1
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Deaville LA, Berrens RV. Technology to the rescue: how to uncover the role of transposable elements in preimplantation development. Biochem Soc Trans 2024; 52:1349-1362. [PMID: 38752836 PMCID: PMC11346443 DOI: 10.1042/bst20231262] [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: 02/14/2024] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 06/27/2024]
Abstract
Transposable elements (TEs) are highly expressed in preimplantation development. Preimplantation development is the phase when the cells of the early embryo undergo the first cell fate choice and change from being totipotent to pluripotent. A range of studies have advanced our understanding of TEs in preimplantation, as well as their epigenetic regulation and functional roles. However, many questions remain about the implications of TE expression during early development. Challenges originate first due to the abundance of TEs in the genome, and second because of the limited cell numbers in preimplantation. Here we review the most recent technological advancements promising to shed light onto the role of TEs in preimplantation development. We explore novel avenues to identify genomic TE insertions and improve our understanding of the regulatory mechanisms and roles of TEs and their RNA and protein products during early development.
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Affiliation(s)
- Lauryn A. Deaville
- Institute for Developmental and Regenerative Medicine, Oxford University, IMS-Tetsuya Nakamura Building, Old Road Campus, Roosevelt Dr, Oxford OX3 7TY, U.K
- Department of Paediatrics, Oxford University, Level 2, Children's Hospital, John Radcliffe Headington, Oxford OX3 9DU, U.K
- MRC Weatherall Institute of Molecular Medicine, Oxford University, John Radcliffe Hospital, Oxford OX3 9DS, U.K
| | - Rebecca V. Berrens
- Institute for Developmental and Regenerative Medicine, Oxford University, IMS-Tetsuya Nakamura Building, Old Road Campus, Roosevelt Dr, Oxford OX3 7TY, U.K
- Department of Paediatrics, Oxford University, Level 2, Children's Hospital, John Radcliffe Headington, Oxford OX3 9DU, U.K
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2
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Wang ZY, Ge LP, Ouyang Y, Jin X, Jiang YZ. Targeting transposable elements in cancer: developments and opportunities. Biochim Biophys Acta Rev Cancer 2024; 1879:189143. [PMID: 38936517 DOI: 10.1016/j.bbcan.2024.189143] [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: 12/07/2023] [Revised: 05/23/2024] [Accepted: 06/19/2024] [Indexed: 06/29/2024]
Abstract
Transposable elements (TEs), comprising nearly 50% of the human genome, have transitioned from being perceived as "genomic junk" to key players in cancer progression. Contemporary research links TE regulatory disruptions with cancer development, underscoring their therapeutic potential. Advances in long-read sequencing, computational analytics, single-cell sequencing, proteomics, and CRISPR-Cas9 technologies have enriched our understanding of TEs' clinical implications, notably their impact on genome architecture, gene regulation, and evolutionary processes. In cancer, TEs, including long interspersed element-1 (LINE-1), Alus, and long terminal repeat (LTR) elements, demonstrate altered patterns, influencing both tumorigenic and tumor-suppressive mechanisms. TE-derived nucleic acids and tumor antigens play critical roles in tumor immunity, bridging innate and adaptive responses. Given their central role in oncology, TE-targeted therapies, particularly through reverse transcriptase inhibitors and epigenetic modulators, represent a novel avenue in cancer treatment. Combining these TE-focused strategies with existing chemotherapy or immunotherapy regimens could enhance efficacy and offer a new dimension in cancer treatment. This review delves into recent TE detection advancements, explores their multifaceted roles in tumorigenesis and immune regulation, discusses emerging diagnostic and therapeutic approaches centered on TEs, and anticipates future directions in cancer research.
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Affiliation(s)
- Zi-Yu Wang
- Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Li-Ping Ge
- Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Yang Ouyang
- Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Xi Jin
- Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Yi-Zhou Jiang
- Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China.
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3
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Pabis K, Barardo D, Sirbu O, Selvarajoo K, Gruber J, Kennedy BK. A concerted increase in readthrough and intron retention drives transposon expression during aging and senescence. eLife 2024; 12:RP87811. [PMID: 38567944 PMCID: PMC10990488 DOI: 10.7554/elife.87811] [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] [Indexed: 04/05/2024] Open
Abstract
Aging and senescence are characterized by pervasive transcriptional dysfunction, including increased expression of transposons and introns. Our aim was to elucidate mechanisms behind this increased expression. Most transposons are found within genes and introns, with a large minority being close to genes. This raises the possibility that transcriptional readthrough and intron retention are responsible for age-related changes in transposon expression rather than expression of autonomous transposons. To test this, we compiled public RNA-seq datasets from aged human fibroblasts, replicative and drug-induced senescence in human cells, and RNA-seq from aging mice and senescent mouse cells. Indeed, our reanalysis revealed a correlation between transposons expression, intron retention, and transcriptional readthrough across samples and within samples. Both intron retention and readthrough increased with aging or cellular senescence and these transcriptional defects were more pronounced in human samples as compared to those of mice. In support of a causal connection between readthrough and transposon expression, analysis of models showing induced transcriptional readthrough confirmed that they also show elevated transposon expression. Taken together, our data suggest that elevated transposon reads during aging seen in various RNA-seq dataset are concomitant with multiple transcriptional defects. Intron retention and transcriptional readthrough are the most likely explanation for the expression of transposable elements that lack a functional promoter.
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Affiliation(s)
- Kamil Pabis
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of SingaporeSingaporeSingapore
- Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of SingaporeSingaporeSingapore
- Centre for Healthy Longevity, National University Health SystemSingaporeSingapore
| | - Diogo Barardo
- Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of SingaporeSingaporeSingapore
- Centre for Healthy Longevity, National University Health SystemSingaporeSingapore
| | - Olga Sirbu
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR)SingaporeSingapore
| | - Kumar Selvarajoo
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR)SingaporeSingapore
- Singapore Institute of Food and Biotechnology Innovation, Agency for Science, Technology and Research (A*STAR)SingaporeSingapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of SingaporeSingaporeSingapore
- School of Biological Sciences, Nanyang Technological UniversitySingaporeSingapore
| | - Jan Gruber
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of SingaporeSingaporeSingapore
- Science Divisions, Yale-NUS CollegeSingaporeSingapore
| | - Brian K Kennedy
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of SingaporeSingaporeSingapore
- Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of SingaporeSingaporeSingapore
- Centre for Healthy Longevity, National University Health SystemSingaporeSingapore
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4
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Lee M, Ahmad SF, Xu J. Regulation and function of transposable elements in cancer genomes. Cell Mol Life Sci 2024; 81:157. [PMID: 38556602 PMCID: PMC10982106 DOI: 10.1007/s00018-024-05195-2] [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: 12/03/2023] [Revised: 02/28/2024] [Accepted: 03/01/2024] [Indexed: 04/02/2024]
Abstract
Over half of human genomic DNA is composed of repetitive sequences generated throughout evolution by prolific mobile genetic parasites called transposable elements (TEs). Long disregarded as "junk" or "selfish" DNA, TEs are increasingly recognized as formative elements in genome evolution, wired intimately into the structure and function of the human genome. Advances in sequencing technologies and computational methods have ushered in an era of unprecedented insight into how TE activity impacts human biology in health and disease. Here we discuss the current views on how TEs have shaped the regulatory landscape of the human genome, how TE activity is implicated in human cancers, and how recent findings motivate novel strategies to leverage TE activity for improved cancer therapy. Given the crucial role of methodological advances in TE biology, we pair our conceptual discussions with an in-depth review of the inherent technical challenges in studying repeats, specifically related to structural variation, expression analyses, and chromatin regulation. Lastly, we provide a catalog of existing and emerging assays and bioinformatic software that altogether are enabling the most sophisticated and comprehensive investigations yet into the regulation and function of interspersed repeats in cancer genomes.
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Affiliation(s)
- Michael Lee
- Department of Pediatrics, Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX, 75390, USA.
| | - Syed Farhan Ahmad
- Department of Pathology, Center of Excellence for Leukemia Studies, St. Jude Children's Research Hospital, 262 Danny Thomas Place - MS 345, Memphis, TN, 38105, USA
| | - Jian Xu
- Department of Pathology, Center of Excellence for Leukemia Studies, St. Jude Children's Research Hospital, 262 Danny Thomas Place - MS 345, Memphis, TN, 38105, USA.
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5
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Perkiö A, Pradhan B, Genc F, Pirttikoski A, Pikkusaari S, Erkan EP, Falco MM, Huhtinen K, Narva S, Hynninen J, Kauppi L, Vähärautio A. Locus-specific LINE-1 expression in clinical ovarian cancer specimens at the single-cell level. Sci Rep 2024; 14:4322. [PMID: 38383551 PMCID: PMC10881972 DOI: 10.1038/s41598-024-54113-w] [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: 07/02/2023] [Accepted: 02/08/2024] [Indexed: 02/23/2024] Open
Abstract
Long interspersed nuclear elements (LINE-1s/L1s) are a group of retrotransposons that can copy themselves within a genome. In humans, it is the most successful transposon in nucleotide content. L1 expression is generally mild in normal human tissues, but the activity has been shown to increase significantly in many cancers. Few studies have examined L1 expression at single-cell resolution, thus it is undetermined whether L1 reactivation occurs solely in malignant cells within tumors. One of the cancer types with frequent L1 activity is high-grade serous ovarian carcinoma (HGSOC). Here, we identified locus-specific L1 expression with 3' single-cell RNA sequencing in pre- and post-chemotherapy HGSOC sample pairs from 11 patients, and in fallopian tube samples from five healthy women. Although L1 expression quantification with the chosen technique was challenging due to the repetitive nature of the element, we found evidence of L1 expression primarily in cancer cells, but also in other cell types, e.g. cancer-associated fibroblasts. The expression levels were similar in samples taken before and after neoadjuvant chemotherapy, indicating that L1 transcriptional activity was unaffected by clinical platinum-taxane treatment. Furthermore, L1 activity was negatively associated with the expression of MYC target genes, a finding that supports earlier literature of MYC being an L1 suppressor.
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Affiliation(s)
- Anna Perkiö
- Research Program in Systems Oncology, Research Programs Unit, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland
| | - Barun Pradhan
- Research Program in Systems Oncology, Research Programs Unit, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
- New York Genome Center, New York, NY, USA
| | - Fatih Genc
- Research Program in Systems Oncology, Research Programs Unit, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland
| | - Anna Pirttikoski
- Research Program in Systems Oncology, Research Programs Unit, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland
| | - Sanna Pikkusaari
- Research Program in Systems Oncology, Research Programs Unit, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland
| | - Erdogan Pekcan Erkan
- Research Program in Systems Oncology, Research Programs Unit, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Matias Marin Falco
- Research Program in Systems Oncology, Research Programs Unit, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland
| | - Kaisa Huhtinen
- Research Program in Systems Oncology, Research Programs Unit, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland
- Institute of Biomedicine and FICAN West Cancer Centre, University of Turku and Turku University Hospital, 20521, Turku, Finland
| | - Sara Narva
- Department of Obstetrics and Gynecology, University of Turku and Turku University Hospital, 20521, Turku, Finland
| | - Johanna Hynninen
- Department of Obstetrics and Gynecology, University of Turku and Turku University Hospital, 20521, Turku, Finland
| | - Liisa Kauppi
- Research Program in Systems Oncology, Research Programs Unit, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland.
| | - Anna Vähärautio
- Research Program in Systems Oncology, Research Programs Unit, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland.
- Foundation for the Finnish Cancer Institute (FCI), Helsinki, Finland.
