1
|
Matharu N, Zhao J, Sohota A, Deng L, Hung Y, Li Z, Sims J, Rattanasopha S, Meyer J, Carbone L, Kircher M, Ahituv N. Massively parallel jumping assay decodes Alu retrotransposition activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.16.589814. [PMID: 38659854 PMCID: PMC11042287 DOI: 10.1101/2024.04.16.589814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The human genome contains millions of retrotransposons, several of which could become active due to somatic mutations having phenotypic consequences, including disease. However, it is not thoroughly understood how nucleotide changes in retrotransposons affect their jumping activity. Here, we developed a novel massively parallel jumping assay (MPJA) that can test the jumping potential of thousands of transposons en masse. We generated nucleotide variant library of selected four Alu retrotransposons containing 165,087 different haplotypes and tested them for their jumping ability using MPJA. We found 66,821 unique jumping haplotypes, allowing us to pinpoint domains and variants vital for transposition. Mapping these variants to the Alu-RNA secondary structure revealed stem-loop features that contribute to jumping potential. Combined, our work provides a novel high-throughput assay that assesses the ability of retrotransposons to jump and identifies nucleotide changes that have the potential to reactivate them in the human genome.
Collapse
Affiliation(s)
- Navneet Matharu
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Jingjing Zhao
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Ajuni Sohota
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Linbei Deng
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Yan Hung
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Zizheng Li
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
| | - Jasmine Sims
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Sawitree Rattanasopha
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Josh Meyer
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Lucia Carbone
- Department of Medicine, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
- Division of Genetics, Oregon National Primate Research Center, Beaverton, OR, USA
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
- Department of Medical Informatics and Clinical Epidemiology, Oregon Health and Science University, Portland, OR, USA
| | - Martin Kircher
- Berlin Institute of Health of Health at Charité - Universitätsmedizin Berlin, 10178, Berlin, Germany
- Institute of Human Genetics, University Medical Center Schleswig-Holstein, University of Lübeck, Lübeck, Germany
| | - Nadav Ahituv
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| |
Collapse
|
2
|
Yang L, Metzger GA, Padilla Del Valle R, Delgadillo Rubalcaba D, McLaughlin RN. Evolutionary insights from profiling LINE-1 activity at allelic resolution in a single human genome. EMBO J 2024; 43:112-131. [PMID: 38177314 PMCID: PMC10883270 DOI: 10.1038/s44318-023-00007-y] [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: 09/08/2023] [Revised: 10/18/2023] [Accepted: 11/10/2023] [Indexed: 01/06/2024] Open
Abstract
Transposable elements have created the majority of the sequence in many genomes. In mammals, LINE-1 retrotransposons have been expanding for more than 100 million years as distinct, consecutive lineages; however, the drivers of this recurrent lineage emergence and disappearance are unknown. Most human genome assemblies provide a record of this ancient evolution, but fail to resolve ongoing LINE-1 retrotranspositions. Utilizing the human CHM1 long-read-based haploid assembly, we identified and cloned all full-length, intact LINE-1s, and found 29 LINE-1s with measurable in vitro retrotransposition activity. Among individuals, these LINE-1s varied in their presence, their allelic sequences, and their activity. We found that recently retrotransposed LINE-1s tend to be active in vitro and polymorphic in the population relative to more ancient LINE-1s. However, some rare allelic forms of old LINE-1s retain activity, suggesting older lineages can persist longer than expected. Finally, in LINE-1s with in vitro activity and in vivo fitness, we identified mutations that may have increased replication in ancient genomes and may prove promising candidates for mechanistic investigations of the drivers of LINE-1 evolution and which LINE-1 sequences contribute to human disease.
Collapse
Affiliation(s)
- Lei Yang
- Pacific Northwest Research Institute, Seattle, WA, USA
| | | | - Ricky Padilla Del Valle
- Pacific Northwest Research Institute, Seattle, WA, USA
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA, USA
| | | | - Richard N McLaughlin
- Pacific Northwest Research Institute, Seattle, WA, USA.
