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Wallace AD, Blue NR, Morgan T, Workalemahu T, Silver RM, Quinlan AR. Placental somatic mutation in human stillbirth and live birth: A pilot case-control study of paired placental, fetal, and maternal whole genomes. Placenta 2024; 154:137-144. [PMID: 38972082 PMCID: PMC11368634 DOI: 10.1016/j.placenta.2024.06.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 06/18/2024] [Accepted: 06/19/2024] [Indexed: 07/09/2024]
Abstract
INTRODUCTION A high frequency of single nucleotide somatic mutations in the placenta has been recently described, but its relationship to placental dysfunction is unknown. METHODS We performed a pilot case-control study using paired fetal, maternal, and placental samples collected from healthy live birth controls (n = 10), live births with fetal growth restriction (FGR) due to placental insufficiency (n = 7), and stillbirths with FGR and placental insufficiency (n = 11). We quantified single nucleotide and structural somatic variants using bulk whole genome sequencing (30-60X coverage) in four biopsies from each placenta. We also assessed their association with clinical and histological evidence of placental dysfunction. RESULTS Seventeen pregnancies had sufficiently high-quality placental, fetal, and maternal DNA for analysis. Each placenta had a median of 473 variants (range 111-870), with 95 % arising in just one biopsy within each placenta. In controls, live births with FGR, and stillbirths, the median variant counts per placenta were 514 (IQR 381-779), 582 (450-735), and 338 (245-441), respectively. After adjusting for depth of sequencing coverage and gestational age at birth, the somatic mutation burden was similar between groups (FGR live births vs. controls, adjusted diff. 59, 95 % CI -218 to +336; stillbirths vs controls, adjusted diff. -34, -351 to +419), and with no association with placental dysfunction (p = 0.7). DISCUSSION We confirmed the high prevalence of somatic mutation in the human placenta and conclude that the placenta is highly clonal. We were not able to identify any relationship between somatic mutation burden and clinical or histologic placental insufficiency.
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Affiliation(s)
- Amelia D Wallace
- University of Utah Health, Department of Human Genetics, 15 N 2030 E, Eccles Institute of Human Genetics Rm 7160B, Salt Lake City, UT, 84112, USA; Utah Center for Genetic Discovery, 15 N 2030 E, #2100, Salt Lake City, UT, 4112, USA
| | - Nathan R Blue
- University of Utah Health, Department of Obstetrics and Gynecology, 30 N Mario Capecchi Dr, Level 5 South, Salt Lake City, UT, 84132, USA
| | - Terry Morgan
- Oregon Health & Science University, Departments of Pathology and Obstetrics and Gynecology, 3181 SW Sam Jackson Park Rd, L-113, Portland, OR, 97239, USA
| | - Tsegaselassie Workalemahu
- University of Utah Health, Department of Obstetrics and Gynecology, 30 N Mario Capecchi Dr, Level 5 South, Salt Lake City, UT, 84132, USA
| | - Robert M Silver
- University of Utah Health, Department of Obstetrics and Gynecology, 30 N Mario Capecchi Dr, Level 5 South, Salt Lake City, UT, 84132, USA.
| | - Aaron R Quinlan
- University of Utah Health, Department of Human Genetics, 15 N 2030 E, Eccles Institute of Human Genetics Rm 7160B, Salt Lake City, UT, 84112, USA; Utah Center for Genetic Discovery, 15 N 2030 E, #2100, Salt Lake City, UT, 4112, USA.
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Kohlrausch FB, Wang F, McKerrow W, Grivainis M, Fenyo D, Keefe DL. Mapping of long interspersed element-1 (L1) insertions by TIPseq provides information about sub chromosomal genetic variation in human embryos. J Assist Reprod Genet 2024; 41:2257-2269. [PMID: 38951360 PMCID: PMC11405744 DOI: 10.1007/s10815-024-03176-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 06/12/2024] [Indexed: 07/03/2024] Open
Abstract
PURPOSE Retrotransposons play important roles during early development when they are transiently de-repressed during epigenetic reprogramming. Long interspersed element-1 (L1), the only autonomous retrotransposon in humans, comprises 17% of the human genome. We applied the Single Cell Transposon Insertion Profiling by Sequencing (scTIPseq) to characterize and map L1 insertions in human embryos. METHODS Sixteen cryopreserved, genetically tested, human blastocysts, were accessed from consenting couples undergoing IVF at NYU Langone Fertility Center. Additionally, four trios (father, mother, and embryos) were also evaluated. scTIPseq was applied to map L1 insertions in all samples, using L1 locations reported in the 1000 Genomes as controls. RESULTS Twenty-nine unknown and unique insertions were observed in the sixteen embryos. Most were intergenic; no insertions were located in exons or immediately upstream of genes. The location or number of unknown insertions did not differ between euploid and aneuploid embryos, suggesting they are not merely markers of aneuploidy. Rather, scTIPseq provides novel information about sub-chromosomal structural variation in human embryos. Trio analyses showed a parental origin of all L1 insertions in embryos. CONCLUSION Several studies have measured L1 expression at different stages of development in mice, but this study for the first time reports unknown insertions in human embryos that were inherited from one parent, confirming no de novo L1 insertions occurred in parental germline or during embryogenesis. Since one-third of euploid embryo transfers fail, future studies would be useful for understanding whether these sub-chromosomal genetic variants or de novo L1 insertions affect embryo developmental potential.
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Affiliation(s)
- Fabiana B Kohlrausch
- Departamento de Biologia Geral, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, 24210-201, Brazil.
- Department of Obstetrics and Gynecology, New York University, New York, NY, 10016, USA.
| | - Fang Wang
- Department of Obstetrics and Gynecology, New York University, New York, NY, 10016, USA
| | - Wilson McKerrow
- Institute for Systems Genetics, New York University, New York, NY, 10016, USA
| | - Mark Grivainis
- Institute for Systems Genetics, New York University, New York, NY, 10016, USA
| | - David Fenyo
- Institute for Systems Genetics, New York University, New York, NY, 10016, USA
| | - David L Keefe
- Department of Obstetrics and Gynecology, New York University, New York, NY, 10016, USA
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Moadab F, Sohrabi S, Wang X, Najjar R, Wolters JC, Jiang H, Miao W, Romero D, Zaller DM, Tran M, Bays A, Taylor MS, Kapeller R, LaCava J, Mustelin T. Subcellular location of L1 retrotransposon-encoded ORF1p, reverse transcription products, and DNA sensors in lupus granulocytes. Mob DNA 2024; 15:14. [PMID: 38937837 PMCID: PMC11212426 DOI: 10.1186/s13100-024-00324-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 06/18/2024] [Indexed: 06/29/2024] Open
Abstract
BACKGROUND Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with an unpredictable course of recurrent exacerbations alternating with more stable disease. SLE is characterized by broad immune activation and autoantibodies against double-stranded DNA and numerous proteins that exist in cells as aggregates with nucleic acids, such as Ro60, MOV10, and the L1 retrotransposon-encoded ORF1p. RESULTS Here we report that these 3 proteins are co-expressed and co-localized in a subset of SLE granulocytes and are concentrated in cytosolic dots that also contain DNA: RNA heteroduplexes and the DNA sensor ZBP1, but not cGAS. The DNA: RNA heteroduplexes vanished from the neutrophils when they were treated with a selective inhibitor of the L1 reverse transcriptase. We also report that ORF1p granules escape neutrophils during the extrusion of neutrophil extracellular traps (NETs) and, to a lesser degree, from neutrophils dying by pyroptosis, but not apoptosis. CONCLUSIONS These results bring new insights into the composition of ORF1p granules in SLE neutrophils and may explain, in part, why proteins in these granules become targeted by autoantibodies in this disease.
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Affiliation(s)
- Fatemeh Moadab
- Division of Rheumatology, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Sepideh Sohrabi
- Division of Rheumatology, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Xiaoxing Wang
- Division of Rheumatology, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Rayan Najjar
- Division of Rheumatology, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Justina C Wolters
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Hua Jiang
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA
| | | | | | | | - Megan Tran
- Division of Rheumatology, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Alison Bays
- Division of Rheumatology, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Martin S Taylor
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | - John LaCava
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, Groningen, The Netherlands
| | - Tomas Mustelin
- Division of Rheumatology, Department of Medicine, University of Washington, Seattle, WA, USA.
- University of Washington, 750 Republican Street, Room E507, Seattle, WA, 98109, USA.
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Fu B, Ma H, Liu D. Pioneer Transcription Factors: The First Domino in Zygotic Genome Activation. Biomolecules 2024; 14:720. [PMID: 38927123 PMCID: PMC11202083 DOI: 10.3390/biom14060720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 05/31/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
Zygotic genome activation (ZGA) is a pivotal event in mammalian embryogenesis, marking the transition from maternal to zygotic control of development. During the ZGA process that is characterized by the intricate cascade of gene expression, who tipped the first domino in a meticulously arranged sequence is a subject of paramount interest. Recently, Dux, Obox and Nr5a2 were identified as pioneer transcription factors that reside at the top of transcriptional hierarchy. Through co-option of retrotransposon elements as hubs for transcriptional activation, these pioneer transcription factors rewire the gene regulatory network, thus initiating ZGA. In this review, we provide a snapshot of the mechanisms underlying the functions of these pioneer transcription factors. We propose that ZGA is the starting point where the embryo's own genome begins to influence development trajectory, therefore in-depth dissecting the functions of pioneer transcription factors during ZGA will form a cornerstone of our understanding for early embryonic development, which will pave the way for advancing our grasp of mammalian developmental biology and optimizing in vitro production (IVP) techniques.
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Affiliation(s)
- Bo Fu
- Institute of Animal Husbandry, HeiLongJiang Academy of Agricultural Sciences, Harbin 150086, China; (B.F.); (H.M.)
- Key Laboratory of Combining Farming and Animal Husbandry, Ministry of Agriculture and Rural Affairs, Harbin 150086, China
| | - Hong Ma
- Institute of Animal Husbandry, HeiLongJiang Academy of Agricultural Sciences, Harbin 150086, China; (B.F.); (H.M.)
- Key Laboratory of Combining Farming and Animal Husbandry, Ministry of Agriculture and Rural Affairs, Harbin 150086, China
| | - Di Liu
- Institute of Animal Husbandry, HeiLongJiang Academy of Agricultural Sciences, Harbin 150086, China; (B.F.); (H.M.)
- Key Laboratory of Combining Farming and Animal Husbandry, Ministry of Agriculture and Rural Affairs, Harbin 150086, China
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Kojima S. Investigating mobile element variations by statistical genetics. Hum Genome Var 2024; 11:23. [PMID: 38816353 PMCID: PMC11140006 DOI: 10.1038/s41439-024-00280-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/17/2024] [Accepted: 04/24/2024] [Indexed: 06/01/2024] Open
Abstract
The integration of structural variations (SVs) in statistical genetics provides an opportunity to understand the genetic factors influencing complex human traits and disease. Recent advances in long-read technology and variant calling methods for short reads have improved the accurate discovery and genotyping of SVs, enabling their use in expression quantitative trait loci (eQTL) analysis and genome-wide association studies (GWAS). Mobile elements are DNA sequences that insert themselves into various genome locations. Insertional polymorphisms of mobile elements between humans, called mobile element variations (MEVs), contribute to approximately 25% of human SVs. We recently developed a variant caller that can accurately identify and genotype MEVs from biobank-scale short-read whole-genome sequencing (WGS) datasets and integrate them into statistical genetics. The use of MEVs in eQTL analysis and GWAS has a minimal impact on the discovery of genome loci associated with gene expression and disease; most disease-associated haplotypes can be identified by single nucleotide variations (SNVs). On the other hand, it helps make hypotheses about causal variants or effector variants. Focusing on MEVs, we identified multiple MEVs that contribute to differential gene expression and one of them is a potential cause of skin disease, emphasizing the importance of the integration of MEVs in medical genetics. Here, I will provide an overview of MEVs, MEV calling from WGS, and the integration of MEVs in statistical genetics. Finally, I will discuss the unanswered questions about MEVs, such as rare variants.
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Affiliation(s)
- Shohei Kojima
- Genome Immunobiology RIKEN Hakubi Research Team, RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan.
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6
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Tang W, Liang P. The identification of retro-DNAs in primate genomes as DNA transposons mobilizing via retrotransposition. F1000Res 2024; 12:255. [PMID: 38915770 PMCID: PMC11195612 DOI: 10.12688/f1000research.130043.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/23/2024] [Indexed: 06/26/2024] Open
Abstract
Background Mobile elements (MEs) constitute a major portion of the genome in primates and other higher eukaryotes, and they play important role in genome evolution and gene function. MEs can be divided into two fundamentally different classes: DNA transposons which transpose in the genome in a "cut-and-paste" style, and retrotransposons which propagate in a "copy-and-paste" fashion via a process involving transcription and reverse-transcription. In primate genomes, DNA transposons are mostly dead, while many retrotransposons are still highly active. We report here the identification of a unique group of MEs, which we call "retro-DNAs", for their combined characteristics of these two fundamentally different ME classes. Methods A comparative computational genomic approach was used to analyze the reference genome sequences of 10 primate species consisting of five apes, four monkeys, and marmoset. Results From our analysis, we identified a total of 1,750 retro-DNAs, representing 748 unique insertion events in the genomes of ten primate species including human. These retro-DNAs contain sequences of DNA transposons but lack the terminal inverted repeats (TIRs), the hallmark of DNA transposons. Instead, they show characteristics of retrotransposons, such as polyA tails, longer target-site duplications (TSDs), and the "TT/AAAA" insertion site motif, suggesting the use of the L1-based target- primed reverse transcription (TPRT) mechanism. At least 40% of these retro-DNAs locate into genic regions, presenting potentials for impacting gene function. More interestingly, some retro-DNAs, as well as their parent sites, show certain levels of expression, suggesting that they have the potential to create more retro-DNA copies in the present primate genomes. Conclusions Although small in number, the identification of these retro-DNAs reveals a new mean for propagating DNA transposons in primate genomes without active canonical DNA transposon activity. Our data also suggest that the TPRT machinery may transpose a wider variety of DNA sequences in the genomes.
