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Cantarella S, Vezzoli M, Carnevali D, Morselli M, Zemke NR, Montanini B, Daussy CF, Wodrich H, Teichmann M, Pellegrini M, Berk AJ, Dieci G, Ferrari R. Adenovirus small E1A directs activation of Alu transcription at YAP/TEAD- and AP-1-bound enhancers through interactions with the EP400 chromatin remodeler. Nucleic Acids Res 2024:gkae615. [PMID: 39011896 DOI: 10.1093/nar/gkae615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 04/29/2024] [Accepted: 07/02/2024] [Indexed: 07/17/2024] Open
Abstract
Alu retrotransposons, which form the largest family of mobile DNA elements in the human genome, have recently come to attention as a potential source of regulatory novelties, most notably by participating in enhancer function. Even though Alu transcription by RNA polymerase III is subjected to tight epigenetic silencing, their expression has long been known to increase in response to various types of stress, including viral infection. Here we show that, in primary human fibroblasts, adenovirus small e1a triggered derepression of hundreds of individual Alus by promoting TFIIIB recruitment by Alu-bound TFIIIC. Epigenome profiling revealed an e1a-induced decrease of H3K27 acetylation and increase of H3K4 monomethylation at derepressed Alus, making them resemble poised enhancers. The enhancer nature of e1a-targeted Alus was confirmed by the enrichment, in their upstream regions, of the EP300/CBP acetyltransferase, EP400 chromatin remodeler and YAP1 and FOS transcription factors. The physical interaction of e1a with EP400 was critical for Alu derepression, which was abrogated upon EP400 ablation. Our data suggest that e1a targets a subset of enhancer Alus whose transcriptional activation, which requires EP400 and is mediated by the e1a-EP400 interaction, may participate in the manipulation of enhancer activity by adenoviruses.
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Affiliation(s)
- Simona Cantarella
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy
| | - Marco Vezzoli
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy
| | - Davide Carnevali
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy
| | - Marco Morselli
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy
| | - Nathan R Zemke
- Molecular Biology Institute, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Barbara Montanini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy
| | - Coralie F Daussy
- Bordeaux University, CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, Bordeaux, France
| | - Harald Wodrich
- Bordeaux University, CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, Bordeaux, France
| | - Martin Teichmann
- Bordeaux University, Inserm U 1312, Bordeaux Institute of Oncology, 33076 Bordeaux, France
| | - Matteo Pellegrini
- Department of Molecular Cellular and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Arnold J Berk
- Molecular Biology Institute, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Giorgio Dieci
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy
| | - Roberto Ferrari
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy
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2
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Kawase M, Ichiyanagi K. Mouse retrotransposons: sequence structure, evolutionary age, genomic distribution and function. Genes Genet Syst 2024; 98:337-351. [PMID: 37989301 DOI: 10.1266/ggs.23-00221] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023] Open
Abstract
Retrotransposons are transposable elements that are transposed via transcription and reverse transcription. Their copies have accumulated in the genome of mammals, occupying approximately 40% of mammalian genomic mass. These copies are often involved in numerous phenomena, such as chromatin spatial organization, gene expression, development and disease, and have been recognized as a driving force in evolution. Different organisms have gained specific retrotransposon subfamilies and retrotransposed copies, such as hundreds of Mus-specific subfamilies with diverse sequences and genomic locations. Despite this complexity, basic information is still necessary for present-day genomic and epigenomic studies. Herein, we describe the characteristics of each subfamily of Mus-specific retrotransposons in terms of sequence structure, phylogenetic relationships, evolutionary age, and preference for A or B compartments of chromatin.
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Affiliation(s)
- Masaki Kawase
- Laboratory of Genome and Epigenome Dynamics, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University
| | - Kenji Ichiyanagi
- Laboratory of Genome and Epigenome Dynamics, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University
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3
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Zong W, Wang J, Zhao R, Niu N, Su Y, Hu Z, Liu X, Hou X, Wang L, Wang L, Zhang L. Associations of genome-wide structural variations with phenotypic differences in cross-bred Eurasian pigs. J Anim Sci Biotechnol 2023; 14:136. [PMID: 37805653 PMCID: PMC10559557 DOI: 10.1186/s40104-023-00929-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 08/03/2023] [Indexed: 10/09/2023] Open
Abstract
BACKGROUND During approximately 10,000 years of domestication and selection, a large number of structural variations (SVs) have emerged in the genome of pig breeds, profoundly influencing their phenotypes and the ability to adapt to the local environment. SVs (≥ 50 bp) are widely distributed in the genome, mainly in the form of insertion (INS), mobile element insertion (MEI), deletion (DEL), duplication (DUP), inversion (INV), and translocation (TRA). While studies have investigated the SVs in pig genomes, genome-wide association studies (GWAS)-based on SVs have been rarely conducted. RESULTS Here, we obtained a high-quality SV map containing 123,151 SVs from 15 Large White and 15 Min pigs through integrating the power of several SV tools, with 53.95% of the SVs being reported for the first time. These high-quality SVs were used to recover the population genetic structure, confirming the accuracy of genotyping. Potential functional SV loci were then identified based on positional effects and breed stratification. Finally, GWAS were performed for 36 traits by genotyping the screened potential causal loci in the F2 population according to their corresponding genomic positions. We identified a large number of loci involved in 8 carcass traits and 6 skeletal traits on chromosome 7, with FKBP5 containing the most significant SV locus for almost all traits. In addition, we found several significant loci in intramuscular fat, abdominal circumference, heart weight, and liver weight, etc. CONCLUSIONS: We constructed a high-quality SV map using high-coverage sequencing data and then analyzed them by performing GWAS for 25 carcass traits, 7 skeletal traits, and 4 meat quality traits to determine that SVs may affect body size between European and Chinese pig breeds.
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Affiliation(s)
- Wencheng Zong
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Jinbu Wang
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Runze Zhao
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- College of Animal Science, Shanxi Agricultural University, Jinzhong, 030801, China
| | - Naiqi Niu
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Yanfang Su
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Ziping Hu
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, 266109, China
| | - Xin Liu
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Xinhua Hou
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Ligang Wang
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Lixian Wang
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
| | - Longchao Zhang
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
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4
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Sharif J, Koseki H, Parrish NF. Bridging multiple dimensions: roles of transposable elements in higher-order genome regulation. Curr Opin Genet Dev 2023; 80:102035. [PMID: 37028152 DOI: 10.1016/j.gde.2023.102035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/01/2023] [Accepted: 03/05/2023] [Indexed: 04/09/2023]
Abstract
Transposable elements (TEs) such as endogenous retroviruses (ERVs), long interspersed nuclear elements (LINEs), and short interspersed nuclear elements (SINEs) occupy nearly half of typical mammalian genomes. Previous studies show that these parasitic elements, especially LINEs and ERVs, provide important activities promoting host germ cell and placental development, preimplantation embryogenesis, and maintenance of pluripotent stem cells. Despite being the most numerically abundant type of TEs in the genome, the consequences of SINEs on host genome regulation are less well characterized than those of ERVs and LINEs. Interestingly, recent findings reveal that SINEs recruit the key architectural protein CTCF (CCCTC-binding factor), indicating a role of these elements for 3D genome regulation. Higher-order nuclear structures are linked with important cellular functions such as gene regulation and DNA replication. SINEs and other TEs, therefore, may mediate distinct physiological processes with benefits to the host by modulating the 3D genome.
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Affiliation(s)
- Jafar Sharif
- Laboratory of Developmental Genetics, RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
| | - Haruhiko Koseki
- Laboratory of Developmental Genetics, RIKEN Center for Integrative Medical Sciences, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan; Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan
| | - Nicholas F Parrish
- Genome Immunobiology RIKEN Hakubi Research Team, RIKEN Center for Integrative Medical Sciences and RIKEN Cluster for Pioneering Research, Yokohama, Japan.
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5
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Lari A, Glaunsinger BA. Murine Gammaherpesvirus 68 ORF45 Stimulates B2 Retrotransposon and Pre-tRNA Activation in a Manner Dependent on Mitogen-Activated Protein Kinase (MAPK) Signaling. Microbiol Spectr 2023; 11:e0017223. [PMID: 36752632 PMCID: PMC10100704 DOI: 10.1128/spectrum.00172-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 01/21/2023] [Indexed: 02/09/2023] Open
Abstract
RNA polymerase III (RNAPIII) transcribes a variety of noncoding RNAs, including tRNA (tRNA) and the B2 family of short interspersed nuclear elements (SINEs). B2 SINEs are noncoding retrotransposons that possess tRNA-like promoters and are normally silenced in healthy somatic tissue. Infection with the murine gammaherpesvirus MHV68 induces transcription of both SINEs and tRNAs, in part through the activity of the viral protein kinase ORF36. Here, we identify the conserved MHV68 tegument protein ORF45 as an additional activator of these RNAPIII loci. MHV68 ORF45 and ORF36 form a complex, resulting in an additive induction RNAPIII and increased ORF45 expression. ORF45-induced RNAPIII transcription is dependent on its activation of the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) signaling pathway, which in turn increases the abundance of the RNAPIII transcription factor Brf1. Other viral and nonviral activators of MAPK/ERK signaling also increase the levels of Brf1 protein, B2 SINE RNA, and tRNA, suggesting that this is a common strategy to increase RNAPIII activity. IMPORTANCE Gammaherpesviral infection alters the gene expression landscape of a host cell, including through the induction of noncoding RNAs transcribed by RNA polymerase III (RNAPIII). Among these are a class of repetitive genes known as retrotransposons, which are normally silenced elements and can copy and spread throughout the genome, and transfer RNAs (tRNAs), which are fundamental components of protein translation machinery. How these loci are activated during infection is not well understood. Here, we identify ORF45 from the model murine gammaherpesvirus MHV68 as a novel activator of RNAPIII transcription. To do so, it engages the MAPK/ERK signaling pathway, which is a central regulator of cellular response to environmental stimuli. Activation of this pathway leads to the upregulation of a key factor required for RNAPIII activity, Brf1. These findings expand our understanding of the regulation and dysregulation of RNAPIII transcription and highlight how viral cooption of key signaling pathways can impact host gene expression.
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Affiliation(s)
- Azra Lari
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Britt A. Glaunsinger
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
- Howard Hughes Medical Institute, Berkeley, California, USA
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6
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From Nucleus to Organs: Insights of Aryl Hydrocarbon Receptor Molecular Mechanisms. Int J Mol Sci 2022; 23:ijms232314919. [PMID: 36499247 PMCID: PMC9738205 DOI: 10.3390/ijms232314919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 11/30/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a markedly established regulator of a plethora of cellular and molecular processes. Its initial role in the detoxification of xenobiotic compounds has been partially overshadowed by its involvement in homeostatic and organ physiology processes. In fact, the discovery of its ability to bind specific target regulatory sequences has allowed for the understanding of how AHR modulates such processes. Thereby, AHR presents functions in transcriptional regulation, chromatin architecture modifications and participation in different key signaling pathways. Interestingly, such fields of influence end up affecting organ and tissue homeostasis, including regenerative response both to endogenous and exogenous stimuli. Therefore, from classical spheres such as canonical transcriptional regulation in embryonic development, cell migration, differentiation or tumor progression to modern approaches in epigenetics, senescence, immune system or microbiome, this review covers all aspects derived from the balance between regulation/deregulation of AHR and its physio-pathological consequences.
