1
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Kawase M, Ichiyanagi K. Mouse retrotransposons: sequence structure, evolutionary age, genomic distribution and function. Genes Genet Syst 2024; 98:337-351. [PMID: 37989301 DOI: 10.1266/ggs.23-00221] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023] Open
Abstract
Retrotransposons are transposable elements that are transposed via transcription and reverse transcription. Their copies have accumulated in the genome of mammals, occupying approximately 40% of mammalian genomic mass. These copies are often involved in numerous phenomena, such as chromatin spatial organization, gene expression, development and disease, and have been recognized as a driving force in evolution. Different organisms have gained specific retrotransposon subfamilies and retrotransposed copies, such as hundreds of Mus-specific subfamilies with diverse sequences and genomic locations. Despite this complexity, basic information is still necessary for present-day genomic and epigenomic studies. Herein, we describe the characteristics of each subfamily of Mus-specific retrotransposons in terms of sequence structure, phylogenetic relationships, evolutionary age, and preference for A or B compartments of chromatin.
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Affiliation(s)
- Masaki Kawase
- Laboratory of Genome and Epigenome Dynamics, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University
| | - Kenji Ichiyanagi
- Laboratory of Genome and Epigenome Dynamics, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University
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2
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Lu X. Regulation of endogenous retroviruses in murine embryonic stem cells and early embryos. J Mol Cell Biol 2024; 15:mjad052. [PMID: 37604781 PMCID: PMC10794949 DOI: 10.1093/jmcb/mjad052] [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: 06/08/2022] [Revised: 11/24/2022] [Accepted: 08/19/2023] [Indexed: 08/23/2023] Open
Abstract
Endogenous retroviruses (ERVs) are important components of transposable elements that constitute ∼40% of the mouse genome. ERVs exhibit dynamic expression patterns during early embryonic development and are engaged in numerous biological processes. Therefore, ERV expression must be closely monitored in cells. Most studies have focused on the regulation of ERV expression in mouse embryonic stem cells (ESCs) and during early embryonic development. This review touches on the classification, expression, and functions of ERVs in mouse ESCs and early embryos and mainly discusses ERV modulation strategies from the perspectives of transcription, epigenetic modification, nucleosome/chromatin assembly, and post-transcriptional control.
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Affiliation(s)
- Xinyi Lu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, China
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3
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Gerdes P, Chan D, Lundberg M, Sanchez-Luque FJ, Bodea GO, Ewing AD, Faulkner GJ, Richardson SR. Locus-resolution analysis of L1 regulation and retrotransposition potential in mouse embryonic development. Genome Res 2023; 33:1465-1481. [PMID: 37798118 PMCID: PMC10620060 DOI: 10.1101/gr.278003.123] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/21/2023] [Indexed: 10/07/2023]
Abstract
Mice harbor ∼2800 intact copies of the retrotransposon Long Interspersed Element 1 (L1). The in vivo retrotransposition capacity of an L1 copy is defined by both its sequence integrity and epigenetic status, including DNA methylation of the monomeric units constituting young mouse L1 promoters. Locus-specific L1 methylation dynamics during development may therefore elucidate and explain spatiotemporal niches of endogenous retrotransposition but remain unresolved. Here, we interrogate the retrotransposition efficiency and epigenetic fate of source (donor) L1s, identified as mobile in vivo. We show that promoter monomer loss consistently attenuates the relative retrotransposition potential of their offspring (daughter) L1 insertions. We also observe that most donor/daughter L1 pairs are efficiently methylated upon differentiation in vivo and in vitro. We use Oxford Nanopore Technologies (ONT) long-read sequencing to resolve L1 methylation genome-wide and at individual L1 loci, revealing a distinctive "smile" pattern in methylation levels across the L1 promoter region. Using Pacific Biosciences (PacBio) SMRT sequencing of L1 5' RACE products, we then examine DNA methylation dynamics at the mouse L1 promoter in parallel with transcription start site (TSS) distribution at locus-specific resolution. Together, our results offer a novel perspective on the interplay between epigenetic repression, L1 evolution, and genome stability.
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Affiliation(s)
- Patricia Gerdes
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
| | - Dorothy Chan
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
| | - Mischa Lundberg
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
- The University of Queensland Diamantina Institute, The University of Queensland, Woolloongabba, Queensland 4102, Australia
- Translational Bioinformatics, Commonwealth Scientific and Industrial Research Organisation, Sydney, New South Wales 2113, Australia
| | - Francisco J Sanchez-Luque
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
- GENYO. Centre for Genomics and Oncological Research (Pfizer-University of Granada-Andalusian Regional Government), PTS Granada, 18016, Spain
- MRC Human Genetics Unit, Institute of Genetics and Cancer (IGC), University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, United Kingdom
| | - Gabriela O Bodea
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Adam D Ewing
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
| | - Geoffrey J Faulkner
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia;
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Sandra R Richardson
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia;
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4
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Epigenetic mechanisms of Strip2 in differentiation of pluripotent stem cells. Cell Death Dis 2022; 8:447. [PMID: 36335090 PMCID: PMC9637104 DOI: 10.1038/s41420-022-01237-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/18/2022] [Accepted: 10/21/2022] [Indexed: 11/07/2022]
Abstract
Significant evidence points to Strip2 being a key regulator of the differentiation processes of pluripotent embryonic stem cells. However, Strip2 mediated epigenetic regulation of embryonic differentiation and development is quite unknown. Here, we identified several interaction partners of Strip2, importantly the co-repressor molecular protein complex nucleosome remodeling deacetylase/Tripartite motif-containing 28/Histone deacetylases/Histone-lysine N-methyltransferase SETDB1 (NuRD/TRIM28/HDACs/SETDB1) histone methyltransferase, which is primarily involved in regulation of the pluripotency of embryonic stem cells and its differentiation. The complex is normally activated by binding of Krueppel-associated box zinc-finger proteins (KRAB-ZFPs) to specific DNA motifs, causing methylation of H3 to Lysin-9 residues (H3K9). Our data showed that Strip2 binds to a DNA motif (20 base pairs), like the KRAB-ZFPs. We establish that Strip2 is an epigenetic regulator of pluripotency and differentiation by modulating DNA KRAB-ZFPs as well as the NuRD/TRIM28/HDACs/SETDB1 histone methyltransferase complex.
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5
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Fernandes LP, Enriquez-Gasca R, Gould PA, Holt JH, Conde L, Ecco G, Herrero J, Gifford R, Trono D, Kassiotis G, Rowe HM. A satellite DNA array barcodes chromosome 7 and regulates totipotency via ZFP819. SCIENCE ADVANCES 2022; 8:eabp8085. [PMID: 36306355 PMCID: PMC9616502 DOI: 10.1126/sciadv.abp8085] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 09/08/2022] [Indexed: 06/11/2023]
Abstract
Mammalian genomes are a battleground for genetic conflict between repetitive elements and KRAB-zinc finger proteins (KZFPs). We asked whether KZFPs can regulate cell fate by using ZFP819, which targets a satellite DNA array, ZP3AR. ZP3AR coats megabase regions of chromosome 7 encompassing genes encoding ZSCAN4, a master transcription factor of totipotency. Depleting ZFP819 in mouse embryonic stem cells (mESCs) causes them to transition to a 2-cell (2C)-like state, whereby the ZP3AR array switches from a poised to an active enhancer state. This is accompanied by a global erosion of heterochromatin roadblocks, which we link to decreased SETDB1 stability. These events result in transcription of active LINE-1 elements and impaired differentiation. In summary, ZFP819 and TRIM28 partner up to close chromatin across Zscan4, to promote exit from totipotency. We propose that satellite DNAs may control developmental fate transitions by barcoding and switching off master transcription factor genes.
