, United States
| | - Junqin Zhu
- Department
of Biology, Stanford University, Stanford, California 94305, United States
| | - Michael B. Elowitz
- Division
of Biology and Biological Engineering, California
Institute of Technology, Pasadena, California 91125, United States
- Howard
Hughes Medical Institute, California Institute
of Technology, Pasadena, California 91125, United States
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7
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Hollwey E, Briffa A, Howard M, Zilberman D. Concepts, mechanisms and implications of long-term epigenetic inheritance. Curr Opin Genet Dev 2023; 81:102087. [PMID: 37441873 DOI: 10.1016/j.gde.2023.102087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023]
Abstract
Many modes and mechanisms of epigenetic inheritance have been elucidated in eukaryotes. Most of them are relatively short-term, generally not exceeding one or a few organismal generations. However, emerging evidence indicates that one mechanism, cytosine DNA methylation, can mediate epigenetic inheritance over much longer timescales, which are mostly or completely inaccessible in the laboratory. Here we discuss the evidence for, and mechanisms and implications of, such long-term epigenetic inheritance. We argue that compelling evidence supports the long-term epigenetic inheritance of gene body methylation, at least in the model angiosperm Arabidopsis thaliana, and that variation in such methylation can therefore serve as an epigenetic basis for phenotypic variation in natural populations.
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Affiliation(s)
| | - Amy Briffa
- Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Martin Howard
- Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Daniel Zilberman
- Institute of Science and Technology, 3400 Klosterneuburg, Austria.
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8
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Ma Y, Budde MW, Zhu J, Elowitz MB. Tuning methylation-dependent silencing dynamics by synthetic modulation of CpG density. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.30.542205. [PMID: 37398290 PMCID: PMC10312471 DOI: 10.1101/2023.05.30.542205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Methylation of cytosines in CG dinucleotides (CpGs) within promoters has been shown to lead to gene silencing in mammals in natural contexts. Recently, engineered recruitment of methyltransferases (DNMTs) at specific loci was shown to be sufficient to silence synthetic and endogenous gene expression through this mechanism. A critical parameter for DNA methylation-based silencing is the distribution of CpGs within the target promoter. However, how the number or density of CpGs in the target promoter affects the dynamics of silencing by DNMT recruitment has remained unclear. Here we constructed a library of promoters with systematically varying CpG content, and analyzed the rate of silencing in response to recruitment of DNMT. We observed a tight correlation between silencing rate and CpG content. Further, methylation-specific analysis revealed a constant accumulation rate of methylation at the promoter after DNMT recruitment. We identified a single CpG site between TATA box and transcription start site (TSS) that accounted for a substantial part of the difference in silencing rates between promoters with differing CpG content, indicating that certain residues play disproportionate roles in controlling silencing. Together, these results provide a library of promoters for synthetic epigenetic and gene regulation applications, as well as insights into the regulatory link between CpG content and silencing rate.
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Affiliation(s)
- Yitong Ma
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA91125, USA
| | - Mark W. Budde
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA91125, USA
- Primordium Labs, Arcadia, CA 91006, USA
| | - Junqin Zhu
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Michael B. Elowitz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
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9
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Lyons DB, Briffa A, He S, Choi J, Hollwey E, Colicchio J, Anderson I, Feng X, Howard M, Zilberman D. Extensive de novo activity stabilizes epigenetic inheritance of CG methylation in Arabidopsis transposons. Cell Rep 2023; 42:112132. [PMID: 36827183 DOI: 10.1016/j.celrep.2023.112132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 11/10/2022] [Accepted: 02/01/2023] [Indexed: 02/24/2023] Open
Abstract
Cytosine methylation within CG dinucleotides (mCG) can be epigenetically inherited over many generations. Such inheritance is thought to be mediated by a semiconservative mechanism that produces binary present/absent methylation patterns. However, we show here that, in Arabidopsis thaliana h1ddm1 mutants, intermediate heterochromatic mCG is stably inherited across many generations and is quantitatively associated with transposon expression. We develop a mathematical model that estimates the rates of semiconservative maintenance failure and de novo methylation at each transposon, demonstrating that mCG can be stably inherited at any level via a dynamic balance of these activities. We find that DRM2-the core methyltransferase of the RNA-directed DNA methylation pathway-catalyzes most of the heterochromatic de novo mCG, with de novo rates orders of magnitude higher than previously thought, whereas chromomethylases make smaller contributions. Our results demonstrate that stable epigenetic inheritance of mCG in plant heterochromatin is enabled by extensive de novo methylation.
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Affiliation(s)
| | | | | | | | - Elizabeth Hollwey
- John Innes Centre, Norwich NR4 7UH, UK; Institute of Science and Technology, 3400 Klosterneuburg, Austria
| | - Jack Colicchio
- Department of Plant & Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Ian Anderson
- Department of Plant & Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Xiaoqi Feng
- John Innes Centre, Norwich NR4 7UH, UK; Institute of Science and Technology, 3400 Klosterneuburg, Austria
| | | | - Daniel Zilberman
- John Innes Centre, Norwich NR4 7UH, UK; Institute of Science and Technology, 3400 Klosterneuburg, Austria.
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10
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De Riso G, Sarnataro A, Scala G, Cuomo M, Della Monica R, Amente S, Chiariotti L, Miele G, Cocozza S. MC profiling: a novel approach to analyze DNA methylation heterogeneity in genome-wide bisulfite sequencing data. NAR Genom Bioinform 2022; 4:lqac096. [PMID: 36601577 PMCID: PMC9803872 DOI: 10.1093/nargab/lqac096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/24/2022] [Accepted: 12/08/2022] [Indexed: 01/01/2023] Open
Abstract
DNA methylation is an epigenetic mark implicated in crucial biological processes. Most of the knowledge about DNA methylation is based on bulk experiments, in which DNA methylation of genomic regions is reported as average methylation. However, average methylation does not inform on how methylated cytosines are distributed in each single DNA molecule. Here, we propose Methylation Class (MC) profiling as a genome-wide approach to the study of DNA methylation heterogeneity from bulk bisulfite sequencing experiments. The proposed approach is built on the concept of MCs, groups of DNA molecules sharing the same number of methylated cytosines. The relative abundances of MCs from sequencing reads incorporates the information on the average methylation, and directly informs on the methylation level of each molecule. By applying our approach to publicly available bisulfite-sequencing datasets, we individuated cell-to-cell differences as the prevalent contributor to methylation heterogeneity. Moreover, we individuated signatures of loci undergoing imprinting and X-inactivation, and highlighted differences between the two processes. When applying MC profiling to compare different conditions, we identified methylation changes occurring in regions with almost constant average methylation. Altogether, our results indicate that MC profiling can provide useful insights on the epigenetic status and its evolution at multiple genomic regions.
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Affiliation(s)
- Giulia De Riso
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via Sergio Pansini 5, 80131 Naples, Italy
| | - Antonella Sarnataro
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via Sergio Pansini 5, 80131 Naples, Italy
| | - Giovanni Scala
- Department of Biology, University of Naples Federico II, Via Vicinale Cupa Cintia 21, 80126 Naples, Italy
| | - Mariella Cuomo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via Sergio Pansini 5, 80131 Naples, Italy
- CEINGE - Biotecnologie Avanzate, Via Gaetano Salvatore, 486, 80145 Naples, Italy
| | - Rosa Della Monica
- CEINGE - Biotecnologie Avanzate, Via Gaetano Salvatore, 486, 80145 Naples, Italy
| | - Stefano Amente
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via Sergio Pansini 5, 80131 Naples, Italy
| | - Lorenzo Chiariotti
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via Sergio Pansini 5, 80131 Naples, Italy
- CEINGE - Biotecnologie Avanzate, Via Gaetano Salvatore, 486, 80145 Naples, Italy
| | - Gennaro Miele
- Department of Physics “E. Pancini”, University of Naples “Federico II”, Via Cinthia, 80126 Naples, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Napoli, 80126 Naples, Italy
| | - Sergio Cocozza
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via Sergio Pansini 5, 80131 Naples, Italy
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11
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Higham J, Kerr L, Zhang Q, Walker RM, Harris SE, Howard DM, Hawkins EL, Sandu AL, Steele JD, Waiter GD, Murray AD, Evans KL, McIntosh AM, Visscher PM, Deary IJ, Cox SR, Sproul D. Local CpG density affects the trajectory and variance of age-associated DNA methylation changes. Genome Biol 2022; 23:216. [PMID: 36253871 PMCID: PMC9575273 DOI: 10.1186/s13059-022-02787-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 10/05/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND DNA methylation is an epigenetic mark associated with the repression of gene promoters. Its pattern in the genome is disrupted with age and these changes can be used to statistically predict age with epigenetic clocks. Altered rates of aging inferred from these clocks are observed in human disease. However, the molecular mechanisms underpinning age-associated DNA methylation changes remain unknown. Local DNA sequence can program steady-state DNA methylation levels, but how it influences age-associated methylation changes is unknown. RESULTS We analyze longitudinal human DNA methylation trajectories at 345,895 CpGs from 600 individuals aged between 67 and 80 to understand the factors responsible for age-associated epigenetic changes at individual CpGs. We show that changes in methylation with age occur at 182,760 loci largely independently of variation in cell type proportions. These changes are especially apparent at 8322 low CpG density loci. Using SNP data from the same individuals, we demonstrate that methylation trajectories are affected by local sequence polymorphisms at 1487 low CpG density loci. More generally, we find that low CpG density regions are particularly prone to change and do so variably between individuals in people aged over 65. This differs from the behavior of these regions in younger individuals where they predominantly lose methylation. CONCLUSIONS Our results, which we reproduce in two independent groups of individuals, demonstrate that local DNA sequence influences age-associated DNA methylation changes in humans in vivo. We suggest that this occurs because interactions between CpGs reinforce maintenance of methylation patterns in CpG dense regions.
