1
|
Stefansson OA, Sigurpalsdottir BD, Rognvaldsson S, Halldorsson GH, Juliusson K, Sveinbjornsson G, Gunnarsson B, Beyter D, Jonsson H, Gudjonsson SA, Olafsdottir TA, Saevarsdottir S, Magnusson MK, Lund SH, Tragante V, Oddsson A, Hardarson MT, Eggertsson HP, Gudmundsson RL, Sverrisson S, Frigge ML, Zink F, Holm H, Stefansson H, Rafnar T, Jonsdottir I, Sulem P, Helgason A, Gudbjartsson DF, Halldorsson BV, Thorsteinsdottir U, Stefansson K. The correlation between CpG methylation and gene expression is driven by sequence variants. Nat Genet 2024:10.1038/s41588-024-01851-2. [PMID: 39048797 DOI: 10.1038/s41588-024-01851-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 06/27/2024] [Indexed: 07/27/2024]
Abstract
Gene promoter and enhancer sequences are bound by transcription factors and are depleted of methylated CpG sites (cytosines preceding guanines in DNA). The absence of methylated CpGs in these sequences typically correlates with increased gene expression, indicating a regulatory role for methylation. We used nanopore sequencing to determine haplotype-specific methylation rates of 15.3 million CpG units in 7,179 whole-blood genomes. We identified 189,178 methylation depleted sequences where three or more proximal CpGs were unmethylated on at least one haplotype. A total of 77,789 methylation depleted sequences (~41%) associated with 80,503 cis-acting sequence variants, which we termed allele-specific methylation quantitative trait loci (ASM-QTLs). RNA sequencing of 896 samples from the same blood draws used to perform nanopore sequencing showed that the ASM-QTL, that is, DNA sequence variability, drives most of the correlation found between gene expression and CpG methylation. ASM-QTLs were enriched 40.2-fold (95% confidence interval 32.2, 49.9) among sequence variants associating with hematological traits, demonstrating that ASM-QTLs are important functional units in the noncoding genome.
Collapse
Affiliation(s)
| | - Brynja Dogg Sigurpalsdottir
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- School of Technology, Reykjavik University, Reykjavik, Iceland
| | | | - Gisli Hreinn Halldorsson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- School of Engineering and Natural Sciences, University of Iceland, Reykjavik, Iceland
| | | | | | | | | | | | | | - Thorunn Asta Olafsdottir
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
| | - Saedis Saevarsdottir
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
| | - Magnus Karl Magnusson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
| | - Sigrun Helga Lund
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- School of Engineering and Natural Sciences, University of Iceland, Reykjavik, Iceland
| | | | | | - Marteinn Thor Hardarson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- School of Technology, Reykjavik University, Reykjavik, Iceland
| | | | | | | | | | | | - Hilma Holm
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
| | | | | | - Ingileif Jonsdottir
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
| | | | - Agnar Helgason
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Department of Anthropology, University of Iceland, Reykjavik, Iceland
| | - Daniel F Gudbjartsson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- School of Engineering and Natural Sciences, University of Iceland, Reykjavik, Iceland
| | - Bjarni V Halldorsson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- School of Technology, Reykjavik University, Reykjavik, Iceland
| | - Unnur Thorsteinsdottir
- deCODE genetics/Amgen Inc., Reykjavik, Iceland
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
| | - Kari Stefansson
- deCODE genetics/Amgen Inc., Reykjavik, Iceland.
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland.
| |
Collapse
|
2
|
Boukas L, Luperchio TR, Razi A, Hansen KD, Bjornsson HT. Neuron-specific chromatin disruption at CpG islands and aging-related regions in Kabuki syndrome mice. Genome Res 2024; 34:696-710. [PMID: 38702196 PMCID: PMC11216309 DOI: 10.1101/gr.278416.123] [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: 08/17/2023] [Accepted: 04/15/2024] [Indexed: 05/06/2024]
Abstract
Many Mendelian developmental disorders caused by coding variants in epigenetic regulators have now been discovered. Epigenetic regulators are broadly expressed, and each of these disorders typically shows phenotypic manifestations from many different organ systems. An open question is whether the chromatin disruption-the root of the pathogenesis-is similar in the different disease-relevant cell types. This is possible in principle, because all these cell types are subject to effects from the same causative gene, which has the same kind of function (e.g., methylates histones) and is disrupted by the same germline variant. We focus on mouse models for Kabuki syndrome types 1 and 2 and find that the chromatin accessibility changes in neurons are mostly distinct from changes in B or T cells. This is not because the neuronal accessibility changes occur at regulatory elements that are only active in neurons. Neurons, but not B or T cells, show preferential chromatin disruption at CpG islands and at regulatory elements linked to aging. A sensitive analysis reveals that regulatory elements disrupted in B/T cells do show chromatin accessibility changes in neurons, but these are very subtle and of uncertain functional significance. Finally, we are able to identify a small set of regulatory elements disrupted in all three cell types. Our findings reveal the cellular-context-specific effect of variants in epigenetic regulators and suggest that blood-derived episignatures, although useful diagnostically, may not be well suited for understanding the mechanistic basis of neurodevelopment in Mendelian disorders of the epigenetic machinery.
Collapse
Affiliation(s)
- Leandros Boukas
- Department of Pediatrics, Children's National Hospital, Washington, DC 20010, USA
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA
| | - Teresa Romeo Luperchio
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Afrooz Razi
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Kasper D Hansen
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA;
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21218, USA
| | - Hans T Bjornsson
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA;
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
- Faculty of Medicine, University of Iceland, 101 Reykjavík, Iceland
- Landspitali University Hospital, 101 Reykjavík, Iceland
| |
Collapse
|
3
|
Shi TH, Sugishita H, Gotoh Y. Crosstalk within and beyond the Polycomb repressive system. J Cell Biol 2024; 223:e202311021. [PMID: 38506728 PMCID: PMC10955045 DOI: 10.1083/jcb.202311021] [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: 11/06/2023] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/21/2024] Open
Abstract
The development of multicellular organisms depends on spatiotemporally controlled differentiation of numerous cell types and their maintenance. To generate such diversity based on the invariant genetic information stored in DNA, epigenetic mechanisms, which are heritable changes in gene function that do not involve alterations to the underlying DNA sequence, are required to establish and maintain unique gene expression programs. Polycomb repressive complexes represent a paradigm of epigenetic regulation of developmentally regulated genes, and the roles of these complexes as well as the epigenetic marks they deposit, namely H3K27me3 and H2AK119ub, have been extensively studied. However, an emerging theme from recent studies is that not only the autonomous functions of the Polycomb repressive system, but also crosstalks of Polycomb with other epigenetic modifications, are important for gene regulation. In this review, we summarize how these crosstalk mechanisms have improved our understanding of Polycomb biology and how such knowledge could help with the design of cancer treatments that target the dysregulated epigenome.
Collapse
Affiliation(s)
- Tianyi Hideyuki Shi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Hiroki Sugishita
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
- International Research Center for Neurointelligence, The University of Tokyo, Tokyo, Japan
| | - Yukiko Gotoh
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
- International Research Center for Neurointelligence, The University of Tokyo, Tokyo, Japan
| |
Collapse
|
4
|
Cheng Y, Song Z, Fang X, Tang Z. Polycomb repressive complex 2 and its core component EZH2: potential targeted therapeutic strategies for head and neck squamous cell carcinoma. Clin Epigenetics 2024; 16:54. [PMID: 38600608 PMCID: PMC11007890 DOI: 10.1186/s13148-024-01666-2] [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: 12/15/2023] [Accepted: 03/28/2024] [Indexed: 04/12/2024] Open
Abstract
The polycomb group (PcG) comprises a set of proteins that exert epigenetic regulatory effects and play crucial roles in diverse biological processes, ranging from pluripotency and development to carcinogenesis. Among these proteins, enhancer of zeste homolog 2 (EZH2) stands out as a catalytic component of polycomb repressive complex 2 (PRC2), which plays a role in regulating the expression of homologous (Hox) genes and initial stages of x chromosome inactivation. In numerous human cancers, including head and neck squamous cell carcinoma (HNSCC), EZH2 is frequently overexpressed or activated and has been identified as a negative prognostic factor. Notably, EZH2 emerges as a significant gene involved in regulating the STAT3/HOTAIR axis, influencing HNSCC proliferation, differentiation, and promoting metastasis by modulating related oncogenes in oral cancer. Currently, various small molecule compounds have been developed as inhibitors specifically targeting EZH2 and have gained approval for treating refractory tumors. In this review, we delve into the epigenetic regulation mediated by EZH2/PRC2 in HNSCC, with a specific focus on exploring the potential roles and mechanisms of EZH2, its crucial contribution to targeted drug therapy, and its association with cancer markers and epithelial-mesenchymal transition. Furthermore, we aim to unravel its potential as a therapeutic strategy for oral squamous cell carcinoma.
Collapse
Affiliation(s)
- Yuxi Cheng
- Xiangya Stomatological Hospital and Xiangya School of Stomatology, Central South University, Changsha, 410008, Hunan, China
- Clinical Research Center of Oral Major Diseases and Oral Health & Academician, Central South University, Changsha, 410008, Hunan, China
| | - Zhengzheng Song
- Xiangya Stomatological Hospital and Xiangya School of Stomatology, Central South University, Changsha, 410008, Hunan, China
- Clinical Research Center of Oral Major Diseases and Oral Health & Academician, Central South University, Changsha, 410008, Hunan, China
| | - Xiaodan Fang
- Xiangya Stomatological Hospital and Xiangya School of Stomatology, Central South University, Changsha, 410008, Hunan, China.
- Clinical Research Center of Oral Major Diseases and Oral Health & Academician, Central South University, Changsha, 410008, Hunan, China.
| | - Zhangui Tang
- Xiangya Stomatological Hospital and Xiangya School of Stomatology, Central South University, Changsha, 410008, Hunan, China.
- Clinical Research Center of Oral Major Diseases and Oral Health & Academician, Central South University, Changsha, 410008, Hunan, China.
| |
Collapse
|
5
|
Camellato BR, Brosh R, Ashe HJ, Maurano MT, Boeke JD. Synthetic reversed sequences reveal default genomic states. Nature 2024; 628:373-380. [PMID: 38448583 PMCID: PMC11006607 DOI: 10.1038/s41586-024-07128-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 01/29/2024] [Indexed: 03/08/2024]
Abstract
Pervasive transcriptional activity is observed across diverse species. The genomes of extant organisms have undergone billions of years of evolution, making it unclear whether these genomic activities represent effects of selection or 'noise'1-4. Characterizing default genome states could help understand whether pervasive transcriptional activity has biological meaning. Here we addressed this question by introducing a synthetic 101-kb locus into the genomes of Saccharomyces cerevisiae and Mus musculus and characterizing genomic activity. The locus was designed by reversing but not complementing human HPRT1, including its flanking regions, thus retaining basic features of the natural sequence but ablating evolved coding or regulatory information. We observed widespread activity of both reversed and native HPRT1 loci in yeast, despite the lack of evolved yeast promoters. By contrast, the reversed locus displayed no activity at all in mouse embryonic stem cells, and instead exhibited repressive chromatin signatures. The repressive signature was alleviated in a locus variant lacking CpG dinucleotides; nevertheless, this variant was also transcriptionally inactive. These results show that synthetic genomic sequences that lack coding information are active in yeast, but inactive in mouse embryonic stem cells, consistent with a major difference in 'default genomic states' between these two divergent eukaryotic cell types, with implications for understanding pervasive transcription, horizontal transfer of genetic information and the birth of new genes.
Collapse
Affiliation(s)
| | - Ran Brosh
- Institute for Systems Genetics, NYU Langone Health, New York, NY, USA
| | - Hannah J Ashe
- Institute for Systems Genetics, NYU Langone Health, New York, NY, USA
| | - Matthew T Maurano
- Institute for Systems Genetics, NYU Langone Health, New York, NY, USA
- Department of Pathology, NYU Langone Health, New York, NY, USA
| | - Jef D Boeke
- Institute for Systems Genetics, NYU Langone Health, New York, NY, USA.