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6
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Lanciano S, Philippe C, Sarkar A, Pratella D, Domrane C, Doucet AJ, van Essen D, Saccani S, Ferry L, Defossez PA, Cristofari G. Locus-level L1 DNA methylation profiling reveals the epigenetic and transcriptional interplay between L1s and their integration sites. CELL GENOMICS 2024; 4:100498. [PMID: 38309261 PMCID: PMC10879037 DOI: 10.1016/j.xgen.2024.100498] [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: 06/02/2023] [Revised: 07/20/2023] [Accepted: 01/09/2024] [Indexed: 02/05/2024]
Abstract
Long interspersed element 1 (L1) retrotransposons are implicated in human disease and evolution. Their global activity is repressed by DNA methylation, but deciphering the regulation of individual copies has been challenging. Here, we combine short- and long-read sequencing to unveil L1 methylation heterogeneity across cell types, families, and individual loci and elucidate key principles involved. We find that the youngest primate L1 families are specifically hypomethylated in pluripotent stem cells and the placenta but not in most tumors. Locally, intronic L1 methylation is intimately associated with gene transcription. Conversely, the L1 methylation state can propagate to the proximal region up to 300 bp. This phenomenon is accompanied by the binding of specific transcription factors, which drive the expression of L1 and chimeric transcripts. Finally, L1 hypomethylation alone is typically insufficient to trigger L1 expression due to redundant silencing pathways. Our results illuminate the epigenetic and transcriptional interplay between retrotransposons and their host genome.
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Affiliation(s)
- Sophie Lanciano
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Claude Philippe
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Arpita Sarkar
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - David Pratella
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Cécilia Domrane
- University Paris Cité, CNRS, Epigenetics and Cell Fate, Paris, France
| | - Aurélien J Doucet
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Dominic van Essen
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Simona Saccani
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France
| | - Laure Ferry
- University Paris Cité, CNRS, Epigenetics and Cell Fate, Paris, France
| | | | - Gael Cristofari
- University Cote d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging of Nice (IRCAN), Nice, France.
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7
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Singh S, Borkar MR, Bhatt LK. Transposable Elements: Emerging Therapeutic Targets in Neurodegenerative Diseases. Neurotox Res 2024; 42:9. [PMID: 38270797 DOI: 10.1007/s12640-024-00688-1] [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: 09/26/2023] [Revised: 01/14/2024] [Accepted: 01/17/2024] [Indexed: 01/26/2024]
Abstract
Neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), are characterized by the progressive loss of neuronal function and structure. While several genetic and environmental factors have been implicated in the pathogenesis of these disorders, emerging evidence suggests that transposable elements (TEs), once considered "junk DNA," play a significant role in their development and progression. TEs are mobile genetic elements capable of moving within the genome, and their dysregulation has been associated with genomic instability, altered gene expression, and neuroinflammation. This review provides an overview of TEs, including long interspersed nuclear elements (LINEs), short interspersed nuclear elements (SINEs), and endogenous retroviruses (ERVs), mechanisms of repression and derepression, and their potential impact on neurodegeneration. The evidence linking TEs to AD, PD, and ALS by shedding light on the complex interactions between TEs and neurodegeneration has been discussed. Furthermore, the therapeutic potential of targeting TEs in neurodegenerative diseases has been explored. Understanding the role of TEs in neurodegeneration holds promise for developing novel therapeutic strategies aimed at mitigating disease progression and preserving neuronal health.
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Affiliation(s)
- Shrishti Singh
- Department of Pharmacology, Bhanuben Nanavati College of Pharmacy, SVKM's DrVile Parle (W), Mumbai, India
| | - Maheshkumar R Borkar
- Department of Pharmaceutical Chemistry, SVKM's Dr, Bhanuben Nanavati College of Pharmacy, Vile Parle (W), Mumbai, India
| | - Lokesh Kumar Bhatt
- Department of Pharmacology, Bhanuben Nanavati College of Pharmacy, SVKM's DrVile Parle (W), Mumbai, India.
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8
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Kines KJ, Sokolowski M, DeFreece C, Shareef A, deHaro DL, Belancio VP. Large Deletions, Cleavage of the Telomeric Repeat Sequence, and Reverse Transcriptase-Mediated DNA Damage Response Associated with Long Interspersed Element-1 ORF2p Enzymatic Activities. Genes (Basel) 2024; 15:143. [PMID: 38397133 PMCID: PMC10887698 DOI: 10.3390/genes15020143] [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: 12/22/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 02/25/2024] Open
Abstract
L1 elements can cause DNA damage and genomic variation via retrotransposition and the generation of endonuclease-dependent DNA breaks. These processes require L1 ORF2p protein that contains an endonuclease domain, which cuts genomic DNA, and a reverse transcriptase domain, which synthesizes cDNA. The complete impact of L1 enzymatic activities on genome stability and cellular function remains understudied, and the spectrum of L1-induced mutations, other than L1 insertions, is mostly unknown. Using an inducible system, we demonstrate that an ORF2p containing functional reverse transcriptase is sufficient to elicit DNA damage response even in the absence of the functional endonuclease. Using a TK/Neo reporter system that captures misrepaired DNA breaks, we demonstrate that L1 expression results in large genomic deletions that lack any signatures of L1 involvement. Using an in vitro cleavage assay, we demonstrate that L1 endonuclease efficiently cuts telomeric repeat sequences. These findings support that L1 could be an unrecognized source of disease-promoting genomic deletions, telomere dysfunction, and an underappreciated source of chronic RT-mediated DNA damage response in mammalian cells. Our findings expand the spectrum of biological processes that can be triggered by functional and nonfunctional L1s, which have impactful evolutionary- and health-relevant consequences.
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Affiliation(s)
- Kristine J. Kines
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, USA
| | - Mark Sokolowski
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, USA
| | - Cecily DeFreece
- Department of Biology, Xavier University of Louisiana, New Orleans, LA 70125, USA
| | - Afzaal Shareef
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, USA
| | - Dawn L. deHaro
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, USA
| | - Victoria P. Belancio
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, USA
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9
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Mendez-Dorantes C, Burns KH. LINE-1 retrotransposition and its deregulation in cancers: implications for therapeutic opportunities. Genes Dev 2023; 37:948-967. [PMID: 38092519 PMCID: PMC10760644 DOI: 10.1101/gad.351051.123] [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] [Indexed: 12/28/2023]
Abstract
Long interspersed element 1 (LINE-1) is the only protein-coding transposon that is active in humans. LINE-1 propagates in the genome using RNA intermediates via retrotransposition. This activity has resulted in LINE-1 sequences occupying approximately one-fifth of our genome. Although most copies of LINE-1 are immobile, ∼100 copies are retrotransposition-competent. Retrotransposition is normally limited via epigenetic silencing, DNA repair, and other host defense mechanisms. In contrast, LINE-1 overexpression and retrotransposition are hallmarks of cancers. Here, we review mechanisms of LINE-1 regulation and how LINE-1 may promote genetic heterogeneity in tumors. Finally, we discuss therapeutic strategies to exploit LINE-1 biology in cancers.
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Affiliation(s)
- Carlos Mendez-Dorantes
- Department of Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA;
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
| | - Kathleen H Burns
- Department of Pathology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA;
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts 02142, USA
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10
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Li Z, Duan S, Hua X, Xu X, Li Y, Menolfi D, Zhou H, Lu C, Zha S, Goff SP, Zhang Z. Asymmetric distribution of parental H3K9me3 in S phase silences L1 elements. Nature 2023; 623:643-651. [PMID: 37938774 PMCID: PMC11034792 DOI: 10.1038/s41586-023-06711-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/04/2023] [Indexed: 11/08/2023]
Abstract
In eukaryotes, repetitive DNA sequences are transcriptionally silenced through histone H3 lysine 9 trimethylation (H3K9me3). Loss of silencing of the repeat elements leads to genome instability and human diseases, including cancer and ageing1-3. Although the role of H3K9me3 in the establishment and maintenance of heterochromatin silencing has been extensively studied4-6, the pattern and mechanism that underlie the partitioning of parental H3K9me3 at replicating DNA strands are unknown. Here we report that H3K9me3 is preferentially transferred onto the leading strands of replication forks, which occurs predominantly at long interspersed nuclear element (LINE) retrotransposons (also known as LINE-1s or L1s) that are theoretically transcribed in the head-on direction with replication fork movement. Mechanistically, the human silencing hub (HUSH) complex interacts with the leading-strand DNA polymerase Pol ε and contributes to the asymmetric segregation of H3K9me3. Cells deficient in Pol ε subunits (POLE3 and POLE4) or the HUSH complex (MPP8 and TASOR) show compromised H3K9me3 asymmetry and increased LINE expression. Similar results were obtained in cells expressing a MPP8 mutant defective in H3K9me3 binding and in TASOR mutants with reduced interactions with Pol ε. These results reveal an unexpected mechanism whereby the HUSH complex functions with Pol ε to promote asymmetric H3K9me3 distribution at head-on LINEs to suppress their expression in S phase.
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Affiliation(s)
- Zhiming Li
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Shoufu Duan
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Xu Hua
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Xiaowei Xu
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Yinglu Li
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Demis Menolfi
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
| | - Hui Zhou
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Chao Lu
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Shan Zha
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
- Departments of Pathology and Cell Biology, Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA
| | - Stephen P Goff
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
- Departments of Biochemistry and Molecular Biophysics, Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA
| | - Zhiguo Zhang
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA.
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA.
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA.
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA.
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11
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Luqman-Fatah A, Miyoshi T. Human LINE-1 retrotransposons: impacts on the genome and regulation by host factors. Genes Genet Syst 2023; 98:121-154. [PMID: 36436935 DOI: 10.1266/ggs.22-00038] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Genome sequencing revealed that nearly half of the human genome is comprised of transposable elements. Although most of these elements have been rendered inactive due to mutations, full-length intact long interspersed element-1 (LINE-1 or L1) copies retain the ability to mobilize through RNA intermediates by a so-called "copy-and-paste" mechanism, termed retrotransposition. L1 is the only known autonomous mobile genetic element in the genome, and its retrotransposition contributes to inter- or intra-individual genetic variation within the human population. However, L1 retrotransposition also poses a threat to genome integrity due to gene disruption and chromosomal instability. Moreover, recent studies suggest that aberrant L1 expression can impact human health by causing diseases such as cancer and chronic inflammation that might lead to autoimmune disorders. To counteract these adverse effects, the host cells have evolved multiple layers of defense mechanisms at the epigenetic, RNA and protein levels. Intriguingly, several host factors have also been reported to facilitate L1 retrotransposition, suggesting that there is competition between negative and positive regulation of L1 by host factors. Here, we summarize the known host proteins that regulate L1 activity at different stages of the replication cycle and discuss how these factors modulate disease-associated phenotypes caused by L1.
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Affiliation(s)
- Ahmad Luqman-Fatah
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University
- Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University
| | - Tomoichiro Miyoshi
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University
- Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University
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12
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Rybacki K, Xia M, Ahsan MU, Xing J, Wang K. Assessing the Expression of Long INterspersed Elements (LINEs) via Long-Read Sequencing in Diverse Human Tissues and Cell Lines. Genes (Basel) 2023; 14:1893. [PMID: 37895242 PMCID: PMC10606529 DOI: 10.3390/genes14101893] [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: 09/04/2023] [Revised: 09/21/2023] [Accepted: 09/27/2023] [Indexed: 10/29/2023] Open
Abstract
Transposable elements, such as Long INterspersed Elements (LINEs), are DNA sequences that can replicate within genomes. LINEs replicate using an RNA intermediate followed by reverse transcription and are typically a few kilobases in length. LINE activity creates genomic structural variants in human populations and leads to somatic alterations in cancer genomes. Long-read RNA sequencing technologies, including Oxford Nanopore and PacBio, can directly sequence relatively long transcripts, thus providing the opportunity to examine full-length LINE transcripts. This study focuses on the development of a new bioinformatics pipeline for the identification and quantification of active, full-length LINE transcripts in diverse human tissues and cell lines. In our pipeline, we utilized RepeatMasker to identify LINE-1 (L1) transcripts from long-read transcriptome data and incorporated several criteria, such as transcript start position, divergence, and length, to remove likely false positives. Comparisons between cancerous and normal cell lines, as well as human tissue samples, revealed elevated expression levels of young LINEs in cancer, particularly at intact L1 loci. By employing bioinformatics methodologies on long-read transcriptome data, this study demonstrates the landscape of L1 expression in tissues and cell lines.
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Affiliation(s)
- Karleena Rybacki
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA; (K.R.); (M.X.)
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA;
| | - Mingyi Xia
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA; (K.R.); (M.X.)
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA;
| | - Mian Umair Ahsan
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA;
| | - Jinchuan Xing
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
- Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Kai Wang
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA; (K.R.); (M.X.)