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA, USA.
| |
Collapse
|
3
|
Shin W, Mun S, Han K. Human Endogenous Retrovirus-K (HML-2)-Related Genetic Variation: Human Genome Diversity and Disease. Genes (Basel) 2023; 14:2150. [PMID: 38136972 PMCID: PMC10742618 DOI: 10.3390/genes14122150] [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: 10/25/2023] [Revised: 11/23/2023] [Accepted: 11/26/2023] [Indexed: 12/24/2023] Open
Abstract
Human endogenous retroviruses (HERVs) comprise a significant portion of the human genome, making up roughly 8%, a notable comparison to the 2-3% represented by coding sequences. Numerous studies have underscored the critical role and importance of HERVs, highlighting their diverse and extensive influence on the evolution of the human genome and establishing their complex correlation with various diseases. Among HERVs, the HERV-K (HML-2) subfamily has recently attracted significant attention, integrating into the human genome after the divergence between humans and chimpanzees. Its insertion in the human genome has received considerable attention due to its structural and functional characteristics and the time of insertion. Originating from ancient exogenous retroviruses, these elements succeeded in infecting germ cells, enabling vertical transmission and existing as proviruses within the genome. Remarkably, these sequences have retained the capacity to form complete viral sequences, exhibiting activity in transcription and translation. The HERV-K (HML-2) subfamily is the subject of active debate about its potential positive or negative effects on human genome evolution and various pathologies. This review summarizes the variation, regulation, and diseases in human genome evolution arising from the influence of HERV-K (HML-2).
Collapse
Affiliation(s)
- Wonseok Shin
- NGS Clinical Laboratory, Division of Cancer Research, Dankook University Hospital, Cheonan 31116, Republic of Korea;
- Smart Animal Bio Institute, Dankook University, Cheonan 31116, Republic of Korea;
| | - Seyoung Mun
- Smart Animal Bio Institute, Dankook University, Cheonan 31116, Republic of Korea;
- College of Science & Technology, Dankook University, Cheonan 31116, Republic of Korea
- Center for Bio-Medical Engineering Core Facility, Dankook University, Cheonan 31116, Republic of Korea
| | - Kyudong Han
- Smart Animal Bio Institute, Dankook University, Cheonan 31116, Republic of Korea;
- Center for Bio-Medical Engineering Core Facility, Dankook University, Cheonan 31116, Republic of Korea
- Department of Microbiology, College of Science & Technology, Dankook University, Cheonan 31116, Republic of Korea
- Department of Bioconvergence Engineering, Dankook University, Yongin 16890, Republic of Korea
- R&D Center, HuNBiome Co., Ltd., Seoul 08507, Republic of Korea
| |
Collapse
|
4
|
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.
Collapse
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.
| |
Collapse
|
5
|
Koch BF. SARS-CoV-2 and human retroelements: a case for molecular mimicry? BMC Genom Data 2022; 23:27. [PMID: 35395708 PMCID: PMC8992427 DOI: 10.1186/s12863-022-01040-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/16/2022] [Indexed: 01/12/2023] Open
Abstract
Background The factors driving the late phase of COVID-19 are still poorly understood. However, autoimmunity is an evolving theme in COVID-19’s pathogenesis. Additionally, deregulation of human retroelements (RE) is found in many viral infections, and has also been reported in COVID-19. Results Unexpectedly, coronaviruses (CoV) – including SARS-CoV-2 – harbour many RE-identical sequences (up to 35 base pairs), and some of these sequences are part of SARS-CoV-2 epitopes associated to COVID-19 severity. Furthermore, RE are expressed in healthy controls and human cells and become deregulated after SARS-CoV-2 infection, showing mainly changes in long interspersed nuclear element (LINE1) expression, but also in endogenous retroviruses. Conclusion CoV and human RE share coding sequences, which are targeted by antibodies in COVID-19 and thus could induce an autoimmune loop by molecular mimicry. Supplementary Information The online version contains supplementary material available at 10.1186/s12863-022-01040-2.