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY, USA.
- Department of Biomedical Engineering, NYU Tandon School of Engineering, New York, NY, USA.
| |
Collapse
|
6
|
Boukas L, Luperchio TR, Razi A, Hansen KD, Bjornsson HT. Neuron-specific chromatin disruption at CpG islands and aging-related regions in Kabuki syndrome mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.01.551456. [PMID: 37577516 PMCID: PMC10418197 DOI: 10.1101/2023.08.01.551456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Many Mendelian developmental disorders caused by coding variants in epigenetic regulators have now been discovered. Epigenetic regulators are broadly expressed, and each of these disorders typically exhibits phenotypic manifestations from many different organ systems. An open question is whether the chromatin disruption - the root of the pathogenesis - is similar in the different disease-relevant cell types. This is possible in principle, since all these cell-types are subject to effects from the same causative gene, that has the same kind of function (e.g. methylates histones) and is disrupted by the same germline variant. We focus on mouse models for Kabuki syndrome types 1 and 2, and find that the chromatin accessibility abnormalities in neurons are mostly distinct from those in B or T cells. This is not because the neuronal abnormalities occur at regulatory elements that are only active in neurons. Neurons, but not B or T cells, show preferential chromatin disruption at CpG islands and at regulatory elements linked to aging. A sensitive analysis reveals that the regions disrupted in B/T cells do exhibit chromatin accessibility changes in neurons, but these are very subtle and of uncertain functional significance. Finally, we are able to identify a small set of regulatory elements disrupted in all three cell types. Our findings reveal the cellular-context-specific effect of variants in epigenetic regulators, and suggest that blood-derived "episignatures" may not be well-suited for understanding the mechanistic basis of neurodevelopment in Mendelian disorders of the epigenetic machinery.
Collapse
Affiliation(s)
- Leandros Boukas
- Department of Pediatrics, Children’s National Hospital
- Department of Genetic Medicine, Johns Hopkins University School of Medicine
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health
| | | | - Afrooz Razi
- Department of Genetic Medicine, Johns Hopkins University School of Medicine
| | - Kasper D. Hansen
- Department of Genetic Medicine, Johns Hopkins University School of Medicine
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health
- Department of Biomedical Engineering, Johns Hopkins School of Medicine
| | - Hans T. Bjornsson
- Department of Genetic Medicine, Johns Hopkins University School of Medicine
- Department of Pediatrics, Johns Hopkins University School of Medicine
- Faculty of Medicine, University of Iceland
- Landspitali University Hospital
| |
Collapse
|
7
|
Tompkins J, Lizhar E, Shokrani A, Wu X, Berley J, Kamali D, Hussey D, Cerneckis J, Kang TH, Wang J, Tsark W, Zeng D, Godatha S, Natarajan R, Riggs A. Engineering CpG island DNA methylation in pluripotent cells through synthetic CpG-free ssDNA insertion. CELL REPORTS METHODS 2023; 3:100465. [PMID: 37323577 PMCID: PMC10261899 DOI: 10.1016/j.crmeth.2023.100465] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 02/14/2023] [Accepted: 04/12/2023] [Indexed: 06/17/2023]
Abstract
Cellular differentiation requires global changes to DNA methylation (DNAme), where it functions to regulate transcription factor, chromatin remodeling activity, and genome interpretation. Here, we describe a simple DNAme engineering approach in pluripotent stem cells (PSCs) that stably extends DNAme across target CpG islands (CGIs). Integration of synthetic CpG-free single-stranded DNA (ssDNA) induces a target CpG island methylation response (CIMR) in multiple PSC lines, Nt2d1 embryonal carcinoma cells, and mouse PSCs but not in highly methylated CpG island hypermethylator phenotype (CIMP)+ cancer lines. MLH1 CIMR DNAme spanned the CGI, was precisely maintained through cellular differentiation, suppressed MLH1 expression, and sensitized derived cardiomyocytes and thymic epithelial cells to cisplatin. Guidelines for CIMR editing are provided, and initial CIMR DNAme is characterized at TP53 and ONECUT1 CGIs. Collectively, this resource facilitates CpG island DNAme engineering in pluripotency and the genesis of novel epigenetic models of development and disease.
Collapse
Affiliation(s)
- Joshua Tompkins
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Elizabeth Lizhar
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Alireza Shokrani
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Xiwei Wu
- Integrative Genomics Core, City of Hope, Duarte, CA 91010, USA
| | - Jordan Berley
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Diba Kamali
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Deborah Hussey
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Jonas Cerneckis
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Tae Hyuk Kang
- Integrative Genomics Core, City of Hope, Duarte, CA 91010, USA
| | - Jinhui Wang
- Integrative Genomics Core, City of Hope, Duarte, CA 91010, USA
| | - Walter Tsark
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Defu Zeng
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Swetha Godatha
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Rama Natarajan
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Arthur Riggs
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA 91010, USA
| |
Collapse
|
8
|
Regulation, functions and transmission of bivalent chromatin during mammalian development. Nat Rev Mol Cell Biol 2023; 24:6-26. [PMID: 36028557 DOI: 10.1038/s41580-022-00518-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2022] [Indexed: 12/25/2022]
Abstract
Cells differentiate and progress through development guided by a dynamic chromatin landscape that mediates gene expression programmes. During development, mammalian cells display a paradoxical chromatin state: histone modifications associated with gene activation (trimethylated histone H3 Lys4 (H3K4me3)) and with gene repression (trimethylated H3 Lys27 (H3K27me3)) co-occur at promoters of developmental genes. This bivalent chromatin modification state is thought to poise important regulatory genes for expression or repression during cell-lineage specification. In this Review, we discuss recent work that has expanded our understanding of the molecular basis of bivalent chromatin and its contributions to mammalian development. We describe the factors that establish bivalency, especially histone-lysine N-methyltransferase 2B (KMT2B) and Polycomb repressive complex 2 (PRC2), and consider evidence indicating that PRC1 shapes bivalency and may contribute to its transmission between generations. We posit that bivalency is a key feature of germline and embryonic stem cells, as well as other types of stem and progenitor cells. Finally, we discuss the relevance of bivalent chromtin to human development and cancer, and outline avenues of future research.
Collapse
|
9
|
Cabrera A, Edelstein HI, Glykofrydis F, Love KS, Palacios S, Tycko J, Zhang M, Lensch S, Shields CE, Livingston M, Weiss R, Zhao H, Haynes KA, Morsut L, Chen YY, Khalil AS, Wong WW, Collins JJ, Rosser SJ, Polizzi K, Elowitz MB, Fussenegger M, Hilton IB, Leonard JN, Bintu L, Galloway KE, Deans TL. The sound of silence: Transgene silencing in mammalian cell engineering. Cell Syst 2022; 13:950-973. [PMID: 36549273 PMCID: PMC9880859 DOI: 10.1016/j.cels.2022.11.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 09/22/2022] [Accepted: 11/22/2022] [Indexed: 12/24/2022]
Abstract
To elucidate principles operating in native biological systems and to develop novel biotechnologies, synthetic biology aims to build and integrate synthetic gene circuits within native transcriptional networks. The utility of synthetic gene circuits for cell engineering relies on the ability to control the expression of all constituent transgene components. Transgene silencing, defined as the loss of expression over time, persists as an obstacle for engineering primary cells and stem cells with transgenic cargos. In this review, we highlight the challenge that transgene silencing poses to the robust engineering of mammalian cells, outline potential molecular mechanisms of silencing, and present approaches for preventing transgene silencing. We conclude with a perspective identifying future research directions for improving the performance of synthetic gene circuits.
Collapse
Affiliation(s)
- Alan Cabrera
- Department of Bioengineering, Rice University, Houston, TX 77005, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hailey I Edelstein
- Center for Synthetic Biology, Northwestern University, Evanston, IL 60208, USA; The Eli and Edythe Broad CIRM Center, Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Fokion Glykofrydis
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033-9080, USA
| | - Kasey S Love
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sebastian Palacios
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Josh Tycko
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Meng Zhang
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Champaign, Urbana, IL 61801, USA
| | - Sarah Lensch
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Cara E Shields
- Wallace H. Coulter Department of Biomedical Engineering, Emory University, Atlanta, GA 30322, USA
| | - Mark Livingston
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - Ron Weiss
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Champaign, Urbana, IL 61801, USA
| | - Karmella A Haynes
- Wallace H. Coulter Department of Biomedical Engineering, Emory University, Atlanta, GA 30322, USA
| | - Leonardo Morsut
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033-9080, USA
| | - Yvonne Y Chen
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA; Parker Institute for Cancer Immunotherapy Center at UCLA, Los Angeles, CA 90095, USA
| | - Ahmad S Khalil
- Biological Design Center and Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Wilson W Wong
- Biological Design Center and Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - James J Collins
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033-9080, USA; Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA; Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA; Harvard-MIT Program in Health Sciences and Technology, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA
| | - Susan J Rosser
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Karen Polizzi
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, UK; Imperial College Centre for Synthetic Biology, South Kensington Campus, London, UK
| | - Michael B Elowitz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland; Faculty of Science, University of Basel, Mattenstrasse 26, Basel 4058, Switzerland
| | - Isaac B Hilton
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
| | - Joshua N Leonard
- Center for Synthetic Biology, Northwestern University, Evanston, IL 60208, USA; The Eli and Edythe Broad CIRM Center, Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Lacramioara Bintu
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Kate E Galloway
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Tara L Deans
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA.
| |
Collapse
|
10
|
Wang K, Dai R, Xia Y, Tian J, Jiao C, Mikhailova T, Zhang C, Chen C, Liu C. Spatiotemporal specificity of correlated DNA methylation and gene expression pairs across different human tissues and stages of brain development. Epigenetics 2022; 17:1110-1127. [PMID: 34652256 PMCID: PMC9543113 DOI: 10.1080/15592294.2021.1993607] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
DNA methylation (DNAm) that occurs on promoter regions is primarily considered to repress gene expression. Previous studies indicated that DNAm could also show positive correlations with gene expression. Both DNAm and gene expression profiles are known to be tissue- and development-specific. This study aims to investigate how DNAm and gene expression are coordinated across different human tissues and developmental stages, as well as the biological significance of such correlations. By analyzing 2,239 samples with both DNAm and gene expression data in the same human subjects obtained from six published datasets, we evaluated the correlations between gene and CpG pairs (GCPs) at cis-regions and compared significantly correlated GCPs (cGCPs) across different tissues and brains at different age groups. A total of 37,363 cGCPs was identified in the six datasets; approximately 38% of the cGCPs were positively correlated. The majority (>90%) of cGCPs was tissue- or development-specific. We also observed that the correlation direction can be opposite in different tissues and ages. Further analysis highlights the importance of cGCPs for their cellular functions and potential roles in complex traits and human diseases. For instance, the early developmental brain possessed a highly unique set of cGCPs that were associated with neurogenesis and psychiatric disorders. By assessing the epigenetic factors involved in cGCPs, we discovered novel regulatory mechanisms of positive cGCPs distinct from negative cGCPs, which were related to multiple factors, such as H3K27me3, CTCF, and JARD2. The catalogue of cGCPs compiled can be used to guide functional interpretation of genetic and epigenetic studies.