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Affiliation(s)
- Wangxiangfu Tang
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, L2S 3A1, Canada
| | - Ping Liang
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, L2S 3A1, Canada
- Centre of Biotechnology, Brock University, St. Catharines, Ontario, L2S 3A1, Canada
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D'Ordine AM, Jogl G, Sedivy JM. Identification and characterization of small molecule inhibitors of the LINE-1 retrotransposon endonuclease. Nat Commun 2024; 15:3883. [PMID: 38719805 PMCID: PMC11078990 DOI: 10.1038/s41467-024-48066-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 04/18/2024] [Indexed: 05/12/2024] Open
Abstract
The long interspersed nuclear element-1 (LINE-1 or L1) retrotransposon is the only active autonomously replicating retrotransposon in the human genome. L1 harms the cell by inserting new copies, generating DNA damage, and triggering inflammation. Therefore, L1 inhibition could be used to treat many diseases associated with these processes. Previous research has focused on inhibition of the L1 reverse transcriptase due to the prevalence of well-characterized inhibitors of related viral enzymes. Here we present the L1 endonuclease as another target for reducing L1 activity. We characterize structurally diverse small molecule endonuclease inhibitors using computational, biochemical, and biophysical methods. We also show that these inhibitors reduce L1 retrotransposition, L1-induced DNA damage, and inflammation reinforced by L1 in senescent cells. These inhibitors could be used for further pharmacological development and as tools to better understand the life cycle of this element and its impact on disease processes.
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Affiliation(s)
- Alexandra M D'Ordine
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
- Center on the Biology of Aging, Brown University, Providence, RI, USA
| | - Gerwald Jogl
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA.
- Center on the Biology of Aging, Brown University, Providence, RI, USA.
| | - John M Sedivy
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA.
- Center on the Biology of Aging, Brown University, Providence, RI, USA.
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Loomans-Kropp HA. The utility of liquid biopsy-based methylation biomarkers for colorectal cancer detection. Front Oncol 2024; 14:1351514. [PMID: 38595823 PMCID: PMC11002156 DOI: 10.3389/fonc.2024.1351514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 03/13/2024] [Indexed: 04/11/2024] Open
Abstract
Colorectal cancer (CRC) is one of the most prevalent cancers and the second leading cause of cancer-related deaths in the United States. It is also one of the few cancers with established screening guidelines, however these methods have significant patient burden (e.g., time, invasive). In recent years, the development of liquid biopsy-based screening methods for biomarker detection have emerged as alternatives to traditional screening. Methylation biomarkers are of particular interest, and these markers can be identified and measured on circulating tumor and cell-free DNA. This perspective summarizes the current state of CRC screening and the potential integration of DNA methylation markers into liquid biopsy-based techniques. Finally, I discuss limitations to these methods and strategies for improvement. The continued development and implementation of liquid biopsy-based cancer screening approaches may provide an acceptable alternative to individuals unwilling to be screened by traditional methods.
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Affiliation(s)
- Holli A. Loomans-Kropp
- Cancer Control Program, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, The Ohio State University, Columbus, OH, United States
- Division of Cancer Prevention and Control, Department of Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH, United States
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Matsushima W, Planet E, Trono D. Ancestral genome reconstruction enhances transposable element annotation by identifying degenerate integrants. CELL GENOMICS 2024; 4:100497. [PMID: 38295789 PMCID: PMC10879028 DOI: 10.1016/j.xgen.2024.100497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 08/09/2023] [Accepted: 01/06/2024] [Indexed: 02/17/2024]
Abstract
Growing evidence indicates that transposable elements (TEs) play important roles in evolution by providing genomes with coding and non-coding sequences. Identification of TE-derived functional elements, however, has relied on TE annotations in individual species, which limits its scope to relatively intact TE sequences. Here, we report a novel approach to uncover previously unannotated degenerate TEs (degTEs) by probing multiple ancestral genomes reconstructed from hundreds of species. We applied this method to the human genome and achieved a 10.8% increase in coverage over the most recent annotation. Further, we discovered that degTEs contribute to various cis-regulatory elements and transcription factor binding sites, including those of a known TE-controlling family, the KRAB zinc-finger proteins. We also report unannotated chimeric transcripts between degTEs and human genes expressed in embryos. This study provides a novel methodology and a freely available resource that will facilitate the investigation of TE co-option events on a full scale.
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Affiliation(s)
- Wayo Matsushima
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Evarist Planet
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Didier Trono
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
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Mathavarajah S, Dellaire G. LINE-1: an emerging initiator of cGAS-STING signalling and inflammation that is dysregulated in disease. Biochem Cell Biol 2024; 102:38-46. [PMID: 37643478 DOI: 10.1139/bcb-2023-0134] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023] Open
Abstract
The cGAS-STING (cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING)) axis integrates DNA damage and cellular stress with type I interferon (IFN) signalling to facilitate transcriptional changes underlying inflammatory stress responses. The cGAS-STING pathway responds to cytosolic DNA in the form of double-stranded DNA, micronuclei, and long interspersed nuclear element 1 (L1) retroelements. L1 retroelements are a class of self-propagating non-long terminal repeat transposons that have remained highly active in mammalian genomes. L1 retroelements are emerging as important inducers of cGAS-STING and IFN signalling, which are often dysregulated in several diseases, including cancer. A key repressor of cGAS-STING and L1 activity is the exonuclease three prime repair exonuclease 1 (TREX1), and loss of TREX1 promotes the accumulation of L1. In addition, L1 dysregulation is a common theme among diseases with chronic induction of type I IFN signalling through cGAS-STING, such as Aicardi-Goutières syndrome, Fanconi anemia, and dermatomyositis. Although TREX1 is highly conserved in tetrapod species, other suppressor proteins exist that inhibit L1 retrotransposition. These suppressor genes when mutated are often associated with diseases characterized by unchecked inflammation that is associated with high cGAS-STING activity and elevated levels of L1 expression. In this review, we discuss these interconnected pathways of L1 suppression and their role in the regulation of cGAS-STING and inflammation in disease.
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Affiliation(s)
| | - Graham Dellaire
- Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
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Sala L, Kumar M, Prajapat M, Chandrasekhar S, Cosby RL, La Rocca G, Macfarlan TS, Awasthi P, Chari R, Kruhlak M, Vidigal JA. AGO2 silences mobile transposons in the nucleus of quiescent cells. Nat Struct Mol Biol 2023; 30:1985-1995. [PMID: 37985687 DOI: 10.1038/s41594-023-01151-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 09/27/2023] [Indexed: 11/22/2023]
Abstract
Argonaute 2 (AGO2) is a cytoplasmic component of the miRNA pathway, with essential roles in development and disease. Yet little is known about its regulation in vivo. Here we show that in quiescent mouse splenocytes, AGO2 localizes almost exclusively to the nucleus. AGO2 subcellular localization is modulated by the Pi3K-AKT-mTOR pathway, a well-established regulator of quiescence. Signaling through this pathway in proliferating cells promotes AGO2 cytoplasmic accumulation, at least in part by stimulating the expression of TNRC6, an essential AGO2 binding partner in the miRNA pathway. In quiescent cells in which mTOR signaling is low, AGO2 accumulates in the nucleus, where it binds to young mobile transposons co-transcriptionally to repress their expression via its catalytic domain. Our data point to an essential but previously unrecognized nuclear role for AGO2 during quiescence as part of a genome-defense system against young mobile elements and provide evidence of RNA interference in the soma of mammals.
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Affiliation(s)
- Laura Sala
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, The National Institutes of Health, Bethesda, MD, USA
| | - Manish Kumar
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, The National Institutes of Health, Bethesda, MD, USA
| | - Mahendra Prajapat
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, The National Institutes of Health, Bethesda, MD, USA
| | - Srividya Chandrasekhar
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, The National Institutes of Health, Bethesda, MD, USA
| | - Rachel L Cosby
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, MD, USA
- The National Institute for General Medical Sciences, The National Institutes of Health, Bethesda, MD, USA
| | - Gaspare La Rocca
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Todd S Macfarlan
- The Eunice Kennedy Shriver National Institute of Child Health and Human Development, The National Institutes of Health, Bethesda, MD, USA
| | - Parirokh Awasthi
- Laboratory Animal Sciences Program, Frederick National Lab for Cancer Research, The National Institutes of Health, Frederick, MD, USA
| | - Raj Chari
- Laboratory Animal Sciences Program, Frederick National Lab for Cancer Research, The National Institutes of Health, Frederick, MD, USA
| | - Michael Kruhlak
- CCR Confocal Microscopy Core Facility, National Cancer Institute, The National Institutes of Health, Bethesda, MD, USA
| | - Joana A Vidigal
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, The National Institutes of Health, Bethesda, MD, USA.
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Vylegzhanina AV, Bespalov IA, Novototskaya-Vlasova KA, Hall BM, Gleiberman AS, Yu H, Leontieva OV, Leonova KI, Kurnasov OV, Osterman AL, Dy GK, Komissarov AA, Vasilieva E, Gehlhausen J, Iwasaki A, Ambrosone CB, Tsuji T, Matsuzaki J, Odunsi K, Andrianova EL, Gudkov AV. Cancer Relevance of Circulating Antibodies Against LINE-1 Antigens in Humans. CANCER RESEARCH COMMUNICATIONS 2023; 3:2256-2267. [PMID: 37870410 PMCID: PMC10631453 DOI: 10.1158/2767-9764.crc-23-0289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/16/2023] [Accepted: 10/13/2023] [Indexed: 10/24/2023]
Abstract
Long interspersed nuclear element-1 (LINE-1 or L1), the most abundant family of autonomous retrotransposons occupying over 17% of human DNA, is epigenetically silenced in normal tissues by the mechanisms involving p53 but is frequently derepressed in cancer, suggesting that L1-encoded proteins may act as tumor-associated antigens recognized by the immune system. In this study, we established an immunoassay to detect circulating autoantibodies against L1 proteins in human blood. Using this assay in >2,800 individuals with or without cancer, we observed significantly higher IgG titers against L1-encoded ORF1p and ORF2p in patients with lung, pancreatic, ovarian, esophageal, and liver cancers than in healthy individuals. Remarkably, elevated levels of anti-ORF1p-reactive IgG were observed in patients with cancer with disease stages 1 and 2, indicating that the immune response to L1 antigens can occur in the early phases of carcinogenesis. We concluded that the antibody response against L1 antigens could contribute to the diagnosis and determination of immunoreactivity of tumors among cancer types that frequently escape early detection. SIGNIFICANCE The discovery of autoantibodies against antigens encoded by L1 retrotransposons in patients with five poorly curable cancer types has potential implications for the detection of an ongoing carcinogenic process and tumor immunoreactivity.
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Affiliation(s)
| | | | | | | | | | - Han Yu
- Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | | | | | - Oleg V. Kurnasov
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Andrei L. Osterman
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Grace K. Dy
- Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Alexey A. Komissarov
- I.V. Davydovsky Clinical City Hospital, Moscow, Russia
- A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow, Russia
| | - Elena Vasilieva
- I.V. Davydovsky Clinical City Hospital, Moscow, Russia
- A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow, Russia
| | | | - Akiko Iwasaki
- Yale University, New Haven, Connecticut
- Howard Hughes Medical Institute, Chevy Chase, Maryland
| | | | - Takemasa Tsuji
- University of Chicago Medicine Comprehensive Cancer Center, Chicago, Illinois
| | - Junko Matsuzaki
- University of Chicago Medicine Comprehensive Cancer Center, Chicago, Illinois
| | - Kunle Odunsi
- University of Chicago Medicine Comprehensive Cancer Center, Chicago, Illinois
| | | | - Andrei V. Gudkov
- Genome Protection, Inc., Buffalo, New York
- Roswell Park Comprehensive Cancer Center, Buffalo, New York
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Michalak TI. The Initial Hepatitis B Virus-Hepatocyte Genomic Integrations and Their Role in Hepatocellular Oncogenesis. Int J Mol Sci 2023; 24:14849. [PMID: 37834296 PMCID: PMC10573506 DOI: 10.3390/ijms241914849] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 09/30/2023] [Accepted: 09/30/2023] [Indexed: 10/15/2023] Open
Abstract
Hepatitis B virus (HBV) remains a dominant cause of hepatocellular carcinoma (HCC). Recently, it was shown that HBV and woodchuck hepatitis virus (WHV) integrate into the hepatocyte genome minutes after invasion. Retrotransposons and transposable sequences were frequent sites of the initial insertions, suggesting a mechanism for spontaneous HBV DNA dispersal throughout the hepatocyte genome. Several somatic genes were also identified as early insertional targets in infected hepatocytes and woodchuck livers. Head-to-tail joints (HTJs) dominated amongst fusions, indicating their creation by non-homologous end-joining (NHEJ). Their formation coincided with the robust oxidative damage of hepatocyte DNA. This was associated with the activation of poly(ADP-ribose) polymerase 1 (PARP1)-mediated dsDNA repair, as reflected by the augmented transcription of PARP1 and XRCC1; the PARP1 binding partner OGG1, a responder to oxidative DNA damage; and increased activity of NAD+, a marker of PARP1 activation, and HO1, an indicator of cell oxidative stress. The engagement of the PARP1-mediated NHEJ repair pathway explains the HTJ format of the initial merges. The findings show that HBV and WHV are immediate inducers of oxidative DNA damage and hijack dsDNA repair to integrate into the hepatocyte genome, and through this mechanism, they may initiate pro-oncogenic processes. Tracking initial integrations may uncover early markers of HCC and help to explain HBV-associated oncogenesis.