Collapse
Affiliation(s)
- Benjamin Florian Koch
- Department of Internal Medicine, Nephrology, Goethe University Hospital, Johann Wolfgang Goethe University Frankfurt/Main, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany.
| |
Collapse
|
6
|
Li Piani L, Reschini M, Somigliana E, Ferrari S, Busnelli A, Viganò P, Favero C, Albetti B, Hoxha M, Bollati V. Peripheral mitochondrial DNA, telomere length and DNA methylation as predictors of live birth in in vitro fertilization cycles. PLoS One 2022; 17:e0261591. [PMID: 35073322 PMCID: PMC8786209 DOI: 10.1371/journal.pone.0261591] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 12/03/2021] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE To evaluate whether telomere length (TL), mitochondrial-DNA (mt-DNA) or epigenetic age estimators based on DNA methylation (DNAm) pattern could be considered reliable predictors of in-vitro-fertilization (IVF) success in terms of live birth rate. DESIGN Prospective cohort study. SETTING Infertility Unit of the Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico. PATIENTS 181 women aged 37-39 years who underwent IVF at a single-centre between January 2017 and December 2018. INTERVENTIONS On the day of recruitment, blood samples were collected, and genomic DNA was isolated from white blood cells. TL, mt-DNA and DNAm assessment was performed using quantitative real-time polymerase chain reaction (qPCR). Biological age (DNAm age) was computed as the algorithm based on methylation pattern of five genes. Epigenetic age acceleration was estimated from the residuals of the linear model of epigenetic age regressed on chronological age. Long Interspersed Nuclear Elements (LINE)-1 methylation pattern was used as a surrogate for global DNA methylation. MAIN OUTCOME MEASURES This study investigated whether peripheral TL, mt-DNA and DNAm could predict live birth in IVF cycles. RESULTS TL, mt-DNA and LINE-1 methylation were not associated with IVF success. Conversely, DNAm age resulted significantly lower in women who had a live birth compared to women who did not (36.1 ± 4.2 and 37.3 ± 3.3 years, respectively, p = 0.04). For DNAm age, odds ratio (OR) for live birth per year of age was 0.90 (95%CI: 0.82-0.99, p = 0.036) after adjusting for FSH and antral follicle count (AFC) and 0.90 (95%CI: 0.82-0.99, p = 0.028) after adjusting also for number of oocytes retrieved. A significant association also emerged for epigenetic age acceleration after adjustments (OR = 0.91, 95%CI: 0.83-1.00, p = 0.048). CONCLUSION DNAm age is associated with IVF success but the magnitude of this association is insufficient to claim a clinical use. However, our findings are promising and warrant further investigation. Assessment of biological age using different epigenetic clocks or focusing on different tissues may reveal new predictors of IVF success.
Collapse
Affiliation(s)
- Letizia Li Piani
- Dept of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy
- Infertility Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Marco Reschini
- Infertility Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Edgardo Somigliana
- Dept of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy
- Infertility Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Stefania Ferrari
- Infertility Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Andrea Busnelli
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Milan, Italy
- Division of Gynecology and Reproductive Medicine, Department of Gynecology, IRCCS Humanitas Research Hospital, Fertility Center, Rozzano, Milan, Italy
| | - Paola Viganò
- Infertility Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Chiara Favero
- Dept of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy
| | - Benedetta Albetti
- Dept of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy
| | - Mirjam Hoxha
- Dept of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy
| | - Valentina Bollati
- Dept of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy
| |
Collapse
|
7
|
Liehr T. Repetitive Elements in Humans. Int J Mol Sci 2021; 22:ijms22042072. [PMID: 33669810 PMCID: PMC7922087 DOI: 10.3390/ijms22042072] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/05/2021] [Accepted: 02/15/2021] [Indexed: 12/21/2022] Open
Abstract
Repetitive DNA in humans is still widely considered to be meaningless, and variations within this part of the genome are generally considered to be harmless to the carrier. In contrast, for euchromatic variation, one becomes more careful in classifying inter-individual differences as meaningless and rather tends to see them as possible influencers of the so-called 'genetic background', being able to at least potentially influence disease susceptibilities. Here, the known 'bad boys' among repetitive DNAs are reviewed. Variable numbers of tandem repeats (VNTRs = micro- and minisatellites), small-scale repetitive elements (SSREs) and even chromosomal heteromorphisms (CHs) may therefore have direct or indirect influences on human diseases and susceptibilities. Summarizing this specific aspect here for the first time should contribute to stimulating more research on human repetitive DNA. It should also become clear that these kinds of studies must be done at all available levels of resolution, i.e., from the base pair to chromosomal level and, importantly, the epigenetic level, as well.