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Affiliation(s)
- Jonathan Higham
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
| | - Lyndsay Kerr
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
| | - Qian Zhang
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, Australia
- Present address: Wellcome Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Rosie M Walker
- Centre for Genomic and Experimental Medicine, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
- Present address: School of Psychology, University of Exeter, Edinburgh, UK
| | - Sarah E Harris
- Department of Psychology, Lothian Birth Cohorts Group, University of Edinburgh, Edinburgh, UK
| | - David M Howard
- Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- Division of Psychiatry, University of Edinburgh, Royal Edinburgh Hospital, Edinburgh, UK
| | - Emma L Hawkins
- Division of Psychiatry, University of Edinburgh, Royal Edinburgh Hospital, Edinburgh, UK
| | - Anca-Larisa Sandu
- Aberdeen Biomedical Imaging Centre, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - J Douglas Steele
- Division of Imaging Science and Technology, Medical School, University of Dundee, Dundee, UK
| | - Gordon D Waiter
- Aberdeen Biomedical Imaging Centre, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Alison D Murray
- Aberdeen Biomedical Imaging Centre, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Kathryn L Evans
- Centre for Genomic and Experimental Medicine, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
| | - Andrew M McIntosh
- Division of Psychiatry, University of Edinburgh, Royal Edinburgh Hospital, Edinburgh, UK
| | - Peter M Visscher
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, Australia
| | - Ian J Deary
- Department of Psychology, Lothian Birth Cohorts Group, University of Edinburgh, Edinburgh, UK
| | - Simon R Cox
- Department of Psychology, Lothian Birth Cohorts Group, University of Edinburgh, Edinburgh, UK
| | - Duncan Sproul
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK.
- CRUK Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK.
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12
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Ren H, Taylor RB, Downing TL, Read EL. Locally correlated kinetics of post-replication DNA methylation reveals processivity and region specificity in DNA methylation maintenance. J R Soc Interface 2022; 19:20220415. [PMID: 36285438 PMCID: PMC9597173 DOI: 10.1098/rsif.2022.0415] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
DNA methylation occurs predominantly on cytosine-phosphate-guanine (CpG) dinucleotides in the mammalian genome, and the methylation landscape is maintained over mitotic cell division. It has been posited that coupling of maintenance methylation activity among neighbouring CpGs is critical to stability over cellular generations; however, the mechanism is unclear. We used mathematical models and stochastic simulation to analyse data from experiments that probe genome-wide methylation of nascent DNA post-replication in cells. We find that DNA methylation maintenance rates on individual CpGs are locally correlated, and the degree of this correlation varies by genomic regional context. By using theory of protein diffusion along DNA, we show that exponential decay of methylation rate correlation with genomic distance is consistent with enzyme processivity. Our results provide quantitative evidence of genome-wide methyltransferase processivity in vivo. We further developed a method to disentangle different mechanistic sources of kinetic correlations. From the experimental data, we estimate that an individual methyltransferase methylates neighbour CpGs processively if they are 36 basepairs apart, on average. But other mechanisms of coupling dominate for longer inter-CpG distances. Our study demonstrates that quantitative insights into enzymatic mechanisms can be obtained from replication-associated, cell-based genome-wide measurements, by combining data-driven statistical analyses with hypothesis-driven mathematical modelling.
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Affiliation(s)
- Honglei Ren
- NSF-Simons Center for Multiscale Cell Fate, University of California, Irvine, CA 92697, USA,Center for Complex Biological Systems, University of California, Irvine, CA 92697, USA
| | - Robert B. Taylor
- Center for Complex Biological Systems, University of California, Irvine, CA 92697, USA,Department of Physics, University of California, Irvine, CA 92697, USA
| | - Timothy L. Downing
- NSF-Simons Center for Multiscale Cell Fate, University of California, Irvine, CA 92697, USA,Center for Complex Biological Systems, University of California, Irvine, CA 92697, USA,Department of Biomedical Engineering, University of California, Irvine, CA 92697, USA,Department of Microbiology and Molecular Genetics, University of California, Irvine, CA 92697, USA
| | - Elizabeth L. Read
- NSF-Simons Center for Multiscale Cell Fate, University of California, Irvine, CA 92697, USA,Department of Chemical and Biomolecular Engineering, University of California, Irvine, CA 92697, USA,Center for Complex Biological Systems, University of California, Irvine, CA 92697, USA
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13
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Seale K, Horvath S, Teschendorff A, Eynon N, Voisin S. Making sense of the ageing methylome. Nat Rev Genet 2022; 23:585-605. [PMID: 35501397 DOI: 10.1038/s41576-022-00477-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2022] [Indexed: 12/22/2022]
Abstract
Over time, the human DNA methylation landscape accrues substantial damage, which has been associated with a broad range of age-related diseases, including cardiovascular disease and cancer. Various age-related DNA methylation changes have been described, including at the level of individual CpGs, such as differential and variable methylation, and at the level of the whole methylome, including entropy and correlation networks. Here, we review these changes in the ageing methylome as well as the statistical tools that can be used to quantify them. We detail the evidence linking DNA methylation to ageing phenotypes and the longevity strategies aimed at altering both DNA methylation patterns and machinery to extend healthspan and lifespan. Lastly, we discuss theories on the mechanistic causes of epigenetic ageing.
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Affiliation(s)
- Kirsten Seale
- Institute for Health and Sport (iHeS), Victoria University, Footscray, Melbourne, Victoria, Australia
| | - Steve Horvath
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.,Altos Labs, San Diego, CA, USA
| | - Andrew Teschendorff
- CAS Key Laboratory of Computational Biology, Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China.,UCL Cancer Institute, University College London, London, UK
| | - Nir Eynon
- Institute for Health and Sport (iHeS), Victoria University, Footscray, Melbourne, Victoria, Australia.
| | - Sarah Voisin
- Institute for Health and Sport (iHeS), Victoria University, Footscray, Melbourne, Victoria, Australia.
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14
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Kerr L, Sproul D, Grima R. Cluster mean-field theory accurately predicts statistical properties of large-scale DNA methylation patterns. J R Soc Interface 2022; 19:20210707. [PMID: 35078341 PMCID: PMC8790364 DOI: 10.1098/rsif.2021.0707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 12/13/2021] [Indexed: 11/12/2022] Open
Abstract
The accurate establishment and maintenance of DNA methylation patterns is vital for mammalian development and disruption to these processes causes human disease. Our understanding of DNA methylation mechanisms has been facilitated by mathematical modelling, particularly stochastic simulations. Megabase-scale variation in DNA methylation patterns is observed in development, cancer and ageing and the mechanisms generating these patterns are little understood. However, the computational cost of stochastic simulations prevents them from modelling such large genomic regions. Here, we test the utility of three different mean-field models to predict summary statistics associated with large-scale DNA methylation patterns. By comparison to stochastic simulations, we show that a cluster mean-field model accurately predicts the statistical properties of steady-state DNA methylation patterns, including the mean and variance of methylation levels calculated across a system of CpG sites, as well as the covariance and correlation of methylation levels between neighbouring sites. We also demonstrate that a cluster mean-field model can be used within an approximate Bayesian computation framework to accurately infer model parameters from data. As mean-field models can be solved numerically in a few seconds, our work demonstrates their utility for understanding the processes underpinning large-scale DNA methylation patterns.
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Affiliation(s)
- Lyndsay Kerr
- MRC Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
| | - Duncan Sproul
- MRC Human Genetics Unit and CRUK Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
| | - Ramon Grima
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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15
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Zagkos L, Roberts J, Auley MM. A mathematical model which examines age-related stochastic fluctuations in DNA maintenance methylation. Exp Gerontol 2021; 156:111623. [PMID: 34774717 DOI: 10.1016/j.exger.2021.111623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 10/30/2021] [Accepted: 11/04/2021] [Indexed: 10/19/2022]
Abstract
Due to its complexity and its ubiquitous nature the ageing process remains an enduring biological puzzle. Many molecular mechanisms and biochemical process have become synonymous with ageing. However, recent findings have pinpointed epigenetics as having a key role in ageing and healthspan. In particular age related changes to DNA methylation offer the possibility of monitoring the trajectory of biological ageing and could even be used to predict the onset of diseases such as cancer, Alzheimer's disease and cardiovascular disease. At the molecular level emerging evidence strongly suggests the regulatory processes which govern DNA methylation are subject to intracellular stochasticity. It is challenging to fully understand the impact of stochasticity on DNA methylation levels at the molecular level experimentally. An ideal solution is to use mathematical models to capture the essence of the stochasticity and its outcomes. In this paper we present a novel stochastic model which accounts for specific methylation levels within a gene promoter. Uncertainty of the eventual site-specific methylation levels for different values of methylation age, depending on the initial methylation levels were analysed. Our model predicts the observed bistable levels in CpG islands. In addition, simulations with various levels of noise indicate that uncertainty predominantly spreads through the hypermethylated region of stability, especially for large values of input noise. A key outcome of the model is that CpG islands with high to intermediate methylation levels tend to be more susceptible to dramatic DNA methylation changes due to increasing methylation age.
