101
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Gazquez-Gutierrez A, Witteveldt J, R Heras S, Macias S. Sensing of transposable elements by the antiviral innate immune system. RNA (NEW YORK, N.Y.) 2021; 27:rna.078721.121. [PMID: 33888553 PMCID: PMC8208052 DOI: 10.1261/rna.078721.121] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/17/2021] [Indexed: 05/15/2023]
Abstract
Around half of the genome in mammals is composed of transposable elements (TEs) such as DNA transposons and retrotransposons. Several mechanisms have evolved to prevent their activity and the detrimental impact of their insertional mutagenesis. Despite these potentially negative effects, TEs are essential drivers of evolution, and in certain settings, beneficial to their hosts. For instance, TEs have rewired the antiviral gene regulatory network and are required for early embryonic development. However, due to structural similarities between TE-derived and viral nucleic acids, cells can misidentify TEs as invading viruses and trigger the major antiviral innate immune pathway, the type I interferon (IFN) response. This review will focus on the different settings in which the role of TE-mediated IFN activation has been documented, including cancer and senescence. Importantly, TEs may also play a causative role in the development of complex autoimmune diseases characterised by constitutive type I IFN activation. All these observations suggest the presence of strong but opposing forces driving the coevolution of TEs and antiviral defence. A better biological understanding of the TE replicative cycle as well as of the antiviral nucleic acid sensing mechanisms will provide insights into how these two biological processes interact and will help to design better strategies to treat human diseases characterised by aberrant TE expression and/or type I IFN activation.
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Affiliation(s)
| | - Jeroen Witteveldt
- University of Edinburgh - Institute of Immunology and Infection Research
| | - Sara R Heras
- GENYO. Centre for Genomics and Oncological Research, Pfizer University of Granada
| | - Sara Macias
- Institute of Immunology and Infection Research
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102
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Kristensen MK, Christensen T. Regulation of the expression of human endogenous retroviruses: elements in fetal development and a possible role in the development of cancer and neurological diseases. APMIS 2021; 129:241-253. [PMID: 33683784 DOI: 10.1111/apm.13130] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 03/03/2021] [Indexed: 12/14/2022]
Abstract
Human endogenous retroviruses (HERVs) are remnants of ancient retroviral germline infections. Most HERV sequences are silenced in somatic cells, but interest is emerging on the involvement of HERV derived transcripts and proteins in human physiology and disease. A HERV-W encoded protein, syncytin-1, has been co-opted into fetal physiology, where it plays a role in trophoblast formation. Altered HERV transcription and expression of HERV derived proteins are associated with various cancer types and neurological diseases such as multiple sclerosis (MS). The implication of HERVs as potential mediators of both health and disease suggests important roles of regulatory mechanisms and alterations of these in physiological and pathological processes. The regulation of HERV sequences is mediated by a wide variety of mechanisms, and the focus of this review is on selected aspects of these, including epigenetic mechanisms such as CpG methylation and histone modifications of the HP1-H3K9me axis, viral transactivation events, and regulatory perspectives of transient stimuli in the microenvironment. Increasing knowledge of the regulation of HERV sequences will not only contribute to the understanding of complex pathogeneses, but also may pinpoint potential targets for better diagnosis and treatment in complex diseases as MS.
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103
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Glinsky GV. Genomics-Guided Drawing of Molecular and Pathophysiological Components of Malignant Regulatory Signatures Reveals a Pivotal Role in Human Diseases of Stem Cell-Associated Retroviral Sequences and Functionally-Active hESC Enhancers. Front Oncol 2021; 11:638363. [PMID: 33869024 PMCID: PMC8044830 DOI: 10.3389/fonc.2021.638363] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 03/10/2021] [Indexed: 12/31/2022] Open
Abstract
Repetitive DNA sequences (repeats) colonized two-third of human genome and a majority of repeats comprised of transposable genetic elements (TE). Evolutionary distinct categories of TE represent nucleic acid sequences that are repeatedly copied from and pasted into chromosomes at multiple genomic locations and acquired a multitude of regulatory functions. Here, genomics-guided maps of stemness regulatory signatures were drawn to dissect the contribution of TE to clinical manifestations of malignant phenotypes of human cancers. From patients’ and physicians’ perspectives, the clinical definition of a tumor’s malignant phenotype could be restricted to the early diagnosis of sub-types of malignancies with the increased risk of existing therapy failure and high likelihood of death from cancer. It is the viewpoint from which the understanding of stemness and malignant regulatory signatures is considered in this contribution. Genomics-guided analyses of experimental and clinical observations revealed the pivotal role of human stem cell-associated retroviral sequences (SCARS) in the origin and pathophysiology of clinically-lethal malignancies. SCARS were defined as the evolutionary- and biologically-related family of genomic regulatory sequences, the principal physiological function of which is to create and maintain the stemness phenotype during human preimplantation embryogenesis. For cell differentiation to occur, SCARS expression must be silenced and SCARS activity remains repressed in most terminally-differentiated human cells which are destined to perform specialized functions in the human body. Epigenetic reprogramming, de-repression, and sustained activity of SCARS results in various differentiation-defective phenotypes. One of the most prominent tissue- and organ-specific clinical manifestations of sustained SCARS activities is diagnosed as a pathological condition defined by a consensus of morphological, molecular, and genetic examinations as the malignant growth. Here, contemporary evidence are acquired, analyzed, and reported defining both novel diagnostic tools and druggable molecular targets readily amenable for diagnosis and efficient therapeutic management of clinically-lethal malignancies. These diagnostic and therapeutic approaches are based on monitoring of high-fidelity molecular signals of continuing SCARS activities in conjunction with genomic regulatory networks of thousands’ functionally-active embryonic enhancers affecting down-stream phenotype-altering genetic loci. Collectively, reported herein observations support a model of SCARS-activation triggered singular source code facilitating the intracellular propagation and intercellular (systemic) dissemination of disease states in the human body.
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Affiliation(s)
- Gennadi V Glinsky
- Institute of Engineering in Medicine, University of California, San Diego, CA, United States.,Department of Functional & Translational Genomics, OncoSCAR, Inc., Portland, OR, United States
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104
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He J, Babarinde IA, Sun L, Xu S, Chen R, Shi J, Wei Y, Li Y, Ma G, Zhuang Q, Hutchins AP, Chen J. Identifying transposable element expression dynamics and heterogeneity during development at the single-cell level with a processing pipeline scTE. Nat Commun 2021; 12:1456. [PMID: 33674594 PMCID: PMC7935913 DOI: 10.1038/s41467-021-21808-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 02/04/2021] [Indexed: 12/16/2022] Open
Abstract
Transposable elements (TEs) make up a majority of a typical eukaryote’s genome, and contribute to cell heterogeneity in unclear ways. Single-cell sequencing technologies are powerful tools to explore cells, however analysis is typically gene-centric and TE expression has not been addressed. Here, we develop a single-cell TE processing pipeline, scTE, and report the expression of TEs in single cells in a range of biological contexts. Specific TE types are expressed in subpopulations of embryonic stem cells and are dynamically regulated during pluripotency reprogramming, differentiation, and embryogenesis. Unexpectedly, TEs are expressed in somatic cells, including human disease-specific TEs that are undetectable in bulk analyses. Finally, we apply scTE to single-cell ATAC-seq data, and demonstrate that scTE can discriminate cell type using chromatin accessibly of TEs alone. Overall, our results classify the dynamic patterns of TEs in single cells and their contributions to cell heterogeneity. How transposable elements (TE) contribute to cell fate changes is unclear. Here, the authors generate a pipeline to quantify TE expression from single cell data. They show the dynamic expression of TEs from gastrulation to somatic cell reprogramming and human disease
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Affiliation(s)
- Jiangping He
- Center for Cell Lineage and Atlas (CCLA), Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Isaac A Babarinde
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Li Sun
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Shuyang Xu
- Key Laboratory of Regenerative Biology of the Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Ruhai Chen
- Key Laboratory of Regenerative Biology of the Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,Joint School of Life Sciences, Guangzhou Medical University and Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Junjie Shi
- Key Laboratory of Regenerative Biology of the Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Yuanjie Wei
- Center for Cell Lineage and Atlas (CCLA), Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Yuhao Li
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Gang Ma
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Qiang Zhuang
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Andrew P Hutchins
- Department of Biology, Southern University of Science and Technology, Shenzhen, China.
| | - Jiekai Chen
- Center for Cell Lineage and Atlas (CCLA), Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China. .,Key Laboratory of Regenerative Biology of the Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China. .,Joint School of Life Sciences, Guangzhou Medical University and Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.
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105
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The Regulation and Functions of Endogenous Retrovirus in Embryo Development and Stem Cell Differentiation. Stem Cells Int 2021; 2021:6660936. [PMID: 33727936 PMCID: PMC7937486 DOI: 10.1155/2021/6660936] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 02/19/2021] [Indexed: 11/17/2022] Open
Abstract
Endogenous retroviruses (ERVs) are repetitive sequences in the genome, belonging to the retrotransposon family. During the course of life, ERVs are associated with multiple aspects of chromatin and transcriptional regulation in development and pathological conditions. In mammalian embryos, ERVs are extensively activated in early embryo development, but with a highly restricted spatial-temporal pattern; and they are drastically silenced during differentiation with exceptions in extraembryonic tissue and germlines. The dynamic activation pattern of ERVs raises questions about how ERVs are regulated in the life cycle and whether they are functionally important to cell fate decision during early embryo and somatic cell development. Therefore, in this review, we focus on the pieces of evidence demonstrating regulations and functions of ERVs during stem cell differentiation, which suggests that ERV activation is not a passive result of cell fate transition but the active epigenetic and transcriptional regulation during mammalian development and stem cell differentiation.
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106
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Sun L, Fu X, Ma G, Hutchins AP. Chromatin and Epigenetic Rearrangements in Embryonic Stem Cell Fate Transitions. Front Cell Dev Biol 2021; 9:637309. [PMID: 33681220 PMCID: PMC7930395 DOI: 10.3389/fcell.2021.637309] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 01/19/2021] [Indexed: 12/13/2022] Open
Abstract
A major event in embryonic development is the rearrangement of epigenetic information as the somatic genome is reprogrammed for a new round of organismal development. Epigenetic data are held in chemical modifications on DNA and histones, and there are dramatic and dynamic changes in these marks during embryogenesis. However, the mechanisms behind this intricate process and how it is regulating and responding to embryonic development remain unclear. As embryos develop from totipotency to pluripotency, they pass through several distinct stages that can be captured permanently or transiently in vitro. Pluripotent naïve cells resemble the early epiblast, primed cells resemble the late epiblast, and blastomere-like cells have been isolated, although fully totipotent cells remain elusive. Experiments using these in vitro model systems have led to insights into chromatin changes in embryonic development, which has informed exploration of pre-implantation embryos. Intriguingly, human and mouse cells rely on different signaling and epigenetic pathways, and it remains a mystery why this variation exists. In this review, we will summarize the chromatin rearrangements in early embryonic development, drawing from genomic data from in vitro cell lines, and human and mouse embryos.
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Affiliation(s)
| | | | | | - Andrew P. Hutchins
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
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107
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Semi K, Takashima Y. Pluripotent stem cells for the study of early human embryology. Dev Growth Differ 2021; 63:104-115. [PMID: 33570781 PMCID: PMC8251740 DOI: 10.1111/dgd.12715] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 02/02/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023]
Abstract
Forty years have passed since the first pluripotent stem cells (PSCs), mouse embryonic stem cells (ESCs), were established. Since then, several PSCs have been reported, including human ESCs in 1998, mouse epiblast stem cells (EpiSCs) in 2007, induced PSCs (iPSCs) in 2006 and 2007, and naïve human PSCs in 2014. Naïve PSCs are thought to correspond to pre-implantation epiblast cells, whereas conventional (or primed) human PSCs correspond to post-implantation epiblast cells. Thus, naïve and primed PSCs are classified by their developmental stages and have stage-specific characteristics, despite sharing the common feature of pluripotency. In this review, we discuss the current status of PSCs and their use to model human peri-implantation development.