Collapse
Affiliation(s)
- Thomas Liehr
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Am Klinikum 1, D-07747 Jena, Germany
| |
Collapse
|
8
|
Restriction Enzyme Based Enriched L1Hs Sequencing (REBELseq): A Scalable Technique for Detection of Ta Subfamily L1Hs in the Human Genome. G3-GENES GENOMES GENETICS 2020; 10:1647-1655. [PMID: 32132168 PMCID: PMC7202019 DOI: 10.1534/g3.119.400613] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Long interspersed element-1 retrotransposons (LINE-1 or L1) are ∼6 kb mobile DNA elements implicated in the origins of many Mendelian and complex diseases. The actively retrotransposing L1s are mostly limited to the L1 human specific (L1Hs) transcriptional active (Ta) subfamily. In this manuscript, we present REBELseq as a method for the construction of Ta subfamily L1Hs-enriched next-generation sequencing libraries and bioinformatic identification. REBELseq was performed on DNA isolated from NeuN+ neuronal nuclei from postmortem brain samples of 177 individuals and empirically-driven bioinformatic and experimental cutoffs were established. Putative L1Hs insertions passing bioinformatics cutoffs were experimentally validated. REBELseq reliably identified both known and novel Ta subfamily L1Hs insertions distributed throughout the genome. Differences in the proportion of individuals possessing a given reference or non-reference retrotransposon insertion were identified. We conclude that REBELseq is an unbiased, whole genome approach to the amplification and detection of Ta subfamily L1Hs retrotransposons.
Collapse
|
9
|
Loh JW, Ha H, Lin T, Sun N, Burns KH, Xing J. Integrated Mobile Element Scanning (ME-Scan) method for identifying multiple types of polymorphic mobile element insertions. Mob DNA 2020; 11:12. [PMID: 32110248 PMCID: PMC7035633 DOI: 10.1186/s13100-020-00207-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 02/14/2020] [Indexed: 01/29/2023] Open
Abstract
Background Mobile elements are ubiquitous components of mammalian genomes and constitute more than half of the human genome. Polymorphic mobile element insertions (pMEIs) are a major source of human genomic variation and are gaining research interest because of their involvement in gene expression regulation, genome integrity, and disease. Results Building on our previous Mobile Element Scanning (ME-Scan) protocols, we developed an integrated ME-Scan protocol to identify three major active families of human mobile elements, AluYb, L1HS, and SVA. This approach selectively amplifies insertion sites of currently active retrotransposons for Illumina sequencing. By pooling the libraries together, we can identify pMEIs from all three mobile element families in one sequencing run. To demonstrate the utility of the new ME-Scan protocol, we sequenced 12 human parent-offspring trios. Our results showed high sensitivity (> 90%) and accuracy (> 95%) of the protocol for identifying pMEIs in the human genome. In addition, we also tested the feasibility of identifying somatic insertions using the protocol. Conclusions The integrated ME-Scan protocol is a cost-effective way to identify novel pMEIs in the human genome. In addition, by developing the protocol to detect three mobile element families, we demonstrate the flexibility of the ME-Scan protocol. We present instructions for the library design, a sequencing protocol, and a computational pipeline for downstream analyses as a complete framework that will allow researchers to easily adapt the ME-Scan protocol to their own projects in other genomes.
