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D'Ordine AM, Jogl G, Sedivy JM. Identification and characterization of small molecule inhibitors of the LINE-1 retrotransposon endonuclease. Nat Commun 2024; 15:3883. [PMID: 38719805 PMCID: PMC11078990 DOI: 10.1038/s41467-024-48066-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 04/18/2024] [Indexed: 05/12/2024] Open
Abstract
The long interspersed nuclear element-1 (LINE-1 or L1) retrotransposon is the only active autonomously replicating retrotransposon in the human genome. L1 harms the cell by inserting new copies, generating DNA damage, and triggering inflammation. Therefore, L1 inhibition could be used to treat many diseases associated with these processes. Previous research has focused on inhibition of the L1 reverse transcriptase due to the prevalence of well-characterized inhibitors of related viral enzymes. Here we present the L1 endonuclease as another target for reducing L1 activity. We characterize structurally diverse small molecule endonuclease inhibitors using computational, biochemical, and biophysical methods. We also show that these inhibitors reduce L1 retrotransposition, L1-induced DNA damage, and inflammation reinforced by L1 in senescent cells. These inhibitors could be used for further pharmacological development and as tools to better understand the life cycle of this element and its impact on disease processes.
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Affiliation(s)
- Alexandra M D'Ordine
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
- Center on the Biology of Aging, Brown University, Providence, RI, USA
| | - Gerwald Jogl
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA.
- Center on the Biology of Aging, Brown University, Providence, RI, USA.
| | - John M Sedivy
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA.
- Center on the Biology of Aging, Brown University, Providence, RI, USA.
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Baril T, Galbraith J, Hayward A. Earl Grey: A Fully Automated User-Friendly Transposable Element Annotation and Analysis Pipeline. Mol Biol Evol 2024; 41:msae068. [PMID: 38577785 PMCID: PMC11003543 DOI: 10.1093/molbev/msae068] [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: 11/24/2023] [Revised: 02/20/2024] [Accepted: 03/22/2024] [Indexed: 04/06/2024] Open
Abstract
Transposable elements (TEs) are major components of eukaryotic genomes and are implicated in a range of evolutionary processes. Yet, TE annotation and characterization remain challenging, particularly for nonspecialists, since existing pipelines are typically complicated to install, run, and extract data from. Current methods of automated TE annotation are also subject to issues that reduce overall quality, particularly (i) fragmented and overlapping TE annotations, leading to erroneous estimates of TE count and coverage, and (ii) repeat models represented by short sections of total TE length, with poor capture of 5' and 3' ends. To address these issues, we present Earl Grey, a fully automated TE annotation pipeline designed for user-friendly curation and annotation of TEs in eukaryotic genome assemblies. Using nine simulated genomes and an annotation of Drosophila melanogaster, we show that Earl Grey outperforms current widely used TE annotation methodologies in ameliorating the issues mentioned above while scoring highly in benchmarking for TE annotation and classification and being robust across genomic contexts. Earl Grey provides a comprehensive and fully automated TE annotation toolkit that provides researchers with paper-ready summary figures and outputs in standard formats compatible with other bioinformatics tools. Earl Grey has a modular format, with great scope for the inclusion of additional modules focused on further quality control and tailored analyses in future releases.
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Affiliation(s)
- Tobias Baril
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - James Galbraith
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Alex Hayward
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
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Zehrbach NM, Oh N, Ishak CA. Insights into LINE-1 reverse transcription guide therapy development. Trends Cancer 2024; 10:286-288. [PMID: 38499453 DOI: 10.1016/j.trecan.2024.02.010] [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: 01/15/2024] [Accepted: 02/29/2024] [Indexed: 03/20/2024]
Abstract
Subsets of long interspersed nuclear element 1 (LINE-1) retrotransposons can 'retrotranspose' throughout the human genome at a cost to host cell fitness, as observed in some cancers. Pharmacological inhibition of LINE-1 retrotransposition requires a comprehensive understanding of the LINE-1 ORF2p reverse transcriptase. Two recent publications, by Thawani et al. and Baldwin et al., report structures of LINE-1 ORF2p and address long-standing mechanistic gaps regarding LINE-1 retrotransposition. Both studies will be critical to design new specific inhibitors of the LINE-1 ORF2p reverse transcriptase.