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Affiliation(s)
- Katsunori Semi
- Center for iPS Cell Research and ApplicationKyoto UniversityKyotoJapan
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108
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Nsd2 Represses Endogenous Retrovirus MERVL in Embryonic Stem Cells. Stem Cells Int 2021; 2021:6663960. [PMID: 33531910 PMCID: PMC7834818 DOI: 10.1155/2021/6663960] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/31/2020] [Accepted: 01/05/2021] [Indexed: 11/17/2022] Open
Abstract
The facilitates chromatin transcription (FACT) complex is a histone H2A/H2B chaperone, which represses endogenous retroviruses (ERVs) and transcription of ERV-chimeric transcripts. It binds to both transcription start site and gene body region. Here, we investigated the downstream targets of FACT complex to identify the potential regulators of MERVL, which is a key 2-cell marker gene. H3K36me2 profile was positively correlated with that of FACT component Ssrp1. Among H3K36me2 deposition enzymes, Nsd2 was downregulated after the loss of Ssrp1. Furthermore, we demonstrated that Nsd2 repressed the expression of ERVs without affecting the expression of pluripotency genes. The expression of MERVL and 2-cell genes was partially rescued by Nsd2 overexpression. The enrichment of H3K36me2 decreased on MERVL-chimeric gene in ESCs without Ssrp1. Our study discovers that Nsd2 is a repressor of MERVL, and FACT partially represses MERVL expression by regulating the expression of Nsd2 and its downstream H3K36me2.
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109
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Natoli M, Gallon J, Lu H, Amgheib A, Pinato DJ, Mauri FA, Marafioti T, Akarca AU, Ullmo I, Ip J, Aboagye EO, Brown R, Karadimitris A, Ghaem-Maghami S. Transcriptional analysis of multiple ovarian cancer cohorts reveals prognostic and immunomodulatory consequences of ERV expression. J Immunother Cancer 2021; 9:jitc-2020-001519. [PMID: 33436485 PMCID: PMC7805370 DOI: 10.1136/jitc-2020-001519] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Endogenous retroviruses (ERVs) play a role in a variety of biological processes, including embryogenesis and cancer. DNA methyltransferase inhibitors (DNMTi)-induced ERV expression triggers interferon responses in ovarian cancer cells via the viral sensing machinery. Baseline expression of ERVs also occurs in cancer cells, though this process is poorly understood and previously unexplored in epithelial ovarian cancer (EOC). Here, the prognostic and immunomodulatory consequences of baseline ERV expression was assessed in EOC. METHODS ERV expression was assessed using EOC transcriptional data from The Cancer Genome Atlas (TCGA) and from an independent cohort (Hammersmith Hospital, HH), as well as from untreated or DNMTi-treated EOC cell lines. Least absolute shrinkage and selection operator (LASSO) logistic regression defined an ERV expression score to predict patient prognosis. Immunohistochemistry (IHC) was conducted on the HH cohort. Combination of DNMTi treatment with γδ T cells was tested in vitro, using EOC cell lines and patient-derived tumor cells. RESULTS ERV expression was found to define clinically relevant subsets of EOC patients. An ERV prognostic score was successfully generated in TCGA and validated in the independent cohort. In EOC patients from this cohort, a high ERV score was associated with better survival (log-rank p=0.0009) and correlated with infiltration of CD8+PD1+T cells (r=0.46, p=0.0001). In the TCGA dataset, a higher ERV score was found in BRCA1/2 mutant tumors, compared to wild type (p=0.015), while a lower ERV score was found in CCNE1 amplified tumors, compared to wild type (p=0.019). In vitro, baseline ERV expression dictates the level of ERV induction in response to DNMTi. Manipulation of an ERV expression threshold by DNMTi resulted in improved EOC cell killing by cytotoxic immune cells. CONCLUSIONS These findings uncover the potential for baseline ERV expression to robustly inform EOC patient prognosis, influence tumor immune infiltration and affect antitumor immunity.
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Affiliation(s)
- Marina Natoli
- Department of Surgery and Cancer, Imperial College London, London, UK.,Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - John Gallon
- Department of Surgery and Cancer, Imperial College London, London, UK.,Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Haonan Lu
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Ala Amgheib
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - David J Pinato
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Francesco A Mauri
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Teresa Marafioti
- Department of Pathology, University College London Cancer Institute, London, UK
| | - Ayse U Akarca
- Department of Pathology, University College London Cancer Institute, London, UK
| | - Ines Ullmo
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Jacey Ip
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Eric O Aboagye
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Robert Brown
- Department of Surgery and Cancer, Imperial College London, London, UK.,Department of Pathology, Institute of Cancer Research, London, UK
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110
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Shao W, Wang T. Transcript assembly improves expression quantification of transposable elements in single-cell RNA-seq data. Genome Res 2021; 31:88-100. [PMID: 33355230 PMCID: PMC7849386 DOI: 10.1101/gr.265173.120] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 11/24/2020] [Indexed: 12/28/2022]
Abstract
Transposable elements (TEs) are an integral part of the host transcriptome. TE-containing noncoding RNAs (ncRNAs) show considerable tissue specificity and play important roles during development, including stem cell maintenance and cell differentiation. Recent advances in single-cell RNA-seq (scRNA-seq) revolutionized cell type-specific gene expression analysis. However, effective scRNA-seq quantification tools tailored for TEs are lacking, limiting our ability to dissect TE expression dynamics at single-cell resolution. To address this issue, we established a TE expression quantification pipeline that is compatible with scRNA-seq data generated across multiple technology platforms. We constructed TE-containing ncRNA references using bulk RNA-seq data and showed that quantifying TE expression at the transcript level effectively reduces noise. As proof of principle, we applied this strategy to mouse embryonic stem cells and successfully captured the expression profile of endogenous retroviruses in single cells. We further expanded our analysis to scRNA-seq data from early stages of mouse embryogenesis. Our results illustrated the dynamic TE expression at preimplantation stages and revealed 146 TE-containing ncRNA transcripts with substantial tissue specificity during gastrulation and early organogenesis.
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Affiliation(s)
- Wanqing Shao
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
- Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Ting Wang
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
- Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, Missouri 63108, USA
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111
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Evans TA, Erwin JA. Retroelement-derived RNA and its role in the brain. Semin Cell Dev Biol 2020; 114:68-80. [PMID: 33229216 DOI: 10.1016/j.semcdb.2020.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 10/20/2020] [Accepted: 11/04/2020] [Indexed: 12/17/2022]
Abstract
Comprising ~40% of the human genome, retroelements are mobile genetic elements which are transcribed into RNA, then reverse-transcribed into DNA and inserted into a new site in the genome. Retroelements are referred to as "genetic parasites", residing among host genes and relying on host machinery for transcription and evolutionary propagation. The healthy brain has the highest expression of retroelement-derived sequences compared to other somatic tissue, which leads to the question: how does retroelement-derived RNA influence human traits and cellular states? While the functional importance of upregulating retroelement expression in the brain is an active area of research, RNA species derived from retroelements influence both self- and host gene expression by contributing to chromatin remodeling, alternative splicing, somatic mosaicism and translational repression. Here, we review the emerging evidence that the functional importance of RNA derived from retroelements is multifaceted. Retroelements can influence organismal states through the seeding of epigenetic states in chromatin, the production of structured RNA and even catalytically active ribozymes, the generation of cytoplasmic ssDNA and RNA/DNA hybrids, the production of viral-like proteins, and the generation of somatic mutations. Comparative sequencing suggests that retroelements can contribute to intraspecies variation through these mechanisms to alter transcript identity and abundance. In humans, an increasing number of neurodevelopmental and neurodegenerative conditions are associated with dysregulated retroelements, including Aicardi-Goutieres syndrome (AGS), Rett syndrome (RTT), Amyotrophic Lateral Sclerosis (ALS), Alzheimer's disease (AD), multiple sclerosis (MS), schizophrenia (SZ), and aging. Taken together, these concepts suggest a larger functional role for RNA derived from retroelements. This review aims to define retroelement-derived RNA, discuss how it impacts the mammalian genome, as well as summarize data supporting phenotypic consequences of this unique RNA subset in the brain.
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Affiliation(s)
- Taylor A Evans
- Lieber Institute for Brain Development, Baltimore, MD, USA; Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Jennifer Ann Erwin
- Lieber Institute for Brain Development, Baltimore, MD, USA; Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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112
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Hwang YS, Suzuki S, Seita Y, Ito J, Sakata Y, Aso H, Sato K, Hermann BP, Sasaki K. Reconstitution of prospermatogonial specification in vitro from human induced pluripotent stem cells. Nat Commun 2020; 11:5656. [PMID: 33168808 PMCID: PMC7653920 DOI: 10.1038/s41467-020-19350-3] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 10/09/2020] [Indexed: 12/13/2022] Open
Abstract
Establishment of spermatogonia throughout the fetal and postnatal period is essential for production of spermatozoa and male fertility. Here, we establish a protocol for in vitro reconstitution of human prospermatogonial specification whereby human primordial germ cell (PGC)-like cells differentiated from human induced pluripotent stem cells are further induced into M-prospermatogonia-like cells and T1 prospermatogonia-like cells (T1LCs) using long-term cultured xenogeneic reconstituted testes. Single cell RNA-sequencing is used to delineate the lineage trajectory leading to T1LCs, which closely resemble human T1-prospermatogonia in vivo and exhibit gene expression related to spermatogenesis and diminished proliferation, a hallmark of quiescent T1 prospermatogonia. Notably, this system enables us to visualize the dynamic and stage-specific regulation of transposable elements during human prospermatogonial specification. Together, our findings pave the way for understanding and reconstructing human male germline development in vitro. Spermatogonia establishment in the fetal and postnatal period is essential for spermatozoa production. Here the authors present a protocol for in vitro reconstitution of human prospermatogonial specification and perform single cell RNA-sequencing to delineate lineage trajectories.
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Affiliation(s)
- Young Sun Hwang
- Institute for Regenerative Medicine, Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Shinnosuke Suzuki
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Yasunari Seita
- Institute for Regenerative Medicine, Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA.,Bell Research Center for Reproductive Health and Cancer, Nagoya, Aichi, Japan
| | - Jumpei Ito
- Division of Systems Virology, Department of infectious Disease Control, International Research Center for infectious Diseases, Institute of Medical Science, The University of Tokyo, Tokyo, 1088639, Japan
| | - Yuka Sakata
- Institute for Regenerative Medicine, Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Hirofumi Aso
- Division of Systems Virology, Department of infectious Disease Control, International Research Center for infectious Diseases, Institute of Medical Science, The University of Tokyo, Tokyo, 1088639, Japan
| | - Kei Sato
- Division of Systems Virology, Department of infectious Disease Control, International Research Center for infectious Diseases, Institute of Medical Science, The University of Tokyo, Tokyo, 1088639, Japan
| | - Brian P Hermann
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Kotaro Sasaki
- Institute for Regenerative Medicine, Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA.
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113
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Min B, Park JS, Jeong YS, Jeon K, Kang YK. Dnmt1 binds and represses genomic retroelements via DNA methylation in mouse early embryos. Nucleic Acids Res 2020; 48:8431-8444. [PMID: 32667642 PMCID: PMC7470951 DOI: 10.1093/nar/gkaa584] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 06/10/2020] [Accepted: 07/03/2020] [Indexed: 12/12/2022] Open
Abstract
Genome-wide passive DNA demethylation in cleavage-stage mouse embryos is related to the cytoplasmic localization of the maintenance methyltransferase DNMT1. However, recent studies provided evidences of the nuclear localization of DNMT1 and its contribution to the maintenance of methylation levels of imprinted regions and other genomic loci in early embryos. Using the DNA adenine methylase identification method, we identified Dnmt1-binding regions in four- and eight-cell embryos. The unbiased distribution of Dnmt1 peaks in the genic regions (promoters and CpG islands) as well as the absence of a correlation between the Dnmt1 peaks and the expression levels of the peak-associated genes refutes the active participation of Dnmt1 in the transcriptional regulation of genes in the early developmental period. Instead, Dnmt1 was found to associate with genomic retroelements in a greatly biased fashion, particularly with the LINE1 (long interspersed nuclear elements) and ERVK (endogenous retrovirus type K) sequences. Transcriptomic analysis revealed that the transcripts of the Dnmt1-enriched retroelements were overrepresented in Dnmt1 knockdown embryos. Finally, methyl-CpG-binding domain sequencing proved that the Dnmt1-enriched retroelements, which were densely methylated in wild-type embryos, became demethylated in the Dnmt1-depleted embryos. Our results indicate that Dnmt1 is involved in the repression of retroelements through DNA methylation in early mouse development.