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Affiliation(s)
- Liane P. Fernandes
- Centre for Immunobiology, Blizard Institute, Queen Mary University of London, London E1 2AT, UK
| | - Rocio Enriquez-Gasca
- Centre for Immunobiology, Blizard Institute, Queen Mary University of London, London E1 2AT, UK
| | - Poppy A. Gould
- Centre for Immunobiology, Blizard Institute, Queen Mary University of London, London E1 2AT, UK
| | - James H. Holt
- Centre for Immunobiology, Blizard Institute, Queen Mary University of London, London E1 2AT, UK
| | - Lucia Conde
- Bill Lyons Informatics Centre, UCL Cancer Institute, London WC1E 6BT, UK
| | - Gabriela Ecco
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Javier Herrero
- Bill Lyons Informatics Centre, UCL Cancer Institute, London WC1E 6BT, UK
| | - Robert Gifford
- MRC–University of Glasgow Centre for Virus Research, Glasgow, UK
| | - Didier Trono
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | | | - Helen M. Rowe
- Centre for Immunobiology, Blizard Institute, Queen Mary University of London, London E1 2AT, UK
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6
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Dopkins N, O’Mara MM, Lawrence E, Fei T, Sandoval-Motta S, Nixon DF, Bendall ML. A field guide to endogenous retrovirus regulatory networks. Mol Cell 2022; 82:3763-3768. [DOI: 10.1016/j.molcel.2022.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/15/2022] [Accepted: 09/08/2022] [Indexed: 11/06/2022]
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7
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Zhang Q, Pan J, Cong Y, Mao J. Transcriptional Regulation of Endogenous Retroviruses and Their Misregulation in Human Diseases. Int J Mol Sci 2022; 23:ijms231710112. [PMID: 36077510 PMCID: PMC9456331 DOI: 10.3390/ijms231710112] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/28/2022] [Accepted: 09/01/2022] [Indexed: 11/22/2022] Open
Abstract
Endogenous retroviruses (ERVs), deriving from exogenous retroviral infections of germ line cells occurred millions of years ago, represent ~8% of human genome. Most ERVs are highly inactivated because of the accumulation of mutations, insertions, deletions, and/or truncations. However, it is becoming increasingly apparent that ERVs influence host biology through genetic and epigenetic mechanisms under particular physiological and pathological conditions, which provide both beneficial and deleterious effects for the host. For instance, certain ERVs expression is essential for human embryonic development. Whereas abnormal activation of ERVs was found to be involved in numbers of human diseases, such as cancer and neurodegenerative diseases. Therefore, understanding the mechanisms of regulation of ERVs would provide insights into the role of ERVs in health and diseases. Here, we provide an overview of mechanisms of transcriptional regulation of ERVs and their dysregulation in human diseases.
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8
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Di Stefano L. All Quiet on the TE Front? The Role of Chromatin in Transposable Element Silencing. Cells 2022; 11:cells11162501. [PMID: 36010577 PMCID: PMC9406493 DOI: 10.3390/cells11162501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/27/2022] [Accepted: 08/03/2022] [Indexed: 01/09/2023] Open
Abstract
Transposable elements (TEs) are mobile genetic elements that constitute a sizeable portion of many eukaryotic genomes. Through their mobility, they represent a major source of genetic variation, and their activation can cause genetic instability and has been linked to aging, cancer and neurodegenerative diseases. Accordingly, tight regulation of TE transcription is necessary for normal development. Chromatin is at the heart of TE regulation; however, we still lack a comprehensive understanding of the precise role of chromatin marks in TE silencing and how chromatin marks are established and maintained at TE loci. In this review, I discuss evidence documenting the contribution of chromatin-associated proteins and histone marks in TE regulation across different species with an emphasis on Drosophila and mammalian systems.
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Affiliation(s)
- Luisa Di Stefano
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France
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9
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Kabi M, Filion GJ. Chromatin and viral integration in immunity: The challenge of silencing non-self genes. Trends Immunol 2022; 43:449-458. [PMID: 35490134 DOI: 10.1016/j.it.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/03/2022] [Accepted: 04/04/2022] [Indexed: 11/24/2022]
Abstract
Several viruses hide in the genome of their host. To complete their replication cycle, they need to integrate in the form of a provirus and express their genes. In vertebrates, integrated viruses can be silenced by chromatin, implying that some specific mechanisms exist to detect non-self genes. The known mechanisms depend on sequence features of retroelements, but the fluctuations of virus expression suggest that other determinants also exist. Here we review the mechanisms allowing chromatin to silence integrated viruses and propose that DNA repair may help flag them as 'non-self' shortly after their genomic insertion.
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Affiliation(s)
- Manisha Kabi
- Department of Biological Sciences, University of Toronto Scarborough, Scarborough, ON, Canada
| | - Guillaume J Filion
- Department of Biological Sciences, University of Toronto Scarborough, Scarborough, ON, Canada.
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10
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Adhikari UK, Sakiz E, Habiba U, Mikhael M, Senesi M, David MA, Guillemin GJ, Ooi L, Karl T, Collins S, Tayebi M. Treatment of microglia with Anti-PrP monoclonal antibodies induces neuronal apoptosis in vitro. Heliyon 2021; 7:e08644. [PMID: 35005289 PMCID: PMC8715334 DOI: 10.1016/j.heliyon.2021.e08644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/23/2021] [Accepted: 12/16/2021] [Indexed: 11/04/2022] Open
Abstract
Previous reports highlighted the neurotoxic effects caused by some motif-specific anti-PrPC antibodies in vivo and in vitro. In the current study, we investigated the detailed alterations of the proteome with liquid chromatography–mass spectrometry following direct application of anti-PrPC antibodies on mouse neuroblastoma cells (N2a) and mouse primary neuronal (MPN) cells or by cross-linking microglial PrPC with anti-PrPC antibodies prior to co-culture with the N2a/MPN cells. Here, we identified 4 (3 upregulated and 1 downregulated) and 17 (11 upregulated and 6 downregulated) neuronal apoptosis-related proteins following treatment of the N2a and N11 cell lines respectively when compared with untreated cells. In contrast, we identified 1 (upregulated) and 4 (2 upregulated and 2 downregulated) neuronal apoptosis-related proteins following treatment of MPN cells and N11 when compared with untreated cells. Furthermore, we also identified 3 (2 upregulated and 1 downregulated) and 2 (1 upregulated and 1 downregulated) neuronal apoptosis-related related proteins following treatment of MPN cells and N11 when compared to treatment with an anti-PrP antibody that lacks binding specificity for mouse PrP. The apoptotic effect of the anti-PrP antibodies was confirmed with flow cytometry following labelling of Annexin V-FITC. The toxic effects of the anti-PrP antibodies was more intense when antibody-treated N11 were co-cultured with the N2a and the identified apoptosis proteome was shown to be part of the PrPC-interactome. Our observations provide a new insight into the prominent role played by microglia in causing neurotoxic effects following treatment with anti-PrPC antibodies and might be relevant to explain the antibody mediated toxicity observed in other related neurodegenerative diseases such as Alzheimer. Antibody cross-linking neuronal PrPC induces apoptosis. Antibody cross-linking microglial PrPC induces neuronal apoptosis. Different apoptotic pathways were triggered by specific anti-PrP antibody treatments.
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11
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Dechaud C, Volff JN, Schartl M, Naville M. Sex and the TEs: transposable elements in sexual development and function in animals. Mob DNA 2019; 10:42. [PMID: 31700550 PMCID: PMC6825717 DOI: 10.1186/s13100-019-0185-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 10/21/2019] [Indexed: 12/23/2022] Open
Abstract
Transposable elements are endogenous DNA sequences able to integrate into and multiply within genomes. They constitute a major source of genetic innovations, as they can not only rearrange genomes but also spread ready-to-use regulatory sequences able to modify host gene expression, and even can give birth to new host genes. As their evolutionary success depends on their vertical transmission, transposable elements are intrinsically linked to reproduction. In organisms with sexual reproduction, this implies that transposable elements have to manifest their transpositional activity in germ cells or their progenitors. The control of sexual development and function can be very versatile, and several studies have demonstrated the implication of transposable elements in the evolution of sex. In this review, we report the functional and evolutionary relationships between transposable elements and sexual reproduction in animals. In particular, we highlight how transposable elements can influence expression of sexual development genes, and how, reciprocally, they are tightly controlled in gonads. We also review how transposable elements contribute to the organization, expression and evolution of sexual development genes and sex chromosomes. This underscores the intricate co-evolution between host functions and transposable elements, which regularly shift from a parasitic to a domesticated status useful to the host.