Collapse
Affiliation(s)
- Kangli Wang
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, and Department of Psychiatry, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Rujia Dai
- Department of Psychiatry, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Yan Xia
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, and Department of Psychiatry, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China,Department of Psychiatry, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Jianghua Tian
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, and Department of Psychiatry, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Chuan Jiao
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, and Department of Psychiatry, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China,Department of Psychiatry, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Tatiana Mikhailova
- Department of Psychiatry, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Chunling Zhang
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, Ny, USA
| | - Chao Chen
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, and Department of Psychiatry, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China,National Clinical Research Center on Mental Disorders, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Chunyu Liu
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, and Department of Psychiatry, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China,Department of Psychiatry, State University of New York Upstate Medical University, Syracuse, NY, USA,Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, Ny, USA,CONTACT Chunyu Liu Department of Psychiatry, State University of New York Upstate Medical University, Syracuse, NY13210, USA; Chao Chen Center for Medical Genetics, Central South University, Changsha, Hunan 410005, China
| |
Collapse
|
11
|
Verma A, Arya R, Brahmachari V. Identification of a polycomb responsive region in human HoxA cluster and its long-range interaction with polycomb enriched genomic regions. Gene 2022; 845:146832. [PMID: 36007803 DOI: 10.1016/j.gene.2022.146832] [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: 04/09/2022] [Revised: 08/15/2022] [Accepted: 08/18/2022] [Indexed: 11/04/2022]
Abstract
Polycomb and Trithorax group proteins (PcG, TrxG) epigenetically regulate developmental genes. These proteins bind with specific DNA elements, the Polycomb Response Element (PRE). Apart from mutations in polycomb/ trithorax proteins, altered cis-elements like PRE underlie the modified function and thus disease etiology. PREs are well studied in Drosophila, while only a few human PREs have been reported. We have identified a polycomb responsive DNA element, hPRE-HoxA3, in the intron of the HoxA3 gene. The hPRE-HoxA3 represses luciferase reporter activity in a PcG-dependent manner. The endogenous hPRE-HoxA3 element recruits PcG proteins and is enriched with repressive H3K27me3 marks, demonstrating that hPRE-HoxA3 is a part of the PcG-dependent gene regulatory network. Furthermore, it interacts with D11-12, the well-known PRE in the human Hox cluster. hPRE-Hox3 is a part of the 3-dimensional chromosomal domain organization as it is involved in the long-range interaction with other PcG enriched regions of Hox A, B, C, and D clusters.
Collapse
Affiliation(s)
- Akanksha Verma
- Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007, India.
| | - Richa Arya
- Current address- Cytogenetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
| | - Vani Brahmachari
- Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007, India
| |
Collapse
|
12
|
Comparative Transcriptomics and Methylomics Reveal Adaptive Responses of Digestive and Metabolic Genes to Dietary Shift in Giant and Red Pandas. Genes (Basel) 2022; 13:genes13081446. [PMID: 36011357 PMCID: PMC9407821 DOI: 10.3390/genes13081446] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/01/2022] [Accepted: 08/12/2022] [Indexed: 11/17/2022] Open
Abstract
Both the giant panda (Ailuropoda melanoleuca) and red panda (Ailurus fulgens) belong to the order Carnivora, but have changed their dietary habits to eating bamboo exclusively. The convergent evolution characteristics of their morphology, genome and gut flora have been found in the two pandas. However, the research on the convergent adaptation of their digestion and metabolism to the bamboo diet, mediated by the dietary shift of the two pandas at the gene-expression and epigenetic regulation levels, is still lacking. We therefore used RNA sequencing among five species (two pandas and three non-herbivore mammals) and bisulfite sequencing among three species (two pandas and a carnivore ferret) to sequence key digestion and metabolism tissues (stomach and small intestine). Our results provide evidence that the convergent differentially expressed genes (related to carbohydrate utilization, bile secretion, Lys and Arg metabolism, vitamin B12 utilization and cyanide detoxification) of the two pandas are adaptive responses to the bamboo diet containing low lipids, low Lys and Arg, low vitamin B12 and high cyanide. We also profiled the genome-wide methylome maps of giant panda, red panda and ferret, and the results indicated that the promoter methylation of the two pandas may regulate digestive and metabolic genes to adapt to sudden environmental changes, and then, transmit genetic information to future generations to evolve into bamboo eaters. Taken together, our study provides new insights into the molecular mechanisms of the dietary shift and the adaptation to a strict bamboo diet in both pandas using comparative transcriptomics and methylomics.
Collapse
|
13
|
González‐Olvera JC, Fiala R, Pless RC. Protonation of Guanine:5‐Methylcytosine and Guanine:Cytosine Base Pairs in Duplex Oligodeoxyribonucleotides. ChemistrySelect 2022. [DOI: 10.1002/slct.202200835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Julio C. González‐Olvera
- Universidad Politécnica de Santa Rosa Jáuregui Carretera Federal 57 QRO-SLP km 31-150, Parque Industrial Querétaro, Santa Rosa Jáuregui Querétaro 76220 Mexico
| | - Radovan Fiala
- CEITEC-Central European Institute of Technology Masaryk University Kamenice 753/5 62500 Brno Czech Republic
| | - Reynaldo C. Pless
- Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada Instituto Politécnico Nacional Cerro Blanco 141 Querétaro Querétaro 76090 Mexico
| |
Collapse
|
14
|
Oya S, Takahashi M, Takashima K, Kakutani T, Inagaki S. Transcription-coupled and epigenome-encoded mechanisms direct H3K4 methylation. Nat Commun 2022; 13:4521. [PMID: 35953471 PMCID: PMC9372134 DOI: 10.1038/s41467-022-32165-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 07/19/2022] [Indexed: 11/13/2022] Open
Abstract
Mono-, di-, and trimethylation of histone H3 lysine 4 (H3K4me1/2/3) are associated with transcription, yet it remains controversial whether H3K4me1/2/3 promote or result from transcription. Our previous characterizations of Arabidopsis H3K4 demethylases suggest roles for H3K4me1 in transcription. However, the control of H3K4me1 remains unexplored in Arabidopsis, in which no methyltransferase for H3K4me1 has been identified. Here, we identify three Arabidopsis methyltransferases that direct H3K4me1. Analyses of their genome-wide localization using ChIP-seq and machine learning reveal that one of the enzymes cooperates with the transcription machinery, while the other two are associated with specific histone modifications and DNA sequences. Importantly, these two types of localization patterns are also found for the other H3K4 methyltransferases in Arabidopsis and mice. These results suggest that H3K4me1/2/3 are established and maintained via interplay with transcription as well as inputs from other chromatin features, presumably enabling elaborate gene control.
Collapse
Affiliation(s)
- Satoyo Oya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
| | | | | | - Tetsuji Kakutani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
- National Institute of Genetics, Mishima, Japan.
| | - Soichi Inagaki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Japan.
| |
Collapse
|
15
|
Liu X, Liu X. PRC2, Chromatin Regulation, and Human Disease: Insights From Molecular Structure and Function. Front Oncol 2022; 12:894585. [PMID: 35800061 PMCID: PMC9255955 DOI: 10.3389/fonc.2022.894585] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/17/2022] [Indexed: 01/25/2023] Open
Abstract
Polycomb repressive complex 2 (PRC2) is a multisubunit histone-modifying enzyme complex that mediates methylation of histone H3 lysine 27 (H3K27). Trimethylated H3K27 (H3K27me3) is an epigenetic hallmark of gene silencing. PRC2 plays a crucial role in a plethora of fundamental biological processes, and PRC2 dysregulation has been repeatedly implicated in cancers and developmental disorders. Here, we review the current knowledge on mechanisms of cellular regulation of PRC2 function, particularly regarding H3K27 methylation and chromatin targeting. PRC2-related disease mechanisms are also discussed. The mode of action of PRC2 in gene regulation is summarized, which includes competition between H3K27 methylation and acetylation, crosstalk with transcription machinery, and formation of high-order chromatin structure. Recent progress in the structural biology of PRC2 is highlighted from the aspects of complex assembly, enzyme catalysis, and chromatin recruitment, which together provide valuable insights into PRC2 function in close-to-atomic detail. Future studies on the molecular function and structure of PRC2 in the context of native chromatin and in the presence of other regulators like RNAs will continue to deepen our understanding of the stability and plasticity of developmental transcriptional programs broadly impacted by PRC2.
Collapse
|
16
|
Owen BM, Davidovich C. DNA binding by polycomb-group proteins: searching for the link to CpG islands. Nucleic Acids Res 2022; 50:4813-4839. [PMID: 35489059 PMCID: PMC9122586 DOI: 10.1093/nar/gkac290] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/25/2022] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
Polycomb group proteins predominantly exist in polycomb repressive complexes (PRCs) that cooperate to maintain the repressed state of thousands of cell-type-specific genes. Targeting PRCs to the correct sites in chromatin is essential for their function. However, the mechanisms by which PRCs are recruited to their target genes in mammals are multifactorial and complex. Here we review DNA binding by polycomb group proteins. There is strong evidence that the DNA-binding subunits of PRCs and their DNA-binding activities are required for chromatin binding and CpG targeting in cells. In vitro, CpG-specific binding was observed for truncated proteins externally to the context of their PRCs. Yet, the mere DNA sequence cannot fully explain the subset of CpG islands that are targeted by PRCs in any given cell type. At this time we find very little structural and biophysical evidence to support a model where sequence-specific DNA-binding activity is required or sufficient for the targeting of CpG-dinucleotide sequences by polycomb group proteins while they are within the context of their respective PRCs, either PRC1 or PRC2. We discuss the current knowledge and open questions on how the DNA-binding activities of polycomb group proteins facilitate the targeting of PRCs to chromatin.
Collapse
Affiliation(s)
- Brady M Owen
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia
| | - Chen Davidovich
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia.,EMBL-Australia, Clayton, VIC, Australia
| |
Collapse
|
17
|
Ishihara T, Griffith OW, Suzuki S, Renfree MB. Presence of H3K4me3 on Paternally Expressed Genes of the Paternal Genome From Sperm to Implantation. Front Cell Dev Biol 2022; 10:838684. [PMID: 35359448 PMCID: PMC8960379 DOI: 10.3389/fcell.2022.838684] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 01/27/2022] [Indexed: 12/13/2022] Open
Abstract
Genomic imprinting, parent-of-origin-specific gene expression, is controlled by differential epigenetic status of the parental chromosomes. While DNA methylation and suppressive histone modifications established during gametogenesis suppress imprinted genes on the inactive allele, how and when the expressed allele gains its active status is not clear. In this study, we asked whether the active histone-3 lysine-4 trimethylation (H3K4me3) marks remain at paternally expressed genes (PEGs) in sperm and embryos before and after fertilization using published data. Here we show that mouse sperm had the active H3K4me3 at more than half of known PEGs, and these genes were present even after fertilization. Using reciprocal cross data, we identified 13 new transient PEGs during zygotic genome activation. Next, we confirmed that the 12 out of the 13 new transient PEGs were associated with the paternal H3K4me3 in sperm. Nine out of the 12 genes were associated with the paternal H3K4me3 in zygotes. Our results show that paternal H3K4me3 marks escape inactivation during the histone-to-protamine transition that occurs during sperm maturation and are present in embryos from early zygotic stages up to implantation.
Collapse
Affiliation(s)
- Teruhito Ishihara
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Oliver W. Griffith
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Shunsuke Suzuki
- Department of Agricultural and Life Sciences, Faculty of Agriculture, Shinshu University, Nagano, Japan
| | - Marilyn B. Renfree
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
- *Correspondence: Marilyn B. Renfree,
| |
Collapse
|
18
|
Cain JA, Montibus B, Oakey RJ. Intragenic CpG Islands and Their Impact on Gene Regulation. Front Cell Dev Biol 2022; 10:832348. [PMID: 35223855 PMCID: PMC8873577 DOI: 10.3389/fcell.2022.832348] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 01/20/2022] [Indexed: 11/16/2022] Open
Abstract
The mammalian genome is depleted in CG dinucleotides, except at protected regions where they cluster as CpG islands (CGIs). CGIs are gene regulatory hubs and serve as transcription initiation sites and are as expected, associated with gene promoters. Advances in genomic annotations demonstrate that a quarter of CGIs are found within genes. Such intragenic regions are repressive environments, so it is surprising that CGIs reside here and even more surprising that some resist repression and are transcriptionally active within a gene. Hence, intragenic CGI positioning within genes is not arbitrary and is instead, selected for. As a wealth of recent studies demonstrate, intragenic CGIs are embedded within genes and consequently, influence ‘host’ gene mRNA isoform length and expand transcriptome diversity.