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Affiliation(s)
- Byungkuk Min
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Jung Sun Park
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Young Sun Jeong
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Kyuheum Jeon
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea.,Department of Functional Genomics, Korea University of Science and Technology, Daejeon 34113, South Korea
| | - Yong-Kook Kang
- Development and Differentiation Research Center, Korea Research Institute of Bioscience Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, South Korea.,Department of Functional Genomics, Korea University of Science and Technology, Daejeon 34113, South Korea
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114
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Chen F, Zhang W, Xie D, Gao T, Dong Z, Lu X. Histone chaperone FACT represses retrotransposon MERVL and MERVL-derived cryptic promoters. Nucleic Acids Res 2020; 48:10211-10225. [PMID: 32894293 PMCID: PMC7544220 DOI: 10.1093/nar/gkaa732] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 08/19/2020] [Accepted: 08/24/2020] [Indexed: 12/14/2022] Open
Abstract
Endogenous retroviruses (ERVs) were usually silenced by various histone modifications on histone H3 variants and respective histone chaperones in embryonic stem cells (ESCs). However, it is still unknown whether chaperones of other histones could repress ERVs. Here, we show that H2A/H2B histone chaperone FACT plays a critical role in silencing ERVs and ERV-derived cryptic promoters in ESCs. Loss of FACT component Ssrp1 activated MERVL whereas the re-introduction of Ssrp1 rescued the phenotype. Additionally, Ssrp1 interacted with MERVL and suppressed cryptic transcription of MERVL-fused genes. Remarkably, Ssrp1 interacted with and recruited H2B deubiquitinase Usp7 to Ssrp1 target genes. Suppression of Usp7 caused similar phenotypes as loss of Ssrp1. Furthermore, Usp7 acted by deubiquitinating H2Bub and thereby repressed the expression of MERVL-fused genes. Taken together, our study uncovers a unique mechanism by which FACT complex silences ERVs and ERV-derived cryptic promoters in ESCs.
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Affiliation(s)
- Fuquan Chen
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China
- College of Pharmacy, Nankai University, Tianjin 300350, People's Republic of China
| | - Weiyu Zhang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China
- College of Pharmacy, Nankai University, Tianjin 300350, People's Republic of China
| | - Dan Xie
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China
- College of Pharmacy, Nankai University, Tianjin 300350, People's Republic of China
| | - Tingting Gao
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China
- College of Pharmacy, Nankai University, Tianjin 300350, People's Republic of China
| | - Zhiqiang Dong
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China
- College of Life Sciences, Nankai University, Tianjin 300307, People's Republic of China
| | - Xinyi Lu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China
- College of Pharmacy, Nankai University, Tianjin 300350, People's Republic of China
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115
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Posttranscriptional regulation of human endogenous retroviruses by RNA-binding motif protein 4, RBM4. Proc Natl Acad Sci U S A 2020; 117:26520-26530. [PMID: 33020268 DOI: 10.1073/pnas.2005237117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The human genome encodes for over 1,500 RNA-binding proteins (RBPs), which coordinate regulatory events on RNA transcripts. Most studies of RBPs have concentrated on their action on host protein-encoding mRNAs, which constitute a minority of the transcriptome. A widely neglected subset of our transcriptome derives from integrated retroviral elements, termed endogenous retroviruses (ERVs), that comprise ∼8% of the human genome. Some ERVs have been shown to be transcribed under physiological and pathological conditions, suggesting that sophisticated regulatory mechanisms to coordinate and prevent their ectopic expression exist. However, it is unknown how broadly RBPs and ERV transcripts directly interact to provide a posttranscriptional layer of regulation. Here, we implemented a computational pipeline to determine the correlation of expression between individual RBPs and ERVs from single-cell or bulk RNA-sequencing data. One of our top candidates for an RBP negatively regulating ERV expression was RNA-binding motif protein 4 (RBM4). We used photoactivatable ribonucleoside-enhanced cross-linking and immunoprecipitation to demonstrate that RBM4 indeed bound ERV transcripts at CGG consensus elements. Loss of RBM4 resulted in an elevated transcript level of bound ERVs of the HERV-K and -H families, as well as increased expression of HERV-K envelope protein. We pinpointed RBM4 regulation of HERV-K to a CGG-containing element that is conserved in the LTRs of HERV-K-10, -K-11, and -K-20, and validated the functionality of this site using reporter assays. In summary, we systematically identified RBPs that may regulate ERV function and demonstrate a role for RBM4 in controlling ERV expression.
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116
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Global hyperactivation of enhancers stabilizes human and mouse naive pluripotency through inhibition of CDK8/19 Mediator kinases. Nat Cell Biol 2020; 22:1223-1238. [PMID: 32989249 DOI: 10.1038/s41556-020-0573-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 08/07/2020] [Indexed: 12/11/2022]
Abstract
Pluripotent stem cells (PSCs) transition between cell states in vitro, reflecting developmental changes in the early embryo. PSCs can be stabilized in the naive state by blocking extracellular differentiation stimuli, particularly FGF-MEK signalling. Here, we report that multiple features of the naive state in human and mouse PSCs can be recapitulated without affecting FGF-MEK signalling or global DNA methylation. Mechanistically, chemical inhibition of CDK8 and CDK19 (hereafter CDK8/19) kinases removes their ability to repress the Mediator complex at enhancers. CDK8/19 inhibition therefore increases Mediator-driven recruitment of RNA polymerase II (RNA Pol II) to promoters and enhancers. This efficiently stabilizes the naive transcriptional program and confers resistance to enhancer perturbation by BRD4 inhibition. Moreover, naive pluripotency during embryonic development coincides with a reduction in CDK8/19. We conclude that global hyperactivation of enhancers drives naive pluripotency, and this can be achieved in vitro by inhibiting CDK8/19 kinase activity. These principles may apply to other contexts of cellular plasticity.
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117
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Abstract
Multicellular eukaryotic genomes show enormous differences in size. A substantial part of this variation is due to the presence of transposable elements (TEs). They contribute significantly to a cell's mass of DNA and have the potential to become involved in host gene control. We argue that the suppression of their activities by methylation of the C-phosphate-G (CpG) dinucleotide in DNA is essential for their long-term accommodation in the host genome and, therefore, to its expansion. An inevitable consequence of cytosine methylation is an increase in C-to-T transition mutations via deamination, which causes CpG loss. Cytosine deamination is often needed for TEs to take on regulatory functions in the host genome. Our study of the whole-genome sequences of 53 organisms showed a positive correlation between the size of a genome and the percentage of TEs it contains, as well as a negative correlation between size and the CpG observed/expected (O/E) ratio in both TEs and the host DNA. TEs are seldom found at promoters and transcription start sites, but they are found more at enhancers, particularly after they have accumulated C-to-T and other mutations. Therefore, the methylation of TE DNA allows for genome expansion and also leads to new opportunities for gene control by TE-based regulatory sites.
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118
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van der Kuyl AC, Berkhout B. Viruses in the reproductive tract: On their way to the germ line? Virus Res 2020; 286:198101. [PMID: 32710926 DOI: 10.1016/j.virusres.2020.198101] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/17/2020] [Accepted: 07/18/2020] [Indexed: 01/13/2023]
Abstract
Studies of vertebrate genomes have indicated that all species contain in their chromosomes stretches of DNA with sequence similarity to viral genomes. How such 'endogenous' viral elements (EVEs) ended up in host genomes is usually explained in general terms such as 'they entered the germ line at some point during evolution'. This seems a correct statement, but is also rather imprecise. The vast number of endogenous viral sequences suggest that common routes to the 'germ line' may exist, as relying on chance alone may not easily explain the abundance of EVEs in modern mammalian genomes. An increasing number of virus types have been detected in human semen and a growing number of studies have reported on viral infections that cause male infertility or subfertility and on viral infections that threaten in vitro fertilisation practices. Thus, it is timely to survey the pathway(s) that viruses can use to gain access to the human germ line. Embryo transfer and semen quality studies in livestock form another source of relevant information because virus infection during reproduction is clearly unwanted, as is the case for the human situation. In this review, studies on viruses in the male and female reproductive tract and in the early embryo will be discussed to propose a plausible viral route to the mammalian germ line.
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Affiliation(s)
- Antoinette Cornelia van der Kuyl
- Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam University Medical Centers, Amsterdam, The Netherlands.
| | - Ben Berkhout
- Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
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119
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Xue B, Sechi LA, Kelvin DJ. Human Endogenous Retrovirus K (HML-2) in Health and Disease. Front Microbiol 2020; 11:1690. [PMID: 32765477 PMCID: PMC7380069 DOI: 10.3389/fmicb.2020.01690] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 06/29/2020] [Indexed: 02/05/2023] Open
Abstract
Human endogenous retroviruses (HERVs) are derived from exogenous retrovirus infections in the evolution of primates and account for about 8% of the human genome. They were considered as silent passengers within our genomes for a long time, however, reactivation of HERVs has been associated with tumors and autoimmune diseases, especially the HERV-K (HML-2) family, the most recent integration groups with the least number of mutations and the most biologically active to encode functional retroviral proteins and produce retrovirus-like particles. Increasing studies are committed to determining the potential role of HERV-K (HML-2) in pathogenicity. Although there is still no evidence for HERV-K (HML-2) as a direct cause of diseases, aberrant expression profiles of the HERV-K (HML-2) transcripts and their regulatory function to their proximal host-genes were identified in different diseases. In this review, we summarized the advances between HERV-K (HML-2) and diseases to provide basis for further studies on the causal relationship between HERV-K (HML-2) and diseases. We recommended more attention to polymorphic integrated HERV-K (HML-2) loci which could be genetic causative factors and be associated with inter-individual differences in tumorigenesis and autoimmune diseases.
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Affiliation(s)
- Bei Xue
- Division of Immunology, Shantou University Medical College, Shantou, China
- Department of Microbiology and Immunology, Canadian Center for Vaccinology, Dalhousie University, Halifax, NS, Canada
| | - Leonardo A. Sechi
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
- Mediterranean Center for Disease Control, University of Sassari, Sassari, Italy
| | - David J. Kelvin
- Division of Immunology, Shantou University Medical College, Shantou, China
- Department of Microbiology and Immunology, Canadian Center for Vaccinology, Dalhousie University, Halifax, NS, Canada
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
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120
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Regulation of stem cell function and neuronal differentiation by HERV-K via mTOR pathway. Proc Natl Acad Sci U S A 2020; 117:17842-17853. [PMID: 32669437 DOI: 10.1073/pnas.2002427117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Stem cells are capable of unlimited proliferation but can be induced to form brain cells. Factors that specifically regulate human development are poorly understood. We found that human stem cells expressed high levels of the envelope protein of an endogenized human-specific retrovirus (HERV-K, HML-2) from loci in chromosomes 12 and 19. The envelope protein was expressed on the cell membrane of the stem cells and was critical in maintaining the stemness via interactions with CD98HC, leading to triggering of human-specific signaling pathways involving mammalian target of rapamycin (mTOR) and lysophosphatidylcholine acyltransferase (LPCAT1)-mediated epigenetic changes. Down-regulation or epigenetic silencing of HML-2 env resulted in dissociation of the stem cell colonies and enhanced differentiation along neuronal pathways. Thus HML-2 regulation is critical for human embryonic and neurodevelopment, while it's dysregulation may play a role in tumorigenesis and neurodegeneration.
