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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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2
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Cheng KCL, Frost JM, Sánchez-Luque FJ, García-Canãdas M, Taylor D, Yang WR, Irayanar B, Sampath S, Patani H, Agger K, Helin K, Ficz G, Burns KH, Ewing A, García-Pérez JL, Branco MR. Vitamin C activates young LINE-1 elements in mouse embryonic stem cells via H3K9me3 demethylation. Epigenetics Chromatin 2023; 16:39. [PMID: 37845773 PMCID: PMC10578016 DOI: 10.1186/s13072-023-00514-6] [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: 08/07/2023] [Accepted: 10/06/2023] [Indexed: 10/18/2023] Open
Abstract
BACKGROUND Vitamin C (vitC) enhances the activity of 2-oxoglutarate-dependent dioxygenases, including TET enzymes, which catalyse DNA demethylation, and Jumonji-domain histone demethylases. The epigenetic remodelling promoted by vitC improves the efficiency of induced pluripotent stem cell derivation, and is required to attain a ground-state of pluripotency in embryonic stem cells (ESCs) that closely mimics the inner cell mass of the early blastocyst. However, genome-wide DNA and histone demethylation can lead to upregulation of transposable elements (TEs), and it is not known how vitC addition in culture media affects TE expression in pluripotent stem cells. RESULTS Here we show that vitC increases the expression of several TE families, including evolutionarily young LINE-1 (L1) elements, in mouse ESCs. We find that TET activity is dispensable for L1 upregulation, and that instead it occurs largely as a result of H3K9me3 loss mediated by KDM4A/C histone demethylases. Despite increased L1 levels, we did not detect increased somatic insertion rates in vitC-treated cells. Notably, treatment of human ESCs with vitC also increases L1 protein levels, albeit through a distinct, post-transcriptional mechanism. CONCLUSION VitC directly modulates the expression of mouse L1s and other TEs through epigenetic mechanisms, with potential for downstream effects related to the multiple emerging roles of L1s in cellular function.
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Affiliation(s)
- Kevin C L Cheng
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, E1 2AT, UK
- Computational Biology Program, Ontario Institute for Cancer Research, Toronto, ON, Canada
| | - Jennifer M Frost
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, E1 2AT, UK
| | - Francisco J Sánchez-Luque
- Institute of Parasitology and Biomedicine "Lopez-Neyra" (IPBLN), Spanish National Research Council (CSIC), PTS Granada, Granada, Spain
| | - Marta García-Canãdas
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain
| | - Darren Taylor
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, E1 2AT, UK
- MRC London Institute of Medical Sciences, London, W12 0NN, UK
| | - Wan R Yang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Branavy Irayanar
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, E1 2AT, UK
| | - Swetha Sampath
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, E1 2AT, UK
| | - Hemalvi Patani
- Barts Cancer Institute, Faculty of Medicine and Dentistry, QMUL, London, EC1M 6BQ, UK
| | - Karl Agger
- The Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, Copenhagen, Denmark
| | - Kristian Helin
- The Novo Nordisk Foundation Center for Stem Cell Biology (DanStem), University of Copenhagen, Copenhagen, Denmark
- The Institute of Cancer Research, London, UK
| | - Gabriella Ficz
- Barts Cancer Institute, Faculty of Medicine and Dentistry, QMUL, London, EC1M 6BQ, UK
| | - Kathleen H Burns
- Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - Adam Ewing
- Mater Research Institute, University of Queensland, Woolloongabba, QLD, 4102, Australia
| | - José L García-Pérez
- Pfizer-University of Granada-Andalusian Government Centre for Genomics and Oncological Research (GENYO), PTS Granada, Granada, Spain
| | - Miguel R Branco
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, E1 2AT, UK.