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA;
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13
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Gerdes P, Chan D, Lundberg M, Sanchez-Luque FJ, Bodea GO, Ewing AD, Faulkner GJ, Richardson SR. Locus-resolution analysis of L1 regulation and retrotransposition potential in mouse embryonic development. Genome Res 2023; 33:1465-1481. [PMID: 37798118 PMCID: PMC10620060 DOI: 10.1101/gr.278003.123] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/21/2023] [Indexed: 10/07/2023]
Abstract
Mice harbor ∼2800 intact copies of the retrotransposon Long Interspersed Element 1 (L1). The in vivo retrotransposition capacity of an L1 copy is defined by both its sequence integrity and epigenetic status, including DNA methylation of the monomeric units constituting young mouse L1 promoters. Locus-specific L1 methylation dynamics during development may therefore elucidate and explain spatiotemporal niches of endogenous retrotransposition but remain unresolved. Here, we interrogate the retrotransposition efficiency and epigenetic fate of source (donor) L1s, identified as mobile in vivo. We show that promoter monomer loss consistently attenuates the relative retrotransposition potential of their offspring (daughter) L1 insertions. We also observe that most donor/daughter L1 pairs are efficiently methylated upon differentiation in vivo and in vitro. We use Oxford Nanopore Technologies (ONT) long-read sequencing to resolve L1 methylation genome-wide and at individual L1 loci, revealing a distinctive "smile" pattern in methylation levels across the L1 promoter region. Using Pacific Biosciences (PacBio) SMRT sequencing of L1 5' RACE products, we then examine DNA methylation dynamics at the mouse L1 promoter in parallel with transcription start site (TSS) distribution at locus-specific resolution. Together, our results offer a novel perspective on the interplay between epigenetic repression, L1 evolution, and genome stability.
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Affiliation(s)
- Patricia Gerdes
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
| | - Dorothy Chan
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
| | - Mischa Lundberg
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
- The University of Queensland Diamantina Institute, The University of Queensland, Woolloongabba, Queensland 4102, Australia
- Translational Bioinformatics, Commonwealth Scientific and Industrial Research Organisation, Sydney, New South Wales 2113, Australia
| | - Francisco J Sanchez-Luque
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
- GENYO. Centre for Genomics and Oncological Research (Pfizer-University of Granada-Andalusian Regional Government), PTS Granada, 18016, Spain
- MRC Human Genetics Unit, Institute of Genetics and Cancer (IGC), University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, United Kingdom
| | - Gabriela O Bodea
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Adam D Ewing
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia
| | - Geoffrey J Faulkner
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia;
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Sandra R Richardson
- Mater Research Institute - University of Queensland, TRI Building, Woolloongabba, Queensland 4102, Australia;
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14
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Goodier JL, Wan H, Soares AO, Sanchez L, Selser JM, Pereira GC, Karma S, García-Pérez JL, Kazazian HH, García Cañadas MM. ZCCHC3 is a stress granule zinc knuckle protein that strongly suppresses LINE-1 retrotransposition. PLoS Genet 2023; 19:e1010795. [PMID: 37405998 DOI: 10.1371/journal.pgen.1010795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 05/23/2023] [Indexed: 07/07/2023] Open
Abstract
Retrotransposons have generated about half of the human genome and LINE-1s (L1s) are the only autonomously active retrotransposons. The cell has evolved an arsenal of defense mechanisms to protect against retrotransposition with factors we are only beginning to understand. In this study, we investigate Zinc Finger CCHC-Type Containing 3 (ZCCHC3), a gag-like zinc knuckle protein recently reported to function in the innate immune response to infecting viruses. We show that ZCCHC3 also severely restricts human retrotransposons and associates with the L1 ORF1p ribonucleoprotein particle. We identify ZCCHC3 as a bona fide stress granule protein, and its association with LINE-1 is further supported by colocalization with L1 ORF1 protein in stress granules, dense cytoplasmic aggregations of proteins and RNAs that contain stalled translation pre-initiation complexes and form when the cell is under stress. Our work also draws links between ZCCHC3 and the anti-viral and retrotransposon restriction factors Mov10 RISC Complex RNA Helicase (MOV10) and Zinc Finger CCCH-Type, Antiviral 1 (ZC3HAV1, also called ZAP). Furthermore, collective evidence from subcellular localization, co-immunoprecipitation, and velocity gradient centrifugation connects ZCCHC3 with the RNA exosome, a multi-subunit ribonuclease complex capable of degrading various species of RNA molecules and that has previously been linked with retrotransposon control.
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Affiliation(s)
- John L Goodier
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Han Wan
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alisha O Soares
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Laura Sanchez
- GENYO, Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
| | - John Michael Selser
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Gavin C Pereira
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sadik Karma
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jose Luis García-Pérez
- GENYO, Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
| | - Haig H Kazazian
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Marta M García Cañadas
- GENYO, Centre for Genomics and Oncological Research: Pfizer, University of Granada, Andalusian Regional Government, Granada, Spain
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15
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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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16
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McKerrow W, Kagermazova L, Doudican N, Frazzette N, Kaparos E, Evans SA, Rocha A, Sedivy JM, Neretti N, Carucci J, Boeke J, Fenyö D. LINE-1 retrotransposon expression in cancerous, epithelial and neuronal cells revealed by 5' single-cell RNA-Seq. Nucleic Acids Res 2023; 51:2033-2045. [PMID: 36744437 PMCID: PMC10018344 DOI: 10.1093/nar/gkad049] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 01/11/2023] [Accepted: 01/17/2023] [Indexed: 02/07/2023] Open
Abstract
LINE-1 retrotransposons are sequences capable of copying themselves to new genomic loci via an RNA intermediate. New studies implicate LINE-1 in a range of diseases, especially in the context of aging, but without an accurate understanding of where and when LINE-1 is expressed, a full accounting of its role in health and disease is not possible. We therefore developed a method-5' scL1seq-that makes use of a widely available library preparation method (10x Genomics 5' single cell RNA-seq) to measure LINE-1 expression in tens of thousands of single cells. We recapitulated the known pattern of LINE-1 expression in tumors-present in cancer cells, absent from immune cells-and identified hitherto undescribed LINE-1 expression in human epithelial cells and mouse hippocampal neurons. In both cases, we saw a modest increase with age, supporting recent research connecting LINE-1 to age related diseases.
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Affiliation(s)
- Wilson McKerrow
- Institute for Systems Genetics, NYU Langone Health, New York, NY, USA
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY, USA
| | - Larisa Kagermazova
- Institute for Systems Genetics, NYU Langone Health, New York, NY, USA
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY, USA
| | - Nicole Doudican
- Ronald O. Perelman Department of Dermatology, NYU Langone Health, New York, NY, USA
| | - Nicholas Frazzette
- Ronald O. Perelman Department of Dermatology, NYU Langone Health, New York, NY, USA
| | - Efiyenia Ismini Kaparos
- Institute for Systems Genetics, NYU Langone Health, New York, NY, USA
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY, USA
| | - Shane A Evans
- Center for Computational Molecular Biology, Brown University, Providence, RI, USA
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
| | - Azucena Rocha
- Center for Computational Molecular Biology, Brown University, Providence, RI, USA
- Department of Molecular Biology, Cell Biology, and Biochemistry, 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
| | - Nicola Neretti
- Center for Computational Molecular Biology, Brown University, Providence, RI, USA
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
| | - John Carucci
- Ronald O. Perelman Department of Dermatology, NYU Langone Health, New York, NY, USA
| | - Jef D Boeke
- Institute for Systems Genetics, NYU Langone Health, New York, NY, USA
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY, USA
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn,NY11201, USA
| | - David Fenyö
- Institute for Systems Genetics, NYU Langone Health, New York, NY, USA
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY, USA
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17
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Smits N, Faulkner GJ. Nanopore Sequencing to Identify Transposable Element Insertions and Their Epigenetic Modifications. Methods Mol Biol 2023; 2607:151-171. [PMID: 36449163 DOI: 10.1007/978-1-0716-2883-6_9] [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: 06/17/2023]
Abstract
Over the past 20 years, high-throughput genomic assays have fundamentally changed how transposable elements (TEs) are studied. While short-read DNA sequencing has been at the heart of these efforts, novel technologies that generate longer reads are driving a shift in the field. Long-read sequencing now permits locus-specific approaches to locate individual TE insertions and understand their epigenetic and transcriptional regulation, while still profiling TE activity genome-wide. Here we provide detailed guidelines to implement Oxford Nanopore Technologies (ONT) sequencing to identify polymorphic TE insertions and profile TE epigenetic landscapes. Using human long interspersed element-1 (LINE-1, L1) as an example, we explain the procedures involved, including final visualization, and potential bottlenecks and pitfalls. ONT sequencing will be, in our view, a workhorse technology for the foreseeable future in the TE field.
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Affiliation(s)
- Nathan Smits
- Mater Research Institute, University of Queensland, Woolloongabba, QLD, Australia
| | - Geoffrey J Faulkner
- Mater Research Institute, University of Queensland, Woolloongabba, QLD, Australia.
- Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia.
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18
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McKerrow W. Quantification of LINE-1 RNA Expression from Bulk RNA-seq Using L1EM. Methods Mol Biol 2023; 2607:115-126. [PMID: 36449161 DOI: 10.1007/978-1-0716-2883-6_7] [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
LINE-1 retrotransposons have the potential to cause DNA damage, contribute to genome instability, and induce an interferon response. Thus, accurate measurements of their expression, especially in disease contexts where genome instability and the interferon response are relevant, are of particular importance. Illumina-based bulk RNA sequencing remains the most abundant datatype for measuring gene expression. However, "active" expression from its own internal promoter is only one source of LINE-1 aligning reads in an RNA-seq experiment. With about half a million LINE-1 sequences scattered throughout the genome, many are incorporated into other transcripts that have nothing to do with LINE-1 activity. We call this "passive" co-transcription. Here we will describe how to use L1EM, a computational method that separates active from passive LINE-1 expression at the locus-specific level.
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Affiliation(s)
- Wilson McKerrow
- Institute for Systems Genetics, NYU Langone Health, New York, NY, USA.
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19
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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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20
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Esposito M, Gualandi N, Spirito G, Ansaloni F, Gustincich S, Sanges R. Transposons Acting as Competitive Endogenous RNAs: In-Silico Evidence from Datasets Characterised by L1 Overexpression. Biomedicines 2022; 10:biomedicines10123279. [PMID: 36552034 PMCID: PMC9776036 DOI: 10.3390/biomedicines10123279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/07/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022] Open
Abstract
LINE L1 are transposable elements that can replicate within the genome by passing through RNA intermediates. The vast majority of these element copies in the human genome are inactive and just between 100 and 150 copies are still able to mobilize. During evolution, they could have been positively selected for beneficial cellular functions. Nonetheless, L1 deregulation can be detrimental to the cell, causing diseases such as cancer. The activity of miRNAs represents a fundamental mechanism for controlling transcript levels in somatic cells. These are a class of small non-coding RNAs that cause degradation or translational inhibition of their target transcripts. Beyond this, competitive endogenous RNAs (ceRNAs), mostly made by circular and non-coding RNAs, have been seen to compete for the binding of the same set of miRNAs targeting protein coding genes. In this study, we have investigated whether autonomously transcribed L1s may act as ceRNAs by analyzing public dataset in-silico. We observed that genes sharing miRNA target sites with L1 have a tendency to be upregulated when L1 are overexpressed, suggesting the possibility that L1 might act as ceRNAs. This finding will help in the interpretation of transcriptomic responses in contexts characterized by the specific activation of transposons.