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Affiliation(s)
- Tomasz I Michalak
- Molecular Virology and Hepatology Research Group, Division of BioMedical Science, Faculty of Medicine, Health Science Center, Memorial University of Newfoundland, St. John's, NL A1B 3V6, Canada
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Mauro M, Wei S, Breborowicz A, Li X, Bognanni C, Fuller Z, Philipp T, McDonald T, Lattin MT, Williams Z. Endogenous retrotransposons cause catastrophic deoxyribonucleic acid damage in human trophoblasts. F&S SCIENCE 2023; 4:200-210. [PMID: 37225003 DOI: 10.1016/j.xfss.2023.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 05/15/2023] [Accepted: 05/18/2023] [Indexed: 05/26/2023]
Abstract
OBJECTIVE To determine the mechanistic role of mobile genetic elements in causing widespread DNA damage in primary human trophoblasts. DESIGN Experimental ex vivo study. SETTING Hospital-affiliated University. PATIENT(S) Trophoblasts from a patient with unexplained recurrent pregnancy loss and patients with spontaneous and elective abortions (n = 10). INTERVENTION(S) Biochemical and genetic analysis and modification of primary human trophoblasts. MAIN OUTCOME MEASURE(S) To phenotype and systematically evaluate the underlying pathogenic mechanism for elevated DNA damage observed in trophoblasts derived from a patient with unexplained recurrent pregnancy loss, transcervical embryoscopy, G-band karyotyping, RNA sequencing, quantitative polymerase chain reaction, immunoblotting, biochemical and siRNA assays, and whole-genome sequencing were performed. RESULT(S) Transcervical embryoscopy revealed a severely dysmorphic embryo that was euploid on G-band karyotyping. RNA sequencing was notable for markedly elevated LINE-1 expression, confirmed with quantitative polymerase chain reaction, and that resulted in elevated expression of LINE-1-encoded proteins, as shown by immunoblotting. Immunofluorescence, biochemical and genetic approaches demonstrated that overexpression of LINE-1 caused reversible widespread genomic damage and apoptosis. CONCLUSION(S) Derepression of LINE-1 elements in early trophoblasts results in reversible but widespread DNA damage.
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Affiliation(s)
- Maurizio Mauro
- Department of Obstetrics and Gynecology, Columbia University Fertility Center, Columbia University Medical Center, New York, New York; Department of Obstetrics and Gynecology and Women's Health, Albert Einstein College of Medicine, Bronx, New York
| | - Shan Wei
- Department of Obstetrics and Gynecology, Columbia University Fertility Center, Columbia University Medical Center, New York, New York
| | - Andrzej Breborowicz
- Department of Obstetrics and Gynecology and Women's Health, Albert Einstein College of Medicine, Bronx, New York
| | - Xin Li
- Department of Obstetrics and Gynecology and Women's Health, Albert Einstein College of Medicine, Bronx, New York
| | - Claudia Bognanni
- The Rockefeller University, Howard Hughes Medical Institute, and Laboratory of RNA Molecular Biology, New York, New York
| | - Zachary Fuller
- Department of Biological Sciences, Columbia University, New York, New York
| | - Thomas Philipp
- Institute of Clinical Gynecology and Obstetrics, Danube Hospital, Vienna, Austria
| | - Torrin McDonald
- Department of Obstetrics and Gynecology, Columbia University Fertility Center, Columbia University Medical Center, New York, New York
| | - Miriam Temmeh Lattin
- Department of Obstetrics and Gynecology, Columbia University Fertility Center, Columbia University Medical Center, New York, New York
| | - Zev Williams
- Department of Obstetrics and Gynecology, Columbia University Fertility Center, Columbia University Medical Center, New York, New York.
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15
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Spirito G, Filosi M, Domenici E, Mangoni D, Gustincich S, Sanges R. Exploratory analysis of L1 retrotransposons expression in autism. Mol Autism 2023; 14:22. [PMID: 37381037 DOI: 10.1186/s13229-023-00554-5] [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: 11/03/2022] [Accepted: 06/15/2023] [Indexed: 06/30/2023] Open
Abstract
BACKGROUND Autism spectrum disorder (ASD) is a set of highly heterogeneous neurodevelopmental diseases whose genetic etiology is not completely understood. Several investigations have relied on transcriptome analysis from peripheral tissues to dissect ASD into homogenous molecular phenotypes. Recently, analysis of changes in gene expression from postmortem brain tissues has identified sets of genes that are involved in pathways previously associated with ASD etiology. In addition to protein-coding transcripts, the human transcriptome is composed by a large set of non-coding RNAs and transposable elements (TEs). Advancements in sequencing technologies have proven that TEs can be transcribed in a regulated fashion, and their dysregulation might have a role in brain diseases. METHODS We exploited published datasets comprising RNA-seq data from (1) postmortem brain of ASD subjects, (2) in vitro cell cultures where ten different ASD-relevant genes were knocked out and (3) blood of discordant siblings. We measured the expression levels of evolutionarily young full-length transposable L1 elements and characterized the genomic location of deregulated L1s assessing their potential impact on the transcription of ASD-relevant genes. We analyzed every sample independently, avoiding to pool together the disease subjects to unmask the heterogeneity of the molecular phenotypes. RESULTS We detected a strong upregulation of intronic full-length L1s in a subset of postmortem brain samples and in in vitro differentiated neurons from iPSC knocked out for ATRX. L1 upregulation correlated with an high number of deregulated genes and retained introns. In the anterior cingulate cortex of one subject, a small number of significantly upregulated L1s overlapped with ASD-relevant genes that were significantly downregulated, suggesting the possible existence of a negative effect of L1 transcription on host transcripts. LIMITATIONS Our analyses must be considered exploratory and will need to be validated in bigger cohorts. The main limitation is given by the small sample size and by the lack of replicates for postmortem brain samples. Measuring the transcription of locus-specific TEs is complicated by the repetitive nature of their sequence, which reduces the accuracy in mapping sequencing reads to the correct genomic locus. CONCLUSIONS L1 upregulation in ASD appears to be limited to a subset of subjects that are also characterized by a general deregulation of the expression of canonical genes and an increase in intron retention. In some samples from the anterior cingulate cortex, L1s upregulation seems to directly impair the expression of some ASD-relevant genes by a still unknown mechanism. L1s upregulation may therefore identify a group of ASD subjects with common molecular features and helps stratifying individuals for novel strategies of therapeutic intervention.
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Affiliation(s)
- Giovanni Spirito
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Area of Neuroscience, Via Bonomea 265, 34136, Trieste, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia - IIT, Via Enrico Melen 83, Building B, 16152, Genoa, Italy
- CMP3vda, Via Lavoratori Vittime del Col Du Mont 28, Aosta, Italy
| | - Michele Filosi
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, TN, Italy
- Eurac Research, Institute for Biomedicine, Bolzano, BZ, Italy
| | - Enrico Domenici
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, TN, Italy
- Fondazione The Microsoft Research - University of Trento Centre for Computational and Systems Biology (COSBI), Rovereto, TN, Italy
| | - Damiano Mangoni
- Central RNA Laboratory, Istituto Italiano di Tecnologia - IIT, Via Enrico Melen 83, Building B, 16152, Genoa, Italy
| | - Stefano Gustincich
- Central RNA Laboratory, Istituto Italiano di Tecnologia - IIT, Via Enrico Melen 83, Building B, 16152, Genoa, Italy.
- CMP3vda, Via Lavoratori Vittime del Col Du Mont 28, Aosta, Italy.
| | - Remo Sanges
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Area of Neuroscience, Via Bonomea 265, 34136, Trieste, Italy.
- Central RNA Laboratory, Istituto Italiano di Tecnologia - IIT, Via Enrico Melen 83, Building B, 16152, Genoa, Italy.
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16
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De Luca C, Gupta A, Bortvin A. Retrotransposon LINE-1 bodies in the cytoplasm of piRNA-deficient mouse spermatocytes: Ribonucleoproteins overcoming the integrated stress response. PLoS Genet 2023; 19:e1010797. [PMID: 37307272 DOI: 10.1371/journal.pgen.1010797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 05/23/2023] [Indexed: 06/14/2023] Open
Abstract
Transposable elements (TE) are mobile DNA sequences whose excessive proliferation endangers the host. Although animals have evolved robust TE-targeting defenses, including Piwi-interacting (pi)RNAs, retrotransposon LINE-1 (L1) still thrives in humans and mice. To gain insights into L1 endurance, we characterized L1 Bodies (LBs) and ORF1p complexes in germ cells of piRNA-deficient Maelstrom null mice. We report that ORF1p interacts with TE RNAs, genic mRNAs, and stress granule proteins, consistent with earlier studies. We also show that ORF1p associates with the CCR4-NOT deadenylation complex and PRKRA, a Protein Kinase R factor. Despite ORF1p interactions with these negative regulators of RNA expression, the stability and translation of LB-localized mRNAs remain unchanged. To scrutinize these findings, we studied the effects of PRKRA on L1 in cultured cells and showed that it elevates ORF1p levels and L1 retrotransposition. These results suggest that ORF1p-driven condensates promote L1 propagation, without affecting the metabolism of endogenous RNAs.
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Affiliation(s)
- Chiara De Luca
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, United States of Americ
| | - Anuj Gupta
- The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alex Bortvin
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, United States of Americ
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17
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Batcher K, Varney S, Raudsepp T, Jevit M, Dickinson P, Jagannathan V, Leeb T, Bannasch D. Ancient segmentally duplicated LCORL retrocopies in equids. PLoS One 2023; 18:e0286861. [PMID: 37289743 PMCID: PMC10249811 DOI: 10.1371/journal.pone.0286861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 05/25/2023] [Indexed: 06/10/2023] Open
Abstract
LINE-1 is an active transposable element encoding proteins capable of inserting host gene retrocopies, resulting in retro-copy number variants (retroCNVs) between individuals. Here, we performed retroCNV discovery using 86 equids and identified 437 retrocopy insertions. Only 5 retroCNVs were shared between horses and other equids, indicating that the majority of retroCNVs inserted after the species diverged. A large number (17-35 copies) of segmentally duplicated Ligand Dependent Nuclear Receptor Corepressor Like (LCORL) retrocopies were present in all equids but absent from other extant perissodactyls. The majority of LCORL transcripts in horses and donkeys originate from the retrocopies. The initial LCORL retrotransposition occurred 18 million years ago (17-19 95% CI), which is coincident with the increase in body size, reduction in digit number, and changes in dentition that characterized equid evolution. Evolutionary conservation of the LCORL retrocopy segmental amplification in the Equidae family, high expression levels and the ancient timeline for LCORL retrotransposition support a functional role for this structural variant.
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Affiliation(s)
- Kevin Batcher
- Department of Population Health and Reproduction, University of California Davis, Davis, CA, United States of America
| | - Scarlett Varney
- Department of Population Health and Reproduction, University of California Davis, Davis, CA, United States of America
| | - Terje Raudsepp
- Veterinary Integrative Biosciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
| | - Matthew Jevit
- Veterinary Integrative Biosciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States of America
| | - Peter Dickinson
- Department of Surgical and Radiological Sciences, University of California Davis, Davis, CA, United States of America
| | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Tosso Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Danika Bannasch
- Department of Population Health and Reproduction, University of California Davis, Davis, CA, United States of America
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18
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Du Q, Stow EC, LaCoste D, Freeman B, Baddoo M, Shareef A, Miller KM, Belancio VP. A novel role of TRIM28 B box domain in L1 retrotransposition and ORF2p-mediated cDNA synthesis. Nucleic Acids Res 2023; 51:4429-4450. [PMID: 37070200 PMCID: PMC10201437 DOI: 10.1093/nar/gkad247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 03/22/2023] [Accepted: 03/25/2023] [Indexed: 04/19/2023] Open
Abstract
The long interspersed element 1 (LINE-1 or L1) integration is affected by many cellular factors through various mechanisms. Some of these factors are required for L1 amplification, while others either suppress or enhance specific steps during L1 propagation. Previously, TRIM28 has been identified to suppress transposable elements, including L1 expression via its canonical role in chromatin remodeling. Here, we report that TRIM28 through its B box domain increases L1 retrotransposition and facilitates shorter cDNA and L1 insert generation in cultured cells. Consistent with the latter, we observe that tumor specific L1 inserts are shorter in endometrial, ovarian, and prostate tumors with higher TRIM28 mRNA expression than in those with lower TRIM28 expression. We determine that three amino acids in the B box domain that are involved in TRIM28 multimerization are critical for its effect on both L1 retrotransposition and cDNA synthesis. We provide evidence that B boxes from the other two members in the Class VI TRIM proteins, TRIM24 and TRIM33, also increase L1 retrotransposition. Our findings could lead to a better understanding of the host/L1 evolutionary arms race in the germline and their interplay during tumorigenesis.