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Zhao P, Peng C, Fang L, Wang Z, Liu GE. Taming transposable elements in livestock and poultry: a review of their roles and applications. Genet Sel Evol 2023; 55:50. [PMID: 37479995 PMCID: PMC10362595 DOI: 10.1186/s12711-023-00821-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 06/30/2023] [Indexed: 07/23/2023] Open
Abstract
Livestock and poultry play a significant role in human nutrition by converting agricultural by-products into high-quality proteins. To meet the growing demand for safe animal protein, genetic improvement of livestock must be done sustainably while minimizing negative environmental impacts. Transposable elements (TE) are important components of livestock and poultry genomes, contributing to their genetic diversity, chromatin states, gene regulatory networks, and complex traits of economic value. However, compared to other species, research on TE in livestock and poultry is still in its early stages. In this review, we analyze 72 studies published in the past 20 years, summarize the TE composition in livestock and poultry genomes, and focus on their potential roles in functional genomics. We also discuss bioinformatic tools and strategies for integrating multi-omics data with TE, and explore future directions, feasibility, and challenges of TE research in livestock and poultry. In addition, we suggest strategies to apply TE in basic biological research and animal breeding. Our goal is to provide a new perspective on the importance of TE in livestock and poultry genomes.
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Affiliation(s)
- Pengju Zhao
- Hainan Institute of Zhejiang University, Hainan Sanya, 572000, China
- College of Animal Sciences, Zhejiang University, Zhejiang, Hangzhou, People's Republic of China
| | - Chen Peng
- Hainan Institute of Zhejiang University, Hainan Sanya, 572000, China
- College of Animal Sciences, Zhejiang University, Zhejiang, Hangzhou, People's Republic of China
| | - Lingzhao Fang
- Center for Quantitative Genetics and Genomics, Aarhus University, 8000, Aarhus, Denmark.
| | - Zhengguang Wang
- Hainan Institute of Zhejiang University, Hainan Sanya, 572000, China.
- College of Animal Sciences, Zhejiang University, Zhejiang, Hangzhou, People's Republic of China.
| | - George E Liu
- Animal Genomics and Improvement Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, MD, 20705, USA.
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Banouh M, Armisen D, Bouguennec A, Huneau C, Sow MD, Pont C, Salse J, Civáň P. Low impact of polyploidization on the transcriptome of synthetic allohexaploid wheat. BMC Genomics 2023; 24:255. [PMID: 37170217 PMCID: PMC10173476 DOI: 10.1186/s12864-023-09324-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/20/2023] [Indexed: 05/13/2023] Open
Abstract
BACKGROUND Bread wheat is a recent allohexaploid (genomic constitution AABBDD) that emerged through a hybridization between tetraploid Triticum turgidum (AABB) and diploid Aegilops tauschii (DD) less than 10,000 years ago. The hexaploidization can be re-created artificially, producing synthetic wheat that has been used to study immediate genomic responses to polyploidization. The scale of the consequences of polyploidization, and their mechanism of establishment, remain uncertain. RESULTS Here we sampled several synthetic wheats from alternative parental genotypes and reciprocal crosses, and examined transcriptomes from two different tissues and successive generations. We did not detect any massive reprogramming in gene expression, with only around 1% of expressed genes showing significant differences compared to their lower-ploidy parents. Most of this differential expression is located on the D subgenome, without consistency in the direction of the expression change. Homoeolog expression bias in synthetic wheat is similar to the pattern observed in the parents. Both differential expression and homoeolog bias are tissue-specific. While up to three families of transposable elements became upregulated in wheat synthetics, their position and distance are not significantly associated with expression changes in proximal genes. DISCUSSION While only a few genes change their expression pattern after polyploidization, they can be involved in agronomically important pathways. Alternative parental combinations can lead to opposite changes on the same subset of D-located genes, which is relevant for harnessing new diversity in wheat breeding. Tissue specificity of the polyploidization-triggered expression changes indicates the remodelling of transcriptomes in synthetic wheat is plastic and likely caused by regulome interactions rather than permanent changes. We discuss the pitfalls of transcriptomic comparisons across ploidy levels that can inflate the de-regulation signal. CONCLUSIONS Transcriptomic response to polyploidization in synthetic AABBDD wheat is modest and much lower than some previous estimates. Homoeolog expression bias in wheat allohexaploids is mostly attributed to parental legacy, with polyploidy having a mild balancing effect.