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7
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Sizer RE, Chahid N, Butterfield SP, Donze D, Bryant NJ, White RJ. TFIIIC-based chromatin insulators through eukaryotic evolution. Gene X 2022; 835:146533. [PMID: 35623477 DOI: 10.1016/j.gene.2022.146533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 04/19/2022] [Accepted: 04/29/2022] [Indexed: 11/04/2022] Open
Abstract
Eukaryotic chromosomes are divided into domains with distinct structural and functional properties, such as differing levels of chromatin compaction and gene transcription. Domains of relatively compact chromatin and minimal transcription are termed heterochromatic, whereas euchromatin is more open and actively transcribed. Insulators separate these domains and maintain their distinct features. Disruption of insulators can cause diseases such as cancer. Many insulators contain tRNA genes (tDNAs), examples of which have been shown to block the spread of activating or silencing activities. This characteristic of specific tDNAs is conserved through evolution, such that human tDNAs can serve as barriers to the spread of silencing in fission yeast. Here we demonstrate that tDNAs from the methylotrophic fungus Pichia pastoris can function effectively as insulators in distantly-related budding yeast. Key to the function of tDNAs as insulators is TFIIIC, a transcription factor that is also required for their expression. TFIIIC binds additional loci besides tDNAs, some of which have insulator activity. Although the mechanistic basis of TFIIIC-based insulation has been studied extensively in yeast, it is largely uncharacterized in metazoa. Utilising publicly-available genome-wide ChIP-seq data, we consider the extent to which mechanisms conserved from yeast to man may suffice to allow efficient insulation by TFIIIC in the more challenging chromatin environments of metazoa and suggest features that may have been acquired during evolution to cope with new challenges. We demonstrate the widespread presence at human tDNAs of USF1, a transcription factor with well-established barrier activity in vertebrates. We predict that tDNA-based insulators in higher organisms have evolved through incorporation of modules, such as binding sites for factors like USF1 and CTCF that are absent from yeasts, thereby strengthening function and providing opportunities for regulation between cell types.
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Affiliation(s)
- Rebecca E Sizer
- Department of Biology, The University of York, York YO10 5DD, UK
| | - Nisreen Chahid
- Department of Biology, The University of York, York YO10 5DD, UK
| | | | - David Donze
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Nia J Bryant
- Department of Biology, The University of York, York YO10 5DD, UK
| | - Robert J White
- Department of Biology, The University of York, York YO10 5DD, UK.
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8
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The Role of Transposable Elements of the Human Genome in Neuronal Function and Pathology. Int J Mol Sci 2022; 23:ijms23105847. [PMID: 35628657 PMCID: PMC9148063 DOI: 10.3390/ijms23105847] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 12/13/2022] Open
Abstract
Transposable elements (TEs) have been extensively studied for decades. In recent years, the introduction of whole-genome and whole-transcriptome approaches, as well as single-cell resolution techniques, provided a breakthrough that uncovered TE involvement in host gene expression regulation underlying multiple normal and pathological processes. Of particular interest is increased TE activity in neuronal tissue, and specifically in the hippocampus, that was repeatedly demonstrated in multiple experiments. On the other hand, numerous neuropathologies are associated with TE dysregulation. Here, we provide a comprehensive review of literature about the role of TEs in neurons published over the last three decades. The first chapter of the present review describes known mechanisms of TE interaction with host genomes in general, with the focus on mammalian and human TEs; the second chapter provides examples of TE exaptation in normal neuronal tissue, including TE involvement in neuronal differentiation and plasticity; and the last chapter lists TE-related neuropathologies. We sought to provide specific molecular mechanisms of TE involvement in neuron-specific processes whenever possible; however, in many cases, only phenomenological reports were available. This underscores the importance of further studies in this area.
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9
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Rejano-Gordillo C, Ordiales-Talavero A, Nacarino-Palma A, Merino JM, González-Rico FJ, Fernández-Salguero PM. Aryl Hydrocarbon Receptor: From Homeostasis to Tumor Progression. Front Cell Dev Biol 2022; 10:884004. [PMID: 35465323 PMCID: PMC9022225 DOI: 10.3389/fcell.2022.884004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 03/15/2022] [Indexed: 12/19/2022] Open
Abstract
Transcription factor aryl hydrocarbon receptor (AHR) has emerged as one of the main regulators involved both in different homeostatic cell functions and tumor progression. Being a member of the family of basic-helix-loop-helix (bHLH) transcriptional regulators, this intracellular receptor has become a key member in differentiation, pluripotency, chromatin dynamics and cell reprogramming processes, with plenty of new targets identified in the last decade. Besides this role in tissue homeostasis, one enthralling feature of AHR is its capacity of acting as an oncogene or tumor suppressor depending on the specific organ, tissue and cell type. Together with its well-known modulation of cell adhesion and migration in a cell-type specific manner in epithelial-mesenchymal transition (EMT), this duality has also contributed to the arise of its clinical interest, highlighting a new potential as therapeutic tool, diagnosis and prognosis marker. Therefore, a deregulation of AHR-controlled pathways may have a causal role in contributing to physiological and homeostatic failures, tumor progression and dissemination. With that firmly in mind, this review will address the remarkable capability of AHR to exert a different function influenced by the phenotype of the target cell and its potential consequences.
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Affiliation(s)
- Claudia Rejano-Gordillo
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Ana Ordiales-Talavero
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Ana Nacarino-Palma
- Chronic Diseases Research Centre (CEDOC), Rua Do Instituto Bacteriológico, Lisboa, Portugal
| | - Jaime M. Merino
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Francisco J. González-Rico
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
- *Correspondence: Francisco J. González-Rico, ; Pedro M. Fernández-Salguero,
| | - Pedro M. Fernández-Salguero
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
- *Correspondence: Francisco J. González-Rico, ; Pedro M. Fernández-Salguero,
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10
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Song Z, Shah S, Lv B, Ji N, Liu X, Yan L, Khan M, Zhao Y, Wu P, Liu S, Zheng L, Su L, Wang X, Lv Z. Anti-aging and anti-oxidant activities of murine short interspersed nuclear element antisense RNA. Eur J Pharmacol 2021; 912:174577. [PMID: 34688636 DOI: 10.1016/j.ejphar.2021.174577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 10/07/2021] [Accepted: 10/18/2021] [Indexed: 12/09/2022]
Abstract
Short interspersed nuclear elements (SINEs) play a key role in regulating gene expression, and SINE RNAs are involved in age-related diseases. We investigated the anti-aging effects of a genetically engineered murine SINE B1 antisense RNA (B1as RNA) and explored its mechanism of action in naturally senescent BALB/c (≥14 months) and moderately senscent C57BL/6N (≥9 months) mice. After tail vein injection, B1as RNA was available in the blood of mice for approximately 30 min, persisted for approximately 2-4 h in most detected tissues and persisted approximately 48 h in lungs. We found that treatment with B1as RNA improved stamina and promoted hair re-growth in aged mice. Treatment with B1as RNA also partially rescued the increase in mitochondrial DNA copy number in liver and spleen tissues observed in aged and moderately senescent mice. Finally, treatment with B1as RNA increased the activities of superoxide dismutase and glutathione peroxidase in aged and moderately senescent mice, reduced these animals' malondialdehyde and reactive oxygen species levels, and modulated the expression of several aging-associated genes, including Sirtuin 1, p21, p16Ink4a, p15Ink4b and p19Arf, and anti-oxidant genes (Sesn1 and Sesn 2). These data suggest that B1as RNA inhibits the aging process by enhancing antioxidant activity, promoting the scavenging of free radicals, and modulating the expression of aging-associated genes. This is the first report describing the anti-aging activity of SINE antisense RNA, which may serve as an effective nucleic acid drug for the treatment of age-related diseases.
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Affiliation(s)
- Zhixue Song
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, PR China.
| | - Suleman Shah
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, PR China.
| | - Baixue Lv
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, Hubei Province, PR China; Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, Hubei Province, PR China.
| | - Ning Ji
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, PR China.
| | - Xin Liu
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, PR China.
| | - Lifang Yan
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, PR China.
| | - Murad Khan
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, PR China.
| | - Yufang Zhao
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, PR China.
| | - Peiyuan Wu
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, PR China.
| | - Shufeng Liu
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, PR China.
| | - Long Zheng
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, PR China.
| | - Libo Su
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, PR China.
| | - Xiufang Wang
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, PR China.
| | - Zhanjun Lv
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, PR China.
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11
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A hypothetical model of trans-acting R-loops-mediated promoter-enhancer interactions by Alu elements. J Genet Genomics 2021; 48:1007-1019. [PMID: 34531149 DOI: 10.1016/j.jgg.2021.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/24/2021] [Accepted: 07/07/2021] [Indexed: 12/22/2022]
Abstract
Enhancers modulate gene expression by interacting with promoters. Models of enhancer-promoter interactions (EPIs) in the literature involve the activity of many components, including transcription factors and nucleic acid. However, the role that sequence similarity plays in EPIs remains largely unexplored. Herein, we report that Alu-derived sequences dominate sequence similarity between enhancers and promoters. After rejecting alternative DNA:DNA and DNA:RNA triplex models, we propose that enhancer-associated RNAs (eRNAs) may directly contact their targeted promoters by forming trans-acting R-loops at those Alu sequences. We show how the characteristic distribution of functional genomic data, such as RNA-DNA proximate ligation reads, binding of transcription factors, and RNA-binding proteins, all align with the Alu sequences of EPIs. We also show that these aligned Alu sequences may be subject to the constraint of coevolution, further implying the functional significance of these R-loop hybrids. Finally, our results imply that eRNA and Alu elements associate in a manner previously unrecognized in EPIs and the evolution of gene regulation networks in mammals.
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12
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Ichiyanagi T, Katoh H, Mori Y, Hirafuku K, Boyboy BA, Kawase M, Ichiyanagi K. B2 SINE Copies Serve as a Transposable Boundary of DNA Methylation and Histone Modifications in the Mouse. Mol Biol Evol 2021; 38:2380-2395. [PMID: 33592095 PMCID: PMC8136502 DOI: 10.1093/molbev/msab033] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
More than one million copies of short interspersed elements (SINEs), a class of retrotransposons, are present in the mammalian genomes, particularly within gene-rich genomic regions. Evidence has accumulated that ancient SINE sequences have acquired new binding sites for transcription factors (TFs) through multiple mutations following retrotransposition, and as a result have rewired the host regulatory network during the course of evolution. However, it remains unclear whether currently active SINEs contribute to the expansion of TF binding sites. To study the mobility, expression, and function of SINE copies, we first identified about 2,000 insertional polymorphisms of SINE B1 and B2 families within Mus musculus. Using a novel RNA sequencing method designated as melRNA-seq, we detected the expression of SINEs in male germ cells at both the subfamily and genomic copy levels: the vast majority of B1 RNAs originated from evolutionarily young subfamilies, whereas B2 RNAs originated from both young and old subfamilies. DNA methylation and chromatin immunoprecipitation-sequencing (ChIP-seq) analyses in liver revealed that polymorphic B2 insertions served as a boundary element inhibiting the expansion of DNA hypomethylated and histone hyperacetylated regions, and decreased the expression of neighboring genes. Moreover, genomic B2 copies were enriched at the boundary of various histone modifications, and chromatin insulator protein, CCCTC-binding factor, a well-known chromatin boundary protein, bound to >100 polymorphic and >10,000 non-polymorphic B2 insertions. These results suggest that the currently active B2 copies are mobile boundary elements that can modulate chromatin modifications and gene expression, and are likely involved in epigenomic and phenotypic diversification of the mouse species.
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Affiliation(s)
- Tomoko Ichiyanagi
- Laboratory of Genome and Epigenome Dynamics, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Hirokazu Katoh
- Laboratory of Genome and Epigenome Dynamics, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Yoshinobu Mori
- Laboratory of Genome and Epigenome Dynamics, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Keigo Hirafuku
- The Jikei University Hospital, Minato-ku, Tokyo 105-8471, Japan
| | - Beverly Ann Boyboy
- Laboratory of Genome and Epigenome Dynamics, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Masaki Kawase
- Laboratory of Genome and Epigenome Dynamics, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Kenji Ichiyanagi
- Laboratory of Genome and Epigenome Dynamics, Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
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13
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Zablon HA, Ko CI, Puga A. Converging Roles of the Aryl Hydrocarbon Receptor in Early Embryonic Development, Maintenance of Stemness, and Tissue Repair. Toxicol Sci 2021; 182:1-9. [PMID: 34009372 PMCID: PMC8285021 DOI: 10.1093/toxsci/kfab050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor well-known for its adaptive role as a sensor of environmental toxicants and mediator of the metabolic detoxification of xenobiotic ligands. In addition, a growing body of experimental data has provided indisputable evidence that the AHR regulates critical functions of cell physiology and embryonic development. Recent studies have shown that the naïve AHR-that is, unliganded to xenobiotics but activated endogenously-has a crucial role in maintenance of embryonic stem cell pluripotency, tissue repair, and regulation of cancer stem cell stemness. Depending on the cellular context, AHR silences the expression of pluripotency genes Oct4 and Nanog and potentiates differentiation, whereas curtailing cellular plasticity and stemness. In these processes, AHR-mediated contextual responses and outcomes are dictated by changes of interacting partners in signaling pathways, gene networks, and cell-type-specific genomic structures. In this review, we focus on AHR-mediated changes of genomic architecture as an emerging mechanism for the AHR to regulate gene expression at the transcriptional level. Collective evidence places this receptor as a physiological hub connecting multiple biological processes whose disruption impacts on embryonic development, tissue repair, and maintenance or loss of stemness.
