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Abstract
Over the last decade, several theoretical models have been put forth to describe how animals respond to adverse environments and how this response changes under different physiological demands across life history stages. These models capture the context- and condition-dependent nature of stress responses. Yet, application of the models has been limited thus far in part because each model addresses different aspects of the problems facing the field of stress biology. Thus, there is a need for a unifying theoretical model that incorporates changes in physiological demand with life history stages and age, intricate relationships among physiological systems, and biphasic nature of stress responses. Here, I propose a new integrative framework, the Damage-Fitness Model. In this model, regulators, such as DNA repair mechanisms and glucocorticoids, work together as anti-damage mechanisms to minimize damage at both the cellular and organismal level. When the anti-damage regulators are insufficient or inappropriate, persistent damage accumulates. Previous studies indicate that these damage directly impact reproductive performance, disease risk, and survival. The types of regulators, the threshold at which they are initiated, and the magnitude of the responses are shaped by developmental and current environments. This model unites existing theoretical models by shifting our focus from physiological responses to downstream consequences of the stress responses, circumventing context specificity. Discussions include (1) how the proposed model relates to existing models, (2) steps to test the new model, and (3) how this model can be used to better assess the health of individuals and a population. Lay summary The field of stress physiology faces a challenge of characterizing dynamic cellular, physiological, and behavioral responses when animals encounter a stressor. This paper proposes a new theoretical model which links stress avoidance, damage repair and accumulation, and fitness components.
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Affiliation(s)
- Haruka Wada
- a Department of Biological Sciences, Auburn University , Auburn , AL , USA
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202
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Treger RS, Pope SD, Xing X, Iwasaki A. Application of a Modified Smart-seq2 Sample Preparation Protocol for Rare Cell Full-length Single-cell mRNA Sequencing to Mouse Oocytes. Bio Protoc 2019; 9:e3345. [PMID: 33654848 DOI: 10.21769/bioprotoc.3345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 07/22/2019] [Accepted: 07/24/2019] [Indexed: 11/02/2022] Open
Abstract
Endogenous retroviruses (ERV) are transposable retroelements that form ~10% of the murine genome and whose family members are differentially expressed throughout embryogenesis. However, precise regulation of ERV in germ cells remains unclear. To investigate ERV expression in oocytes, we adapted a single-cell mRNA-sequencing library preparation method to generate bulk sequencing libraries from growing oocytes in a time- and cost-efficient manner. Here, we present a modified Smart-seq2 protocol that yields full-length cDNA libraries from purified RNA obtained from low numbers of pooled immature or mature oocytes. Using this method, RNA-sequencing libraries can be generated from any rare or difficult-to-isolate populations for subsequent sequencing and retroelement expression analysis.
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Affiliation(s)
- Rebecca S Treger
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Scott D Pope
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Xiaojun Xing
- Yale Genome Editing Center, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Akiko Iwasaki
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA.,Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
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203
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Puurand T, Kukuškina V, Pajuste FD, Remm M. AluMine: alignment-free method for the discovery of polymorphic Alu element insertions. Mob DNA 2019; 10:31. [PMID: 31360240 PMCID: PMC6639938 DOI: 10.1186/s13100-019-0174-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 07/12/2019] [Indexed: 01/09/2023] Open
Abstract
Background Recently, alignment-free sequence analysis methods have gained popularity in the field of personal genomics. These methods are based on counting frequencies of short k-mer sequences, thus allowing faster and more robust analysis compared to traditional alignment-based methods. Results We have created a fast alignment-free method, AluMine, to analyze polymorphic insertions of Alu elements in the human genome. We tested the method on 2,241 individuals from the Estonian Genome Project and identified 28,962 potential polymorphic Alu element insertions. Each tested individual had on average 1,574 Alu element insertions that were different from those in the reference genome. In addition, we propose an alignment-free genotyping method that uses the frequency of insertion/deletion-specific 32-mer pairs to call the genotype directly from raw sequencing reads. Using this method, the concordance between the predicted and experimentally observed genotypes was 98.7%. The running time of the discovery pipeline is approximately 2 h per individual. The genotyping of potential polymorphic insertions takes between 0.4 and 4 h per individual, depending on the hardware configuration. Conclusions AluMine provides tools that allow discovery of novel Alu element insertions and/or genotyping of known Alu element insertions from personal genomes within few hours.
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Affiliation(s)
- Tarmo Puurand
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Viktoria Kukuškina
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | | | - Maido Remm
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
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204
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Lieber MR. Transposons to V(D)J Recombination: Evolution of the RAG Reaction. Trends Immunol 2019; 40:668-670. [PMID: 31307890 DOI: 10.1016/j.it.2019.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 06/25/2019] [Indexed: 11/28/2022]
Abstract
Evolutionarily, how RAG endonucleases in vertebrate immune systems could shed dangerous transposon-like propensities, and instead, support the organized assembly of antigen receptor variable domains, has been unclear. Recent structural work by Schatz and colleagues (Nature, 2019) identifies features of the RAG endonuclease deemed to be key in supporting this critical change in vertebrate advancement.
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Affiliation(s)
- Michael R Lieber
- University of Southern California, Los Angeles, CA 90089-9176, USA.
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205
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Chatron N, Cassinari K, Quenez O, Baert-Desurmont S, Bardel C, Buisine MP, Calpena E, Capri Y, Corominas Galbany J, Diguet F, Edery P, Isidor B, Labalme A, Le Caignec C, Lévy J, Lecoquierre F, Lindenbaum P, Pichon O, Rollat-Farnier PA, Simonet T, Saugier-Veber P, Tabet AC, Toutain A, Wilkie AOM, Lesca G, Sanlaville D, Nicolas G, Schluth-Bolard C. Identification of mobile retrocopies during genetic testing: Consequences for routine diagnosis. Hum Mutat 2019; 40:1993-2000. [PMID: 31230393 DOI: 10.1002/humu.23845] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 05/29/2019] [Accepted: 06/17/2019] [Indexed: 12/24/2022]
Abstract
Human retrocopies, that is messenger RNA transcripts benefitting from the long interspersed element 1 machinery for retrotransposition, may have specific consequences for genomic testing. Next genetration sequencing (NGS) techniques allow the detection of such mobile elements but they may be misinterpreted as genomic duplications or be totally overlooked. We report eight observations of retrocopies detected during diagnostic NGS analyses of targeted gene panels, exome, or genome sequencing. For seven cases, while an exons-only copy number gain was called, read alignment inspection revealed a depth of coverage shift at every exon-intron junction where indels were also systematically called. Moreover, aberrant chimeric read pairs spanned entire introns or were paired with another locus for terminal exons. The 8th retrocopy was present in the reference genome and thus showed a normal NGS profile. We emphasize the existence of retrocopies and strategies to accurately detect them at a glance during genetic testing and discuss pitfalls for genetic testing.
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Affiliation(s)
- Nicolas Chatron
- Genetics Department, Hospices Civils de Lyon, Lyon, France.,GENDEV Team, CRNL, INSERM U1028, CNRS UMR5292, UCBL1, Lyon, France
| | - Kevin Cassinari
- Department of Genetics and CNR-MAJ, Normandie Univ, UNIROUEN, Inserm U1245 and Rouen University Hospital, F 76000, Normandy Center for Genomic and Personalized Medicine, Rouen, France
| | - Olivier Quenez
- Department of Genetics and CNR-MAJ, Normandie Univ, UNIROUEN, Inserm U1245 and Rouen University Hospital, F 76000, Normandy Center for Genomic and Personalized Medicine, Rouen, France
| | - Stéphanie Baert-Desurmont
- Department of Genetics, Normandie Univ, UNIROUEN, Inserm U1245 and Rouen University Hospital, F 76000, Normandy Center for Genomic and Personalized Medicine, Rouen, France
| | - Claire Bardel
- Bioinformatics group of the Lyon University Hospital NGS facility, Groupement Hospitalier Est, Lyon, France.,Biostatistics and Bioinformatics Department, HCL, Lyon, France
| | - Marie-Pierre Buisine
- Department of Biochemistry and Molecular Biology, JPA Research Center, Inserm UMR-S 1172, Lille University, Lille University Hospital, Lille, France
| | - Eduardo Calpena
- Clinical Genetics Group, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Yline Capri
- Genetics Department, Clinical Genetics Unit, Hôpital Universitaire Robert Debré, Paris, France
| | | | - Flavie Diguet
- Genetics Department, Hospices Civils de Lyon, Lyon, France.,GENDEV Team, CRNL, INSERM U1028, CNRS UMR5292, UCBL1, Lyon, France
| | - Patrick Edery
- Genetics Department, Hospices Civils de Lyon, Lyon, France.,GENDEV Team, CRNL, INSERM U1028, CNRS UMR5292, UCBL1, Lyon, France
| | | | - Audrey Labalme
- Genetics Department, Hospices Civils de Lyon, Lyon, France
| | - Cedric Le Caignec
- Genetics Department, CHU Nantes, Nantes, France.,INSERM UMR_S915, Institut du thorax, Nantes University, Nantes, France
| | - Jonathan Lévy
- Genetics Department, Cytogenetics Unit, Hôpital Universitaire Robert Debré, Paris, France
| | - François Lecoquierre
- Department of Genetics, Normandie Univ, UNIROUEN, Inserm U1245 and Rouen University Hospital, F 76000, Normandy Center for Genomic and Personalized Medicine, Rouen, France
| | - Pierre Lindenbaum
- INSERM, UMR_S1087, Institut du thorax, Nantes, France.,CNRS, UMR 6291, Nantes, France
| | | | - Pierre-Antoine Rollat-Farnier
- Genetics Department, Hospices Civils de Lyon, Lyon, France.,Bioinformatics group of the Lyon University Hospital NGS facility, Groupement Hospitalier Est, Lyon, France
| | - Thomas Simonet
- Cellular Biotechnology Center, Hospices Civils de Lyon, Lyon, France.,Nerve-Muscle Interactions Team, Institut NeuroMyoGène CNRS UMR 5310-INSERM U1217-Université Claude Bernard Lyon 1, Lyon, France
| | - Pascale Saugier-Veber
- Department of Genetics, Normandie Univ, UNIROUEN, Inserm U1245 and Rouen University Hospital, F 76000, Normandy Center for Genomic and Personalized Medicine, Rouen, France
| | - Anne-Claude Tabet
- Genetics Department, Cytogenetics Unit, Hôpital Universitaire Robert Debré, Paris, France.,Neuroscience Department, Human Genetics and Cognitive Function Unit, Institut Pasteur, Paris, France
| | - Annick Toutain
- Genetics Department, Hôpital Bretonneau, CHU, Tours, France.,UMR 1253, iBrain, Tours University, Inserm, Tours, France
| | - Andrew O M Wilkie
- Clinical Genetics Group, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Gaetan Lesca
- Genetics Department, Hospices Civils de Lyon, Lyon, France.,GENDEV Team, CRNL, INSERM U1028, CNRS UMR5292, UCBL1, Lyon, France
| | - Damien Sanlaville
- Genetics Department, Hospices Civils de Lyon, Lyon, France.,GENDEV Team, CRNL, INSERM U1028, CNRS UMR5292, UCBL1, Lyon, France
| | - Gaël Nicolas
- Department of Genetics and CNR-MAJ, Normandie Univ, UNIROUEN, Inserm U1245 and Rouen University Hospital, F 76000, Normandy Center for Genomic and Personalized Medicine, Rouen, France
| | - Caroline Schluth-Bolard
- Genetics Department, Hospices Civils de Lyon, Lyon, France.,GENDEV Team, CRNL, INSERM U1028, CNRS UMR5292, UCBL1, Lyon, France
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206
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Nabel CS, Sameroff S, Shilling D, Alapat D, Ruth JR, Kawano M, Sato Y, Stone K, Spetalen S, Valdivieso F, Feldman MD, Chadburn A, Fosså A, van Rhee F, Lipkin WI, Fajgenbaum DC. Virome capture sequencing does not identify active viral infection in unicentric and idiopathic multicentric Castleman disease. PLoS One 2019; 14:e0218660. [PMID: 31242229 PMCID: PMC6594611 DOI: 10.1371/journal.pone.0218660] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 06/06/2019] [Indexed: 01/09/2023] Open
Abstract
Castleman disease (CD) describes a spectrum of heterogeneous disorders defined by characteristic lymph node histopathology. Enlarged lymph nodes demonstrating CD histopathology can occur in isolation (unicentric CD; UCD) sometimes accompanied by mild symptoms, or at multiple sites (multicentric CD, MCD) with systemic inflammation and cytokine-driven multi-organ dysfunction. The discovery that Kaposi sarcoma herpesvirus/human herpesvirus (HHV)-8 drives MCD in a subset of patients has led to the hypotheses that UCD and MCD patients with negative HHV-8 testing by conventional methods may represent false negatives, or that these cases are driven by another virus, known or unknown. To investigate these hypotheses, the virome capture sequencing for vertebrate viruses (VirCapSeq-VERT) platform was employed to detect RNA transcripts from known and novel viruses in fresh frozen lymph node tissue from CD patients (12 UCD, 11 HHV-8-negative MCD [idiopathic MCD; iMCD], and two HHV-8-positive MCD) and related diseases (three T cell lymphoma and three Hodgkin lymphoma). This assay detected HHV-8 in both HHV-8-positive cases; however, HHV-8 was not found in clinically HHV-8-negative iMCD or UCD cases. Additionally, no novel viruses were discovered, and no single known virus was detected with apparent association to HHV-8-negative CD cases. Herpesviridae family members, notably including Epstein-Barr virus (EBV), were detected in 7 out of 12 UCD and 5 of 11 iMCD cases with apparent correlations with markers of disease severity in iMCD. Analysis of a separate cohort of archival formalin-fixed, paraffin-embedded lymph node tissue by In situ hybridization revealed significantly fewer EBV-positive cells in UCD and iMCD compared to tissue from HHV-8-positive MCD and EBV-associated lymphoproliferative disorder. In an additional cohort, quantitative testing for EBV by PCR in peripheral blood during disease flare did not detect systemic EBV viremia, suggesting detection lymph node tissue is due to occult, local reactivation in UCD and iMCD. This study confirms that HHV-8 is not present in UCD and iMCD patients. Further, it fails to establish a clear association between any single virus, novel or known, and CD in HHV-8-negative cases. Given that distinct forms of CD exist with viral and non-viral etiological drivers, CD should be considered a group of distinct and separate diseases with heterogeneous causes worthy of further study.