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Affiliation(s)
- Qianhui Du
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans 70112, USA
| | - Emily C Stow
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans 70112, USA
| | - Dawn LaCoste
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans 70112, USA
| | - Benjamin Freeman
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans 70112, USA
| | - Melody Baddoo
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
| | - Afzaal M Shareef
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans 70112, USA
| | - Kyle M Miller
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas at Austin, 100 E 24th Street, Austin, TX 78712, USA
| | - Victoria P Belancio
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans 70112, USA
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19
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Fujita M, Goto M, Tanaka M, Yoshida W. Detection of CpG methylation level using methyl-CpG-binding domain-fused fluorescent protein. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2023; 15:2294-2299. [PMID: 37010025 DOI: 10.1039/d3ay00227f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Methylation of cytosine to 5-methylcytosine on CpG dinucleotides is the most frequently studied epigenetic modification involved in the regulation of gene expression. In normal tissues, tissue-specific CpG methylation patterns are established during development. In contrast, alterations in methylation patterns have been observed in abnormal cells, such as cancer cells. Cancer type-specific CpG methylation patterns have been identified and used as biomarkers for cancer diagnosis. In this study, we developed a hybridization-based CpG methylation level sensing system using a methyl-CpG-binding domain (MBD)-fused fluorescent protein. In this system, the target DNA is captured by a complementary methylated probe DNA. When the target DNA is methylated, a symmetrically methylated CpG is formed in the double-stranded DNA. MBD specifically recognizes symmetrical methyl-CpG on double-stranded DNA; therefore, the methylation level is quantified by measuring the fluorescence intensity of the bound MBD-fused fluorescent protein. We prepared MBD-fused AcGFP1 and quantified the CpG methylation levels of the target DNA against SEPT9, BRCA1, and long interspersed nuclear element-1 (LINE-1) using MBD-AcGFP1. This detection principle can be applied to the simultaneous and genome-wide modified base detection systems using microarrays coupled with modified base binding proteins fused to fluorescent proteins.
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Affiliation(s)
- Marika Fujita
- Graduate School of Bionics, Tokyo University of Technology, 1404-1 Katakuramachi, Hachioji, Tokyo, 192-0982, Japan.
| | - Masanori Goto
- Graduate School of Bionics, Tokyo University of Technology, 1404-1 Katakuramachi, Hachioji, Tokyo, 192-0982, Japan.
| | - Masayoshi Tanaka
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8503, Japan.
| | - Wataru Yoshida
- Graduate School of Bionics, Tokyo University of Technology, 1404-1 Katakuramachi, Hachioji, Tokyo, 192-0982, Japan.
- School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakuramachi, Hachioji, Tokyo, 192-0982, Japan
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20
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Nam CH, Youk J, Kim JY, Lim J, Park JW, Oh SA, Lee HJ, Park JW, Won H, Lee Y, Jeong SY, Lee DS, Oh JW, Han J, Lee J, Kwon HW, Kim MJ, Ju YS. Widespread somatic L1 retrotransposition in normal colorectal epithelium. Nature 2023; 617:540-547. [PMID: 37165195 DOI: 10.1038/s41586-023-06046-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 04/04/2023] [Indexed: 05/12/2023]
Abstract
Throughout an individual's lifetime, genomic alterations accumulate in somatic cells1-11. However, the mutational landscape induced by retrotransposition of long interspersed nuclear element-1 (L1), a widespread mobile element in the human genome12-14, is poorly understood in normal cells. Here we explored the whole-genome sequences of 899 single-cell clones established from three different cell types collected from 28 individuals. We identified 1,708 somatic L1 retrotransposition events that were enriched in colorectal epithelium and showed a positive relationship with age. Fingerprinting of source elements showed 34 retrotransposition-competent L1s. Multidimensional analysis demonstrated that (1) somatic L1 retrotranspositions occur from early embryogenesis at a substantial rate, (2) epigenetic on/off of a source element is preferentially determined in the early organogenesis stage, (3) retrotransposition-competent L1s with a lower population allele frequency have higher retrotransposition activity and (4) only a small fraction of L1 transcripts in the cytoplasm are finally retrotransposed in somatic cells. Analysis of matched cancers further suggested that somatic L1 retrotransposition rate is substantially increased during colorectal tumourigenesis. In summary, this study illustrates L1 retrotransposition-induced somatic mosaicism in normal cells and provides insights into the genomic and epigenomic regulation of transposable elements over the human lifetime.
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Affiliation(s)
- Chang Hyun Nam
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Jeonghwan Youk
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
- Genome Insight, Inc., Daejeon, Republic of Korea
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | | | - Joonoh Lim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
- Genome Insight, Inc., Daejeon, Republic of Korea
| | - Jung Woo Park
- Korea Institute of Science and Technology Information, Daejeon, Republic of Korea
| | - Soo A Oh
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Hyun Jung Lee
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Ji Won Park
- Department of Surgery, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hyein Won
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Yunah Lee
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Seung-Yong Jeong
- Department of Surgery, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Dong-Sung Lee
- Department of Life Science, University of Seoul, Seoul, Republic of Korea
| | - Ji Won Oh
- Department of Anatomy, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Jinju Han
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Junehawk Lee
- Korea Institute of Science and Technology Information, Daejeon, Republic of Korea
| | - Hyun Woo Kwon
- Department of Nuclear Medicine, Korea University College of Medicine, Seoul, Republic of Korea.
| | - Min Jung Kim
- Department of Surgery, Seoul National University College of Medicine, Seoul, Republic of Korea.
| | - Young Seok Ju
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea.
- Genome Insight, Inc., Daejeon, Republic of Korea.
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21
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Ukadike KC, Najjar R, Ni K, Laine A, Wang X, Bays A, Taylor MS, LaCava J, Mustelin T. Expression of L1 retrotransposons in granulocytes from patients with active systemic lupus erythematosus. Mob DNA 2023; 14:5. [PMID: 37165451 PMCID: PMC10170740 DOI: 10.1186/s13100-023-00293-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 05/04/2023] [Indexed: 05/12/2023] Open
Abstract
BACKGROUND Patients with systemic lupus erythematosus (SLE) have autoantibodies against the L1-encoded open-reading frame 1 protein (ORF1p). Here, we report (i) which immune cells ORF1p emanates from, (ii) which L1 loci are transcriptionally active, (iii) whether the cells express L1-dependent interferon and interferon-stimulated genes, and (iv) the effect of inhibition of L1 ORF2p by reverse transcriptase inhibitors. RESULTS L1 ORF1p was detected by flow cytometry primarily in SLE CD66b+CD15+ regular and low-density granulocytes, but much less in other immune cell lineages. The amount of ORF1p was higher in neutrophils from patients with SLE disease activity index (SLEDAI) > 6 (p = 0.011) compared to patients with inactive disease, SLEDAI < 4. Patient neutrophils transcribed seven to twelve human-specific L1 loci (L1Hs), but only 3 that are full-length and with an intact ORF1. Besides serving as a source of detectable ORF1p, the most abundant transcript encoded a truncated ORF2p reverse transcriptase predicted to remain cytosolic, while the two other encoded an intact full-length ORF2p. A number of genes encoding proteins that influence L1 transcription positively or negatively were altered in patients, particularly those with active disease, compared to healthy controls. Components of nucleic acid sensing and interferon induction were also altered. SLE neutrophils also expressed type I interferon-inducible genes and interferon β, which were substantially reduced after treatment of the cells with drugs known to inhibit ORF2p reverse transcriptase activity. CONCLUSIONS We identified L1Hs loci that are transcriptionally active in SLE neutrophils, and a reduction in the epigenetic silencing mechanisms that normally counteract L1 transcription. SLE neutrophils contained L1-encoded ORF1p protein, as well as activation of the type I interferon system, which was inhibited by treatment with reverse transcriptase inhibitors. Our findings will enable a deeper analysis of L1 dysregulation and its potential role in SLE pathogenesis.
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Affiliation(s)
- Kennedy C Ukadike
- Department of Medicine, Division of Rheumatology, University of Washington, 750 Republican Street, Room E507, Seattle, WA, 99108, USA
- Department of Internal Medicine, Renown Rheumatology, Renown Health - University of Nevada, Reno School of Medicine, 75 Pringle Way, Suite 701, Reno, NV, 89502, USA
| | - Rayan Najjar
- Department of Medicine, Division of Rheumatology, University of Washington, 750 Republican Street, Room E507, Seattle, WA, 99108, USA
| | - Kathryn Ni
- Department of Medicine, Division of Rheumatology, University of Washington, 750 Republican Street, Room E507, Seattle, WA, 99108, USA
| | - Amanda Laine
- Department of Medicine, Division of Rheumatology, University of Washington, 750 Republican Street, Room E507, Seattle, WA, 99108, USA
| | - Xiaoxing Wang
- Department of Medicine, Division of Rheumatology, University of Washington, 750 Republican Street, Room E507, Seattle, WA, 99108, USA
| | - Alison Bays
- Department of Medicine, Division of Rheumatology, University of Washington, 750 Republican Street, Room E507, Seattle, WA, 99108, USA
| | - Martin S Taylor
- Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
| | - John LaCava
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, Groningen, The Netherlands
| | - Tomas Mustelin
- Department of Medicine, Division of Rheumatology, University of Washington, 750 Republican Street, Room E507, Seattle, WA, 99108, USA.
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22
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Demeneva VV, Tolmacheva EN, Nikitina TV, Sazhenova EA, Yuriev SY, Makhmutkhodzhaev AS, Zuev AS, Filatova SA, Dmitriev AE, Darkova YA, Nazarenko LP, Lebedev IN, Vasilyev SA. Expression of the NUP153 and YWHAB genes from their canonical promoters and alternative promoters of the LINE-1 retrotransposon in the placenta of the first trimester of pregnancy. Vavilovskii Zhurnal Genet Selektsii 2023; 27:63-71. [PMID: 36923475 PMCID: PMC10009475 DOI: 10.18699/vjgb-23-09] [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: 10/13/2022] [Revised: 12/26/2022] [Accepted: 12/30/2022] [Indexed: 03/11/2023] Open
Abstract
The placenta has a unique hypomethylated genome. Due to this feature of the placenta, there is a potential possibility of using regulatory elements derived from retroviruses and retrotransposons, which are suppressed by DNA methylation in the adult body. In addition, there is an abnormal increase in the level of methylation of the LINE-1 retrotransposon in the chorionic trophoblast in spontaneous abortions with both normal karyotype and aneuploidy on different chromosomes, which may be associated with impaired gene transcription using LINE-1 regulatory elements. To date, 988 genes that can be expressed from alternative LINE-1 promoters have been identified. Using the STRING tool, genes (NUP153 and YWHAB) were selected, the products of which have significant functional relationships with proteins highly expressed in the placenta and involved in trophoblast differentiation. This study aimed to analyze the expression of the NUP153 and YWHAB genes, highly active in the placenta, from canonical and alternative LINE-1 promoters in the germinal part of the placenta of spontaneous and induced abortions. Gene expression analysis was performed using real-time PCR in chorionic villi and extraembryonic mesoderm of induced abortions (n = 10), adult lymphocytes (n = 10), spontaneous abortions with normal karyotype (n = 10), and with the most frequent aneuploidies in the first trimester of pregnancy (trisomy 16 (n = 8) and monosomy X (n = 6)). The LINE-1 methylation index was assessed in the chorionic villi of spontaneous abortions using targeted bisulfite massive parallel sequencing. The level of expression of both genes from canonical promoters was higher in blood lymphocytes than in placental tissues (p < 0.05). However, the expression level of the NUP153 gene from the alternative LINE-1 promoter was 17 times higher in chorionic villi and 23 times higher in extraembryonic mesoderm than in lymphocytes (p < 0.05). The expression level of NUP153 and YWHAB from canonical promoters was higher in the group of spontaneous abortions with monosomy X compared to all other groups (p <0.05). The LINE-1 methylation index negatively correlated with the level of gene expression from both canonical (NUP153 - R = -0.59, YWHAB - R = -0.52, p < 0.05) and alternative LINE-1 promoters (NUP153 - R = -0.46, YWHAB - R = -0.66, p < 0.05). Thus, the observed increase in the LINE-1 methylation index in the placenta of spontaneous abortions is associated with the level of expression of the NUP153 and YWHAB genes not only from alternative but also from canonical promoters, which can subsequently lead to negative consequences for normal embryogenesis.