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Grants
- PolyBléD Fonds de Soutien à l'Obtention Végétale
- SeedEX, SeedENCODE, MethylWheat Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
- SeedEX, SeedENCODE, MethylWheat Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
- SeedEX, SeedENCODE, MethylWheat Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
- SeedEX, SeedENCODE, MethylWheat Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
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Affiliation(s)
- Meriem Banouh
- INRAE/UCA UMR 1095, 5 Chemin de Beaulieu, Clermont Ferrand, 63100, France
| | - David Armisen
- Institut de Génomique Fonctionnelle de Lyon, CNRS UMR 5242, 46 allée d'Italie, Lyon, 69364, France
| | - Annaig Bouguennec
- INRAE/UCA UMR 1095, 5 Chemin de Beaulieu, Clermont Ferrand, 63100, France
| | - Cécile Huneau
- INRAE/UCA UMR 1095, 5 Chemin de Beaulieu, Clermont Ferrand, 63100, France
| | - Mamadou Dia Sow
- INRAE/UCA UMR 1095, 5 Chemin de Beaulieu, Clermont Ferrand, 63100, France
| | - Caroline Pont
- INRAE/UCA UMR 1095, 5 Chemin de Beaulieu, Clermont Ferrand, 63100, France
| | - Jérôme Salse
- INRAE/UCA UMR 1095, 5 Chemin de Beaulieu, Clermont Ferrand, 63100, France
| | - Peter Civáň
- INRAE/UCA UMR 1095, 5 Chemin de Beaulieu, Clermont Ferrand, 63100, France.
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5
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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: 4] [Impact Index Per Article: 4.0] [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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6
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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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7
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 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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8
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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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Meta-Analysis Suggests That Intron Retention Can Affect Quantification of Transposable Elements from RNA-Seq Data. BIOLOGY 2022; 11:biology11060826. [PMID: 35741347 PMCID: PMC9220773 DOI: 10.3390/biology11060826] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/20/2022] [Accepted: 05/26/2022] [Indexed: 02/08/2023]
Abstract
Simple Summary Transposable elements (TEs) are repetitive sequences comprising more than one third of the human genome with the original ability to change their location within the genome. Owing to their repetitive nature, the quantification of TEs results often challenging. RNA-seq is a useful tool for genome-wide TEs quantification, nevertheless it also presents technical issues, including low reads mappability and erroneous quantification derived from the transcription of TEs fragments embedded in canonical transcripts. Fragments derived from TEs are found within the introns of most genes, which led to the hypothesis that intron retention (IR) can affect the unbiased quantification of TEs expression. Performing meta-analysis of public RNA-seq datasets, here we observe that IR can indeed impact the quantification of TEs by increasing the number of reads mapped on intronic TE copies. Our work highlights a correlation between IR and TEs expression measurement by RNA-seq that should be taken into account to achieve reliable TEs quantification, especially in samples characterized by extensive IR, because differential IR might be confused with differential TEs expression. Abstract Transposable elements (TEs), also known as “jumping genes”, are repetitive sequences with the capability of changing their location within the genome. They are key players in many different biological processes in health and disease. Therefore, a reliable quantification of their expression as transcriptional units is crucial to distinguish between their independent expression and the transcription of their sequences as part of canonical transcripts. TEs quantification faces difficulties of different types, the most important one being low reads mappability due to their repetitive nature preventing an unambiguous mapping of reads originating from their sequences. A large fraction of TEs fragments localizes within introns, which led to the hypothesis that intron retention (IR) can be an additional source of bias, potentially affecting accurate TEs quantification. IR occurs when introns, normally removed from the mature transcript by the splicing machinery, are maintained in mature transcripts. IR is a widespread mechanism affecting many different genes with cell type-specific patterns. We hypothesized that, in an RNA-seq experiment, reads derived from retained introns can introduce a bias in the detection of overlapping, independent TEs RNA expression. In this study we performed meta-analysis using public RNA-seq data from lymphoblastoid cell lines and show that IR can impact TEs quantification using established tools with default parameters. Reads mapped on intronic TEs were indeed associated to the expression of TEs and influence their correct quantification as independent transcriptional units. We confirmed these results using additional independent datasets, demonstrating that this bias does not appear in samples where IR is not present and that differential TEs expression does not impact on IR quantification. We concluded that IR causes the over-quantification of intronic TEs and differential IR might be confused with differential TEs expression. Our results should be taken into account for a correct quantification of TEs expression from RNA-seq data, especially in samples in which IR is abundant.