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Affiliation(s)
- Christopher S. Nabel
- Dana-Farber Cancer Institute, Massachusetts General Hospital Cancer Center, Boston, Massachusetts, United States of America
| | - Stephen Sameroff
- Columbia University, New York, New York, United States of America
| | - Dustin Shilling
- Castleman Disease Collaborative Network, Philadelphia, Pennsylvania, United States of America
| | - Daisy Alapat
- Myeloma Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Jason R. Ruth
- Castleman Disease Collaborative Network, Philadelphia, Pennsylvania, United States of America
| | | | - Yasuharu Sato
- Division of Pathophysiology, Okayama University Graduate School of Health Sciences, Okayama, Japan
| | - Katie Stone
- Myeloma Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | | | - Federico Valdivieso
- Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Michael D. Feldman
- Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Amy Chadburn
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, United States of America
| | | | - Frits van Rhee
- Myeloma Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - W. Ian Lipkin
- Columbia University, New York, New York, United States of America
| | - David C. Fajgenbaum
- Castleman Disease Collaborative Network, Philadelphia, Pennsylvania, United States of America
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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207
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Sanchez-Luque FJ, Kempen MJHC, Gerdes P, Vargas-Landin DB, Richardson SR, Troskie RL, Jesuadian JS, Cheetham SW, Carreira PE, Salvador-Palomeque C, García-Cañadas M, Muñoz-Lopez M, Sanchez L, Lundberg M, Macia A, Heras SR, Brennan PM, Lister R, Garcia-Perez JL, Ewing AD, Faulkner GJ. LINE-1 Evasion of Epigenetic Repression in Humans. Mol Cell 2019; 75:590-604.e12. [PMID: 31230816 DOI: 10.1016/j.molcel.2019.05.024] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 04/08/2019] [Accepted: 05/15/2019] [Indexed: 02/07/2023]
Abstract
Epigenetic silencing defends against LINE-1 (L1) retrotransposition in mammalian cells. However, the mechanisms that repress young L1 families and how L1 escapes to cause somatic genome mosaicism in the brain remain unclear. Here we report that a conserved Yin Yang 1 (YY1) transcription factor binding site mediates L1 promoter DNA methylation in pluripotent and differentiated cells. By analyzing 24 hippocampal neurons with three distinct single-cell genomic approaches, we characterized and validated a somatic L1 insertion bearing a 3' transduction. The source (donor) L1 for this insertion was slightly 5' truncated, lacked the YY1 binding site, and was highly mobile when tested in vitro. Locus-specific bisulfite sequencing revealed that the donor L1 and other young L1s with mutated YY1 binding sites were hypomethylated in embryonic stem cells, during neurodifferentiation, and in liver and brain tissue. These results explain how L1 can evade repression and retrotranspose in the human body.
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Affiliation(s)
- Francisco J Sanchez-Luque
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia; GENYO Centre for Genomics and Oncological Research, Pfizer University of Granada, Andalusian Regional Government, Avda Ilustración, 114, PTS Granada 18016, Spain.
| | - Marie-Jeanne H C Kempen
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia; MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine (IGMM), University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Patricia Gerdes
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Dulce B Vargas-Landin
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, the University of Western Australia, Perth, WA 6009, Australia; Harry Perkins Institute of Medical Research, Perth, WA 6009, Australia
| | - Sandra R Richardson
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Robin-Lee Troskie
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - J Samuel Jesuadian
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Seth W Cheetham
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Patricia E Carreira
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Carmen Salvador-Palomeque
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Marta García-Cañadas
- GENYO Centre for Genomics and Oncological Research, Pfizer University of Granada, Andalusian Regional Government, Avda Ilustración, 114, PTS Granada 18016, Spain
| | - Martin Muñoz-Lopez
- GENYO Centre for Genomics and Oncological Research, Pfizer University of Granada, Andalusian Regional Government, Avda Ilustración, 114, PTS Granada 18016, Spain
| | - Laura Sanchez
- GENYO Centre for Genomics and Oncological Research, Pfizer University of Granada, Andalusian Regional Government, Avda Ilustración, 114, PTS Granada 18016, Spain
| | - Mischa Lundberg
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Angela Macia
- Department of Pediatrics/Rady Children's Hospital San Diego, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Sara R Heras
- GENYO Centre for Genomics and Oncological Research, Pfizer University of Granada, Andalusian Regional Government, Avda Ilustración, 114, PTS Granada 18016, Spain; Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, 18071 Granada, Spain
| | - Paul M Brennan
- Edinburgh Cancer Research Centre, Western General Hospital, Edinburgh, EH4 2XR, UK
| | - Ryan Lister
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, the University of Western Australia, Perth, WA 6009, Australia; Harry Perkins Institute of Medical Research, Perth, WA 6009, Australia
| | - Jose L Garcia-Perez
- GENYO Centre for Genomics and Oncological Research, Pfizer University of Granada, Andalusian Regional Government, Avda Ilustración, 114, PTS Granada 18016, Spain; MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine (IGMM), University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Adam D Ewing
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia
| | - Geoffrey J Faulkner
- Mater Research Institute, University of Queensland, TRI Building, Woolloongabba, QLD 4102, Australia; Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia.
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208
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Lapp HE, Hunter RG. Early life exposures, neurodevelopmental disorders, and transposable elements. Neurobiol Stress 2019; 11:100174. [PMID: 31193573 PMCID: PMC6536887 DOI: 10.1016/j.ynstr.2019.100174] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 03/27/2019] [Accepted: 05/21/2019] [Indexed: 12/26/2022] Open
Abstract
Transposable elements make up a much larger portion of the genome than protein-coding genes, yet we know relatively little about their function in the human genome. However, we are beginning to more fully understand their role in brain development, neuroinflammation, and adaptation to environmental insults such as stress. For instance, glucocorticoid receptor activation regulates transposable elements in the brain following acute stress. Early life is a period of substantial brain development during which transposable elements play a role. Environmental exposures and experiences during early life that promote abnormal regulation of transposable elements may lead to a cascade of events that ultimately increase susceptibility to disorders later in life. Recent attention to transposable elements in psychiatric illness has begun to clarify associations indicative of dysregulation of different classes of transposable elements in stress-related and neurodevelopmental illness. Though individual susceptibility or resiliency to psychiatric illness has not been explained by traditional genetic studies, the wide inter-individual variability in transposable element composition in the human genome make TEs attractive candidates to elucidate this differential susceptibility. In this review, we discuss evidence that regulation of transposable elements in the brain are stage-specific, sensitive to environmental factors, and may be impacted by early life perturbations. We further present evidence of associations with stress-related and neurodevelopmental psychiatric illness from a developmental perspective.
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Affiliation(s)
- Hannah E Lapp
- University of Massachusetts Boston, 100 Morrissey Blvd Boston, MA, 02125, USA
| | - Richard G Hunter
- University of Massachusetts Boston, 100 Morrissey Blvd Boston, MA, 02125, USA
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209
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Aberrant expression of select piRNA-pathway genes does not reactivate piRNA silencing in cancer cells. Proc Natl Acad Sci U S A 2019; 116:11111-11112. [PMID: 31110013 PMCID: PMC6561285 DOI: 10.1073/pnas.1904498116] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Germline genes that are aberrantly expressed in nongermline cancer cells have the potential to be ideal targets for diagnosis and therapy due to their restricted physiological expression, their broad reactivation in various cancer types, and their immunogenic properties. Among such cancer/testis genes, components of the PIWI-interacting small RNA (piRNA) pathway are of particular interest, as they control mobile genetic elements (transposons) in germ cells and thus hold great potential to counteract genome instability in cancer. Here, we systematically investigate the potential reactivation of functional piRNA-silencing mechanisms in the aberrant context. While we observe expression of individual piRNA-pathway genes in cancer, we fail to detect the formation of functional piRNA-silencing complexes. Accordingly, the expression of a PIWI protein alone remains inconsequential to the cancer cell transcriptome. Our data provide a framework for the investigation of complex aberrant gene-expression signatures and establish that reactivation of piRNA silencing, if at all, is not a prevalent phenomenon in cancer cells.
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210
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Kim S, Ku Y, Ku J, Kim Y. Evidence of Aberrant Immune Response by Endogenous Double-Stranded RNAs: Attack from Within. Bioessays 2019; 41:e1900023. [PMID: 31099409 DOI: 10.1002/bies.201900023] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/15/2019] [Indexed: 12/17/2022]
Abstract
Many innate immune response proteins recognize foreign nucleic acids from invading pathogens to initiate antiviral signaling. These proteins mostly rely on structural characteristics of the nucleic acids rather than their specific sequences to distinguish self and nonself. One feature utilized by RNA sensors is the extended stretch of double-stranded RNA (dsRNA) base pairs. However, the criteria for recognizing nonself dsRNAs are rather lenient, and hairpin structure of self-RNAs can also trigger an immune response. Consequently, aberrant activation of RNA sensors has been reported in numerous human diseases. Yet, in most cases, the activating antigens remain unknown. Recent studies have developed sequencing techniques tailored to specifically capture dsRNAs and identified that various noncoding elements in the nuclear and the mitochondrial genome can generate dsRNAs. Here, the identity of endogenous dsRNAs, their recognition by dsRNA sensors, and their implications in the pathogenesis of human diseases ranging from inflammatory to degenerative are presented.
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Affiliation(s)
- Sujin Kim
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,KI for Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Yongsuk Ku
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,KI for Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Jayoung Ku
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,KI for Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Yoosik Kim
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,KI for Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
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211
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Abstract
Primordial germ cells (PGCs) must complete a complex and dynamic developmental program during embryogenesis to establish the germline. This process is highly conserved and involves a diverse array of tasks required of PGCs, including migration, survival, sex differentiation, and extensive epigenetic reprogramming. A common theme across many organisms is that PGC success is heterogeneous: only a portion of all PGCs complete all these steps while many other PGCs are eliminated from further germline contribution. The differences that distinguish successful PGCs as a population are not well understood. Here, we examine variation that exists in PGCs as they navigate the many stages of this developmental journey. We explore potential sources of PGC heterogeneity and their potential implications in affecting germ cell behaviors. Lastly, we discuss the potential for PGC development to function as a multistage selection process that assesses heterogeneity in PGCs to refine germline quality.