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Affiliation(s)
- Corentin Dechaud
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d’Italie, F-69364 Lyon, France
| | - Jean-Nicolas Volff
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d’Italie, F-69364 Lyon, France
| | - Manfred Schartl
- Entwicklungsbiochemie, Biozentrum, Universität Würzburg, Würzburg, Germany
- The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX USA
| | - Magali Naville
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d’Italie, F-69364 Lyon, France
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12
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Illum LRH, Bak ST, Lund S, Nielsen AL. DNA methylation in epigenetic inheritance of metabolic diseases through the male germ line. J Mol Endocrinol 2018; 60:R39-R56. [PMID: 29203518 DOI: 10.1530/jme-17-0189] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 12/04/2017] [Indexed: 12/26/2022]
Abstract
The global rise in metabolic diseases can be attributed to a complex interplay between biology, behavior and environmental factors. This article reviews the current literature concerning DNA methylation-based epigenetic inheritance (intergenerational and transgenerational) of metabolic diseases through the male germ line. Included are a presentation of the basic principles for DNA methylation in developmental programming, and a description of windows of susceptibility for the inheritance of environmentally induced aberrations in DNA methylation and their associated metabolic disease phenotypes. To this end, escapees, genomic regions with the intrinsic potential to transmit acquired paternal epigenetic information across generations by escaping the extensive programmed DNA demethylation that occurs during gametogenesis and in the zygote, are described. The ongoing descriptive and functional examinations of DNA methylation in the relevant biological samples, in conjugation with analyses of non-coding RNA and histone modifications, hold promise for improved delineation of the effect size and mechanistic background for epigenetic inheritance of metabolic diseases.
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Affiliation(s)
| | - Stine Thorhauge Bak
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Clinical Medicine, Endocrinology and Diabetes, Aarhus University Hospital, Aarhus, Denmark
| | - Sten Lund
- Department of Clinical Medicine, Endocrinology and Diabetes, Aarhus University Hospital, Aarhus, Denmark
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13
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Wu X, Dao Thi VL, Huang Y, Billerbeck E, Saha D, Hoffmann HH, Wang Y, Silva LAV, Sarbanes S, Sun T, Andrus L, Yu Y, Quirk C, Li M, MacDonald MR, Schneider WM, An X, Rosenberg BR, Rice CM. Intrinsic Immunity Shapes Viral Resistance of Stem Cells. Cell 2017; 172:423-438.e25. [PMID: 29249360 DOI: 10.1016/j.cell.2017.11.018] [Citation(s) in RCA: 226] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 09/11/2017] [Accepted: 11/09/2017] [Indexed: 12/26/2022]
Abstract
Stem cells are highly resistant to viral infection compared to their differentiated progeny; however, the mechanism is mysterious. Here, we analyzed gene expression in mammalian stem cells and cells at various stages of differentiation. We find that, conserved across species, stem cells express a subset of genes previously classified as interferon (IFN) stimulated genes (ISGs) but that expression is intrinsic, as stem cells are refractory to interferon. This intrinsic ISG expression varies in a cell-type-specific manner, and many ISGs decrease upon differentiation, at which time cells become IFN responsive, allowing induction of a broad spectrum of ISGs by IFN signaling. Importantly, we show that intrinsically expressed ISGs protect stem cells against viral infection. We demonstrate the in vivo importance of intrinsic ISG expression for protecting stem cells and their differentiation potential during viral infection. These findings have intriguing implications for understanding stem cell biology and the evolution of pathogen resistance.
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Affiliation(s)
- Xianfang Wu
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Viet Loan Dao Thi
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Yumin Huang
- Laboratory of Membrane Biology, New York Blood Center, New York, NY 10065, USA; Department of Hematology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Eva Billerbeck
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Debjani Saha
- Program in Immunogenomics, The Rockefeller University, New York, NY 10065, USA
| | - Hans-Heinrich Hoffmann
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Yaomei Wang
- Laboratory of Membrane Biology, New York Blood Center, New York, NY 10065, USA; School of Life Sciences, Zhengzhou University, Zhengzhou, Henan 450001, China
| | | | - Stephanie Sarbanes
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Tony Sun
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Linda Andrus
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Yingpu Yu
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Corrine Quirk
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Melody Li
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Margaret R MacDonald
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - William M Schneider
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Xiuli An
- Laboratory of Membrane Biology, New York Blood Center, New York, NY 10065, USA; School of Life Sciences, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Brad R Rosenberg
- Program in Immunogenomics, The Rockefeller University, New York, NY 10065, USA
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA.
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14
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Shimosuga KI, Fukuda K, Sasaki H, Ichiyanagi K. Locus-specific hypomethylation of the mouse IAP retrotransposon is associated with transcription factor-binding sites. Mob DNA 2017; 8:20. [PMID: 29255492 PMCID: PMC5729234 DOI: 10.1186/s13100-017-0105-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 12/01/2017] [Indexed: 01/23/2023] Open
Abstract
Background Intracisternal A particle (IAP) is one of the most transpositionally active retrotransposons in the mouse genome, but its expression varies between cell types. This variation is believed to arise from differences in the epigenetic state (e.g., DNA methylation) of the 5′ long terminal repeat (LTR), where transcription starts. However, owing to the high copy number and high sequence similarity between copies, it is difficult to analyze the epigenetic states of individual IAP LTRs in a comprehensive manner. Results We have developed a method called Target Enrichment after Post-Bisulfite Adaptor Tagging (TEPBAT) to analyze the DNA methylation states of a large number of individual retrotransposon copies at once. Using this method, we determined the DNA methylation levels of >8500 copies of genomic IAP LTRs (almost all copies that we aimed to target by the PCR primers) in the sperm and tail. This revealed that the vast majority of the LTRs were heavily methylated in both sperm and tail; however, hypomethylated copies were more frequently found in the sperm than in the tail. Interestingly, most of these hypomethylated LTRs were solo-type, belonged to specific IAP subfamilies, and carried binding sites for transcription factors (TFs) that are active in male germ cells. Conclusions The current study revealed subfamily- and locus-specific hypomethylation of IAP LTRs, and suggests that binding of TFs is involved in the protection from DNA methylation, whereas the IAP internal sequence enhances methylation. Furthermore, the study demonstrated that TEPBAT offers a cost-effective method for a variety of DNA methylome studies that focus on retrotransposon sequences. Electronic supplementary material The online version of this article (10.1186/s13100-017-0105-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ken-Ichi Shimosuga
- Division of Epigenomics and Development, Medical Institute of Bioregulation, and Epigenome Network Research Center, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582 Japan.,Trygroup Incorporated, 1-8-10 Kudankita, Chiyoda-ku, Tokyo, 102-0073 Japan
| | - Kei Fukuda
- Division of Epigenomics and Development, Medical Institute of Bioregulation, and Epigenome Network Research Center, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582 Japan.,Cellular Memory Laboratory, RIKEN, Wako, Saitama, 351-0198 Japan
| | - Hiroyuki Sasaki
- Division of Epigenomics and Development, Medical Institute of Bioregulation, and Epigenome Network Research Center, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582 Japan
| | - Kenji Ichiyanagi
- Division of Epigenomics and Development, Medical Institute of Bioregulation, and Epigenome Network Research Center, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582 Japan.,Laboratory of Genome and Epigenome Dynamics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
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15
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TRIM28 and Interacting KRAB-ZNFs Control Self-Renewal of Human Pluripotent Stem Cells through Epigenetic Repression of Pro-differentiation Genes. Stem Cell Reports 2017; 9:2065-2080. [PMID: 29198826 PMCID: PMC5785758 DOI: 10.1016/j.stemcr.2017.10.031] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 10/31/2017] [Accepted: 10/31/2017] [Indexed: 11/20/2022] Open