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10
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McKerrow W, Wang X, Mendez-Dorantes C, Mita P, Cao S, Grivainis M, Ding L, LaCava J, Burns KH, Boeke JD, Fenyö D. LINE-1 expression in cancer correlates with p53 mutation, copy number alteration, and S phase checkpoint. Proc Natl Acad Sci U S A 2022; 119:e2115999119. [PMID: 35169076 PMCID: PMC8872788 DOI: 10.1073/pnas.2115999119] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 01/14/2022] [Indexed: 12/12/2022] Open
Abstract
Retrotransposons are genomic DNA sequences that copy themselves to new genomic locations via RNA intermediates; LINE-1 is the only active and autonomous retrotransposon in the human genome. The mobility of LINE-1 is largely repressed in somatic tissues but is derepressed in many cancers, where LINE-1 retrotransposition is correlated with p53 mutation and copy number alteration (CNA). In cell lines, inducing LINE-1 expression can cause double-strand breaks (DSBs) and replication stress. Reanalyzing multiomic data from breast, ovarian, endometrial, and colon cancers, we confirmed correlations between LINE-1 expression, p53 mutation status, and CNA. We observed a consistent correlation between LINE-1 expression and the abundance of DNA replication complex components, indicating that LINE-1 may also induce replication stress in human tumors. In endometrial cancer, high-quality phosphoproteomic data allowed us to identify the DSB-induced ATM-MRN-SMC S phase checkpoint pathway as the primary DNA damage response (DDR) pathway associated with LINE-1 expression. Induction of LINE-1 expression in an in vitro model led to increased phosphorylation of MRN complex member RAD50, suggesting that LINE-1 directly activates this pathway.
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Affiliation(s)
- Wilson McKerrow
- Institute for Systems Genetics, New York University Grossman School of Medicine, New York, NY 10016
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016
| | - Xuya Wang
- Institute for Systems Genetics, New York University Grossman School of Medicine, New York, NY 10016
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016
| | - Carlos Mendez-Dorantes
- Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA 02215
- Department of Pathology, Harvard Medical School, Boston, MA 02115
| | - Paolo Mita
- Institute for Systems Genetics, New York University Grossman School of Medicine, New York, NY 10016
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016
| | - Song Cao
- Department of Medicine and Genetics, Siteman Cancer Center, Washington University in St. Louis, St. Louis, MO 63110
- McDonnell Genome Institute, Washington University in St. Louis, St. Louis, MO 63108
| | - Mark Grivainis
- Institute for Systems Genetics, New York University Grossman School of Medicine, New York, NY 10016
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016
| | - Li Ding
- Department of Medicine and Genetics, Siteman Cancer Center, Washington University in St. Louis, St. Louis, MO 63110
- McDonnell Genome Institute, Washington University in St. Louis, St. Louis, MO 63108
| | - John LaCava
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands
| | - Kathleen H Burns
- Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA 02215
- Department of Pathology, Harvard Medical School, Boston, MA 02115
| | - Jef D Boeke
- Institute for Systems Genetics, New York University Grossman School of Medicine, New York, NY 10016;
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016
- Department of Biomedical Engineering, Tandon School of Engineering, Brooklyn, NY11201
| | - David Fenyö
- Institute for Systems Genetics, New York University Grossman School of Medicine, New York, NY 10016;
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016
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11
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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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12
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Gupta R, Srivastava D, Sahu M, Tiwari S, Ambasta RK, Kumar P. Artificial intelligence to deep learning: machine intelligence approach for drug discovery. Mol Divers 2021; 25:1315-1360. [PMID: 33844136 PMCID: PMC8040371 DOI: 10.1007/s11030-021-10217-3] [Citation(s) in RCA: 253] [Impact Index Per Article: 84.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/22/2021] [Indexed: 02/06/2023]
Abstract
Drug designing and development is an important area of research for pharmaceutical companies and chemical scientists. However, low efficacy, off-target delivery, time consumption, and high cost impose a hurdle and challenges that impact drug design and discovery. Further, complex and big data from genomics, proteomics, microarray data, and clinical trials also impose an obstacle in the drug discovery pipeline. Artificial intelligence and machine learning technology play a crucial role in drug discovery and development. In other words, artificial neural networks and deep learning algorithms have modernized the area. Machine learning and deep learning algorithms have been implemented in several drug discovery processes such as peptide synthesis, structure-based virtual screening, ligand-based virtual screening, toxicity prediction, drug monitoring and release, pharmacophore modeling, quantitative structure-activity relationship, drug repositioning, polypharmacology, and physiochemical activity. Evidence from the past strengthens the