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Affiliation(s)
- Daniel H Nguyen
- Department of Obstetrics, Gynecology and Reproductive Science, Center for Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, United States
| | - Rebecca G Jaszczak
- Department of Obstetrics, Gynecology and Reproductive Science, Center for Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, United States
| | - Diana J Laird
- Department of Obstetrics, Gynecology and Reproductive Science, Center for Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, United States.
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Hardy MP, Audemard É, Migneault F, Feghaly A, Brochu S, Gendron P, Boilard É, Major F, Dieudé M, Hébert MJ, Perreault C. Apoptotic endothelial cells release small extracellular vesicles loaded with immunostimulatory viral-like RNAs. Sci Rep 2019; 9:7203. [PMID: 31076589 PMCID: PMC6510763 DOI: 10.1038/s41598-019-43591-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 04/26/2019] [Indexed: 02/07/2023] Open
Abstract
Endothelial cells have multifaceted interactions with the immune system, both as initiators and targets of immune responses. In vivo, apoptotic endothelial cells release two types of extracellular vesicles upon caspase-3 activation: apoptotic bodies and exosome-like nanovesicles (ApoExos). Only ApoExos are immunogenic: their injection causes inflammation and autoimmunity in mice. Based on deep sequencing of total RNA, we report that apoptotic bodies and ApoExos are loaded with divergent RNA cargos that are not released by healthy endothelial cells. Apoptotic bodies, like endothelial cells, contain mainly ribosomal RNA whereas ApoExos essentially contain non-ribosomal non-coding RNAs. Endogenous retroelements, bearing viral-like features, represented half of total ApoExos RNA content. ApoExos also contained several copies of unedited Alu repeats and large amounts of non-coding RNAs with a demonstrated role in autoimmunity such as U1 RNA and Y RNA. Moreover, ApoExos RNAs had a unique nucleotide composition and secondary structure characterized by strong enrichment in U-rich motifs and unstably folded RNAs. Globally, ApoExos were therefore loaded with RNAs that can stimulate a variety of RIG-I-like receptors and endosomal TLRs. Hence, apoptotic endothelial cells selectively sort in ApoExos a diversified repertoire of immunostimulatory "self RNAs" that are tailor-made for initiation of innate immune responses and autoimmunity.
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Affiliation(s)
- Marie-Pierre Hardy
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC, H3C 3J7, Canada
- Canadian National Transplant Research Program, Edmonton, Alberta, T6G 2E1, Canada
| | - Éric Audemard
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC, H3C 3J7, Canada
| | - Francis Migneault
- Canadian National Transplant Research Program, Edmonton, Alberta, T6G 2E1, Canada
- Research Centre, Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada
| | - Albert Feghaly
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC, H3C 3J7, Canada
| | - Sylvie Brochu
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC, H3C 3J7, Canada
- Canadian National Transplant Research Program, Edmonton, Alberta, T6G 2E1, Canada
| | - Patrick Gendron
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC, H3C 3J7, Canada
| | - Éric Boilard
- Canadian National Transplant Research Program, Edmonton, Alberta, T6G 2E1, Canada
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, Faculté de Médecine de l'Université Laval, Québec, Québec, Canada
| | - François Major
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC, H3C 3J7, Canada
- Department of Computer Science and Operations Research, Université de Montréal, Montreal, QC, H3C 3J7, Canada
- Department of Biochemistry, Faculty of Medicine, Université de Montréal, Montreal, QC, H3C 3J7, Canada
| | - Mélanie Dieudé
- Canadian National Transplant Research Program, Edmonton, Alberta, T6G 2E1, Canada
- Research Centre, Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada
| | - Marie-Josée Hébert
- Canadian National Transplant Research Program, Edmonton, Alberta, T6G 2E1, Canada
- Research Centre, Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada
- Department of Medicine, Université de Montréal, Montreal, QC, H3C 3J7, Canada
| | - Claude Perreault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC, H3C 3J7, Canada.
- Canadian National Transplant Research Program, Edmonton, Alberta, T6G 2E1, Canada.
- Department of Medicine, Université de Montréal, Montreal, QC, H3C 3J7, Canada.
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213
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Wang Z, McSwiggin H, Newkirk SJ, Wang Y, Oliver D, Tang C, Lee S, Wang S, Yuan S, Zheng H, Ye P, An W, Yan W. Insertion of a chimeric retrotransposon sequence in mouse Axin1 locus causes metastable kinky tail phenotype. Mob DNA 2019; 10:17. [PMID: 31073336 PMCID: PMC6500023 DOI: 10.1186/s13100-019-0162-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 04/21/2019] [Indexed: 12/12/2022] Open
Abstract
Background Transposable elements (TEs) make up > 50% of the human genome, and the majority of retrotransposon insertions are truncated and many are located in introns. However, the effects of retrotransposition on the host genes remain incompletely known. Results We report here that insertion of a chimeric L1 (cL1), but not IAP solo LTR, into intron 6 of Axin1 using CRIPSR/Cas9 induced the kinky tail phenotype with ~ 80% penetrance in heterozygous Axin cL1 mice. Both penetrant (with kinky tails) and silent (without kinky tails) Axin cL1 mice, regardless of sex, could transmit the phenotype to subsequent generations with similar penetrance (~ 80%). Further analyses revealed that a longer Axin1 transcript isoform containing partial cL1-targeted intron was present in penetrant, but absent in silent and wild type mice, and the production of this unique Axin1 transcript appeared to correlate with altered levels of an activating histone modification, H3K9ac. Conclusions The mechanism for Axin cL1 mice is different from those previously identified in mice with spontaneous retrotransposition of IAP, e.g., Axin Fu and A vy , both of which have been associated with DNA methylation changes. Our data suggest that Axin1 locus is sensitive to genetic and epigenetic alteration by retrotransposons and thus, ideally suited for studying the effects of new retrotransposition events on target gene function in mice.
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Affiliation(s)
- Zhuqing Wang
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Hayden McSwiggin
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Simon J Newkirk
- 3Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007 USA
| | - Yue Wang
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Daniel Oliver
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Chong Tang
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Sandy Lee
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Shawn Wang
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Shuiqiao Yuan
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Huili Zheng
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA
| | - Ping Ye
- 2Avera McKennan Hospital and University Health Center, Sioux Falls, SD 57108 USA.,3Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007 USA
| | - Wenfeng An
- 3Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007 USA
| | - Wei Yan
- 1Department of Physiology and Cell Biology, University of Nevada School of Medicine Center for Molecular Medicine, Room 207B 1664 North Virginia Street MS/0575, Reno, NV 89557 USA.,4Department of Obstetrics and Gynecology, University of Nevada, Reno School of Medicine, Reno, NV 89557 USA.,5Department of Biology, University of Nevada, Reno, Reno, NV 89557 USA
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214
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Chang YH, Keegan RM, Prazak L, Dubnau J. Cellular labeling of endogenous retrovirus replication (CLEVR) reveals de novo insertions of the gypsy retrotransposable element in cell culture and in both neurons and glial cells of aging fruit flies. PLoS Biol 2019; 17:e3000278. [PMID: 31095565 PMCID: PMC6541305 DOI: 10.1371/journal.pbio.3000278] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 05/29/2019] [Accepted: 05/03/2019] [Indexed: 12/11/2022] Open
Abstract
Evidence is rapidly mounting that transposable element (TE) expression and replication may impact biology more widely than previously thought. This includes potential effects on normal physiology of somatic tissues and dysfunctional impacts in diseases associated with aging, such as cancer and neurodegeneration. Investigation of the biological impact of mobile elements in somatic cells will be greatly facilitated by the use of donor elements that are engineered to report de novo events in vivo. In multicellular organisms, reporter constructs demonstrating engineered long interspersed nuclear element (LINE-1; L1) mobilization have been in use for quite some time, and strategies similar to L1 retrotransposition reporter assays have been developed to report replication of Ty1 elements in yeast and mouse intracisternal A particle (IAP) long terminal repeat (LTR) retrotransposons in cultivated cells. We describe a novel approach termed cellular labeling of endogenous retrovirus replication (CLEVR), which reports replication of the gypsy element within specific cells in vivo in Drosophila. The gypsy-CLEVR reporter reveals gypsy replication both in cell culture and in individual neurons and glial cells of the aging adult fly. We also demonstrate that the gypsy-CLEVR replication rate is increased when the short interfering RNA (siRNA) silencing system is genetically disrupted. This CLEVR strategy makes use of universally conserved features of retroviruses and should be widely applicable to other LTR retrotransposons, endogenous retroviruses (ERVs), and exogenous retroviruses.
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Affiliation(s)
- Yung-Heng Chang
- Department of Anesthesiology, Stony Brook School of Medicine, Stony Brook, New York, United States of America
| | - Richard M. Keegan
- Program in Neuroscience, Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York, United States of America
| | - Lisa Prazak
- Biology, Farmingdale State College, Farmingdale, New York, United States of America
| | - Josh Dubnau
- Department of Anesthesiology, Stony Brook School of Medicine, Stony Brook, New York, United States of America
- Program in Neuroscience, Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York, United States of America
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215
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Gagnier L, Belancio VP, Mager DL. Mouse germ line mutations due to retrotransposon insertions. Mob DNA 2019; 10:15. [PMID: 31011371 PMCID: PMC6466679 DOI: 10.1186/s13100-019-0157-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/01/2019] [Indexed: 12/24/2022] Open
Abstract
Transposable element (TE) insertions are responsible for a significant fraction of spontaneous germ line mutations reported in inbred mouse strains. This major contribution of TEs to the mutational landscape in mouse contrasts with the situation in human, where their relative contribution as germ line insertional mutagens is much lower. In this focussed review, we provide comprehensive lists of TE-induced mouse mutations, discuss the different TE types involved in these insertional mutations and elaborate on particularly interesting cases. We also discuss differences and similarities between the mutational role of TEs in mice and humans.
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Affiliation(s)
- Liane Gagnier
- Terry Fox Laboratory, BC Cancer and Department of Medical Genetics, University of British Columbia, V5Z1L3, Vancouver, BC Canada
| | - Victoria P. Belancio
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112 USA
| | - Dixie L. Mager
- Terry Fox Laboratory, BC Cancer and Department of Medical Genetics, University of British Columbia, V5Z1L3, Vancouver, BC Canada
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216
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Somatic LINE-1 retrotransposition in cortical neurons and non-brain tissues of Rett patients and healthy individuals. PLoS Genet 2019; 15:e1008043. [PMID: 30973874 PMCID: PMC6478352 DOI: 10.1371/journal.pgen.1008043] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 04/23/2019] [Accepted: 02/21/2019] [Indexed: 11/19/2022] Open
Abstract
Mounting evidence supports that LINE-1 (L1) retrotransposition can occur postzygotically in healthy and diseased human tissues, contributing to genomic mosaicism in the brain and other somatic tissues of an individual. However, the genomic distribution of somatic human-specific LINE-1 (L1Hs) insertions and their potential impact on carrier cells remain unclear. Here, using a PCR-based targeted bulk sequencing approach, we profiled 9,181 somatic insertions from 20 postmortem tissues from five Rett patients and their matched healthy controls. We identified and validated somatic L1Hs insertions in both cortical neurons and non-brain tissues. In Rett patients, somatic insertions were significantly depleted in exons—mainly contributed by long genes—than healthy controls, implying that cells carrying MECP2 mutations might be defenseless against a second exonic L1Hs insertion. We observed a significant increase of somatic L1Hs insertions in the brain compared with non-brain tissues from the same individual. Compared to germline insertions, somatic insertions were less sense-depleted to transcripts, indicating that they underwent weaker selective pressure on the orientation of insertion. Our observations demonstrate that somatic L1Hs insertions contribute to genomic diversity and MeCP2 dysfunction alters their genomic patterns in Rett patients. Human-specific LINE-1 (L1Hs) is the most active autonomous retrotransposon family in the human genome. Mounting evidence supports that L1Hs retrotransposition occurs postzygotically in the human brain cells, contributing to neuronal genomic diversity, but the extent of L1Hs-driven mosaicism in the brain is debated. In this study, we profiled genome-wide L1Hs insertions among 20 postmortem tissues from Rett patients and matched controls. We identified and validated somatic L1Hs insertions in both cortical neurons and non-brain tissues, with a higher jumping activity in the brain. We further found that MeCP2 dysfunction might alter the genomic pattern of somatic L1Hs in Rett patients.