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Affiliation(s)
- Mauro Esposito
- Computational Genomics Laboratory, Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
| | - Nicolò Gualandi
- Computational Genomics Laboratory, Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
| | - Giovanni Spirito
- Computational Genomics Laboratory, Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
- CMP3vda, via Lavoratori Vittime del Col Du Mont 28, 11100 Aosta, Italy
| | - Federico Ansaloni
- Computational Genomics Laboratory, Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia, 16132 Genova, Italy
| | - Stefano Gustincich
- CMP3vda, via Lavoratori Vittime del Col Du Mont 28, 11100 Aosta, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia, 16132 Genova, Italy
| | - Remo Sanges
- Computational Genomics Laboratory, Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
- Central RNA Laboratory, Istituto Italiano di Tecnologia, 16132 Genova, Italy
- Correspondence:
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21
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Bajus M, Macko-Podgórni A, Grzebelus D, Baránek M. A review of strategies used to identify transposition events in plant genomes. FRONTIERS IN PLANT SCIENCE 2022; 13:1080993. [PMID: 36531345 PMCID: PMC9751208 DOI: 10.3389/fpls.2022.1080993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
Transposable elements (TEs) were initially considered redundant and dubbed 'junk DNA'. However, more recently they were recognized as an essential element of genome plasticity. In nature, they frequently become active upon exposition of the host to stress conditions. Even though most transposition events are neutral or even deleterious, occasionally they may happen to be beneficial, resulting in genetic novelty providing better fitness to the host. Hence, TE mobilization may promote adaptability and, in the long run, act as a significant evolutionary force. There are many examples of TE insertions resulting in increased tolerance to stresses or in novel features of crops which are appealing to the consumer. Possibly, TE-driven de novo variability could be utilized for crop improvement. However, in order to systematically study the mechanisms of TE/host interactions, it is necessary to have suitable tools to globally monitor any ongoing TE mobilization. With the development of novel potent technologies, new high-throughput strategies for studying TE dynamics are emerging. Here, we present currently available methods applied to monitor the activity of TEs in plants. We divide them on the basis of their operational principles, the position of target molecules in the process of transposition and their ability to capture real cases of actively transposing elements. Their possible theoretical and practical drawbacks are also discussed. Finally, conceivable strategies and combinations of methods resulting in an improved performance are proposed.
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Affiliation(s)
- Marko Bajus
- Mendeleum—Institute of Genetics, Faculty of Horticulture, Mendel University in Brno, Lednice, Czechia
| | - Alicja Macko-Podgórni
- Department of Plant Biology and Biotechnology, Faculty of Biotechnology and Horticulture, University of Agriculture in Krakow, Kraków, Poland
| | - Dariusz Grzebelus
- Department of Plant Biology and Biotechnology, Faculty of Biotechnology and Horticulture, University of Agriculture in Krakow, Kraków, Poland
| | - Miroslav Baránek
- Mendeleum—Institute of Genetics, Faculty of Horticulture, Mendel University in Brno, Lednice, Czechia
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22
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Savytska N, Heutink P, Bansal V. Transcription start site signal profiling improves transposable element RNA expression analysis at locus-level. Front Genet 2022; 13:1026847. [PMID: 36338986 PMCID: PMC9633680 DOI: 10.3389/fgene.2022.1026847] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/11/2022] [Indexed: 08/31/2023] Open
Abstract
The transcriptional activity of Transposable Elements (TEs) has been involved in numerous pathological processes, including neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration. The TE expression analysis from short-read sequencing technologies is, however, challenging due to the multitude of similar sequences derived from singular TEs subfamilies and the exaptation of TEs within longer coding or non-coding RNAs. Specialised tools have been developed to quantify the expression of TEs that either relies on probabilistic re-distribution of multimapper count fractions or allow for discarding multimappers altogether. Until now, the benchmarking across those tools was largely limited to aggregated expression estimates over whole TEs subfamilies. Here, we compared the performance of recently published tools (SQuIRE, TElocal, SalmonTE) with simplistic quantification strategies (featureCounts in unique, fraction and random modes) at the individual loci level. Using simulated datasets, we examined the false discovery rate and the primary driver of those false positive hits in the optimal quantification strategy. Our findings suggest a high false discovery number that exceeds the total number of correctly recovered active loci for all the quantification strategies, including the best performing tool TElocal. As a remedy, filtering based on the minimum number of read counts or baseMean expression improves the F1 score and decreases the number of false positives. Finally, we demonstrate that additional profiling of Transcription Start Site mapping statistics (using a k-means clustering approach) significantly improves the performance of TElocal while reporting a reliable set of detected and differentially expressed TEs in human simulated RNA-seq data.
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Affiliation(s)
| | | | - Vikas Bansal
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
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23
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Stow EC, Baddoo M, LaRosa AJ, LaCoste D, Deininger P, Belancio V. SCIFER: approach for analysis of LINE-1 mRNA expression in single cells at a single locus resolution. Mob DNA 2022; 13:21. [PMID: 36028901 PMCID: PMC9413895 DOI: 10.1186/s13100-022-00276-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 08/09/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Endogenous expression of L1 mRNA is the first step in an L1-initiated mutagenesis event. However, the contribution of individual cell types to patterns of organ-specific L1 mRNA expression remains poorly understood, especially at single-locus resolution. We introduce a method to quantify expression of mobile elements at the single-locus resolution in scRNA-Seq datasets called Single Cell Implementation to Find Expressed Retrotransposons (SCIFER). SCIFER aligns scRNA-Seq reads uniquely to the genome and extracts alignments from single cells by cell-specific barcodes. In contrast to the alignment performed using default parameters, this alignment strategy increases accuracy of L1 locus identification by retaining only reads that are uniquely mapped to individual L1 loci. L1 loci expressed in single cells are unambiguously identified using a list of L1 loci manually validated to be expressed in bulk RNA-Seq datasets generated from the same cell line or organ. RESULTS Validation of SCIFER using MCF7 cells determined technical parameters needed for optimal detection of L1 expression in single cells. We show that unsupervised analysis of L1 expression in single cells exponentially inflates both the levels of L1 expression and the number of expressed L1 loci. Application of SCIFER to analysis of scRNA-Seq datasets generated from mouse and human testes identified that mouse Round Spermatids and human Spermatogonia, Spermatocytes, and Round Spermatids express the highest levels of L1 mRNA. Our analysis also determined that similar to mice, human testes from unrelated individuals share as much as 80% of expressed L1 loci. Additionally, SCIFER determined that individual mouse cells co-express different L1 sub-families and different families of transposable elements, experimentally validating their co-existence in the same cell. CONCLUSIONS SCIFER detects mRNA expression of individual L1 loci in single cells. It is compatible with scRNA-Seq datasets prepared using traditional sequencing methods. Validated using a human cancer cell line, SCIFER analysis of mouse and human testes identified key cell types supporting L1 expression in these species. This will further our understanding of differences and similarities in endogenous L1 mRNA expression patterns in mice and humans.
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Affiliation(s)
- 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
| | - Melody Baddoo
- 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
| | - Alexis J LaRosa
- 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
| | - 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 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.
- Department of Epidemiology, Tulane School of Public Health and Tropical Medicine, New Orleans, LA, 70112, USA.
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24
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Ansaloni F, Gualandi N, Esposito M, Gustincich S, Sanges R. TEspeX: consensus-specific quantification of transposable element expression preventing biases from exonized fragments. Bioinformatics 2022; 38:4430-4433. [PMID: 35876845 PMCID: PMC9477521 DOI: 10.1093/bioinformatics/btac526] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 07/08/2022] [Accepted: 07/12/2022] [Indexed: 12/24/2022] Open
Abstract
SUMMARY Transposable elements (TEs) play key roles in crucial biological pathways. Therefore, several tools enabling the quantification of their expression were recently developed. However, many of the existing tools lack the capability to distinguish between the transcription of autonomously expressed TEs and TE fragments embedded in canonical coding/non-coding non-TE transcripts. Consequently, an apparent change in the expression of a given TE may simply reflect the variation in the expression of the transcripts containing TE-derived sequences. To overcome this issue, we have developed TEspeX, a pipeline for the quantification of TE expression at the consensus level. TEspeX uses Illumina RNA-seq short reads to quantify TE expression avoiding counting reads deriving from inactive TE fragments embedded in canonical transcripts. AVAILABILITY AND IMPLEMENTATION The tool is implemented in python3, distributed under the GNU General Public License (GPL) and available on Github at https://github.com/fansalon/TEspeX (Zenodo URL: https://doi.org/10.5281/zenodo.6800331). SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Federico Ansaloni
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste 34136, Italy,Central RNA Laboratory, Istituto Italiano di Tecnologia, Genova 16163, Italy
| | - Nicolò Gualandi
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste 34136, Italy
| | - Mauro Esposito
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste 34136, Italy
| | | | - Remo Sanges
- To whom correspondence should be addressed. or
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25
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A retrotransposon storm marks clinical phenoconversion to late-onset Alzheimer's disease. GeroScience 2022; 44:1525-1550. [PMID: 35585302 PMCID: PMC9213607 DOI: 10.1007/s11357-022-00580-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 04/26/2022] [Indexed: 12/03/2022] Open
Abstract
Recent reports have suggested that the reactivation of otherwise transcriptionally silent transposable elements (TEs) might induce brain degeneration, either by dysregulating the expression of genes and pathways implicated in cognitive decline and dementia or through the induction of immune-mediated neuroinflammation resulting in the elimination of neural and glial cells. In the work we present here, we test the hypothesis that differentially expressed TEs in blood could be used as biomarkers of cognitive decline and development of AD. To this aim, we used a sample of aging subjects (age > 70) that developed late-onset Alzheimer’s disease (LOAD) over a relatively short period of time (12–48 months), for which blood was available before and after their phenoconversion, and a group of cognitive stable subjects as controls. We applied our developed and validated customized pipeline that allows the identification, characterization, and quantification of the differentially expressed (DE) TEs before and after the onset of manifest LOAD, through analyses of RNA-Seq data. We compared the level of DE TEs within more than 600,000 TE-mapping RNA transcripts from 25 individuals, whose specimens we obtained before and after their phenotypic conversion (phenoconversion) to LOAD, and discovered that 1790 TE transcripts showed significant expression differences between these two timepoints (logFC ± 1.5, logCMP > 5.3, nominal p value < 0.01). These DE transcripts mapped both over- and under-expressed TE elements. Occurring before the clinical phenoconversion, this TE storm features significant increases in DE transcripts of LINEs, LTRs, and SVAs, while those for SINEs are significantly depleted. These dysregulations end with signs of manifest LOAD. This set of highly DE transcripts generates a TE transcriptional profile that accurately discriminates the before and after phenoconversion states of these subjects. Our findings suggest that a storm of DE TEs occurs before phenoconversion from normal cognition to manifest LOAD in risk individuals compared to controls, and may provide useful blood-based biomarkers for heralding such a clinical transition, also suggesting that TEs can indeed participate in the complex process of neurodegeneration.
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26
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Taylor D, Lowe R, Philippe C, Cheng KCL, Grant OA, Zabet NR, Cristofari G, Branco MR. Locus-specific chromatin profiling of evolutionarily young transposable elements. Nucleic Acids Res 2022; 50:e33. [PMID: 34908129 PMCID: PMC8989514 DOI: 10.1093/nar/gkab1232] [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: 09/06/2021] [Revised: 11/15/2021] [Accepted: 12/02/2021] [Indexed: 01/13/2023] Open
Abstract
Despite a vast expansion in the availability of epigenomic data, our knowledge of the chromatin landscape at interspersed repeats remains highly limited by difficulties in mapping short-read sequencing data to these regions. In particular, little is known about the locus-specific regulation of evolutionarily young transposable elements (TEs), which have been implicated in genome stability, gene regulation and innate immunity in a variety of developmental and disease contexts. Here we propose an approach for generating locus-specific protein-DNA binding profiles at interspersed repeats, which leverages information on the spatial proximity between repetitive and non-repetitive genomic regions. We demonstrate that the combination of HiChIP and a newly developed mapping tool (PAtChER) yields accurate protein enrichment profiles at individual repetitive loci. Using this approach, we reveal previously unappreciated variation in the epigenetic profiles of young TE loci in mouse and human cells. Insights gained using our method will be invaluable for dissecting the molecular determinants of TE regulation and their impact on the genome.