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Affiliation(s)
| | | | - Alvaro Puga
- Department of Environmental and Public Health Sciences, Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA
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14
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Etchegaray E, Naville M, Volff JN, Haftek-Terreau Z. Transposable element-derived sequences in vertebrate development. Mob DNA 2021; 12:1. [PMID: 33407840 PMCID: PMC7786948 DOI: 10.1186/s13100-020-00229-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 12/15/2020] [Indexed: 12/14/2022] Open
Abstract
Transposable elements (TEs) are major components of all vertebrate genomes that can cause deleterious insertions and genomic instability. However, depending on the specific genomic context of their insertion site, TE sequences can sometimes get positively selected, leading to what are called "exaptation" events. TE sequence exaptation constitutes an important source of novelties for gene, genome and organism evolution, giving rise to new regulatory sequences, protein-coding exons/genes and non-coding RNAs, which can play various roles beneficial to the host. In this review, we focus on the development of vertebrates, which present many derived traits such as bones, adaptive immunity and a complex brain. We illustrate how TE-derived sequences have given rise to developmental innovations in vertebrates and how they thereby contributed to the evolutionary success of this lineage.
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Affiliation(s)
- Ema Etchegaray
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364, Lyon, France.
| | - Magali Naville
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364, Lyon, France
| | - Jean-Nicolas Volff
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364, Lyon, France
| | - Zofia Haftek-Terreau
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364, Lyon, France
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15
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Tran A, Johnson DA. Mutational analysis identifies functional Rap1, Su(Hw), and CTCF insulator sites in Arabidopsis thaliana. PLANT CELL REPORTS 2020; 39:1743-1753. [PMID: 32959125 DOI: 10.1007/s00299-020-02601-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
Genetic analysis identifies multiple, potential protein binding sites important for insulator function in Arabidopsis thaliana: Rap1 site in UASrpg, Su(Hw) site in UASrpg, and CTCF site in BEAD1c. Three non-plant insulators UASrpg, BEAD1c, and gypsy isolated from Ashbya gossypii, Homo sapiens and Drosophila melanogaster gypsy retrotransposon, respectively, demonstrate insulator function in transgenic Arabidopsis thaliana. Here, the hypothesis that DNA sequences functional in A. thaliana are the same as those in the original host as previously assumed, was tested. Genetic analyses of the cloned fragments in an enhancer blocking assay system was performed through deletions and mutations to identify more precisely which sequences within the cloned fragments function as insulators. Significant loss of insulator activity was observed when the UASrpg Rap1 binding site R2 was mutated but not R1. Cloned fragments containing BEAD1c are effective insulators in our assay system and the previously investigated gypsy insulator is non-functional. Further analyses identified potential Su(Hw) and CTCF sites within UASrpg, of which only the Su(Hw) site was functional. Thus, the activity of non-plant insulators in A. thaliana is context dependent. These results support the hypothesis that insulator function is conserved across kingdoms.
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Affiliation(s)
- Anh Tran
- Biology Department, University of Ottawa, Ottawa, Ontario, Canada.
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16
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Azazi D, Mudge JM, Odom DT, Flicek P. Functional signatures of evolutionarily young CTCF binding sites. BMC Biol 2020; 18:132. [PMID: 32988407 PMCID: PMC7520972 DOI: 10.1186/s12915-020-00863-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 09/03/2020] [Indexed: 01/01/2023] Open
Abstract
Background The introduction of novel CTCF binding sites in gene regulatory regions in the rodent lineage is partly the effect of transposable element expansion, particularly in the murine lineage. The exact mechanism and functional impact of evolutionarily novel CTCF binding sites are not yet fully understood. We investigated the impact of novel subspecies-specific CTCF binding sites in two Mus genus subspecies, Mus musculus domesticus and Mus musculus castaneus, that diverged 0.5 million years ago. Results CTCF binding site evolution is influenced by the action of the B2-B4 family of transposable elements independently in both lineages, leading to the proliferation of novel CTCF binding sites. A subset of evolutionarily young sites may harbour transcriptional functionality as evidenced by the stability of their binding across multiple tissues in M. musculus domesticus (BL6), while overall the distance of subspecies-specific CTCF binding to the nearest transcription start sites and/or topologically associated domains (TADs) is largely similar to musculus-common CTCF sites. Remarkably, we discovered a recurrent regulatory architecture consisting of a CTCF binding site and an interferon gene that appears to have been tandemly duplicated to create a 15-gene cluster on chromosome 4, thus forming a novel BL6 specific immune locus in which CTCF may play a regulatory role. Conclusions Our results demonstrate that thousands of CTCF binding sites show multiple functional signatures rapidly after incorporation into the genome.
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Affiliation(s)
- Dhoyazan Azazi
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Jonathan M Mudge
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Duncan T Odom
- University of Cambridge, Cancer Research UK Cambridge Institute, Robinson Way, Cambridge, CB2 0RE, UK.,German Cancer Research Center (DKFZ), Division Regulatory Genomics and Cancer Evolution, 69120, Heidelberg, Germany
| | - Paul Flicek
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK. .,University of Cambridge, Cancer Research UK Cambridge Institute, Robinson Way, Cambridge, CB2 0RE, UK. .,Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.
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17
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Seruggia D, Fernández A, Cantero M, Fernández-Miñán A, Gomez-Skarmeta JL, Pelczar P, Montoliu L. Boundary sequences flanking the mouse tyrosinase locus ensure faithful pattern of gene expression. Sci Rep 2020; 10:15494. [PMID: 32968154 PMCID: PMC7511308 DOI: 10.1038/s41598-020-72543-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/02/2020] [Indexed: 12/28/2022] Open
Abstract
Control of gene expression is dictated by cell-type specific regulatory sequences that physically organize the structure of chromatin, including promoters, enhancers and insulators. While promoters and enhancers convey cell-type specific activating signals, insulators prevent the cross-talk of regulatory elements within adjacent loci and safeguard the specificity of action of promoters and enhancers towards their targets in a tissue specific manner. Using the mouse tyrosinase (Tyr) locus as an experimental model, a gene whose mutations are associated with albinism, we described the chromatin structure in cells at two distinct transcriptional states. Guided by chromatin structure, through the use of Chromosome Conformation Capture (3C), we identified sequences at the 5′ and 3′ boundaries of this mammalian gene that function as enhancers and insulators. By CRISPR/Cas9-mediated chromosomal deletion, we dissected the functions of these two regulatory elements in vivo in the mouse, at the endogenous chromosomal context, and proved their mechanistic role as genomic insulators, shielding the Tyr locus from the expression patterns of adjacent genes.
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Affiliation(s)
- Davide Seruggia
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Campus de Cantoblanco, Darwin 3, 28049, Madrid, Spain.,CIBERER-ISCIII, Madrid, Spain.,Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Almudena Fernández
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Campus de Cantoblanco, Darwin 3, 28049, Madrid, Spain.,CIBERER-ISCIII, Madrid, Spain
| | - Marta Cantero
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Campus de Cantoblanco, Darwin 3, 28049, Madrid, Spain.,CIBERER-ISCIII, Madrid, Spain
| | - Ana Fernández-Miñán
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-Universidad Pablo de Olavide-Junta de Andalucía, Seville, Spain
| | - José Luis Gomez-Skarmeta
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-Universidad Pablo de Olavide-Junta de Andalucía, Seville, Spain
| | - Pawel Pelczar
- Center for Transgenic Models, University of Basel, Basel, Switzerland
| | - Lluis Montoliu
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Campus de Cantoblanco, Darwin 3, 28049, Madrid, Spain. .,CIBERER-ISCIII, Madrid, Spain.
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18
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Khan M, Yan L, Lv B, Ji N, Shah S, Liu X, Song Z, Zhao Y, Wang X, Lv Z. The preparation of endotoxin-free genetically engineered murine B1 antisense RNA. Anal Biochem 2020; 599:113737. [PMID: 32305428 DOI: 10.1016/j.ab.2020.113737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 04/08/2020] [Accepted: 04/10/2020] [Indexed: 12/09/2022]
Abstract
One of the major limitations in the production of genetically engineered RNA from Escherichia coli (E. coli) is contamination by endotoxin. Here we report the first method that is capable of removing endotoxin from genetically engineered RNA. As a proof of concept, we transformed E. coli with a plasmid containing a tandem short interspersed nuclear elements from the mouse genome (SINE B1 elements). We then evaluated several extraction methods (SDS-NaCl centrifugation, SDS-NaCl filtration, TRIzol and SDS hot-phenol) and refinements thereof, and measured the resulting RNA yield, RNA purity, RNA integrity and endotoxin content. SDS-NaCl filtration with 2 mol/L NaCl, incorporating DEPC as an RNA protective agent, effectively removed endotoxin and resulted in a good RNA yield. Triton X-114 phase separation further reduced the endotoxin content of SDS-NaCl filtration-extracted RNA. RNA extracted by SDS-NaCl filtration with Triton X-114 phase separation did not cause adverse reactions in BALB/c mice and did not induce fever in rabbits when injected into these animals. The RNA met the requirements of nucleic acid reagents for in vivo experiments on animals.
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Affiliation(s)
- Murad Khan
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, China
| | - Lifang Yan
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, China
| | - Baixue Lv
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, Hubei Province, China; Hubei Province Key Laboratory of Molecular Imaging, Wuhan, 430022, Hubei Province, China
| | - Ning Ji
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, China
| | - Suleman Shah
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, China
| | - Xin Liu
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, China
| | - Zhixue Song
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, China
| | - Yufang Zhao
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, China
| | - Xiufang Wang
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, China.
| | - Zhanjun Lv
- Department of Genetics, Hebei Medical University, Hebei Key Lab of Laboratory Animal, Shijiazhuang, 050017, Hebei Province, China.
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19
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González-Rico FJ, Vicente-García C, Fernández A, Muñoz-Santos D, Montoliu L, Morales-Hernández A, Merino JM, Román AC, Fernández-Salguero PM. Alu retrotransposons modulate Nanog expression through dynamic changes in regional chromatin conformation via aryl hydrocarbon receptor. Epigenetics Chromatin 2020; 13:15. [PMID: 32169107 PMCID: PMC7071633 DOI: 10.1186/s13072-020-00336-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 03/02/2020] [Indexed: 12/19/2022] Open
Abstract
Transcriptional repression of Nanog is an important hallmark of stem cell differentiation. Chromatin modifications have been linked to the epigenetic profile of the Nanog gene, but whether chromatin organization actually plays a causal role in Nanog regulation is still unclear. Here, we report that the formation of a chromatin loop in the Nanog locus is concomitant to its transcriptional downregulation during human NTERA-2 cell differentiation. We found that two Alu elements flanking the Nanog gene were bound by the aryl hydrocarbon receptor (AhR) and the insulator protein CTCF during cell differentiation. Such binding altered the profile of repressive histone modifications near Nanog likely leading to gene insulation through the formation of a chromatin loop between the two Alu elements. Using a dCAS9-guided proteomic screening, we found that interaction of the histone methyltransferase PRMT1 and the chromatin assembly factor CHAF1B with the Alu elements flanking Nanog was required for chromatin loop formation and Nanog repression. Therefore, our results uncover a chromatin-driven, retrotransposon-regulated mechanism for the control of Nanog expression during cell differentiation.