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217
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Sultana T, van Essen D, Siol O, Bailly-Bechet M, Philippe C, Zine El Aabidine A, Pioger L, Nigumann P, Saccani S, Andrau JC, Gilbert N, Cristofari G. The Landscape of L1 Retrotransposons in the Human Genome Is Shaped by Pre-insertion Sequence Biases and Post-insertion Selection. Mol Cell 2019; 74:555-570.e7. [PMID: 30956044 DOI: 10.1016/j.molcel.2019.02.036] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 01/28/2019] [Accepted: 02/25/2019] [Indexed: 01/10/2023]
Abstract
L1 retrotransposons are transposable elements and major contributors of genetic variation in humans. Where L1 integrates into the genome can directly impact human evolution and disease. Here, we experimentally induced L1 retrotransposition in cells and mapped integration sites at nucleotide resolution. At local scales, L1 integration is mostly restricted by genome sequence biases and the specificity of the L1 machinery. At regional scales, L1 shows a broad capacity for integration into all chromatin states, in contrast to other known mobile genetic elements. However, integration is influenced by the replication timing of target regions, suggesting a link to host DNA replication. The distribution of new L1 integrations differs from those of preexisting L1 copies, which are significantly reshaped by natural selection. Our findings reveal that the L1 machinery has evolved to efficiently target all genomic regions and underline a predominant role for post-integrative processes on the distribution of endogenous L1 elements.
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Affiliation(s)
- Tania Sultana
- Université Côte d'Azur, Inserm, CNRS, IRCAN, Nice, France
| | | | - Oliver Siol
- Institut de Génétique Humaine, University of Montpellier, CNRS, Montpellier, France
| | | | | | - Amal Zine El Aabidine
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Léo Pioger
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Pilvi Nigumann
- Université Côte d'Azur, Inserm, CNRS, IRCAN, Nice, France
| | - Simona Saccani
- Université Côte d'Azur, Inserm, CNRS, IRCAN, Nice, France
| | - Jean-Christophe Andrau
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Nicolas Gilbert
- Institut de Génétique Humaine, University of Montpellier, CNRS, Montpellier, France; Institut de Médecine Régénératrice et de Biothérapie, Inserm U1183, CHU Montpellier, Montpellier, France
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218
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Lappalainen T, Scott AJ, Brandt M, Hall IM. Genomic Analysis in the Age of Human Genome Sequencing. Cell 2019; 177:70-84. [PMID: 30901550 PMCID: PMC6532068 DOI: 10.1016/j.cell.2019.02.032] [Citation(s) in RCA: 156] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 02/19/2019] [Accepted: 02/19/2019] [Indexed: 02/08/2023]
Abstract
Affordable genome sequencing technologies promise to revolutionize the field of human genetics by enabling comprehensive studies that interrogate all classes of genome variation, genome-wide, across the entire allele frequency spectrum. Ongoing projects worldwide are sequencing many thousands-and soon millions-of human genomes as part of various gene mapping studies, biobanking efforts, and clinical programs. However, while genome sequencing data production has become routine, genome analysis and interpretation remain challenging endeavors with many limitations and caveats. Here, we review the current state of technologies for genetic variant discovery, genotyping, and functional interpretation and discuss the prospects for future advances. We focus on germline variants discovered by whole-genome sequencing, genome-wide functional genomic approaches for predicting and measuring variant functional effects, and implications for studies of common and rare human disease.
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Affiliation(s)
- Tuuli Lappalainen
- New York Genome Center, New York, NY, USA; Department of Systems Biology, Columbia University, New York, NY, USA.
| | - Alexandra J Scott
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA; Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA; Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA
| | - Margot Brandt
- New York Genome Center, New York, NY, USA; Department of Systems Biology, Columbia University, New York, NY, USA
| | - Ira M Hall
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, MO, USA; Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA; Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA.
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219
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Dynamic Methylation of an L1 Transduction Family during Reprogramming and Neurodifferentiation. Mol Cell Biol 2019; 39:MCB.00499-18. [PMID: 30692270 PMCID: PMC6425141 DOI: 10.1128/mcb.00499-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/11/2019] [Indexed: 01/28/2023] Open
Abstract
The retrotransposon LINE-1 (L1) is a significant source of endogenous mutagenesis in humans. In each individual genome, a few retrotransposition-competent L1s (RC-L1s) can generate new heritable L1 insertions in the early embryo, primordial germ line, and germ cells. L1 retrotransposition can also occur in the neuronal lineage and cause somatic mosaicism. Although DNA methylation mediates L1 promoter repression, the temporal pattern of methylation applied to individual RC-L1s during neurogenesis is unclear. Here, we identified a de novo L1 insertion in a human induced pluripotent stem cell (hiPSC) line via retrotransposon capture sequencing (RC-seq). The L1 insertion was full-length and carried 5' and 3' transductions. The corresponding donor RC-L1 was part of a large and recently active L1 transduction family and was highly mobile in a cultured-cell L1 retrotransposition reporter assay. Notably, we observed distinct and dynamic DNA methylation profiles for the de novo L1 and members of its extended transduction family during neuronal differentiation. These experiments reveal how a de novo L1 insertion in a pluripotent stem cell is rapidly recognized and repressed, albeit incompletely, by the host genome during neurodifferentiation, while retaining potential for further retrotransposition.
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220
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Centromere Repeats: Hidden Gems of the Genome. Genes (Basel) 2019; 10:genes10030223. [PMID: 30884847 PMCID: PMC6471113 DOI: 10.3390/genes10030223] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/07/2019] [Accepted: 03/11/2019] [Indexed: 01/08/2023] Open
Abstract
Satellite DNAs are now regarded as powerful and active contributors to genomic and chromosomal evolution. Paired with mobile transposable elements, these repetitive sequences provide a dynamic mechanism through which novel karyotypic modifications and chromosomal rearrangements may occur. In this review, we discuss the regulatory activity of satellite DNA and their neighboring transposable elements in a chromosomal context with a particular emphasis on the integral role of both in centromere function. In addition, we discuss the varied mechanisms by which centromeric repeats have endured evolutionary processes, producing a novel, species-specific centromeric landscape despite sharing a ubiquitously conserved function. Finally, we highlight the role these repetitive elements play in the establishment and functionality of de novo centromeres and chromosomal breakpoints that underpin karyotypic variation. By emphasizing these unique activities of satellite DNAs and transposable elements, we hope to disparage the conventional exemplification of repetitive DNA in the historically-associated context of ‘junk’.
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221
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Schumann GG, Fuchs NV, Tristán-Ramos P, Sebe A, Ivics Z, Heras SR. The impact of transposable element activity on therapeutically relevant human stem cells. Mob DNA 2019; 10:9. [PMID: 30899334 PMCID: PMC6408843 DOI: 10.1186/s13100-019-0151-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 02/27/2019] [Indexed: 12/11/2022] Open
Abstract
Human stem cells harbor significant potential for basic and clinical translational research as well as regenerative medicine. Currently ~ 3000 adult and ~ 30 pluripotent stem cell-based, interventional clinical trials are ongoing worldwide, and numbers are increasing continuously. Although stem cells are promising cell sources to treat a wide range of human diseases, there are also concerns regarding potential risks associated with their clinical use, including genomic instability and tumorigenesis concerns. Thus, a deeper understanding of the factors and molecular mechanisms contributing to stem cell genome stability are a prerequisite to harnessing their therapeutic potential for degenerative diseases. Chemical and physical factors are known to influence the stability of stem cell genomes, together with random mutations and Copy Number Variants (CNVs) that accumulated in cultured human stem cells. Here we review the activity of endogenous transposable elements (TEs) in human multipotent and pluripotent stem cells, and the consequences of their mobility for genomic integrity and host gene expression. We describe transcriptional and post-transcriptional mechanisms antagonizing the spread of TEs in the human genome, and highlight those that are more prevalent in multipotent and pluripotent stem cells. Notably, TEs do not only represent a source of mutations/CNVs in genomes, but are also often harnessed as tools to engineer the stem cell genome; thus, we also describe and discuss the most widely applied transposon-based tools and highlight the most relevant areas of their biomedical applications in stem cells. Taken together, this review will contribute to the assessment of the risk that endogenous TE activity and the application of genetically engineered TEs constitute for the biosafety of stem cells to be used for substitutive and regenerative cell therapies.
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Affiliation(s)
- Gerald G Schumann
- 1Division of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Str.51-59, 63225 Langen, Germany
| | - Nina V Fuchs
- 2Host-Pathogen Interactions, Paul-Ehrlich-Institut, Paul-Ehrlich-Str. 51-59, 63225 Langen, Germany
| | - Pablo Tristán-Ramos
- 3GENYO. Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada-Avenida de la Ilustración, 114, 18016 Granada, Spain.,4Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, 18071 Granada, Spain
| | - Attila Sebe
- 1Division of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Str.51-59, 63225 Langen, Germany
| | - Zoltán Ivics
- 1Division of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Str.51-59, 63225 Langen, Germany
| | - Sara R Heras
- 3GENYO. Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada-Avenida de la Ilustración, 114, 18016 Granada, Spain.,4Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, 18071 Granada, Spain
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222
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Retroelement-Linked Transcription Factor Binding Patterns Point to Quickly Developing Molecular Pathways in Human Evolution. Cells 2019; 8:cells8020130. [PMID: 30736359 PMCID: PMC6406739 DOI: 10.3390/cells8020130] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 01/29/2019] [Accepted: 01/30/2019] [Indexed: 12/12/2022] Open
Abstract
Background: Retroelements (REs) are transposable elements occupying ~40% of the human genome that can regulate genes by providing transcription factor binding sites (TFBS). RE-linked TFBS profile can serve as a marker of gene transcriptional regulation evolution. This approach allows for interrogating the regulatory evolution of organisms with RE-rich genomes. We aimed to characterize the evolution of transcriptional regulation for human genes and molecular pathways using RE-linked TFBS accumulation as a metric. Methods: We characterized human genes and molecular pathways either enriched or deficient in RE-linked TFBS regulation. We used ENCODE database with mapped TFBS for 563 transcription factors in 13 human cell lines. For 24,389 genes and 3124 molecular pathways, we calculated the score of RE-linked TFBS regulation reflecting the regulatory evolution rate at the level of individual genes and molecular pathways. Results: The major groups enriched by RE regulation deal with gene regulation by microRNAs, olfaction, color vision, fertilization, cellular immune response, and amino acids and fatty acids metabolism and detoxication. The deficient groups were involved in translation, RNA transcription and processing, chromatin organization, and molecular signaling. Conclusion: We identified genes and molecular processes that have characteristics of especially high or low evolutionary rates at the level of RE-linked TFBS regulation in human lineage.
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Reznik B, Cincotta SA, Jaszczak RG, Mateo LJ, Shen J, Cao M, Baskin L, Ye P, An W, Laird DJ. Heterogeneity of transposon expression and activation of the repressive network in human fetal germ cells. Development 2019; 146:dev.171157. [PMID: 30658985 DOI: 10.1242/dev.171157] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 01/07/2019] [Indexed: 12/16/2022]
Abstract
Epigenetic resetting in germ cells during development de-represses transposable elements (TEs). piRNAs protect fetal germ cells by targeted mRNA destruction and deposition of repressive epigenetic marks. Here, we provide the first evidence for an active piRNA pathway and TE repression in germ cells of human fetal testis. We identify pre-pachytene piRNAs with features of secondary amplification that map most abundantly to the long interspersed element type 1 (L1) family of TEs. L1-ORF1p expression is heterogeneous in fetal germ cells, peaks at mid-gestation and declines concomitantly with increases in piRNAs, nuclear localization of HIWI2 and an increase in H3K9me3. Surprisingly, the same cells with accumulation of L1-ORF1p display highest levels of HIWI2 and H3K9me3. Conversely, the earliest germ cells with high levels of L1-ORF1p express low levels of the chaperone HSP90α. We propose that a subset of germ cells resists L1 expression, whereas L1-expressing germ cells activate the repression pathway that leads to epigenetic silencing of L1 via H3K9me3.