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Affiliation(s)
- Loukas Zagkos
- Department of Mathematics, School of Science and Engineering, University of Chester, Thornton Science Park, Chester CH2 4NU, UK; Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, St Mary's Campus, London W2 1PG, UK.
| | - Jason Roberts
- Department of Mathematics, School of Science and Engineering, University of Chester, Thornton Science Park, Chester CH2 4NU, UK
| | - Mark Mc Auley
- Department of Chemical Engineering, School of Science and Engineering, University of Chester, Thornton Science Park, Chester CH2 4NU, UK
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16
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Abstract
Epigenetics has enriched human disease studies by adding new interpretations to disease features that cannot be explained by genetic and environmental factors. However, identifying causal mechanisms of epigenetic origin has been challenging. New opportunities have risen from recent findings in intra-individual and cyclical epigenetic variation, which includes circadian epigenetic oscillations. Cytosine modifications display deterministic temporal rhythms, which may drive ageing and complex disease. Temporality in the epigenome, or the 'chrono' dimension, may help the integration of epigenetic, environmental and genetic disease studies, and reconcile several disparities stemming from the arbitrarily delimited research fields. The ultimate goal of chrono-epigenetics is to predict disease risk, age of onset and disease dynamics from within individual-specific temporal dynamics of epigenomes.
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17
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Liang L, Ma K, Wang Z, Janissen R, Yu Z. Dynamics and inhibition of MLL1 CXXC domain on DNA revealed by single-molecule quantification. Biophys J 2021; 120:3283-3291. [PMID: 34280370 DOI: 10.1016/j.bpj.2021.03.045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/09/2021] [Accepted: 03/11/2021] [Indexed: 02/05/2023] Open
Abstract
CpG islands recruit MLL1 via the CXXC domain to modulate chromatin structure and regulate gene expression. The amino acid motif of CXXC also plays a pivotal role in MLL1's structure and function and serves as a target for drug design. In addition, the CpG pattern in an island governs spatially dependent collaboration among CpGs in recruiting epigenetic enzymes. However, current studies using short DNA fragments cannot probe the dynamics of CXXC on long DNA with crowded CpG motifs. Here, we used single-molecule magnetic tweezers to examine the binding dynamics of MLL1's CXXC domain on a long DNA with a CpG island. The mechanical strand separation assay allows profiling of protein-DNA complexes and reports force-dependent unfolding times. Further design of a hairpin detector reveals the unfolding time of individual CXXC-CpG complexes. Finally, in a proof of concept we demonstrate the inhibiting effect of dimethyl fumarate on the CXXC-DNA complexes by measuring the dose response curve of the unfolding time. This demonstrates the potential feasibility of using single-molecule strand separation as a label-free detector in drug discovery and chemical biology.
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Affiliation(s)
- Lin Liang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Tianjin, China
| | - Kangkang Ma
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Tianjin, China
| | - Zeyu Wang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Tianjin, China
| | - Richard Janissen
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft, South-Holland, The Netherlands
| | - Zhongbo Yu
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Tianjin, China.
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18
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Redl E, Sheibani-Tezerji R, Cardona CDJ, Hamminger P, Timelthaler G, Hassler MR, Zrimšek M, Lagger S, Dillinger T, Hofbauer L, Draganić K, Tiefenbacher A, Kothmayer M, Dietz CH, Ramsahoye BH, Kenner L, Bock C, Seiser C, Ellmeier W, Schweikert G, Egger G. Requirement of DNMT1 to orchestrate epigenomic reprogramming for NPM-ALK-driven lymphomagenesis. Life Sci Alliance 2021; 4:e202000794. [PMID: 33310759 PMCID: PMC7768196 DOI: 10.26508/lsa.202000794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 11/28/2020] [Accepted: 12/01/2020] [Indexed: 12/31/2022] Open
Abstract
Malignant transformation depends on genetic and epigenetic events that result in a burst of deregulated gene expression and chromatin changes. To dissect the sequence of events in this process, we used a T-cell-specific lymphoma model based on the human oncogenic nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) translocation. We find that transformation of T cells shifts thymic cell populations to an undifferentiated immunophenotype, which occurs only after a period of latency, accompanied by induction of the MYC-NOTCH1 axis and deregulation of key epigenetic enzymes. We discover aberrant DNA methylation patterns, overlapping with regulatory regions, plus a high degree of epigenetic heterogeneity between individual tumors. In addition, ALK-positive tumors show a loss of associated methylation patterns of neighboring CpG sites. Notably, deletion of the maintenance DNA methyltransferase DNMT1 completely abrogates lymphomagenesis in this model, despite oncogenic signaling through NPM-ALK, suggesting that faithful maintenance of tumor-specific methylation through DNMT1 is essential for sustained proliferation and tumorigenesis.
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Affiliation(s)
- Elisa Redl
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | | | | | - Patricia Hamminger
- Division of Immunobiology, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Gerald Timelthaler
- Institute of Cancer Research, Medical University of Vienna, Vienna, Austria
| | - Melanie Rosalia Hassler
- Department of Pathology, Medical University of Vienna, Vienna, Austria
- Department of Urology, Medical University of Vienna, Vienna, Austria
| | - Maša Zrimšek
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | - Sabine Lagger
- Unit of Laboratory Animal Pathology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Thomas Dillinger
- Department of Pathology, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute Applied Diagnostics (LBI AD), Vienna, Austria
| | - Lorena Hofbauer
- Department of Pathology, Medical University of Vienna, Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Kristina Draganić
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | - Andreas Tiefenbacher
- Department of Pathology, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute Applied Diagnostics (LBI AD), Vienna, Austria
| | - Michael Kothmayer
- Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Charles H Dietz
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Bernard H Ramsahoye
- Centre for Genetic and Experimental Medicine, Institute of Genomic and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Lukas Kenner
- Department of Pathology, Medical University of Vienna, Vienna, Austria
- Unit of Laboratory Animal Pathology, University of Veterinary Medicine Vienna, Vienna, Austria
- Christian Doppler Laboratory for Applied Metabolomics (CDL-AM), Medical University of Vienna, Vienna, Austria
- Center for Biomarker Research in Medicine (CBmed), CoreLab 2, Medical University of Vienna, Vienna, Austria
| | - Christoph Bock
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Christian Seiser
- Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Wilfried Ellmeier
- Division of Immunobiology, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Gabriele Schweikert
- Max Planck Institute for Intelligent Systems, Tübingen, Germany
- Division of Computational Biology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Gerda Egger
- Department of Pathology, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute Applied Diagnostics (LBI AD), Vienna, Austria
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19
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Paredes-Céspedes DM, Rojas-García AE, Medina-Díaz IM, Ramos KS, Herrera-Moreno JF, Barrón-Vivanco BS, González-Arias CA, Bernal-Hernández YY. Environmental and socio-cultural impacts on global DNA methylation in the indigenous Huichol population of Nayarit, Mexico. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:4472-4487. [PMID: 32940839 DOI: 10.1007/s11356-020-10804-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
Alterations of global DNA methylation have been evaluated in several studies worldwide; however, Long Interspersed Nuclear Elements-1 (LINE-1) methylation in genetically conserved populations such as indigenous communities have not, to our knowledge, been reported. The aim of this study was to evaluate the relationship between LINE-1 methylation patterns and factors such as pesticide exposure and socio-cultural characteristics in the Indigenous Huichol Population of Nayarit, Mexico. A cross-sectional study was conducted in 140 Huichol indigenous individuals. A structured questionnaire was used to determine general and anthropometric characteristics, diet, harmful habits, and pesticide exposure. DNA methylation was determined by pyrosequencing of bisulfite-treated DNA. A lower level of LINE-1 methylation was found in the indigenous population when compared to a Mestizo population previously studied by our group. This difference might be due to the influence of the genetic admixture and differing dietary and lifestyle habits. The males in the indigenous population exhibited increased LINE-1 methylation in comparison to the females. Sex and alcohol consumption showed positive associations with LINE-1 methylation, while weight, current work in the field, current pesticide usage, and folate intake exhibited negative associations with LINE-1 methylation. The results suggest that ethnicity, as well as other internal and environmental factors, might influence LINE-1 methylation.
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Affiliation(s)
- Diana Marcela Paredes-Céspedes
- Posgrado en Ciencias Biológico Agropecuarias, Unidad Académica de Agricultura, Km. 9 Carretera Tepic-Compostela, Xalisco, Nayarit, México
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. C.P, 6300, Tepic, Nayarit, México
| | - Aurora Elizabeth Rojas-García
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. C.P, 6300, Tepic, Nayarit, México
| | - Irma Martha Medina-Díaz
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. C.P, 6300, Tepic, Nayarit, México
| | - Kenneth S Ramos
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, 121 W. Holcombe Blvd, Houston, TX, 77030 m EE,UU, USA
| | - José Francisco Herrera-Moreno
- Posgrado en Ciencias Biológico Agropecuarias, Unidad Académica de Agricultura, Km. 9 Carretera Tepic-Compostela, Xalisco, Nayarit, México
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. C.P, 6300, Tepic, Nayarit, México
| | - Briscia Socorro Barrón-Vivanco
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. C.P, 6300, Tepic, Nayarit, México
| | - Cyndia Azucena González-Arias
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. C.P, 6300, Tepic, Nayarit, México
| | - Yael Yvette Bernal-Hernández
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de la Cultura s/n. C.P, 6300, Tepic, Nayarit, México.
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20
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Olariu V, Yui MA, Krupinski P, Zhou W, Deichmann J, Andersson E, Rothenberg EV, Peterson C. Multi-scale Dynamical Modeling of T Cell Development from an Early Thymic Progenitor State to Lineage Commitment. Cell Rep 2021; 34:108622. [PMID: 33440162 DOI: 10.1016/j.celrep.2020.108622] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 04/24/2020] [Accepted: 12/18/2020] [Indexed: 01/13/2023] Open
Abstract
Intrathymic development of committed progenitor (pro)-T cells from multipotent hematopoietic precursors offers an opportunity to dissect the molecular circuitry establishing cell identity in response to environmental signals. This transition encompasses programmed shutoff of stem/progenitor genes, upregulation of T cell specification genes, proliferation, and ultimately commitment. To explain these features in light of reported cis-acting chromatin effects and experimental kinetic data, we develop a three-level dynamic model of commitment based upon regulation of the commitment-linked gene Bcl11b. The levels are (1) a core gene regulatory network (GRN) architecture from transcription factor (TF) perturbation data, (2) a stochastically controlled chromatin-state gate, and (3) a single-cell proliferation model validated by experimental clonal growth and commitment kinetic assays. Using RNA fluorescence in situ hybridization (FISH) measurements of genes encoding key TFs and measured bulk population dynamics, this single-cell model predicts state-switching kinetics validated by measured clonal proliferation and commitment times. The resulting multi-scale model provides a mechanistic framework for dissecting commitment dynamics.