Collapse
|
19
|
Pastor WA, Kwon SY. Distinctive aspects of the placental epigenome and theories as to how they arise. Cell Mol Life Sci 2022; 79:569. [PMID: 36287261 PMCID: PMC9606139 DOI: 10.1007/s00018-022-04568-9] [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: 03/05/2022] [Revised: 08/18/2022] [Accepted: 09/21/2022] [Indexed: 11/26/2022]
Abstract
The placenta has a methylome dramatically unlike that of any somatic cell type. Among other distinctions, it features low global DNA methylation, extensive “partially methylated domains” packed in dense heterochromatin and methylation of hundreds of CpG islands important in somatic development. These features attract interest in part because a substantial fraction of human cancers feature the exact same phenomena, suggesting parallels between epigenome formation in placentation and cancer. Placenta also features an expanded set of imprinted genes, some of which come about by distinctive developmental pathways. Recent discoveries, some from far outside the placental field, shed new light on how the unusual placental epigenetic state may arise. Nonetheless, key questions remain unresolved.
Collapse
Affiliation(s)
- William A Pastor
- Department of Biochemistry, McGill University, Montreal, QC, H3G 1Y6, Canada.
- Rosalind & Morris Goodman Cancer Institute, McGill University, Montreal, QC, H3A 1A3, Canada.
| | - Sin Young Kwon
- Department of Biochemistry, McGill University, Montreal, QC, H3G 1Y6, Canada
| |
Collapse
|
20
|
Butz S, Schmolka N, Karemaker ID, Villaseñor R, Schwarz I, Domcke S, Uijttewaal ECH, Jude J, Lienert F, Krebs AR, de Wagenaar NP, Bao X, Zuber J, Elling U, Schübeler D, Baubec T. DNA sequence and chromatin modifiers cooperate to confer epigenetic bistability at imprinting control regions. Nat Genet 2022; 54:1702-1710. [PMID: 36333500 PMCID: PMC9649441 DOI: 10.1038/s41588-022-01210-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 09/19/2022] [Indexed: 11/06/2022]
Abstract
Genomic imprinting is regulated by parental-specific DNA methylation of imprinting control regions (ICRs). Despite an identical DNA sequence, ICRs can exist in two distinct epigenetic states that are memorized throughout unlimited cell divisions and reset during germline formation. Here, we systematically study the genetic and epigenetic determinants of this epigenetic bistability. By iterative integration of ICRs and related DNA sequences to an ectopic location in the mouse genome, we first identify the DNA sequence features required for maintenance of epigenetic states in embryonic stem cells. The autonomous regulatory properties of ICRs further enabled us to create DNA-methylation-sensitive reporters and to screen for key components involved in regulating their epigenetic memory. Besides DNMT1, UHRF1 and ZFP57, we identify factors that prevent switching from methylated to unmethylated states and show that two of these candidates, ATF7IP and ZMYM2, are important for the stability of DNA and H3K9 methylation at ICRs in embryonic stem cells.
Collapse
Affiliation(s)
- Stefan Butz
- grid.7400.30000 0004 1937 0650Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland ,grid.7400.30000 0004 1937 0650Molecular Life Science PhD Program of the Life Science Zurich Graduate School, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Nina Schmolka
- grid.7400.30000 0004 1937 0650Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland ,grid.7400.30000 0004 1937 0650Present Address: Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
| | - Ino D. Karemaker
- grid.7400.30000 0004 1937 0650Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Rodrigo Villaseñor
- grid.7400.30000 0004 1937 0650Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland ,grid.5252.00000 0004 1936 973XPresent Address: Division of Molecular Biology, Biomedical Center Munich, Ludwig-Maximilians-University, Munich, Germany
| | - Isabel Schwarz
- grid.7400.30000 0004 1937 0650Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Silvia Domcke
- grid.482245.d0000 0001 2110 3787Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Faculty of Science, University of Basel, Basel, Switzerland ,grid.34477.330000000122986657Present Address: Department of Genome Sciences, University of Washington, Seattle, WA USA
| | - Esther C. H. Uijttewaal
- grid.473822.80000 0005 0375 3232Institute of Molecular Biotechnology Austria (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Julian Jude
- grid.14826.390000 0000 9799 657XResearch Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Florian Lienert
- grid.482245.d0000 0001 2110 3787Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Faculty of Science, University of Basel, Basel, Switzerland
| | - Arnaud R. Krebs
- grid.482245.d0000 0001 2110 3787Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland ,grid.4709.a0000 0004 0495 846XPresent Address: European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Heidelberg, Germany
| | - Nathalie P. de Wagenaar
- grid.5477.10000000120346234Division of Genome Biology and Epigenetics, Institute of Biodynamics and Biocomplexity, Department of Biology, Science Faculty, Utrecht University, Utrecht, the Netherlands
| | - Xue Bao
- grid.5477.10000000120346234Division of Genome Biology and Epigenetics, Institute of Biodynamics and Biocomplexity, Department of Biology, Science Faculty, Utrecht University, Utrecht, the Netherlands
| | - Johannes Zuber
- grid.14826.390000 0000 9799 657XResearch Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria ,grid.22937.3d0000 0000 9259 8492Medical University of Vienna, Vienna BioCenter (VBC), Vienna, Austria
| | - Ulrich Elling
- grid.473822.80000 0005 0375 3232Institute of Molecular Biotechnology Austria (IMBA), Vienna BioCenter (VBC), Vienna, Austria
| | - Dirk Schübeler
- grid.482245.d0000 0001 2110 3787Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Faculty of Science, University of Basel, Basel, Switzerland
| | - Tuncay Baubec
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland. .,Division of Genome Biology and Epigenetics, Institute of Biodynamics and Biocomplexity, Department of Biology, Science Faculty, Utrecht University, Utrecht, the Netherlands.
| |
Collapse
|
21
|
Sex-specific chromatin remodelling safeguards transcription in germ cells. Nature 2021; 600:737-742. [PMID: 34880491 DOI: 10.1038/s41586-021-04208-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 11/01/2021] [Indexed: 11/08/2022]
Abstract
Stability of the epigenetic landscape underpins maintenance of the cell-type-specific transcriptional profile. As one of the main repressive epigenetic systems, DNA methylation has been shown to be important for long-term gene silencing; its loss leads to ectopic and aberrant transcription in differentiated cells and cancer1. The developing mouse germ line endures global changes in DNA methylation in the absence of widespread transcriptional activation. Here, using an ultra-low-input native chromatin immunoprecipitation approach, we show that following DNA demethylation the gonadal primordial germ cells undergo remodelling of repressive histone modifications, resulting in a sex-specific signature in mice. We further demonstrate that Polycomb has a central role in transcriptional control in the newly hypomethylated germline genome as the genetic loss of Ezh2 leads to aberrant transcriptional activation, retrotransposon derepression and dramatic loss of developing female germ cells. This sex-specific effect of Ezh2 deletion is explained by the distinct landscape of repressive modifications observed in male and female germ cells. Overall, our study provides insight into the dynamic interplay between repressive chromatin modifications in the context of a developmental reprogramming system.
Collapse
|
22
|
Yaşar P, Kars G, Yavuz K, Ayaz G, Oğuztüzün Ç, Bilgen E, Suvacı Z, Çetinkol ÖP, Can T, Muyan M. A CpG island promoter drives the CXXC5 gene expression. Sci Rep 2021; 11:15655. [PMID: 34341443 PMCID: PMC8329181 DOI: 10.1038/s41598-021-95165-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/16/2021] [Indexed: 02/06/2023] Open
Abstract
CXXC5 is a member of the zinc-finger CXXC family that binds to unmethylated CpG dinucleotides. CXXC5 modulates gene expressions resulting in diverse cellular events mediated by distinct signaling pathways. However, the mechanism responsible for CXXC5 expression remains largely unknown. We found here that of the 14 annotated CXXC5 transcripts with distinct 5' untranslated regions encoding the same protein, transcript variant 2 with the highest expression level among variants represents the main transcript in cell models. The DNA segment in and at the immediate 5'-sequences of the first exon of variant 2 contains a core promoter within which multiple transcription start sites are present. Residing in a region with high G-C nucleotide content and CpG repeats, the core promoter is unmethylated, deficient in nucleosomes, and associated with active RNA polymerase-II. These findings suggest that a CpG island promoter drives CXXC5 expression. Promoter pull-down revealed the association of various transcription factors (TFs) and transcription co-regulatory proteins, as well as proteins involved in histone/chromatin, DNA, and RNA processing with the core promoter. Of the TFs, we verified that ELF1 and MAZ contribute to CXXC5 expression. Moreover, the first exon of variant 2 may contain a G-quadruplex forming region that could modulate CXXC5 expression.
Collapse
Affiliation(s)
- Pelin Yaşar
- Department of Biological Sciences, Middle East Technical University, Ankara, 06800, Turkey.
- Epigenetics and Stem Cell Biology Laboratory, Single Cell Dynamics Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC, 27709, USA.
| | - Gizem Kars
- Department of Biological Sciences, Middle East Technical University, Ankara, 06800, Turkey
| | - Kerim Yavuz
- Department of Biological Sciences, Middle East Technical University, Ankara, 06800, Turkey
| | - Gamze Ayaz
- Department of Biological Sciences, Middle East Technical University, Ankara, 06800, Turkey
- Cancer and Stem Cell Epigenetics Section, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Çerağ Oğuztüzün
- Department of Computer Engineering, Bilkent University, Ankara, 06800, Turkey
| | - Ecenaz Bilgen
- Department of Chemistry, Middle East Technical University, Ankara, 06800, Turkey
| | - Zeynep Suvacı
- Department of Chemistry, Middle East Technical University, Ankara, 06800, Turkey
| | | | - Tolga Can
- Department of Computer Engineering, Middle East Technical University, Ankara, 06800, Turkey
| | - Mesut Muyan
- Department of Biological Sciences, Middle East Technical University, Ankara, 06800, Turkey.
- Cansyl Laboratories, Middle East Technical University, Ankara, 06800, Turkey.
| |
Collapse
|
23
|
Crispatzu G, Rehimi R, Pachano T, Bleckwehl T, Cruz-Molina S, Xiao C, Mahabir E, Bazzi H, Rada-Iglesias A. The chromatin, topological and regulatory properties of pluripotency-associated poised enhancers are conserved in vivo. Nat Commun 2021; 12:4344. [PMID: 34272393 PMCID: PMC8285398 DOI: 10.1038/s41467-021-24641-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 06/21/2021] [Indexed: 12/16/2022] Open
Abstract
Poised enhancers (PEs) represent a genetically distinct set of distal regulatory elements that control the expression of major developmental genes. Before becoming activated in differentiating cells, PEs are already bookmarked in pluripotent cells with unique chromatin and topological features that could contribute to their privileged regulatory properties. However, since PEs were originally characterized in embryonic stem cells (ESC), it is currently unknown whether PEs are functionally conserved in vivo. Here, we show that the chromatin and 3D structural features of PEs are conserved among mouse pluripotent cells both in vitro and in vivo. We also uncovered that the interactions between PEs and their target genes are globally controlled by the combined action of Polycomb, Trithorax and architectural proteins. Moreover, distal regulatory sequences located close to developmental genes and displaying the typical genetic (i.e. CpG islands) and chromatin (i.e. high accessibility and H3K27me3 levels) features of PEs are commonly found across vertebrates. These putative PEs show high sequence conservation within specific vertebrate clades, with only a few being evolutionary conserved across all vertebrates. Lastly, by genetically disrupting PEs in mouse and chicken embryos, we demonstrate that these regulatory elements play essential roles during the induction of major developmental genes in vivo.
Collapse
Affiliation(s)
- Giuliano Crispatzu
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
- Department of Internal Medicine II, University Hospital Cologne, Cologne, Germany.