implementation of artificial intelligence and deep learning in this field. Moreover, novel data mining, curation, and management techniques provided critical support to recently developed modeling algorithms. In summary, artificial intelligence and deep learning advancements provide an excellent opportunity for rational drug design and discovery process, which will eventually impact mankind. The primary concern associated with drug design and development is time consumption and production cost. Further, inefficiency, inaccurate target delivery, and inappropriate dosage are other hurdles that inhibit the process of drug delivery and development. With advancements in technology, computer-aided drug design integrating artificial intelligence algorithms can eliminate the challenges and hurdles of traditional drug design and development. Artificial intelligence is referred to as superset comprising machine learning, whereas machine learning comprises supervised learning, unsupervised learning, and reinforcement learning. Further, deep learning, a subset of machine learning, has been extensively implemented in drug design and development. The artificial neural network, deep neural network, support vector machines, classification and regression, generative adversarial networks, symbolic learning, and meta-learning are examples of the algorithms applied to the drug design and discovery process. Artificial intelligence has been applied to different areas of drug design and development process, such as from peptide synthesis to molecule design, virtual screening to molecular docking, quantitative structure-activity relationship to drug repositioning, protein misfolding to protein-protein interactions, and molecular pathway identification to polypharmacology. Artificial intelligence principles have been applied to the classification of active and inactive, monitoring drug release, pre-clinical and clinical development, primary and secondary drug screening, biomarker development, pharmaceutical manufacturing, bioactivity identification and physiochemical properties, prediction of toxicity, and identification of mode of action.
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Affiliation(s)
- Rohan Gupta
- Molecular Neuroscience and Functional Genomics Laboratory, Department of Biotechnology, Delhi Technological University (Formerly DCE), Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Devesh Srivastava
- Molecular Neuroscience and Functional Genomics Laboratory, Department of Biotechnology, Delhi Technological University (Formerly DCE), Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Mehar Sahu
- Molecular Neuroscience and Functional Genomics Laboratory, Department of Biotechnology, Delhi Technological University (Formerly DCE), Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Swati Tiwari
- Molecular Neuroscience and Functional Genomics Laboratory, Department of Biotechnology, Delhi Technological University (Formerly DCE), Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Rashmi K Ambasta
- Molecular Neuroscience and Functional Genomics Laboratory, Department of Biotechnology, Delhi Technological University (Formerly DCE), Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Pravir Kumar
- Molecular Neuroscience and Functional Genomics Laboratory, Department of Biotechnology, Delhi Technological University (Formerly DCE), Shahbad Daulatpur, Bawana Road, Delhi, 110042, India.
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13
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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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14
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Koenig MJ, Agana BA, Kaufman JM, Sharpnack MF, Wang WZ, Weigel C, Navarro FCP, Amann JM, Cacciato N, Arasada RR, Gerstein MB, Wysocki VH, Oakes C, Carbone DP. STK11/LKB1 Loss of Function Is Associated with Global DNA Hypomethylation and S-Adenosyl-Methionine Depletion in Human Lung Adenocarcinoma. Cancer Res 2021; 81:4194-4204. [PMID: 34045189 DOI: 10.1158/0008-5472.can-20-3199] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 04/14/2021] [Accepted: 05/24/2021] [Indexed: 11/16/2022]
Abstract
STK11 (liver kinase B1, LKB1) is the fourth most frequently mutated gene in lung adenocarcinoma, with loss of function observed in up to 30% of all cases. Our previous work identified a 16-gene signature for LKB1 loss of function through mutational and nonmutational mechanisms. In this study, we applied this genetic signature to The Cancer Genome Atlas (TCGA) lung adenocarcinoma samples and discovered a novel association between LKB1 loss and widespread DNA demethylation. LKB1-deficient tumors showed depletion of S-adenosyl-methionine (SAM-e), which is the primary substrate for DNMT1 activity. Lower methylation following LKB1 loss involved repetitive elements (RE) and altered RE transcription, as well as decreased sensitivity to azacytidine. Demethylated CpGs were enriched for FOXA family consensus binding sites, and nuclear expression, localization, and turnover of FOXA was dependent upon LKB1. Overall, these findings demonstrate that a large number of lung adenocarcinomas exhibit global hypomethylation driven by LKB1 loss, which has implications for both epigenetic therapy and immunotherapy in these cancers. SIGNIFICANCE: Lung adenocarcinomas with LKB1 loss demonstrate global genomic hypomethylation associated with depletion of SAM-e, reduced expression of DNMT1, and increased transcription of repetitive elements.