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Affiliation(s)
- Victor Olariu
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Mary A Yui
- Division of Biology and Biological Engineering, 156-29, California Institute of Technology, Pasadena, CA 91125, USA
| | - Pawel Krupinski
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Wen Zhou
- Division of Biology and Biological Engineering, 156-29, California Institute of Technology, Pasadena, CA 91125, USA
| | - Julia Deichmann
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Emil Andersson
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Ellen V Rothenberg
- Division of Biology and Biological Engineering, 156-29, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Carsten Peterson
- Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden.
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21
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A Mathematical Model for Inheritance of DNA Methylation Patterns in Somatic Cells. Bull Math Biol 2020; 82:84. [PMID: 32613387 DOI: 10.1007/s11538-020-00765-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 06/10/2020] [Indexed: 12/22/2022]
Abstract
DNA methylation is an essential epigenetic mechanism used by cells to regulate gene expression. Interestingly, DNA replication, a function necessary for cell division, disrupts the methylation pattern. Since perturbed methylation patterns are associated with aberrant gene expression and many diseases, including cancer, restoration of the correct pattern following DNA replication is crucial. However, the exact mechanisms of this restoration remain under investigation. DNA methyltransferases (Dnmts) perform methylation by adding a methyl group to cytosines at CpG sites in the DNA. These CpG sites are found in regions of high density, termed CpG islands (CGIs), and regions of low density in the genome. Nearly, every CpG site in a CGI has the same state, either methylated or unmethylated, and almost all CpG sites in regions of low CpG density are methylated. We propose a stochastic model for the dynamics of the post-replicative restoration of methylation patterns. The model considers the recruitment of Dnmts and demethylating enzymes to regions of hyper- and hypomethylation, respectively. The model also includes the interaction between Dnmt1 and PCNA, an enzyme that localizes Dnmt1 to the replication complex. Using our model, we predict that the methylation of regions of DNA can be bistable. Further, we predict that recruitment mechanisms maintain methylation in CGIs, whereas the Dnmt1-PCNA interaction maintains methylation in low-density regions.
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22
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Lei J. A general mathematical framework for understanding the behavior of heterogeneous stem cell regeneration. J Theor Biol 2020; 492:110196. [PMID: 32067937 DOI: 10.1016/j.jtbi.2020.110196] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 12/28/2019] [Accepted: 02/11/2020] [Indexed: 11/21/2022]
Abstract
Stem cell heterogeneity is essential for homeostasis in tissue development. This paper establishes a general mathematical framework to model the dynamics of stem cell regeneration with cell heterogeneity and random transitions of epigenetic states. The framework generalizes the classical G0 cell cycle model and incorporates the epigenetic states of individual cells represented by a continuous multidimensional variable. In the model, the kinetic rates of cell behaviors, including proliferation, differentiation, and apoptosis, are dependent on their epigenetic states, and the random transitions of epigenetic states between cell cycles are represented by an inheritance probability function that describes the conditional probability of cell state changes. Moreover, the model can be extended to include genotypic changes and describe the process of gene mutation-induced tumor development. The proposed mathematical framework provides a generalized formula that helps us to understand various dynamic processes of stem cell regeneration, including tissue development, degeneration, and abnormal growth.
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Affiliation(s)
- Jinzhi Lei
- Zhou Pei-Yuan Center for Applied Mathematics, MOE Key Laboratory of Bioinformatics, Tsinghua University, Beijing 100084, China.
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23
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Ye Y, Yang Z, Lei J. DNA Methylation Heterogeneity Induced by Collaborations Between Enhancers. J Comput Biol 2020; 27:1668-1677. [PMID: 32311277 DOI: 10.1089/cmb.2019.0413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
During mammalian embryo development, reprogramming of DNA methylation plays important roles in the erasure of parental epigenetic memory and the establishment of naive pluripotent cells. Multiple enzymes that regulate the processes of methylation and demethylation work together to shape the pattern of genome-scale DNA methylation and guide the process of cell differentiation. Recent availability of methylome information from single-cell whole genome bisulfite sequencing (scBS-seq) provides an opportunity to study DNA methylation dynamics in the whole genome in individual cells, which reveal the heterogeneous methylation distributions of enhancers in embryo stem cells. In this study, we developed a computational model of enhancer methylation inheritance to study the dynamics of genome-scale DNA methylation reprogramming during exit from pluripotency. The model enables us to track genome-scale DNA methylation reprogramming at single-cell level during the embryo development process and reproduce the DNA methylation heterogeneity reported by scBS-seq. Model simulations show that DNA methylation heterogeneity is an intrinsic property driven by cell division along the development process, and the collaboration between neighboring enhancers is required for heterogeneous methylation. Our study suggests that the mechanism of genome-scale oscillation might not be necessary for the DNA methylation heterogeneity during exit from pluripotency.
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Affiliation(s)
- Yusong Ye
- School of Mathematics and Systems Science and LMIB, Beihang University, Beijing, China
| | - Zhuoqin Yang
- School of Mathematics and Systems Science and LMIB, Beihang University, Beijing, China
| | - Jinzhi Lei
- Zhou Pei-Yuan Center for Applied Mathematics, MOE Key Laboratory of Bioinformatics, Tsinghua University, Beijing, China
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24
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Busto-Moner L, Morival J, Ren H, Fahim A, Reitz Z, Downing TL, Read EL. Stochastic modeling reveals kinetic heterogeneity in post-replication DNA methylation. PLoS Comput Biol 2020; 16:e1007195. [PMID: 32275652 PMCID: PMC7176288 DOI: 10.1371/journal.pcbi.1007195] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 04/22/2020] [Accepted: 01/20/2020] [Indexed: 01/17/2023] Open
Abstract
DNA methylation is a heritable epigenetic modification that plays an essential role in mammalian development. Genomic methylation patterns are dynamically maintained, with DNA methyltransferases mediating inheritance of methyl marks onto nascent DNA over cycles of replication. A recently developed experimental technique employing immunoprecipitation of bromodeoxyuridine labeled nascent DNA followed by bisulfite sequencing (Repli-BS) measures post-replication temporal evolution of cytosine methylation, thus enabling genome-wide monitoring of methylation maintenance. In this work, we combine statistical analysis and stochastic mathematical modeling to analyze Repli-BS data from human embryonic stem cells. We estimate site-specific kinetic rate constants for the restoration of methyl marks on >10 million uniquely mapped cytosines within the CpG (cytosine-phosphate-guanine) dinucleotide context across the genome using Maximum Likelihood Estimation. We find that post-replication remethylation rate constants span approximately two orders of magnitude, with half-lives of per-site recovery of steady-state methylation levels ranging from shorter than ten minutes to five hours and longer. Furthermore, we find that kinetic constants of maintenance methylation are correlated among neighboring CpG sites. Stochastic mathematical modeling provides insight to the biological mechanisms underlying the inference results, suggesting that enzyme processivity and/or collaboration can produce the observed kinetic correlations. Our combined statistical/mathematical modeling approach expands the utility of genomic datasets and disentangles heterogeneity in methylation patterns arising from replication-associated temporal dynamics versus stable cell-to-cell differences.
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Affiliation(s)
- Luis Busto-Moner
- Institut Químic de Sarrià, Universitat Ramon Llull, Barcelona, Spain
- Dept. of Chemical & Biomolecular Engineering, University of California, Irvine, California, United States of America
| | - Julien Morival
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States of America
| | - Honglei Ren
- NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, Irvine, California, United States of America
| | - Arjang Fahim
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States of America
| | - Zachary Reitz
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States of America
| | - Timothy L. Downing
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States of America
- NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, Irvine, California, United States of America
- Center for Complex Biological Systems, University of California, Irvine, Irvine, California, United States of America
| | - Elizabeth L. Read
- Dept. of Chemical & Biomolecular Engineering, University of California, Irvine, California, United States of America
- NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, Irvine, California, United States of America
- Center for Complex Biological Systems, University of California, Irvine, Irvine, California, United States of America
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Shridhar V, Chu T, Simhan H, Shaw PA, Peters DG. High‐resolution analysis of the human placental DNA methylome in early gestation. Prenat Diagn 2020; 40:481-491. [DOI: 10.1002/pd.5618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 09/27/2019] [Accepted: 10/09/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Varsha Shridhar
- Department of Obstetrics, Gynecology and Reproductive SciencesUniversity of Pittsburgh Pittsburgh Pennsylvania
- Magee‐Womens Research Institute Pittsburgh Pennsylvania
| | - Tianjiao Chu
- Department of Obstetrics, Gynecology and Reproductive SciencesUniversity of Pittsburgh Pittsburgh Pennsylvania
- Magee‐Womens Research Institute Pittsburgh Pennsylvania
| | - Hyagriv Simhan
- Department of Obstetrics, Gynecology and Reproductive SciencesUniversity of Pittsburgh Pittsburgh Pennsylvania
- Magee‐Womens Research Institute Pittsburgh Pennsylvania
| | | | - David G. Peters
- Department of Obstetrics, Gynecology and Reproductive SciencesUniversity of Pittsburgh Pittsburgh Pennsylvania
- Magee‐Womens Research Institute Pittsburgh Pennsylvania
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Inter-laboratory adaption of age estimation models by DNA methylation analysis—problems and solutions. Int J Legal Med 2020; 134:953-961. [DOI: 10.1007/s00414-020-02263-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 01/31/2020] [Indexed: 12/24/2022]
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DNA sequence context as a marker of CpG methylation instability in normal and cancer tissues. Sci Rep 2020; 10:1721. [PMID: 32015379 PMCID: PMC6997448 DOI: 10.1038/s41598-020-58331-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 01/13/2020] [Indexed: 11/09/2022] Open
Abstract
DNA methylation alterations are related to multiple molecular mechanisms. The DNA context of CpG sites plays a crucial role in the maintenance and stability of methylation patterns. The quantitative relationship between DNA composition and DNA methylation has been studied in normal as well as pathological conditions, showing that DNA methylation status is highly dependent on the local sequence context. In this work, we describe this relationship by analyzing the DNA sequence context associated to methylation profiles in both physiological and pathological conditions. In particular, we used DNA motifs to describe methylation stability patterns in normal tissues and aberrant methylation events in cancer lesions. In this manuscript, we show how different groups of DNA sequences can be related to specific epigenetic events, across normal and cancer tissues, and provide a thorough structural and functional characterization of these sequences.