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Affiliation(s)
- Nicholas M Zehrbach
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Nakyung Oh
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Charles A Ishak
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX, USA; Department of Gynecologic Oncology and Reproductive Medicine, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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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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Chow TW, Raupp M, Reynolds MW, Li S, Kaeser GE, Chun J. Nucleoside Reverse Transcriptase Inhibitor Exposure Is Associated with Lower Alzheimer's Disease Risk: A Retrospective Cohort Proof-of-Concept Study. Pharmaceuticals (Basel) 2024; 17:408. [PMID: 38675371 PMCID: PMC11053431 DOI: 10.3390/ph17040408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/02/2024] [Accepted: 03/19/2024] [Indexed: 04/28/2024] Open
Abstract
Brain somatic gene recombination (SGR) and the endogenous reverse transcriptases (RTs) that produce it have been implicated in the etiology of Alzheimer's disease (AD), suggesting RT inhibitors as novel prophylactics or therapeutics. This retrospective, proof-of-concept study evaluated the incidence of AD in people with human immunodeficiency virus (HIV) with or without exposure to nucleoside RT inhibitors (NRTIs) using de-identified medical claims data. Eligible participants were aged ≥60 years, without pre-existing AD diagnoses, and pursued medical services in the United States from October 2015 to September 2016. Cohorts 1 (N = 46,218) and 2 (N = 32,923) had HIV. Cohort 1 had prescription claims for at least one NRTI within the exposure period; Cohort 2 did not. Cohort 3 (N = 150,819) had medical claims for the common cold without evidence of HIV or antiretroviral therapy. The cumulative incidence of new AD cases over the ensuing 2.75-year observation period was lowest in patients with NRTI exposure and highest in controls. Age- and sex-adjusted hazard ratios showed a significantly decreased risk for AD in Cohort 1 compared with Cohorts 2 (HR 0.88, p < 0.05) and 3 (HR 0.84, p < 0.05). Sub-grouping identified a decreased AD risk in patients with NRTI exposure but without protease inhibitor (PI) exposure. Prospective clinical trials and the development of next-generation agents targeting brain RTs are warranted.
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Affiliation(s)
- Tiffany W. Chow
- IQVIA, Durham, NC 27703, USA; (T.W.C.); (M.R.)
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mark Raupp
- IQVIA, Durham, NC 27703, USA; (T.W.C.); (M.R.)
| | | | - Siying Li
- IQVIA, Durham, NC 27703, USA; (T.W.C.); (M.R.)
| | - Gwendolyn E. Kaeser
- Center for Genetic Disorders and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Jerold Chun
- Center for Genetic Disorders and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
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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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Saha K, Nielsen GI, Nandani R, Kong L, Ye P, An W. YY1 is a transcriptional activator of mouse LINE-1 Tf subfamily. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.03.573552. [PMID: 38260579 PMCID: PMC10802269 DOI: 10.1101/2024.01.03.573552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Long interspersed element type 1 (LINE-1, L1) is an active autonomous transposable element (TE) in the human genome. The first step of L1 replication is transcription, which is controlled by an internal RNA polymerase II promoter in the 5' untranslated region (UTR) of a full-length L1. It has been shown that transcription factor YY1 binds to a conserved sequence motif at the 5' end of the human L1 5'UTR and dictates where transcription initiates but not the level of transcription. Putative YY1-binding motifs have been predicted in the 5'UTRs of two distinct mouse L1 subfamilies, Tf and Gf. Using site-directed mutagenesis, in vitro binding, and gene knockdown assays, we experimentally tested the role of YY1 in mouse L1 transcription. Our results indicate that Tf, but not Gf subfamily, harbors functional YY1-binding sites in its 5'UTR monomers. In contrast to its role in human L1, YY1 functions as a transcriptional activator for the mouse Tf subfamily. Furthermore, YY1-binding motifs are solely responsible for the synergistic interaction between monomers, consistent with a model wherein distant monomers act as enhancers for mouse L1 transcription. The abundance of YY1-binding sites in Tf elements also raise important implications for gene regulation at the genomic level.
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Affiliation(s)
- Karabi Saha
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007, USA
| | - Grace I. Nielsen
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007, USA
| | - Raj Nandani
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007, USA
| | - Lingqi Kong
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007, USA
| | - Ping Ye
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007, USA
| | - Wenfeng An
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD 57007, USA
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