- Cluster of Excellence for Aging Research (CECAD), University of Cologne, Cologne, Germany.
| | - Rizwan Rehimi
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Tomas Pachano
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Tore Bleckwehl
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Sara Cruz-Molina
- Max Planck Institute for Molecular Biomedicine, Muenster, Germany
| | - Cally Xiao
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
- Cluster of Excellence for Aging Research (CECAD), University of Cologne, Cologne, Germany
- Department of Dermatology and Venereology, University Hospital Cologne, Cologne, Germany
- Laboratory of Neuro Imaging, USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
| | - Esther Mahabir
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Hisham Bazzi
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
- Cluster of Excellence for Aging Research (CECAD), University of Cologne, Cologne, Germany
- Department of Dermatology and Venereology, University Hospital Cologne, Cologne, Germany
| | - Alvaro Rada-Iglesias
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
- Cluster of Excellence for Aging Research (CECAD), University of Cologne, Cologne, Germany.
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-Universidad de Cantabria-SODERCAN, Santander, Spain.
| |
Collapse
|
24
|
Angeloni A, Bogdanovic O. Sequence determinants, function, and evolution of CpG islands. Biochem Soc Trans 2021; 49:1109-1119. [PMID: 34156435 PMCID: PMC8286816 DOI: 10.1042/bst20200695] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 12/25/2022]
Abstract
In vertebrates, cytosine-guanine (CpG) dinucleotides are predominantly methylated, with ∼80% of all CpG sites containing 5-methylcytosine (5mC), a repressive mark associated with long-term gene silencing. The exceptions to such a globally hypermethylated state are CpG-rich DNA sequences called CpG islands (CGIs), which are mostly hypomethylated relative to the bulk genome. CGIs overlap promoters from the earliest vertebrates to humans, indicating a concerted evolutionary drive compatible with CGI retention. CGIs are characterised by DNA sequence features that include DNA hypomethylation, elevated CpG and GC content and the presence of transcription factor binding sites. These sequence characteristics are congruous with the recruitment of transcription factors and chromatin modifying enzymes, and transcriptional activation in general. CGIs colocalize with sites of transcriptional initiation in hypermethylated vertebrate genomes, however, a growing body of evidence indicates that CGIs might exert their gene regulatory function in other genomic contexts. In this review, we discuss the diverse regulatory features of CGIs, their functional readout, and the evolutionary implications associated with CGI retention in vertebrates and possibly in invertebrates.
Collapse
Affiliation(s)
- Allegra Angeloni
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, Australia
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, UNSW, Sydney, Australia
| | - Ozren Bogdanovic
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, Australia
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, UNSW, Sydney, Australia
| |
Collapse
|
25
|
Li Y, Chen X, Lu C. The interplay between DNA and histone methylation: molecular mechanisms and disease implications. EMBO Rep 2021; 22:e51803. [PMID: 33844406 PMCID: PMC8097341 DOI: 10.15252/embr.202051803] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 02/16/2021] [Accepted: 03/15/2021] [Indexed: 12/21/2022] Open
Abstract
Methylation of cytosine in CpG dinucleotides and histone lysine and arginine residues is a chromatin modification that critically contributes to the regulation of genome integrity, replication, and accessibility. A strong correlation exists between the genome-wide distribution of DNA and histone methylation, suggesting an intimate relationship between these epigenetic marks. Indeed, accumulating literature reveals complex mechanisms underlying the molecular crosstalk between DNA and histone methylation. These in vitro and in vivo discoveries are further supported by the finding that genes encoding DNA- and histone-modifying enzymes are often mutated in overlapping human diseases. Here, we summarize recent advances in understanding how DNA and histone methylation cooperate to maintain the cellular epigenomic landscape. We will also discuss the potential implication of these insights for understanding the etiology of, and developing biomarkers and therapies for, human congenital disorders and cancers that are driven by chromatin abnormalities.
Collapse
Affiliation(s)
- Yinglu Li
- Department of Genetics and Development and Herbert Irving Comprehensive Cancer CenterColumbia University Irving Medical CenterNew YorkNYUSA
| | - Xiao Chen
- Department of Genetics and Development and Herbert Irving Comprehensive Cancer CenterColumbia University Irving Medical CenterNew YorkNYUSA
| | - Chao Lu
- Department of Genetics and Development and Herbert Irving Comprehensive Cancer CenterColumbia University Irving Medical CenterNew YorkNYUSA
| |
Collapse
|
26
|
Lee JY, Song J, LeBlanc L, Davis I, Kim J, Beck S. Conserved dual-mode gene regulation programs in higher eukaryotes. Nucleic Acids Res 2021; 49:2583-2597. [PMID: 33621342 PMCID: PMC7969006 DOI: 10.1093/nar/gkab108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/21/2020] [Accepted: 02/08/2021] [Indexed: 12/27/2022] Open
Abstract
Recent genomic data analyses have revealed important underlying logics in eukaryotic gene regulation, such as CpG islands (CGIs)-dependent dual-mode gene regulation. In mammals, genes lacking CGIs at their promoters are generally regulated by interconversion between euchromatin and heterochromatin, while genes associated with CGIs constitutively remain as euchromatin. Whether a similar mode of gene regulation exists in non-mammalian species has been unknown. Here, through comparative epigenomic analyses, we demonstrate that the dual-mode gene regulation program is common in various eukaryotes, even in the species lacking CGIs. In cases of vertebrates or plants, we find that genes associated with high methylation level promoters are inactivated by forming heterochromatin and expressed in a context-dependent manner. In contrast, the genes with low methylation level promoters are broadly expressed and remain as euchromatin even when repressed by Polycomb proteins. Furthermore, we show that invertebrate animals lacking DNA methylation, such as fruit flies and nematodes, also have divergence in gene types: some genes are regulated by Polycomb proteins, while others are regulated by heterochromatin formation. Altogether, our study establishes gene type divergence and the resulting dual-mode gene regulation as fundamental features shared in a broad range of higher eukaryotic species.
Collapse
Affiliation(s)
- Jun-Yeong Lee
- Davis Center for Regenerative Biology and Medicine, MDI Biological Laboratory, Bar Harbor, ME 04609, USA
| | - Jawon Song
- Texas Advanced Computing Center, The University of Texas at Austin, Austin, TX 78758, USA
| | - Lucy LeBlanc
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Ian Davis
- Davis Center for Regenerative Biology and Medicine, MDI Biological Laboratory, Bar Harbor, ME 04609, USA
| | - Jonghwan Kim
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Samuel Beck
- Davis Center for Regenerative Biology and Medicine, MDI Biological Laboratory, Bar Harbor, ME 04609, USA
| |
Collapse
|
27
|
The Role of H3K4 Trimethylation in CpG Islands Hypermethylation in Cancer. Biomolecules 2021; 11:biom11020143. [PMID: 33499170 PMCID: PMC7912453 DOI: 10.3390/biom11020143] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/30/2020] [Accepted: 01/15/2021] [Indexed: 01/01/2023] Open
Abstract
CpG methylation in transposons, exons, introns and intergenic regions is important for long-term silencing, silencing of parasitic sequences and alternative promoters, regulating imprinted gene expression and determining X chromosome inactivation. Promoter CpG islands, although rich in CpG dinucleotides, are unmethylated and remain so during all phases of mammalian embryogenesis and development, except in specific cases. The biological mechanisms that contribute to the maintenance of the unmethylated state of CpG islands remain elusive, but the modification of established DNA methylation patterns is a common feature in all types of tumors and is considered as an event that intrinsically, or in association with genetic lesions, feeds carcinogenesis. In this review, we focus on the latest results describing the role that the levels of H3K4 trimethylation may have in determining the aberrant hypermethylation of CpG islands in tumors.
Collapse
|
28
|
Xia W, Xie W. Rebooting the Epigenomes during Mammalian Early Embryogenesis. Stem Cell Reports 2020; 15:1158-1175. [PMID: 33035464 PMCID: PMC7724468 DOI: 10.1016/j.stemcr.2020.09.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 02/08/2023] Open
Abstract
Upon fertilization, terminally differentiated gametes are transformed to a totipotent zygote, which gives rise to an embryo. How parental epigenetic memories are inherited and reprogrammed to accommodate parental-to-zygotic transition remains a fundamental question in developmental biology, epigenetics, and stem cell biology. With the rapid advancement of ultra-sensitive or single-cell epigenome analysis methods, unusual principles of epigenetic reprogramming begin to be unveiled. Emerging data reveal that in many species, the parental epigenome undergoes dramatic reprogramming followed by subsequent re-establishment of the embryo epigenome, leading to epigenetic "rebooting." Here, we discuss recent progress in understanding epigenetic reprogramming and their functions during mammalian early development. We also highlight the conserved and species-specific principles underlying diverse regulation of the epigenome in early embryos during evolution.
Collapse
Affiliation(s)
- Weikun Xia
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China.
| |
Collapse
|
29
|
Liu X. A Structural Perspective on Gene Repression by Polycomb Repressive Complex 2. Subcell Biochem 2020; 96:519-562. [PMID: 33252743 DOI: 10.1007/978-3-030-58971-4_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Polycomb Repressive Complex 2 (PRC2) is a major repressive chromatin complex formed by the Polycomb Group (PcG) proteins. PRC2 mediates trimethylation of histone H3 lysine 27 (H3K27me3), a hallmark of gene silencing. PRC2 is a key regulator of development, impacting many fundamental biological processes, like stem cell differentiation in mammals and vernalization in plants. Misregulation of PRC2 function is linked to a variety of human cancers and developmental disorders. In correlation with its diverse roles in development, PRC2 displays a high degree of compositional complexity and plasticity. Structural biology research over the past decade has shed light on the molecular mechanisms of the assembly, catalysis, allosteric activation, autoinhibition, chemical inhibition, dimerization and chromatin targeting of various developmentally regulated PRC2 complexes. In addition to these aspects, structure-function analysis is also discussed in connection with disease data in this chapter.
Collapse
Affiliation(s)
- Xin Liu
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, UT Southwestern Medical Center, Dallas, TX, 75390, USA.
| |
Collapse
|
30
|
Papin C, Le Gras S, Ibrahim A, Salem H, Karimi MM, Stoll I, Ugrinova I, Schröder M, Fontaine-Pelletier E, Omran Z, Bronner C, Dimitrov S, Hamiche A. CpG Islands Shape the Epigenome Landscape. J Mol Biol 2020; 433:166659. [PMID: 33010306 DOI: 10.1016/j.jmb.2020.09.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 09/22/2020] [Accepted: 09/22/2020] [Indexed: 02/07/2023]
Abstract
Epigenetic modifications and nucleosome positioning play an important role in modulating gene expression. However, how the patterns of epigenetic modifications and nucleosome positioning are established around promoters is not well understood. Here, we have addressed these questions in a series of genome-wide experiments coupled to a novel bioinformatic analysis approach. Our data reveal a clear correlation between CpG density, promoter activity and accumulation of active or repressive histone marks. CGI boundaries define the chromatin promoter regions that will be epigenetically modified. CpG-rich promoters are targeted by histone modifications and histone variants, while CpG-poor promoters are regulated by DNA methylation. CGIs boundaries, but not transcriptional activity, are essential determinants of H2A.Z positioning in vicinity of the promoters, suggesting that the presence of H2A.Z is not related to transcriptional control. Accordingly, H2A.Z depletion has no impact on gene expression of arrested mouse embryonic fibroblasts. Therefore, the underlying DNA sequence, the promoter CpG density and, to a lesser extent, transcriptional activity, are key factors implicated in promoter chromatin architecture.