Abstract
Reprogramming to induced pluripotent stem cells (iPSCs) and differentiation of pluripotent stem cells (PSCs) are regulated by epigenetic machinery. Tripartite motif protein 28 (TRIM28), a universal mediator of Krüppel-associated box domain zinc fingers (KRAB-ZNFs), is known to regulate both processes; however, the exact mechanism and identity of participating KRAB-ZNF genes remain unknown. Here, using a reporter system, we show that TRIM28/KRAB-ZNFs alter DNA methylation patterns in addition to H3K9me3 to cause stable gene repression during reprogramming. Using several expression datasets, we identified KRAB-ZNFs (ZNF114, ZNF483, ZNF589) in the human genome that maintain pluripotency. Moreover, we identified target genes repressed by these KRAB-ZNFs. Mechanistically, we demonstrated that these KRAB-ZNFs directly alter gene expression of important developmental genes by modulating H3K9me3 and DNA methylation of their promoters. In summary, TRIM28 employs KRAB-ZNFs to evoke epigenetic silencing of its target differentiation genes via H3K9me3 and DNA methylation. Upon reprogramming KRAB-repressor evokes stable silencing of its target genes KRAB-ZNFs repress target genes required for differentiation of pluripotent cells KRAB-ZNFs are crucial for the maintenance of pluripotency of human stem cells TRIM28/KRAB-ZNFs repress developmental genes through H3K9 and de novo DNA methylation
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16
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Czerwińska P, Mazurek S, Wiznerowicz M. The complexity of TRIM28 contribution to cancer. J Biomed Sci 2017; 24:63. [PMID: 28851455 PMCID: PMC5574234 DOI: 10.1186/s12929-017-0374-4] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/24/2017] [Indexed: 01/07/2023] Open
Abstract
Since the first discovery in 1996, the engagement of TRIM28 in distinct aspects of cellular biology has been extensively studied resulting in identification of a complex nature of TRIM28 protein. In this review, we summarize core biological functions of TRIM28 that emerge from TRIM28 multi-domain structure and possessed enzymatic activities. Moreover, we will discuss whether the complexity of TRIM28 engagement in cancer biology makes TRIM28 a possible candidate for targeted anti-cancer therapy. Briefly, we will demonstrate the role of TRIM28 in regulation of target gene transcription, response to DNA damage, downregulation of p53 activity, stimulation of epithelial-to-mesenchymal transition, stemness sustainability, induction of autophagy and regulation of retrotransposition, to provide the answer whether TRIM28 functions as a stimulator or inhibitor of tumorigenesis. To date, number of studies demonstrate significant upregulation of TRIM28 expression in cancer tissues which correlates with worse overall patient survival, suggesting that TRIM28 supports cancer progression. Here, we present distinct aspects of TRIM28 involvement in regulation of cancer cell homeostasis which collectively imply pro-tumorigenic character of TRIM28. Thorough analyses are further needed to verify whether TRIM28 possess the potential to become a new anti-cancer target.
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Affiliation(s)
- Patrycja Czerwińska
- Laboratory of Gene Therapy, Department of Diagnostics and Cancer Immunology, Greater Poland Cancer Centre, 15 Garbary Street, 61-866, Poznan, Poland. .,Department of Cancer Immunology, Chair of Medical Biotechnology, Poznan University of Medical Sciences, Poznan, Poland.
| | - Sylwia Mazurek
- Laboratory of Gene Therapy, Department of Diagnostics and Cancer Immunology, Greater Poland Cancer Centre, 15 Garbary Street, 61-866, Poznan, Poland.,Department of Cancer Immunology, Chair of Medical Biotechnology, Poznan University of Medical Sciences, Poznan, Poland.,Postgraduate School of Molecular Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Maciej Wiznerowicz
- Laboratory of Gene Therapy, Department of Diagnostics and Cancer Immunology, Greater Poland Cancer Centre, 15 Garbary Street, 61-866, Poznan, Poland.,Department of Cancer Immunology, Chair of Medical Biotechnology, Poznan University of Medical Sciences, Poznan, Poland
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17
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LTR-Retrotransposon Control by tRNA-Derived Small RNAs. Cell 2017; 170:61-71.e11. [PMID: 28666125 DOI: 10.1016/j.cell.2017.06.013] [Citation(s) in RCA: 256] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 04/13/2017] [Accepted: 05/09/2017] [Indexed: 12/31/2022]
Abstract
Transposon reactivation is an inherent danger in cells that lose epigenetic silencing during developmental reprogramming. In the mouse, long terminal repeat (LTR)-retrotransposons, or endogenous retroviruses (ERV), account for most novel insertions and are expressed in the absence of histone H3 lysine 9 trimethylation in preimplantation stem cells. We found abundant 18 nt tRNA-derived small RNA (tRF) in these cells and ubiquitously expressed 22 nt tRFs that include the 3' terminal CCA of mature tRNAs and target the tRNA primer binding site (PBS) essential for ERV reverse transcription. We show that the two most active ERV families, IAP and MusD/ETn, are major targets and are strongly inhibited by tRFs in retrotransposition assays. 22 nt tRFs post-transcriptionally silence coding-competent ERVs, while 18 nt tRFs specifically interfere with reverse transcription and retrotransposon mobility. The PBS offers a unique target to specifically inhibit LTR-retrotransposons, and tRF-targeting is a potentially highly conserved mechanism of small RNA-mediated transposon control.
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18
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Groh S, Schotta G. Silencing of endogenous retroviruses by heterochromatin. Cell Mol Life Sci 2017; 74:2055-2065. [PMID: 28160052 PMCID: PMC11107624 DOI: 10.1007/s00018-017-2454-8] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 12/14/2016] [Accepted: 01/03/2017] [Indexed: 02/05/2023]
Abstract
Endogenous retroviruses (ERV) are an abundant class of repetitive elements in mammalian genomes. To ensure genomic stability, ERVs are largely transcriptionally silent. However, these elements also feature physiological roles in distinct developmental contexts, under which silencing needs to be partially relieved. ERV silencing is mediated through a heterochromatic structure, which is established by histone modification and DNA methylation machineries. This heterochromatic structure is largely refractory to transcriptional stimulation, however, challenges to the heterochromatic state, such as DNA replication, require re-establishment of the heterochromatic state in competition with transcriptional activators. In this review, we discuss the major pathways leading to efficient establishment of robust and inaccessible heterochromatin across ERVs.
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Affiliation(s)
- Sophia Groh
- Biomedical Center and Center for Integrated Protein Science Munich, Ludwig-Maximilians-University, 82152, Planegg-Martinsried, Germany
| | - Gunnar Schotta
- Biomedical Center and Center for Integrated Protein Science Munich, Ludwig-Maximilians-University, 82152, Planegg-Martinsried, Germany.
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19
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Discovery of a novel oocyte-specific Krüppel-associated box domain-containing zinc finger protein required for early embryogenesis in cattle. Mech Dev 2017; 144:103-112. [PMID: 28263788 DOI: 10.1016/j.mod.2017.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 02/09/2017] [Accepted: 02/20/2017] [Indexed: 12/17/2022]
Abstract
Zinc finger (ZNF) transcription factors interact with DNA through zinc finger motifs and play important roles in a variety of cellular functions including cell growth, proliferation, development, apoptosis, and intracellular signal transduction. One-third of ZNF proteins in metazoans contain a highly conserved N-terminal motif known as the Krüppel-associated box (KRAB) domain, which acts as a potent, DNA-binding dependent transcriptional repression module. Analysis of RNA-Seq data generated from a bovine oocyte cDNA library identified a novel transcript, which encodes a KRAB-containing ZNF transcription factor (named ZNFO). Characterization of ZNFO mRNA expression revealed that it is exclusively expressed in bovine oocytes and early embryos. A GFP reporter assay demonstrated that ZNFO protein localizes specifically to the nucleus, supporting its role in transcriptional regulation. To test the role of ZNFO in early embryonic development, zygotes were generated by in vitro maturation and fertilization of oocytes, and injected with small interfering RNA (siRNA) designed to knockdown ZNFO. Cleavage rates were not affected by ZNFO siRNA injection. However, embryonic development to 8- to 16-cell stage and blastocyst stage was significantly reduced relative to the uninjected and negative control siRNA-injected embryos. Further, interaction of ZNFO with the highly conserved co-factor, KRAB-associated protein-1 (KAP1), was demonstrated, and evidence supporting transcriptional repression by ZNFO was demonstrated using a GAL4-luciferase reporter system. Results of described studies demonstrate that ZNFO is a maternally-derived oocyte-specific nuclear factor required for early embryonic development in cattle, presumably functioning by repressing transcription.