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121
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Chen X, Li D. ERVcaller: identifying polymorphic endogenous retrovirus and other transposable element insertions using whole-genome sequencing data. Bioinformatics 2020; 35:3913-3922. [PMID: 30895294 DOI: 10.1093/bioinformatics/btz205] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 02/28/2019] [Accepted: 03/19/2019] [Indexed: 12/12/2022] Open
Abstract
MOTIVATION Approximately 8% of the human genome is derived from endogenous retroviruses (ERVs). In recent years, an increasing number of human diseases have been found to be associated with ERVs. However, it remains challenging to accurately detect the full spectrum of polymorphic (unfixed) ERVs using whole-genome sequencing (WGS) data. RESULTS We designed a new tool, ERVcaller, to detect and genotype transposable element (TE) insertions, including ERVs, in the human genome. We evaluated ERVcaller using both simulated and real benchmark WGS datasets. Compared to existing tools, ERVcaller consistently obtained both the highest sensitivity and precision for detecting simulated ERV and other TE insertions derived from real polymorphic TE sequences. For the WGS data from the 1000 Genomes Project, ERVcaller detected the largest number of TE insertions per sample based on consensus TE loci. By analyzing the experimentally verified TE insertions, ERVcaller had 94.0% TE detection sensitivity and 96.6% genotyping accuracy. Polymerase chain reaction and Sanger sequencing in a small sample set verified 86.7% of examined insertion statuses and 100% of examined genotypes. In conclusion, ERVcaller is capable of detecting and genotyping TE insertions using WGS data with both high sensitivity and precision. This tool can be applied broadly to other species. AVAILABILITY AND IMPLEMENTATION http://www.uvm.edu/genomics/software/ERVcaller.html. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Xun Chen
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, USA
| | - Dawei Li
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, USA.,Neuroscience, Behavior, and Health Initiative, University of Vermont, Burlington, VT, USA.,Department of Computer Science, University of Vermont, Burlington, VT, USA
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122
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DNA methylation dynamics at transposable elements in mammals. Essays Biochem 2020; 63:677-689. [PMID: 31654072 DOI: 10.1042/ebc20190039] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 09/29/2019] [Accepted: 09/30/2019] [Indexed: 12/18/2022]
Abstract
Transposable elements dominate the mammalian genome, but their contribution to genetic and epigenetic regulation has been largely overlooked. This was in part due to technical limitations, which made the study of repetitive sequences at single copy resolution difficult. The advancement of next-generation sequencing assays in the last decade has greatly enhanced our understanding of transposable element function. In some instances, specific transposable elements are thought to have been co-opted into regulatory roles during both mouse and human development, while in disease such regulatory potential can contribute to malignancy. DNA methylation is arguably the best characterised regulator of transposable element activity. DNA methylation is associated with transposable element repression, and acts to limit their genotoxic potential. In specific developmental contexts, erasure of DNA methylation is associated with a burst of transposable element expression. Developmental regulation of DNA methylation enables transposon activation, ensuring their survival and propagation throughout the host genome, and also allows the host access to regulatory sequences encoded within the elements. Here I discuss DNA methylation at transposable elements, describing its function and dynamic regulation throughout murine and human development.
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123
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Wang J, Huang J, Shi G. Retrotransposons in pluripotent stem cells. CELL REGENERATION 2020; 9:4. [PMID: 32588192 PMCID: PMC7306833 DOI: 10.1186/s13619-020-00046-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/19/2019] [Indexed: 12/18/2022]
Abstract
Transposable elements constitute about half of the mammalian genome, and can be divided into two classes: the class I (retrotransposons) and the class II (DNA transposons). A few hundred types of retrotransposons, which are dynamic and stage specific, have been annotated. The copy numbers and genomic locations are significantly varied in species. Retrotransposons are active in germ cells, early embryos and pluripotent stem cells (PSCs) correlated with low levels of DNA methylation in epigenetic regulation. Some key pluripotency transcriptional factors (such as OCT4, SOX2, and NANOG) bind retrotransposons and regulate their activities in PSCs, suggesting a vital role of retrotransposons in pluripotency maintenance and self-renewal. In response to retrotransposons transposition, cells employ a number of silencing mechanisms, such as DNA methylation and histone modification. This review summarizes expression patterns, functions, and regulation of retrotransposons in PSCs and early embryonic development.
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Affiliation(s)
- Jingwen Wang
- School of Life Sciences, SunYat-sen University, Guangzhou, 510275, P. R. China
| | - Junjiu Huang
- School of Life Sciences, SunYat-sen University, Guangzhou, 510275, P. R. China. .,Key Laboratory of Reproductive Medicine of Guangdong Province, School of Life Sciences and the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510275, China. .,Key Laboratory of Reproductive Medicine of Guangdong Province, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China.
| | - Guang Shi
- School of Life Sciences, SunYat-sen University, Guangzhou, 510275, P. R. China.
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124
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Chen X, Zheng Y, Lei A, Zhang H, Niu H, Li X, Zhang P, Liao M, Lv Y, Zhu Z, Pan C, Dong W, Chen H, Wu D, Liu W, Hamer G, Zeng S, Zeng W. Early cleavage of preimplantation embryos is regulated by tRNA Gln-TTG-derived small RNAs present in mature spermatozoa. J Biol Chem 2020; 295:10885-10900. [PMID: 32487749 DOI: 10.1074/jbc.ra120.013003] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 05/27/2020] [Indexed: 12/12/2022] Open
Abstract
tRNA-derived small RNAs (tsRNAs) from spermatozoa could act as acquired epigenetic factors and contribute to offspring phenotypes. However, the roles of specific tsRNAs in early embryo development remain to be elucidated. Here, using pigs as a research model, we probed the tsRNA dynamics during spermatogenesis and sperm maturation and demonstrated the delivery of tsRNAs from semen-derived exosomes to spermatozoa. By microinjection of antisense sequences into in vitro fertilized oocytes and subsequent single-cell RNA-seq of embryos, we identified a specific functional tsRNA group (termed here Gln-TTGs) that participate in the early cleavage of porcine preimplantation embryos, probably by regulating cell cycle-associated genes and retrotransposons. We conclude that specific tsRNAs present in mature spermatozoa play significant roles in preimplantation embryo development.
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Affiliation(s)
- Xiaoxu Chen
- Key Laboratory for Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Yi Zheng
- Key Laboratory for Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Anmin Lei
- College of Veterinary Medicine, Shaanxi Stem Cell Engineering and Technology Center, Northwest A&F University, Yangling, Shaanxi, China
| | - Hanxue Zhang
- Laboratory of Animal Embryonic Biotechnology, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Huimin Niu
- College of Veterinary Medicine, Shaanxi Stem Cell Engineering and Technology Center, Northwest A&F University, Yangling, Shaanxi, China
| | - Xueliang Li
- Key Laboratory for Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Pengfei Zhang
- Key Laboratory for Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Mingzhi Liao
- College of Life Science, Northwest A&F University, Yangling, Shaanxi, China
| | - Yinghua Lv
- College of Chemistry and Pharmacy, Northwest A&F University, Yangling, Shaanxi, China
| | - Zhendong Zhu
- Key Laboratory for Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Chuanying Pan
- Key Laboratory for Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Wuzi Dong
- Key Laboratory for Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Hong Chen
- Key Laboratory for Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - De Wu
- Key Laboratory for Animal Disease Resistance Nutrition of the Ministry of Education of China, Institute of Animal Nutrition, Sichuan Agricultural University, Ya'an Chengdu, China
| | - Wansheng Liu
- Department of Animal Science, Center for Reproductive Biology and Health, College of Agricultural Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Geert Hamer
- Reproductive Biology Laboratory, Center for Reproductive Medicine, Amsterdam Reproduction & Development Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Shenming Zeng
- Laboratory of Animal Embryonic Biotechnology, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Wenxian Zeng
- Key Laboratory for Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
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125
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O'Neill K, Brocks D, Hammell MG. Mobile genomics: tools and techniques for tackling transposons. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190345. [PMID: 32075565 PMCID: PMC7061981 DOI: 10.1098/rstb.2019.0345] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2019] [Indexed: 12/22/2022] Open
Abstract
Next-generation sequencing approaches have fundamentally changed the types of questions that can be asked about gene function and regulation. With the goal of approaching truly genome-wide quantifications of all the interaction partners and downstream effects of particular genes, these quantitative assays have allowed for an unprecedented level of detail in exploring biological interactions. However, many challenges remain in our ability to accurately describe and quantify the interactions that take place in those hard to reach and extremely repetitive regions of our genome comprised mostly of transposable elements (TEs). Tools dedicated to TE-derived sequences have lagged behind, making the inclusion of these sequences in genome-wide analyses difficult. Recent improvements, both computational and experimental, allow for the better inclusion of TE sequences in genomic assays and a renewed appreciation for the importance of TE biology. This review will discuss the recent improvements that have been made in the computational analysis of TE-derived sequences as well as the areas where such analysis still proves difficult. This article is part of a discussion meeting issue 'Crossroads between transposons and gene regulation'.
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Affiliation(s)
- Kathryn O'Neill
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - David Brocks
- Department of Computer Science and Applied Mathematics, The Weizmann Institute of Science, Rehovot, Israel
| | - Molly Gale Hammell
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
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126
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Gemenetzi M, Lotery AJ. Epigenetics in age-related macular degeneration: new discoveries and future perspectives. Cell Mol Life Sci 2020; 77:807-818. [PMID: 31897542 PMCID: PMC7058675 DOI: 10.1007/s00018-019-03421-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 12/04/2019] [Accepted: 12/10/2019] [Indexed: 12/13/2022]
Abstract
The study of epigenetics has explained some of the 'missing heritability' of age-related macular degeneration (AMD). The epigenome also provides a substantial contribution to the organisation of the functional retina. There is emerging evidence of specific epigenetic mechanisms associated with AMD. This 'AMD epigenome' may offer the chance to develop novel AMD treatments.
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Affiliation(s)
- M Gemenetzi
- NIHR Biomedical Research Centre At Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, 162 City Road, London, EC1V 2PD, UK
| | - A J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University Hospital Southampton, University of Southampton, South Lab and Path Block, Mailpoint 806, Level D, Southampton, SO16 6YD, UK.
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127
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Percharde M, Sultana T, Ramalho-Santos M. What Doesn't Kill You Makes You Stronger: Transposons as Dual Players in Chromatin Regulation and Genomic Variation. Bioessays 2020; 42:e1900232. [PMID: 32053231 DOI: 10.1002/bies.201900232] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/10/2020] [Indexed: 12/22/2022]
Abstract
Transposable elements (TEs) are sequences currently or historically mobile, and are present across all eukaryotic genomes. A growing interest in understanding the regulation and function of TEs has revealed seemingly dichotomous roles for these elements in evolution, development, and disease. On the one hand, many gene regulatory networks owe their organization to the spread of cis-elements and DNA binding sites through TE mobilization during evolution. On the other hand, the uncontrolled activity of transposons can generate mutations and contribute to disease, including cancer, while their increased expression may also trigger immune pathways that result in inflammation or senescence. Interestingly, TEs have recently been found to have novel essential functions during mammalian development. Here, the function and regulation of TEs are discussed, with a focus on LINE1 in mammals. It is proposed that LINE1 is a beneficial endogenous dual regulator of gene expression and genomic diversity during mammalian development, and that both of these functions may be detrimental if deregulated in disease contexts.
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Affiliation(s)
- Michelle Percharde
- MRC London Institute of Medical Sciences (LMS), London, W12 0NN, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
| | - Tania Sultana
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, M5T 3L9, Ontario, Canada
| | - Miguel Ramalho-Santos
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, M5T 3L9, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, M5S 1A8, Ontario, Canada
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128
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Zhang W, Chen F, Chen R, Xie D, Yang J, Zhao X, Guo R, Zhang Y, Shen Y, Göke J, Liu L, Lu X. Zscan4c activates endogenous retrovirus MERVL and cleavage embryo genes. Nucleic Acids Res 2019; 47:8485-8501. [PMID: 31304534 PMCID: PMC7145578 DOI: 10.1093/nar/gkz594] [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: 02/25/2019] [Revised: 06/24/2019] [Accepted: 06/28/2019] [Indexed: 01/09/2023] Open
Abstract
Endogenous retroviruses (ERVs) contribute to ∼10 percent of the mouse genome. They are often silenced in differentiated somatic cells but differentially expressed at various embryonic developmental stages. A minority of mouse embryonic stem cells (ESCs), like 2-cell cleavage embryos, highly express ERV MERVL. However, the role of ERVs and mechanism of their activation in these cells are still poorly understood. In this study, we investigated the regulation and function of the stage-specific expressed ERVs, with a particular focus on the totipotency marker MT2/MERVL. We show that the transcription factor Zscan4c functions as an activator of MT2/MERVL and 2-cell/4-cell embryo genes. Zinc finger domains of Zscan4c play an important role in this process. In addition, Zscan4c interacts with MT2 and regulates MT2-nearby 2-cell/4-cell genes through promoting enhancer activity of MT2. Furthermore, MT2 activation is accompanied by enhanced H3K4me1, H3K27ac, and H3K14ac deposition on MT2. Zscan4c also interacts with GBAF chromatin remodelling complex through SCAN domain to further activate MT2 enhancer activity. Taken together, we delineate a previously unrecognized regulatory axis that Zscan4c interacts with and activates MT2/MERVL loci and their nearby genes through epigenetic regulation.