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Genome-Scale Oscillations in DNA Methylation during Exit from Pluripotency. Cell Syst 2019; 7:63-76.e12. [PMID: 30031774 PMCID: PMC6066359 DOI: 10.1016/j.cels.2018.06.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 10/17/2017] [Accepted: 06/25/2018] [Indexed: 12/22/2022]
Abstract
Pluripotency is accompanied by the erasure of parental epigenetic memory, with naïve pluripotent cells exhibiting global DNA hypomethylation both in vitro and in vivo. Exit from pluripotency and priming for differentiation into somatic lineages is associated with genome-wide de novo DNA methylation. We show that during this phase, co-expression of enzymes required for DNA methylation turnover, DNMT3s and TETs, promotes cell-to-cell variability in this epigenetic mark. Using a combination of single-cell sequencing and quantitative biophysical modeling, we show that this variability is associated with coherent, genome-scale oscillations in DNA methylation with an amplitude dependent on CpG density. Analysis of parallel single-cell transcriptional and epigenetic profiling provides evidence for oscillatory dynamics both in vitro and in vivo. These observations provide insights into the emergence of epigenetic heterogeneity during early embryo development, indicating that dynamic changes in DNA methylation might influence early cell fate decisions. Co-expression of DNMT3s and TETs promotes genome-scale oscillations in DNA methylation Oscillation amplitude is greatest at a CpG density characteristic of enhancers Cell synchronization reveals oscillation period and link with primary transcripts Multi-omic single-cell profiling provides evidence for oscillatory dynamics in vivo
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Barazandeh A, Mohammadabadi M, Ghaderi-Zefrehei M, Rafeie F, Imumorin IG. Whole genome comparative analysis of CpG islands in camelid and other mammalian genomes. Mamm Biol 2019. [DOI: 10.1016/j.mambio.2019.07.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Luck A, Giehr P, Nordstrom K, Walter J, Wolf V. Hidden Markov Modelling Reveals Neighborhood Dependence of Dnmt3a and 3b Activity. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2019; 16:1598-1609. [PMID: 31027045 DOI: 10.1109/tcbb.2019.2910814] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
DNA methylation is an epigenetic mark whose important role in development has been widely recognized. This epigenetic modification results in heritable information not encoded by the DNA sequence. The underlying mechanisms controlling DNA methylation are only partly understood. Several mechanistic models of enzyme activities responsible for DNA methylation have been proposed. Here, we extend existing Hidden Markov Models (HMMs) for DNA methylation by describing the occurrence of spatial methylation patterns over time and propose several models with different neighborhood dependences. Furthermore, we investigate correlations between the neighborhood dependence and other genomic information. We perform numerical analysis of the HMMs applied to comprehensive hairpin and non-hairpin bisulfite sequencing measurements and accurately predict wild-type data. We find evidence that the activities of Dnmt3a and Dnmt3b responsible for de novo methylation depend on 5' (left) but not on 3' (right) neighboring CpGs in a sequencing string.
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Lei J, Nie Q, Chen DB. A single-cell epigenetic model for paternal psychological stress-induced transgenerational reprogramming in offspring. Biol Reprod 2019; 98:846-855. [PMID: 29506130 DOI: 10.1093/biolre/ioy050] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 02/25/2018] [Indexed: 12/16/2022] Open
Abstract
Experimental evidence shows that parental psychological stress affects the long-term health of offspring in an inheritable fashion. Although epigenetic mechanisms, including DNA methylation, miRNA, and histone modifications, are involved in transgenerational programming, the underlining mechanisms of transgenerational inheritance remain unsolved. Here, we present a single-cell-based computational model for transgenerational inheritance for investigating the long-term dynamics of phenotype changes in response to parental stress. The model is based on a recent study that has identified the imprinted sperm gene Sfmbt2 as a key target, and incorporates crosstalks among drastically different time scales in mammalian development, including DNA methylation, transcription, cell division, and population dynamics. Computational analysis of the model suggests a positive feedback to DNA methylation in the promoter region of sperm Sfmbt2 gene that provides a possible mechanism to mediate the parental psychological stress reprogramming in offspring. This approach provides a modeling framework for the understanding of the roles that epigenetics play in transgenerational inheritance.
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Affiliation(s)
- Jinzhi Lei
- Zhou Pei-Yuan Center for Applied Mathematics, MOE Key Laboratory of Bioinformatics, Tsinghua University, Beijing, China
| | - Qing Nie
- Department of Mathematics, Department of Developmental and Cell Biology, Center for Mathematical and Computational Biology, University of California, Irvine, Irvine, California, USA
| | - Dong-Bao Chen
- Department of Obstetrics and Gynecology, University of California Irvine, Irvine, California, USA
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Affinito O, Palumbo D, Fierro A, Cuomo M, De Riso G, Monticelli A, Miele G, Chiariotti L, Cocozza S. Nucleotide distance influences co-methylation between nearby CpG sites. Genomics 2019; 112:144-150. [PMID: 31078719 DOI: 10.1016/j.ygeno.2019.05.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/18/2019] [Accepted: 05/08/2019] [Indexed: 12/31/2022]
Abstract
The tendency of individual CpG sites to be methylated is distinctive, non-random and well-regulated throughout the genome. We investigated the structural and spatial factors influencing CpGs methylation by performing an ultra-deep targeted methylation analysis on human, mouse and zebrafish genes. We found that methylation is not a random process and that closer neighboring CpG sites are more likely to share the same methylation status. Moreover, if the distance between CpGs increases, the degree of co-methylation decreases. We set up a simulation model to analyze the contribution of both the intrinsic susceptibility and the distance effect on the probability of a CpG to be methylated. Our finding suggests that the establishment of a specific methylation pattern follows a universal rule that must take into account of the synergistic and dynamic interplay of these two main factors: the intrinsic methylation susceptibility of specific CpG and the nucleotide distance between two CpG sites.
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Affiliation(s)
- Ornella Affinito
- Istituto di Endocrinologia ed Oncologia Sperimentale (IEOS) "Gaetano Salvatore", Consiglio Nazionale delle Ricerche (CNR), Naples, Italy; Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Via S. Pansini 5, 80131 Naples, Italy.
| | - Domenico Palumbo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Via S. Pansini 5, 80131 Naples, Italy
| | - Annalisa Fierro
- CNR-SPIN, c/o Complesso di Monte S. Angelo, via Cinthia, 80126 Napoli, Italy
| | - Mariella Cuomo
- Istituto di Endocrinologia ed Oncologia Sperimentale (IEOS) "Gaetano Salvatore", Consiglio Nazionale delle Ricerche (CNR), Naples, Italy; Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Via S. Pansini 5, 80131 Naples, Italy
| | - Giulia De Riso
- Istituto di Endocrinologia ed Oncologia Sperimentale (IEOS) "Gaetano Salvatore", Consiglio Nazionale delle Ricerche (CNR), Naples, Italy; Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Via S. Pansini 5, 80131 Naples, Italy
| | - Antonella Monticelli
- Istituto di Endocrinologia ed Oncologia Sperimentale (IEOS) "Gaetano Salvatore", Consiglio Nazionale delle Ricerche (CNR), Naples, Italy
| | - Gennaro Miele
- Dipartimento di Fisica "E. Pancini", Università degli Studi di Napoli "Federico II", Naples, Italy
| | - Lorenzo Chiariotti
- Istituto di Endocrinologia ed Oncologia Sperimentale (IEOS) "Gaetano Salvatore", Consiglio Nazionale delle Ricerche (CNR), Naples, Italy; Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Via S. Pansini 5, 80131 Naples, Italy; Dipartimento di Farmacia, Università degli Studi di Napoli "Federico II", Naples, Italy
| | - Sergio Cocozza
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli "Federico II", Via S. Pansini 5, 80131 Naples, Italy
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Abstract
Background DNA methylation is an epigenetic event that may regulate gene expression. Because of this regulation role, aberrant DNA methylation is often associated with many diseases. Within-sample DNA co-methylation is the similarity of methylation in nearby cytosine sites of a chromosome. It is important to study co-methylation patterns. However, it is not well studied yet, and it is unclear to us what co-methylation patterns normal DNA samples have. Are the co-methylation patterns of the same tissue across several samples different? Are the co-methylation patterns of various tissues of the same sample different? To answer these questions, we conduct analyses using two sets of data: 3-sample-1-tissue (3S1T) and 1-sample-8-tissue (1S8T). Results To study the co-methylation patterns of the two datasets, 3S1T and 1S8T, we investigate the following questions: How often does one methylation state change to other methylation states and how is this change associated with chromosome distance? Based on the 3S1T data, we find there is not significant co-methylation difference among the same spleen tissues of three different samples. However, the analysis results of 1S8T data show that there were significant differences among eight tissues of one sample. For both 3S1T and 1S8T data, we find that the no/low methylation state A and high/full methylation state D tend to remain the same along a chromosome region. We also find that the low/partial methylation state B and partial/high methylation state C tend to change to higher methylation states along a chromosome. Finally, we find that lengths of most co-methylation regions are very short with only a few hundred base pairs. In fact, only a small proportion of methylated regions are longer than 1000 base pairs. Conclusions In this paper, we have addressed a few questions regarding within-sample co-methylation patterns in normal tissues. Our statistical analysis results and answers may help researchers to better understand the biological process of DNA methylation. This may pave the way to develop better analysis methods for future methylation research. Electronic supplementary material The online version of this article (10.1186/s13040-019-0198-8) contains supplementary material, which is available to authorized users.