Collapse
Affiliation(s)
- Christophe Papin
- Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), UdS, CNRS, INSERM, Equipe labellisée Ligue contre le Cancer, 1 rue Laurent Fries, B.P. 10142,67404 Illkirch Cedex, France.
| | - Stéphanie Le Gras
- Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), UdS, CNRS, INSERM, Equipe labellisée Ligue contre le Cancer, 1 rue Laurent Fries, B.P. 10142,67404 Illkirch Cedex, France
| | - Abdulkhaleg Ibrahim
- Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), UdS, CNRS, INSERM, Equipe labellisée Ligue contre le Cancer, 1 rue Laurent Fries, B.P. 10142,67404 Illkirch Cedex, France; Biotechnology Research Center (BTRC), Tripoli, Libya
| | - Hatem Salem
- Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), UdS, CNRS, INSERM, Equipe labellisée Ligue contre le Cancer, 1 rue Laurent Fries, B.P. 10142,67404 Illkirch Cedex, France; Biotechnology Research Center (BTRC), Tripoli, Libya
| | - Mohammad Mahdi Karimi
- Comprehensive Cancer Centre, School of Cancer & Pharmaceutical Sciences, Faculty of Life Sciences & Medicine, King's College London, Denmark Hill, London, UK
| | - Isabelle Stoll
- Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), UdS, CNRS, INSERM, Equipe labellisée Ligue contre le Cancer, 1 rue Laurent Fries, B.P. 10142,67404 Illkirch Cedex, France
| | - Iva Ugrinova
- Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Maria Schröder
- Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Emeline Fontaine-Pelletier
- Institute for Advanced Biosciences, Inserm U 1209, CNRS UMR 5309, Université Grenoble Alpes, 38000 Grenoble, France
| | - Ziad Omran
- Umm AlQura University, Faculty of Pharmacy, Saudi Arabia
| | - Christian Bronner
- Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), UdS, CNRS, INSERM, Equipe labellisée Ligue contre le Cancer, 1 rue Laurent Fries, B.P. 10142,67404 Illkirch Cedex, France
| | - Stefan Dimitrov
- Roumen Tsanev Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria; Institute for Advanced Biosciences, Inserm U 1209, CNRS UMR 5309, Université Grenoble Alpes, 38000 Grenoble, France.
| | - Ali Hamiche
- Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), UdS, CNRS, INSERM, Equipe labellisée Ligue contre le Cancer, 1 rue Laurent Fries, B.P. 10142,67404 Illkirch Cedex, France.
| |
Collapse
|
31
|
Boukas L, Bjornsson HT, Hansen KD. Promoter CpG Density Predicts Downstream Gene Loss-of-Function Intolerance. Am J Hum Genet 2020; 107:487-498. [PMID: 32800095 PMCID: PMC7477270 DOI: 10.1016/j.ajhg.2020.07.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 07/22/2020] [Indexed: 12/26/2022] Open
Abstract
The aggregation and joint analysis of large numbers of exome sequences has recently made it possible to derive estimates of intolerance to loss-of-function (LoF) variation for human genes. Here, we demonstrate strong and widespread coupling between genic LoF intolerance and promoter CpG density across the human genome. Genes downstream of the most CpG-rich promoters (top 10% CpG density) have a 67.2% probability of being highly LoF intolerant, using the LOEUF metric from gnomAD. This is in contrast to 7.4% of genes downstream of the most CpG-poor (bottom 10% CpG density) promoters. Combining promoter CpG density with exonic and promoter conservation explains 33.4% of the variation in LOEUF, and the contribution of CpG density exceeds the individual contributions of exonic and promoter conservation. We leverage this to train a simple and easily interpretable predictive model that outperforms other existing predictors and allows us to classify 1,760 genes-which are currently unascertained in gnomAD-as highly LoF intolerant or not. These predictions have the potential to aid in the interpretation of novel variants in the clinical setting. Moreover, our results reveal that high CpG density is not merely a generic feature of human promoters but is preferentially encountered at the promoters of the most selectively constrained genes, calling into question the prevailing view that CpG islands are not subject to selection.
Collapse
Affiliation(s)
- Leandros Boukas
- Human Genetics Training Program, Johns Hopkins University School of Medicine, 733 N Broadway, Baltimore, MD 21205, USA; Department of Genetic Medicine, Johns Hopkins University School of Medicine, 733 N Broadway, Baltimore, MD 21205, USA
| | - Hans T Bjornsson
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, 733 N Broadway, Baltimore, MD 21205, USA; Department of Pediatrics, Johns Hopkins University School of Medicine, 1800 Orleans Street, Baltimore, MD 21287, USA; Faculty of Medicine, University of Iceland, Sturlugata 8, 101 Reykjavik, Iceland; Landspitali University Hospital, Hringbraut, 101 Reykjavik, Iceland.
| | - Kasper D Hansen
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, 733 N Broadway, Baltimore, MD 21205, USA; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA.
| |
Collapse
|
32
|
Mao SQ, Cuesta SM, Tannahill D, Balasubramanian S. Genome-wide DNA Methylation Signatures Are Determined by DNMT3A/B Sequence Preferences. Biochemistry 2020; 59:2541-2550. [PMID: 32543182 PMCID: PMC7364778 DOI: 10.1021/acs.biochem.0c00339] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/16/2020] [Indexed: 12/24/2022]
Abstract
Cytosine methylation is an important epigenetic mark, but how the distinctive patterns of DNA methylation arise remains elusive. For the first time, we systematically investigated how these patterns can be imparted by the inherent enzymatic preferences of mammalian de novo DNA methyltransferases in vitro and the extent to which this applies in cells. In a biochemical experiment, we subjected a wide variety of DNA sequences to methylation by DNMT3A or DNMT3B and then applied deep bisulfite sequencing to quantitatively determine the sequence preferences for methylation. The data show that DNMT3A prefers CpG and non-CpG sites followed by a 3'-pyrimidine, whereas DNMT3B favors a 3'-purine. Overall, we show that DNMT3A has a sequence preference for a TNC[G/A]CC context, while DNMT3B prefers TAC[G/A]GC. We extended our finding using publicly available data from mouse Dnmt1/3a/3b triple-knockout cells in which reintroduction of either DNMT3A or DNMT3B expression results in the acquisition of the same enzyme specific signature sequences observed in vitro. Furthermore, loss of DNMT3A or DNMT3B in human embryonic stem cells leads to a loss of methylation at the corresponding enzyme specific signatures. Therefore, the global DNA methylation landscape of the mammalian genome can be fundamentally determined by the inherent sequence preference of de novo methyltransferases.
Collapse
Affiliation(s)
- Shi-Qing Mao
- Cancer
Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge CB2 0RE, U.K.
| | - Sergio Martínez Cuesta
- Cancer
Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge CB2 0RE, U.K.
- Department
of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - David Tannahill
- Cancer
Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge CB2 0RE, U.K.
| | - Shankar Balasubramanian
- Cancer
Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge CB2 0RE, U.K.
- Department
of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
- School
of Clinical Medicine, University of Cambridge, Cambridge CB2 0SP, U.K.
| |
Collapse
|
33
|
Abstract
Predicting regulatory potential from primary DNA sequences or transcription factor binding patterns is not possible. However, the annotation of the genome by chromatin proteins, histone modifications, and differential compaction is largely sufficient to reveal the locations of genes and their differential activity states. The Polycomb Group (PcG) and Trithorax Group (TrxG) proteins are the central players in this cell type-specific chromatin organization. PcG function was originally viewed as being solely repressive and irreversible, as observed at the homeotic loci in flies and mammals. However, it is now clear that modular and reversible PcG function is essential at most developmental genes. Focusing mainly on recent advances, we review evidence for how PcG and TrxG patterns change dynamically during cell type transitions. The ability to implement cell type-specific transcriptional programming with exquisite fidelity is essential for normal development.
Collapse
Affiliation(s)
- Mitzi I Kuroda
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA; ,
| | - Hyuckjoon Kang
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA; ,
| | - Sandip De
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA; ,
| | - Judith A Kassis
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA; ,
| |
Collapse
|
34
|
Pirogov A, Pfaffelhuber P, Börsch-Haubold A, Haubold B. High-complexity regions in mammalian genomes are enriched for developmental genes. Bioinformatics 2020; 35:1813-1819. [PMID: 30395202 PMCID: PMC6546125 DOI: 10.1093/bioinformatics/bty922] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/17/2018] [Accepted: 11/02/2018] [Indexed: 12/01/2022] Open
Abstract
Motivation Unique sequence regions are associated with genetic function in vertebrate genomes. However, measuring uniqueness, or absence of long repeats, along a genome is conceptually and computationally difficult. Here we use a variant of the Lempel-Ziv complexity, the match complexity, Cm, and augment it by deriving its null distribution for random sequences. We then apply Cm to the human and mouse genomes to investigate the relationship between sequence complexity and function. Results We implemented Cm in the program macle and show through simulation that the newly derived null distribution of Cm is accurate. This allows us to delineate high-complexity regions in the human and mouse genomes. Using our program macle2go, we find that these regions are twofold enriched for genes. Moreover, the genes contained in these regions are more than 10-fold enriched for developmental functions. Availability and implementation Source code for macle and macle2go is available from www.github.com/evolbioinf/macle and www.github.com/evolbioinf/macle2go, respectively; Cm browser tracks from guanine.evolbio.mgp.de/complexity. Supplementary information Supplementary data are available at Bioinformatics online.
Collapse
Affiliation(s)
- Anton Pirogov
- Lehrstuhl für Informatik, RWTH Aachen University, Max-Planck-Institute for Evolutionary Biology, Plön, Germany.,Department of Evolutionary Genetics, Max-Planck-Institute for Evolutionary Biology, Plön, Germany
| | | | | | - Bernhard Haubold
- Department of Evolutionary Genetics, Max-Planck-Institute for Evolutionary Biology, Plön, Germany
| |
Collapse
|
35
|
Enhancer DNA methylation: implications for gene regulation. Essays Biochem 2020; 63:707-715. [PMID: 31551326 DOI: 10.1042/ebc20190030] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 09/08/2019] [Accepted: 09/10/2019] [Indexed: 12/13/2022]
Abstract
DNA methylation involves the addition of a methyl group to the fifth carbon of the pyrimidine cytosine ring (5-methylcytosine, 5mC). 5mC is widespread in vertebrate genomes where it is predominantly found within CpG dinucleotides. In mammals, 5mC participates in long-term silencing processes such as X-chromosome inactivation, genomic imprinting, somatic silencing of germline genes, and silencing of repetitive DNA elements. The evidence for 5mC as a dynamic gene-regulatory mechanism is mostly limited to specific examples, and is far from being completely understood. Recent work from diverse model systems suggests that 5mC might not always act as a dominant repressive mechanism and that hypermethylated promoters and enhancers can be permissive to transcription in vivo and in vitro. In this review, we discuss the links between 5mC and enhancer activity, and evaluate the role of this biochemical mechanism in various biological contexts.
Collapse
|
36
|
Singh R, Sophiarani Y. A report on DNA sequence determinants in gene expression. Bioinformation 2020; 16:422-431. [PMID: 32831525 PMCID: PMC7434957 DOI: 10.6026/97320630016422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 11/26/2022] Open
Abstract
The biased usage of nucleotides in coding sequence and its correlation with gene expression has been observed in several studies. A complex set of interactions between genes and other components of the expression system determine the amount of proteins produced from coding sequences. It is known that the elongation rate of polypeptide chain is affected by both codon usage bias and specific amino acid compositional constraints. Therefore, it is of interest to review local DNA-sequence elements and other positional as well as combinatorial constraints that play significant role in gene expression.
Collapse
Affiliation(s)
- Ravail Singh
- Indian Institute of Integrative Medicine, CSIR, Canal Road, Jammu-180001
| | | |
Collapse
|
37
|
Identification of a PRC2 Accessory Subunit Required for Subtelomeric H3K27 Methylation in Neurospora crassa. Mol Cell Biol 2020; 40:MCB.00003-20. [PMID: 32179551 DOI: 10.1128/mcb.00003-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 03/11/2020] [Indexed: 02/07/2023] Open
Abstract
Polycomb repressive complex 2 (PRC2) catalyzes methylation of histone H3 at lysine 27 (H3K27) in genomic regions of most eukaryotes and is critical for maintenance of the associated transcriptional repression. However, the mechanisms that shape the distribution of H3K27 methylation, such as recruitment of PRC2 to chromatin and/or stimulation of PRC2 activity, are unclear. Here, using a forward genetic approach in the model organism Neurospora crassa, we identified two alleles of a gene, NCU04278, encoding an unknown PRC2 accessory subunit (PAS). Loss of PAS resulted in losses of H3K27 methylation concentrated near the chromosome ends and derepression of a subset of associated subtelomeric genes. Immunoprecipitation followed by mass spectrometry confirmed reciprocal interactions between PAS and known PRC2 subunits, and sequence similarity searches demonstrated that PAS is not unique to N. crassa PAS homologs likely influence the distribution of H3K27 methylation and underlying gene repression in a variety of fungal lineages.