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Affiliation(s)
- V V Demeneva
- Research Institute of Medical Genetics, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk, Russia
| | - E N Tolmacheva
- Research Institute of Medical Genetics, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk, Russia
| | - T V Nikitina
- Research Institute of Medical Genetics, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk, Russia
| | - E A Sazhenova
- Research Institute of Medical Genetics, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk, Russia
| | - S Yu Yuriev
- Siberian State Medical University, Tomsk, Russia
| | | | - A S Zuev
- Research Institute of Medical Genetics, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk, Russia
| | - S A Filatova
- National Research Tomsk State University, Tomsk, Russia
| | - A E Dmitriev
- National Research Tomsk State University, Tomsk, Russia
| | - Ya A Darkova
- National Research Tomsk State University, Tomsk, Russia
| | - L P Nazarenko
- Research Institute of Medical Genetics, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk, Russia
| | - I N Lebedev
- Research Institute of Medical Genetics, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk, Russia Siberian State Medical University, Tomsk, Russia
| | - S A Vasilyev
- Research Institute of Medical Genetics, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk, Russia National Research Tomsk State University, Tomsk, Russia
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23
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Gasparotto E, Burattin FV, Di Gioia V, Panepuccia M, Ranzani V, Marasca F, Bodega B. Transposable Elements Co-Option in Genome Evolution and Gene Regulation. Int J Mol Sci 2023; 24:ijms24032610. [PMID: 36768929 PMCID: PMC9917352 DOI: 10.3390/ijms24032610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/26/2023] [Accepted: 01/28/2023] [Indexed: 01/31/2023] Open
Abstract
The genome is no longer deemed as a fixed and inert item but rather as a moldable matter that is continuously evolving and adapting. Within this frame, Transposable Elements (TEs), ubiquitous, mobile, repetitive elements, are considered an alive portion of the genomes to date, whose functions, although long considered "dark", are now coming to light. Here we will review that, besides the detrimental effects that TE mobilization can induce, TEs have shaped genomes in their current form, promoting genome sizing, genomic rearrangements and shuffling of DNA sequences. Although TEs are mostly represented in the genomes by evolutionarily old, short, degenerated, and sedentary fossils, they have been thoroughly co-opted by the hosts as a prolific and original source of regulatory instruments for the control of gene transcription and genome organization in the nuclear space. For these reasons, the deregulation of TE expression and/or activity is implicated in the onset and progression of several diseases. It is likely that we have just revealed the outermost layers of TE functions. Further studies on this portion of the genome are required to unlock novel regulatory functions that could also be exploited for diagnostic and therapeutic approaches.
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Affiliation(s)
- Erica Gasparotto
- Fondazione INGM, Istituto Nazionale di Genetica Molecolare “Enrica e Romeo Invernizzi”, 20122 Milan, Italy
- SEMM, European School of Molecular Medicine, 20139 Milan, Italy
| | - Filippo Vittorio Burattin
- Fondazione INGM, Istituto Nazionale di Genetica Molecolare “Enrica e Romeo Invernizzi”, 20122 Milan, Italy
- Department of Biosciences, University of Milan, 20133 Milan, Italy
| | - Valeria Di Gioia
- Fondazione INGM, Istituto Nazionale di Genetica Molecolare “Enrica e Romeo Invernizzi”, 20122 Milan, Italy
- SEMM, European School of Molecular Medicine, 20139 Milan, Italy
| | - Michele Panepuccia
- Fondazione INGM, Istituto Nazionale di Genetica Molecolare “Enrica e Romeo Invernizzi”, 20122 Milan, Italy
| | - Valeria Ranzani
- Fondazione INGM, Istituto Nazionale di Genetica Molecolare “Enrica e Romeo Invernizzi”, 20122 Milan, Italy
| | - Federica Marasca
- Fondazione INGM, Istituto Nazionale di Genetica Molecolare “Enrica e Romeo Invernizzi”, 20122 Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy
| | - Beatrice Bodega
- Fondazione INGM, Istituto Nazionale di Genetica Molecolare “Enrica e Romeo Invernizzi”, 20122 Milan, Italy
- Department of Biosciences, University of Milan, 20133 Milan, Italy
- Correspondence:
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24
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Sato S, Gillette M, de Santiago PR, Kuhn E, Burgess M, Doucette K, Feng Y, Mendez-Dorantes C, Ippoliti PJ, Hobday S, Mitchell MA, Doberstein K, Gysler SM, Hirsch MS, Schwartz L, Birrer MJ, Skates SJ, Burns KH, Carr SA, Drapkin R. LINE-1 ORF1p as a candidate biomarker in high grade serous ovarian carcinoma. Sci Rep 2023; 13:1537. [PMID: 36707610 PMCID: PMC9883229 DOI: 10.1038/s41598-023-28840-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 01/25/2023] [Indexed: 01/29/2023] Open
Abstract
Long interspersed element 1 (LINE-1) open reading frame 1 protein (ORF1p) expression is a common feature of many cancer types, including high-grade serous ovarian carcinoma (HGSOC). Here, we report that ORF1p is not only expressed but also released by ovarian cancer and primary tumor cells. Immuno-multiple reaction monitoring-mass spectrometry assays showed that released ORF1p is confidently detectable in conditioned media, ascites, and patients' plasma, implicating ORF1p as a potential biomarker. Interestingly, ORF1p expression is detectable in fallopian tube (FT) epithelial precursors of HGSOC but not in benign FT, suggesting that ORF1p expression in an early event in HGSOC development. Finally, treatment of FT cells with DNA methyltransferase inhibitors led to robust expression and release of ORF1p, validating the regulatory role of DNA methylation in LINE-1 repression in non-tumorigenic tissue.
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Affiliation(s)
- Sho Sato
- Penn Ovarian Cancer Research Center, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Michael Gillette
- The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, MA, 02114, USA.,Harvard Medical School, Boston, MA, 02115, USA
| | - Pamela R de Santiago
- Penn Ovarian Cancer Research Center, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Eric Kuhn
- The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Michael Burgess
- The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Kristen Doucette
- The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Yi Feng
- Penn Ovarian Cancer Research Center, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | | | - Paul J Ippoliti
- The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Sara Hobday
- Penn Ovarian Cancer Research Center, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Marilyn A Mitchell
- Penn Ovarian Cancer Research Center, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Kai Doberstein
- Penn Ovarian Cancer Research Center, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Stefan M Gysler
- Penn Ovarian Cancer Research Center, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Michelle S Hirsch
- Department of Pathology, Brigham and Women's Hospital, Boston, MA, 02115, USA.,Harvard Medical School, Boston, MA, 02115, USA
| | - Lauren Schwartz
- Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Michael J Birrer
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35233, USA
| | - Steven J Skates
- Harvard Medical School, Boston, MA, 02115, USA.,Biostatistics and Computational Biology, Massachusetts General Hospital, Boston, MA, USA
| | - Kathleen H Burns
- Harvard Medical School, Boston, MA, 02115, USA.,Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Steven A Carr
- The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Harvard Medical School, Boston, MA, 02115, USA
| | - Ronny Drapkin
- Penn Ovarian Cancer Research Center, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA. .,Basser Center for BRCA, Abramson Cancer Center, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, 19104, USA.
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25
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Luca CD, Gupta A, Bortvin A. Ribonucleoprotein condensation driven by retrotransposon LINE-1 sustains RNA integrity and translation in mouse spermatocytes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.09.523313. [PMID: 36712121 PMCID: PMC9882024 DOI: 10.1101/2023.01.09.523313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Transposable elements (TE) are mobile DNA sequences whose excessive proliferation endangers the host. Although animals have evolved robust TE-targeting defenses, including Piwi-interacting (pi)RNAs, retrotransposon LINE-1 (L1) still thrives in humans and mice. To gain insights into L1 endurance, we characterized L1 Bodies (LBs) and ORF1p complexes in germ cells of piRNA-deficient Maelstrom null mice. We report that ORF1p interacts with TE RNAs, genic mRNAs, and stress granule proteins, consistent with earlier studies. We also show that ORF1p associates with the CCR4-NOT deadenylation complex and PRKRA, a Protein Kinase R factor. Despite ORF1p interactions with these negative regulators of RNA expression, the stability and translation of LB-localized mRNAs remain unchanged. To scrutinize these findings, we studied the effects of PRKRA on L1 in cultured cells and showed that it elevates ORF1p levels and L1 retrotransposition. These results suggest that ORF1p-driven condensates promote L1 propagation, without affecting the metabolism of endogenous RNAs.
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26
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Hejníčková M, Dalíková M, Zrzavá M, Marec F, Lorite P, Montiel EE. Accumulation of retrotransposons contributes to W chromosome differentiation in the willow beauty Peribatodes rhomboidaria (Lepidoptera: Geometridae). Sci Rep 2023; 13:534. [PMID: 36631492 PMCID: PMC9834309 DOI: 10.1038/s41598-023-27757-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 01/06/2023] [Indexed: 01/12/2023] Open
Abstract
The W chromosome of Lepidoptera is typically gene-poor, repeat-rich and composed of heterochromatin. Pioneering studies investigating this chromosome reported an abundance of mobile elements. However, the actual composition of the W chromosome varies greatly between species, as repeatedly demonstrated by comparative genomic hybridization (CGH) or fluorescence in situ hybridization (FISH). Here we present an analysis of repeats on the W chromosome in the willow beauty, Peribatodes rhomboidaria (Geometridae), a species in which CGH predicted an abundance of W-enriched or W-specific sequences. Indeed, comparative analysis of male and female genomes using RepeatExplorer identified ten putative W chromosome-enriched repeats, most of which are LTR or LINE mobile elements. We analysed the two most abundant: PRW LINE-like and PRW Bel-Pao. The results of FISH mapping and bioinformatic analysis confirmed their enrichment on the W chromosome, supporting the hypothesis that mobile elements are the driving force of W chromosome differentiation in Lepidoptera. As the W chromosome is highly underrepresented in chromosome-level genome assemblies of Lepidoptera, this recently introduced approach, combining bioinformatic comparative genome analysis with molecular cytogenetics, provides an elegant tool for studying this elusive and rapidly evolving part of the genome.
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Affiliation(s)
- Martina Hejníčková
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic.
| | - Martina Dalíková
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Magda Zrzavá
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic
| | - František Marec
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic
| | - Pedro Lorite
- Department of Experimental Biology, Genetics Area, University of Jaén, Jaén, Spain
| | - Eugenia E Montiel
- Department of Experimental Biology, Genetics Area, University of Jaén, Jaén, Spain
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27
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Garcia-Cañadas M, Sanchez-Luque FJ, Sanchez L, Rojas J, Garcia Perez JL. LINE-1 Retrotransposition Assays in Embryonic Stem Cells. Methods Mol Biol 2023; 2607:257-309. [PMID: 36449167 DOI: 10.1007/978-1-0716-2883-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The ongoing mobilization of active non-long terminal repeat (LTR) retrotransposons continues to impact the genomes of most mammals, including humans and rodents. Non-LTR retrotransposons mobilize using an intermediary RNA and a copy-and-paste mechanism termed retrotransposition. Non-LTR retrotransposons are subdivided into long and short interspersed elements (LINEs and SINEs, respectively), depending on their size and autonomy; while active class 1 LINEs (LINE-1s or L1s) encode the enzymatic machinery required to mobilize in cis, active SINEs use the enzymatic machinery of active LINE-1s to mobilize in trans. The mobilization mechanism used by LINE-1s/SINEs was exploited to develop ingenious plasmid-based retrotransposition assays in cultured cells, which typically exploit a reporter gene that can only be activated after a round of retrotransposition. Retrotransposition assays, in cis or in trans, are instrumental tools to study the biology of mammalian LINE-1s and SINEs. In fact, these and other biochemical/genetic assays were used to uncover that endogenous mammalian LINE-1s/SINEs naturally retrotranspose during early embryonic development. However, embryonic stem cells (ESCs) are typically used as a cellular model in these and other studies interrogating LINE-1/SINE expression/regulation during early embryogenesis. Thus, human and mouse ESCs represent an excellent model to understand how active retrotransposons are regulated and how their activity impacts the germline. Here, we describe robust and quantitative protocols to study human/mouse LINE-1 (in cis) and SINE (in trans) retrotransposition using (human and mice) ESCs. These protocols are designed to study the mobilization of active non-LTR retrotransposons in a cellular physiologically relevant context.
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Affiliation(s)
- Marta Garcia-Cañadas
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain.
| | - Francisco J Sanchez-Luque
- Institute of Parasitology and Biomedicine "Lopez-Neyra" (IPBLN), Spanish National Research Council (CSIC), PTS Granada, Granada, Spain
| | - Laura Sanchez
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain
| | - Johana Rojas
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain
| | - Jose L Garcia Perez
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain.
- MRC Human Genetics Unit, Institute of Genetics and Cancer (IGC)/University of Edinburgh, Western General Hospital Campus, Edinburgh, UK.
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28
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Di Stefano LH, Saba LJ, Oghbaie M, Jiang H, McKerrow W, Benitez-Guijarro M, Taylor MS, LaCava J. Affinity-Based Interactome Analysis of Endogenous LINE-1 Macromolecules. Methods Mol Biol 2023; 2607:215-256. [PMID: 36449166 DOI: 10.1007/978-1-0716-2883-6_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
During their proliferation and the host's concomitant attempts to suppress it, LINE-1 (L1) retrotransposons give rise to a collection of heterogeneous ribonucleoproteins (RNPs); their protein and RNA compositions remain poorly defined. The constituents of L1-associated macromolecules can differ depending on numerous factors, including, for example, position within the L1 life cycle, whether the macromolecule is productive or under suppression, and the cell type within which the proliferation is occurring. This chapter describes techniques that aid the capture and characterization of protein and RNA components of L1 macromolecules from tissues that natively express them. The protocols described have been applied to embryonal carcinoma cell lines that are popular model systems for L1 molecular biology (e.g., N2102Ep, NTERA-2, and PA-1 cells), as well as colorectal cancer tissues. N2102Ep cells are given as the use case for this chapter; the protocols should be applicable to essentially any tissue exhibiting endogenous L1 expression with minor modifications.