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Affiliation(s)
- Darren Taylor
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London E1 2AT, UK
| | - Robert Lowe
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London E1 2AT, UK
| | | | - Kevin C L Cheng
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London E1 2AT, UK
| | - Olivia A Grant
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London E1 2AT, UK
- School of Life Sciences, University of Essex, Colchester, CO4 3SQ, UK
| | - Nicolae Radu Zabet
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London E1 2AT, UK
| | | | - Miguel R Branco
- Blizard Institute, Barts and The London School of Medicine and Dentistry, QMUL, London E1 2AT, UK
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27
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Berrens RV, Yang A, Laumer CE, Lun ATL, Bieberich F, Law CT, Lan G, Imaz M, Bowness JS, Brockdorff N, Gaffney DJ, Marioni JC. Locus-specific expression of transposable elements in single cells with CELLO-seq. Nat Biotechnol 2022; 40:546-554. [PMID: 34782740 PMCID: PMC7614850 DOI: 10.1038/s41587-021-01093-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 09/13/2021] [Indexed: 02/07/2023]
Abstract
Transposable elements (TEs) regulate diverse biological processes, from early development to cancer. Expression of young TEs is difficult to measure with next-generation, single-cell sequencing technologies because their highly repetitive nature means that short complementary DNA reads cannot be unambiguously mapped to a specific locus. Single CELl LOng-read RNA-sequencing (CELLO-seq) combines long-read single cell RNA-sequencing with computational analyses to measure TE expression at unique loci. We used CELLO-seq to assess the widespread expression of TEs in two-cell mouse blastomeres as well as in human induced pluripotent stem cells. Across both species, old and young TEs showed evidence of locus-specific expression with simulations demonstrating that only a small number of very young elements in the mouse could not be mapped back to the reference with high confidence. Exploring the relationship between the expression of individual elements and putative regulators revealed large heterogeneity, with TEs within a class showing different patterns of correlation and suggesting distinct regulatory mechanisms.
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Affiliation(s)
- Rebecca V Berrens
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK.
- Developmental Epigenetics, Department of Biochemistry, University of Oxford, Oxford, UK.
| | - Andrian Yang
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, UK
| | - Christopher E Laumer
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, UK
| | - Aaron T L Lun
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
- Genentech, South San Francisco, CA, USA
| | - Florian Bieberich
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
- ETH Zürich, Basel, Switzerland
| | - Cheuk-Ting Law
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
- Department of Pathology, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Guocheng Lan
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
- School of Biomedical Sciences,Stem Cell and Regenerative Consortium, Centre for PanorOmic Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Maria Imaz
- Wellcome Sanger Institute, Cambridge, UK
- Division of Cardiovascular Medicine, University of Cambridge, Cambridge, UK
| | - Joseph S Bowness
- Developmental Epigenetics, Department of Biochemistry, University of Oxford, Oxford, UK
| | - Neil Brockdorff
- Developmental Epigenetics, Department of Biochemistry, University of Oxford, Oxford, UK
| | - Daniel J Gaffney
- Wellcome Sanger Institute, Cambridge, UK
- Genomics Plc, Oxford, UK
| | - John C Marioni
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK.
- European Molecular Biology Laboratory, European Bioinformatics Institute, Cambridge, UK.
- Wellcome Sanger Institute, Cambridge, UK.
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28
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Pfaff AL, Bubb VJ, Quinn JP, Koks S. Locus specific reduction of L1 expression in the cortices of individuals with amyotrophic lateral sclerosis. Mol Brain 2022; 15:25. [PMID: 35346298 PMCID: PMC8961898 DOI: 10.1186/s13041-022-00914-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 03/21/2022] [Indexed: 11/16/2022] Open
Abstract
The activation and dysregulation of retrotransposons has been identified in the CNS of individuals with the fatal neurodegenerative disorder Amyotrophic lateral sclerosis (ALS). This includes elements from multiple different families and subfamilies of retrotransposons, however there is limited knowledge of the specific loci from which this expression occurs in ALS. The long interspersed element-1 (L1) is the only autonomous retrotransposon in the human genome and members of this family of elements maintain the ability to mobilise. Despite L1s contributing to 17% of the human genome only 80-100 L1s encode the required proteins for mobilisation and are retrotransposition competent. Identifying the specific loci from which L1 expression occurs will inform on the potential functional consequences of their expression, such as the potential for somatic retrotransposition or DNA damage caused by the endonuclease activity of the ORF2 protein of the L1. Here we characterised L1 loci expression using the L1EM tool ( https://github.com/FenyoLab/L1EM ) in RNA sequencing data from 518 samples across four tissues (motor cortex, frontal cortex, cerebellum and cervical spinal cord) in the Target ALS cohort obtained from the New York Genome Center. There was a significant reduction in total intact L1 expression (those that encode functional proteins) in two brain regions of individuals with ALS compared to controls and clustering of the ALS brain regions occurred based on their intact L1 expression profile. Although overall the levels of L1 expression were reduced in ALS/ALS with other neurological disorder (ND) there were individuals in which L1s were expressed at much higher levels than the rest of the ALS/ALSND cohort. Expressed L1 loci were more frequently located in introns compared to those not expressed and the level of L1 expression positively correlated with the expression of the gene in which it was located. Significant differences were observed in the expression profiles of L1s in ALS and specific features of these elements, such as location in the genome and whether or not they are intact, were significantly associated with those that were expressed in the cohort.
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Affiliation(s)
- Abigail L. Pfaff
- Perron Institute for Neurological and Translational Science, Perth, 8 Verdun Street, Nedlands, WA 6009 Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA Australia
| | - Vivien J. Bubb
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - John P. Quinn
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Sulev Koks
- Perron Institute for Neurological and Translational Science, Perth, 8 Verdun Street, Nedlands, WA 6009 Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, WA Australia
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29
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Creamer KM, Larsen EC, Lawrence JB. ZNF146/OZF and ZNF507 target LINE-1 sequences. G3 (BETHESDA, MD.) 2022; 12:jkac002. [PMID: 35100360 PMCID: PMC8896011 DOI: 10.1093/g3journal/jkac002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 12/03/2021] [Indexed: 06/14/2023]
Abstract
Repetitive sequences including transposable elements and transposon-derived fragments account for nearly half of the human genome. While transposition-competent transposable elements must be repressed to maintain genomic stability, mutated and fragmented transposable elements comprising the bulk of repetitive sequences can also contribute to regulation of host gene expression and broader genome organization. Here, we analyzed published ChIP-seq data sets to identify proteins broadly enriched on transposable elements in the human genome. We show 2 of the proteins identified, C2H2 zinc finger-containing proteins ZNF146 (also known as OZF) and ZNF507, are targeted to distinct sites within LINE-1 ORF2 at thousands of locations in the genome. ZNF146 binding sites are found at old and young LINE-1 elements. In contrast, ZNF507 preferentially binds at young LINE-1 sequences correlated to sequence changes in LINE-1 elements at ZNF507's binding site. To gain further insight into ZNF146 and ZNF507 function, we disrupt their expression in HEK293 cells using CRISPR/Cas9 and perform RNA sequencing, finding modest gene expression changes in cells where ZNF507 has been disrupted. We further identify a physical interaction between ZNF507 and PRMT5, suggesting ZNF507 may target arginine methylation activity to LINE-1 sequences.
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Affiliation(s)
- Kevin M Creamer
- Department of Neurology and Pediatrics, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Eric C Larsen
- Department of Neurology and Pediatrics, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jeanne B Lawrence
- Department of Neurology and Pediatrics, University of Massachusetts Medical School, Worcester, MA 01655, USA
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30
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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: 8] [Impact Index Per Article: 4.0] [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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31
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Hutt KJ, Lim SL, Zhang QH, Gonzalez M, O'Connor AE, Merriner DJ, Liew SH, Al-Zubaidi U, Yuen WS, Adhikari D, Robker RL, Mann JR, Carroll J, O'Bryan MK. HENMT1 is involved in the maintenance of normal female fertility in the mouse. Mol Hum Reprod 2021; 27:6378251. [PMID: 34590701 DOI: 10.1093/molehr/gaab061] [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: 12/07/2020] [Revised: 07/07/2021] [Indexed: 11/12/2022] Open
Abstract
PIWI-interacting small RNAs (piRNAs) maintain genome stability in animal germ cells, with a predominant role in silencing transposable elements. Mutations in the piRNA pathway in the mouse uniformly lead to failed spermatogenesis and male sterility. By contrast, mutant females are fertile. In keeping with this paradigm, we previously reported male sterility and female fertility associated with loss of the enzyme HENMT1, which is responsible for stabilising piRNAs through the catalysation of 3'-terminal 2'-O-methylation. However, the Henmt1 mutant females were poor breeders, suggesting they could be subfertile. Therefore, we investigated oogenesis and female fertility in these mice in greater detail. Here, we show that mutant females indeed have a 3- to 4-fold reduction in follicle number and reduced litter sizes. In addition, meiosis-II mutant oocytes display various spindle abnormalities and have a dramatically altered transcriptome which includes a down-regulation of transcripts required for microtubule function. This down-regulation could explain the spindle defects observed with consequent reductions in litter size. We suggest these various effects on oogenesis could be exacerbated by asynapsis, an apparently universal feature of piRNA mutants of both sexes. Our findings reveal that loss of the piRNA pathway in females has significant functional consequences.
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Affiliation(s)
- Karla J Hutt
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Shu Ly Lim
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Qing-Hua Zhang
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Maria Gonzalez
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Anne E O'Connor
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia.,School of Biological Sciences, Monash University, Victoria, Australia
| | - D Jo Merriner
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia.,School of Biological Sciences, Monash University, Victoria, Australia
| | - Seng H Liew
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Usama Al-Zubaidi
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia.,Applied Embryology Department, High Institute for Infertility Diagnosis and Assisted Reproductive Technologies, Al-Nahrain University, Baghdad, Iraq
| | - Wai Shan Yuen
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Deepak Adhikari
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Rebecca L Robker
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia.,Robinson Research Institute, School of Medicine, The University of Adelaide, South Australia, Australia
| | - Jeffrey R Mann
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - John Carroll
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Moira K O'Bryan
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia.,School of Biological Sciences, Monash University, Victoria, Australia
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32
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The Dynamism of Transposon Methylation for Plant Development and Stress Adaptation. Int J Mol Sci 2021; 22:ijms222111387. [PMID: 34768817 PMCID: PMC8583499 DOI: 10.3390/ijms222111387] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/13/2021] [Accepted: 10/19/2021] [Indexed: 02/06/2023] Open
Abstract
Plant development processes are regulated by epigenetic alterations that shape nuclear structure, gene expression, and phenotypic plasticity; these alterations can provide the plant with protection from environmental stresses. During plant growth and development, these processes play a significant role in regulating gene expression to remodel chromatin structure. These epigenetic alterations are mainly regulated by transposable elements (TEs) whose abundance in plant genomes results in their interaction with genomes. Thus, TEs are the main source of epigenetic changes and form a substantial part of the plant genome. Furthermore, TEs can be activated under stress conditions, and activated elements cause mutagenic effects and substantial genetic variability. This introduces novel gene functions and structural variation in the insertion sites and primarily contributes to epigenetic modifications. Altogether, these modifications indirectly or directly provide the ability to withstand environmental stresses. In recent years, many studies have shown that TE methylation plays a major role in the evolution of the plant genome through epigenetic process that regulate gene imprinting, thereby upholding genome stability. The induced genetic rearrangements and insertions of mobile genetic elements in regions of active euchromatin contribute to genome alteration, leading to genomic stress. These TE-mediated epigenetic modifications lead to phenotypic diversity, genetic variation, and environmental stress tolerance. Thus, TE methylation is essential for plant evolution and stress adaptation, and TEs hold a relevant military position in the plant genome. High-throughput techniques have greatly advanced the understanding of TE-mediated gene expression and its associations with genome methylation and suggest that controlled mobilization of TEs could be used for crop breeding. However, development application in this area has been limited, and an integrated view of TE function and subsequent processes is lacking. In this review, we explore the enormous diversity and likely functions of the TE repertoire in adaptive evolution and discuss some recent examples of how TEs impact gene expression in plant development and stress adaptation.
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33
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Ravel-Godreuil C, Znaidi R, Bonnifet T, Joshi RL, Fuchs J. Transposable elements as new players in neurodegenerative diseases. FEBS Lett 2021; 595:2733-2755. [PMID: 34626428 DOI: 10.1002/1873-3468.14205] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/23/2021] [Accepted: 10/03/2021] [Indexed: 01/02/2023]
Abstract
Neurodegenerative diseases (NDs), including the most prevalent Alzheimer's disease and Parkinson disease, share common pathological features. Despite decades of gene-centric approaches, the molecular mechanisms underlying these diseases remain widely elusive. In recent years, transposable elements (TEs), long considered 'junk' DNA, have gained growing interest as pathogenic players in NDs. Age is the major risk factor for most NDs, and several repressive mechanisms of TEs, such as heterochromatinization, fail with age. Indeed, heterochromatin relaxation leading to TE derepression has been reported in various models of neurodegeneration and NDs. There is also evidence that certain pathogenic proteins involved in NDs (e.g., tau, TDP-43) may control the expression of TEs. The deleterious consequences of TE activation are not well known but they could include DNA damage and genomic instability, altered host gene expression, and/or neuroinflammation, which are common hallmarks of neurodegeneration and aging. TEs might thus represent an overlooked pathogenic culprit for both brain aging and neurodegeneration. Certain pathological effects of TEs might be prevented by inhibiting their activity, pointing to TEs as novel targets for neuroprotection.