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Affiliation(s)
- Boris Reznik
- Department of Obstetrics, Gynecology and Reproductive Science; Center for Reproductive Sciences; Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Steven A Cincotta
- Department of Obstetrics, Gynecology and Reproductive Science; Center for Reproductive Sciences; Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Rebecca G Jaszczak
- Department of Obstetrics, Gynecology and Reproductive Science; Center for Reproductive Sciences; Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Leslie J Mateo
- Department of Obstetrics, Gynecology and Reproductive Science; Center for Reproductive Sciences; Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Joel Shen
- Department of Urology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Mei Cao
- Department of Urology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Laurence Baskin
- Department of Urology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Ping Ye
- Avera McKennan Hospital and University Health Center, Sioux Falls, SD 57105, USA.,Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007, USA
| | - Wenfeng An
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007, USA
| | - Diana J Laird
- Department of Obstetrics, Gynecology and Reproductive Science; Center for Reproductive Sciences; Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
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224
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Treger RS, Pope SD, Kong Y, Tokuyama M, Taura M, Iwasaki A. The Lupus Susceptibility Locus Sgp3 Encodes the Suppressor of Endogenous Retrovirus Expression SNERV. Immunity 2019; 50:334-347.e9. [PMID: 30709743 DOI: 10.1016/j.immuni.2018.12.022] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/18/2018] [Accepted: 12/17/2018] [Indexed: 12/24/2022]
Abstract
Elevated endogenous retrovirus (ERV) transcription and anti-ERV antibody reactivity are implicated in lupus pathogenesis. Overproduction of non-ecotropic ERV (NEERV) envelope glycoprotein gp70 and resultant nephritis occur in lupus-prone mice, but whether NEERV mis-expression contributes to lupus etiology is unclear. Here we identified suppressor of NEERV (Snerv) 1 and 2, Krüppel-associated box zinc-finger proteins (KRAB-ZFPs) that repressed NEERV by binding the NEERV long terminal repeat to recruit the transcriptional regulator KAP1. Germline Snerv1/Snerv2 deletion increased activating chromatin modifications, transcription, and gp70 expression from NEERV loci. F1 crosses of lupus-prone New Zealand Black (NZB) and 129 mice to Snerv1/Snerv2-/- mice failed to restore NEERV repression, demonstrating that loss of SNERV underlies the lupus autoantigen gp70 overproduction that promotes nephritis in susceptible mice and that SNERV encodes for Sgp3 (in NZB mice) and Gv-1 loci (in 129 mice). Increased ERV expression in lupus patients inversely correlated with three putative ERV-suppressing KRAB-ZFPs, suggesting that loss of KRAB-ZFP-mediated ERV control may contribute to human lupus pathogenesis.
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Affiliation(s)
- Rebecca S Treger
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Scott D Pope
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Yong Kong
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Molecular Biophysics and Biochemistry, W.M. Keck Foundation Biotechnology Resource Laboratory, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Maria Tokuyama
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Manabu Taura
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Akiko Iwasaki
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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225
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Abstract
Despite revolutionary advances in sequencing approaches, many mendelian disorders have remained unexplained. In this issue of Cell, Aneichyk et al. combine genomic and cell-type-specific transcriptomic data to causally link a non-coding mutation in the ubiquitous TAF1 gene to X-linked dystonia-parkinsonism.
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Affiliation(s)
- Enza Maria Valente
- Department of Molecular Medicine, University of Pavia, Pavia, Italy; Neurogenetics Unit, IRCCS Santa Lucia Foundation, Rome, Italy.
| | - Kailash P Bhatia
- Sobell Department, Institute of Neurology, University College of London, London, UK
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226
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Nishioka M, Bundo M, Iwamoto K, Kato T. Somatic mutations in the human brain: implications for psychiatric research. Mol Psychiatry 2019; 24:839-856. [PMID: 30087451 PMCID: PMC6756205 DOI: 10.1038/s41380-018-0129-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 03/27/2018] [Accepted: 05/25/2018] [Indexed: 01/18/2023]
Abstract
Psychiatric disorders such as schizophrenia and bipolar disorder are caused by complex gene-environment interactions. While recent advances in genomic technologies have enabled the identification of several risk variants for psychiatric conditions, including single-nucleotide variants and copy-number variations, these factors can explain only a portion of the liability to these disorders. Although non-inherited factors had previously been attributed to environmental causes, recent genomic analyses have demonstrated that de novo mutations are among the main non-inherited risk factors for several psychiatric conditions. Somatic mutations in the brain may also explain how stochastic developmental events and environmental insults confer risk for a psychiatric disorder following fertilization. Here, we review evidence regarding somatic mutations in the brains of individuals with and without neuropsychiatric diseases. We further discuss the potential biological mechanisms underlying somatic mutations in the brain as well as the technical issues associated with the detection of somatic mutations in psychiatric research.
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Affiliation(s)
- Masaki Nishioka
- 0000 0001 2151 536Xgrid.26999.3dDivision for Counseling and Support, The University of Tokyo, Tokyo, Japan
| | - Miki Bundo
- 0000 0001 0660 6749grid.274841.cDepartment of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan ,0000 0004 1754 9200grid.419082.6PRESTO, Japan Science and Technology Agency, Saitama, Japan
| | - Kazuya Iwamoto
- Department of Molecular Brain Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
| | - Tadafumi Kato
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Saitama, Japan.
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227
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Bodak M, Yu J, Ciaudo C. Regulation of LINE-1 Elements by miR-128 Is Not Conserved in Mouse Embryonic Stem Cells. Front Genet 2018; 9:683. [PMID: 30619491 PMCID: PMC6306448 DOI: 10.3389/fgene.2018.00683] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 12/07/2018] [Indexed: 12/22/2022] Open
Affiliation(s)
- Maxime Bodak
- Department of Biology, Swiss Federal Institute of Technology Zurich, IMHS, Zurich, Switzerland
| | - Jian Yu
- Department of Biology, Swiss Federal Institute of Technology Zurich, IMHS, Zurich, Switzerland
| | - Constance Ciaudo
- Department of Biology, Swiss Federal Institute of Technology Zurich, IMHS, Zurich, Switzerland
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228
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Pereira GC, Sanchez L, Schaughency PM, Rubio-Roldán A, Choi JA, Planet E, Batra R, Turelli P, Trono D, Ostrow LW, Ravits J, Kazazian HH, Wheelan SJ, Heras SR, Mayer J, García-Pérez JL, Goodier JL. Properties of LINE-1 proteins and repeat element expression in the context of amyotrophic lateral sclerosis. Mob DNA 2018; 9:35. [PMID: 30564290 PMCID: PMC6295051 DOI: 10.1186/s13100-018-0138-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 11/15/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease involving loss of motor neurons and having no known cure and uncertain etiology. Several studies have drawn connections between altered retrotransposon expression and ALS. Certain features of the LINE-1 (L1) retrotransposon-encoded ORF1 protein (ORF1p) are analogous to those of neurodegeneration-associated RNA-binding proteins, including formation of cytoplasmic aggregates. In this study we explore these features and consider possible links between L1 expression and ALS. RESULTS We first considered factors that modulate aggregation and subcellular distribution of LINE-1 ORF1p, including nuclear localization. Changes to some ORF1p amino acid residues alter both retrotransposition efficiency and protein aggregation dynamics, and we found that one such polymorphism is present in endogenous L1s abundant in the human genome. We failed, however, to identify CRM1-mediated nuclear export signals in ORF1p nor strict involvement of cell cycle in endogenous ORF1p nuclear localization in human 2102Ep germline teratocarcinoma cells. Some proteins linked with ALS bind and colocalize with L1 ORF1p ribonucleoprotein particles in cytoplasmic RNA granules. Increased expression of several ALS-associated proteins, including TAR DNA Binding Protein (TDP-43), strongly limits cell culture retrotransposition, while some disease-related mutations modify these effects. Using quantitative reverse transcription PCR (RT-qPCR) of ALS tissues and reanalysis of publicly available RNA-Seq datasets, we asked if changes in expression of retrotransposons are associated with ALS. We found minimal altered expression in sporadic ALS tissues but confirmed a previous report of differential expression of many repeat subfamilies in C9orf72 gene-mutated ALS patients. CONCLUSIONS Here we extended understanding of the subcellular localization dynamics of the aggregation-prone LINE-1 ORF1p RNA-binding protein. However, we failed to find compelling evidence for misregulation of LINE-1 retrotransposons in sporadic ALS nor a clear effect of ALS-associated TDP-43 protein on L1 expression. In sum, our study reveals that the interplay of active retrotransposons and the molecular features of ALS are more complex than anticipated. Thus, the potential consequences of altered retrotransposon activity for ALS and other neurodegenerative disorders are worthy of continued investigation.
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Affiliation(s)
- Gavin C. Pereira
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland USA
| | - Laura Sanchez
- GENYO. Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
| | - Paul M. Schaughency
- Oncology Center-Cancer Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland USA
| | - Alejandro Rubio-Roldán
- GENYO. Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
| | - Jungbin A. Choi
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland USA
| | - Evarist Planet
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Ranjan Batra
- Department of Neurosciences, School of Medicine, University of California at San Diego, San Diego, California USA
| | - Priscilla Turelli
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Didier Trono
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Lyle W. Ostrow
- Neuromuscular Division, Johns Hopkins University School of Medicine, Baltimore, Maryland USA
| | - John Ravits
- Department of Neurosciences, School of Medicine, University of California at San Diego, San Diego, California USA
| | - Haig H. Kazazian
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland USA
| | - Sarah J. Wheelan
- Oncology Center-Cancer Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland USA
| | - Sara R. Heras
- GENYO. Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
- Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Granada, Spain
| | - Jens Mayer
- Department of Human Genetics, Medical Faculty, University of Saarland, Homburg/Saar, Germany
| | - Jose Luis García-Pérez
- GENYO. Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine (IGMM), University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - John L. Goodier
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland USA
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229
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Tavares E, Tang CY, Vig A, Li S, Billingsley G, Sung W, Vincent A, Thiruvahindrapuram B, Héon E. Retrotransposon insertion as a novel mutational event in Bardet-Biedl syndrome. Mol Genet Genomic Med 2018; 7:e00521. [PMID: 30484961 PMCID: PMC6393654 DOI: 10.1002/mgg3.521] [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: 07/19/2018] [Revised: 08/23/2018] [Accepted: 10/26/2018] [Indexed: 01/12/2023] Open
Abstract
Background Bardet‐Biedl syndrome (BBS) is an autosomal recessive pleiotropic disorder of the primary cilia that leads to severe visual loss in the teenage years. Approximately 80% of BBS cases are explained by mutations in one of the 21 identified genes. Documented causative mutation types include missense, nonsense, copy number variation (CNV), frameshift deletions or insertions, and splicing variants. Methods Whole genome sequencing was performed on a patient affected with BBS for whom no mutations were identified using clinically approved genetic testing of the known genes. Analysis of the WGS was done using internal protocols and publicly available algorithms. The phenotype was defined by retrospective chart review. Results We document a female affected with BBS carrying the most common BBS1 mutation (BBS1: Met390Arg) on the maternal allele and an insertion of a ~1.7‐kb retrotransposon in exon 13 on the paternal allele. This retrotransposon insertion was not automatically annotated by the standard variant calling protocols used. This novel variant was identified by visual inspection of the alignment file followed by specific genome analysis with an available algorithm for transposable elements. Conclusion This report documents a novel mutation type associated with BBS and highlights the importance of systematically performing transposon detection analysis on WGS data of unsolved cases.
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Affiliation(s)
- Erika Tavares
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Chen Yu Tang
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Anjali Vig
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Shuning Li
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Gail Billingsley
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Wilson Sung
- The Centre for Applied Genomics, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ajoy Vincent
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Ophthalmology and Vision Sciences, Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - Elise Héon
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Ophthalmology and Vision Sciences, Hospital for Sick Children, Toronto, Ontario, Canada
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230
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Genomic mosaicism in the pathogenesis and inheritance of a Rett syndrome cohort. Genet Med 2018; 21:1330-1338. [PMID: 30405208 PMCID: PMC6752670 DOI: 10.1038/s41436-018-0348-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 10/17/2018] [Indexed: 01/01/2023] Open
Abstract
PURPOSE To determine the role of mosaicism in the pathogenesis and inheritance of Rett and Rett-like disorders. METHODS We recruited 471 Rett and Rett-like patients. Panel-sequencing targeting MECP2, CDKL5, and FOXG1 was performed. Mosaicism was quantified in 147 patients by a Bayesian genotyper. Candidates were validated by amplicon sequencing and digital PCR. Germline mosaicism of 21 fathers with daughters carrying pathogenic MECP2 variants was further quantified. RESULTS Pathogenic variants of MECP2/CDKL5/FOXG1 were found in 324/471 (68.7%) patients. Somatic MECP2 mosaicism was confirmed in 5/471 (1.1%) patients, including 3/18 males (16.7%) and 2/453 females (0.4%). Three of the five patients with somatic MECP2 mosaicism had mosaicism at MECP2-Arg106. Germline MECP2 mosaicism was detected in 5/21 (23.8%) fathers. CONCLUSION This is the first systematic screening of somatic and paternal germline MECP2 mosaicism at a cohort level. Our findings indicate that somatic MECP2 mosaicism contributes directly to the pathogenicity of Rett syndrome, especially in male patients. MECP2-Arg106 might be a mosaic hotspot. The high proportion of paternal germline MECP2 mosaicism indicates an underestimated mechanism underlying the paternal origin bias of MECP2 variants. Finally, this study provides an empirical foundation for future studies of genetic disorders caused by de novo variations of strong paternal origin.