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Affiliation(s)
- Weiyu Zhang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China.,College of Pharmacy, Nankai University, Tianjin 300350, People's Republic of China
| | - Fuquan Chen
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China.,College of Pharmacy, Nankai University, Tianjin 300350, People's Republic of China
| | - Ruiqing Chen
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China.,College of Pharmacy, Nankai University, Tianjin 300350, People's Republic of China
| | - Dan Xie
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China.,College of Pharmacy, Nankai University, Tianjin 300350, People's Republic of China
| | - Jiao Yang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China.,College of Life Sciences, Nankai University, Tianjin 300071, People's Republic of China
| | - Xin Zhao
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China.,College of Pharmacy, Nankai University, Tianjin 300350, People's Republic of China
| | - Renpeng Guo
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China.,College of Life Sciences, Nankai University, Tianjin 300071, People's Republic of China
| | - Yongwang Zhang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China.,College of Pharmacy, Nankai University, Tianjin 300350, People's Republic of China
| | - Yang Shen
- Computational and Systems Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Jonathan Göke
- Computational and Systems Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Lin Liu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China.,College of Life Sciences, Nankai University, Tianjin 300071, People's Republic of China
| | - Xinyi Lu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, People's Republic of China.,College of Pharmacy, Nankai University, Tianjin 300350, People's Republic of China
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129
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Casanova M, Moscatelli M, Chauvière LÉ, Huret C, Samson J, Liyakat Ali TM, Rosspopoff O, Rougeulle C. A primate-specific retroviral enhancer wires the XACT lncRNA into the core pluripotency network in humans. Nat Commun 2019; 10:5652. [PMID: 31827084 PMCID: PMC6906429 DOI: 10.1038/s41467-019-13551-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/05/2019] [Indexed: 12/22/2022] Open
Abstract
Transposable elements (TEs) have been proposed to play an important role in driving the expansion of gene regulatory networks during mammalian evolution, notably by contributing to the evolution and function of long non-coding RNAs (lncRNAs). XACT is a primate-specific TE-derived lncRNA that coats active X chromosomes in pluripotent cells and may contribute to species-specific regulation of X-chromosome inactivation. Here we explore how different families of TEs have contributed to shaping the XACT locus and coupling its expression to pluripotency. Through a combination of sequence analysis across primates, transcriptional interference, and genome editing, we identify a critical enhancer for the regulation of the XACT locus that evolved from an ancestral group of mammalian endogenous retroviruses (ERVs), prior to the emergence of XACT. This ERV was hijacked by younger hominoid-specific ERVs that gave rise to the promoter of XACT, thus wiring its expression to the pluripotency network. This work illustrates how retroviral-derived sequences may intervene in species-specific regulatory pathways.
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Affiliation(s)
- Miguel Casanova
- Université de Paris, Epigenetics and Cell Fate, CNRS, F-75013, Paris, France.
| | | | | | - Christophe Huret
- Université de Paris, Epigenetics and Cell Fate, CNRS, F-75013, Paris, France
| | - Julia Samson
- Université de Paris, Epigenetics and Cell Fate, CNRS, F-75013, Paris, France
| | | | - Olga Rosspopoff
- Université de Paris, Epigenetics and Cell Fate, CNRS, F-75013, Paris, France
| | - Claire Rougeulle
- Université de Paris, Epigenetics and Cell Fate, CNRS, F-75013, Paris, France.
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130
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Pehrsson EC, Choudhary MNK, Sundaram V, Wang T. The epigenomic landscape of transposable elements across normal human development and anatomy. Nat Commun 2019; 10:5640. [PMID: 31822674 PMCID: PMC6904449 DOI: 10.1038/s41467-019-13555-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 11/12/2019] [Indexed: 12/21/2022] Open
Abstract
Transposable elements (TEs) have deposited functional regulatory elements throughout the human genome. Although most are silenced, certain TEs have been co-opted by the host. However, a comprehensive, multidimensional picture of the contribution of TEs to normal human gene regulation is still lacking. Here, we quantify the epigenomic status of TEs across human anatomy and development using data from the Roadmap Epigenomics Project. We find that TEs encompass a quarter of the human regulatory epigenome, and 47% of elements can be in an active regulatory state. We demonstrate that SINEs are enriched relative to other classes for active and transcribed marks, that TEs encompass a higher proportion of enhancer states in the hematopoietic lineage, and that DNA methylation of Alu elements decreases with age, corresponding with a loss of CpG islands. Finally, we identify TEs that may perform an evolutionarily conserved regulatory function, providing a systematic profile of TE activity in normal human tissue.
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Affiliation(s)
- Erica C Pehrsson
- Department of Genetics, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, MO, 63110, USA.
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
| | - Mayank N K Choudhary
- Department of Genetics, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, MO, 63110, USA
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Vasavi Sundaram
- Department of Genetics, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, MO, 63110, USA
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Ting Wang
- Department of Genetics, Washington University School of Medicine, 4515 McKinley Avenue, St. Louis, MO, 63110, USA.
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, 63108, USA.
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131
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Ansaloni F, Scarpato M, Di Schiavi E, Gustincich S, Sanges R. Exploratory analysis of transposable elements expression in the C. elegans early embryo. BMC Bioinformatics 2019; 20:484. [PMID: 31757208 PMCID: PMC6873666 DOI: 10.1186/s12859-019-3088-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 09/10/2019] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Transposable Elements (TE) are mobile sequences that make up large portions of eukaryote genomes. The functions they play within the complex cellular architecture are still not clearly understood, but it is becoming evident that TE have a role in several physiological and pathological processes. In particular, it has been shown that TE transcription is necessary for the correct development of mice embryos and that their expression is able to finely modulate transcription of coding and non-coding genes. Moreover, their activity in the central nervous system (CNS) and other tissues has been correlated with the creation of somatic mosaicisms and with pathologies such as neurodevelopmental and neurodegenerative diseases as well as cancers. RESULTS We analyzed TE expression among different cell types of the Caenorhabditis elegans (C. elegans) early embryo asking if, where and when TE are expressed and whether their expression is correlated with genes playing a role in early embryo development. To answer these questions, we took advantage of a public C. elegans embryonic single-cell RNA-seq (sc-RNAseq) dataset and developed a bioinformatics pipeline able to quantify reads mapping specifically against TE, avoiding counting reads mapping on TE fragments embedded in coding/non-coding transcripts. Our results suggest that i) canonical TE expression analysis tools, which do not discard reads mapping on TE fragments embedded in annotated transcripts, may over-estimate TE expression levels, ii) Long Terminal Repeats (LTR) elements are mostly expressed in undifferentiated cells and might play a role in pluripotency maintenance and activation of the innate immune response, iii) non-LTR are expressed in differentiated cells, in particular in neurons and nervous system-associated tissues, and iv) DNA TE are homogenously expressed throughout the C. elegans early embryo development. CONCLUSIONS TE expression appears finely modulated in the C. elegans early embryo and different TE classes are expressed in different cell types and stages, suggesting that TE might play diverse functions during early embryo development.
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Affiliation(s)
- Federico Ansaloni
- Area of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Margherita Scarpato
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Elia Di Schiavi
- Institute of Biosciences and BioResources (IBBR), CNR, Napoli, Italy
| | - Stefano Gustincich
- Area of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Remo Sanges
- Area of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
- Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Napoli, Italy
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132
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Transposable element expression in tumors is associated with immune infiltration and increased antigenicity. Nat Commun 2019; 10:5228. [PMID: 31745090 PMCID: PMC6864081 DOI: 10.1038/s41467-019-13035-2] [Citation(s) in RCA: 124] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 10/15/2019] [Indexed: 12/19/2022] Open
Abstract
Profound global loss of DNA methylation is a hallmark of many cancers. One potential consequence of this is the reactivation of transposable elements (TEs) which could stimulate the immune system via cell-intrinsic antiviral responses. Here, we develop REdiscoverTE, a computational method for quantifying genome-wide TE expression in RNA sequencing data. Using The Cancer Genome Atlas database, we observe increased expression of over 400 TE subfamilies, of which 262 appear to result from a proximal loss of DNA methylation. The most recurrent TEs are among the evolutionarily youngest in the genome, predominantly expressed from intergenic loci, and associated with antiviral or DNA damage responses. Treatment of glioblastoma cells with a demethylation agent results in both increased TE expression and de novo presentation of TE-derived peptides on MHC class I molecules. Therapeutic reactivation of tumor-specific TEs may synergize with immunotherapy by inducing inflammation and the display of potentially immunogenic neoantigens. Treatment with demethylation agents can reactivate transposable elements. Here in glioblastoma, the authors also show that this is accompanied by de novo presentation of TE-derived peptides on MHC class I molecules.
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133
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Ohishi H, Au Yeung WK, Unoki M, Ichiyanagi K, Fukuda K, Maenohara S, Shirane K, Chiba H, Sado T, Sasaki H. Characterization of genetic-origin-dependent monoallelic expression in mouse embryonic stem cells. Genes Cells 2019; 25:54-64. [PMID: 31733167 DOI: 10.1111/gtc.12736] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/12/2019] [Accepted: 11/13/2019] [Indexed: 12/19/2022]
Abstract
Monoallelic gene expression occurs in various mammalian cells and can be regulated genetically, epigenetically and/or stochastically. We identified 145 monoallelically expressed genes (MoEGs), including seven known imprinted genes, in mouse embryonic stem cells (ESCs) derived from reciprocal F1 hybrid blastocysts and cultured in 2i/LIF. As all MoEGs except for the imprinted genes were expressed in a genetic-origin-dependent manner, we focused on this class of MoEGs for mechanistic studies. We showed that a majority of the genetic-origin-dependent MoEGs identified in 2i/LIF ESCs remain monoallelically expressed in serum/LIF ESCs, but become more relaxed or even biallelically expressed upon differentiation. These MoEGs and their regulatory regions were highly enriched for single nucleotide polymorphisms. In addition, some MoEGs were associated with retrotransposon insertions/deletions, consistent with the fact that certain retrotransposons act as regulatory elements in pluripotent stem cells. Interestingly, most MoEGs showed allelic differences in enrichment of histone H3K27me and H3K4me marks, linking allelic epigenetic differences and monoallelic expression. In contrast, there was little or no allelic difference in CpG methylation or H3K9me. Taken together, our study highlights the impact of genetic variation including single nucleotide polymorphisms and retrotransposon insertions/deletions on monoallelic epigenetic marks and expression in ESCs.
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Affiliation(s)
- Hiroaki Ohishi
- Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Wan Kin Au Yeung
- Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Motoko Unoki
- Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Kenji Ichiyanagi
- Laboratory of Genome and Epigenome Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Kei Fukuda
- Cellular Memory Laboratory, RIKEN, Wako, Japan
| | - Shoji Maenohara
- Gynecology Service, National Hospital Organization Kyushu Cancer Center, Fukuoka, Japan
| | - Kenjiro Shirane
- Department of Medical Genetics, The University of British Columbia, Vancouver, BC, Canada
| | - Hatsune Chiba
- Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.,Department of Informative Genetics, Environment and Genome Research Center, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Takashi Sado
- Department of Advanced Bioscience, Graduate School of Agriculture, KINDAI University, Nara, Japan
| | - Hiroyuki Sasaki
- Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
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134
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Es-Haghi M, Godakumara K, Häling A, Lättekivi F, Lavrits A, Viil J, Andronowska A, Nafee T, James V, Jaakma Ü, Salumets A, Fazeli A. Specific trophoblast transcripts transferred by extracellular vesicles affect gene expression in endometrial epithelial cells and may have a role in embryo-maternal crosstalk. Cell Commun Signal 2019; 17:146. [PMID: 31727082 PMCID: PMC6854687 DOI: 10.1186/s12964-019-0448-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 10/04/2019] [Indexed: 12/14/2022] Open
Abstract
Background Successful establishment of pregnancy hinges on appropriate communication between the embryo and the uterus prior to implantation, but the nature of this communication remains poorly understood. Here, we tested the hypothesis that the endometrium is receptive to embryo-derived signals in the form of RNA. Methods We have utilized a non-contact co culture system to simulate the conditions of pre implantation environment of the uterus. We bioorthogonally tagged embryonic RNA and tracked the transferred transcripts to endometrium. Transferred transcripts were separated from endometrial transcripts and sequenced. Changes in endometrial transcripts were quantified using quantitative PCR. Results We show that three specific transcripts are transferred to endometrial cells. We subsequently demonstrate a role of extracellular vesicles (EVs) in this process, as EVs obtained from cultured trophoblast spheroids incubated with endometrial cells induced down-regulation of all the three identified transcripts in endometrial cells. Finally, we show that EVs/nanoparticles captured from conditioned culture media of viable embryos as opposed to degenerating embryos induce ZNF81 down-regulation in endometrial cells, hinting at the functional importance of this intercellular communication. Conclusion Ultimately, our findings demonstrate the existence of an RNA-based communication which may be of critical importance for the establishment of pregnancy.