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Affiliation(s)
- Camille Ravel-Godreuil
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Rania Znaidi
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Tom Bonnifet
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Rajiv L Joshi
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Julia Fuchs
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
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Pasquesi GIM, Perry BW, Vandewege MW, Ruggiero RP, Schield DR, Castoe TA. Vertebrate Lineages Exhibit Diverse Patterns of Transposable Element Regulation and Expression across Tissues. Genome Biol Evol 2021; 12:506-521. [PMID: 32271917 PMCID: PMC7211425 DOI: 10.1093/gbe/evaa068] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2020] [Indexed: 12/11/2022] Open
Abstract
Transposable elements (TEs) comprise a major fraction of vertebrate genomes, yet little is known about their expression and regulation across tissues, and how this varies across major vertebrate lineages. We present the first comparative analysis integrating TE expression and TE regulatory pathway activity in somatic and gametic tissues for a diverse set of 12 vertebrates. We conduct simultaneous gene and TE expression analyses to characterize patterns of TE expression and TE regulation across vertebrates and examine relationships between these features. We find remarkable variation in the expression of genes involved in TE negative regulation across tissues and species, yet consistently high expression in germline tissues, particularly in testes. Most vertebrates show comparably high levels of TE regulatory pathway activity across gonadal tissues except for mammals, where reduced activity of TE regulatory pathways in ovarian tissues may be the result of lower relative germ cell densities. We also find that all vertebrate lineages examined exhibit remarkably high levels of TE-derived transcripts in somatic and gametic tissues, with recently active TE families showing higher expression in gametic tissues. Although most TE-derived transcripts originate from inactive ancient TE families (and are likely incapable of transposition), such high levels of TE-derived RNA in the cytoplasm may have secondary, unappreciated biological relevance.
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Affiliation(s)
- Giulia I M Pasquesi
- Department of Biology, University of Texas at Arlington.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington
| | | | | | - Drew R Schield
- Department of Biology, University of Texas at Arlington.,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington
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35
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Stow EC, Kaul T, deHaro DL, Dem MR, Beletsky AG, Morales ME, Du Q, LaRosa AJ, Yang H, Smither E, Baddoo M, Ungerleider N, Deininger P, Belancio VP. Organ-, sex- and age-dependent patterns of endogenous L1 mRNA expression at a single locus resolution. Nucleic Acids Res 2021; 49:5813-5831. [PMID: 34023901 PMCID: PMC8191783 DOI: 10.1093/nar/gkab369] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 04/21/2021] [Accepted: 04/28/2021] [Indexed: 11/13/2022] Open
Abstract
Expression of L1 mRNA, the first step in the L1 copy-and-paste amplification cycle, is a prerequisite for L1-associated genomic instability. We used a reported stringent bioinformatics method to parse L1 mRNA transcripts and measure the level of L1 mRNA expressed in mouse and rat organs at a locus-specific resolution. This analysis determined that mRNA expression of L1 loci in rodents exhibits striking organ specificity with less than 0.8% of loci shared between organs of the same organism. This organ specificity in L1 mRNA expression is preserved in male and female mice and across age groups. We discovered notable differences in L1 mRNA expression between sexes with only 5% of expressed L1 loci shared between male and female mice. Moreover, we report that the levels of total L1 mRNA expression and the number and spectrum of expressed L1 loci fluctuate with age as independent variables, demonstrating different patterns in different organs and sexes. Overall, our comparisons between organs and sexes and across ages ranging from 2 to 22 months establish previously unforeseen dynamic changes in L1 mRNA expression in vivo. These findings establish the beginning of an atlas of endogenous L1 mRNA expression across a broad range of biological variables that will guide future studies.
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Affiliation(s)
- 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, LA 70112 USA
| | - Tiffany Kaul
- 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
| | - Dawn L deHaro
- 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, LA 70112 USA
| | - Madeleine R Dem
- 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, LA 70112 USA
| | - Anna G Beletsky
- 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, LA 70112 USA
| | - Maria E Morales
- 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
| | - 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, LA 70112 USA
| | - Alexis J LaRosa
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans, LA 70112 USA
| | - Hanlin Yang
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
| | - Emily Smither
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans, LA 70112 USA
| | - Melody Baddoo
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
| | - Nathan Ungerleider
- 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
- 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, LA 70112 USA
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36
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Rostami MR, Bradic M. The derepression of transposable elements in lung cells is associated with the inflammatory response and gene activation in idiopathic pulmonary fibrosis. Mob DNA 2021; 12:14. [PMID: 34108012 PMCID: PMC8191028 DOI: 10.1186/s13100-021-00241-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 04/26/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Transposable elements (TEs) are repetitive sequences of viral origin that compose almost half of the human genome. These elements are tightly controlled within cells, and if activated, they can cause changes in both gene regulation and immune viral responses that have been associated with several chronic inflammatory diseases in humans. As oxidants are potent activators of TEs, and because oxidative injury is a major risk factor in relation to idiopathic pulmonary fibrosis (IPF), we hypothesized that TEs might be involved in the regulation of gene expression and so contribute to inflammation in cases of IPF. IPF is a fatal lung disease that involves the gradual replacement of the alveolar tissue with fibrotic scars as well as the accumulation of inflammatory cells in the lower respiratory tract. Although IPF is known to occur as a result of the complex interaction between age, environmental risk factors (i.e., oxidative stress) and genetics, the relative contributions of these factors to the disease remain unclear. To determine whether TEs are associated with IPF, we compared the transcriptional profiles of the genes and TEs of lung cells obtained from both healthy donors and IPF patients. RESULTS We quantified TE and gene expression levels using a published bulk RNA-seq dataset containing 24 subjects (16 donors and eight IPF patients), including three lung-cell types per subject, as well as an scRNA-seq dataset concerning 16 subjects (eight donors and eight IPF patients). We found evidence of TE dysregulation in the alveolar type II lung cells and alveolar macrophages of the IPF patients. In addition, the activation of the LINE1 family of elements in IPF is associated with the increased expression of TE cellular regulators (MOV10, IFI16, SAMHD1, and APOBECG3), interferon-stimulating genes (ISG15, IFI6, IFI27, IFI44, and OAS1), chemokines (CX3CL1 and CXCL9), and interleukins (IL15RA). We also propose that TE derepression might be involved in the regulation of previously reported IPF candidate genes (MUC5B, CHL1, SPP1, and MMP7). CONCLUSION Based on our findings, we propose that TE derepression plays an important role in the regulation of gene expression and can also prompt both the recruitment of inflammatory processes and the disruption of the immunological balance, which can lead to chronic inflammation in IPF.
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Affiliation(s)
- Mahboubeh R Rostami
- Department of Genetic Medicine, Weill Cornell Medical College, 1300 York Avenue, Box 164, New York, NY, 10065, USA
| | - Martina Bradic
- Department of Genetic Medicine, Weill Cornell Medical College, 1300 York Avenue, Box 164, New York, NY, 10065, USA.
- Marie-Josee and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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37
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Siudeja K, van den Beek M, Riddiford N, Boumard B, Wurmser A, Stefanutti M, Lameiras S, Bardin AJ. Unraveling the features of somatic transposition in the Drosophila intestine. EMBO J 2021; 40:e106388. [PMID: 33634906 PMCID: PMC8090852 DOI: 10.15252/embj.2020106388] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 01/20/2021] [Accepted: 01/27/2021] [Indexed: 12/22/2022] Open
Abstract
Transposable elements (TEs) play a significant role in evolution, contributing to genetic variation. However, TE mobilization in somatic cells is not well understood. Here, we address the prevalence of transposition in a somatic tissue, exploiting the Drosophila midgut as a model. Using whole-genome sequencing of in vivo clonally expanded gut tissue, we have mapped hundreds of high-confidence somatic TE integration sites genome-wide. We show that somatic retrotransposon insertions are associated with inactivation of the tumor suppressor Notch, likely contributing to neoplasia formation. Moreover, applying Oxford Nanopore long-read sequencing technology we provide evidence for tissue-specific differences in retrotransposition. Comparing somatic TE insertional activity with transcriptomic and small RNA sequencing data, we demonstrate that transposon mobility cannot be simply predicted by whole tissue TE expression levels or by small RNA pathway activity. Finally, we reveal that somatic TE insertions in the adult fly intestine are enriched in genic regions and in transcriptionally active chromatin. Together, our findings provide clear evidence of ongoing somatic transposition in Drosophila and delineate previously unknown features underlying somatic TE mobility in vivo.
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Affiliation(s)
- Katarzyna Siudeja
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Marius van den Beek
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Nick Riddiford
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Benjamin Boumard
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Annabelle Wurmser
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Marine Stefanutti
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
| | - Sonia Lameiras
- ICGex Next‐Generation Sequencing PlatformInstitut CuriePSL Research UniversityParisFrance
| | - Allison J Bardin
- Institut CurieCNRSUMR 3215INSERM U934Stem Cells and Tissue Homeostasis GroupPSL Research UniversityParisFrance
- Sorbonne UniversitésUPMC Univ Paris 6ParisFrance
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38
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Liu L, Wang H, Xu GL, Liu L. Tet1 Deficiency Leads to Premature Ovarian Failure. Front Cell Dev Biol 2021; 9:644135. [PMID: 33834024 PMCID: PMC8021788 DOI: 10.3389/fcell.2021.644135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 02/26/2021] [Indexed: 11/13/2022] Open
Abstract
Tet enzymes participate in DNA demethylation and play critical roles in stem cell pluripotency and differentiation. DNA methylation alters with age. We find that Tet1 deficiency reduces fertility and leads to accelerated reproductive failure with age. Noticeably, Tet1-deficient mice at young age exhibit dramatically reduced follicle reserve and the follicle reserve further decreases with age, phenomenon consistent with premature ovarian failure (POF) syndrome. Consequently, Tet1-deficient mice become infertile by reproductive middle age, while age matched wild-type mice still robustly reproduce. Moreover, by single cell transcriptome analysis of oocytes, Tet1 deficiency elevates organelle fission, associated with defects in ubiquitination and declined autophagy, and also upregulates signaling pathways for Alzheimer's diseases, but down-regulates X-chromosome linked genes, such as Fmr1, which is known to be implicated in POF. Additionally, Line1 is aberrantly upregulated and endogenous retroviruses also are altered in Tet1-deficient oocytes. These molecular changes are consistent with oocyte senescence and follicle atresia and depletion found in premature ovarian failure or insufficiency. Our data suggest that Tet1 enzyme plays roles in maintaining oocyte quality as well as oocyte number and follicle reserve and its deficiency can lead to POF.
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Affiliation(s)
- Linlin Liu
- Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin, China.,State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Huasong Wang
- Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin, China.,State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Guo Liang Xu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China.,Key Laboratory of Medical Epigenetics and Metabolism, Institutes of Biomedical Sciences, Medical College of Fudan University, Shanghai, China
| | - Lin Liu
- Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin, China.,State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
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39
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Roller M, Stamper E, Villar D, Izuogu O, Martin F, Redmond AM, Ramachanderan R, Harewood L, Odom DT, Flicek P. LINE retrotransposons characterize mammalian tissue-specific and evolutionarily dynamic regulatory regions. Genome Biol 2021; 22:62. [PMID: 33602314 PMCID: PMC7890895 DOI: 10.1186/s13059-021-02260-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 01/04/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND To investigate the mechanisms driving regulatory evolution across tissues, we experimentally mapped promoters, enhancers, and gene expression in the liver, brain, muscle, and testis from ten diverse mammals. RESULTS The regulatory landscape around genes included both tissue-shared and tissue-specific regulatory regions, where tissue-specific promoters and enhancers evolved most rapidly. Genomic regions switching between promoters and enhancers were more common across species, and less common across tissues within a single species. Long Interspersed Nuclear Elements (LINEs) played recurrent evolutionary roles: LINE L1s were associated with tissue-specific regulatory regions, whereas more ancient LINE L2s were associated with tissue-shared regulatory regions and with those switching between promoter and enhancer signatures across species. CONCLUSIONS Our analyses of the tissue-specificity and evolutionary stability among promoters and enhancers reveal how specific LINE families have helped shape the dynamic mammalian regulome.