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231
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Roos D, de Boer M. Retrotransposable genetic elements causing neutrophil defects. Eur J Clin Invest 2018; 48 Suppl 2:e12953. [PMID: 29774526 DOI: 10.1111/eci.12953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 05/12/2018] [Indexed: 01/28/2023]
Abstract
BACKGROUND Retrotransposable elements are stretches of DNA that encode proteins with the inherent ability to insert their own RNA or another RNA by reverse transcriptase as DNA into a new genomic location. In humans, the only autonomous retrotransposable elements are members of the Long INterspersed Element-1 (LINE-1) family. LINE-1s may cause gene inactivation and human disease. DESIGN We present a brief summary of the published knowledge about LINE-1s in humans and the RNAs that these elements can transpose, and we focus on the effect of LINE-1-mediated retrotransposition on human neutrophil function. RESULTS Retrotransposons can cause genetic disease by two primary mechanisms: (1) insertional mutagenesis and (2) nonallelic homologous recombination. The only known neutrophil function affected by retrotransposition is that of NADPH oxidase activity. Four patients with chronic granulomatous disease (CGD) are known with LINE-1-mediated insertional inactivation of CYBB, the gene that encodes the gp91phox component of the phagocyte NADPH oxidase. In addition, 5 CGD patients had a large deletion in the NCF2 gene, encoding the p67phox component, and 2 CGD patients had a similar deletion in NCF1, encoding p47phox . These deletions were caused by nonallelic homologous recombination between 2 Alu elements at the borders of each deletion. Alu elements have spread throughout the human genome by LINE-1 retrotransposition. CONCLUSIONS Probably, the occurrence of LINE-1-mediated insertions causing autosomal CGD has been underestimated. It might be worthwhile to reinvestigate the DNA from autosomal CGD patients with missplice mutations and large deletions for indications of LINE-1-mediated insertions.
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Affiliation(s)
- Dirk Roos
- Sanquin Research, and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Martin de Boer
- Sanquin Research, and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
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232
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De novo unbalanced translocations have a complex history/aetiology. Hum Genet 2018; 137:817-829. [DOI: 10.1007/s00439-018-1941-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 09/24/2018] [Indexed: 12/21/2022]
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233
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Curtin F, Bernard C, Levet S, Perron H, Porchet H, Médina J, Malpass S, Lloyd D, Simpson R. A new therapeutic approach for type 1 diabetes: Rationale for GNbAC1, an anti-HERV-W-Env monoclonal antibody. Diabetes Obes Metab 2018; 20:2075-2084. [PMID: 29749030 DOI: 10.1111/dom.13357] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 12/22/2022]
Abstract
We describe a newly identified therapeutic target for type 1 diabetes (T1D): an envelope protein of endogenous retroviral origin, human endogenous retrovirus W envelope (HERV-W-Env). HERV-W-Env was found to be detected in the blood of ~60% of patients with T1D and is expressed in acinar pancreatic cells of 75% of patients with T1D at post mortem examination. Preclinical experiments showed that this protein displays direct cytotoxicity on human β-islet cells. In vivo HERV-W-Env impairs the insulin and glucose metabolism in transgenic mice expressing HERV-W-Env. GNbAC1, an IgG4 monoclonal antibody, has been developed to specifically target HERV-W-Env and to neutralize the effect of HERV-W-Env in vitro and in vivo. GNbAC1 is currently in clinical development for multiple sclerosis and > 300 subjects have been administered with GNbAC1 so far. GNbAC1 is now being tested in T1D in the RAINBOW-T1D study, which is a randomized placebo-controlled study with the objective of showing the safety and pharmacodynamic response of GNbAC1 in patients who have had T1D with a maximum of 4 years' duration. GNbAC1 is being tested vs placebo at the dose of 6 mg/kg in 60 patients during six repeated administrations for 6 months; a 6-month open-label extension will follow. The primary endpoint is to assess safety, and secondary endpoints are the pharmacodynamic responses to GNbAC1. GNbAC1 targeting HERV-W-Env is currently in clinical development in T1D, with the first safety and pharmacodynamic study. If the study results are positive, this may open the door to the development of an innovative non-immunomodulatory disease-modifying treatment for T1D.
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Affiliation(s)
- Francois Curtin
- GeNeuro SA, Plan-les-Ouates, Switzerland
- Division of Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | | | | | - Hervé Perron
- GeNeuro SA, Plan-les-Ouates, Switzerland
- Geneuro-Innovation, Lyon, France
- Laboratory of Immune Deficiencies, Faculty of Medicine Laënnec, University of Lyon, Lyon, France
| | - Hervé Porchet
- GeNeuro SA, Plan-les-Ouates, Switzerland
- Department of Pharmacology, University of Pretoria, Pretoria, South Africa
| | | | - Sam Malpass
- Southern Star Research Pty Ltd, Gordon, Australia
| | - David Lloyd
- Southern Star Research Pty Ltd, Gordon, Australia
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234
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Nzabarushimana E, Tang H. Insertion sequence elements-mediated structural variations in bacterial genomes. Mob DNA 2018; 9:29. [PMID: 30181787 PMCID: PMC6114881 DOI: 10.1186/s13100-018-0134-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 08/16/2018] [Indexed: 12/20/2022] Open
Abstract
Mobile genetic elements (MGEs) impact the evolution and stability of their host genomes. Insertion sequence (IS) elements are the most common MGEs in bacterial genomes and play a crucial role in mediating large-scale variations in bacterial genomes. It is understood that IS elements and MGEs in general coexist in a dynamical equilibrium with their respective hosts. Current studies indicate that the spontaneous movement of IS elements does not follow a constant rate in different bacterial genomes. However, due to the paucity and sparsity of the data, these observations are yet to be conclusive. In this paper, we conducted a comparative analysis of the IS-mediated genome structural variations in ten mutation accumulation (MA) experiments across eight strains of five bacterial species containing IS elements, including four strains of the E. coli. We used GRASPER algorithm, a denovo structural variation (SV) identification algorithm designed to detect SVs involving repetitive sequences in the genome. We observed highly diverse rates of IS insertions and IS-mediated recombinations across different bacterial species as well as across different strains of the same bacterial species. We also observed different rates of the elements from the same IS family in different bacterial genomes, suggesting that the distinction in rates might not be due to the different composition of IS elements across bacterial genomes.
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Affiliation(s)
- Etienne Nzabarushimana
- School of Informatics, Computing and Engineering, Indiana University, Bloomington, IN USA
| | - Haixu Tang
- School of Informatics, Computing and Engineering, Indiana University, Bloomington, IN USA
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235
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Szafranski P, Kośmider E, Liu Q, Karolak JA, Currie L, Parkash S, Kahler SG, Roeder E, Littlejohn RO, DeNapoli TS, Shardonofsky FR, Henderson C, Powers G, Poisson V, Bérubé D, Oligny L, Michaud JL, Janssens S, De Coen K, Van Dorpe J, Dheedene A, Harting MT, Weaver MD, Khan AM, Tatevian N, Wambach J, Gibbs KA, Popek E, Gambin A, Stankiewicz P. LINE- and Alu-containing genomic instability hotspot at 16q24.1 associated with recurrent and nonrecurrent CNV deletions causative for ACDMPV. Hum Mutat 2018; 39:1916-1925. [PMID: 30084155 DOI: 10.1002/humu.23608] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 08/01/2018] [Accepted: 08/02/2018] [Indexed: 01/20/2023]
Abstract
Transposable elements modify human genome by inserting into new loci or by mediating homology-, microhomology-, or homeology-driven DNA recombination or repair, resulting in genomic structural variation. Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) is a rare lethal neonatal developmental lung disorder caused by point mutations or copy-number variant (CNV) deletions of FOXF1 or its distant tissue-specific enhancer. Eighty-five percent of 45 ACDMPV-causative CNV deletions, of which junctions have been sequenced, had at least one of their two breakpoints located in a retrotransposon, with more than half of them being Alu elements. We describe a novel ∼35 kb-large genomic instability hotspot at 16q24.1, involving two evolutionarily young LINE-1 (L1) elements, L1PA2 and L1PA3, flanking AluY, two AluSx, AluSx1, and AluJr elements. The occurrence of L1s at this location coincided with the branching out of the Homo-Pan-Gorilla clade, and was preceded by the insertion of AluSx, AluSx1, and AluJr. Our data show that, in addition to mediating recurrent CNVs, L1 and Alu retrotransposons can predispose the human genome to formation of variably sized CNVs, both of clinical and evolutionary relevance. Nonetheless, epigenetic or other genomic features of this locus might also contribute to its increased instability.
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Affiliation(s)
- Przemyslaw Szafranski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Ewelina Kośmider
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Warsaw, Poland
| | - Qian Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Justyna A Karolak
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Poznan, Poland
| | - Lauren Currie
- Maritime Medical Genetics Service, IWK Health Centre, Halifax, Canada
| | - Sandhya Parkash
- Maritime Medical Genetics Service, IWK Health Centre, Halifax, Canada
| | - Stephen G Kahler
- Section of Genetics and Metabolism, Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Elizabeth Roeder
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Department of Pediatrics, Baylor College of Medicine, San Antonio, Texas
| | | | - Thomas S DeNapoli
- Department of Pathology, Children's Hospital of San Antonio, San Antonio, Texas
| | - Felix R Shardonofsky
- Pediatric Pulmonary Center, Children's Hospital of San Antonio, San Antonio, Texas
| | - Cody Henderson
- Department of Pediatrics, Baylor College of Medicine, San Antonio, Texas.,Neonatal-Perinatal Medicine, Children's Hospital of San Antonio, San Antonio, Texas
| | - George Powers
- Department of Pediatrics, Baylor College of Medicine, San Antonio, Texas.,Neonatal-Perinatal Medicine, Children's Hospital of San Antonio, San Antonio, Texas
| | | | | | | | | | - Sandra Janssens
- Center for Medical Genetics, Ghent University, Ghent, Belgium
| | - Kris De Coen
- Department of Neonatal Intensive Care, Ghent University, Ghent, Belgium
| | - Jo Van Dorpe
- Department of Pathology, Ghent University, Ghent, Belgium
| | | | | | | | - Amir M Khan
- McGovern Medical School at UTHealth, Houston, Texas
| | | | - Jennifer Wambach
- Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri
| | - Kathleen A Gibbs
- Children's Hospital of Philadelphia, and University of Pennsylvania, Philadelphia, Pennsylvania
| | - Edwina Popek
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas
| | - Anna Gambin
- Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Warsaw, Poland
| | - Paweł Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
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236
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Monlong J, Cossette P, Meloche C, Rouleau G, Girard SL, Bourque G. Human copy number variants are enriched in regions of low mappability. Nucleic Acids Res 2018; 46:7236-7249. [PMID: 30137632 PMCID: PMC6101599 DOI: 10.1093/nar/gky538] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/04/2018] [Accepted: 06/12/2018] [Indexed: 12/18/2022] Open
Abstract
Copy number variants (CNVs) are known to affect a large portion of the human genome and have been implicated in many diseases. Although whole-genome sequencing (WGS) can help identify CNVs, most analytical methods suffer from limited sensitivity and specificity, especially in regions of low mappability. To address this, we use PopSV, a CNV caller that relies on multiple samples to control for technical variation. We demonstrate that our calls are stable across different types of repeat-rich regions and validate the accuracy of our predictions using orthogonal approaches. Applying PopSV to 640 human genomes, we find that low-mappability regions are approximately 5 times more likely to harbor germline CNVs, in stark contrast to the nearly uniform distribution observed for somatic CNVs in 95 cancer genomes. In addition to known enrichments in segmental duplication and near centromeres and telomeres, we also report that CNVs are enriched in specific types of satellite and in some of the most recent families of transposable elements. Finally, using this comprehensive approach, we identify 3455 regions with recurrent CNVs that were missing from existing catalogs. In particular, we identify 347 genes with a novel exonic CNV in low-mappability regions, including 29 genes previously associated with disease.