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Affiliation(s)
- Francisco J González-Rico
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Av. de Elvas s/n, 06071, Badajoz, Spain
| | - Cristina Vicente-García
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, C/Darwin 3, 28049, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Almudena Fernández
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, C/Darwin 3, 28049, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Diego Muñoz-Santos
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, C/Darwin 3, 28049, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Lluís Montoliu
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, C/Darwin 3, 28049, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Antonio Morales-Hernández
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Av. de Elvas s/n, 06071, Badajoz, Spain
| | - Jaime M Merino
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Av. de Elvas s/n, 06071, Badajoz, Spain
| | - Angel-Carlos Román
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Av. de Elvas s/n, 06071, Badajoz, Spain.
| | - Pedro M Fernández-Salguero
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Av. de Elvas s/n, 06071, Badajoz, Spain.
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20
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The aryl hydrocarbon receptor: an environmental sensor integrating immune responses in health and disease. Nat Rev Immunol 2019; 19:184-197. [PMID: 30718831 DOI: 10.1038/s41577-019-0125-8] [Citation(s) in RCA: 638] [Impact Index Per Article: 127.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The environment, diet, microbiota and body's metabolism shape complex biological processes in health and disease. However, our understanding of the molecular pathways involved in these processes is still limited. The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that integrates environmental, dietary, microbial and metabolic cues to control complex transcriptional programmes in a ligand-specific, cell-type-specific and context-specific manner. In this Review, we summarize our current knowledge of AHR and the transcriptional programmes it controls in the immune system. Finally, we discuss the role of AHR in autoimmune and neoplastic diseases of the central nervous system, with a special focus on the gut immune system, the gut-brain axis and the therapeutic potential of targeting AHR in neurological disorders.
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21
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Petrie JL, Swan C, Ingram RM, Frame FM, Collins AT, Dumay-Odelot H, Teichmann M, Maitland NJ, White RJ. Effects on prostate cancer cells of targeting RNA polymerase III. Nucleic Acids Res 2019; 47:3937-3956. [PMID: 30820548 PMCID: PMC6486637 DOI: 10.1093/nar/gkz128] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 02/13/2019] [Accepted: 02/19/2019] [Indexed: 12/12/2022] Open
Abstract
RNA polymerase (pol) III occurs in two forms, containing either the POLR3G subunit or the related paralogue POLR3GL. Whereas POLR3GL is ubiquitous, POLR3G is enriched in undifferentiated cells. Depletion of POLR3G selectively triggers proliferative arrest and differentiation of prostate cancer cells, responses not elicited when POLR3GL is depleted. A small molecule pol III inhibitor can cause POLR3G depletion, induce similar differentiation and suppress proliferation and viability of cancer cells. This response involves control of the fate-determining factor NANOG by small RNAs derived from Alu short interspersed nuclear elements. Tumour initiating activity in vivo can be reduced by transient exposure to the pol III inhibitor. Untransformed prostate cells appear less sensitive than cancer cells to pol III depletion or inhibition, raising the possibility of a therapeutic window.
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Affiliation(s)
- John L Petrie
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Caroline Swan
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Richard M Ingram
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Fiona M Frame
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Anne T Collins
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Hélène Dumay-Odelot
- Université de Bordeaux, ARNA Laboratory, F-33076 Bordeaux, France INSERM, U1212 - CNRS UMR 5320, ARNA Laboratory, F-33000 Bordeaux, France
| | - Martin Teichmann
- Université de Bordeaux, ARNA Laboratory, F-33076 Bordeaux, France INSERM, U1212 - CNRS UMR 5320, ARNA Laboratory, F-33000 Bordeaux, France
| | - Norman J Maitland
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Robert J White
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
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22
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Román AC, Vicente-Page J, Pérez-Escudero A, Carvajal-González JM, Fernández-Salguero PM, de Polavieja GG. Histone H4 acetylation regulates behavioral inter-individual variability in zebrafish. Genome Biol 2018; 19:55. [PMID: 29695303 PMCID: PMC5922312 DOI: 10.1186/s13059-018-1428-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 03/29/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Animals can show very different behaviors even in isogenic populations, but the underlying mechanisms to generate this variability remain elusive. We use the zebrafish (Danio rerio) as a model to test the influence of histone modifications on behavior. RESULTS We find that laboratory and isogenic zebrafish larvae show consistent individual behaviors when swimming freely in identical wells or in reaction to stimuli. This behavioral inter-individual variability is reduced when we impair the histone deacetylation pathway. Individuals with high levels of histone H4 acetylation, and specifically H4K12, behave similarly to the average of the population, but those with low levels deviate from it. More precisely, we find a set of genomic regions whose histone H4 acetylation is reduced with the distance between the individual and the average population behavior. We find evidence that this modulation depends on a complex of Yin-yang 1 (YY1) and histone deacetylase 1 (HDAC1) that binds to and deacetylates these regions. These changes are not only maintained at the transcriptional level but also amplified, as most target regions are located near genes encoding transcription factors. CONCLUSIONS We suggest that stochasticity in the histone deacetylation pathway participates in the generation of genetic-independent behavioral inter-individual variability.
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Affiliation(s)
- Angel-Carlos Román
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Avenida Brasília s/n, 1400-038, Lisbon, Portugal. .,Instituto Cajal, Consejo Superior de Investigaciones Científicas, Av. Doctor Arce, 37, 28002, Madrid, Spain.
| | - Julián Vicente-Page
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Avenida Brasília s/n, 1400-038, Lisbon, Portugal.,Instituto Cajal, Consejo Superior de Investigaciones Científicas, Av. Doctor Arce, 37, 28002, Madrid, Spain
| | - Alfonso Pérez-Escudero
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Av. Doctor Arce, 37, 28002, Madrid, Spain.,Physics Department, MIT, Cambridge, Massachusetts, USA
| | - Jose M Carvajal-González
- Departamento de Bioquímica y Biología Molecular y Genética, Universidad de Extremadura, Av. de Elvas s/n, 06071, Badajoz, Spain
| | - Pedro M Fernández-Salguero
- Departamento de Bioquímica y Biología Molecular y Genética, Universidad de Extremadura, Av. de Elvas s/n, 06071, Badajoz, Spain
| | - Gonzalo G de Polavieja
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Avenida Brasília s/n, 1400-038, Lisbon, Portugal. .,Instituto Cajal, Consejo Superior de Investigaciones Científicas, Av. Doctor Arce, 37, 28002, Madrid, Spain.
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23
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Rico-Leo EM, Moreno-Marín N, González-Rico FJ, Barrasa E, Ortega-Ferrusola C, Martín-Muñoz P, Sánchez-Guardado LO, Llano E, Alvarez-Barrientos A, Infante-Campos A, Catalina-Fernández I, Hidalgo-Sánchez M, de Rooij DG, Pendás AM, Peña FJ, Merino JM, Fernández-Salguero PM. piRNA-associated proteins and retrotransposons are differentially expressed in murine testis and ovary of aryl hydrocarbon receptor deficient mice. Open Biol 2017; 6:rsob.160186. [PMID: 28003471 PMCID: PMC5204120 DOI: 10.1098/rsob.160186] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 11/14/2016] [Indexed: 11/22/2022] Open
Abstract
Previous studies suggested that the aryl hydrocarbon receptor (AhR) contributes to mice reproduction and fertility. However, the mechanisms involved remain mostly unknown. Retrotransposon silencing by Piwi-interacting RNAs (piRNAs) is essential for germ cell maturation and, remarkably, AhR has been identified as a regulator of murine B1-SINE retrotransposons. Here, using littermate AhR+/+ and AhR−/− mice, we report that AhR regulates the general course of spermatogenesis and oogenesis by a mechanism likely to be associated with piRNA-associated proteins, piRNAs and retrotransposons. piRNA-associated proteins MVH and Miwi are upregulated in leptotene to pachytene spermatocytes with a more precocious timing in AhR−/− than in AhR+/+ testes. piRNAs and transcripts from B1-SINE, LINE-1 and IAP retrotransposons increased at these meiotic stages in AhR-null testes. Moreover, B1-SINE transcripts colocalize with MVH and Miwi in leptonema and pachynema spermatocytes. Unexpectedly, AhR−/− males have increased sperm counts, higher sperm functionality and enhanced fertility than AhR+/+ mice. In contrast, piRNA-associated proteins and B1-SINE and IAP-derived transcripts are reduced in adult AhR−/− ovaries. Accordingly, AhR-null female mice have lower numbers of follicles when compared with AhR+/+ mice. Thus, AhR deficiency differentially affects testis and ovary development possibly by a process involving piRNA-associated proteins, piRNAs and transposable elements.
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Affiliation(s)
- Eva M Rico-Leo
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Nuria Moreno-Marín
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Francisco J González-Rico
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Eva Barrasa
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Cristina Ortega-Ferrusola
- Laboratorio de Reproducción y Espermatología Equina, Hospital Veterinario, Universidad de Extremadura, Cáceres, Spain
| | - Patricia Martín-Muñoz
- Laboratorio de Reproducción y Espermatología Equina, Hospital Veterinario, Universidad de Extremadura, Cáceres, Spain
| | - Luis O Sánchez-Guardado
- Departamento de Anatomía, Biología Celular y Zoología, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Elena Llano
- Departamento de Fisiología, Universidad de Salamanca, Salamanca, Spain.,Instituto de Biología Molecular y Celular del Cáncer (CSIC-Universidad de Salamanca), Salamanca, Spain
| | | | | | | | - Matías Hidalgo-Sánchez
- Departamento de Anatomía, Biología Celular y Zoología, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Dirk G de Rooij
- Reproductive Biology Group, Division of Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Alberto M Pendás
- Instituto de Biología Molecular y Celular del Cáncer (CSIC-Universidad de Salamanca), Salamanca, Spain
| | - Fernando J Peña
- Laboratorio de Reproducción y Espermatología Equina, Hospital Veterinario, Universidad de Extremadura, Cáceres, Spain
| | - Jaime M Merino
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Pedro M Fernández-Salguero
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
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24
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Karijolich J, Zhao Y, Alla R, Glaunsinger B. Genome-wide mapping of infection-induced SINE RNAs reveals a role in selective mRNA export. Nucleic Acids Res 2017; 45:6194-6208. [PMID: 28334904 PMCID: PMC5449642 DOI: 10.1093/nar/gkx180] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 03/08/2017] [Indexed: 12/11/2022] Open
Abstract
Short interspersed nuclear elements (SINEs) are retrotransposons evolutionarily derived from endogenous RNA Polymerase III RNAs. Though SINE elements have undergone exaptation into gene regulatory elements, how transcribed SINE RNA impacts transcriptional and post-transcriptional regulation is largely unknown. This is partly due to a lack of information regarding which of the loci have transcriptional potential. Here, we present an approach (short interspersed nuclear element sequencing, SINE-seq), which selectively profiles RNA Polymerase III-derived SINE RNA, thereby identifying transcriptionally active SINE loci. Applying SINE-seq to monitor murine B2 SINE expression during a gammaherpesvirus infection revealed transcription from 28 270 SINE loci, with ∼50% of active SINE elements residing within annotated RNA Polymerase II loci. Furthermore, B2 RNA can form intermolecular RNA–RNA interactions with complementary mRNAs, leading to nuclear retention of the targeted mRNA via a mechanism involving p54nrb. These findings illuminate a pathway for the selective regulation of mRNA export during stress via retrotransposon activation.