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Affiliation(s)
- Michael J Koenig
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio.
| | - Bernice A Agana
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio
| | - Jacob M Kaufman
- Department of Medicine, Duke University, Durham, North Carolina
| | | | - Walter Z Wang
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio
| | - Christoph Weigel
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio
| | - Fabio C P Navarro
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut
| | - Joseph M Amann
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio
| | - Nicole Cacciato
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio
| | | | - Mark B Gerstein
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut.,Department of Computer Science, Yale University, New Haven, Connecticut
| | - Vicki H Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio
| | - Christopher Oakes
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio
| | - David P Carbone
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio.
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15
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Shao W, Wang T. Transcript assembly improves expression quantification of transposable elements in single-cell RNA-seq data. Genome Res 2021; 31:88-100. [PMID: 33355230 PMCID: PMC7849386 DOI: 10.1101/gr.265173.120] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 11/24/2020] [Indexed: 12/28/2022]
Abstract
Transposable elements (TEs) are an integral part of the host transcriptome. TE-containing noncoding RNAs (ncRNAs) show considerable tissue specificity and play important roles during development, including stem cell maintenance and cell differentiation. Recent advances in single-cell RNA-seq (scRNA-seq) revolutionized cell type-specific gene expression analysis. However, effective scRNA-seq quantification tools tailored for TEs are lacking, limiting our ability to dissect TE expression dynamics at single-cell resolution. To address this issue, we established a TE expression quantification pipeline that is compatible with scRNA-seq data generated across multiple technology platforms. We constructed TE-containing ncRNA references using bulk RNA-seq data and showed that quantifying TE expression at the transcript level effectively reduces noise. As proof of principle, we applied this strategy to mouse embryonic stem cells and successfully captured the expression profile of endogenous retroviruses in single cells. We further expanded our analysis to scRNA-seq data from early stages of mouse embryogenesis. Our results illustrated the dynamic TE expression at preimplantation stages and revealed 146 TE-containing ncRNA transcripts with substantial tissue specificity during gastrulation and early organogenesis.
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Affiliation(s)
- Wanqing Shao
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
- Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Ting Wang
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
- Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, Missouri 63108, USA
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16
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Palacios-Gimenez OM, Koelman J, Palmada-Flores M, Bradford TM, Jones KK, Cooper SJB, Kawakami T, Suh A. Comparative analysis of morabine grasshopper genomes reveals highly abundant transposable elements and rapidly proliferating satellite DNA repeats. BMC Biol 2020; 18:199. [PMID: 33349252 PMCID: PMC7754599 DOI: 10.1186/s12915-020-00925-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 11/10/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Repetitive DNA sequences, including transposable elements (TEs) and tandemly repeated satellite DNA (satDNAs), collectively called the "repeatome", are found in high proportion in organisms across the Tree of Life. Grasshoppers have large genomes, averaging 9 Gb, that contain a high proportion of repetitive DNA, which has hampered progress in assembling reference genomes. Here we combined linked-read genomics with transcriptomics to assemble, characterize, and compare the structure of repetitive DNA sequences in four chromosomal races of the morabine grasshopper Vandiemenella viatica species complex and determine their contribution to genome evolution. RESULTS We obtained linked-read genome assemblies of 2.73-3.27 Gb from estimated genome sizes of 4.26-5.07 Gb DNA per haploid genome of the four chromosomal races of V. viatica. These constitute the third largest insect genomes assembled so far. Combining complementary annotation tools and manual curation, we found a large diversity of TEs and satDNAs, constituting 66 to 75% per genome assembly. A comparison of sequence divergence within the TE classes revealed massive accumulation of recent TEs in all four races (314-463 Mb per assembly), indicating that their large genome sizes are likely due to similar rates of TE accumulation. Transcriptome sequencing showed more biased TE expression in reproductive tissues than somatic tissues, implying permissive transcription in gametogenesis. Out of 129 satDNA families, 102 satDNA families were shared among the four chromosomal races, which likely represent a diversity of satDNA families in the ancestor of the V. viatica chromosomal races. Notably, 50 of these shared satDNA families underwent differential proliferation since the recent diversification of the V. viatica species complex. CONCLUSION This in-depth annotation of the repeatome in morabine grasshoppers provided new insights into the genome evolution of Orthoptera. Our TEs analysis revealed a massive recent accumulation of TEs equivalent to the size of entire Drosophila genomes, which likely explains the large genome sizes in grasshoppers. Despite an overall high similarity of the TE and satDNA diversity between races, the patterns of TE expression and satDNA proliferation suggest rapid evolution of grasshopper genomes on recent timescales.