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20
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Gerdes P, Richardson SR, Faulkner GJ. TET enzymes: double agents in the transposable element-host genome conflict. Genome Biol 2016; 17:259. [PMID: 27993162 PMCID: PMC5170891 DOI: 10.1186/s13059-016-1124-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The mouse genome is replete with retrotransposon sequences, from evolutionarily young elements with mutagenic potential that must be controlled, to inactive molecular fossils whose sequences can be domesticated over evolutionary time to benefit the host genome. In an exciting new study, de la Rica and colleagues have uncovered a complex relationship between ten-eleven translocation (TET) proteins and retrotransposons in mouse embryonic stem cells (ESCs), implicating TETs as enhancers in the exaptation and function of retroelement sequences. Furthermore, they have demonstrated that active demethylation of retrotransposons does not correlate with their increased expression in ESCs, calling into question long-held assumptions regarding the importance of DNA demethylation for retrotransposon expression, and revealing novel epigenetic players in retrotransposon control. Please see related Research article: http://genomebiology.biomedcentral.com/articles/10.1186/s13059-016-1096-8
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Affiliation(s)
- Patricia Gerdes
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Sandra R Richardson
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Geoffrey J Faulkner
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia. .,School of Biomedical Sciences, University of Queensland, Brisbane, QLD 4072, Australia. .,Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia.
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21
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Abstract
Retrotransposons have generated about 40 % of the human genome. This review examines the strategies the cell has evolved to coexist with these genomic "parasites", focussing on the non-long terminal repeat retrotransposons of humans and mice. Some of the restriction factors for retrotransposition, including the APOBECs, MOV10, RNASEL, SAMHD1, TREX1, and ZAP, also limit replication of retroviruses, including HIV, and are part of the intrinsic immune system of the cell. Many of these proteins act in the cytoplasm to degrade retroelement RNA or inhibit its translation. Some factors act in the nucleus and involve DNA repair enzymes or epigenetic processes of DNA methylation and histone modification. RISC and piRNA pathway proteins protect the germline. Retrotransposon control is relaxed in some cell types, such as neurons in the brain, stem cells, and in certain types of disease and cancer, with implications for human health and disease. This review also considers potential pitfalls in interpreting retrotransposon-related data, as well as issues to consider for future research.
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Affiliation(s)
- John L. Goodier
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA 212051
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22
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Ichida Y, Utsunomiya Y, Onodera M. Effect of the linkers between the zinc fingers in zinc finger protein 809 on gene silencing and nuclear localization. Biochem Biophys Res Commun 2016; 471:533-8. [PMID: 26879141 DOI: 10.1016/j.bbrc.2016.02.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 02/11/2016] [Indexed: 10/22/2022]
Abstract
Zinc finger protein 809 (ZFP809) belongs to the Kruppel-associated box-containing zinc finger protein (KRAB-ZFP) family and functions in repressing the expression of Moloney murine leukemia virus (MoMLV). ZFP809 binds to the primer-binding site (PBS)located downstream of the MoMLV-long terminal repeat (LTR) and induces epigenetic modifications at integration sites, such as repressive histone modifications and de novo DNA methylation. KRAB-ZFPs contain consensus TGEKP linkers between C2H2 zinc fingers. The phosphorylation of threonine residues within linkers leads to the inactivation of zinc finger binding to target sequences. ZFP809 also contains consensus linkers between zinc fingers. However, the function of ZFP809 linkers remains unknown. In the present study, we constructed ZFP809 proteins containing mutated linkers and examined their ability to silence transgene expression driven by MLV, binding ability to MLV PBS, and cellular localization. The results of the present study revealed that the linkers affected the ability of ZFP809 to silence transgene expression. Furthermore, this effect could be partly attributed to changes in the localization of ZFP809 proteins containing mutated linkers. Further characterization of ZFP809 linkers is required for understanding the functions and features of KRAB-ZFP-containing linkers.
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Affiliation(s)
- Yu Ichida
- Department of Human Genetics, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535, Japan.
| | - Yuko Utsunomiya
- Department of Human Genetics, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535, Japan
| | - Masafumi Onodera
- Department of Human Genetics, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535, Japan
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23
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Molaro A, Malik HS. Hide and seek: how chromatin-based pathways silence retroelements in the mammalian germline. Curr Opin Genet Dev 2016; 37:51-58. [PMID: 26821364 DOI: 10.1016/j.gde.2015.12.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 12/02/2015] [Accepted: 12/14/2015] [Indexed: 01/07/2023]
Abstract
Retroelements comprise a major fraction of most mammalian genomes. To protect their fitness and stability, hosts must keep retroelements in check in their germline. In most tissues mobile element insertions are decorated with chromatin modifications suggestive of transcriptional silencing. However, germline cells undergo massive chromatin reprogramming events, which erase repressive chromatin marks and necessitate de novo re-establishment of silencing. How do host genomes achieve the discrimination necessary for this de novo silencing? A series of recent studies have revealed aspects of the multi-pronged strategy that mammalian genomes use to identify and silence retroelements. These strategies include the use of small RNA-guides, of specialized DNA-binding protein adaptors and of proteins that repair chromatin discontinuities caused by retroelement insertions. Genetic analyses reveal the importance of these mechanisms of protection, each of which specializes in silencing retroelements of different evolutionary ages. Together, these strategies allow mammalian genomes to withstand the high burden of their parasites.
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Affiliation(s)
- Antoine Molaro
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States
| | - Harmit S Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States; Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States.
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24
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Leseva M, Knowles BB, Messerschmidt DM, Solter D. Erase-Maintain-Establish: Natural Reprogramming of the Mammalian Epigenome. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2016; 80:155-163. [PMID: 26763985 DOI: 10.1101/sqb.2015.80.027441] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The genetic information is largely identical across most cell types in a given organism but the epigenome, which controls expression of the genome, is cell type- and context-dependent. Although most mature mammalian cells appear to have a stable, heritable epigenome, a dynamic intricate process reshapes it as these cells transition from soma to germline and back again. During normal embryogenesis, primordial germ cells, of somatic origin, are set aside to become gametes. In doing so their genome is reprogrammed-that is, the epigenome of specific regions is replaced in a sex-specific fashion as they terminally differentiate into oocytes or spermatocytes in the gonads. Upon union of these gametes, reprogramming of the new organism's epigenome is initiated, which eventually leads, through pluripotent cells, to the cell lineages required for proper embryonic development to a sexually mature adult. This never-ending cycle of birth and rebirth is accomplished through methylation and demethylation of specific genomic sites within the gametes and pluripotent cells of an organism. This enigmatic process of natural epigenomic reprogramming is now being dissected in vivo, focusing on specific genomic regions-that is, imprinted genes and retrotransposons, where TRIM28 molecular complexes appear to guide the transition from gamete to embryo.