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Affiliation(s)
- John Karijolich
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720-3370, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3370, USA.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232-2363, USA
| | - Yang Zhao
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232-2363, USA
| | - Ravi Alla
- California Institute for Quantitative Biology, University of California, Berkeley, CA 94720-3370, USA
| | - Britt Glaunsinger
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720-3370, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3370, USA.,California Institute for Quantitative Biology, University of California, Berkeley, CA 94720-3370, USA
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25
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Systematic identification and characterization of regulatory elements derived from human endogenous retroviruses. PLoS Genet 2017; 13:e1006883. [PMID: 28700586 PMCID: PMC5529029 DOI: 10.1371/journal.pgen.1006883] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 07/26/2017] [Accepted: 06/21/2017] [Indexed: 12/26/2022] Open
Abstract
Human endogenous retroviruses (HERVs) and other long terminal repeat (LTR)-type retrotransposons (HERV/LTRs) have regulatory elements that possibly influence the transcription of host genes. We systematically identified and characterized these regulatory elements based on publicly available datasets of ChIP-Seq of 97 transcription factors (TFs) provided by ENCODE and Roadmap Epigenomics projects. We determined transcription factor-binding sites (TFBSs) using the ChIP-Seq datasets and identified TFBSs observed on HERV/LTR sequences (HERV-TFBSs). Overall, 794,972 HERV-TFBSs were identified. Subsequently, we identified "HERV/LTR-shared regulatory element (HSRE)," defined as a TF-binding motif in HERV-TFBSs, shared within a substantial fraction of a HERV/LTR type. HSREs could be an indication that the regulatory elements of HERV/LTRs are present before their insertions. We identified 2,201 HSREs, comprising specific associations of 354 HERV/LTRs and 84 TFs. Clustering analysis showed that HERV/LTRs can be grouped according to the TF binding patterns; HERV/LTR groups bounded to pluripotent TFs (e.g., SOX2, POU5F1, and NANOG), embryonic endoderm/mesendoderm TFs (e.g., GATA4/6, SOX17, and FOXA1/2), hematopoietic TFs (e.g., SPI1 (PU1), GATA1/2, and TAL1), and CTCF were identified. Regulatory elements of HERV/LTRs tended to locate nearby and/or interact three-dimensionally with the genes involved in immune responses, indicating that the regulatory elements play an important role in controlling the immune regulatory network. Further, we demonstrated subgroup-specific TF binding within LTR7, LTR5B, and LTR5_Hs, indicating that gains or losses of the regulatory elements occurred during genomic invasions of the HERV/LTRs. Finally, we constructed dbHERV-REs, an interactive database of HERV/LTR regulatory elements (http://herv-tfbs.com/). This study provides fundamental information in understanding the impact of HERV/LTRs on host transcription, and offers insights into the transcriptional modulation systems of HERV/LTRs and ancestral HERVs.
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26
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27
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Hong R, Lin B, Lu X, Lai LT, Chen X, Sanyal A, Ng HH, Zhang K, Zhang LF. High-resolution RNA allelotyping along the inactive X chromosome: evidence of RNA polymerase III in regulating chromatin configuration. Sci Rep 2017; 7:45460. [PMID: 28368037 PMCID: PMC5377358 DOI: 10.1038/srep45460] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 03/02/2017] [Indexed: 01/02/2023] Open
Abstract
We carried out padlock capture, a high-resolution RNA allelotyping method, to study X chromosome inactivation (XCI). We examined the gene reactivation pattern along the inactive X (Xi), after Xist (X-inactive specific transcript), a prototype long non-coding RNA essential for establishing X chromosome inactivation (XCI) in early embryos, is conditionally deleted from Xi in somatic cells (Xi∆Xist). We also monitored the behaviors of X-linked non-coding transcripts before and after XCI. In each mutant cell line, gene reactivation occurs to ~6% genes along Xi∆Xist in a recognizable pattern. Genes with upstream regions enriched for SINEs are prone to be reactivated. SINE is a class of retrotransposon transcribed by RNA polymerase III (Pol III). Intriguingly, a significant fraction of Pol III transcription from non-coding regions is not subjected to Xist-mediated transcriptional silencing. Pol III inhibition affects gene reactivation status along Xi∆Xist, alters chromatin configuration and interferes with the establishment XCI during in vitro differentiation of ES cells. These results suggest that Pol III transcription is involved in chromatin structure re-organization during the onset of XCI and functions as a general mechanism regulating chromatin configuration in mammalian cells.
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Affiliation(s)
- Ru Hong
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore
| | - Bingqing Lin
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore
| | - Xinyi Lu
- Genome Institute of Singapore, 138672, Singapore
| | - Lan-Tian Lai
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore
| | - Xin Chen
- Division of Mathematical Sciences, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
| | - Amartya Sanyal
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore
| | - Huck-Hui Ng
- Genome Institute of Singapore, 138672, Singapore
| | - Kun Zhang
- Department of Bioengineering, University of California at San Diego, La Jolla, CA 92093, USA
| | - Li-Feng Zhang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore
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28
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Pauli T, Vedder L, Dowling D, Petersen M, Meusemann K, Donath A, Peters RS, Podsiadlowski L, Mayer C, Liu S, Zhou X, Heger P, Wiehe T, Hering L, Mayer G, Misof B, Niehuis O. Transcriptomic data from panarthropods shed new light on the evolution of insulator binding proteins in insects : Insect insulator proteins. BMC Genomics 2016; 17:861. [PMID: 27809783 PMCID: PMC5094011 DOI: 10.1186/s12864-016-3205-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 10/25/2016] [Indexed: 01/19/2023] Open
Abstract
Background Body plan development in multi-cellular organisms is largely determined by homeotic genes. Expression of homeotic genes, in turn, is partially regulated by insulator binding proteins (IBPs). While only a few enhancer blocking IBPs have been identified in vertebrates, the common fruit fly Drosophila melanogaster harbors at least twelve different enhancer blocking IBPs. We screened recently compiled insect transcriptomes from the 1KITE project and genomic and transcriptomic data from public databases, aiming to trace the origin of IBPs in insects and other arthropods. Results Our study shows that the last common ancestor of insects (Hexapoda) already possessed a substantial number of IBPs. Specifically, of the known twelve insect IBPs, at least three (i.e., CP190, Su(Hw), and CTCF) already existed prior to the evolution of insects. Furthermore we found GAF orthologs in early branching insect orders, including Zygentoma (silverfish and firebrats) and Diplura (two-pronged bristletails). Mod(mdg4) is most likely a derived feature of Neoptera, while Pita is likely an evolutionary novelty of holometabolous insects. Zw5 appears to be restricted to schizophoran flies, whereas BEAF-32, ZIPIC and the Elba complex, are probably unique to the genus Drosophila. Selection models indicate that insect IBPs evolved under neutral or purifying selection. Conclusions Our results suggest that a substantial number of IBPs either pre-date the evolution of insects or evolved early during insect evolution. This suggests an evolutionary history of insulator binding proteins in insects different to that previously thought. Moreover, our study demonstrates the versatility of the 1KITE transcriptomic data for comparative analyses in insects and other arthropods. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3205-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Thomas Pauli
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany.
| | - Lucia Vedder
- University of Tübingen, Geschwister-Scholl-Platz, 72074, Tübingen, Germany
| | - Daniel Dowling
- Johannes Gutenberg University Mainz, Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Malte Petersen
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany
| | - Karen Meusemann
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany.,Department for Evolutionary Biology and Ecology (Institut for Biology I, Zoology), University of Freiburg, Hauptstr. 1, 79104, Freiburg, Germany.,Australian National Insect Collection, CSIRO National Research Collections Australia, Clunies Ross Street, Acton, ACT, 2601, Australia
| | - Alexander Donath
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany
| | - Ralph S Peters
- Zoological Research Museum Alexander Koenig, Arthropod Department, Adenauerallee 160, 53113, Bonn, Germany
| | - Lars Podsiadlowski
- University of Bonn, Institute of Evolutionary Biology and Ecology, An der Immenburg 1, 53121, Bonn, Germany
| | - Christoph Mayer
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany
| | - Shanlin Liu
- China National GeneBank-Shenzhen, BGI-Shenzhen, Shenzhen, Guangdong Province, 518083, China.,Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350, Copenhagen, Denmark
| | - Xin Zhou
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, 100193, China.,College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Peter Heger
- University of Cologne, Cologne Biocenter, Institute for Genetics, Zülpicher Straße 47a, 50674, Köln, Germany
| | - Thomas Wiehe
- University of Cologne, Cologne Biocenter, Institute for Genetics, Zülpicher Straße 47a, 50674, Köln, Germany
| | - Lars Hering
- Department of Zoology, University of Kassel, Heinrich-Plett-Str. 40, 34132, Kassel, Germany
| | - Georg Mayer
- Department of Zoology, University of Kassel, Heinrich-Plett-Str. 40, 34132, Kassel, Germany
| | - Bernhard Misof
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany
| | - Oliver Niehuis
- Center of Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Adenauerallee 160, 51113, Bonn, Germany.
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29
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Warren IA, Naville M, Chalopin D, Levin P, Berger CS, Galiana D, Volff JN. Evolutionary impact of transposable elements on genomic diversity and lineage-specific innovation in vertebrates. Chromosome Res 2016; 23:505-31. [PMID: 26395902 DOI: 10.1007/s10577-015-9493-5] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Since their discovery, a growing body of evidence has emerged demonstrating that transposable elements are important drivers of species diversity. These mobile elements exhibit a great variety in structure, size and mechanisms of transposition, making them important putative actors in organism evolution. The vertebrates represent a highly diverse and successful lineage that has adapted to a wide range of different environments. These animals also possess a rich repertoire of transposable elements, with highly diverse content between lineages and even between species. Here, we review how transposable elements are driving genomic diversity and lineage-specific innovation within vertebrates. We discuss the large differences in TE content between different vertebrate groups and then go on to look at how they affect organisms at a variety of levels: from the structure of chromosomes to their involvement in the regulation of gene expression, as well as in the formation and evolution of non-coding RNAs and protein-coding genes. In the process of doing this, we highlight how transposable elements have been involved in the evolution of some of the key innovations observed within the vertebrate lineage, driving the group's diversity and success.
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Affiliation(s)
- Ian A Warren
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Magali Naville
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Domitille Chalopin
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France.,Department of Genetics, University of Georgia, Athens, Georgia, 30602, USA
| | - Perrine Levin
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Chloé Suzanne Berger
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Delphine Galiana
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Jean-Nicolas Volff
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR5242, Ecole Normale Supérieure de Lyon, Lyon, France.
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30
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Abstract
Retrotransposons have generated about 40 % of the human genome. This review examines the strategies the cell has evolved to coexist with these genomic "parasites", focussing on the non-long terminal repeat retrotransposons of humans and mice. Some of the restriction factors for retrotransposition, including the APOBECs, MOV10, RNASEL, SAMHD1, TREX1, and ZAP, also limit replication of retroviruses, including HIV, and are part of the intrinsic immune system of the cell. Many of these proteins act in the cytoplasm to degrade retroelement RNA or inhibit its translation. Some factors act in the nucleus and involve DNA repair enzymes or epigenetic processes of DNA methylation and histone modification. RISC and piRNA pathway proteins protect the germline. Retrotransposon control is relaxed in some cell types, such as neurons in the brain, stem cells, and in certain types of disease and cancer, with implications for human health and disease. This review also considers potential pitfalls in interpreting retrotransposon-related data, as well as issues to consider for future research.
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Affiliation(s)
- John L. Goodier
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA 212051
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31
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Mulero-Navarro S, Fernandez-Salguero PM. New Trends in Aryl Hydrocarbon Receptor Biology. Front Cell Dev Biol 2016; 4:45. [PMID: 27243009 PMCID: PMC4863130 DOI: 10.3389/fcell.2016.00045] [Citation(s) in RCA: 180] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 04/28/2016] [Indexed: 12/28/2022] Open
Abstract
Traditionally considered as a critical intermediate in the toxic and carcinogenic response to dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD), the Aryl hydrocarbon/Dioxin receptor (AhR) has proven to be also an important regulator of cell physiology and organ homeostasis. AhR has become an interesting and actual area of research mainly boosted by a significant number of recent studies analyzing its contribution to the proper functioning of the immune, hepatic, cardiovascular, vascular and reproductive systems. At the cellular level, AhR establishes functional interactions with signaling pathways governing cell proliferation and cell cycle, cell morphology, cell adhesion and cell migration. Two exciting new aspects in AhR biology deal with its implication in the control of cell differentiation and its more than likely involvement in cell pluripotency and stemness. In fact, it is possible that AhR could help modulate the balance between differentiation and pluripotency in normal and transformed tumor cells. At the molecular level, AhR regulates an increasingly large array of physiologically relevant genes either by traditional transcription-dependent mechanisms or by unforeseen processes involving genomic insulators, chromatin dynamics and the transcription of mobile genetic elements. AhR is also closely related to epigenetics, not only from the point of view of target gene expression but also with respect to its own regulation by promoter methylation. It is reasonable to consider that deregulation of these many functions could have a causative role, or at least contribute to, human disease. Consequently, several laboratories have proposed that AhR could be a valuable tool as diagnostic marker and/or therapeutic target in human pathologies. An additional point of interest is the possibility of regulating AhR activity by endogenous non-toxic low weight molecules agonist or antagonist molecules that could be present or included in the diet. In this review, we will address these molecular and functional features of AhR biology within physiological and pathological contexts.