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Mc Auley MT, Mooney KM, Salcedo-Sora JE. Computational modelling folate metabolism and DNA methylation: implications for understanding health and ageing. Brief Bioinform 2019; 19:303-317. [PMID: 28007697 DOI: 10.1093/bib/bbw116] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Indexed: 11/12/2022] Open
Abstract
Dietary folates have a key role to play in health, as deficiencies in the intake of these B vitamins have been implicated in a wide variety of clinical conditions. The reason for this is folates function as single carbon donors in the synthesis of methionine and nucleotides. Moreover, folates have a vital role to play in the epigenetics of mammalian cells by supplying methyl groups for DNA methylation reactions. Intriguingly, a growing body of experimental evidence suggests that DNA methylation status could be a central modulator of the ageing process. This has important health implications because the methylation status of the human genome could be used to infer age-related disease risk. Thus, it is imperative we further our understanding of the processes which underpin DNA methylation and how these intersect with folate metabolism and ageing. The biochemical and molecular mechanisms, which underpin these processes, are complex. However, computational modelling offers an ideal framework for handling this complexity. A number of computational models have been assembled over the years, but to date, no model has represented the full scope of the interaction between the folate cycle and the reactions, which governs the DNA methylation cycle. In this review, we will discuss several of the models, which have been developed to represent these systems. In addition, we will present a rationale for developing a combined model of folate metabolism and the DNA methylation cycle.
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Affiliation(s)
- Mark T Mc Auley
- Department of Chemical Engineering, Thornton Science Park, University of Chester, UK
| | - Kathleen M Mooney
- Faculty of Health and Social Care, Edge Hill University, Ormskirk, Lancashire, UK
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Zagkos L, Auley MM, Roberts J, Kavallaris NI. Mathematical models of DNA methylation dynamics: Implications for health and ageing. J Theor Biol 2019; 462:184-193. [DOI: 10.1016/j.jtbi.2018.11.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 11/01/2018] [Accepted: 11/09/2018] [Indexed: 12/24/2022]
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Larson K, Zagkos L, Mc Auley M, Roberts J, Kavallaris NI, Matzavinos A. Data-driven selection and parameter estimation for DNA methylation mathematical models. J Theor Biol 2019; 467:87-99. [PMID: 30633883 DOI: 10.1016/j.jtbi.2019.01.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 12/18/2018] [Accepted: 01/08/2019] [Indexed: 11/27/2022]
Abstract
Epigenetics is coming to the fore as a key process which underpins health. In particular emerging experimental evidence has associated alterations to DNA methylation status with healthspan and aging. Mammalian DNA methylation status is maintained by an intricate array of biochemical and molecular processes. It can be argued changes to these fundamental cellular processes ultimately drive the formation of aberrant DNA methylation patterns, which are a hallmark of diseases, such as cancer, Alzheimer's disease and cardiovascular disease. In recent years mathematical models have been used as effective tools to help advance our understanding of the dynamics which underpin DNA methylation. In this paper we present linear and nonlinear models which encapsulate the dynamics of the molecular mechanisms which define DNA methylation. Applying a recently developed Bayesian algorithm for parameter estimation and model selection, we are able to estimate distributions of parameters which include nominal parameter values. Using limited noisy observations, the method also identified which methylation model the observations originated from, signaling that our method has practical applications in identifying what models best match the biological data for DNA methylation.
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Affiliation(s)
- Karen Larson
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA
| | - Loukas Zagkos
- Department of Mathematics, School of Science and Engineering, University of Chester, Thornton Science Park, Pool Lane, Ince, Chester CH2 4NU, UK
| | - Mark Mc Auley
- Department of Chemical Engineering, School of Science and Engineering, University of Chester, Thornton Science Park, Pool Lane, Ince, Chester CH2 4NU, UK
| | - Jason Roberts
- Department of Mathematics, School of Science and Engineering, University of Chester, Thornton Science Park, Pool Lane, Ince, Chester CH2 4NU, UK
| | - Nikos I Kavallaris
- Department of Mathematics, School of Science and Engineering, University of Chester, Thornton Science Park, Pool Lane, Ince, Chester CH2 4NU, UK
| | - Anastasios Matzavinos
- Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912, USA.
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Duis J, Cox OH, Ji Y, Seifuddin F, Lee RS, Wang X. Effect of Genotype and Maternal Affective Disorder on Intronic Methylation of FK506 Binding Protein 5 in Cord Blood DNA. Front Genet 2018; 9:648. [PMID: 30619472 PMCID: PMC6305129 DOI: 10.3389/fgene.2018.00648] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 11/30/2018] [Indexed: 12/20/2022] Open
Abstract
A single nucleotide polymorphism (SNP: rs1360780) in FKBP5 (FK506 Binding Protein 5) has been shown to interact with exposure to childhood adversity to promote loss of methylation and increase in gene expression in adults. We asked whether rs1360780 can influence FKBP5 intronic methylation in the context of exposure to maternal affective disorders in utero. Sixty cord blood DNA samples from the Boston Birth Cohort were genotyped at rs1360780 and studied for methylation changes as they relate to genotype and exposure to affective disorders during pregnancy. Linear regression was employed to contrast the risk (TT) genotype to the heterozygous (CT) and homozygous (CC) genotypes with adjustment for potential confounders. The recessive genotype (TT) was associated with increased methylation at multiple CpGs in the FKBP5 intron 5 region (p < 0.01). These findings were enhanced among cases exposed to maternal affective disorders (p = 0.02). A human cell line treated with cortisol showed that changes in intron 5 CpG methylation and FKBP5 expression were inversely associated. These findings suggest that rs1360780 can influence FKBP5 intronic methylation by acting in cis as a methylation quantitative locus and highlight the impact of genotypic risk on methylation in utero. Additionally, prenatal stress exposure compounded with the risk genotype may lead to a compensatory increase in methylation.
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Affiliation(s)
- Jessica Duis
- Division of Medical Genetics and Genomic Medicine, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Olivia H Cox
- Department of Psychiatry and Behavioral Sciences, Mood Disorders Center, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Yuelong Ji
- Department of Population, Family and Reproductive Health, Center on the Early Life Origins of Disease, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, United States
| | - Fayaz Seifuddin
- Department of Psychiatry and Behavioral Sciences, Mood Disorders Center, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Richard S Lee
- Department of Psychiatry and Behavioral Sciences, Mood Disorders Center, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Xiaobin Wang
- Department of Mental Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, United States
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Naue J, Sänger T, Hoefsloot HCJ, Lutz-Bonengel S, Kloosterman AD, Verschure PJ. Proof of concept study of age-dependent DNA methylation markers across different tissues by massive parallel sequencing. Forensic Sci Int Genet 2018; 36:152-159. [PMID: 30031222 DOI: 10.1016/j.fsigen.2018.07.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 07/03/2018] [Accepted: 07/06/2018] [Indexed: 12/20/2022]
Abstract
The use of DNA methylation (DNAm) for chronological age determination has been widely investigated within the last few years for its application within the field of forensic genetics. The majority of forensic studies are based on blood, saliva, and buccal cell samples, respectively. Although these types of samples represent an extensive amount of traces found at a crime scene or are readily available from individuals, samples from other tissues can be relevant for forensic investigations. Age determination could be important for cases involving unidentifiable bodies and based on remaining soft tissue e.g. brain and muscle, or completely depend on hard tissue such as bone. However, due to the cell type specificity of DNAm, it is not evident whether cell type specific age-dependent CpG positions are also applicable for age determination in other cell types. Within this pilot study, we investigated whether 13 previously selected age-dependent loci based on whole blood analysis including amongst others ELOVL2, TRIM59, F5, and KLF14 also have predictive value in other forensically relevant tissues. Samples of brain, bone, muscle, buccal swabs, and whole blood of 29 deceased individuals (age range 0-87 years) were analyzed for these 13 age-dependent markers using massive parallel sequencing. Seven of these loci did show age-dependency in all five tissues. The change of DNAm during lifetime was different in the set of tissues analyzed, and sometimes other CpG sites within the loci showed a higher age-dependency. This pilot study shows the potential of existing blood DNAm markers for age-determination to analyze other tissues than blood. We identified seven known blood-based DNAm markers for use in muscle, brain, bone, buccal swabs, and blood. Nevertheless, a different reference set for each tissue is needed to adapt for tissue-specific changes of the DNAm over time.