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Affiliation(s)
- Jean Monlong
- Department of Human Genetics, McGill University, Montréal H3A 1B1, Canada
- Canadian Center for Computational Genomics, Montréal H3A 1A4, Canada
| | - Patrick Cossette
- Centre de Recherche du Centre Hospitalier de l’Universite de Montréal, Montréal H2X 0A9, Canada
| | - Caroline Meloche
- Centre de Recherche du Centre Hospitalier de l’Universite de Montréal, Montréal H2X 0A9, Canada
| | - Guy Rouleau
- Montreal Neurological Institute, McGill University, Montréal H3A 2B4, Canada
| | - Simon L Girard
- Department of Human Genetics, McGill University, Montréal H3A 1B1, Canada
- Centre de Recherche du Centre Hospitalier de l’Universite de Montréal, Montréal H2X 0A9, Canada
- Département des sciences fondamentales, Université du Québec à Chicoutimi, Chicoutimi G7H 2B1, Canada
| | - Guillaume Bourque
- Department of Human Genetics, McGill University, Montréal H3A 1B1, Canada
- Canadian Center for Computational Genomics, Montréal H3A 1A4, Canada
- McGill University and Génome Québec Innovation Center, Montréal H3A 1A4, Canada
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237
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Wang L, Dou K, Moon S, Tan FJ, Zhang ZZ. Hijacking Oogenesis Enables Massive Propagation of LINE and Retroviral Transposons. Cell 2018; 174:1082-1094.e12. [PMID: 30057117 DOI: 10.1016/j.cell.2018.06.040] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 05/08/2018] [Accepted: 06/20/2018] [Indexed: 10/28/2022]
Abstract
Although animals have evolved multiple mechanisms to suppress transposons, "leaky" mobilizations that cause mutations and diseases still occur. This suggests that transposons employ specific tactics to accomplish robust propagation. By directly tracking mobilization, we show that, during a short and specific time window of oogenesis, retrotransposons achieve massive amplification via a cell-type-specific targeting strategy. Retrotransposons rarely mobilize in undifferentiated germline stem cells. However, as oogenesis proceeds, they utilize supporting nurse cells-which are highly polyploid and eventually undergo apoptosis-as factories to massively manufacture invading products. Moreover, retrotransposons rarely integrate into nurse cells themselves but, instead, via microtubule-mediated transport, they preferentially target the DNA of the interconnected oocytes. Blocking microtubule-dependent intercellular transport from nurse cells significantly alleviates damage to the oocyte genome. Our data reveal that parasitic genomic elements can efficiently hijack a host developmental process to propagate robustly, thereby driving evolutionary change and causing disease.
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Affiliation(s)
- Lu Wang
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218, USA
| | - Kun Dou
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218, USA
| | - Sungjin Moon
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218, USA
| | - Frederick J Tan
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218, USA
| | - Zz Zhao Zhang
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218, USA.
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238
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Faulkner GJ, Billon V. L1 retrotransposition in the soma: a field jumping ahead. Mob DNA 2018; 9:22. [PMID: 30002735 PMCID: PMC6035798 DOI: 10.1186/s13100-018-0128-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 06/27/2018] [Indexed: 12/13/2022] Open
Abstract
Retrotransposons are transposable elements (TEs) capable of "jumping" in germ, embryonic and tumor cells and, as is now clearly established, in the neuronal lineage. Mosaic TE insertions form part of a broader landscape of somatic genome variation and hold significant potential to generate phenotypic diversity, in the brain and elsewhere. At present, the LINE-1 (L1) retrotransposon family appears to be the most active autonomous TE in most mammals, based on experimental data obtained from disease-causing L1 mutations, engineered L1 reporter systems tested in cultured cells and transgenic rodents, and single-cell genomic analyses. However, the biological consequences of almost all somatic L1 insertions identified thus far remain unknown. In this review, we briefly summarize the current state-of-the-art in the field, including estimates of L1 retrotransposition rate in neurons. We bring forward the hypothesis that an extensive subset of retrotransposition-competent L1s may be de-repressed and mobile in the soma but largely inactive in the germline. We discuss recent reports of non-canonical L1-associated sequence variants in the brain and propose that the elevated L1 DNA content reported in several neurological disorders may predominantly comprise accumulated, unintegrated L1 nucleic acids, rather than somatic L1 insertions. Finally, we consider the main objectives and obstacles going forward in elucidating the biological impact of somatic retrotransposition.
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Affiliation(s)
- Geoffrey J. Faulkner
- Mater Research Institute – University of Queensland, TRI Building, Woolloongabba, QLD 4102 Australia
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD 4072 Australia
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072 Australia
| | - Victor Billon
- Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072 Australia
- Biology Department, École Normale Supérieure Paris-Saclay, 61 Avenue du Président Wilson, 94230 Cachan, France
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239
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Richardson SR, Faulkner GJ. Heritable L1 Retrotransposition Events During Development: Understanding Their Origins: Examination of heritable, endogenous L1 retrotransposition in mice opens up exciting new questions and research directions. Bioessays 2018; 40:e1700189. [PMID: 29709066 PMCID: PMC6681178 DOI: 10.1002/bies.201700189] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 03/04/2018] [Indexed: 01/08/2023]
Abstract
The retrotransposon Long Interspersed Element 1 (LINE-1 or L1) has played a major role in shaping the sequence composition of the mammalian genome. In our recent publication, "Heritable L1 retrotransposition in the mouse primordial germline and early embryo," we systematically assessed the rate and developmental timing of de novo, heritable endogenous L1 insertions in mice. Such heritable retrotransposition events allow L1 to exert an ongoing influence upon genome evolution. Here, we place our findings in the context of earlier studies, and highlight how our results corroborate, and depart from, previous research based on human patient samples and transgenic mouse models harboring engineered L1 reporter genes. In parallel, we outline outstanding questions regarding the stage-specificity, regulation, and functional impact of embryonic and germline L1 retrotransposition, and propose avenues for future research in this field.
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Affiliation(s)
- Sandra R. Richardson
- Mater Research Institute–University of QueenslandWoolloongabbaQueensland 4102Australia
| | - Geoffrey J. Faulkner
- Mater Research Institute–University of QueenslandWoolloongabbaQueensland 4102Australia
- Queensland Brain InstituteUniversity of QueenslandBrisbaneQueensland 4072Australia
- School of Biomedical SciencesUniversity of QueenslandBrisbaneQueensland 4072Australia
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240
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Krestel H, Meier JC. RNA Editing and Retrotransposons in Neurology. Front Mol Neurosci 2018; 11:163. [PMID: 29875629 PMCID: PMC5974252 DOI: 10.3389/fnmol.2018.00163] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/30/2018] [Indexed: 12/28/2022] Open
Abstract
Compared to sites in protein-coding sequences many more targets undergoing adenosine to inosine (A-to-I) RNA editing were discovered in non-coding regions of human cerebral transcripts, particularly in genetic transposable elements called retrotransposons. We review here the interaction mechanisms of RNA editing and retrotransposons and their impact on normal function and human neurological diseases. Exemplarily, A-to-I editing of retrotransposons embedded in protein-coding mRNAs can contribute to protein abundance and function via circular RNA formation, alternative splicing, and exonization or silencing of retrotransposons. Interactions leading to disease are not very well understood. We describe human diseases with involvement of the central nervous system including inborn errors of metabolism, neurodevelopmental disorders, neuroinflammatory and neurodegenerative and paroxysmal diseases, in which retrotransposons (Alu and/or L1 elements) appear to be causally involved in genetic rearrangements. Sole binding of single-stranded retrotransposon transcripts by RNA editing enzymes rather than enzymatic deamination may have a homeostatic effect on retrotransposon turnover. We also review evidence in support of the emerging pathophysiological function of A-to-I editing of retrotransposons in inflammation and its implication for different neurological diseases including amyotrophic lateral sclerosis, frontotemporal dementia, Alzheimer's and Parkinson's disease, and epilepsy.
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Affiliation(s)
- Heinz Krestel
- Department of Neurology, Bern University Hospital and University of Bern, Bern, Switzerland.,Department for BioMedical Research, Bern University Hospital and University of Bern, Bern, Switzerland
| | - Jochen C Meier
- Division Cell Physiology, Zoological Institute, Technical University Braunschweig, Braunschweig, Germany
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241
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Bartlett AA, Hunter RG. Transposons, stress and the functions of the deep genome. Front Neuroendocrinol 2018; 49:170-174. [PMID: 29551355 DOI: 10.1016/j.yfrne.2018.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 03/05/2018] [Accepted: 03/14/2018] [Indexed: 12/31/2022]
Abstract
The brain is responsible for both recognition and adaptation to stressful stimuli. Many molecular mechanisms have been implicated in this response including those governing neuronal plasticity, neurogenesis and, changes gene expression. Far less is known regarding effects of stress on the deep genome. In the hippocampus, stress appears to regulate expression of non-coding elements of the genome as well as the chromatin permissive for their transcription. Specifically, hippocampal retrotransposon (RT) elements are regulated by acute stress via the accumulation of the repressive H3K9me3 mark at RT loci. Further, corticosteroids appear to induce changes in heterochromatin status as well as RT expression in both adrenalectomized animal and rat cell culture models. Dysregulation of RT expression is predicted to result in functional deficits in affected brain areas. More broadly, however, transposons may have a variety of adaptive functions. As techniques improve to probe the deep genome, this approach to understanding stress neurobiology has the potential to yield insights into environment and genome interactions that may contribute to the physiology underlying a number of stress-related mental health disorders.
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Affiliation(s)
- Andrew A Bartlett
- University of Massachusetts Boston, Department of Psychology, University of Massachusetts, Boston, MA, USA
| | - Richard G Hunter
- University of Massachusetts Boston, Department of Psychology, University of Massachusetts, Boston, MA, USA; Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA.
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242
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Naufer MN, Furano AV, Williams MC. Protein-nucleic acid interactions of LINE-1 ORF1p. Semin Cell Dev Biol 2018; 86:140-149. [PMID: 29596909 PMCID: PMC6428221 DOI: 10.1016/j.semcdb.2018.03.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 03/19/2018] [Accepted: 03/23/2018] [Indexed: 11/03/2022]
Abstract
Long interspersed nuclear element 1 (LINE-1 or L1) is the dominant retrotransposon in mammalian genomes. L1 encodes two proteins ORF1p and ORF2p that are required for retrotransposition. ORF2p functions as the replicase. ORF1p is a coiled coil-mediated trimeric, high affinity RNA binding protein that packages its full- length coding transcript into an ORF2p-containing ribonucleoprotein (RNP) complex, the retrotransposition intermediate. ORF1p also is a nucleic acid chaperone that presumably facilitates the proposed nucleic acid remodeling steps involved in retrotransposition. Although detailed mechanistic understanding of ORF1p function in this process is lacking, recent studies showed that the rate at which ORF1p can form stable nucleic acid-bound oligomers in vitro is positively correlated with formation of an active L1 RNP as assayed in vivo using a cell culture-based retrotransposition assay. This rate was sensitive to minor amino acid changes in the coiled coil domain, which had no effect on nucleic acid chaperone activity. Additional studies linking the complex nucleic acid binding properties to the conformational changes of the protein are needed to understand how ORF1p facilitates retrotransposition.
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Affiliation(s)
- M Nabuan Naufer
- Northeastern University, Department of Physics, Boston, MA 02115, USA
| | - Anthony V Furano
- The Laboratory of Molecular and Cellular Biology, NIDDK, NIH, Bethesda, MD 20892, USA
| | - Mark C Williams
- Northeastern University, Department of Physics, Boston, MA 02115, USA.