Collapse
Affiliation(s)
- Jui Wan Loh
- 1Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ 08854 USA
| | - Hongseok Ha
- 1Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ 08854 USA.,2Human Genetic Institute of New Jersey, Rutgers, the State University of New Jersey, Piscataway, 08854 NJ USA
| | - Timothy Lin
- 1Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ 08854 USA
| | - Nawei Sun
- 1Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ 08854 USA.,2Human Genetic Institute of New Jersey, Rutgers, the State University of New Jersey, Piscataway, 08854 NJ USA
| | - Kathleen H Burns
- 3Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, 21205 MD USA
| | - Jinchuan Xing
- 1Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ 08854 USA.,2Human Genetic Institute of New Jersey, Rutgers, the State University of New Jersey, Piscataway, 08854 NJ USA
| |
Collapse
|
10
|
McKerrow W, Tang Z, Steranka JP, Payer LM, Boeke JD, Keefe D, Fenyö D, Burns KH, Liu C. Human transposon insertion profiling by sequencing (TIPseq) to map LINE-1 insertions in single cells. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190335. [PMID: 32075555 PMCID: PMC7061987 DOI: 10.1098/rstb.2019.0335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Long interspersed element-1 (LINE-1, L1) sequences, which comprise about 17% of human genome, are the product of one of the most active types of mobile DNAs in modern humans. LINE-1 insertion alleles can cause inherited and de novo genetic diseases, and LINE-1-encoded proteins are highly expressed in some cancers. Genome-wide LINE-1 mapping in single cells could be useful for defining somatic and germline retrotransposition rates, and for enabling studies to characterize tumour heterogeneity, relate insertions to transcriptional and epigenetic effects at the cellular level, or describe cellular phylogenies in development. Our laboratories have reported a genome-wide LINE-1 insertion site mapping method for bulk DNA, named transposon insertion profiling by sequencing (TIPseq). There have been significant barriers applying LINE-1 mapping to single cells, owing to the chimeric artefacts and features of repetitive sequences. Here, we optimize a modified TIPseq protocol and show its utility for LINE-1 mapping in single lymphoblastoid cells. Results from single-cell TIPseq experiments compare well to known LINE-1 insertions found by whole-genome sequencing and TIPseq on bulk DNA. Among the several approaches we tested, whole-genome amplification by multiple displacement amplification followed by restriction enzyme digestion, vectorette ligation and LINE-1-targeted PCR had the best assay performance. This article is part of a discussion meeting issue 'Crossroads between transposons and gene regulation'.
Collapse
Affiliation(s)
- Wilson McKerrow
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, USA
| | - Zuojian Tang
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, USA
| | - Jared P Steranka
- Department of Pathology, Johns Hopkins University School of Medicine, 733N Broadway, Baltimore, MD 21205, USA
| | - Lindsay M Payer
- Department of Pathology, Johns Hopkins University School of Medicine, 733N Broadway, Baltimore, MD 21205, USA
| | - Jef D Boeke
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, USA
| | - David Keefe
- Department of Obstetrics and Gynecology, New York University Langone School of Medicine, 462 First Avenue, New York, NY 10016, USA.,Department of Cell Biology, New York University Langone School of Medicine, 462 First Avenue, New York, NY 10016, USA
| | - David Fenyö
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, USA
| | - Kathleen H Burns
- Department of Pathology, Johns Hopkins University School of Medicine, 733N Broadway, Baltimore, MD 21205, USA.,McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, 733N Broadway, Baltimore, MD 21205, USA.,High Throughput (HiT) Biology Center, Johns Hopkins University School of Medicine, 733N Broadway, Baltimore, MD 21205, USA.,Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, 401N Broadway, Baltimore, MD 21231, USA
| | - Chunhong Liu
- Department of Pathology, Johns Hopkins University School of Medicine, 733N Broadway, Baltimore, MD 21205, USA
| |
Collapse
|
11
|
Shin W, Mun S, Kim J, Lee W, Park DG, Choi S, Lee TY, Cha S, Han K. Novel Discovery of LINE-1 in a Korean Individual by a Target Enrichment Method. Mol Cells 2019; 42:87-95. [PMID: 30699287 PMCID: PMC6354063 DOI: 10.14348/molcells.2018.0351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 10/10/2018] [Accepted: 10/26/2018] [Indexed: 11/27/2022] Open
Abstract
Long interspersed element-1 (LINE-1 or L1) is an autonomous retrotransposon, which is capable of inserting into a new region of genome. Previous studies have reported that these elements lead to genomic variations and altered functions by affecting gene expression and genetic networks. Mounting evidence strongly indicates that genetic diseases or various cancers can occur as a result of retrotransposition events that involve L1s. Therefore, the development of methodologies to study the structural variations and interpersonal insertion polymorphisms by L1 element-associated changes in an individual genome is invaluable. In this study, we applied a systematic approach to identify human-specific L1s (i.e., L1Hs) through the bioinformatics analysis of high-throughput next-generation sequencing data. We identified 525 candidates that could be inferred to carry non-reference L1Hs in a Korean individual genome (KPGP9). Among them, we randomly selected 40 candidates and validated that approximately 92.5% of non-reference L1Hs were inserted into a KPGP9 genome. In addition, unlike conventional methods, our relatively simple and expedited approach was highly reproducible in confirming the L1 insertions. Taken together, our findings strongly support that the identification of non-reference L1Hs by our novel target enrichment method demonstrates its future application to genomic variation studies on the risk of cancer and genetic disorders.