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Affiliation(s)
- Sonia Mulero-Navarro
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura Badajoz, Spain
| | - Pedro M Fernandez-Salguero
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura Badajoz, Spain
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32
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Gao Z, Bu Y, Liu X, Wang X, Zhang G, Wang E, Ding S, Liu Y, Shi R, Li Q, Fu J, Yu Z. TCDD promoted EMT of hFPECs via AhR, which involved the activation of EGFR/ERK signaling. Toxicol Appl Pharmacol 2016; 298:48-55. [PMID: 26971374 DOI: 10.1016/j.taap.2016.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 02/15/2016] [Accepted: 03/08/2016] [Indexed: 02/01/2023]
Abstract
One critical step of second palatal fusion is the newly formed medial epithelia seam (MES) disintegration, which involves apoptosis, epithelial to mesenchymal transition (EMT), and cell migration. Although the environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces cleft palate at high rates, little is known about the effects of TCDD exposure on the fate of palatal epithelial cells. By using primary epithelial cells isolated from human fetal palatal shelves (hFPECs), we show that TCDD increased cell proliferation and EMT, as demonstrated by increased the epithelial markers (E-cadherin and cytokeratin14) and enhanced the mesenchymal markers (vimentin and fibronectin), but had no effect on cell migration and apoptosis. TCDD exposure led to a dose-dependent increase in Slug protein expression. Coimmunoprecipitation revealed that TCDD promoted AhR to form a protein complex with Slug. ChIP assay confirmed that TCDD exposure recruited AhR to the xenobiotic responsive element of Slug promoter. Knockdown of AhR by siRNA remarkably weakened TCDD-induced binding of AhR to the XRE promoter of slug, thereby suppressed TCDD-induced vimentin. Further experiment showed that TCDD stimulated EGFR phosphorylation did not influence the TGFβ3/Smad signaling; whereas TCDD increased phosphorylation of ERK1/2 and p38 with no effect on activation of JNK. By using varieties of inhibitors, we confirmed that TCDD promoted proliferation and EMT of hFPECs via activation of EGFR/ERK pathway. These data make a novel contribution to the molecular mechanism of cleft palate by TCDD.
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Affiliation(s)
- Zhan Gao
- School of Public Health, Xinxiang Medical University, 453003, China; The Fifth Affiliated Hospital, Zhengzhou University, 450052, China
| | - Yongjun Bu
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Xiaozhuan Liu
- Medical College, Henan University of Science & Technology, 471023, China
| | - Xugang Wang
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Guofu Zhang
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Erhui Wang
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Shibin Ding
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Yongfeng Liu
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Ruling Shi
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Qiaoyun Li
- The Fifth Affiliated Hospital, Zhengzhou University, 450052, China
| | - Jianhong Fu
- The Fifth Affiliated Hospital, Zhengzhou University, 450052, China
| | - Zengli Yu
- School of Public Health, Xinxiang Medical University, 453003, China; School of Public Health, Zhengzhou University, 450001, China.
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33
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Morales-Hernández A, González-Rico FJ, Román AC, Rico-Leo E, Alvarez-Barrientos A, Sánchez L, Macia Á, Heras SR, García-Pérez JL, Merino JM, Fernández-Salguero PM. Alu retrotransposons promote differentiation of human carcinoma cells through the aryl hydrocarbon receptor. Nucleic Acids Res 2016; 44:4665-83. [PMID: 26883630 PMCID: PMC4889919 DOI: 10.1093/nar/gkw095] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 02/09/2016] [Indexed: 12/18/2022] Open
Abstract
Cell differentiation is a central process in development and in cancer growth and dissemination. OCT4 (POU5F1) and NANOG are essential for cell stemness and pluripotency; yet, the mechanisms that regulate their expression remain largely unknown. Repetitive elements account for almost half of the Human Genome; still, their role in gene regulation is poorly understood. Here, we show that the dioxin receptor (AHR) leads to differentiation of human carcinoma cells through the transcriptional upregulation of Alu retrotransposons, whose RNA transcripts can repress pluripotency genes. Despite the genome-wide presence of Alu elements, we provide evidences that those located at the NANOG and OCT4 promoters bind AHR, are transcribed by RNA polymerase-III and repress NANOG and OCT4 in differentiated cells. OCT4 and NANOG repression likely involves processing of Alu-derived transcripts through the miRNA machinery involving the Microprocessor and RISC. Consistently, stable AHR knockdown led to basal undifferentiation, impaired Alus transcription and blockade of OCT4 and NANOG repression. We suggest that transcripts produced from AHR-regulated Alu retrotransposons may control the expression of stemness genes OCT4 and NANOG during differentiation of carcinoma cells. The control of discrete Alu elements by specific transcription factors may have a dynamic role in genome regulation under physiological and diseased conditions.
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Affiliation(s)
- Antonio Morales-Hernández
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
| | - Francisco J González-Rico
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
| | - Angel C Román
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avenida Doctor Arce 37, 28002-Madrid, Spain
| | - Eva Rico-Leo
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
| | - Alberto Alvarez-Barrientos
- Servicio de Técnicas Aplicadas a las Biociencias, Universidad de Extremadura, Avenida de Elvas s/n 06071-Badajoz, Spain
| | - Laura Sánchez
- GENYO. Centro de Genómica e Investigación Oncológica: Pfizer/Universidad de Granada/Junta de Andalucía, Avda. de la Ilustración 114, PTS Granada, 18016-Granada, Spain
| | - Ángela Macia
- GENYO. Centro de Genómica e Investigación Oncológica: Pfizer/Universidad de Granada/Junta de Andalucía, Avda. de la Ilustración 114, PTS Granada, 18016-Granada, Spain
| | - Sara R Heras
- GENYO. Centro de Genómica e Investigación Oncológica: Pfizer/Universidad de Granada/Junta de Andalucía, Avda. de la Ilustración 114, PTS Granada, 18016-Granada, Spain
| | - José L García-Pérez
- GENYO. Centro de Genómica e Investigación Oncológica: Pfizer/Universidad de Granada/Junta de Andalucía, Avda. de la Ilustración 114, PTS Granada, 18016-Granada, Spain
| | - Jaime M Merino
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
| | - Pedro M Fernández-Salguero
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071-Badajoz, Spain
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Contador-Troca M, Alvarez-Barrientos A, Merino JM, Morales-Hernández A, Rodríguez MI, Rey-Barroso J, Barrasa E, Cerezo-Guisado MI, Catalina-Fernández I, Sáenz-Santamaría J, Oliver FJ, Fernandez-Salguero PM. Dioxin receptor regulates aldehyde dehydrogenase to block melanoma tumorigenesis and metastasis. Mol Cancer 2015; 14:148. [PMID: 26242870 PMCID: PMC4524442 DOI: 10.1186/s12943-015-0419-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 07/22/2015] [Indexed: 01/16/2023] Open
Abstract
Background The dioxin (AhR) receptor can have oncogenic or tumor suppressor activities depending on the phenotype of the target cell. We have shown that AhR knockdown promotes melanoma primary tumorigenesis and lung metastasis in the mouse and that human metastatic melanomas had reduced AhR levels with respect to benign nevi. Methods Mouse melanoma B16F10 cells were engineered by retroviral transduction to stably downregulate AhR expression, Aldh1a1 expression or both. They were characterized for Aldh1a1 activity, stem cell markers and migration and invasion in vitro. Their tumorigenicity in vivo was analyzed using xenografts and lung metastasis assays as well as in vivo imaging. Results Depletion of aldehyde dehydrogenase 1a1 (Aldh1a1) impairs the pro-tumorigenic and pro-metastatic advantage of melanoma cells lacking AhR expression (sh-AhR). Thus, Aldh1a1 knockdown in sh-AhR cells (sh-AhR + sh-Aldh1a1) diminished their migration and invasion potentials and blocked tumor growth and metastasis to the lungs in immunocompetent AhR+/+ recipient mice. However, Aldh1a1 downmodulation in AhR-expressing B16F10 cells did not significantly affect tumor growth in vivo. Aldh1a1 knockdown reduced the high levels of CD133+/CD29+/CD44+ cells, melanosphere size and the expression of the pluripotency marker Sox2 in sh-AhR cells. Interestingly, Sox2 increased Aldh1a1 expression in sh-AhR but not in sh-AhR + sh-Aldh1a1 cells, suggesting that Aldh1a1 and Sox2 may be co-regulated in melanoma cells. In vivo imaging revealed that mice inoculated with AhR + Aldh1a1 knockdown cells had reduced tumor burden and enhanced survival than those receiving Aldh1a1-expressing sh-AhR cells. Conclusions Aldh1a1 overactivation in an AhR-deficient background enhances melanoma progression. Since AhR may antagonize the protumoral effects of Aldh1a1, the AhRlow-Aldh1a1high phenotype could be indicative of bad outcome in melanoma. Electronic supplementary material The online version of this article (doi:10.1186/s12943-015-0419-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- María Contador-Troca
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, 06071, Badajoz, Spain.
| | | | - Jaime M Merino
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, 06071, Badajoz, Spain.
| | | | - María I Rodríguez
- Instituto de Parasitología y Biomedicina López Neyra, CSIC, 18016, Granada, Spain.
| | - Javier Rey-Barroso
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, 06071, Badajoz, Spain.
| | - Eva Barrasa
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, 06071, Badajoz, Spain.
| | - María I Cerezo-Guisado
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, 06071, Badajoz, Spain.
| | | | - Javier Sáenz-Santamaría
- Servicio de Anatomía Patológica, Hospital Universitario Infanta Cristina, 06071, Badajoz, Spain.
| | - Francisco J Oliver
- Instituto de Parasitología y Biomedicina López Neyra, CSIC, 18016, Granada, Spain.
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Abstract
Insulators are regulatory elements that help to organize eukaryotic chromatin via enhancer-blocking and chromatin barrier activity. Although there are several examples of transposable element (TE)-derived insulators, the contribution of TEs to human insulators has not been systematically explored. Mammalian-wide interspersed repeats (MIRs) are a conserved family of TEs that have substantial regulatory capacity and share sequence characteristics with tRNA-related insulators. We sought to evaluate whether MIRs can serve as insulators in the human genome. We applied a bioinformatic screen using genome sequence and functional genomic data from CD4(+) T cells to identify a set of 1,178 predicted MIR insulators genome-wide. These predicted MIR insulators were computationally tested to serve as chromatin barriers and regulators of gene expression in CD4(+) T cells. The activity of predicted MIR insulators was experimentally validated using in vitro and in vivo enhancer-blocking assays. MIR insulators are enriched around genes of the T-cell receptor pathway and reside at T-cell-specific boundaries of repressive and active chromatin. A total of 58% of the MIR insulators predicted here show evidence of T-cell-specific chromatin barrier and gene regulatory activity. MIR insulators appear to be CCCTC-binding factor (CTCF) independent and show a distinct local chromatin environment with marked peaks for RNA Pol III and a number of histone modifications, suggesting that MIR insulators recruit transcriptional complexes and chromatin modifying enzymes in situ to help establish chromatin and regulatory domains in the human genome. The provisioning of insulators by MIRs across the human genome suggests a specific mechanism by which TE sequences can be used to modulate gene regulatory networks.