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Affiliation(s)
- Masoumeh Es-Haghi
- Department of Pathophysiology, Institute of Biomedicine and Translational Medicine, Faculty of Medicine, Tartu University, Tartu, Estonia
| | - Kasun Godakumara
- Department of Pathophysiology, Institute of Biomedicine and Translational Medicine, Faculty of Medicine, Tartu University, Tartu, Estonia
| | - Annika Häling
- Department of Pathophysiology, Institute of Biomedicine and Translational Medicine, Faculty of Medicine, Tartu University, Tartu, Estonia
| | - Freddy Lättekivi
- Department of Pathophysiology, Institute of Biomedicine and Translational Medicine, Faculty of Medicine, Tartu University, Tartu, Estonia
| | - Arina Lavrits
- Department of Pathophysiology, Institute of Biomedicine and Translational Medicine, Faculty of Medicine, Tartu University, Tartu, Estonia
| | - Janeli Viil
- Department of Pathophysiology, Institute of Biomedicine and Translational Medicine, Faculty of Medicine, Tartu University, Tartu, Estonia
| | - Aneta Andronowska
- Department of Hormonal Action Mechanisms, Institute of Animal Reproduction and Food Research Polish Academy of Sciences, Olsztyn, Poland
| | - Tamer Nafee
- Academic unit of reproductive and developmental medicine, Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
| | - Victoria James
- School of Veterinary Medicine and Science, University of Nottingham, Nottingham, LE12 5RD, UK
| | - Ülle Jaakma
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Fr. R. Kreutzwaldi 1, 51006, Tartu, Estonia
| | - Andres Salumets
- Department of Obstetrics and Gynecology, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia.,Competence Centre on Health Technologies, Tartu, Estonia.,Department of Biomedicine, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia.,Department of Obstetrics and Gynaecology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Alireza Fazeli
- Department of Pathophysiology, Institute of Biomedicine and Translational Medicine, Faculty of Medicine, Tartu University, Tartu, Estonia. .,Academic unit of reproductive and developmental medicine, Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK.
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135
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Leng L, Sun J, Huang J, Gong F, Yang L, Zhang S, Yuan X, Fang F, Xu X, Luo Y, Bolund L, Peters BA, Lu G, Jiang T, Xu F, Lin G. Single-Cell Transcriptome Analysis of Uniparental Embryos Reveals Parent-of-Origin Effects on Human Preimplantation Development. Cell Stem Cell 2019; 25:697-712.e6. [DOI: 10.1016/j.stem.2019.09.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 06/27/2019] [Accepted: 09/03/2019] [Indexed: 11/16/2022]
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136
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Szczerbinska I, Gonzales KAU, Cukuroglu E, Ramli MNB, Lee BPG, Tan CP, Wong CK, Rancati GI, Liang H, Göke J, Ng HH, Chan YS. A Chemically Defined Feeder-free System for the Establishment and Maintenance of the Human Naive Pluripotent State. Stem Cell Reports 2019; 13:612-626. [PMID: 31522974 PMCID: PMC6829768 DOI: 10.1016/j.stemcr.2019.08.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 08/12/2019] [Accepted: 08/15/2019] [Indexed: 01/28/2023] Open
Abstract
The distinct states of pluripotency in the pre- and post-implantation embryo can be captured in vitro as naive and primed pluripotent stem cell cultures, respectively. The study and application of the naive state remains hampered, particularly in humans, partially due to current culture protocols relying on extraneous undefined factors such as feeders. Here we performed a small-molecule screen to identify compounds that facilitate chemically defined establishment and maintenance of human feeder-independent naive embryonic (FINE) stem cells. The expression profile in genic and repetitive elements of FINE cells resembles the 8-cell-to-morula stage in vivo, and only differs from feeder-dependent naive cells in genes involved in cell-cell/cell-matrix interactions. FINE cells offer several technical advantages, such as increased amenability to transfection and a longer period of genomic stability, compared with feeder-dependent cells. Thus, FINE cells will serve as an accessible and useful system for scientific and translational applications of naïve pluripotent stem cells. High-throughput screen identifies small molecules modulating human naive pluripotency Induction and culture of human feeder-independent naive embryonic (FINE) stem cells FINE cells are molecularly equivalent to 4iLA hESCs FINE cells offer enhanced genomic stability and amenability to exogenous DNA uptake
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Affiliation(s)
- Iwona Szczerbinska
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore; Department of Biochemistry, National University of Singapore, Singapore 117559, Singapore
| | - Kevin Andrew Uy Gonzales
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore; Robin Chemers Neustein Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, 1230 York Avenue, New York City, NY 10065, USA
| | - Engin Cukuroglu
- Computational and Systems Biology, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore
| | - Muhammad Nadzim Bin Ramli
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore
| | - Bertha Pei Ge Lee
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore
| | - Cheng Peow Tan
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore
| | - Cheng Kit Wong
- Institute of Medical Biology, A(∗)STAR, 8A Biomedical Grove, Immunos #05, Singapore 138648, Singapore
| | - Giulia Irene Rancati
- Institute of Medical Biology, A(∗)STAR, 8A Biomedical Grove, Immunos #05, Singapore 138648, Singapore
| | - Hongqing Liang
- Division of Human Reproduction and Developmental Genetics, the Women's Hospital, Zhejiang University School of Medicine, Yuhangtang Road 866, Hangzhou, Zhejiang 310012, China; Institute of Genetics and Department of Genetics, Zhejiang University School of Medicine, Yuhangtang Road 866, Hangzhou, Zhejiang 310012, China
| | - Jonathan Göke
- Computational and Systems Biology, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore
| | - Huck-Hui Ng
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore; Department of Biochemistry, National University of Singapore, Singapore 117559, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117597, Singapore; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 639798, Singapore.
| | - Yun-Shen Chan
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore.
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137
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Zhang Y, Li T, Preissl S, Amaral ML, Grinstein JD, Farah EN, Destici E, Qiu Y, Hu R, Lee AY, Chee S, Ma K, Ye Z, Zhu Q, Huang H, Fang R, Yu L, Izpisua Belmonte JC, Wu J, Evans SM, Chi NC, Ren B. Transcriptionally active HERV-H retrotransposons demarcate topologically associating domains in human pluripotent stem cells. Nat Genet 2019; 51:1380-1388. [PMID: 31427791 PMCID: PMC6722002 DOI: 10.1038/s41588-019-0479-7] [Citation(s) in RCA: 177] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 07/09/2019] [Indexed: 12/24/2022]
Abstract
Chromatin architecture has been implicated in cell type-specific gene regulatory programs, yet how chromatin remodels during development remains to be fully elucidated. Here, by interrogating chromatin reorganization during human pluripotent stem cell (hPSC) differentiation, we discover a role for the primate-specific endogenous retrotransposon human endogenous retrovirus subfamily H (HERV-H) in creating topologically associating domains (TADs) in hPSCs. Deleting these HERV-H elements eliminates their corresponding TAD boundaries and reduces the transcription of upstream genes, while de novo insertion of HERV-H elements can introduce new TAD boundaries. The ability of HERV-H to create TAD boundaries depends on high transcription, as transcriptional repression of HERV-H elements prevents the formation of boundaries. This ability is not limited to hPSCs, as these actively transcribed HERV-H elements and their corresponding TAD boundaries also appear in pluripotent stem cells from other hominids but not in more distantly related species lacking HERV-H elements. Overall, our results provide direct evidence for retrotransposons in actively shaping cell type- and species-specific chromatin architecture.
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Affiliation(s)
- Yanxiao Zhang
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Ting Li
- Department of Medicine, Division of Cardiology, University of California San Diego, La Jolla, CA, USA
| | - Sebastian Preissl
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
- Center for Epigenomics, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Maria Luisa Amaral
- Bioinformatics and Systems Biology Graduate Program, University of California San Diego, La Jolla, CA, USA
| | - Jonathan D Grinstein
- Department of Medicine, Division of Cardiology, University of California San Diego, La Jolla, CA, USA
| | - Elie N Farah
- Department of Medicine, Division of Cardiology, University of California San Diego, La Jolla, CA, USA
- Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, CA, USA
| | - Eugin Destici
- Department of Medicine, Division of Cardiology, University of California San Diego, La Jolla, CA, USA
| | - Yunjiang Qiu
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
- Bioinformatics and Systems Biology Graduate Program, University of California San Diego, La Jolla, CA, USA
| | - Rong Hu
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Ah Young Lee
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Sora Chee
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Kaiyue Ma
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Zhen Ye
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Quan Zhu
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
| | - Hui Huang
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
- Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, CA, USA
| | - Rongxin Fang
- Ludwig Institute for Cancer Research, La Jolla, CA, USA
- Bioinformatics and Systems Biology Graduate Program, University of California San Diego, La Jolla, CA, USA
| | - Leqian Yu
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Jun Wu
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sylvia M Evans
- Department of Medicine, Division of Cardiology, University of California San Diego, La Jolla, CA, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - Neil C Chi
- Department of Medicine, Division of Cardiology, University of California San Diego, La Jolla, CA, USA.
- Institute of Genomic Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA.
| | - Bing Ren
- Ludwig Institute for Cancer Research, La Jolla, CA, USA.
- Center for Epigenomics, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA.
- Institute of Genomic Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA.
- Moores Cancer Center, School of Medicine, University of California San Diego, La Jolla, CA, USA.
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138
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Bendall ML, de Mulder M, Iñiguez LP, Lecanda-Sánchez A, Pérez-Losada M, Ostrowski MA, Jones RB, Mulder LCF, Reyes-Terán G, Crandall KA, Ormsby CE, Nixon DF. Telescope: Characterization of the retrotranscriptome by accurate estimation of transposable element expression. PLoS Comput Biol 2019; 15:e1006453. [PMID: 31568525 PMCID: PMC6786656 DOI: 10.1371/journal.pcbi.1006453] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 10/10/2019] [Accepted: 09/17/2019] [Indexed: 12/20/2022] Open
Abstract
Characterization of Human Endogenous Retrovirus (HERV) expression within the transcriptomic landscape using RNA-seq is complicated by uncertainty in fragment assignment because of sequence similarity. We present Telescope, a computational software tool that provides accurate estimation of transposable element expression (retrotranscriptome) resolved to specific genomic locations. Telescope directly addresses uncertainty in fragment assignment by reassigning ambiguously mapped fragments to the most probable source transcript as determined within a Bayesian statistical model. We demonstrate the utility of our approach through single locus analysis of HERV expression in 13 ENCODE cell types. When examined at this resolution, we find that the magnitude and breadth of the retrotranscriptome can be vastly different among cell types. Furthermore, our approach is robust to differences in sequencing technology and demonstrates that the retrotranscriptome has potential to be used for cell type identification. We compared our tool with other approaches for quantifying transposable element (TE) expression, and found that Telescope has the greatest resolution, as it estimates expression at specific TE insertions rather than at the TE subfamily level. Telescope performs highly accurate quantification of the retrotranscriptomic landscape in RNA-seq experiments, revealing a differential complexity in the transposable element biology of complex systems not previously observed. Telescope is available at https://github.com/mlbendall/telescope.
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Affiliation(s)
- Matthew L. Bendall
- Computational Biology Institute, Milken Institute School of Public Health, George Washington University, Washington, D.C., United States of America
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, N.Y., United States of America
| | - Miguel de Mulder
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, N.Y., United States of America
| | - Luis Pedro Iñiguez
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, N.Y., United States of America
- Center for Research in Infectious Diseases (CIENI), Instituto Nacional de Enfermedades Respiratorias, Mexico City, Mexico
| | - Aarón Lecanda-Sánchez
- Center for Research in Infectious Diseases (CIENI), Instituto Nacional de Enfermedades Respiratorias, Mexico City, Mexico
| | - Marcos Pérez-Losada
- Computational Biology Institute, Milken Institute School of Public Health, George Washington University, Washington, D.C., United States of America
- Department of Biostatistics and Bioinformatics, Milken Institute School of Public Health, George Washington University, Washington, D.C., United States of America
- CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, Vairão, Portugal
| | - Mario A. Ostrowski
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
- Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Toronto, Ontario, Canada
| | - R. Brad Jones
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, N.Y., United States of America
| | - Lubbertus C. F. Mulder
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- The Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Gustavo Reyes-Terán
- Center for Research in Infectious Diseases (CIENI), Instituto Nacional de Enfermedades Respiratorias, Mexico City, Mexico
| | - Keith A. Crandall
- Computational Biology Institute, Milken Institute School of Public Health, George Washington University, Washington, D.C., United States of America
- Department of Biostatistics and Bioinformatics, Milken Institute School of Public Health, George Washington University, Washington, D.C., United States of America
| | - Christopher E. Ormsby
- Center for Research in Infectious Diseases (CIENI), Instituto Nacional de Enfermedades Respiratorias, Mexico City, Mexico
| | - Douglas F. Nixon
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, N.Y., United States of America
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139
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Abstract
Transposable elements (TEs) are mobile DNA sequences that colonize genomes and threaten genome integrity. As a result, several mechanisms appear to have emerged during eukaryotic evolution to suppress TE activity. However, TEs are ubiquitous and account for a prominent fraction of most eukaryotic genomes. We argue that the evolutionary success of TEs cannot be explained solely by evasion from host control mechanisms. Rather, some TEs have evolved commensal and even mutualistic strategies that mitigate the cost of their propagation. These coevolutionary processes promote the emergence of complex cellular activities, which in turn pave the way for cooption of TE sequences for organismal function.