Collapse
Affiliation(s)
- Wonseok Shin
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 31116,
Korea
| | - Seyoung Mun
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 31116,
Korea
| | - Junse Kim
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 31116,
Korea
| | - Wooseok Lee
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 31116,
Korea
| | - Dong-Guk Park
- Department of Surgery, Dankook University College of Medicine, Cheonan 31116,
Korea
| | - Seungkyu Choi
- Department of Pathology, Dankook University College of Medicine, Cheonan 31116,
Korea
| | - Tae Yoon Lee
- Department of Technology Education and Department of Biomedical Engineering, Chungnam National University, Daejeon 34134,
Korea
| | - Seunghee Cha
- Department of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, FL 32610,
USA
| | - Kyudong Han
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 31116,
Korea
| |
Collapse
|
12
|
|
13
|
Kvikstad EM, Piazza P, Taylor JC, Lunter G. A high throughput screen for active human transposable elements. BMC Genomics 2018; 19:115. [PMID: 29390960 PMCID: PMC5796560 DOI: 10.1186/s12864-018-4485-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 01/16/2018] [Indexed: 11/30/2022] Open
Abstract
Background Transposable elements (TEs) are mobile genetic sequences that randomly propagate within their host’s genome. This mobility has the potential to affect gene transcription and cause disease. However, TEs are technically challenging to identify, which complicates efforts to assess the impact of TE insertions on disease. Here we present a targeted sequencing protocol and computational pipeline to identify polymorphic and novel TE insertions using next-generation sequencing: TE-NGS. The method simultaneously targets the three subfamilies that are responsible for the majority of recent TE activity (L1HS, AluYa5/8, and AluYb8/9) thereby obviating the need for multiple experiments and reducing the amount of input material required. Results Here we describe the laboratory protocol and detection algorithm, and a benchmark experiment for the reference genome NA12878. We demonstrate a substantial enrichment for on-target fragments, and high sensitivity and precision to both reference and NA12878-specific insertions. We report 17 previously unreported loci for this individual which are supported by orthogonal long-read evidence, and we identify 1470 polymorphic and novel TEs in 12 additional samples that were previously undocumented in databases of insertion polymorphisms. Conclusions We anticipate that future applications of TE-NGS alongside exome sequencing of patients with sporadic disease will reduce the number of unresolved cases, and improve estimates of the contribution of TEs to human genetic disease. Electronic supplementary material The online version of this article (10.1186/s12864-018-4485-4) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Erika M Kvikstad
- Wellcome Trust Centre for Human Genetics, Oxford, UK. .,National Institute for Health Research Comprehensive Biomedical Research Centre, Oxford, UK.