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29
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George S, Cassidy RN, Saintilnord WN, Fondufe-Mittendorf Y. Epigenomic reprogramming in iAs-mediated carcinogenesis. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2022; 96:319-365. [PMID: 36858778 DOI: 10.1016/bs.apha.2022.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Arsenic is a naturally occurring metal carcinogen found in the Earth's crust. Millions of people worldwide are chronically exposed to arsenic through drinking water and food. Exposure to inorganic arsenic has been implicated in many diseases ranging from acute toxicities to malignant transformations. Despite the well-known deleterious health effects of arsenic exposure, the molecular mechanisms in arsenic-mediated carcinogenesis are not fully understood. Since arsenic is non-mutagenic, the mechanism by which arsenic causes carcinogenesis is via alterations in epigenetic-regulated gene expression. There are two possible ways by which arsenic may modify the epigenome-indirectly through an arsenic-induced generation of reactive oxygen species which then impacts chromatin remodelers, or directly through interaction and modulation of chromatin remodelers. Whether directly or indirectly, arsenic modulates epigenetic gene regulation and our understanding of the direct effect of this modulation on chromatin structure is limited. In this chapter we will discuss the various ways by which inorganic arsenic affects the epigenome with consequences in health and disease.
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Affiliation(s)
- Smitha George
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, United States
| | - Richard N Cassidy
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, United States
| | - Wesley N Saintilnord
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, United States; Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, United States
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30
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Nef Suppresses LINE-1 Retrotransposition through Two Distinct Mechanisms. J Virol 2022; 96:e0114822. [PMID: 36197106 DOI: 10.1128/jvi.01148-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Long interspersed element type 1 (LINE-1) is the only known type of retroelement that can replicate autonomously, and its retrotransposition activity can trigger interferon (IFN) production. IFN production suppresses the infectivity of exogenous viruses, such as human immunodeficiency virus (HIV). As a counteraction, HIV has been reported to use multiple proteins and mechanisms to suppress LINE-1 replication. However, the mechanisms of HIV-mediated LINE-1 regulation are not fully understood. In this study, we discovered that Nef protein, which is expressed by HIV and is important for HIV pathogenesis, inhibits LINE-1 retrotransposition. Two distinct mechanisms have been uncovered for Nef-induced LINE-1 suppression. Without direct interaction with LINE-1 DNA, Nef potently inhibits the promoter activity of the LINE-1 5'-untranslated region (5'-UTR) and reduces the expression levels of LINE-1 RNA and proteins. Alternatively, although Nef does not bind to the LINE-1 open reading frame 1 protein (ORF1p) or LINE-1 RNA, it significantly compromises the ORF1p-LINE-1 RNA interaction, which is essential for LINE-1 retrotransposition. Both mechanisms can be suppressed by the G2A mutation, which abolishes myristoylation of Nef, suggesting that membrane attachment is essential for Nef to suppress LINE-1. Consequently, through LINE-1 inhibition, Nef downregulates IFN production in host cells. Therefore, our data revealed that Nef is a potent LINE-1 suppressor and an effective innate immune regulator, which not only provides new information on the intricate interaction between HIV, LINE-1, and IFN signaling systems but also strengthens the importance of Nef in HIV infection and highlights the potential of designing novel Nef-targeting anti-HIV drugs. IMPORTANCE Human immunodeficiency viruses are pathogens of AIDS that were first discovered almost 40 years ago and continue to threaten human lives to date. While currently used anti-HIV drugs are sufficient to suppress viral loads in HIV-infected patients, both drug-resistant HIV strains and adverse side effects triggered by the long-term use of these drugs highlight the need to develop novel anti-HIV drugs targeting different viral proteins and/or different steps in viral replication. To achieve this, more information is required regarding HIV pathogenesis and especially its impact on cellular activities in host cells. In this study, we discovered that the Nef protein expressed by HIV potently inhibits LINE-1 retrotransposition. During our attempt to determine the mechanism of Nef-mediated LINE-1 suppression, two additional functions of Nef were uncovered. Nef effectively repressed the promoter activity of LINE-1 5'-UTR and destabilized the interaction between ORF1p and LINE-1 RNA. Consequently, Nef not only compromises LINE-1 replication but also reduces LINE-1-triggered IFN production. The reduction in IFN production, in theory, promotes HIV infectivity. Together with its previously known functions, these findings indicate that Nef is a potential target for the development of novel anti-HIV drugs. Notably, the G2 residue, which has been reported to be essential for most Nef functions, was found to be critical in the regulation of innate immune activation by Nef, suggesting that compromising myristoylation or membrane attachment of Nef may be a good strategy for the inhibition of HIV infection.
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31
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Hepatitis B virus polymerase restricts LINE-1 mobility. Gene 2022; 850:146943. [PMID: 36198378 DOI: 10.1016/j.gene.2022.146943] [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: 05/23/2022] [Revised: 09/06/2022] [Accepted: 09/28/2022] [Indexed: 11/21/2022]
Abstract
Long interspersed element-1 (LINE-1, L1) transposable element (TE) composes about 17% of the human genome. However, genetic and biochemical interactions between L1 and hepatitis B virus (HBV) remain poorly understood. In this study, I found that HBV restricts L1 retrotransposition in a reverse transcriptase (RT)-independent manner. Notably, HBV polymerase (Pol) strongly inhibited L1 retrotransposition. Indeed, the ribonuclease H (RNase H) domain was essential for inhibition of L1 retrotransposition. The L1 ORF1p RNA-binding protein predominantly localized into cytoplasmic RNA granule termed P-body. However, HBV Pol hijacked L1 ORF1p from P-body through an interaction with L1 ORF1p, when both proteins were co-expressed. Furthermore, HBV Pol repressed the L1 5' untranslated region (UTR). Altogether, HBV seems to restrict L1 mobility at multiple steps. Thus, these results suggest a novel function or activity of HBV Pol in regulation of L1 retrotransposition.
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32
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Zhao Y, Zhao K, Wang S, Du J. Multi-functional BST2/tetherin against HIV-1, other viruses and LINE-1. Front Cell Infect Microbiol 2022; 12:979091. [PMID: 36176574 PMCID: PMC9513188 DOI: 10.3389/fcimb.2022.979091] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 08/25/2022] [Indexed: 11/13/2022] Open
Abstract
Bone marrow stromal cell antigen 2 (BST2), also known as CD317, HM1.24, or tetherin, is a type II transmembrane glycoprotein. Its expression is induced by IFN-I, and it initiates host immune responses by directly trapping enveloped HIV-1 particles onto the cell surface. This antagonistic mechanism toward the virus is attributable to the unique structure of BST2. In addition to its antiviral activity, BST2 restricts retrotransposon LINE-1 through a distinct mechanism. As counteractive measures, different viruses use a variety of proteins to neutralize the function or even stability of BST2. Interestingly, BST2 seems to have both a positive and a negative influence on immunomodulation and virus propagation. Here, we review the relationship between the structural and functional bases of BST2 in anti-HIV-1 and suppressing retrotransposon LINE-1 activation and focus on its dual features in immunomodulation and regulating virus propagation.
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Affiliation(s)
- Yifei Zhao
- Center of Infectious Diseases and Pathogen Biology, The First Hospital of Jilin University, Changchun, China
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China
| | - Ke Zhao
- Center of Infectious Diseases and Pathogen Biology, The First Hospital of Jilin University, Changchun, China
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China
| | - Shaohua Wang
- Center of Infectious Diseases and Pathogen Biology, The First Hospital of Jilin University, Changchun, China
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China
| | - Juan Du
- Center of Infectious Diseases and Pathogen Biology, The First Hospital of Jilin University, Changchun, China
- Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, China
- *Correspondence: Juan Du,
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Osburn SC, Mesquita P, Neal FK, Rumbley M, Holmes MT, Ruple BA, Mobley CB, Brown MD, McCullough DJ, Kavazis AN, Roberts MD. Long-term voluntary wheel running effects on markers of Long Interspersed Nuclear Element-1 in skeletal muscle, liver, and brain tissue of female rats. Am J Physiol Cell Physiol 2022; 323:C907-C919. [PMID: 35938680 DOI: 10.1152/ajpcell.00234.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We sought to determine the effects of long-term voluntary wheel running on markers of Long Interspersed Nuclear Element-1 (L1) in skeletal muscle, liver, and the hippocampus of female rats. Additionally, markers of the cGAS-STING DNA sensing pathway that results in inflammation were interrogated. Female Lewis rats (n=34) were separated into one of three groups including a 6-month-old group to serve as a young comparator group (CTL, n=10), a group that had access to a running wheel for voluntary wheel running (EX, n=12), and an age-matched group that did not (SED, n=12). Both SED and EX groups were carried out from 6 months to 15 months of age. There were no significant differences in L1 mRNA expression for any of the tissues between groups. Methylation of the L1 promoter in the soleus and hippocampus was significantly higher in SED and EX compared to CTL (p<0.05). ORF1p expression was higher in older SED and EX rats compared to CTL for every tissue (p<0.05). There were no differences between groups for L1 mRNA or cGAS-STING pathway markers. Our results suggest there is an increased ORF1 protein expression across tissues with aging that is not mitigated by voluntary wheel running. Additionally, while previous data imply that L1 methylation changes may play a role in acute exercise for L1 RNA expression, this does not seem to occur during extended periods of voluntary wheel running.
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Affiliation(s)
- Shelby C Osburn
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Paulo Mesquita
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Frances K Neal
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Melissa Rumbley
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Matthew T Holmes
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Bradley A Ruple
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - C Brooks Mobley
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Michael D Brown
- School of Public Health, University of Maryland, College Park, MD, United States
| | - Danielle J McCullough
- School of Kinesiology, Auburn University, Auburn, AL, United States.,Edward Via College of Osteopathic Medicine, Auburn, AL, United States
| | | | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, AL, United States.,Edward Via College of Osteopathic Medicine, Auburn, AL, United States
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Lee Y, Ha U, Moon S. Ongoing endeavors to detect mobilization of transposable elements. BMB Rep 2022. [PMID: 35725016 PMCID: PMC9340088 DOI: 10.5483/bmbrep.2022.55.7.088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transposable elements (TEs) are DNA sequences capable of mobilization from one location to another in the genome. Since the discovery of ‘Dissociation (Dc) locus’ by Barbara McClintock in maize (1), mounting evidence in the era of genomics indicates that a significant fraction of most eukaryotic genomes is composed of TE sequences, involving in various aspects of biological processes such as development, physiology, diseases and evolution. Although technical advances in genomics have discovered numerous functional impacts of TE across species, our understanding of TEs is still ongoing process due to challenges resulted from complexity and abundance of TEs in the genome. In this mini-review, we briefly summarize biology of TEs and their impacts on the host genome, emphasizing importance of understanding TE landscape in the genome. Then, we introduce recent endeavors especially in vivo retrotransposition assays and long read sequencing technology for identifying de novo insertions/TE polymorphism, which will broaden our knowledge of extraordinary relationship between genomic cohabitants and their host.
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Affiliation(s)
- Yujeong Lee
- Department of Biological Sciences, Kangwon National University, Chuncheon 24341, Korea
| | - Una Ha
- Department of Biological Sciences, Kangwon National University, Chuncheon 24341, Korea
| | - Sungjin Moon
- Department of Biological Sciences, Kangwon National University, Chuncheon 24341, Korea
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Kabi M, Filion GJ. Chromatin and viral integration in immunity: The challenge of silencing non-self genes. Trends Immunol 2022; 43:449-458. [PMID: 35490134 DOI: 10.1016/j.it.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/03/2022] [Accepted: 04/04/2022] [Indexed: 11/24/2022]
Abstract
Several viruses hide in the genome of their host. To complete their replication cycle, they need to integrate in the form of a provirus and express their genes. In vertebrates, integrated viruses can be silenced by chromatin, implying that some specific mechanisms exist to detect non-self genes. The known mechanisms depend on sequence features of retroelements, but the fluctuations of virus expression suggest that other determinants also exist. Here we review the mechanisms allowing chromatin to silence integrated viruses and propose that DNA repair may help flag them as 'non-self' shortly after their genomic insertion.
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Affiliation(s)
- Manisha Kabi
- Department of Biological Sciences, University of Toronto Scarborough, Scarborough, ON, Canada
| | - Guillaume J Filion
- Department of Biological Sciences, University of Toronto Scarborough, Scarborough, ON, Canada.