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Affiliation(s)
- Jana Naue
- University of Amsterdam, Swammerdam Institute for Life Sciences, Science Park 904, 1098XH Amsterdam, The Netherlands; Institute of Forensic Medicine, Medical Center - University of Freiburg, Forensic Molecular Biology, Alberstrasse 9, 79104 Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Timo Sänger
- Institute of Forensic Medicine, Medical Center - University of Freiburg, Forensic Molecular Biology, Alberstrasse 9, 79104 Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Huub C J Hoefsloot
- University of Amsterdam, Swammerdam Institute for Life Sciences, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - Sabine Lutz-Bonengel
- Institute of Forensic Medicine, Medical Center - University of Freiburg, Forensic Molecular Biology, Alberstrasse 9, 79104 Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ate D Kloosterman
- Netherlands Forensic Institute, Biological Traces, Laan van Ypenburg 6, 2497GB Den Haag, The Netherlands; University of Amsterdam, Institute for Biodiversity and Dynamics, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - Pernette J Verschure
- University of Amsterdam, Swammerdam Institute for Life Sciences, Science Park 904, 1098XH Amsterdam, The Netherlands.
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Meyer KN, Lacey MR. Modeling Methylation Patterns with Long Read Sequencing Data. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2018; 15:1379-1389. [PMID: 28682263 DOI: 10.1109/tcbb.2017.2721943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Variation in cytosine methylation at CpG dinucleotides is often observed in genomic regions, and analysis typically focuses on estimating the proportion of methylated sites observed in a given region and comparing these levels across samples to determine association with conditions of interest. While sites are tacitly treated as independent, when observed at the level of individual molecules methylation patterns exhibit strong evidence of local spatial dependence. We previously developed a neighboring sites model to account for correlation and clustering behavior observed in two tandem repeat regions in a collection of ovarian carcinomas. We now introduce extensions of the model that account for the effect of distance between sites as well as asymmetric correlation in de novo methylation and demethylation rates. We apply our models to published data from a whole genome bisulfite sequencing experiment using long reads, estimating model parameters for a selection of CpG-dense regions spanning between 21 and 67 sites. Our methods detect evidence of local spatial correlation as a function of site-to-site distance and demonstrate the added value of employing long read sequencing data in epigenetic research.
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40
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Lövkvist C, Sneppen K, Haerter JO. Exploring the Link between Nucleosome Occupancy and DNA Methylation. Front Genet 2018; 8:232. [PMID: 29379519 PMCID: PMC5771128 DOI: 10.3389/fgene.2017.00232] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/22/2017] [Indexed: 12/21/2022] Open
Abstract
Near promoters, both nucleosomes and CpG sites form characteristic spatial patterns. Previously, nucleosome depleted regions were observed upstream of transcription start sites and nucleosome occupancy was reported to correlate both with CpG density and the level of CpG methylation. Several studies imply a causal link where CpG methylation might induce nucleosome formation, whereas others argue the opposite, i.e., that nucleosome occupancy might influence CpG methylation. Correlations are indeed evident between nucleosomes, CpG density and CpG methylation—at least near promoter sites. It is however less established whether there is an immediate causal relation between nucleosome occupancy and the presence of CpG sites—or if nucleosome occupancy could be influenced by other factors. In this work, we test for such causality in human genomes by analyzing the three quantities both near and away from promoter sites. For data from the human genome we compare promoter regions with given CpG densities with genomic regions without promoters but of similar CpG densities. We find the observed correlation between nucleosome occupancy and CpG density, respectively CpG methylation, to be specific to promoter regions. In other regions along the genome nucleosome occupancy is statistically independent of the positioning of CpGs or their methylation levels. Anti-correlation between CpG density and methylation level is however similarly strong in both regions. On promoters, nucleosome occupancy is more strongly affected by the level of gene expression than CpG density or CpG methylation—calling into question any direct causal relation between nucleosome occupancy and CpG organization. Rather, our results suggest that for organisms with cytosine methylation nucleosome occupancy might be primarily linked to gene expression, with no strong impact on methylation.
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Affiliation(s)
- Cecilia Lövkvist
- Center for Models of Life, Niels Bohr Institue, University of Copenhagen, Copenhagen, Denmark
| | - Kim Sneppen
- Center for Models of Life, Niels Bohr Institue, University of Copenhagen, Copenhagen, Denmark
| | - Jan O Haerter
- Center for Models of Life, Niels Bohr Institue, University of Copenhagen, Copenhagen, Denmark
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41
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Abstract
The question of how noncoding RNAs are involved in Polycomb group (PcG) and Trithorax group (TrxG) regulation has been on an extraordinary journey over the last three decades. Favored models have risen and fallen, and healthy debates have swept back and forth. The field has recently reached a critical mass of compelling data that throws light on several previously unresolved issues. The time is ripe for a fruitful combination of these findings with two other long-running avenues of research, namely the biochemical properties of the PcG/TrxG system and the application of theoretical mathematical models toward an understanding of the system's regulatory properties. I propose that integrating our current knowledge of noncoding RNA into a quantitative biochemical and theoretical framework for PcG and TrxG regulation has the potential to reconcile several apparently conflicting models and identifies fascinating questions for future research.
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Affiliation(s)
- Leonie Ringrose
- Integrated Research Institute for Life Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany;
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42
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Dissecting chromatin-mediated gene regulation and epigenetic memory through mathematical modelling. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.coisb.2017.02.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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43
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Haerter JO, Díaz-Guilera A, Serrano MÁ. Noise-induced polarization switching in complex networks. Phys Rev E 2017; 95:042305. [PMID: 28505785 DOI: 10.1103/physreve.95.042305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Indexed: 11/07/2022]
Abstract
The combination of bistability and noise is ubiquitous in complex systems, from biology to social interactions, and has important implications for their functioning and resilience. Here we use a simple three-state dynamical process, in which nodes go from one pole to another through an intermediate state, to show that noise can induce polarization switching in bistable systems if dynamical correlations are significant. In large, fully connected networks, where dynamical correlations can be neglected, increasing noise yields a collapse of bistability to an unpolarized configuration where the three possible states of the nodes are equally likely. In contrast, increased noise induces abrupt and irreversible polarization switching in sparsely connected networks. In multiplexes, where each layer can have a different polarization tendency, one layer is dominant and progressively imposes its polarization state on the other, offsetting or promoting the ability of noise to switch its polarization. Overall, we show that the interplay of noise and dynamical correlations can yield discontinuous transitions between extremes, which cannot be explained by a simple mean-field description.
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Affiliation(s)
- Jan O Haerter
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.,Niels Bohr Institutet, Københavns Universitet, Blegdamsvej 17, 2100 København Ø, Denmark
| | - Albert Díaz-Guilera
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.,Universitat de Barcelona Institute of Complex Systems (UBICS), Universitat de Barcelona, Barcelona, Spain
| | - M Ángeles Serrano
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.,Universitat de Barcelona Institute of Complex Systems (UBICS), Universitat de Barcelona, Barcelona, Spain.,ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
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44
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Sneppen K. Models of life: epigenetics, diversity and cycles. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:042601. [PMID: 28106010 DOI: 10.1088/1361-6633/aa5aeb] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This review emphasizes aspects of biology that can be understood through repeated applications of simple causal rules. The selected topics include perspectives on gene regulation, phage lambda development, epigenetics, microbial ecology, as well as model approaches to diversity and to punctuated equilibrium in evolution. Two outstanding features are repeatedly described. One is the minimal number of rules to sustain specific states of complex systems for a long time. The other is the collapse of such states and the subsequent dynamical cycle of situations that restitute the system to a potentially new metastable state.
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Affiliation(s)
- Kim Sneppen
- Center for Models of Life, Niels Bohr Institute, Blegdamsvej 17, 2100 Copenhagen, Denmark
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45
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Arabidopsis male sexual lineage exhibits more robust maintenance of CG methylation than somatic tissues. Proc Natl Acad Sci U S A 2016; 113:15132-15137. [PMID: 27956643 DOI: 10.1073/pnas.1619074114] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Cytosine DNA methylation regulates the expression of eukaryotic genes and transposons. Methylation is copied by methyltransferases after DNA replication, which results in faithful transmission of methylation patterns during cell division and, at least in flowering plants, across generations. Transgenerational inheritance is mediated by a small group of cells that includes gametes and their progenitors. However, methylation is usually analyzed in somatic tissues that do not contribute to the next generation, and the mechanisms of transgenerational inheritance are inferred from such studies. To gain a better understanding of how DNA methylation is inherited, we analyzed purified Arabidopsis thaliana sperm and vegetative cells-the cell types that comprise pollen-with mutations in the DRM, CMT2, and CMT3 methyltransferases. We find that DNA methylation dependency on these enzymes is similar in sperm, vegetative cells, and somatic tissues, although DRM activity extends into heterochromatin in vegetative cells, likely reflecting transcription of heterochromatic transposons in this cell type. We also show that lack of histone H1, which elevates heterochromatic DNA methylation in somatic tissues, does not have this effect in pollen. Instead, levels of CG methylation in wild-type sperm and vegetative cells, as well as in wild-type microspores from which both pollen cell types originate, are substantially higher than in wild-type somatic tissues and similar to those of H1-depleted roots. Our results demonstrate that the mechanisms of methylation maintenance are similar between pollen and somatic cells, but the efficiency of CG methylation is higher in pollen, allowing methylation patterns to be accurately inherited across generations.
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46
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Affinito O, Scala G, Palumbo D, Florio E, Monticelli A, Miele G, Avvedimento VE, Usiello A, Chiariotti L, Cocozza S. Modeling DNA methylation by analyzing the individual configurations of single molecules. Epigenetics 2016; 11:881-888. [PMID: 27748645 DOI: 10.1080/15592294.2016.1246108] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
DNA methylation is often analyzed by reporting the average methylation degree of each cytosine. In this study, we used a single molecule methylation analysis in order to look at the methylation conformation of individual molecules. Using D-aspartate oxidase as a model gene, we performed an in-depth methylation analysis through the developmental stages of 3 different mouse tissues (brain, lung, and gut), where this gene undergoes opposite methylation destiny. This approach allowed us to track both methylation and demethylation processes at high resolution. The complexity of these dynamics was markedly simplified by introducing the concept of methylation classes (MCs), defined as the number of methylated cytosines per molecule, irrespective of their position. The MC concept smooths the stochasticity of the system, allowing a more deterministic description. In this framework, we also propose a mathematical model based on the Markov chain. This model aims to identify the transition probability of a molecule from one MC to another during methylation and demethylation processes. The results of our model suggest that: 1) both processes are ruled by a dominant class of phenomena, namely, the gain or loss of one methyl group at a time; and 2) the probability of a single CpG site becoming methylated or demethylated depends on the methylation status of the whole molecule at that time.