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Affiliation(s)
- Maša Roller
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Ericca Stamper
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
- Cancer Research UK Cambridge Institute, University of Cambridge, Robinson Way, Cambridge, CB2 0RE, UK
- Present address: Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL, 33458, USA
| | - Diego Villar
- Cancer Research UK Cambridge Institute, University of Cambridge, Robinson Way, Cambridge, CB2 0RE, UK
- Present address: Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK
| | - Osagie Izuogu
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Fergal Martin
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Aisling M Redmond
- Cancer Research UK Cambridge Institute, University of Cambridge, Robinson Way, Cambridge, CB2 0RE, UK
- Present address: MRC Cancer Unit, Hutchison-MRC Research Centre, University of Cambridge, Cambridge, CB2 0XZ, UK
| | - Raghavendra Ramachanderan
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK
| | - Louise Harewood
- Cancer Research UK Cambridge Institute, University of Cambridge, Robinson Way, Cambridge, CB2 0RE, UK
- Present address: Precision Medicine Centre of Excellence, Queen's University Belfast, Belfast, BT9 7AE, UK
| | - Duncan T Odom
- Cancer Research UK Cambridge Institute, University of Cambridge, Robinson Way, Cambridge, CB2 0RE, UK.
- German Cancer Research Center (DKFZ), Division of Regulatory Genomics and Cancer Evolution, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.
| | - Paul Flicek
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK.
- Cancer Research UK Cambridge Institute, University of Cambridge, Robinson Way, Cambridge, CB2 0RE, UK.
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK.
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40
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Kaur D, Agrahari M, Singh SS, Mandal PK, Bhattacharya A, Bhattacharya S. Transcriptomic analysis of Entamoeba histolytica reveals domain-specific sense strand expression of LINE-encoded ORFs with massive antisense expression of RT domain. Plasmid 2021; 114:102560. [PMID: 33482228 DOI: 10.1016/j.plasmid.2021.102560] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/29/2020] [Accepted: 12/31/2020] [Indexed: 11/29/2022]
Abstract
LINEs are retrotransposable elements found in diverse organisms. Their activity is kept in check by several mechanisms, including transcriptional silencing. Here we have analyzed the transcription status of LINE1 copies in the early-branching parasitic protist Entamoeba histolytica. Full-length EhLINE1 encodes ORF1, and ORF2 with reverse transcriptase (RT) and endonuclease (EN) domains. RNA-Seq analysis of EhLINE1 copies (both truncated and full-length) showed unique features. Firstly, although 20/41 transcribed copies were full-length, we failed to detect any full-length transcripts. Rather, sense-strand transcripts mapped to the functional domains- ORF1, RT and EN. Secondly, there was strong antisense transcription specifically from RT domain. No antisense transcripts were seen from ORF1. Antisense RT transcripts did not encode known functional peptides. They could possibly be involved in attenuating translation of RT domain, as we failed to detect ORF2p, whereas ORF1p was detectable. Lack of full-length transcripts and strong antisense RT expression may serve to limit EhLINE1 retrotransposition.
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Affiliation(s)
- Devinder Kaur
- School of Environmental Sciences, Jawaharlal Nehru University, India
| | - Mridula Agrahari
- School of Environmental Sciences, Jawaharlal Nehru University, India
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41
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Many Different LINE-1 Retroelements Are Activated in Bladder Cancer. Int J Mol Sci 2020; 21:ijms21249433. [PMID: 33322422 PMCID: PMC7763009 DOI: 10.3390/ijms21249433] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 11/17/2022] Open
Abstract
Human genomes contain about 100,000 LINE-1 (L1) retroelements, of which more than 100 are intact. L1s are normally tightly controlled by epigenetic mechanisms, which often fail in cancer. In bladder urothelial carcinoma (UC), particularly, L1s become DNA-hypomethylated, expressed and contribute to genomic instability and tumor growth. It is, however, unknown which individual L1s are activated. Following RNA-immunoprecipitation with a L1-specific antibody, third generation nanopore sequencing detected transcripts of 90 individual elements in the VM-Cub-1 UC line with high overall L1 expression. In total, 10 L1s accounted for >60% of the reads. Analysis of five specific L1s by RT-qPCR revealed generally increased expression in UC tissues and cell lines over normal controls, but variable expression among tumor cell lines from bladder, prostate and testicular cancer. Chromatin immunoprecipitation demonstrated active histone marks at L1 sequences with increased expression in VM-Cub-1, but not in a different UC cell line with low L1 expression. We conclude that many L1 elements are epigenetically activated in bladder cancer in a varied pattern. Our findings indicate that expression of individual L1s is highly heterogeneous between and among cancer types.
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42
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Linker SB, Randolph-Moore L, Kottilil K, Qiu F, Jaeger BN, Barron J, Gage FH. Identification of bona fide B2 SINE retrotransposon transcription through single-nucleus RNA-seq of the mouse hippocampus. Genome Res 2020; 30:1643-1654. [PMID: 33122305 PMCID: PMC7605253 DOI: 10.1101/gr.262196.120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 09/29/2020] [Indexed: 12/21/2022]
Abstract
Currently, researchers rely on generalized methods to quantify transposable element (TE) RNA expression, such as RT-qPCR and RNA-seq, that do not distinguish between TEs expressed from their own promoter (bona fide) and TEs that are transcribed from a neighboring gene promoter such as within an intron or exon. This distinction is important owing to the differing functional roles of TEs depending on whether they are independently transcribed. Here we report a simple strategy to examine bona fide TE expression, termed BonaFide-TEseq. This approach can be used with any template-switch based library such as Smart-seq2 or the single-cell 5′ gene expression kit from 10x, extending its utility to single-cell RNA-sequencing. This approach does not require TE-specific enrichment, enabling the simultaneous examination of TEs and protein-coding genes. We show that TEs identified through BonaFide-TEseq are expressed from their own promoter, rather than captured as internal products of genes. We reveal the utility of BonaFide-TEseq in the analysis of single-cell data and show that short-interspersed nuclear elements (SINEs) show cell type–specific expression profiles in the mouse hippocampus. We further show that, in response to a brief exposure of home-cage mice to a novel stimulus, SINEs are activated in dentate granule neurons in a time course that is similar to that of protein-coding immediate early genes. This work provides a simple alternative approach to assess bona fide TE transcription at single-cell resolution and provides a proof-of-concept using this method to identify SINE activation in a context that is relevant for normal learning and memory.
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Affiliation(s)
- Sara B Linker
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Lynne Randolph-Moore
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Kalyani Kottilil
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Fan Qiu
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Baptiste N Jaeger
- Laboratory of Neural Plasticity, Faculty of Medicine and Science, Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Jerika Barron
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, California 94143, USA
| | - Fred H Gage
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
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Lanciano S, Cristofari G. Measuring and interpreting transposable element expression. Nat Rev Genet 2020; 21:721-736. [PMID: 32576954 DOI: 10.1038/s41576-020-0251-y] [Citation(s) in RCA: 166] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2020] [Indexed: 12/21/2022]
Abstract
Transposable elements (TEs) are insertional mutagens that contribute greatly to the plasticity of eukaryotic genomes, influencing the evolution and adaptation of species as well as physiology or disease in individuals. Measuring TE expression helps to understand not only when and where TE mobilization can occur but also how this process alters gene expression, chromatin accessibility or cellular signalling pathways. Although genome-wide gene expression assays such as RNA sequencing include transposon-derived transcripts, most computational analytical tools discard or misinterpret TE-derived reads. Emerging approaches are improving the identification of expressed TE loci and helping to discriminate TE transcripts that permit TE mobilization from chimeric gene-TE transcripts or pervasive transcription. Here we review the main challenges associated with the detection of TE expression, including mappability, insertional and internal sequence polymorphisms, and the diversity of the TE transcriptional landscape, as well as the different experimental and computational strategies to solve them.
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Marques DF, Ota VK, Santoro ML, Talarico F, Costa GO, Spindola LM, Cogo-Moreira H, Carvalho CM, Xavier G, Cavalcante DA, Gadelha A, Noto C, Cordeiro Q, Bressan RA, Moretti PN, Belangero SI. LINE-1 hypomethylation is associated with poor risperidone response in a first episode of psychosis cohort. Epigenomics 2020; 12:1041-1051. [DOI: 10.2217/epi-2019-0350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Aim: We investigated the DNA methylation profile over LINE-1 in antipsychotic-naive, first-episode psychosis-patients (n = 69) before and after 2 months of risperidone treatment and in healthy controls (n = 62). Materials & methods: Patients were evaluated using standardized scales and classified as responders and nonresponders. DNA from blood was bisulfite converted and LINE-1 fragments were amplified and pyrosequencing was performed. Results: Lower LINE-1 methylation was observed in antipsychotic-naive first-episode psychosis patients than in healthy controls. Lower DNA methylation levels before treatment were associated with poor risperidone responses. A positive correlation was observed between LINE-1 methylation levels and positive symptoms response. Conclusion: Our study brings new insight regarding how epigenomic studies and clinical correlation studies can supplement psychosis treatment.
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Affiliation(s)
- Diogo Ferri Marques
- Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Genetics Division, Department of Morphology and Genetics, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Vanessa Kiyomi Ota
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Genetics Division, Department of Morphology and Genetics, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Marcos Leite Santoro
- Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Genetics Division, Department of Morphology and Genetics, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Fernanda Talarico
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Genetics Division, Department of Morphology and Genetics, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Giovany Oliveira Costa
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Genetics Division, Department of Morphology and Genetics, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Leticia Maria Spindola
- Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Hugo Cogo-Moreira
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Carolina Muniz Carvalho
- Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Genetics Division, Department of Morphology and Genetics, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Gabriela Xavier
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Genetics Division, Department of Morphology and Genetics, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Daniel Azevedo Cavalcante
- Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Ary Gadelha
- Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Cristiano Noto
- Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Quirino Cordeiro
- Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Department of Psychiatry, Faculdade de Ciências Médicas da Santa Casa de São Paulo, São Paulo, Brazil
| | - Rodrigo Affonseca Bressan
- Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Patricia Natalia Moretti
- Programa de Pós-graduação em Ciências Médicas, Faculdade de Medicina, Universidade de Brasília, Brasília, Brazil
| | - Sintia Iole Belangero
- Department of Psychiatry, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Laboratory of Integrative Neuroscience (LiNC), Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
- Genetics Division, Department of Morphology and Genetics, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
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Burns KH. Our Conflict with Transposable Elements and Its Implications for Human Disease. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2020; 15:51-70. [PMID: 31977294 DOI: 10.1146/annurev-pathmechdis-012419-032633] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Our genome is a historic record of successive invasions of mobile genetic elements. Like other eukaryotes, we have evolved mechanisms to limit their propagation and minimize the functional impact of new insertions. Although these mechanisms are vitally important, they are imperfect, and a handful of retroelement families remain active in modern humans. This review introduces the intrinsic functions of transposons, the tactics employed in their restraint, and the relevance of this conflict to human pathology. The most straightforward examples of disease-causing transposable elements are germline insertions that disrupt a gene and result in a monogenic disease allele. More enigmatic are the abnormal patterns of transposable element expression in disease states. Changes in transposon regulation and cellular responses to their expression have implicated these sequences in diseases as diverse as cancer, autoimmunity, and neurodegeneration. Distinguishing their epiphenomenal from their pathogenic effects may provide wholly new perspectives on our understanding of disease.