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Affiliation(s)
- Milena Leseva
- Department for Developmental Epigenetics and Disease, Institute of Molecular and Cell Biology, A*STAR, 138673 Singapore
| | | | - Daniel M Messerschmidt
- Department for Developmental Epigenetics and Disease, Institute of Molecular and Cell Biology, A*STAR, 138673 Singapore
| | - Davor Solter
- Emeritus Member and Director, Max-Planck Institute of Immunobiology and Epigenetics, 79180 Freiburg, Germany
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25
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Ichida Y, Utsunomiya Y, Onodera M. The third to fifth zinc fingers play an essential role in the binding of ZFP809 to the MLV-derived PBS. Biochem Biophys Res Commun 2016; 469:490-4. [DOI: 10.1016/j.bbrc.2015.12.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 12/08/2015] [Indexed: 01/08/2023]
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26
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Transposable elements at the center of the crossroads between embryogenesis, embryonic stem cells, reprogramming, and long non-coding RNAs. Sci Bull (Beijing) 2015; 60:1722-1733. [PMID: 26543668 PMCID: PMC4624819 DOI: 10.1007/s11434-015-0905-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 09/18/2015] [Indexed: 12/19/2022]
Abstract
Transposable elements (TEs) are mobile genomic sequences of DNA capable of autonomous and non-autonomous duplication. TEs have been highly successful, and nearly half of the human genome now consists of various families of TEs. Originally thought to be non-functional, these elements have been co-opted by animal genomes to perform a variety of physiological functions ranging from TE-derived proteins acting directly in normal biological functions, to innovations in transcription factor logic and influence on epigenetic control of gene expression. During embryonic development, when the genome is epigenetically reprogrammed and DNA-demethylated, TEs are released from repression and show embryonic stage-specific expression, and in human and mouse embryos, intact TE-derived endogenous viral particles can even be detected. A similar process occurs during the reprogramming of somatic cells to pluripotent cells: When the somatic DNA is demethylated, TEs are released from repression. In embryonic stem cells (ESCs), where DNA is hypomethylated, an elaborate system of epigenetic control is employed to suppress TEs, a system that often overlaps with normal epigenetic control of ESC gene expression. Finally, many long non-coding RNAs (lncRNAs) involved in normal ESC function and those assisting or impairing reprogramming contain multiple TEs in their RNA. These TEs may act as regulatory units to recruit RNA-binding proteins and epigenetic modifiers. This review covers how TEs are interlinked with the epigenetic machinery and lncRNAs, and how these links influence each other to modulate aspects of ESCs, embryogenesis, and somatic cell reprogramming.
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27
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Wolf G, Greenberg D, Macfarlan TS. Spotting the enemy within: Targeted silencing of foreign DNA in mammalian genomes by the Krüppel-associated box zinc finger protein family. Mob DNA 2015; 6:17. [PMID: 26435754 PMCID: PMC4592553 DOI: 10.1186/s13100-015-0050-8] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 09/24/2015] [Indexed: 12/17/2022] Open
Abstract
Tandem C2H2-type zinc finger proteins (ZFPs) constitute the largest transcription factor family in animals. Tandem-ZFPs bind DNA in a sequence-specific manner through arrays of multiple zinc finger domains that allow high flexibility and specificity in target recognition. In tetrapods, a large proportion of tandem-ZFPs contain Krüppel-associated-box (KRAB) repression domains, which are able to induce epigenetic silencing through the KAP1 corepressor. The KRAB-ZFP family continuously amplified in tetrapods through segmental gene duplications, often accompanied by deletions, duplications, and mutations of the zinc finger domains. As a result, tetrapod genomes contain unique sets of KRAB-ZFP genes, consisting of ancient and recently evolved family members. Although several hundred human and mouse KRAB-ZFPs have been identified or predicted, the biological functions of most KRAB-ZFP family members have gone unexplored. Furthermore, the evolutionary forces driving the extraordinary KRAB-ZFP expansion and diversification have remained mysterious for decades. In this review, we highlight recent studies that associate KRAB-ZFPs with the repression of parasitic DNA elements in the mammalian germ line and discuss the hypothesis that the KRAB-ZFP family primarily evolved as an adaptive genomic surveillance system against foreign DNA. Finally, we comment on the computational, genetic, and biochemical challenges of studying KRAB-ZFPs and attempt to predict how these challenges may be soon overcome.
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Affiliation(s)
- Gernot Wolf
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, MD 20892 USA
| | - David Greenberg
- The Gladstone Institute of Virology and Immunology, University of California, San Francisco, CA 94158 USA ; Present address: Pacific Biosciences, 1380 Willow Road, Menlo Park, CA 94025 USA
| | - Todd S Macfarlan
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, MD 20892 USA
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28
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Ichida Y, Utsunomiya Y, Yasuda T, Nakabayashi K, Sato T, Onodera M. Functional Domains of ZFP809 Essential for Nuclear Localization and Gene Silencing. PLoS One 2015; 10:e0139274. [PMID: 26417948 PMCID: PMC4587795 DOI: 10.1371/journal.pone.0139274] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 09/09/2015] [Indexed: 12/02/2022] Open
Abstract
Zinc finger protein 809 (ZFP809) is a member of the Kruppel-associated box-containing zinc finger protein (KRAB-ZFP) family, and is highly expressed in mouse immature cells. ZFP809 is known to inhibit the expression of transduced genes driven by Moloney murine leukemia virus (MoMLV)-typed retroviral vectors by binding to the primer binding site (PBS) located downstream of the MLV-long terminal repeat (LTR) of the vectors and recruiting protein complexes that introduce epigenetic silencing marks such as histone modifications and DNA methylation at the MLV-LTR. However, it remains undetermined what domains of ZFP809 among the KRAB domain at N-terminus and the seven zinc fingers are critical for gene silencing. In this study, we assessed subcellular localization, gene silencing ability, and binding ability to the PBS of a series of truncated and mutated ZFP809 proteins. We revealed the essential role of the KRAB A box for all functions assessed, together with the accessory roles of a subset of zinc fingers. Our data also suggest that interaction between KAP1 and the KRAB A box of ZFP809 is critical in KAP1-dependent control of gene silencing for ZFP809 targets.
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Affiliation(s)
- Yu Ichida
- Department of Human Genetics, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo, 157-8535, Japan
| | - Yuko Utsunomiya
- Department of Human Genetics, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo, 157-8535, Japan
| | - Toru Yasuda
- Department of Human Genetics, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo, 157-8535, Japan
| | - Kazuhiko Nakabayashi
- Department of Maternal-Fetal Biology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo, 157-8535, Japan
| | - Toshinori Sato
- Department of Biosciences and Informatics, Keio University, Yokohama, Kanagawa, 223-8522, Japan
| | - Masafumi Onodera
- Department of Human Genetics, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo, 157-8535, Japan
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29
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Friedli M, Trono D. The developmental control of transposable elements and the evolution of higher species. Annu Rev Cell Dev Biol 2015; 31:429-51. [PMID: 26393776 DOI: 10.1146/annurev-cellbio-100814-125514] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Transposable elements (TEs) account for at least 50% of the human genome. They constitute essential motors of evolution through their ability to modify genomic architecture, mutate genes and regulate gene expression. Accordingly, TEs are subject to tight epigenetic control during the earliest phases of embryonic development via histone and DNA methylation. Key to this process is recognition by sequence-specific RNA- and protein-based repressors. Collectively, these mediators are responsible for silencing a very broad range of TEs in an evolutionarily dynamic fashion. As a consequence, mobile elements and their controllers exert a marked influence on transcriptional networks in embryonic stem cells and a variety of adult tissues. The emerging picture is not that of a simple arms race but rather of a massive and sophisticated enterprise of TE domestication for the evolutionary benefit of the host.