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Seruggia D, Fernández A, Cantero M, Pelczar P, Montoliu L. Functional validation of mouse tyrosinase non-coding regulatory DNA elements by CRISPR-Cas9-mediated mutagenesis. Nucleic Acids Res 2015; 43:4855-67. [PMID: 25897126 PMCID: PMC4446435 DOI: 10.1093/nar/gkv375] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 04/08/2015] [Indexed: 12/26/2022] Open
Abstract
Newly developed genome-editing tools, such as the clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 system, allow simple and rapid genetic modification in most model organisms and human cell lines. Here, we report the production and analysis of mice carrying the inactivation via deletion of a genomic insulator, a key non-coding regulatory DNA element found 5' upstream of the mouse tyrosinase (Tyr) gene. Targeting sequences flanking this boundary in mouse fertilized eggs resulted in the efficient deletion or inversion of large intervening DNA fragments delineated by the RNA guides. The resulting genome-edited mice showed a dramatic decrease in Tyr gene expression as inferred from the evident decrease of coat pigmentation, thus supporting the functionality of this boundary sequence in vivo, at the endogenous locus. Several potential off-targets bearing sequence similarity with each of the two RNA guides used were analyzed and found to be largely intact. This study reports how non-coding DNA elements, even if located in repeat-rich genomic sequences, can be efficiently and functionally evaluated in vivo and, furthermore, it illustrates how the regulatory elements described by the ENCODE and EPIGENOME projects, in the mouse and human genomes, can be systematically validated.
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Affiliation(s)
- Davide Seruggia
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Campus Cantoblanco, Darwin 3, 28049 Madrid, Spain CIBERER-ISCIII, Madrid, Spain
| | - Almudena Fernández
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Campus Cantoblanco, Darwin 3, 28049 Madrid, Spain CIBERER-ISCIII, Madrid, Spain
| | - Marta Cantero
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Campus Cantoblanco, Darwin 3, 28049 Madrid, Spain CIBERER-ISCIII, Madrid, Spain
| | - Pawel Pelczar
- Institute of Laboratory Animal Science, University of Zurich, Zurich, Switzerland
| | - Lluis Montoliu
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Campus Cantoblanco, Darwin 3, 28049 Madrid, Spain CIBERER-ISCIII, Madrid, Spain
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Conti A, Carnevali D, Bollati V, Fustinoni S, Pellegrini M, Dieci G. Identification of RNA polymerase III-transcribed Alu loci by computational screening of RNA-Seq data. Nucleic Acids Res 2014; 43:817-35. [PMID: 25550429 PMCID: PMC4333407 DOI: 10.1093/nar/gku1361] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Of the ∼1.3 million Alu elements in the human genome, only a tiny number are estimated to be active in transcription by RNA polymerase (Pol) III. Tracing the individual loci from which Alu transcripts originate is complicated by their highly repetitive nature. By exploiting RNA-Seq data sets and unique Alu DNA sequences, we devised a bioinformatic pipeline allowing us to identify Pol III-dependent transcripts of individual Alu elements. When applied to ENCODE transcriptomes of seven human cell lines, this search strategy identified ∼1300 Alu loci corresponding to detectable transcripts, with ∼120 of them expressed in at least three cell lines. In vitro transcription of selected Alus did not reflect their in vivo expression properties, and required the native 5′-flanking region in addition to internal promoter. We also identified a cluster of expressed AluYa5-derived transcription units, juxtaposed to snaR genes on chromosome 19, formed by a promoter-containing left monomer fused to an Alu-unrelated downstream moiety. Autonomous Pol III transcription was also revealed for Alus nested within Pol II-transcribed genes. The ability to investigate Alu transcriptomes at single-locus resolution will facilitate both the identification of novel biologically relevant Alu RNAs and the assessment of Alu expression alteration under pathological conditions.
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Affiliation(s)
- Anastasia Conti
- Department of Life Sciences, University of Parma, 43124 Parma, Italy Department of Clinical and Experimental Medicine, University of Parma, 43126 Parma, Italy
| | - Davide Carnevali
- Department of Life Sciences, University of Parma, 43124 Parma, Italy
| | - Valentina Bollati
- Department of Clinical Sciences and Community Health, University of Milano and Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via S. Barnaba, 8-20122 Milano, Italy
| | - Silvia Fustinoni
- Department of Clinical Sciences and Community Health, University of Milano and Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via S. Barnaba, 8-20122 Milano, Italy
| | - Matteo Pellegrini
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA 90095-7239, USA
| | - Giorgio Dieci
- Department of Life Sciences, University of Parma, 43124 Parma, Italy
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Hallwass M, de Oliveira AS, de Campos Dianese E, Lohuis D, Boiteux LS, Inoue-Nagata AK, Resende RO, Kormelink R. The Tomato spotted wilt virus cell-to-cell movement protein (NSM ) triggers a hypersensitive response in Sw-5-containing resistant tomato lines and in Nicotiana benthamiana transformed with the functional Sw-5b resistance gene copy. MOLECULAR PLANT PATHOLOGY 2014; 15:871-80. [PMID: 24720811 PMCID: PMC6638845 DOI: 10.1111/mpp.12144] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Although the Sw-5 gene cluster has been cloned, and Sw-5b has been identified as the functional gene copy that confers resistance to Tomato spotted wilt virus (TSWV), its avirulence (Avr) determinant has not been identified to date. Nicotiana tabacum 'SR1' plants transformed with a copy of the Sw-5b gene are immune without producing a clear visual response on challenge with TSWV, whereas it is shown here that N. benthamiana transformed with Sw-5b gives a rapid and conspicuous hypersensitive response (HR). Using these plants, from all structural and non-structural TSWV proteins tested, the TSWV cell-to-cell movement protein (NSM ) was confirmed as the Avr determinant using a Potato virus X (PVX) replicon or a non-replicative pEAQ-HT expression vector system. HR was induced in Sw-5b-transgenic N. benthamiana as well as in resistant near-isogenic tomato lines after agroinfiltration with a functional cell-to-cell movement protein (NSM ) from a resistance-inducing (RI) TSWV strain (BR-01), but not with NSM from a Sw-5 resistance-breaking (RB) strain (GRAU). This is the first biological demonstration that Sw-5-mediated resistance is triggered by the TSWV NSM cell-to-cell movement protein.
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Affiliation(s)
- Mariana Hallwass
- Laboratory of Virology, Department of Plant Sciences, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands; Instituto de Ciências Biológicas, Departamento de Biologia Celular, Universidade de Brasília, ICC-Sul Asa Norte 70910-900, Brasília, DF, Brazil
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Wang J, Lawry ST, Cohen AL, Jia S. Chromosome boundary elements and regulation of heterochromatin spreading. Cell Mol Life Sci 2014; 71:4841-52. [PMID: 25192661 PMCID: PMC4234687 DOI: 10.1007/s00018-014-1725-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 08/27/2014] [Accepted: 08/29/2014] [Indexed: 11/29/2022]
Abstract
Chromatin is generally classified as euchromatin or heterochromatin, each with distinct histone modifications, compaction levels, and gene expression patterns. Although the proper formation of heterochromatin is essential for maintaining genome integrity and regulating gene expression, heterochromatin can also spread into neighboring regions in a sequence-independent manner, leading to the inactivation of genes. Because the distance of heterochromatin spreading is stochastic, the formation of boundaries, which block the spreading of heterochromatin, is critical for maintaining stable gene expression patterns. Here we review the current understanding of the mechanisms underlying heterochromatin spreading and boundary formation.
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Affiliation(s)
- Jiyong Wang
- Department of Biological Sciences, Columbia University, New York, NY, USA
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40
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Román AC, González-Rico FJ, Fernández-Salguero PM. B1-SINE retrotransposons: Establishing genomic insulatory networks. Mob Genet Elements 2014; 1:66-70. [PMID: 22016846 DOI: 10.4161/mge.1.1.15455] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2011] [Accepted: 03/14/2011] [Indexed: 11/19/2022] Open
Abstract
More than half the size of most mammalian genomes is composed by repetitive sequences. Short Interspersed Nuclear Element (SINE) retrotransposons constitute one of the main components of the genomic repetitive fraction. The abundance and evolutionary conservation of these sequences support their contribution to maintain the stability and proper function of the genome. Several recent studies have unveiled some of these intriguing tasks, which include, but are not limited to the control of transcriptional regulation and the organization of the chromatin. Here, we will comment on our recent report characterizing the insulator/boundary activity of a novel B1 SINE retrotransposon (B1-X35S) widely present in the mouse genome. A remarkable finding was that B1-X35S-dependent insulation required not only the combinatorial binding of transcription factors dioxin receptor (AhR) and Snai2/Slug, but also a molecular switch between RNA Polymerases (Pol) Pol III and Pol II. Moreover, B1-X35S seemingly forms heterochromatic barriers next to gene promoters that bioinformatic analyses revealed to dramatically change from embryonic stem (ES) to fibroblasts cells. The vast presence of B1-X35S in the mouse genome (over 14,000 instances) opens the exciting possibility of a complex network in which retrotransposon-derived insulators convert biological input signals into transcriptional responses by defining gene expression domains. The importance of such mechanism in different cellular and physiological processes will be discussed.
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Affiliation(s)
- Angel C Román
- Departamento de Bioquímica y Biología Molecular; Facultad de Ciencias; Universidad de Extremadura; Badajoz, Spain
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Schoborg T, Labrador M. Expanding the roles of chromatin insulators in nuclear architecture, chromatin organization and genome function. Cell Mol Life Sci 2014; 71:4089-113. [PMID: 25012699 PMCID: PMC11113341 DOI: 10.1007/s00018-014-1672-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 05/31/2014] [Accepted: 06/23/2014] [Indexed: 01/08/2023]
Abstract
Of the numerous classes of elements involved in modulating eukaryotic chromosome structure and function, chromatin insulators arguably remain the most poorly understood in their contribution to these processes in vivo. Indeed, our view of chromatin insulators has evolved dramatically since their chromatin boundary and enhancer blocking properties were elucidated roughly a quarter of a century ago as a result of recent genome-wide, high-throughput methods better suited to probing the role of these elements in their native genomic contexts. The overall theme that has emerged from these studies is that chromatin insulators function as general facilitators of higher-order chromatin loop structures that exert both physical and functional constraints on the genome. In this review, we summarize the result of recent work that supports this idea as well as a number of other studies linking these elements to a diverse array of nuclear processes, suggesting that chromatin insulators exert master control over genome organization and behavior.
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Affiliation(s)
- Todd Schoborg
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN 37996 USA
- Present Address: Laboratory of Molecular Machines and Tissue Architecture, Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, 50 South Dr Rm 2122, Bethesda, MD 20892 USA
| | - Mariano Labrador
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN 37996 USA
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Blackwell BJ, Lopez MF, Wang J, Krastins B, Sarracino D, Tollervey JR, Dobke M, Jordan IK, Lunyak VV. Protein interactions with piALU RNA indicates putative participation of retroRNA in the cell cycle, DNA repair and chromatin assembly. Mob Genet Elements 2014; 2:26-35. [PMID: 22754750 PMCID: PMC3383447 DOI: 10.4161/mge.19032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Recent analyses suggest that transposable element-derived transcripts are processed to yield a variety of small RNA species that play critical functional roles in gene regulation and chromatin organization as well as genome stability and maintenance. Here we report a mass spectrometry analysis of an RNA-affinity complex isolation using a piRNA homologous sequence derived from Alu retrotransposal RNA. Our data point to potential roles for piALU RNAs in DNA repair, cell cycle and chromatin regulations.