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Wang Q, Du J, Hua S, Zhao K. TREX1 Plays Multiple Roles in Human Diseases. Cell Immunol 2022; 375:104527. [DOI: 10.1016/j.cellimm.2022.104527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 03/12/2022] [Accepted: 04/10/2022] [Indexed: 11/15/2022]
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Pinter TB, Ervin CS, Deb A, Penner-Hahn JE, Pecoraro VL. Cu(I) Binding to Designed Proteins Reveals a Putative Copper Binding Site of the Human Line1 Retrotransposon Protein ORF1p. Inorg Chem 2022; 61:5084-5091. [PMID: 35286080 PMCID: PMC10754372 DOI: 10.1021/acs.inorgchem.2c00057] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Long interspersed nuclear elements-1 (L1) are autonomous retrotransposons that encode two proteins in different open reading frames (ORF1 and ORF2). The ORF1p, which may be an RNA binding and chaperone protein, contains a three-stranded coiled coil (3SCC) domain that facilitates the formation of the biologically active homotrimer. This 3SCC domain is composed of seven amino acid (heptad) repeats as found in native and designed peptides and a stammer that modifies the helical structure. Cysteine residues occur at three hydrophobic positions (2 a and 1 d sites) within this domain. We recently showed that the cysteine layers in ORF1p and model de novo designed peptides bind the toxic metalloid lead(II) with high affinities, a feature that had not been previously recognized. However, there is little understanding of how essential metal ions might interact with this metal binding domain. We have, therefore, investigated the copper(I) binding properties of analogous de novo designed 3SCCs that contain cysteine layers within the hydrophobic core. The results from UV-visible and X-ray absorption spectroscopy show that these designed peptides bind Cu(I) with high affinity in a pH-dependent manner. At pH 9, monomeric trigonal planar Cu(I)S3 centers are formed with 1 equiv of metal, while dinuclear centers form with a second equivalent of metal. At physiologic pH conditions, the dinuclear center forms cooperatively. These data suggest that ORF1p is capable of binding two copper ions to its tris(cysteine) layers. This has major implications for ORF1p coiled coil domain stability and dynamics, ultimately potentially impacting the resulting biological activity.
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Affiliation(s)
- Tyler B.J. Pinter
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- These authors contributed equally to this work
| | - Catherine S. Ervin
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- These authors contributed equally to this work
| | - Aniruddha Deb
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Program in Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - James E. Penner-Hahn
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Program in Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Vincent L. Pecoraro
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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Garland W, Müller I, Wu M, Schmid M, Imamura K, Rib L, Sandelin A, Helin K, Jensen TH. Chromatin modifier HUSH co-operates with RNA decay factor NEXT to restrict transposable element expression. Mol Cell 2022; 82:1691-1707.e8. [PMID: 35349793 PMCID: PMC9433625 DOI: 10.1016/j.molcel.2022.03.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 12/14/2021] [Accepted: 03/01/2022] [Indexed: 12/12/2022]
Abstract
Transposable elements (TEs) are widespread genetic parasites known to be kept under tight transcriptional control. Here, we describe a functional connection between the mouse-orthologous “nuclear exosome targeting” (NEXT) and “human silencing hub” (HUSH) complexes, involved in nuclear RNA decay and the epigenetic silencing of TEs, respectively. Knocking out the NEXT component ZCCHC8 in embryonic stem cells results in elevated TE RNA levels. We identify a physical interaction between ZCCHC8 and the MPP8 protein of HUSH and establish that HUSH recruits NEXT to chromatin at MPP8-bound TE loci. However, while NEXT and HUSH both dampen TE RNA expression, their activities predominantly affect shorter non-polyadenylated and full-length polyadenylated transcripts, respectively. Indeed, our data suggest that the repressive action of HUSH promotes a condition favoring NEXT RNA decay activity. In this way, transcriptional and post-transcriptional machineries synergize to suppress the genotoxic potential of TE RNAs. Garland et al. report a physical and functional connection between the NEXT complex, involved in RNA decay, and the HUSH complex, involved in chromatin regulation. Together, NEXT and HUSH cooperate to control transposable element (TE) RNA expression in embryonic stem cells, suppressing pA− and pA+ transcripts, respectively.
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Affiliation(s)
- William Garland
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark; Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Iris Müller
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation for Stem Cell Biology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark; Cell Biology Program and Center for Epigenetics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Mengjun Wu
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Bioinformatics Centre, Department of Biology, University of Copenhagen, Copenhagen, Denmark; SciLifeLab, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Manfred Schmid
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Katsutoshi Imamura
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Leonor Rib
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Bioinformatics Centre, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Albin Sandelin
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Bioinformatics Centre, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kristian Helin
- Biotech Research and Innovation Centre (BRIC), Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation for Stem Cell Biology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark; Cell Biology Program and Center for Epigenetics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
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Freeman B, White T, Kaul T, Stow EC, Baddoo M, Ungerleider N, Morales M, Yang H, Deharo D, Deininger P, Belancio V. Analysis of epigenetic features characteristic of L1 loci expressed in human cells. Nucleic Acids Res 2022; 50:1888-1907. [PMID: 35100410 PMCID: PMC8887483 DOI: 10.1093/nar/gkac013] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 12/27/2021] [Accepted: 01/24/2022] [Indexed: 12/26/2022] Open
Abstract
Only a select few L1 loci in the human genome are expressed in any given cell line or organ, likely to minimize damage done to the genome. The epigenetic features and requirements of expressed L1 loci are currently unknown. Using human cells and comprehensive epigenetic analysis of individual expressed and unexpressed L1 loci, we determined that endogenous L1 transcription depends on a combination of epigenetic factors, including open chromatin, activating histone modifications, and hypomethylation at the L1 promoter. We demonstrate that the L1 promoter seems to require interaction with enhancer elements for optimal function. We utilize epigenetic context to predict the expression status of L1Hs loci that are poorly mappable with RNA-Seq. Our analysis identified a population of ‘transitional’ L1 loci that likely have greater potential to be activated during the epigenetic dysregulation seen in tumors and during aging because they are the most responsive to targeted CRISPR-mediated delivery of trans-activating domains. We demonstrate that an engineered increase in endogenous L1 mRNA expression increases Alu mobilization. Overall, our findings present the first global and comprehensive analysis of epigenetic status of individual L1 loci based on their expression status and demonstrate the importance of epigenetic context for L1 expression heterogeneity.
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Affiliation(s)
- Benjamin Freeman
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
| | - Travis White
- Sloan Kettering Institute for Cancer Research, NY, NY 10065, USA
| | - Tiffany Kaul
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
| | - Emily C Stow
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
| | - Melody Baddoo
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, USA
| | - Nathan Ungerleider
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, USA
| | - Maria Morales
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
| | - Hanlin Yang
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
| | - Dawn Deharo
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112, USA
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
| | - Prescott Deininger
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
- Department of Epidemiology, Tulane School of Public Health and Tropical Medicine, New Orleans, LA 70112, USA
| | - Victoria P Belancio
- To whom correspondence should be addressed. Tel: +1 504 988 4506; Fax: +1 504 988 1687;
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Floreani L, Ansaloni F, Mangoni D, Agostoni E, Sanges R, Persichetti F, Gustincich S. Analysis of LINE1 Retrotransposons in Huntington’s Disease. Front Cell Neurosci 2022; 15:743797. [PMID: 35095420 PMCID: PMC8795916 DOI: 10.3389/fncel.2021.743797] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 12/27/2021] [Indexed: 12/27/2022] Open
Abstract
Transposable elements (TEs) are mobile genetic elements that made up about half the human genome. Among them, the autonomous non-LTR retrotransposon long interspersed nuclear element-1 (L1) is the only currently active TE in mammals and covers about 17% of the mammalian genome. L1s exert their function as structural elements in the genome, as transcribed RNAs to influence chromatin structure and as retrotransposed elements to shape genomic variation in somatic cells. L1s activity has been shown altered in several diseases of the nervous system. Huntington disease (HD) is a dominantly inherited neurodegenerative disorder caused by an expansion of a CAG repeat in the HTT gene which leads to a gradual loss of neurons most prominently in the striatum and, to a lesser extent, in cortical brain regions. The length of the expanded CAG tract is related to age at disease onset, with longer repeats leading to earlier onset. Here we carried out bioinformatic analysis of public RNA-seq data of a panel of HD mouse models showing that a decrease of L1 RNA expression recapitulates two hallmarks of the disease: it correlates to CAG repeat length and it occurs in the striatum, the site of neurodegeneration. Results were then experimentally validated in HttQ111 knock-in mice. The expression of L1-encoded proteins was independent from L1 RNA levels and differentially regulated in time and tissues. The pattern of expression L1 RNAs in human HD post-mortem brains showed similarity to mouse models of the disease. This work suggests the need for further study of L1s in HD and adds support to the current hypothesis that dysregulation of TEs may be involved in neurodegenerative diseases.
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Affiliation(s)
- Lavinia Floreani
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Federico Ansaloni
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia—IIT, Genova, Italy
| | - Damiano Mangoni
- Central RNA Laboratory, Istituto Italiano di Tecnologia—IIT, Genova, Italy
| | - Elena Agostoni
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Remo Sanges
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia—IIT, Genova, Italy
- *Correspondence: Remo Sanges,
| | - Francesca Persichetti
- Department of Health Sciences, University of Piemonte Orientale “ A. Avogadro,”Novara, Italy
- Francesca Persichetti,
| | - Stefano Gustincich
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia—IIT, Genova, Italy
- Stefano Gustincich,
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Kaur D, Agrahari M, Bhattacharya A, Bhattacharya S. The non-LTR retrotransposons of Entamoeba histolytica: genomic organization and biology. Mol Genet Genomics 2022; 297:1-18. [PMID: 34999963 DOI: 10.1007/s00438-021-01843-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 11/26/2021] [Indexed: 11/24/2022]
Abstract
Genome sequence analysis of Entamoeba species revealed various classes of transposable elements. While E. histolytica and E. dispar are rich in non-long terminal repeat (LTR) retrotransposons, E. invadens contains predominantly DNA transposons. Non-LTR retrotransposons of E. histolytica constitute three families of long interspersed nuclear elements (LINEs), and their short, nonautonomous partners, SINEs. They occupy ~ 11% of the genome. The EhLINE1/EhSINE1 family is the most abundant and best studied. EhLINE1 is 4.8 kb, with two ORFs that encode functions needed for retrotransposition. ORF1 codes for the nucleic acid-binding protein, and ORF2 has domains for reverse transcriptase (RT) and endonuclease (EN). Most copies of EhLINEs lack complete ORFs. ORF1p is expressed constitutively, but ORF2p is not detected. Retrotransposition could be demonstrated upon ectopic over expression of ORF2p, showing that retrotransposition machinery is functional. The newly retrotransposed sequences showed a high degree of recombination. In transcriptomic analysis, RNA-Seq reads were mapped to individual EhLINE1 copies. Although full-length copies were transcribed, no full-length 4.8 kb transcripts were seen. Rather, sense transcripts mapped to ORF1, RT and EN domains. Intriguingly, there was strong antisense transcription almost exclusively from the RT domain. These unique features of EhLINE1 could serve to attenuate retrotransposition in E. histolytica.
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Rajabi F, Jabalameli N, Rezaei N. The Concept of Immunogenetics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1367:1-17. [DOI: 10.1007/978-3-030-92616-8_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wang F, Chamani IJ, Luo D, Chan K, Navarro PA, Keefe DL. Inhibition of LINE-1 retrotransposition represses telomere reprogramming during mouse 2-cell embryo development. J Assist Reprod Genet 2021; 38:3145-3153. [PMID: 34618297 DOI: 10.1007/s10815-021-02331-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 09/23/2021] [Indexed: 12/22/2022] Open
Abstract
PURPOSE To investigate whether inhibition of LINE-1 affects telomere reprogramming during 2-cell embryo development. METHODS Mouse zygotes were cultured with or without 1 µM azidothymidine (AZT) for up to 15 h (early 2-cell, G1/S) or 24 h (late 2-cell, S/G2). Gene expression and DNA copy number were determined by RT-qPCR and qPCR respectively. Immunostaining and telomeric PNA-FISH were performed for co-localization between telomeres and ZSCAN4 or LINE-1-Orf1p. RESULTS LINE-1 copy number was remarkably reduced in later 2-cell embryos by exposure to 1 µM AZT, and telomere lengths in late 2-cell embryos with AZT were significantly shorter compared to control embryos (P = 0.0002). Additionally, in the absence of LINE-1 inhibition, Dux, Zscan4, and LINE-1 were highly transcribed in early 2-cell embryos, as compared to late 2-cell embryos (P < 0.0001), suggesting that these 2-cell genes are activated at the early 2-cell stage. However, in early 2-cell embryos with AZT treatment, mRNA levels of Dux, Zscan4, and LINE-1 were significantly decreased. Furthermore, both Zscan4 and LINE-1 encoded proteins localized to telomere regions in 2-cell embryos, but this co-localization was dramatically reduced after AZT treatment (P < 0.001). CONCLUSIONS Upon inhibition of LINE-1 retrotransposition in mouse 2-cell embryos, Dux, Zscan4, and LINE-1 were significantly downregulated, and telomere elongation was blocked. ZSCAN4 foci and their co-localization with telomeres were also significantly decreased, indicating that ZSCAN4 is an essential component of the telomere reprogramming that occurs in mice at the 2-cell stage. Our findings also suggest that LINE-1 may directly contribute to telomere reprogramming in addition to regulating gene expression.