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Affiliation(s)
- Rachel L Cosby
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Ni-Chen Chang
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
| | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA
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140
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Endogenous Retrovirus-Derived Long Noncoding RNA Enhances Innate Immune Responses via Derepressing RELA Expression. mBio 2019; 10:mBio.00937-19. [PMID: 31363026 PMCID: PMC6667616 DOI: 10.1128/mbio.00937-19] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Endogenous retroviruses are transposable genetic elements comprising 8% to 10% of the human and mouse genomes. Although most ERVs have been inactivated due to deleterious mutations, some are still transcribed. However, the biological functions of transcribed ERVs are largely unknown. Here, we identified a full-length ERV-derived lncRNA, designated lnc-EPAV, as a positive regulator of host innate immune responses. We found that silencing lnc-EPAV impaired virus-induced cytokine production, resulting in increased viral replication in cells. The lnc-EPAV-deficient mice exhibited enhanced susceptibility to viral challenge. We also found that lnc-EPAV regulated expression of RELA, an NF-κB subunit that plays a critical role in antiviral responses. ERV-derived lncRNA coordinated with a transcription repressor, SFPQ, to control Rela transcription. Our report provides new insights into the previously unrecognized immune gene regulatory mechanism of ERV-derived lncRNAs. Endogenous retroviruses (ERVs) are transposable elements that cause host genome instability and usually play deleterious roles in disease such as tumorigenesis. Recent advances also suggest that this “enemy within” may encode a viral mimic to induce antiviral immune responses through viral sensors. Here, through whole-genome transcriptome analysis with RNA sequencing (RNA-Seq), we discovered that a full-length ERV-derived long noncoding RNA (lncRNA), designated lnc-EPAV (ERV-derived lncRNA positively regulates antiviral responses), was a positive regulator of NF-κB signaling. lnc-EPAV expression was rapidly upregulated by viral RNA mimics or RNA viruses to facilitate the expression of RELA, an NF-κB subunit that plays a crucial role in antiviral responses. Transcriptome analysis of lnc-EPAV-silenced macrophages showed that lnc-EPAV was critical for RELA target gene expression and innate immune responses. Consistently, lnc-EPAV-deficient mice exhibited reduced expression of type I interferons (IFNs) and, consequently, increased viral loads and mortality following lethal RNA virus infection. Mechanistically, lnc-EPAV promoted expression of RELA by competitively binding to and displacing SFPQ, a transcriptional repressor of Rela. Altogether, our work demonstrates an alternative mechanism by which ERVs regulate antiviral immune responses.
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141
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Gemmell P, Hein J, Katzourakis A. The Exaptation of HERV-H: Evolutionary Analyses Reveal the Genomic Features of Highly Transcribed Elements. Front Immunol 2019; 10:1339. [PMID: 31338090 PMCID: PMC6629862 DOI: 10.3389/fimmu.2019.01339] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 05/28/2019] [Indexed: 12/25/2022] Open
Abstract
HERV-H endogenous retroviruses are thought to be essential to stem cell identity in humans. We embrace several decades of HERV-H research in order to relate the transcription of HERV-H loci to their genomic structure. We find that highly transcribed HERV-H loci are younger, more fragmented, and less likely to be present in other primate genomes. We also show that repeats in HERV-H LTRs are correlated to where loci are transcribed: type-I LTRs associate with stem cells while type-II repeats associate with embryonic cells. Our findings are generally in line with what is known about endogenous retrovirus biology but we find that the presence of the zinc finger motif containing region of gag is positively correlated with transcription. This leads us to suggest a possible explanation for why an unusually large proportion of HERV-H loci have been preserved in non-solo-LTR form.
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Affiliation(s)
- Patrick Gemmell
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Jotun Hein
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Aris Katzourakis
- Department of Zoology, University of Oxford, Oxford, United Kingdom
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142
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Mareschi K, Montanari P, Rassu M, Galliano I, Daprà V, Adamini A, Castiglia S, Fagioli F, Bergallo M. Human Endogenous Retrovirus-H and K Expression in Human Mesenchymal Stem Cells as Potential Markers of Stemness. Intervirology 2019; 62:9-14. [PMID: 31104062 DOI: 10.1159/000499185] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 02/17/2019] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE The human endogenous retroviruses (HERVs) are endogenous retroviruses that were inserted into the germ cell DNA of humans over 30 million years ago. Insertion of HERVs into the chromosomal DNA can influence a number of host genes in various modes during human evolution and their proviral long terminal repeats can participate in the transcriptional regulation of various cellular genes. Our aim was to evaluate the pol gene expression of HERV-K and HERV-H in mesenchymal stem cells (MSCs) in relation with the expression of stemness genes such as NANOG, OCT-4, and SOX-2. METHODS MSCs were isolated from bone marrow of healthy donors and expanded until the 5th passage in α-MEM with 10% fetal bovine serum. HERV-K, HERV-H pol gene, NANOG, OCT-4, SOX-2, and GAPDH expression was quantified by real-time PCR in MSCs during the expansion. RESULTS HERV-K and HERV-H expression was always higher at p1 compared to other passages and this difference reached a high statistical significance when passage p1 was compared with passage 3. In addition, NANOG, OCT-4, and SOX-2 expression at p1 was significantly higher than their expression at p3. Pearson's test demonstrated a strong correlation between the expression of HERV-K and HERV-H and the expression of NANOG, OCT-4, and SOX-2. CONCLUSIONS Our findings showed that HERV-K and H were concurrently expressed with pluripotency biomarkers NANOG, OCT-4, and SOX-2.
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Affiliation(s)
- Katia Mareschi
- Department of Public Health and Pediatric Sciences, Medical School, University of Turin, Turin, Italy.,Pediatric Onco-Hematology, Stem Cell Transplantation and Cell Therapy Division, City of Science and Health of Turin, Regina Margherita Children Hospital, Turin, Italy
| | - Paola Montanari
- Department of Public Health and Pediatric Sciences, Medical School, University of Turin, Turin, Italy
| | - Marco Rassu
- Department of Public Health and Pediatric Sciences, Medical School, University of Turin, Turin, Italy
| | - Ilaria Galliano
- Department of Public Health and Pediatric Sciences, Medical School, University of Turin, Turin, Italy
| | - Valentina Daprà
- Department of Public Health and Pediatric Sciences, Medical School, University of Turin, Turin, Italy
| | - Aloe Adamini
- Pediatric Onco-Hematology, Stem Cell Transplantation and Cell Therapy Division, City of Science and Health of Turin, Regina Margherita Children Hospital, Turin, Italy
| | - Sara Castiglia
- Pediatric Onco-Hematology, Stem Cell Transplantation and Cell Therapy Division, City of Science and Health of Turin, Regina Margherita Children Hospital, Turin, Italy
| | - Franca Fagioli
- Pediatric Onco-Hematology, Stem Cell Transplantation and Cell Therapy Division, City of Science and Health of Turin, Regina Margherita Children Hospital, Turin, Italy
| | - Massimiliano Bergallo
- Department of Public Health and Pediatric Sciences, Medical School, University of Turin, Turin, Italy,
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143
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Krug B, De Jay N, Harutyunyan AS, Deshmukh S, Marchione DM, Guilhamon P, Bertrand KC, Mikael LG, McConechy MK, Chen CCL, Khazaei S, Koncar RF, Agnihotri S, Faury D, Ellezam B, Weil AG, Ursini-Siegel J, De Carvalho DD, Dirks PB, Lewis PW, Salomoni P, Lupien M, Arrowsmith C, Lasko PF, Garcia BA, Kleinman CL, Jabado N, Mack SC. Pervasive H3K27 Acetylation Leads to ERV Expression and a Therapeutic Vulnerability in H3K27M Gliomas. Cancer Cell 2019; 35:782-797.e8. [PMID: 31085178 PMCID: PMC6521975 DOI: 10.1016/j.ccell.2019.04.004] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/16/2019] [Accepted: 04/12/2019] [Indexed: 01/02/2023]
Abstract
High-grade gliomas defined by histone 3 K27M driver mutations exhibit global loss of H3K27 trimethylation and reciprocal gain of H3K27 acetylation, respectively shaping repressive and active chromatin landscapes. We generated tumor-derived isogenic models bearing this mutation and show that it leads to pervasive H3K27ac deposition across the genome. In turn, active enhancers and promoters are not created de novo and instead reflect the epigenomic landscape of the cell of origin. H3K27ac is enriched at repeat elements, resulting in their increased expression, which in turn can be further amplified by DNA demethylation and histone deacetylase inhibitors providing an exquisite therapeutic vulnerability. These agents may therefore modulate anti-tumor immune responses as a therapeutic modality for this untreatable disease.
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Affiliation(s)
- Brian Krug
- Department of Human Genetics, McGill University, Montreal, QC H3A 1B1, Canada
| | - Nicolas De Jay
- Department of Human Genetics, McGill University, Montreal, QC H3A 1B1, Canada; Lady Davis Research Institute, Jewish General Hospital, Montreal, QC H3T 1E2, Canada
| | - Ashot S Harutyunyan
- Department of Human Genetics, McGill University, Montreal, QC H3A 1B1, Canada
| | - Shriya Deshmukh
- Department of Human Genetics, McGill University, Montreal, QC H3A 1B1, Canada
| | - Dylan M Marchione
- Department of Biochemistry and Biophysics, and Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Paul Guilhamon
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5S 1A8, Canada; Ontario Institute for Cancer Research, Toronto, ON M5G 0A3, Canada
| | - Kelsey C Bertrand
- Department of Pediatrics, Division of Hematology and Oncology, Texas Children's Cancer and Hematology Centers, Dan L Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Leonie G Mikael
- Department of Pediatrics, McGill University, The Research Institute of the McGill University Health Center, Montreal, QC H4A 3J1, Canada
| | - Melissa K McConechy
- Department of Human Genetics, McGill University, Montreal, QC H3A 1B1, Canada
| | - Carol C L Chen
- Department of Human Genetics, McGill University, Montreal, QC H3A 1B1, Canada
| | - Sima Khazaei
- Department of Human Genetics, McGill University, Montreal, QC H3A 1B1, Canada
| | - Robert F Koncar
- Department of Neurological Surgery, Children's Hospital, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, USA
| | - Sameer Agnihotri
- Department of Neurological Surgery, Children's Hospital, University of Pittsburgh School of Medicine, Pittsburgh, PA 15232, USA
| | - Damien Faury
- Department of Pediatrics, McGill University, The Research Institute of the McGill University Health Center, Montreal, QC H4A 3J1, Canada
| | - Benjamin Ellezam
- Department of Pathology, Centre Hospitalier Universitaire Sainte-Justine, Université de Montréal, Montréal, QC H3T 1C5, Canada
| | - Alexander G Weil
- Department of Pediatric Neurosurgery, Centre Hospitalier Universitaire Sainte-Justine, Université de Montréal, Montréal, QC H3T 1C5, Canada
| | - Josie Ursini-Siegel
- Lady Davis Research Institute, Jewish General Hospital, Montreal, QC H3T 1E2, Canada
| | - Daniel D De Carvalho
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Peter B Dirks
- Department of Surgery and Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Peter W Lewis
- Department of Biomolecular Chemistry, School of Medicine and Public Health and Wisconsin Institute for Discovery, University of Wisconsin, Madison, WI 53715, USA
| | - Paolo Salomoni
- Nuclear Function in CNS Pathophysiology, German Center for Neurodegenerative Diseases, 53127 Bonn, Germany
| | - Mathieu Lupien
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5S 1A8, Canada; Ontario Institute for Cancer Research, Toronto, ON M5G 0A3, Canada
| | - Cheryl Arrowsmith
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Paul F Lasko
- Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada
| | - Benjamin A Garcia
- Department of Biochemistry and Biophysics, and Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Claudia L Kleinman
- Department of Human Genetics, McGill University, Montreal, QC H3A 1B1, Canada; Lady Davis Research Institute, Jewish General Hospital, Montreal, QC H3T 1E2, Canada.
| | - Nada Jabado
- Department of Human Genetics, McGill University, Montreal, QC H3A 1B1, Canada; Department of Pediatrics, McGill University, The Research Institute of the McGill University Health Center, Montreal, QC H4A 3J1, Canada.
| | - Stephen C Mack
- Department of Pediatrics, Division of Hematology and Oncology, Texas Children's Cancer and Hematology Centers, Dan L Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA.