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A region of euchromatin coincides with an extensive tandem repeat on the mouse (Mus musculus) inactive X chromosome. Chromosome Res 2014; 22:335-50. [DOI: 10.1007/s10577-014-9424-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 04/15/2014] [Accepted: 04/16/2014] [Indexed: 12/18/2022]
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Court F, Camprubi C, Garcia CV, Guillaumet-Adkins A, Sparago A, Seruggia D, Sandoval J, Esteller M, Martin-Trujillo A, Riccio A, Montoliu L, Monk D. The PEG13-DMR and brain-specific enhancers dictate imprinted expression within the 8q24 intellectual disability risk locus. Epigenetics Chromatin 2014; 7:5. [PMID: 24667089 PMCID: PMC3986935 DOI: 10.1186/1756-8935-7-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 03/05/2014] [Indexed: 12/16/2022] Open
Abstract
Background Genomic imprinting is the epigenetic marking of genes that results in parent-of-origin monoallelic expression. Most imprinted domains are associated with differentially DNA methylated regions (DMRs) that originate in the gametes, and are maintained in somatic tissues after fertilization. This allelic methylation profile is associated with a plethora of histone tail modifications that orchestrates higher order chromatin interactions. The mouse chromosome 15 imprinted cluster contains multiple brain-specific maternally expressed transcripts including Ago2, Chrac1, Trappc9 and Kcnk9 and a paternally expressed gene, Peg13. The promoter of Peg13 is methylated on the maternal allele and is the sole DMR within the locus. To determine the extent of imprinting within the human orthologous region on chromosome 8q24, a region associated with autosomal recessive intellectual disability, Birk-Barel mental retardation and dysmorphism syndrome, we have undertaken a systematic analysis of allelic expression and DNA methylation of genes mapping within an approximately 2 Mb region around TRAPPC9. Results Utilizing allele-specific RT-PCR, bisulphite sequencing, chromatin immunoprecipitation and chromosome conformation capture (3C) we show the reciprocal expression of the novel, paternally expressed, PEG13 non-coding RNA and maternally expressed KCNK9 genes in brain, and the biallelic expression of flanking transcripts in a range of tissues. We identify a tandem-repeat region overlapping the PEG13 transcript that is methylated on the maternal allele, which binds CTCF-cohesin in chromatin immunoprecipitation experiments and possesses enhancer-blocker activity. Using 3C, we identify mutually exclusive approximately 58 and 500 kb chromatin loops in adult frontal cortex between a novel brain-specific enhancer, marked by H3K4me1 and H3K27ac, with the KCNK9 and PEG13 promoters which we propose regulates brain-specific expression. Conclusions We have characterised the molecular mechanism responsible for reciprocal allelic expression of the PEG13 and KCNK9 transcripts. Therefore, our observations may have important implications for identifying the cause of intellectual disabilities associated with the 8q24 locus.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - David Monk
- Imprinting and Cancer Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet de Llobregat, Barcelona 08907, Spain.
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Ichiyanagi K. Epigenetic regulation of transcription and possible functions of mammalian short interspersed elements, SINEs. Genes Genet Syst 2014; 88:19-29. [PMID: 23676707 DOI: 10.1266/ggs.88.19] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Short interspersed elements (SINEs) are a class of retrotransposons, which amplify their copy numbers in their host genomes by retrotransposition. More than a million copies of SINEs are present in a mammalian genome, constituting over 10% of the total genomic sequence. In contrast to the other two classes of retrotransposons, long interspersed elements (LINEs) and long terminal repeat (LTR) elements, SINEs are transcribed by RNA polymerase III. However, like LINEs and LTR elements, the SINE transcription is likely regulated by epigenetic mechanisms such as DNA methylation, at least for human Alu and mouse B1. Whereas SINEs and other transposable elements have long been thought as selfish or junk DNA, recent studies have revealed that they play functional roles at their genomic locations, for example, as distal enhancers, chromatin boundaries and binding sites of many transcription factors. These activities imply that SINE retrotransposition has shaped the regulatory network and chromatin landscape of their hosts. Whereas it is thought that the epigenetic mechanisms were originated as a host defense system against proliferation of parasitic elements, this review discusses a possibility that the same mechanisms are also used to regulate the SINE-derived functions.
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Affiliation(s)
- Kenji Ichiyanagi
- Division of Epigenomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
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Binding of TFIIIC to sine elements controls the relocation of activity-dependent neuronal genes to transcription factories. PLoS Genet 2013; 9:e1003699. [PMID: 23966877 PMCID: PMC3744447 DOI: 10.1371/journal.pgen.1003699] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 06/20/2013] [Indexed: 12/31/2022] Open
Abstract
In neurons, the timely and accurate expression of genes in response to synaptic activity relies on the interplay between epigenetic modifications of histones, recruitment of regulatory proteins to chromatin and changes to nuclear structure. To identify genes and regulatory elements responsive to synaptic activation in vivo, we performed a genome-wide ChIPseq analysis of acetylated histone H3 using somatosensory cortex of mice exposed to novel enriched environmental (NEE) conditions. We discovered that Short Interspersed Elements (SINEs) located distal to promoters of activity-dependent genes became acetylated following exposure to NEE and were bound by the general transcription factor TFIIIC. Importantly, under depolarizing conditions, inducible genes relocated to transcription factories (TFs), and this event was controlled by TFIIIC. Silencing of the TFIIIC subunit Gtf3c5 in non-stimulated neurons induced uncontrolled relocation to TFs and transcription of activity-dependent genes. Remarkably, in cortical neurons, silencing of Gtf3c5 mimicked the effects of chronic depolarization, inducing a dramatic increase of both dendritic length and branching. These findings reveal a novel and essential regulatory function of both SINEs and TFIIIC in mediating gene relocation and transcription. They also suggest that TFIIIC may regulate the rearrangement of nuclear architecture, allowing the coordinated expression of activity-dependent neuronal genes. In neurons, acetylation of histones and other epigenetic modifications influence gene expression in response to synaptic activity. Genes that are concomitantly expressed in response to stimulation are transcribed at specific nuclear foci, known as transcription factories (TFs) that are enriched with active RNA Polymerase II and often include specific transcription factors. Here, we show a novel regulatory role for Short Interspersed Elements (SINEs) located in the proximity of activity-regulated genes. SINEs represent a new class of regulatory sequences that function as coordinators of depolarization-dependent transcription. Binding of the general transcription factor TFIIIC to SINEs regulates activity-dependent transcription, relocation of inducible genes to transcription factories and dendritogenesis. Our study provides new fundamental insights into the mechanisms by which relocation of inducible genes to transcription factories and changes of nuclear architecture coordinate the transcriptional program in response to neuronal activity.
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Liu G, Mattick JS, Taft RJ. A meta-analysis of the genomic and transcriptomic composition of complex life. Cell Cycle 2013; 12:2061-72. [PMID: 23759593 DOI: 10.4161/cc.25134] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
It is now clear that animal genomes are predominantly non-protein-coding, and that these sequences encode a wide array of RNA transcripts and other regulatory elements that are fundamental to the development of complex life. We have previously argued that the proportion of an animal genome that is non-protein-coding DNA (ncDNA) correlates well with its apparent biological complexity. Here we extend on that work and, using data from a total of 1,627 prokaryotic and 153 eukaryotic complete and annotated genomes, show that the proportion of ncDNA per haploid genome is significantly positively correlated with a previously published proxy of biological complexity, the number of distinct cell types. This is in contrast to the amount of the genome that encodes proteins, which we show is essentially unchanged across Metazoa. Furthermore, using a total of 179 RNA-seq data sets from nematode (47), fruit fly (72), zebrafish (20) and human (42), we show, consistent with other recent reports, that the vast majority of ncDNA in animals is transcribed. This includes more than 60 human loci previously considered "gene deserts," many of which are expressed tissue-specifically and associated with previously reported GWAS SNPs. These results suggest that ncDNA, and the ncRNAs encoded within it, may be intimately involved in the evolution, maintenance and development of complex life.
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Affiliation(s)
- Ganqiang Liu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD Australia
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48
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de Souza FS, Franchini LF, Rubinstein M. Exaptation of transposable elements into novel cis-regulatory elements: is the evidence always strong? Mol Biol Evol 2013; 30:1239-51. [PMID: 23486611 PMCID: PMC3649676 DOI: 10.1093/molbev/mst045] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Transposable elements (TEs) are mobile genetic sequences that can jump around the genome from one location to another, behaving as genomic parasites. TEs have been particularly effective in colonizing mammalian genomes, and such heavy TE load is expected to have conditioned genome evolution. Indeed, studies conducted both at the gene and genome levels have uncovered TE insertions that seem to have been co-opted--or exapted--by providing transcription factor binding sites (TFBSs) that serve as promoters and enhancers, leading to the hypothesis that TE exaptation is a major factor in the evolution of gene regulation. Here, we critically review the evidence for exaptation of TE-derived sequences as TFBSs, promoters, enhancers, and silencers/insulators both at the gene and genome levels. We classify the functional impact attributed to TE insertions into four categories of increasing complexity and argue that so far very few studies have conclusively demonstrated exaptation of TEs as transcriptional regulatory regions. We also contend that many genome-wide studies dealing with TE exaptation in recent lineages of mammals are still inconclusive and that the hypothesis of rapid transcriptional regulatory rewiring mediated by TE mobilization must be taken with caution. Finally, we suggest experimental approaches that may help attributing higher-order functions to candidate exapted TEs.
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Affiliation(s)
- Flávio S.J. de Souza
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Lucía F. Franchini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Marcelo Rubinstein
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
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Rey-Barroso J, Colo GP, Alvarez-Barrientos A, Redondo-Muñoz J, Carvajal-González JM, Mulero-Navarro S, García-Pardo A, Teixidó J, Fernandez-Salguero PM. The dioxin receptor controls β1 integrin activation in fibroblasts through a Cbp–Csk–Src pathway. Cell Signal 2013; 25:848-59. [DOI: 10.1016/j.cellsig.2013.01.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 01/07/2013] [Accepted: 01/09/2013] [Indexed: 11/30/2022]
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50
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Rico-Leo EM, Alvarez-Barrientos A, Fernandez-Salguero PM. Dioxin receptor expression inhibits basal and transforming growth factor β-induced epithelial-to-mesenchymal transition. J Biol Chem 2013; 288:7841-7856. [PMID: 23382382 DOI: 10.1074/jbc.m112.425009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Recent studies have emphasized the role of the dioxin receptor (AhR) in maintaining cell morphology, adhesion, and migration. These novel AhR functions depend on the cell phenotype, and although AhR expression maintains mesenchymal fibroblasts migration, it inhibits keratinocytes motility. These observations prompted us to investigate whether AhR modulates the epithelial-to-mesenchymal transition (EMT). For this, we have used primary AhR(+/+) and AhR(-/-) keratinocytes and NMuMG cells engineered to knock down AhR levels (sh-AhR) or to express a constitutively active receptor (CA-AhR). Both AhR(-/-) keratinocytes and sh-AhR NMuMG cells had increased migration, reduced levels of epithelial markers E-cadherin and β-catenin, and increased expression of mesenchymal markers Snail, Slug/Snai2, vimentin, fibronectin, and α-smooth muscle actin. Consistently, AhR(+/+) and CA-AhR NMuMG cells had reduced migration and enhanced expression of epithelial markers. AhR activation by the agonist FICZ (6-formylindolo[3,2-b]carbazole) inhibited NMuMG migration, whereas the antagonist α-naphthoflavone induced migration as did AhR knockdown. Exogenous TGFβ exacerbated the promigratory mesenchymal phenotype in both AhR-expressing and AhR-depleted cells, although the effects on the latter were more pronounced. Rescuing AhR expression in sh-AhR cells reduced Snail and Slug/Snai2 levels and cell migration and restored E-cadherin levels. Interference of AhR in human HaCaT cells further supported its role in EMT. Interestingly, co-immunoprecipitation and immunofluorescence assays showed that AhR associates in common protein complexes with E-cadherin and β-catenin, suggesting the implication of AhR in cell-cell adhesion. Thus, basal or TGFβ-induced AhR down-modulation could be relevant in the acquisition of a motile EMT phenotype in both normal and transformed epithelial cells.
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Affiliation(s)
- Eva M Rico-Leo
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain
| | | | - Pedro M Fernandez-Salguero
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain.
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