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Affiliation(s)
- Fang Wang
- Department of Obstetrics and Gynecology, New York University Grossman School of Medicine, New York, NY, 10016, USA.
| | - Isaac J Chamani
- Department of Obstetrics and Gynecology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Danxia Luo
- Department of Obstetrics and Gynecology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Kasey Chan
- Department of Obstetrics and Gynecology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Paula Andrea Navarro
- Human Reproduction Division, Department of Gynecology and Obstetrics, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirão Preto, Brazil
| | - David L Keefe
- Department of Obstetrics and Gynecology, New York University Grossman School of Medicine, New York, NY, 10016, USA
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Ramos KS, Bojang P, Bowers E. Role of long interspersed nuclear element-1 in the regulation of chromatin landscapes and genome dynamics. Exp Biol Med (Maywood) 2021; 246:2082-2097. [PMID: 34304633 PMCID: PMC8524765 DOI: 10.1177/15353702211031247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 06/22/2021] [Indexed: 12/27/2022] Open
Abstract
LINE-1 retrotransposon, the most active mobile element of the human genome, is subject to tight regulatory control. Stressful environments and disease modify the recruitment of regulatory proteins leading to unregulated activation of LINE-1. The activation of LINE-1 influences genome dynamics through altered chromatin landscapes, insertion mutations, deletions, and modulation of cellular plasticity. To date, LINE-1 retrotransposition has been linked to various cancer types and may in fact underwrite the genetic basis of various other forms of chronic human illness. The occurrence of LINE-1 polymorphisms in the human population may define inter-individual differences in susceptibility to disease. This review is written in honor of Dr Peter Stambrook, a friend and colleague who carried out highly impactful cancer research over many years of professional practice. Dr Stambrook devoted considerable energy to helping others live up to their full potential and to navigate the complexities of professional life. He was an inspirational leader, a strong advocate, a kind mentor, a vocal supporter and cheerleader, and yes, a hard critic and tough friend when needed. His passionate stand on issues, his witty sense of humor, and his love for humanity have left a huge mark in our lives. We hope that that the knowledge summarized here will advance our understanding of the role of LINE-1 in cancer biology and expedite the development of innovative cancer diagnostics and treatments in the ways that Dr Stambrook himself had so passionately envisioned.
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Affiliation(s)
- Kenneth S Ramos
- Institute of Biosciences and Technology, Texas A&M Health, Houston, TX 77030, USA
| | - Pasano Bojang
- University of Kentucky College of Medicine, Lexington, KY 40506, USA
| | - Emma Bowers
- Institute of Biosciences and Technology, Texas A&M Health, Houston, TX 77030, USA
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45
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Zhao X, Zhao Y, Du J, Gao P, Zhao K. The Interplay Among HIV, LINE-1, and the Interferon Signaling System. Front Immunol 2021; 12:732775. [PMID: 34566998 PMCID: PMC8459832 DOI: 10.3389/fimmu.2021.732775] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 08/20/2021] [Indexed: 12/17/2022] Open
Abstract
Human immunodeficiency viruses (HIVs) are retroviruses that replicate effectively in human CD4+ cells and cause the development of acquired immune deficiency syndrome (AIDS). On the other hand, type 1 long interspersed elements (LINE-1s or L1s) are the only active retroelements that can replicate autonomously in human cells. They, along with other active yet nonautonomous retroelements, have been associated with autoimmune diseases. There are many similarities between HIV and LINE-1. Being derived (or evolved) from ancient retroviruses, both HIV and LINE-1 replicate through a process termed reverse transcription, activate endogenous DNA and RNA sensors, trigger innate immune activation to promote interferon (IFN) expression, and are suppressed by protein products of interferon-stimulated genes (ISGs). However, these similarities make it difficult to decipher or even speculate the relationship between HIV and LINE-1, especially regarding the involvement of the IFN signaling system. In this review, we summarize previous findings on the relationships between HIV and innate immune activation as well as between LINE-1 and IFN upregulation. We also attempt to elucidate the interplay among HIV, LINE-1, and the IFN signaling system in hopes of guiding future research directions for viral suppression and immune regulation.
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Affiliation(s)
- Xu Zhao
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, China.,Department of Hepatology, First Hospital of Jilin University, Changchun, China
| | - Yifei Zhao
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, China
| | - Juan Du
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, China.,Key Laboratory of Organ Regeneration & Transplantation of the Ministry of Education, First Hospital of Jilin University, Changchun, China
| | - Pujun Gao
- Department of Hepatology, First Hospital of Jilin University, Changchun, China
| | - Ke Zhao
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, China.,Key Laboratory of Organ Regeneration & Transplantation of the Ministry of Education, First Hospital of Jilin University, Changchun, China
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46
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Formation of spermatogonia and fertile oocytes in golden hamsters requires piRNAs. Nat Cell Biol 2021; 23:992-1001. [PMID: 34489573 PMCID: PMC8437802 DOI: 10.1038/s41556-021-00746-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 07/27/2021] [Indexed: 12/20/2022]
Abstract
PIWI-interacting RNAs (piRNAs) support the germline by suppressing retrotransposons. Studies of the pathway in mice have strongly shaped the view that mammalian piRNAs are essential for male but not for female fertility. Here, we report that the role of the piRNA pathway substantially differs in golden hamsters (Mesocricetus auratus), the piRNA pathway setup of which more closely resembles that of other mammals, including humans. The loss of the Mov10l1 RNA helicase—an essential piRNA biogenesis factor—leads to striking phenotypes in both sexes. In contrast to mice, female Mov10l1–/– hamsters are sterile because their oocytes do not sustain zygotic development. Furthermore, Mov10l1–/– male hamsters have impaired establishment of spermatogonia accompanied by transcriptome dysregulation and an expression surge of a young retrotransposon subfamily. Our results show that the mammalian piRNA pathway has essential roles in both sexes and its adaptive nature allows it to manage emerging genomic threats and acquire new critical roles in the germline. A set of three papers reports that the piRNA pathway is essential for mammalian female fertility based on genetic perturbation experiments performed in golden hamsters.
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Hausmann F, Kurtz S. DeepGRP: engineering a software tool for predicting genomic repetitive elements using Recurrent Neural Networks with attention. Algorithms Mol Biol 2021; 16:20. [PMID: 34425870 PMCID: PMC8381506 DOI: 10.1186/s13015-021-00199-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 08/03/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Repetitive elements contribute a large part of eukaryotic genomes. For example, about 40 to 50% of human, mouse and rat genomes are repetitive. So identifying and classifying repeats is an important step in genome annotation. This annotation step is traditionally performed using alignment based methods, either in a de novo approach or by aligning the genome sequence to a species specific set of repetitive sequences. Recently, Li (Bioinformatics 35:4408-4410, 2019) developed a novel software tool dna-brnn to annotate repetitive sequences using a recurrent neural network trained on sample annotations of repetitive elements. RESULTS We have developed the methods of dna-brnn further and engineered a new software tool DeepGRP. This combines the basic concepts of Li (Bioinformatics 35:4408-4410, 2019) with current techniques developed for neural machine translation, the attention mechanism, for the task of nucleotide-level annotation of repetitive elements. An evaluation on the human genome shows a 20% improvement of the Matthews correlation coefficient for the predictions delivered by DeepGRP, when compared to dna-brnn. DeepGRP predicts two additional classes of repeats (compared to dna-brnn) and is able to transfer repeat annotations, using RepeatMasker-based training data to a different species (mouse). Additionally, we could show that DeepGRP predicts repeats annotated in the Dfam database, but not annotated by RepeatMasker. DeepGRP is highly scalable due to its implementation in the TensorFlow framework. For example, the GPU-accelerated version of DeepGRP is approx. 1.8 times faster than dna-brnn, approx. 8.6 times faster than RepeatMasker and over 100 times faster than HMMER searching for models of the Dfam database. CONCLUSIONS By incorporating methods from neural machine translation, DeepGRP achieves a consistent improvement of the quality of the predictions compared to dna-brnn. Improved running times are obtained by employing TensorFlow as implementation framework and the use of GPUs. By incorporating two additional classes of repeats, DeepGRP provides more complete annotations, which were evaluated against three state-of-the-art tools for repeat annotation.
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Affiliation(s)
- Fabian Hausmann
- Institute of Medical Systems Biology, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany
| | - Stefan Kurtz
- ZBH - Center for Bioinformatics, MIN-Fakultät, Universität Hamburg, Bundesstrasse 43, 20146 Hamburg, Germany
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Kim YG, Sung H, Shin HS, Kim MJ, Lee JS, Park SS, Seong MW. Intronic LINE-1 insertion in SLCO1B3 as a highly prevalent cause of rotor syndrome in East Asian population. J Hum Genet 2021; 67:71-77. [PMID: 34354231 DOI: 10.1038/s10038-021-00967-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/22/2021] [Accepted: 07/25/2021] [Indexed: 11/09/2022]
Abstract
Rotor syndrome is caused by digenic loss-of-function variants in SLCO1B1 and SLCO1B3 but only a few studies have reported co-occurring inactivating variants from both genes. A rotor syndrome-causing long interspersed element-1 (LINE-1) insertion in SLCO1B3 had been reported to be highly prevalent in the Japanese population but there has been no additional report. In spite of its known association with various human diseases, LINE-1 is hard to detect with current sequencing technologies. In this study, we aimed to devise a method to screen the LINE-1 insertion variant and investigate the frequency of this variant in various populations. A chimeric sequence, that was generated by concatenating the reference sequence at the junction and a part of inserted LINE-1 sequence, was searched from 725 raw sequencing data files. In cases containing the chimeric sequence, confirmatory long-range PCR and gap-PCR were performed. In total, 95 (13.1%) of 725 patients were positive for the chimeric sequence, and all were confirmed to have the SLCO1B3 LINE-1 insertion by PCR-based tests. The same chimeric sequence was searched from the 1000 Genomes Project data repository and the carrier frequency was remarkably high in the East Asian populations (10.1%), especially in Southern Han Chinese (18.5%), but almost absent in other populations. This SLCO1B3 LINE-1 insertion should be screened in a population-specific manner under suspicion of Rotor syndrome and the methods proposed in this study would enable this in a simple way.
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Affiliation(s)
- Young-Gon Kim
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hobin Sung
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ho Seob Shin
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Man Jin Kim
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jee-Soo Lee
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sung-Sup Park
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Moon-Woo Seong
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea.
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RNA m 6A modification orchestrates a LINE-1-host interaction that facilitates retrotransposition and contributes to long gene vulnerability. Cell Res 2021; 31:861-885. [PMID: 34108665 PMCID: PMC8324889 DOI: 10.1038/s41422-021-00515-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 04/27/2021] [Indexed: 02/06/2023] Open
Abstract
The molecular basis underlying the interaction between retrotransposable elements (RTEs) and the human genome remains poorly understood. Here, we profiled N6-methyladenosine (m6A) deposition on nascent RNAs in human cells by developing a new method MINT-Seq, which revealed that many classes of RTE RNAs, particularly intronic LINE-1s (L1s), are strongly methylated. These m6A-marked intronic L1s (MILs) are evolutionarily young, sense-oriented to hosting genes, and are bound by a dozen RNA binding proteins (RBPs) that are putative novel readers of m6A-modified RNAs, including a nuclear matrix protein SAFB. Notably, m6A positively controls the expression of both autonomous L1s and co-transcribed L1 relics, promoting L1 retrotransposition. We showed that MILs preferentially reside in long genes with critical roles in DNA damage repair and sometimes in L1 suppression per se, where they act as transcriptional "roadblocks" to impede the hosting gene expression, revealing a novel host-weakening strategy by the L1s. In counteraction, the host uses the SAFB reader complex to bind m6A-L1s to reduce their levels, and to safeguard hosting gene transcription. Remarkably, our analysis identified thousands of MILs in multiple human fetal tissues, enlisting them as a novel category of cell-type-specific regulatory elements that often compromise transcription of long genes and confer their vulnerability in neurodevelopmental disorders. We propose that this m6A-orchestrated L1-host interaction plays widespread roles in gene regulation, genome integrity, human development and diseases.
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Frassinelli L, Orecchini E, Al-Wardat S, Tripodi M, Mancone C, Doria M, Galardi S, Ciafrè SA, Michienzi A. The RNA editing enzyme ADAR2 restricts L1 mobility. RNA Biol 2021; 18:75-87. [PMID: 34224323 PMCID: PMC8677026 DOI: 10.1080/15476286.2021.1940020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Adenosine deaminases acting on RNA (ADARs) are enzymes that convert adenosines to inosines in double-stranded RNAs (RNA editing A-to-I). ADAR1 and ADAR2 were previously reported as HIV-1 proviral factors. The aim of this study was to investigate the composition of the ADAR2 ribonucleoprotein complex during HIV-1 expression. By using a dual-tag affinity purification procedure in cells expressing HIV-1 followed by mass spectrometry analysis, we identified 10 non-ribosomal ADAR2-interacting factors. A significant fraction of these proteins was previously found associated to the Long INterspersed Element 1 (LINE1 or L1) ribonucleoparticles and to regulate the life cycle of L1 retrotransposons. Considering that we previously demonstrated that ADAR1 is an inhibitor of LINE-1 retrotransposon activity, we investigated whether also ADAR2 played a similar function. To reach this goal, we performed specific cell culture retrotransposition assays in cells overexpressing or ablated for ADAR2. These experiments unveil a novel function of ADAR2 as suppressor of L1 retrotransposition. Furthermore, we showed that ADAR2 binds the basal L1 RNP complex. Overall, these data support the role of ADAR2 as regulator of L1 life cycle.
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Affiliation(s)
- Loredana Frassinelli
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Rome, Italy
| | - Elisa Orecchini
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Rome, Italy
| | - Sofian Al-Wardat
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Rome, Italy
| | - Marco Tripodi
- National Institute for Infectious Diseases L. Spallanzani, IRCCS, Rome, Italy.,Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Carmine Mancone
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Margherita Doria
- Unit of Primary Immunodeficiency, Bambino Gesu` Children's Hospital, IRCCS, 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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