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Affiliation(s)
- Ornella Affinito
- a Istituto di Endocrinologia ed Oncologia Sperimentale (IEOS) "Gaetano Salvatore ," Consiglio Nazionale delle Ricerche (CNR) , Naples , Italy.,b Dipartimento di Medicina Molecolare e Biotecnologie Mediche , Università degli Studi di Napoli "Federico II ," Naples , Italy
| | - Giovanni Scala
- c Istituto Nazionale di Fisica Nucleare , Sezione di Napoli , Naples , Italy
| | - Domenico Palumbo
- b Dipartimento di Medicina Molecolare e Biotecnologie Mediche , Università degli Studi di Napoli "Federico II ," Naples , Italy
| | - Ermanno Florio
- a Istituto di Endocrinologia ed Oncologia Sperimentale (IEOS) "Gaetano Salvatore ," Consiglio Nazionale delle Ricerche (CNR) , Naples , Italy.,b Dipartimento di Medicina Molecolare e Biotecnologie Mediche , Università degli Studi di Napoli "Federico II ," Naples , Italy
| | - Antonella Monticelli
- a Istituto di Endocrinologia ed Oncologia Sperimentale (IEOS) "Gaetano Salvatore ," Consiglio Nazionale delle Ricerche (CNR) , Naples , Italy
| | - Gennaro Miele
- c Istituto Nazionale di Fisica Nucleare , Sezione di Napoli , Naples , Italy.,d Dipartimento di Fisica , Università degli Studi di Napoli "Federico II ," Naples , Italy
| | - Vittorio Enrico Avvedimento
- a Istituto di Endocrinologia ed Oncologia Sperimentale (IEOS) "Gaetano Salvatore ," Consiglio Nazionale delle Ricerche (CNR) , Naples , Italy.,b Dipartimento di Medicina Molecolare e Biotecnologie Mediche , Università degli Studi di Napoli "Federico II ," Naples , Italy
| | - Alessandro Usiello
- e CEINGE Biotecnologie Avanzate , Naples , Italy.,f Department of Environmental, Biological and Pharmaceutical Science and Technologies , Second University of Naples , Caserta , Italy
| | - Lorenzo Chiariotti
- a Istituto di Endocrinologia ed Oncologia Sperimentale (IEOS) "Gaetano Salvatore ," Consiglio Nazionale delle Ricerche (CNR) , Naples , Italy.,b Dipartimento di Medicina Molecolare e Biotecnologie Mediche , Università degli Studi di Napoli "Federico II ," Naples , Italy.,g Dipartimento di Farmacia , Università degli Studi di Napoli "Federico II ," Naples , Italy
| | - Sergio Cocozza
- b Dipartimento di Medicina Molecolare e Biotecnologie Mediche , Università degli Studi di Napoli "Federico II ," Naples , Italy
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47
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Olariu V, Lövkvist C, Sneppen K. Nanog, Oct4 and Tet1 interplay in establishing pluripotency. Sci Rep 2016; 6:25438. [PMID: 27146218 PMCID: PMC4857071 DOI: 10.1038/srep25438] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 04/18/2016] [Indexed: 01/12/2023] Open
Abstract
A few central transcription factors inside mouse embryonic stem (ES) cells and induced pluripotent stem (iPS) cells are believed to control the cells’ pluripotency. Characterizations of pluripotent state were put forward on both transcription factor and epigenetic levels. Whereas core players have been identified, it is desirable to map out gene regulatory networks which govern the reprogramming of somatic cells as well as the early developmental decisions. Here we propose a multiple level model where the regulatory network of Oct4, Nanog and Tet1 includes positive feedback loops involving DNA-demethylation around the promoters of Oct4 and Tet1. We put forward a mechanistic understanding of the regulatory dynamics which account for i) Oct4 overexpression is sufficient to induce pluripotency in somatic cell types expressing the other Yamanaka reprogramming factors endogenously; ii) Tet1 can replace Oct4 in reprogramming cocktail; iii) Nanog is not necessary for reprogramming however its over-expression leads to enhanced self-renewal; iv) DNA methylation is the key to the regulation of pluripotency genes; v) Lif withdrawal leads to loss of pluripotency. Overall, our paper proposes a novel framework combining transcription regulation with DNA methylation modifications which, takes into account the multi-layer nature of regulatory mechanisms governing pluripotency acquisition through reprogramming.
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Affiliation(s)
- Victor Olariu
- Centre for Models of Life, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.,Computational Biology and Biological Physics, Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden
| | - Cecilia Lövkvist
- Centre for Models of Life, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Kim Sneppen
- Centre for Models of Life, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.,Centre for Models of Life, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
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48
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Lövkvist C, Dodd IB, Sneppen K, Haerter JO. DNA methylation in human epigenomes depends on local topology of CpG sites. Nucleic Acids Res 2016; 44:5123-32. [PMID: 26932361 PMCID: PMC4914085 DOI: 10.1093/nar/gkw124] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 02/20/2016] [Indexed: 01/01/2023] Open
Abstract
In vertebrates, methylation of cytosine at CpG sequences is implicated in stable and heritable patterns of gene expression. The classical model for inheritance, in which individual CpG sites are independent, provides no explanation for the observed non-random patterns of methylation. We first investigate the exact topology of CpG clustering in the human genome associated to CpG islands. Then, by pooling genomic CpG clusters on the basis of short distances between CpGs within and long distances outside clusters, we show a strong dependence of methylation on the number and density of CpG organization. CpG clusters with fewer, or less densely spaced, CpGs are predominantly hyper-methylated, while larger clusters are predominantly hypo-methylated. Intermediate clusters, however, are either hyper- or hypo-methylated but are rarely found in intermediate methylation states. We develop a model for spatially-dependent collaboration between CpGs, where methylated CpGs recruit methylation enzymes that can act on CpGs over an extended local region, while unmethylated CpGs recruit demethylation enzymes that act more strongly on nearby CpGs. This model can reproduce the effects of CpG clustering on methylation and produces stable and heritable alternative methylation states of CpG clusters, thus providing a coherent model for methylation inheritance and methylation patterning.
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Affiliation(s)
- Cecilia Lövkvist
- Center for Models of Life, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100, Copenhagen, Denmark
| | - Ian B Dodd
- Department of Molecular and Cellular Biology, University of Adelaide, SA 5005, Australia
| | - Kim Sneppen
- Center for Models of Life, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100, Copenhagen, Denmark
| | - Jan O Haerter
- Center for Models of Life, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100, Copenhagen, Denmark
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49
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Zerihun MB, Vaillant C, Jost D. Effect of replication on epigenetic memory and consequences on gene transcription. Phys Biol 2015; 12:026007. [PMID: 25884278 DOI: 10.1088/1478-3975/12/2/026007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Gene activity in eukaryotes is in part regulated at the level of chromatin through the assembly of local chromatin states that are more or less permissive to transcription. How do these chromatin states achieve their functions and whether or not they contribute to the epigenetic inheritance of the transcriptional program remain to be elucidated. In cycling cells, stability is indeed strongly challenged by the periodic occurrence of replication and cell division. To address this question, we perform simulations of the stochastic dynamics of chromatin states when driven out-of-equilibrium by periodic perturbations. We show how epigenetic memory is significantly affected by the cell cycle length. In addition, we develop a simple model to connect the epigenetic state to the transcriptional state and gene activity. In particular, it suggests that replication may induce transcriptional bursting at repressive loci. Finally, we discuss how our findings-effect of replication and link to gene transcription-have original and deep implications to various biological contexts of epigenetic memory.
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Affiliation(s)
- Mehari B Zerihun
- École Normale Supérieure de Lyon, CNRS, Laboratoire de Physique, UMR 5672, Lyon, France
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50
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Sneppen K, Dodd IB. Cooperative stabilization of the SIR complex provides robust epigenetic memory in a model of SIR silencing in Saccharomyces cerevisiae. Epigenetics 2015; 10:293-302. [PMID: 25830651 PMCID: PMC4622568 DOI: 10.1080/15592294.2015.1017200] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
How alternative chromatin-based regulatory states can be made stable and heritable in order to provide robust epigenetic memory is poorly understood. Here, we develop a stochastic model of the silencing system in Saccharomyces cerevisiae that incorporates cooperative binding of the repressive SIR complex and antisilencing histone modifications, in addition to positive feedback in Sir2 recruitment. The model was able to reproduce key features of SIR regulation of an HM locus, including heritable bistability, dependence on the silencer elements, and sensitivity to SIR dosage. We found that antisilencing methylation of H3K79 by Dot1 was not needed to generate these features, but acted to reduce spreading of SIR binding, consistent with its proposed role in containment of silencing. In contrast, cooperative inter-nucleosome interactions mediated by the SIR complex were critical for concentrating SIR binding around the silencers in the absence of barriers, and for providing bistability in SIR binding. SIR-SIR interactions magnify the cooperativity in the Sir2-histone deacetylation positive feedback reaction and complete a double-negative feedback circuit involving antisilencing modifications. Thus, our modeling underscores the potential importance of cooperative interactions between nucleosome-bound complexes both in the SIR system and in other chromatin-based complexes in epigenetic regulation.
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Affiliation(s)
- Kim Sneppen
- a Centre for Models of Life; Niels Bohr Institute; University of Copenhagen; Copenhagen , Denmark
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