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Affiliation(s)
- Kathleen H Burns
- Department of Pathology, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA;
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Marasca F, Gasparotto E, Polimeni B, Vadalà R, Ranzani V, Bodega B. The Sophisticated Transcriptional Response Governed by Transposable Elements in Human Health and Disease. Int J Mol Sci 2020; 21:ijms21093201. [PMID: 32366056 PMCID: PMC7247572 DOI: 10.3390/ijms21093201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 04/29/2020] [Accepted: 04/29/2020] [Indexed: 01/15/2023] Open
Abstract
Transposable elements (TEs), which cover ~45% of the human genome, although firstly considered as “selfish” DNA, are nowadays recognized as driving forces in eukaryotic genome evolution. This capability resides in generating a plethora of sophisticated RNA regulatory networks that influence the cell type specific transcriptome in health and disease. Indeed, TEs are transcribed and their RNAs mediate multi-layered transcriptional regulatory functions in cellular identity establishment, but also in the regulation of cellular plasticity and adaptability to environmental cues, as occurs in the immune response. Moreover, TEs transcriptional deregulation also evolved to promote pathogenesis, as in autoimmune and inflammatory diseases and cancers. Importantly, many of these findings have been achieved through the employment of Next Generation Sequencing (NGS) technologies and bioinformatic tools that are in continuous improvement to overcome the limitations of analyzing TEs sequences. However, they are highly homologous, and their annotation is still ambiguous. Here, we will review some of the most recent findings, questions and improvements to study at high resolution this intriguing portion of the human genome in health and diseases, opening the scenario to novel therapeutic opportunities.
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Affiliation(s)
- Federica Marasca
- Fondazione INGM, Istituto Nazionale di Genetica Molecolare “Enrica e Romeo Invernizzi”, 20122 Milan, Italy; (F.M.); (E.G.); (B.P.); (R.V.); (V.R.)
| | - Erica Gasparotto
- Fondazione INGM, Istituto Nazionale di Genetica Molecolare “Enrica e Romeo Invernizzi”, 20122 Milan, Italy; (F.M.); (E.G.); (B.P.); (R.V.); (V.R.)
| | - Benedetto Polimeni
- Fondazione INGM, Istituto Nazionale di Genetica Molecolare “Enrica e Romeo Invernizzi”, 20122 Milan, Italy; (F.M.); (E.G.); (B.P.); (R.V.); (V.R.)
| | - Rebecca Vadalà
- Fondazione INGM, Istituto Nazionale di Genetica Molecolare “Enrica e Romeo Invernizzi”, 20122 Milan, Italy; (F.M.); (E.G.); (B.P.); (R.V.); (V.R.)
- Translational and Molecular Medicine, DIMET, University of Milan-Bicocca, 20900 Monza, Italy
| | - Valeria Ranzani
- Fondazione INGM, Istituto Nazionale di Genetica Molecolare “Enrica e Romeo Invernizzi”, 20122 Milan, Italy; (F.M.); (E.G.); (B.P.); (R.V.); (V.R.)
| | - Beatrice Bodega
- Fondazione INGM, Istituto Nazionale di Genetica Molecolare “Enrica e Romeo Invernizzi”, 20122 Milan, Italy; (F.M.); (E.G.); (B.P.); (R.V.); (V.R.)
- Correspondence:
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Del Re B, Giorgi G. Long INterspersed element-1 mobility as a sensor of environmental stresses. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2020; 61:465-493. [PMID: 32144842 DOI: 10.1002/em.22366] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 03/03/2020] [Accepted: 03/04/2020] [Indexed: 06/10/2023]
Abstract
Long INterspersed element (LINE-1, L1) retrotransposons are the most abundant transposable elements in the human genome, constituting approximately 17%. They move by a "copy-paste" mechanism, involving reverse transcription of an RNA intermediate and insertion of its cDNA copy at a new site in the genome. L1 retrotransposition (L1-RTP) can cause insertional mutations, alter gene expression, transduce exons, and induce epigenetic dysregulation. L1-RTP is generally repressed; however, a number of observations collected over about 15 years revealed that it can occur in response to environmental stresses. Moreover, emerging evidence indicates that L1-RTP can play a role in the onset of several neurological and oncological diseases in humans. In recent years, great attention has been paid to the exposome paradigm, which proposes that health effects of an environmental factor should be evaluated considering both cumulative environmental exposures and the endogenous processes resulting from the biological response. L1-RTP could be an endogenous process considered for this application. Here, we summarize the current understanding of environmental factors that can affect the retrotransposition of human L1 elements. Evidence indicates that L1-RTP alteration is triggered by numerous and various environmental stressors, such as chemical agents (heavy metals, carcinogens, oxidants, and drugs), physical agents (ionizing and non-ionizing radiations), and experiential factors (voluntary exercise, social isolation, maternal care, and environmental light/dark cycles). These data come from in vitro studies on cell lines and in vivo studies on transgenic animals: future investigations should be focused on physiologically relevant models to gain a better understanding of this topic.
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Affiliation(s)
- Brunella Del Re
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Gianfranco Giorgi
- Department of Biological, Geological and Environmental Sciences, Alma Mater Studiorum University of Bologna, Bologna, Italy
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48
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Lou C, Goodier JL, Qiang R. A potential new mechanism for pregnancy loss: considering the role of LINE-1 retrotransposons in early spontaneous miscarriage. Reprod Biol Endocrinol 2020; 18:6. [PMID: 31964400 PMCID: PMC6971995 DOI: 10.1186/s12958-020-0564-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 01/07/2020] [Indexed: 12/14/2022] Open
Abstract
LINE1 retrotransposons are mobile DNA elements that copy and paste themselves into new sites in the genome. To ensure their evolutionary success, heritable new LINE-1 insertions accumulate in cells that can transmit genetic information to the next generation (i.e., germ cells and embryonic stem cells). It is our hypothesis that LINE1 retrotransposons, insertional mutagens that affect expression of genes, may be causal agents of early miscarriage in humans. The cell has evolved various defenses restricting retrotransposition-caused mutation, but these are occasionally relaxed in certain somatic cell types, including those of the early embryo. We predict that reduced suppression of L1s in germ cells or early-stage embryos may lead to excessive genome mutation by retrotransposon insertion, or to the induction of an inflammatory response or apoptosis due to increased expression of L1-derived nucleic acids and proteins, and so disrupt gene function important for embryogenesis. If correct, a novel threat to normal human development is revealed, and reverse transcriptase therapy could be one future strategy for controlling this cause of embryonic damage in patients with recurrent miscarriages.
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Affiliation(s)
- Chao Lou
- Department of Genetics, Northwest Women’s and Children’s Hospital, 1616 Yanxiang Road, Xi’an, Shaanxi Province People’s Republic of China
| | - John L. Goodier
- 0000 0001 2171 9311grid.21107.35McKusick-Nathans Deartment of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Rong Qiang
- Department of Genetics, Northwest Women’s and Children’s Hospital, 1616 Yanxiang Road, Xi’an, Shaanxi Province People’s Republic of China
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Kaul T, Morales ME, Sartor AO, Belancio VP, Deininger P. Comparative analysis on the expression of L1 loci using various RNA-Seq preparations. Mob DNA 2020; 11:2. [PMID: 31921361 PMCID: PMC6945437 DOI: 10.1186/s13100-019-0194-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 12/05/2019] [Indexed: 01/08/2023] Open
Abstract
Background Retrotransposons are one of the oldest evolutionary forces shaping mammalian genomes, with the ability to mobilize from one genomic location to another. This mobilization is also a significant factor in human disease. The only autonomous human retroelement, L1, has propagated to make up 17% of the human genome, accumulating over 500,000 copies. The majority of these loci are truncated or defective with only a few reported to remain capable of retrotransposition. We have previously published a strand-specific RNA-Seq bioinformatics approach to stringently identify at the locus-specific level the few expressed full-length L1s using cytoplasmic RNA. With growing repositories of RNA-Seq data, there is potential to mine these datasets to identify and study expressed L1s at single-locus resolution, although many datasets are not strand-specific or not generated from cytoplasmic RNA. Results We developed whole-cell, cytoplasmic and nuclear RNA-Seq datasets from 22Rv1 prostate cancer cells to test the influence of different preparations on the quality and effort needed to measure L1 expression. We found that there was minimal data loss in the identification of full-length expressed L1 s using whole cell, strand-specific RNA-Seq data compared to cytoplasmic, strand-specific RNA-Seq data. However, this was only possible with an increased amount of manual curation of the bioinformatics output to eliminate increased background. About half of the data was lost when the sequenced datasets were non-strand specific. Conclusions The results of these studies demonstrate that with rigorous manual curation the utilization of stranded RNA-Seq datasets allow identification of expressed L1 loci from either cytoplasmic or whole-cell RNA-Seq datasets.
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Affiliation(s)
- Tiffany Kaul
- 1Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112 USA
| | - Maria E Morales
- 1Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112 USA
| | - Alton O Sartor
- 1Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112 USA.,2Section of Hematology and Oncology, Department of Medicine, Tulane School of Medicine, 1430 Tulane Ave, New Orleans, LA 70112 USA
| | - Victoria P Belancio
- 1Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112 USA.,3Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans, 70112 USA
| | - Prescott Deininger
- 1Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112 USA.,4Department of Epidemiology, Tulane School of Public Health and Tropical Medicine, New Orleans, LA 70112 USA
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50
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Ardeljan D, Wang X, Oghbaie M, Taylor MS, Husband D, Deshpande V, Steranka JP, Gorbounov M, Yang WR, Sie B, Larman HB, Jiang H, Molloy KR, Altukhov I, Li Z, McKerrow W, Fenyö D, Burns KH, LaCava J. LINE-1 ORF2p expression is nearly imperceptible in human cancers. Mob DNA 2019; 11:1. [PMID: 31892958 PMCID: PMC6937734 DOI: 10.1186/s13100-019-0191-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 11/22/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Long interspersed element-1 (LINE-1, L1) is the major driver of mobile DNA activity in modern humans. When expressed, LINE-1 loci produce bicistronic transcripts encoding two proteins essential for retrotransposition, ORF1p and ORF2p. Many types of human cancers are characterized by L1 promoter hypomethylation, L1 transcription, L1 ORF1p protein expression, and somatic L1 retrotransposition. ORF2p encodes the endonuclease and reverse transcriptase activities required for L1 retrotransposition. Its expression is poorly characterized in human tissues and cell lines. RESULTS We report mass spectrometry-based tumor proteome profiling studies wherein ORF2p eludes detection. To test whether ORF2p could be detected with specific reagents, we developed and validated five rabbit monoclonal antibodies with immunoreactivity for specific epitopes on the protein. These reagents readily detect ectopic ORF2p expressed from bicistronic L1 constructs. However, endogenous ORF2p is not detected in human tumor samples or cell lines by western blot, immunoprecipitation, or immunohistochemistry despite high levels of ORF1p expression. Moreover, we report endogenous ORF1p-associated interactomes, affinity isolated from colorectal cancers, wherein we similarly fail to detect ORF2p. These samples include primary tumors harboring hundreds of somatically acquired L1 insertions. The new data are available via ProteomeXchange with identifier PXD013743. CONCLUSIONS Although somatic retrotransposition provides unequivocal genetic evidence for the expression of ORF2p in human cancers, we are unable to directly measure its presence using several standard methods. Experimental systems have previously indicated an unequal stoichiometry between ORF1p and ORF2p, but in vivo, the expression of these two proteins may be more strikingly uncoupled. These findings are consistent with observations that ORF2p is not tolerable for cell growth.
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Affiliation(s)
- Daniel Ardeljan
- McKusick Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Xuya Wang
- Institute for Systems Genetics, Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016 USA
| | - Mehrnoosh Oghbaie
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065 USA
| | - Martin S. Taylor
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 USA
| | - David Husband
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Vikram Deshpande
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 USA
| | - Jared P. Steranka
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Mikhail Gorbounov
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Wan Rou Yang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Brandon Sie
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - H. Benjamin Larman
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Hua Jiang
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065 USA
| | - Kelly R. Molloy
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY 10065 USA
| | - Ilya Altukhov
- Moscow Institute of Physics and Technology, Dolgoprudny, 141701 Russia
| | - Zhi Li
- Institute for Systems Genetics, Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016 USA
| | - Wilson McKerrow
- Institute for Systems Genetics, Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016 USA
| | - David Fenyö
- Institute for Systems Genetics, Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016 USA
| | - Kathleen H. Burns
- McKusick Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - John LaCava
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065 USA
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, Groningen, 9713 AV The Netherlands
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