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Affiliation(s)
- Marc Friedli
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland; ,
| | - Didier Trono
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland; ,
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30
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Jin S, Choi H, Kwon JT, Kim J, Jeong J, Kim J, Ham S, Cho BN, Yoo YJ, Cho C. Identification and characterization of reproductive KRAB-ZF genes in mice. Gene 2015; 565:45-55. [DOI: 10.1016/j.gene.2015.03.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 03/03/2015] [Accepted: 03/27/2015] [Indexed: 11/30/2022]
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31
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Robbez-Masson L, Rowe HM. Retrotransposons shape species-specific embryonic stem cell gene expression. Retrovirology 2015; 12:45. [PMID: 26021318 PMCID: PMC4448215 DOI: 10.1186/s12977-015-0173-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 05/07/2015] [Indexed: 01/20/2023] Open
Abstract
Over half of our genome is composed of retrotransposons, which are mobile elements that can readily amplify their copy number by replicating through an RNA intermediate. Most of these elements are no longer mobile but still contain regulatory sequences that can serve as promoters, enhancers or repressors for cellular genes. Despite dominating our genetic content, little is known about the precise functions of retrotransposons, which include both endogenous retroviruses (ERVs) and non-LTR elements like long interspersed nuclear element 1 (LINE-1). However, a few recent cutting-edge publications have illustrated how retrotransposons shape species-specific stem cell gene expression by two opposing mechanisms, involving their recruitment of stem cell-enriched transcription factors (TFs): firstly, they can activate expression of genes linked to naïve pluripotency, and secondly, they can induce repression of proximal genes. The paradox that different retrotransposons are active or silent in embryonic stem cells (ESCs) can be explained by differences between retrotransposon families, between individual copies within the same family, and between subpopulations of ESCs. Since they have coevolved with their host genomes, some of them have been co-opted to perform species-specific beneficial functions, while others have been implicated in genetic disease. In this review, we will discuss retrotransposon functions in ESCs, focusing on recent mechanistic advances of how HERV-H has been adopted to preserve human naïve pluripotency and how particular LINE-1, SVA and ERV family members recruit species-specific transcriptional repressors. This review highlights the fine balance between activation and repression of retrotransposons that exists to harness their ability to drive evolution, while minimizing the risk they pose to genome integrity.
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Affiliation(s)
- Luisa Robbez-Masson
- Division of Infection and Immunity, Medical Research Council Centre for Medical Molecular Virology, University College London, 90 Gower Street, London, WC1E 6BT, UK.
| | - Helen M Rowe
- Division of Infection and Immunity, Medical Research Council Centre for Medical Molecular Virology, University College London, 90 Gower Street, London, WC1E 6BT, UK.
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Xu X, Tan X, Tampe B, Nyamsuren G, Liu X, Maier LS, Sossalla S, Kalluri R, Zeisberg M, Hasenfuss G, Zeisberg EM. Epigenetic balance of aberrant Rasal1 promoter methylation and hydroxymethylation regulates cardiac fibrosis. Cardiovasc Res 2015; 105:279-91. [PMID: 25616414 DOI: 10.1093/cvr/cvv015] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
AIMS Methylation of CpG island promoters is a prototypical epigenetic mechanism to stably control gene expression. The aim of this study was to elucidate the contribution of aberrant promoter DNA methylation in pathological endothelial to mesenchymal transition (EndMT) and subsequent cardiac fibrosis. METHODS AND RESULTS In human coronary endothelial cells, TGFβ1 causes aberrant methylation of RASAL1 promoter, increased Ras-GTP activity, and EndMT. In end-stage failing vs. non-failing human myocardium, increased fibrosis was associated with significantly increased RASAL1 promoter methylation, decreased RASAL1 expression, increased Ras-GTP activity, and increased expression of markers of EndMT. In mice with pressure overload due to ascending aortic constriction, BMP7 significantly reduced RASAL1 promoter methylation, increased RASAL1 expression, and decreased EndMT markers as well as decreased cardiac fibrosis. The ten eleven translocation (TET) family enzyme TET3, which demethylates through hydroxymethylation, was significantly decreased in fibrotic mouse hearts, restored with BMP7, and BMP7 effects were absent in coronary endothelial cells with siRNA knockdown of TET3. CONCLUSION Our study provides proof-in-principle evidence that transcriptional suppression of RASAL1 through aberrant promoter methylation contributes to EndMT and ultimately to progression of cardiac fibrosis. Such aberrant methylation can be reversed through Tet3-mediated hydroxymethylation, which can be specifically induced by BMP7. This may reflect a new treatment strategy to stop cardiac fibrosis.
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Affiliation(s)
- Xingbo Xu
- Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Xiaoying Tan
- Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Björn Tampe
- Department of Nephrology and Rheumatology, University Medical Center of Göttingen, Georg-August University, Göttingen, Germany
| | - Gunsmaa Nyamsuren
- Department of Nephrology and Rheumatology, University Medical Center of Göttingen, Georg-August University, Göttingen, Germany
| | - Xiaopeng Liu
- Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University of Regensburg, Regensburg, Germany
| | - Samuel Sossalla
- Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Raghu Kalluri
- Department of Cancer Biology and the Metastasis Research Center, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Michael Zeisberg
- Department of Nephrology and Rheumatology, University Medical Center of Göttingen, Georg-August University, Göttingen, Germany
| | - Gerd Hasenfuss
- Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | - Elisabeth M Zeisberg
- Department of Cardiology and Pneumology, University Medical Center of Göttingen, Georg-August University, Robert-Koch-Str. 40, 37075 Göttingen, Germany German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
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Thompson PJ, Dulberg V, Moon KM, Foster LJ, Chen C, Karimi MM, Lorincz MC. hnRNP K coordinates transcriptional silencing by SETDB1 in embryonic stem cells. PLoS Genet 2015; 11:e1004933. [PMID: 25611934 PMCID: PMC4303303 DOI: 10.1371/journal.pgen.1004933] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 12/02/2014] [Indexed: 01/23/2023] Open
Abstract
Retrotransposition of endogenous retroviruses (ERVs) poses a substantial threat to genome stability. Transcriptional silencing of a subset of these parasitic elements in early mouse embryonic and germ cell development is dependent upon the lysine methyltransferase SETDB1, which deposits H3K9 trimethylation (H3K9me3) and the co-repressor KAP1, which binds SETDB1 when SUMOylated. Here we identified the transcription co-factor hnRNP K as a novel binding partner of the SETDB1/KAP1 complex in mouse embryonic stem cells (mESCs) and show that hnRNP K is required for ERV silencing. RNAi-mediated knockdown of hnRNP K led to depletion of H3K9me3 at ERVs, concomitant with de-repression of proviral reporter constructs and specific ERV subfamilies, as well as a cohort of germline-specific genes directly targeted by SETDB1. While hnRNP K recruitment to ERVs is dependent upon KAP1, SETDB1 binding at these elements requires hnRNP K. Furthermore, an intact SUMO conjugation pathway is necessary for SETDB1 recruitment to proviral chromatin and depletion of hnRNP K resulted in reduced SUMOylation at ERVs. Taken together, these findings reveal a novel regulatory hierarchy governing SETDB1 recruitment and in turn, transcriptional silencing in mESCs. Retroelements, including endogenous retroviruses (ERVs), pose a significant threat to genome stability. In mouse embryonic stem (ES) cells, the enzyme SETDB1 safeguards the genome against transcription of specific ERVs by depositing a repressive mark H3K9 trimethylation (H3K9me3). Although SETDB1 is recruited to ERVs by its binding partner KAP1, the molecular basis of this silencing pathway is not clear. Using biochemical and genetic approaches, we identified hnRNP K as a novel component of this silencing pathway that facilitates the recruitment of SETDB1 to ERVs to promote their repression. HnRNP K binds to ERV sequences via KAP1 and subsequently promotes SETDB1 binding. Together, our results reveal a novel function for hnRNP K in transcriptional silencing of ERVs and demonstrate a new regulatory mechanism governing the deposition of H3K9me3 by SETDB1 in ES cells.
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Affiliation(s)
- Peter J. Thompson
- Life Sciences Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Vered Dulberg
- Life Sciences Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kyung-Mee Moon
- Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Leonard J. Foster
- Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Carol Chen
- Life Sciences Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Mohammad M. Karimi
- Life Sciences Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- Biomedical Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Matthew C. Lorincz
- Life Sciences Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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Retroviral transcriptional regulation and embryonic stem cells: war and peace. Mol Cell Biol 2014; 35:770-7. [PMID: 25547290 DOI: 10.1128/mcb.01293-14] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Retroviruses have evolved complex transcriptional enhancers and promoters that allow their replication in a wide range of tissue and cell types. Embryonic stem (ES) cells, however, characteristically suppress transcription of proviruses formed after infection by exogenous retroviruses and also of most members of the vast array of endogenous retroviruses in the genome. These cells have unusual profiles of transcribed genes and are poised to make rapid changes in those profiles upon induction of differentiation. Many of the transcription factors in ES cells control both host and retroviral genes coordinately, such that retroviral expression patterns can serve as markers of ES cell pluripotency. This overlap is not coincidental; retrovirus-derived regulatory sequences are often used to control cellular genes important for pluripotency. These sequences specify the temporal control and perhaps "noisy" control of cellular genes that direct proper cell gene expression in primitive cells and their differentiating progeny. The evidence suggests that the viral elements have been domesticated for host needs, reflecting the wide-ranging exploitation of any and all available DNA sequences in assembling regulatory networks.