Collapse
|
38
|
Understanding the interplay between CpG island-associated gene promoters and H3K4 methylation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194567. [PMID: 32360393 PMCID: PMC7294231 DOI: 10.1016/j.bbagrm.2020.194567] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/24/2020] [Accepted: 04/22/2020] [Indexed: 02/07/2023]
Abstract
The precise regulation of gene transcription is required to establish and maintain cell type-specific gene expression programs during multicellular development. In addition to transcription factors, chromatin, and its chemical modification, play a central role in regulating gene expression. In vertebrates, DNA is pervasively methylated at CG dinucleotides, a modification that is repressive to transcription. However, approximately 70% of vertebrate gene promoters are associated with DNA elements called CpG islands (CGIs) that are refractory to DNA methylation. CGIs integrate the activity of a range of chromatin-regulating factors that can post-translationally modify histones and modulate gene expression. This is exemplified by the trimethylation of histone H3 at lysine 4 (H3K4me3), which is enriched at CGI-associated gene promoters and correlates with transcriptional activity. Through studying H3K4me3 at CGIs it has become clear that CGIs shape the distribution of H3K4me3 and, in turn, H3K4me3 influences the chromatin landscape at CGIs. Here we will discuss our understanding of the emerging relationship between CGIs, H3K4me3, and gene expression.
Collapse
|
39
|
Oudinet C, Braikia FZ, Dauba A, Khamlichi AA. Recombination may occur in the absence of transcription in the immunoglobulin heavy chain recombination centre. Nucleic Acids Res 2020; 48:3553-3566. [PMID: 32086526 PMCID: PMC7144927 DOI: 10.1093/nar/gkaa108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 02/06/2020] [Accepted: 02/19/2020] [Indexed: 12/18/2022] Open
Abstract
Developing B cells undergo V(D)J recombination to generate a vast repertoire of Ig molecules. V(D)J recombination is initiated by the RAG1/RAG2 complex in recombination centres (RCs), where gene segments become accessible to the complex. Whether transcription is the causal factor of accessibility or whether it is a side product of other processes that generate accessibility remains a controversial issue. At the IgH locus, V(D)J recombination is controlled by Eμ enhancer, which directs the transcriptional, epigenetic and recombinational events in the IgH RC. Deletion of Eμ enhancer affects both transcription and recombination, making it difficult to conclude if Eμ controls the two processes through the same or different mechanisms. By using a mouse line carrying a CpG-rich sequence upstream of Eμ enhancer and analyzing transcription and recombination at the single-cell level, we found that recombination could occur in the RC in the absence of detectable transcription, suggesting that Eμ controls transcription and recombination through distinct mechanisms. Moreover, while the normally Eμ-dependent transcription and demethylating activities were impaired, recruitment of chromatin remodeling complexes was unaffected. RAG1 was efficiently recruited, thus compensating for the defective transcription-associated recruitment of RAG2, and providing a mechanistic basis for RAG1/RAG2 assembly to initiate V(D)J recombination.
Collapse
Affiliation(s)
- Chloé Oudinet
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, 31077 Toulouse, France
| | - Fatima-Zohra Braikia
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, 31077 Toulouse, France
| | - Audrey Dauba
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, 31077 Toulouse, France
| | - Ahmed Amine Khamlichi
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, 31077 Toulouse, France
| |
Collapse
|
40
|
Criqui M, Qamra A, Chu TW, Sharma M, Tsao J, Henry DA, Barsyte-Lovejoy D, Arrowsmith CH, Winegarden N, Lupien M, Harrington L. Telomere dysfunction cooperates with epigenetic alterations to impair murine embryonic stem cell fate commitment. eLife 2020; 9:47333. [PMID: 32297856 PMCID: PMC7192583 DOI: 10.7554/elife.47333] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 04/06/2020] [Indexed: 12/11/2022] Open
Abstract
The precise relationship between epigenetic alterations and telomere dysfunction is still an extant question. Previously, we showed that eroded telomeres lead to differentiation instability in murine embryonic stem cells (mESCs) via DNA hypomethylation at pluripotency-factor promoters. Here, we uncovered that telomerase reverse transcriptase null (Tert-/-) mESCs exhibit genome-wide alterations in chromatin accessibility and gene expression during differentiation. These changes were accompanied by an increase of H3K27me3 globally, an altered chromatin landscape at the Pou5f1/Oct4 promoter, and a refractory response to differentiation cues. Inhibition of the Polycomb Repressive Complex 2 (PRC2), an H3K27 tri-methyltransferase, exacerbated the impairment in differentiation and pluripotency gene repression in Tert-/-mESCs but not wild-type mESCs, whereas inhibition of H3K27me3 demethylation led to a partial rescue of the Tert-/- phenotype. These data reveal a new interdependent relationship between H3K27me3 and telomere integrity in stem cell lineage commitment that may have implications in aging and cancer.
Collapse
Affiliation(s)
- Mélanie Criqui
- Institut de Recherche en Immunologie et Cancérologie (IRIC), Département de biologie moléculaire, Faculté de Médecine, Université de Montréal, Montréal, Canada
| | - Aditi Qamra
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Tsz Wai Chu
- Institut de Recherche en Immunologie et Cancérologie (IRIC), Département de biologie moléculaire, Faculté de Médecine, Université de Montréal, Montréal, Canada
| | - Monika Sharma
- Princess Margaret Genomics Centre, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Julissa Tsao
- Princess Margaret Genomics Centre, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Danielle A Henry
- Institut de Recherche en Immunologie et Cancérologie (IRIC), Département de biologie moléculaire, Faculté de Médecine, Université de Montréal, Montréal, Canada
| | - Dalia Barsyte-Lovejoy
- Structural Genomics Consortium, Princess Margaret Cancer Centre, University of Toronto, Department of Medical Biophysics, Toronto, Canada
| | - Cheryl H Arrowsmith
- Structural Genomics Consortium, Princess Margaret Cancer Centre, University of Toronto, Department of Medical Biophysics, Toronto, Canada
| | - Neil Winegarden
- Princess Margaret Genomics Centre, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Mathieu Lupien
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - Lea Harrington
- Institut de Recherche en Immunologie et Cancérologie (IRIC), Département de biologie moléculaire, Faculté de Médecine, Université de Montréal, Montréal, Canada
| |
Collapse
|
41
|
Chen S, Jiao L, Liu X, Yang X, Liu X. A Dimeric Structural Scaffold for PRC2-PCL Targeting to CpG Island Chromatin. Mol Cell 2020; 77:1265-1278.e7. [PMID: 31959557 PMCID: PMC7571800 DOI: 10.1016/j.molcel.2019.12.019] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 09/30/2019] [Accepted: 12/23/2019] [Indexed: 01/15/2023]
Abstract
Diverse accessory subunits are involved in the recruitment of polycomb repressive complex 2 (PRC2) to CpG island (CGI) chromatin. Here we report the crystal structure of a SUZ12-RBBP4 complex bound to fragments of the accessory subunits PHF19 and JARID2. Unexpectedly, this complex adopts a dimeric structural architecture, accounting for PRC2 self-association that has long been implicated. The intrinsic PRC2 dimer is formed via domain swapping involving RBBP4 and the unique C2 domain of SUZ12. MTF2 and PHF19 associate with PRC2 at around the dimer interface and stabilize the dimer. Conversely, AEBP2 binding results in a drastic movement of the C2 domain, disrupting the intrinsic PRC2 dimer. PRC2 dimerization enhances CGI DNA binding by PCLs in pairs in vitro, reminiscent of the widespread phenomenon of transcription factor dimerization in active transcription. Loss of PRC2 dimerization impairs histone H3K27 trimethylation (H3K27me3) on chromatin at developmental gene loci in mouse embryonic stem cells.
Collapse
Affiliation(s)
- Siming Chen
- Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Research, Department of Obstetrics and Gynecology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biophysics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Lianying Jiao
- Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Research, Department of Obstetrics and Gynecology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biophysics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xiuli Liu
- Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Research, Department of Obstetrics and Gynecology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biophysics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xin Yang
- Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Research, Department of Obstetrics and Gynecology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biophysics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xin Liu
- Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Research, Department of Obstetrics and Gynecology, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biophysics, UT Southwestern Medical Center, Dallas, TX 75390, USA.
| |
Collapse
|
42
|
Jara-Espejo M, Line SR. DNA G-quadruplex stability, position and chromatin accessibility are associated with CpG island methylation. FEBS J 2019; 287:483-495. [PMID: 31532882 DOI: 10.1111/febs.15065] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/22/2019] [Accepted: 09/16/2019] [Indexed: 01/06/2023]
Abstract
CpG islands (CGI) are genomic regions associated with gene promoters and involved in gene expression regulation. Despite their high CpG content and unlike bulk genomic DNA methylation pattern, these regions are usually hypomethylated. So far, the mechanisms controlling the CGI methylation patterning remain unclear. G-quadruplex (G4) structures can inhibit DNA methyltransferases 1 enzymatic activity, leading to CGI hypomethylation. Our aim was to analyse the association of G4 forming sequences (G4FS) and CGI methylation as well as to determine the intrinsic and extrinsic characteristics of G4FS that may modulate this phenomenon. Using methylation data from human embryonic stem cells (hESCs) and three hESC-derived populations, we showed that hypomethylated CpGs located inside CGI (CGI/CpG) tend to be associated with highly stable G4FS (Minimum free energy ≤ -30 kcal·mol-1 ). The association of highly stable G4FS and hypomethylation tend to be stronger when these structures are located at shorter distances (~ < 150 bp) from GCI/CpGs, when G4FS and CpGs are located within open chromatin and G4FS are inside CGI. Moreover, this association is not strongly influenced by the CpG content of CGI. Conversely, highly methylated CGI/CpG tend to be associated with low stability G4FS. Although CpGs inside CGIs without a G4FS tend to be more methylated, high stability G4FS within CGI neighbourhood were associated with decreased methylation. In summary, our data indicate that G4FS may act as protective cis elements against CGI methylation, and this effect seems to be influenced by the G4FS folding potential, its presence within CGI, CpG distance from G4FS and chromatin accessibility.
Collapse
Affiliation(s)
- Manuel Jara-Espejo
- Department of Morphology, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, Brazil
| | - Sérgio Roberto Line
- Department of Morphology, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, Brazil
| |
Collapse
|
43
|
Højfeldt JW, Hedehus L, Laugesen A, Tatar T, Wiehle L, Helin K. Non-core Subunits of the PRC2 Complex Are Collectively Required for Its Target-Site Specificity. Mol Cell 2019; 76:423-436.e3. [PMID: 31521506 DOI: 10.1016/j.molcel.2019.07.031] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/13/2019] [Accepted: 07/19/2019] [Indexed: 12/31/2022]
Abstract
The Polycomb repressive complex 2 (PRC2) catalyzes H3K27 methylation across the genome, which impacts transcriptional regulation and is critical for establishment of cell identity. Because of its essential function during development and in cancer, understanding the delineation of genome-wide H3K27 methylation patterns has been the focus of intense investigation. PRC2 methylation activity is abundant and dispersed throughout the genome, but the highest activity is specifically directed to a subset of target sites that are stably occupied by the complex and highly enriched for H3K27me3. Here, we show, by systematically knocking out single and multiple non-core subunits of the PRC2 complex in mouse embryonic stem cells, that they each contribute to directing PRC2 activity to target sites. Furthermore, combined knockout of six non-core subunits reveals that, while dispensable for global H3K27 methylation levels, the non-core PRC2 subunits are collectively required for focusing H3K27me3 activity to specific sites in the genome.