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Affiliation(s)
- Octavio M Palacios-Gimenez
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden.
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden.
| | - Julia Koelman
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden
| | - Marc Palmada-Flores
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden
| | - Tessa M Bradford
- Evolutionary Biology Unit, South Australian Museum, Adelaide, SA, 5000, Australia
- School of Biological Sciences and Australian Centre for Evolutionary Biology and Biodiversity, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Karl K Jones
- Evolutionary Biology Unit, South Australian Museum, Adelaide, SA, 5000, Australia
| | - Steven J B Cooper
- Evolutionary Biology Unit, South Australian Museum, Adelaide, SA, 5000, Australia
- School of Biological Sciences and Australian Centre for Evolutionary Biology and Biodiversity, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Takeshi Kawakami
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden.
- Embark Veterinary, Inc., Boston, MA, USA.
| | - Alexander Suh
- Department of Ecology and Genetics - Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden.
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden.
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TU, UK.
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17
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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: 161] [Impact Index Per Article: 40.3] [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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18
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Bravo JI, Nozownik S, Danthi PS, Benayoun BA. Transposable elements, circular RNAs and mitochondrial transcription in age-related genomic regulation. Development 2020; 147:dev175786. [PMID: 32527937 PMCID: PMC10680986 DOI: 10.1242/dev.175786] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Our understanding of the molecular regulation of aging and age-related diseases is still in its infancy, requiring in-depth characterization of the molecular landscape shaping these complex phenotypes. Emerging classes of molecules with promise as aging modulators include transposable elements, circRNAs and the mitochondrial transcriptome. Analytical complexity means that these molecules are often overlooked, even though they exhibit strong associations with aging and, in some cases, may directly contribute to its progress. Here, we review the links between these novel factors and age-related phenotypes, and we suggest tools that can be easily incorporated into existing pipelines to better understand the aging process.
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Affiliation(s)
- Juan I Bravo
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
- Graduate Program in the Biology of Aging, University of Southern California, Los Angeles, CA 90089, USA
| | - Séverine Nozownik
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
- Magistère européen de Génétique, Université Paris Diderot-Paris 7, Paris 75014, France
| | - Prakroothi S Danthi
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Bérénice A Benayoun
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089, USA
- USC Norris Comprehensive Cancer Center, Epigenetics and Gene Regulation, Los Angeles, CA 90089, USA
- USC Stem Cell Initiative, Los Angeles, CA 90089, USA
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19
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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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20
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O'Neill K, Brocks D, Hammell MG. Mobile genomics: tools and techniques for tackling transposons. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190345. [PMID: 32075565 PMCID: PMC7061981 DOI: 10.1098/rstb.2019.0345] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2019] [Indexed: 12/22/2022] Open
Abstract
Next-generation sequencing approaches have fundamentally changed the types of questions that can be asked about gene function and regulation. With the goal of approaching truly genome-wide quantifications of all the interaction partners and downstream effects of particular genes, these quantitative assays have allowed for an unprecedented level of detail in exploring biological interactions. However, many challenges remain in our ability to accurately describe and quantify the interactions that take place in those hard to reach and extremely repetitive regions of our genome comprised mostly of transposable elements (TEs). Tools dedicated to TE-derived sequences have lagged behind, making the inclusion of these sequences in genome-wide analyses difficult. Recent improvements, both computational and experimental, allow for the better inclusion of TE sequences in genomic assays and a renewed appreciation for the importance of TE biology. This review will discuss the recent improvements that have been made in the computational analysis of TE-derived sequences as well as the areas where such analysis still proves difficult. This article is part of a discussion meeting issue 'Crossroads between transposons and gene regulation'.
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Affiliation(s)
- Kathryn O'Neill
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - David Brocks
- Department of Computer Science and Applied Mathematics, The Weizmann Institute of Science, Rehovot, Israel
| | - Molly Gale Hammell
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
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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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