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Marchal C, Miotto B. Emerging Concept in DNA Methylation: Role of Transcription Factors in Shaping DNA Methylation Patterns. J Cell Physiol 2014; 230:743-51. [DOI: 10.1002/jcp.24836] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 10/01/2014] [Indexed: 02/04/2023]
Affiliation(s)
- Claire Marchal
- Université Paris Diderot; Sorbonne Paris Cité; Epigenetics and Cell Fate; Paris France
| | - Benoit Miotto
- Université Paris Diderot; Sorbonne Paris Cité; Epigenetics and Cell Fate; Paris France
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Cheng CT, Kuo CY, Ann DK. KAPtain in charge of multiple missions: Emerging roles of KAP1. World J Biol Chem 2014; 5:308-320. [PMID: 25225599 PMCID: PMC4160525 DOI: 10.4331/wjbc.v5.i3.308] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 03/21/2014] [Accepted: 06/20/2014] [Indexed: 02/05/2023] Open
Abstract
KAP1/TRIM28/TIF1β was identified nearly twenty years ago as a universal transcriptional co-repressor because it interacts with a large KRAB-containing zinc finger protein (KRAB-ZFP) transcription factor family. Many studies demonstrate that KAP1 affects gene expression by regulating the transcription of KRAB-ZFP-specific loci, trans-repressing as a transcriptional co-repressor or epigenetically modulating chromatin structure. Emerging evidence suggests that KAP1 also functions independent of gene regulation by serving as a SUMO/ubiquitin E3 ligase or signaling scaffold protein to mediate signal transduction. KAP1 is subjected to multiple post-translational modifications (PTMs), including serine/tyrosine phosphorylation, SUMOylation, and acetylation, which coordinately regulate KAP1 function and its protein abundance. KAP1 is involved in multiple aspects of cellular activities, including DNA damage response, virus replication, cytokine production and stem cell pluripotency. Moreover, knockout of KAP1 results in embryonic lethality, indicating that KAP1 is crucial for embryonic development and possibly impacts a wide-range of (patho)physiological manifestations. Indeed, studies from conditional knockout mouse models reveal that KAP1-deficiency significantly impairs vital physiological processes, such as immune maturation, stress vulnerability, hepatic metabolism, gamete development and erythropoiesis. In this review, we summarize and evaluate current literatures involving the biochemical and physiological functions of KAP1. In addition, increasing studies on the clinical relevance of KAP1 in cancer will also be discussed.
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Castro-Diaz N, Ecco G, Coluccio A, Kapopoulou A, Yazdanpanah B, Friedli M, Duc J, Jang SM, Turelli P, Trono D. Evolutionally dynamic L1 regulation in embryonic stem cells. Genes Dev 2014; 28:1397-409. [PMID: 24939876 PMCID: PMC4083085 DOI: 10.1101/gad.241661.114] [Citation(s) in RCA: 152] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Mobile elements are important evolutionary forces that challenge genomic integrity. Long interspersed element-1 (L1, also known as LINE-1) is the only autonomous transposon still active in the human genome. It displays an unusual pattern of evolution, with, at any given time, a single active L1 lineage amplifying to thousands of copies before getting replaced by a new lineage, likely under pressure of host restriction factors, which act notably by silencing L1 expression during early embryogenesis. Here, we demonstrate that in human embryonic stem (hES) cells, KAP1 (KRAB [Krüppel-associated box domain]-associated protein 1), the master cofactor of KRAB-containing zinc finger proteins (KRAB-ZFPs) previously implicated in the restriction of endogenous retroviruses, represses a discrete subset of L1 lineages predicted to have entered the ancestral genome between 26.8 million and 7.6 million years ago. In mice, we documented a similar chronologically conditioned pattern, albeit with a much contracted time scale. We could further identify an L1-binding KRAB-ZFP, suggesting that this rapidly evolving protein family is more globally responsible for L1 recognition. KAP1 knockdown in hES cells induced the expression of KAP1-bound L1 elements, but their younger, human-specific counterparts (L1Hs) were unaffected. Instead, they were stimulated by depleting DNA methyltransferases, consistent with recent evidence demonstrating that the PIWI-piRNA (PIWI-interacting RNA) pathway regulates L1Hs in hES cells. Altogether, these data indicate that the early embryonic control of L1 is an evolutionarily dynamic process and support a model in which newly emerged lineages are first suppressed by DNA methylation-inducing small RNA-based mechanisms before KAP1-recruiting protein repressors are selected.
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Affiliation(s)
- Nathaly Castro-Diaz
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Gabriela Ecco
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Andrea Coluccio
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Adamandia Kapopoulou
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Benyamin Yazdanpanah
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Marc Friedli
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Julien Duc
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Suk Min Jang
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Priscilla Turelli
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Didier Trono
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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Abstract
The ability of adaptive immune system to protect higher vertebrates from pathogens resides in the ability of B and T cells to express different antigen specific receptors and to respond to different threats by activating distinct differentiation and/or activation pathways. In the past 10 years, the major role of epigenetics in controlling molecular mechanisms responsible for these peculiar features and, more in general, for lymphocyte development has become evident. KRAB-ZFPs is the widest family of mammalian transcriptional repressors, which function through the recruitment of the co-factor KRAB-Associated Protein 1 (KAP1) that in turn engages histone modifiers inducing heterochromatin formation. Although most of the studies on KRAB proteins have been performed in embryonic cells, more recent reports highlighted a relevant role for these proteins also in adult tissues. This article will review the role of KRAB-ZFP and KAP1 in the epigenetic control of mouse and human adaptive immune cells.
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The B-subdomain of the Xenopus laevis XFIN KRAB-AB domain is responsible for its weaker transcriptional repressor activity compared to human ZNF10/Kox1. PLoS One 2014; 9:e87609. [PMID: 24498343 PMCID: PMC3912051 DOI: 10.1371/journal.pone.0087609] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 12/23/2013] [Indexed: 12/12/2022] Open
Abstract
The Krüppel-associated box (KRAB) domain interacts with the nuclear hub protein TRIM28 to initiate or mediate chromatin-dependent processes like transcriptional repression, imprinting or suppression of endogenous retroviruses. The prototype KRAB domain initially identified in ZNF10/KOX1 encompasses two subdomains A and B that are found in hundreds of zinc finger transcription factors studied in human and murine genomes. Here we demonstrate for the first time transcriptional repressor activity of an amphibian KRAB domain. After sequence correction, the updated KRAB-AB domain of zinc finger protein XFIN from the frog Xenopus laevis was found to confer transcriptional repression in reporter assays in Xenopus laevis A6 kidney cells as well as in human HeLa, but not in the minnow Pimephales promelas fish cell line EPC. Binding of the XFIN KRAB-AB domain to human TRIM28 was demonstrated in a classical co-immunoprecipitation approach and visualized in a single-cell compartmentalization assay. XFIN-AB displayed reduced potency in repression as well as lower strength of interaction with TRIM28 compared to ZNF10 KRAB-AB. KRAB-B subdomain swapping between the two KRAB domains indicated that it was mainly the KRAB-B subdomain of XFIN that was responsible for its lower capacity in repression and binding to human TRIM28. In EPC fish cells, ZNF10 and XFIN KRAB repressor activity could be partially restored to low levels by adding exogenous human TRIM28. In contrast to XFIN, we did not find any transcriptional repression activity for the KRAB-like domain of human PRDM9 in HeLa cells. PRDM9 is thought to harbor an evolutionary older domain related to KRAB whose homologs even occur in invertebrates. Our results support the notion that functional bona fide KRAB domains which confer transcriptional repression and interact with TRIM28 most likely co-evolved together with TRIM28 at the beginning of tetrapode evolution.
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