Collapse
Affiliation(s)
- Jonas Westergaard Højfeldt
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen N 2200, Denmark; The Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, Copenhagen N 2200, Denmark
| | - Lin Hedehus
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen N 2200, Denmark; The Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, Copenhagen N 2200, Denmark
| | - Anne Laugesen
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen N 2200, Denmark; The Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, Copenhagen N 2200, Denmark
| | - Tülin Tatar
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen N 2200, Denmark; The Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, Copenhagen N 2200, Denmark
| | - Laura Wiehle
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen N 2200, Denmark; The Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, Copenhagen N 2200, Denmark
| | - Kristian Helin
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen N 2200, Denmark; The Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, Copenhagen N 2200, Denmark; Cell Biology Program and Center for Epigenetics Research, Memorial Sloan Kettering Cancer Center (MSKCC), New York, NY 10065, USA.
| |
Collapse
|
44
|
SETD2 regulates the maternal epigenome, genomic imprinting and embryonic development. Nat Genet 2019; 51:844-856. [DOI: 10.1038/s41588-019-0398-7] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 03/18/2019] [Indexed: 11/09/2022]
|
45
|
Laugesen A, Højfeldt JW, Helin K. Molecular Mechanisms Directing PRC2 Recruitment and H3K27 Methylation. Mol Cell 2019; 74:8-18. [PMID: 30951652 PMCID: PMC6452890 DOI: 10.1016/j.molcel.2019.03.011] [Citation(s) in RCA: 339] [Impact Index Per Article: 67.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 02/12/2019] [Accepted: 03/05/2019] [Indexed: 02/07/2023]
Abstract
The polycomb repressive complex 2 (PRC2) is a chromatin-associated methyltransferase catalyzing mono-, di-, and trimethylation of lysine 27 on histone H3 (H3K27). This activity is required for normal organismal development and maintenance of gene expression patterns to uphold cell identity. PRC2 function is often deregulated in disease and is a promising candidate for therapeutic targeting in cancer. In this review, we discuss the molecular mechanisms proposed to take part in modulating PRC2 recruitment and shaping H3K27 methylation patterns across the genome. This includes consideration of factors influencing PRC2 residence time on chromatin and PRC2 catalytic activity with a focus on the mechanisms giving rise to regional preferences and differential deposition of H3K27 methylation. We further discuss existing evidence for functional diversity between distinct subsets of PRC2 complexes with the aim of extracting key concepts and highlighting major open questions toward a more complete understanding of PRC2 function.
Collapse
Affiliation(s)
- Anne Laugesen
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark; The Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Jonas Westergaard Højfeldt
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark; The Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
| | - Kristian Helin
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark; The Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark; Cell Biology Program and Center for Epigenetics Research, Memorial Sloan Kettering Cancer Center (MSKCC), 1275 York Avenue, New York, NY 10065, USA.
| |
Collapse
|
46
|
Illingworth RS. Chromatin folding and nuclear architecture: PRC1 function in 3D. Curr Opin Genet Dev 2019; 55:82-90. [PMID: 31323466 PMCID: PMC6859790 DOI: 10.1016/j.gde.2019.06.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 12/20/2022]
Abstract
Embryonic development requires the intricate balance between the expansion and specialisation of defined cell types in time and space. The gene expression programmes that underpin this balance are regulated, in part, by modulating the chemical and structural state of chromatin. Polycomb repressive complexes (PRCs), a family of essential developmental regulators, operate at this level to stabilise or perpetuate a repressed but transcriptionally poised chromatin configuration. This dynamic state is required to control the timely initiation of productive gene transcription during embryonic development. The two major PRCs cooperate to target the genome, but it is PRC1 that appears to be the primary effector that controls gene expression. In this review I will discuss recent findings relating to how PRC1 alters chromatin accessibility, folding and global 3D nuclear organisation to control gene transcription.
Collapse
Affiliation(s)
- Robert S Illingworth
- MRC Centre for Regenerative Medicine, Institute for Regeneration and Repair, The University of Edinburgh, Edinburgh BioQuarter, 5 Little France Drive, Edinburgh, EH16 4UU, United Kingdom.
| |
Collapse
|
47
|
Hartl D, Krebs AR, Grand RS, Baubec T, Isbel L, Wirbelauer C, Burger L, Schübeler D. CG dinucleotides enhance promoter activity independent of DNA methylation. Genome Res 2019; 29:554-563. [PMID: 30709850 PMCID: PMC6442381 DOI: 10.1101/gr.241653.118] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 01/24/2019] [Indexed: 11/24/2022]
Abstract
Most mammalian RNA polymerase II initiation events occur at CpG islands, which are rich in CpGs and devoid of DNA methylation. Despite their relevance for gene regulation, it is unknown to what extent the CpG dinucleotide itself actually contributes to promoter activity. To address this question, we determined the transcriptional activity of a large number of chromosomally integrated promoter constructs and monitored binding of transcription factors assumed to play a role in CpG island activity. This revealed that CpG density significantly improves motif-based prediction of transcription factor binding. Our experiments also show that high CpG density alone is insufficient for transcriptional activity, yet results in increased transcriptional output when combined with particular transcription factor motifs. However, this CpG contribution to promoter activity is independent of DNA methyltransferase activity. Together, this refines our understanding of mammalian promoter regulation as it shows that high CpG density within CpG islands directly contributes to an environment permissive for full transcriptional activity.
Collapse
Affiliation(s)
- Dominik Hartl
- Friedrich Miescher Institute for Biomedical Research, CH 4058 Basel, Switzerland.,Faculty of Sciences, University of Basel, CH 4003 Basel, Switzerland
| | - Arnaud R Krebs
- Friedrich Miescher Institute for Biomedical Research, CH 4058 Basel, Switzerland
| | - Ralph S Grand
- Friedrich Miescher Institute for Biomedical Research, CH 4058 Basel, Switzerland
| | - Tuncay Baubec
- Friedrich Miescher Institute for Biomedical Research, CH 4058 Basel, Switzerland
| | - Luke Isbel
- Friedrich Miescher Institute for Biomedical Research, CH 4058 Basel, Switzerland
| | | | - Lukas Burger
- Friedrich Miescher Institute for Biomedical Research, CH 4058 Basel, Switzerland.,Swiss Institute of Bioinformatics, CH 4058 Basel, Switzerland
| | - Dirk Schübeler
- Friedrich Miescher Institute for Biomedical Research, CH 4058 Basel, Switzerland.,Faculty of Sciences, University of Basel, CH 4003 Basel, Switzerland
| |
Collapse
|
48
|
Jiao Y, Feng Y, Wang X. Regulation of Tumor Suppressor Gene CDKN2A and Encoded p16-INK4a Protein by Covalent Modifications. BIOCHEMISTRY (MOSCOW) 2018; 83:1289-1298. [PMID: 30482142 DOI: 10.1134/s0006297918110019] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
CDKN2A is one of the most studied tumor suppressor genes. It encodes the p16-INK4a protein that plays a critical role in the cell cycle progression, differentiation, senescence, and apoptosis. Mutations in CDKN2A or dysregulation of its functional activity are frequently associated with various types of human cancer. As a cyclin-dependent kinase inhibitor, p16-INK4a forms a complex with cyclin-dependent kinases 4/6 (CDK4/6) thereby competing with cyclin D. It is believed that the helix-turn-helix structures in the content of tandem ankyrin repeats in p16-INK4a are required for the protein interaction with CDK4. Until recently, the mechanisms considered to be involved in the regulation of p16-INK4a functions and cancer development have been mutations in DNA, homozygous or heterozygous gene loss, and methylation of CDKN2A promoter region. In this review, we discuss recent findings on the regulation of p16-INK4a by covalent modifications at both transcriptional and post-translational levels.
Collapse
Affiliation(s)
- Yang Jiao
- School of Physical Education, Northeast Normal University, Changchun, Jilin, 130024, P. R. China
| | - Yunpeng Feng
- Key Laboratory of Molecular Epigenetics, Ministry of Education, Northeast Normal University, Changchun, Jilin, 130024, P. R. China
| | - Xiuli Wang
- Central Laboratory of General Biology, School of Life Sciences, Northeast Normal University, Changchun, Jilin, 130024, P. R. China.
| |
Collapse
|
49
|
Mao SQ, Ghanbarian AT, Spiegel J, Martínez Cuesta S, Beraldi D, Di Antonio M, Marsico G, Hänsel-Hertsch R, Tannahill D, Balasubramanian S. DNA G-quadruplex structures mold the DNA methylome. Nat Struct Mol Biol 2018; 25:951-957. [PMID: 30275516 PMCID: PMC6173298 DOI: 10.1038/s41594-018-0131-8] [Citation(s) in RCA: 152] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 08/08/2018] [Indexed: 12/15/2022]
Abstract
Control of DNA methylation level is critical for gene regulation, and the factors that govern hypomethylation at CpG islands (CGIs) are still being uncovered. Here, we provide evidence that G-quadruplex (G4) DNA secondary structures are genomic features that influence methylation at CGIs. We show that the presence of G4 structure is tightly associated with CGI hypomethylation in the human genome. Surprisingly, we find that these G4 sites are enriched for DNA methyltransferase 1 (DNMT1) occupancy, which is consistent with our biophysical observations that DNMT1 exhibits higher binding affinity for G4s as compared to duplex, hemi-methylated, or single-stranded DNA. The biochemical assays also show that the G4 structure itself, rather than sequence, inhibits DNMT1 enzymatic activity. Based on these data, we propose that G4 formation sequesters DNMT1 thereby protecting certain CGIs from methylation and inhibiting local methylation.
Collapse
Affiliation(s)
- Shi-Qing Mao
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
| | - Avazeh T Ghanbarian
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
- European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Hinxton, UK
| | - Jochen Spiegel
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
| | - Sergio Martínez Cuesta
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Dario Beraldi
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
| | | | - Giovanni Marsico
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
| | | | - David Tannahill
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
| | - Shankar Balasubramanian
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK.
- Department of Chemistry, University of Cambridge, Cambridge, UK.
- School of Clinical Medicine, University of Cambridge, Cambridge, UK.
| |
Collapse
|
50
|
Du J, Kirk B, Zeng J, Ma J, Wang Q. Three classes of response elements for human PRC2 and MLL1/2-Trithorax complexes. Nucleic Acids Res 2018; 46:8848-8864. [PMID: 29992232 PMCID: PMC6158500 DOI: 10.1093/nar/gky595] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 06/19/2018] [Accepted: 06/21/2018] [Indexed: 12/15/2022] Open
Abstract
Polycomb group (PcG) and Trithorax group (TrxG) proteins are essential for maintaining epigenetic memory in both embryonic stem cells and differentiated cells. To date, how they are localized to hundreds of specific target genes within a vertebrate genome had remained elusive. Here, by focusing on short cis-acting DNA elements of single functions, we discovered three classes of response elements in human genome: Polycomb response elements (PREs), Trithorax response elements (TREs) and Polycomb/Trithorax response elements (P/TREs). In particular, the four PREs (PRE14, 29, 39 and 48) are the first set of, to our knowledge, bona fide vertebrate PREs ever discovered, while many previously reported Drosophila or vertebrate PREs are likely P/TREs. We further demonstrated that YY1 and CpG islands are specifically enriched in the four TREs (PRE30, 41, 44 and 55), but not in the PREs. The three classes of response elements as unraveled in this study should guide further global investigation and open new doors for a deeper understanding of PcG and TrxG mechanisms in vertebrates.
Collapse
Affiliation(s)
- Junqing Du
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Brian Kirk
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jia Zeng
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jianpeng Ma
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77030, USA
| | - Qinghua Wang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| |
Collapse
|