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144
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Glinsky G, Barakat TS. The evolution of Great Apes has shaped the functional enhancers' landscape in human embryonic stem cells. Stem Cell Res 2019; 37:101456. [PMID: 31100635 DOI: 10.1016/j.scr.2019.101456] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 04/23/2019] [Accepted: 04/30/2019] [Indexed: 12/21/2022] Open
Abstract
High-throughput functional assays of enhancer activity have recently enabled the genome-scale definition of molecular, structural, and biochemical features of these genomic regulatory regions. To infer the evolutionary origin of DNA sequences operating as functional enhancers in human embryonic stem cells (hESC), we examined the patterns of evolutionary conservation and divergence in the genome-wide functional enhancers' landscape of hESC. We show that a prominent majority (up to 94%) of DNA sequences identified in hESC as functional enhancers are conserved in humans and our closest evolutionary relatives, Chimpanzee and Bonobo. More than 91% of functional enhancers that are highly conserved in both Chimpanzee and Bonobo, are conserved among other Great Apes and >75% are conserved in the Rhesus genome. In striking contrast, <5% of DNA sequences operating in hESC as functional enhancers are conserved in rodents. Conserved in primates enhancers' sequences are complemented by 1619 sequences of enhancers that are specific to humans. Enhancers that harbor human-specific sequences appear enriched among the invariant enhancer module maintaining activity in different pluripotent states and these regions are associated with pluripotency- and embryonic-lineage-related genes. However, functional enhancers make up only a minority of all conserved in primates or human-specific transcription factor binding sites. Our analyses revealed that sequences that are conserved during ~8 million years of primate evolution dominate the genomic landscape of functional enhancers in both primed and naïve hESC. Collectively, these observations revealed thousands of evolutionarily conserved sequences that function as a core regulatory network in human embryonic stem cells which has recently undergone further extension after divergence of modern humans from our closest relatives, Chimpanzee and Bonobo.
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Affiliation(s)
- Gennadi Glinsky
- Institute of Engineering in Medicine, University of California San Diego, 9500 Gilman Dr. MC 0435, La Jolla, CA 92093-0435, USA.
| | - Tahsin Stefan Barakat
- Department of Clinical Genetics, Erasmus MC, University Medical Center, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
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145
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Pontis J, Planet E, Offner S, Turelli P, Duc J, Coudray A, Theunissen TW, Jaenisch R, Trono D. Hominoid-Specific Transposable Elements and KZFPs Facilitate Human Embryonic Genome Activation and Control Transcription in Naive Human ESCs. Cell Stem Cell 2019; 24:724-735.e5. [PMID: 31006620 PMCID: PMC6509360 DOI: 10.1016/j.stem.2019.03.012] [Citation(s) in RCA: 152] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/04/2019] [Accepted: 03/12/2019] [Indexed: 11/17/2022]
Abstract
Expansion of transposable elements (TEs) coincides with evolutionary shifts in gene expression. TEs frequently harbor binding sites for transcriptional regulators, thus enabling coordinated genome-wide activation of species- and context-specific gene expression programs, but such regulation must be balanced against their genotoxic potential. Here, we show that Krüppel-associated box (KRAB)-containing zinc finger proteins (KZFPs) control the timely and pleiotropic activation of TE-derived transcriptional cis regulators during early embryogenesis. Evolutionarily recent SVA, HERVK, and HERVH TE subgroups contribute significantly to chromatin opening during human embryonic genome activation and are KLF-stimulated enhancers in naive human embryonic stem cells (hESCs). KZFPs of corresponding evolutionary ages are simultaneously induced and repress the transcriptional activity of these TEs. Finally, the same KZFP-controlled TE-based enhancers later serve as developmental and tissue-specific enhancers. Thus, by controlling the transcriptional impact of TEs during embryogenesis, KZFPs facilitate their genome-wide incorporation into transcriptional networks, thereby contributing to human genome regulation. KLFs foster EGA by activating enhancers embedded in young TEs (TEENhancers) TEENhancers confer a degree of species specificity to early genome activation TEENhancers stimulate the expression of KZFPs responsible for their repression These KZFPs in turn facilitate TEENhancers’ exaptation as tissue-specific regulators
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Affiliation(s)
- Julien Pontis
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Evarist Planet
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Sandra Offner
- 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
| | - Julien Duc
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Alexandre Coudray
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Thorold W Theunissen
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA
| | - Rudolf Jaenisch
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA
| | - Didier Trono
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
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146
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Shapiro JA. No genome is an island: toward a 21st century agenda for evolution. Ann N Y Acad Sci 2019; 1447:21-52. [DOI: 10.1111/nyas.14044] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/17/2019] [Accepted: 02/02/2019] [Indexed: 12/21/2022]
Affiliation(s)
- James A. Shapiro
- Department of Biochemistry and Molecular BiologyUniversity of Chicago Chicago Illinois
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147
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Nguyen TD, Davis J, Eugenio RA, Liu Y. Female Sex Hormones Activate Human Endogenous Retrovirus Type K Through the OCT4 Transcription Factor in T47D Breast Cancer Cells. AIDS Res Hum Retroviruses 2019; 35:348-356. [PMID: 30565469 DOI: 10.1089/aid.2018.0173] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Female sex hormones, the octamer-binding transcription factor 4 (OCT4), and human endogenous retroviruses (HERVs) are all involved in the development of breast cancer. However, whether there are cross talks between these factors to promote breast cancer is still unknown. Using the T47D human breast cancer cell line, we have found that estradiol and progesterone synergistically activate HERV-K through nuclear receptors. The progesterone receptor (isoform B) binds a progesterone-response element (PRE) in a long terminal repeat (LTR5HS) of HERV-K. There is another transcription factor-binding element in the LTR, the octamer motif, which is required for the hormones to activate gene transcription downstream of the LTR. Gel shift assays and co-immunoprecipitation indicate that the progesterone receptor (PR) and the OCT4 transcription factor interact on the protein level. Methylation of the PRE enhances binding of the PR. These findings help to elucidate the previously unknown cross talks among the sex hormones, OCT4, and HERVs in contributing to breast cancer proliferation and tumorigenesis, which may be useful in guiding further development of cancer therapies.
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Affiliation(s)
- Tam D. Nguyen
- Department of Molecular and Cellular Sciences, Liberty University College of Osteopathic Medicine, Lynchburg, Virginia
| | - James Davis
- Department of Molecular and Cellular Sciences, Liberty University College of Osteopathic Medicine, Lynchburg, Virginia
| | - Roelle A. Eugenio
- Department of Molecular and Cellular Sciences, Liberty University College of Osteopathic Medicine, Lynchburg, Virginia
| | - Yingguang Liu
- Department of Molecular and Cellular Sciences, Liberty University College of Osteopathic Medicine, Lynchburg, Virginia
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Fu B, Ma H, Liu D. Endogenous Retroviruses Function as Gene Expression Regulatory Elements During Mammalian Pre-implantation Embryo Development. Int J Mol Sci 2019; 20:ijms20030790. [PMID: 30759824 PMCID: PMC6387303 DOI: 10.3390/ijms20030790] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 02/05/2019] [Accepted: 02/05/2019] [Indexed: 01/13/2023] Open
Abstract
Pre-implantation embryo development encompasses several key developmental events, especially the activation of zygotic genome activation (ZGA)-related genes. Endogenous retroviruses (ERVs), which are regarded as “deleterious genomic parasites”, were previously considered to be “junk DNA”. However, it is now known that ERVs, with limited conservatism across species, mediate conserved developmental processes (e.g., ZGA). Transcriptional activation of ERVs occurs during the transition from maternal control to zygotic genome control, signifying ZGA. ERVs are versatile participants in rewiring gene expression networks during epigenetic reprogramming. Particularly, a subtle balance exists between ERV activation and ERV repression in host–virus interplay, which leads to stage-specific ERV expression during pre-implantation embryo development. A large portion of somatic cell nuclear transfer (SCNT) embryos display developmental arrest and ZGA failure during pre-implantation embryo development. Furthermore, because of the close relationship between ERV activation and ZGA, exploring the regulatory mechanism underlying ERV activation may also shed more light on the enigma of SCNT embryo development in model animals.
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Affiliation(s)
- Bo Fu
- Institute of Animal Husbandry Research, HeiLongJiang Academy of Agricultural Sciences, Harbin 150086, China.
- Key Laboratory of Combine of Planting and Feeding, Ministry of Agriculture of the People's Republic of China, Harbin 150086, China.
| | - Hong Ma
- Institute of Animal Husbandry Research, HeiLongJiang Academy of Agricultural Sciences, Harbin 150086, China.
- Key Laboratory of Combine of Planting and Feeding, Ministry of Agriculture of the People's Republic of China, Harbin 150086, China.
| | - Di Liu
- Institute of Animal Husbandry Research, HeiLongJiang Academy of Agricultural Sciences, Harbin 150086, China.
- Key Laboratory of Combine of Planting and Feeding, Ministry of Agriculture of the People's Republic of China, Harbin 150086, China.
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149
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The Histone Methyltransferase SETDB1 Controls T Helper Cell Lineage Integrity by Repressing Endogenous Retroviruses. Immunity 2019; 50:629-644.e8. [PMID: 30737147 DOI: 10.1016/j.immuni.2019.01.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 10/02/2018] [Accepted: 01/04/2019] [Indexed: 02/07/2023]
Abstract
Upon activation, naive CD4+ T cells differentiate into distinct T cell subsets via processes reliant on epigenetically regulated, lineage-specific developmental programs. Here, we examined the function of the histone methyltransferase SETDB1 in T helper (Th) cell differentiation. Setdb1-/- naive CD4+ T cells exhibited exacerbated Th1 priming, and when exposed to a Th1-instructive signal, Setdb1-/- Th2 cells crossed lineage boundaries and acquired a Th1 phenotype. SETDB1 did not directly control Th1 gene promoter activity but relied instead on deposition of the repressive H3K9me3 mark at a restricted and cell-type-specific set of endogenous retroviruses (ERVs) located in the vicinity of genes involved in immune processes. Refined bioinformatic analyses suggest that these retrotransposons regulate Th1 gene cis-regulatory elements or act as Th1 gene enhancers. Thus, H3K9me3 deposition by SETDB1 ensures Th cell lineage integrity by repressing a repertoire of ERVs that have been exapted into cis-regulatory modules to shape and control the Th1 gene network.
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150
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Transposable elements are regulated by context-specific patterns of chromatin marks in mouse embryonic stem cells. Nat Commun 2019; 10:34. [PMID: 30604769 PMCID: PMC6318327 DOI: 10.1038/s41467-018-08006-y] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 12/11/2018] [Indexed: 01/18/2023] Open
Abstract
The majority of mammalian genomes are devoted to transposable elements (TEs). Whilst TEs are increasingly recognized for their important biological functions, they are a potential danger to genomic stability and are carefully regulated by the epigenetic system. However, the full complexity of this regulatory system is not understood. Here, using mouse embryonic stem cells, we show that TEs are suppressed by heterochromatic marks like H3K9me3, and are also labelled by all major types of chromatin modification in complex patterns, including bivalent activatory and repressive marks. We identified 29 epigenetic modifiers that significantly deregulated at least one type of TE. The loss of Setdb1, Ncor2, Rnf2, Kat5, Prmt5, Uhrf1, and Rrp8 caused widespread changes in TE expression and chromatin accessibility. These effects were context-specific, with different chromatin modifiers regulating the expression and chromatin accessibility of specific subsets of TEs. Our work reveals the complex patterns of epigenetic regulation of TEs. Transposable elements (TEs) fulfill essential but poorly understood roles in genome organization and gene expression control. Here the authors show that the regulation of TEs occurs through overlapping epigenetic mechanisms that control the expression and chromatin signatures at TEs.
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