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243
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Herrmann A, Wittmann S, Thomas D, Shepard CN, Kim B, Ferreirós N, Gramberg T. The SAMHD1-mediated block of LINE-1 retroelements is regulated by phosphorylation. Mob DNA 2018; 9:11. [PMID: 29610582 PMCID: PMC5872582 DOI: 10.1186/s13100-018-0116-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 03/19/2018] [Indexed: 12/22/2022] Open
Abstract
Background The restriction factor SAMHD1 regulates intracellular nucleotide level by degrading dNTPs and blocks the replication of retroviruses and DNA viruses in non-cycling cells, like macrophages or dendritic cells. In patients, inactivating mutations in samhd1 are associated with the autoimmune disease Aicardi-Goutières Syndrome (AGS). The accumulation of intracellular nucleic acids derived from endogenous retroelements thriving in the absence of SAMHD1 has been discussed as potential trigger of the autoimmune reaction. In vitro, SAMHD1 has been found to restrict endogenous retroelements, like LINE-1 elements (L1). The mechanism, however, by which SAMHD1 blocks endogenous retroelements, is still unclear. Results Here, we show that SAMHD1 inhibits the replication of L1 and other endogenous retroelements in cycling cells. By applying GFP- and neomycin-based reporter assays we found that the anti-L1 activity of SAMHD1 is regulated by phosphorylation at threonine 592 (T592). Similar to the block of HIV, the cofactor binding site and the enzymatic active HD domain of SAMHD1 proofed to be essential for restriction of L1 elements. However, phosphorylation at T592 did not correlate with the dNTP hydrolase activity of SAMHD1 in cycling 293T cells suggesting an alternative mechanism of regulation. Interestingly, we found that SAMHD1 binds to ORF2 protein of L1 and that this interaction is regulated by T592 phosphorylation. Together with the finding that the block is also active in cycling cells, our results suggest that the SAMHD1-mediated inhibition of L1 is similar but not identical to HIV restriction. Conclusion Our findings show conclusively that SAMHD1 restricts the replication of endogenous retroelements in vitro. The results suggest that SAMHD1 is important for maintaining genome integrity and support the idea of an enhanced replication of endogenous retroelements in the absence of SAMHD1 in vivo, potentially triggering autoimmune diseases like AGS. Our analysis also contributes to the better understanding of the activities of SAMHD1 in antiviral defense and nucleotide metabolism. The finding that the phosphorylation of SAMHD1 at T592 regulates its activity against retroelements but not necessarily intracellular dNTP level suggests that the dNTP hydrolase activity might not be the only function of SAMHD1 important for its antiviral activity and for controlling autoimmunity. Electronic supplementary material The online version of this article (10.1186/s13100-018-0116-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alexandra Herrmann
- 1Institute of Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, Schlossgarten 4, 91054 Erlangen, Germany
| | - Sabine Wittmann
- 1Institute of Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, Schlossgarten 4, 91054 Erlangen, Germany
| | - Dominique Thomas
- 2pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe-University, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany
| | - Caitlin N Shepard
- 3Center for Drug Discovery, Department of Pediatrics, Emory Center for AIDS Research, Emory University, Children's Healthcare of Atlanta, Atlanta, GA 30322 USA
| | - Baek Kim
- 3Center for Drug Discovery, Department of Pediatrics, Emory Center for AIDS Research, Emory University, Children's Healthcare of Atlanta, Atlanta, GA 30322 USA.,4College of Pharmacy, Kyung-Hee University, Seoul, South Korea
| | - Nerea Ferreirós
- 2pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Goethe-University, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany
| | - Thomas Gramberg
- 1Institute of Clinical and Molecular Virology, Friedrich-Alexander University Erlangen-Nürnberg, Schlossgarten 4, 91054 Erlangen, Germany
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244
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Transposable elements and the multidimensional genome. Chromosome Res 2018; 26:1-3. [DOI: 10.1007/s10577-018-9575-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 01/08/2023]
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245
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Orecchini E, Frassinelli L, Galardi S, Ciafrè SA, Michienzi A. Post-transcriptional regulation of LINE-1 retrotransposition by AID/APOBEC and ADAR deaminases. Chromosome Res 2018; 26:45-59. [PMID: 29396793 DOI: 10.1007/s10577-018-9572-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 01/07/2018] [Indexed: 02/05/2023]
Abstract
Long interspersed element-1 (LINE-1 or L1) retrotransposons represent the only functional family of autonomous transposable elements in humans and formed 17% of our genome. Even though most of the human L1 sequences are inactive, a limited number of copies per individual retain the ability to mobilize by a process termed retrotransposition. The ongoing L1 retrotransposition may result in insertional mutagenesis that could lead to negative consequences such as genetic disease and cancer. For this reason, cells have evolved several mechanisms of defense to restrict L1 activity. Among them, a critical role for cellular deaminases [activation-induced deaminase (AID)/apolipoprotein B mRNA-editing catalytic polypeptide-like (APOBEC) and adenosine deaminases that act on RNA (ADAR) enzymes] has emerged. The majority of the AID/APOBEC family of proteins are responsible for the deamination of cytosine to uracil (C-to-U editing) within DNA and RNA targets. The ADARs convert adenosine bases to inosines (A-to-I editing) within double-stranded RNA (dsRNA) targets. This review will discuss the current understanding of the regulation of LINE-1 retrotransposition mediated by these enzymes.
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Affiliation(s)
- Elisa Orecchini
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Rome, Italy
| | - Loredana Frassinelli
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Rome, Italy
| | - Silvia Galardi
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Rome, Italy
| | - Silvia Anna Ciafrè
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Rome, Italy
| | - Alessandro Michienzi
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Rome, Italy.
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246
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Klein SJ, O'Neill RJ. Transposable elements: genome innovation, chromosome diversity, and centromere conflict. Chromosome Res 2018; 26:5-23. [PMID: 29332159 PMCID: PMC5857280 DOI: 10.1007/s10577-017-9569-5] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/05/2017] [Accepted: 12/12/2017] [Indexed: 12/21/2022]
Abstract
Although it was nearly 70 years ago when transposable elements (TEs) were first discovered “jumping” from one genomic location to another, TEs are now recognized as contributors to genomic innovations as well as genome instability across a wide variety of species. In this review, we illustrate the ways in which active TEs, specifically retroelements, can create novel chromosome rearrangements and impact gene expression, leading to disease in some cases and species-specific diversity in others. We explore the ways in which eukaryotic genomes have evolved defense mechanisms to temper TE activity and the ways in which TEs continue to influence genome structure despite being rendered transpositionally inactive. Finally, we focus on the role of TEs in the establishment, maintenance, and stabilization of critical, yet rapidly evolving, chromosome features: eukaryotic centromeres. Across centromeres, specific types of TEs participate in genomic conflict, a balancing act wherein they are actively inserting into centromeric domains yet are harnessed for the recruitment of centromeric histones and potentially new centromere formation.
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Affiliation(s)
- Savannah J Klein
- Institute for Systems Genomics and Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, 06269, USA
| | - Rachel J O'Neill
- Institute for Systems Genomics and Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, 06269, USA.
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247
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Assessment of piRNA biogenesis and function in testicular germ cell tumors and their precursor germ cell neoplasia in situ. BMC Cancer 2018; 18:20. [PMID: 29301509 PMCID: PMC5755174 DOI: 10.1186/s12885-017-3945-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 12/20/2017] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Aberrant overexpression of PIWI/piRNA pathway proteins is shown for many types of tumors. Interestingly, these proteins are downregulated in testicular germ cell tumors (TGCTs) compared to normal testis tissues. Here, we used germline and TGCT markers to assess the piRNA biogenesis and function in TGCTs and their precursor germ cell neoplasia in situ (GCNIS). METHODS We used small RNA deep sequencing, qRT-PCR, and mining public RNAseq/small RNA-seq datasets to examine PIWI/piRNA gene expression and piRNA biogenesis at four stages of TGCT development: (i) germ cells in healthy testis tissues, (ii) germ cells in testis tissues adjacent to TGCTs, (iii) GCNIS cells and (iv) TGCT cells. To this end, we studied three types of samples: (a) healthy testis, (b) testis tissues adjacent to two types of TGCTs (seminomas and nonseminomas) and containing both germ cells and GCNIS cells, as well as (c) matching TGCT samples. RESULTS Based on our analyses of small RNA-seq data as well as the presence/absence of expression correlation between PIWI/piRNA pathway genes and germline or TGCT markers, we can suggest that piRNA biogenesis is intact in germ cells present in healthy adult testes, and adjacent to TGCTs. Conversely, GCNIS and TGCT cells were found to lack PIWI/piRNA pathway gene expression and germline-like piRNA biogenesis. However, using an in vitro cell line model, we revealed a possible role for a short PIWIL2/HILI isoform expressed in TGCTs in posttranscriptional regulation of the youngest members of LINE and SINE classes of transposable elements. Importantly, this regulation is also implemented without involvement of germline-like biogenesis of piRNAs. CONCLUSIONS Though further studies are warranted, these findings suggest that the conventional germline-like PIWI/piRNA pathway is lost in transition from germ cells to GCNIS cells.
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Abstract
Chromothripsis is a mutational event driven by tens to hundreds of double-stranded DNA breaks which occur in a single event between a limited number of chromosomes. Following chromosomal shattering, DNA fragments are stitched together in a seemingly random manner resulting in complex genomic rearrangements including sequence shuffling, deletions, and inversions of varying size. This genomic catastrophe has been observed in cancer genomes and the genomes of patients harboring developmental and congenital defects. The mechanisms catalyzing DNA breakage and coordinating the "random" assembly of genomic fragments are actively being investigated. Recently, retrotransposons-a type of "jumping gene"-have been implicated as one means to generate double-stranded DNA breaks during chromothripsis and as sequences which can contribute to the final configuration of the derived chromosomes. In this methods chapter, I discuss how to apply available bioinformatic tools and the hallmarks of retrotransposon mobilization to breakpoint junctions to assess the role for active and inactive retrotransposon sequences in chromothriptic events.
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Suarez NA, Macia A, Muotri AR. LINE-1 retrotransposons in healthy and diseased human brain. Dev Neurobiol 2017; 78:434-455. [PMID: 29239145 DOI: 10.1002/dneu.22567] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/07/2017] [Accepted: 12/08/2017] [Indexed: 12/12/2022]
Abstract
Long interspersed element-1 (LINE-1 or L1) is a transposable element with the ability to self-mobilize throughout the human genome. The L1 elements found in the human brain is hypothesized to date back 56 million years ago and has survived evolution, currently accounting for 17% of the human genome. L1 retrotransposition has been theorized to contribute to somatic mosaicism. This review focuses on the presence of L1 in the healthy and diseased human brain, such as in autism spectrum disorders. Throughout this exploration, we will discuss the impact L1 has on neurological disorders that can occur throughout the human lifetime. With this, we hope to better understand the complex role of L1 in the human brain development and its implications to human cognition. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 434-455, 2018.
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Affiliation(s)
- Nicole A Suarez
- Department of Pediatrics/Rady Children's Hospital San Diego, University of California San Diego, La Jolla, California, 92093
| | - Angela Macia
- Department of Pediatrics/Rady Children's Hospital San Diego, University of California San Diego, La Jolla, California, 92093
| | - Alysson R Muotri
- Department of Pediatrics/Rady Children's Hospital San Diego, University of California San Diego, La Jolla, California, 92093
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Yang P, Wang Y, Macfarlan TS. The Role of KRAB-ZFPs in Transposable Element Repression and Mammalian Evolution. Trends Genet 2017; 33:871-881. [PMID: 28935117 DOI: 10.1016/j.tig.2017.08.006] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 08/31/2017] [Accepted: 08/31/2017] [Indexed: 12/21/2022]
Abstract
Kruppel-associated box zinc-finger proteins (KRAB-ZFPs) make up the largest family of transcription factors in humans. These proteins emerged in the last common ancestor of coelacanth and tetrapods, and have expanded and diversified in the mammalian lineage. Although their mechanism of transcriptional repression has been well studied for over a decade, the DNA-binding activities and the biological functions of these proteins have been largely unexplored. Recent large-scale ChIP-seq studies and loss-of-function experiments have revealed that KRAB-ZFPs play a major role in the recognition and transcriptional silencing of transposable elements (TEs), consistent with an 'arms race model' of KRAB-ZFP evolution against invading TEs. However, this model is insufficient to explain the evolution of many KRAB-ZFPs that appear to domesticate TEs for novel host functions. We highlight some of the mammalian regulatory innovations driven by specific KRAB-ZFPs, including genomic imprinting, meiotic recombination hotspot choice, and placental growth.
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Affiliation(s)
- Peng Yang
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, MD 20892, USA
| | - Yixuan Wang
- Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai 200092, PR China
| | - Todd S Macfarlan
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, MD 20892, USA.
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