| | - Paolo Piazza
- Wellcome Trust Centre for Human Genetics, Oxford, UK.,Department of Medicine, Imperial College London, London, UK
| | - Jenny C Taylor
- Wellcome Trust Centre for Human Genetics, Oxford, UK.,National Institute for Health Research Comprehensive Biomedical Research Centre, Oxford, UK
| | - Gerton Lunter
- Wellcome Trust Centre for Human Genetics, Oxford, UK
| |
Collapse
|
14
|
Boissinot S, Sookdeo A. The Evolution of LINE-1 in Vertebrates. Genome Biol Evol 2018; 8:3485-3507. [PMID: 28175298 PMCID: PMC5381506 DOI: 10.1093/gbe/evw247] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2016] [Indexed: 12/21/2022] Open
Abstract
The abundance and diversity of the LINE-1 (L1) retrotransposon differ greatly among vertebrates. Mammalian genomes contain hundreds of thousands L1s that have accumulated since the origin of mammals. A single group of very similar elements is active at a time in mammals, thus a single lineage of active families has evolved in this group. In contrast, non-mammalian genomes (fish, amphibians, reptiles) harbor a large diversity of concurrently transposing families, which are all represented by very small number of recently inserted copies. Why the pattern of diversity and abundance of L1 is so different among vertebrates remains unknown. To address this issue, we performed a detailed analysis of the evolution of active L1 in 14 mammals and in 3 non-mammalian vertebrate model species. We examined the evolution of base composition and codon bias, the general structure, and the evolution of the different domains of L1 (5′UTR, ORF1, ORF2, 3′UTR). L1s differ substantially in length, base composition, and structure among vertebrates. The most variation is found in the 5′UTR, which is longer in amniotes, and in the ORF1, which tend to evolve faster in mammals. The highly divergent L1 families of lizard, frog, and fish share species-specific features suggesting that they are subjected to the same functional constraints imposed by their host. The relative conservation of the 5′UTR and ORF1 in non-mammalian vertebrates suggests that the repression of transposition by the host does not act in a sequence-specific manner and did not result in an arms race, as is observed in mammals.
Collapse
|
15
|
Servant G, Streva VA, Deininger PL. Transcription coupled repair and biased insertion of human retrotransposon L1 in transcribed genes. Mob DNA 2017; 8:18. [PMID: 29225704 PMCID: PMC5717806 DOI: 10.1186/s13100-017-0100-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 11/06/2017] [Indexed: 11/26/2022] Open
Abstract
Background L1 retrotransposons inserted within genes in the human genome show a strong bias against sense orientation with respect to the gene. One suggested explanation for this observation was the possibility that L1 inserted randomly, but that there was negative selection against sense-oriented insertions. However, multiple studies have now found that de novo and polymorphic L1 insertions, which have little opportunity for selection to act, also show the same bias. Results Here we show that the transcription-coupled sub-pathway of nucleotide excision repair does not affect the overall rate of insertion of L1 elements, which is in contrast with the regulation by the global sub-pathway of nucleotide excision repair. The transcription-coupled subpathway does cause a strong bias against insertion in the sense orientation relative to genes. Conclusions This suggests that a major portion of the L1 orientation bias might be generated during the process of insertion through the action of transcription-coupled nucleotide excision repair. Electronic supplementary material The online version of this article (10.1186/s13100-017-0100-5) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Geraldine Servant
- Tulane University, Tulane Cancer Center and the Department of Epidemiology, 1430 Tulane Ave, New Orleans, LA 70112 USA
| | - Vincent A Streva
- Tulane University, Tulane Cancer Center and the Department of Epidemiology, 1430 Tulane Ave, New Orleans, LA 70112 USA.,Present Address: Division of Infectious Diseases, Boston Children's Hospital and Harvard Medical School, 300 Longwood Ave, Boston, MA 02115 USA
| | - Prescott L Deininger
- Tulane University, Tulane Cancer Center and the Department of Epidemiology, 1430 Tulane Ave, New Orleans, LA 70112 USA.,Tulane Cancer Center, SL66, Tulane University Health Sciences Center, 1430 Tulane Ave., New Orleans, LA 70112 USA
| |
Collapse
|
16
|
Deininger P, Morales ME, White TB, Baddoo M, Hedges DJ, Servant G, Srivastav S, Smither ME, Concha M, DeHaro DL, Flemington EK, Belancio VP. A comprehensive approach to expression of L1 loci. Nucleic Acids Res 2017; 45:e31. [PMID: 27899577 PMCID: PMC5389711 DOI: 10.1093/nar/gkw1067] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 11/09/2016] [Indexed: 11/14/2022] Open
Abstract
L1 elements represent the only currently active, autonomous retrotransposon in the human genome, and they make major contributions to human genetic instability. The vast majority of the 500 000 L1 elements in the genome are defective, and only a relatively few can contribute to the retrotransposition process. However, there is currently no comprehensive approach to identify the specific loci that are actively transcribed separate from the excess of L1-related sequences that are co-transcribed within genes. We have developed RNA-Seq procedures, as well as a 1200 bp 5΄ RACE product coupled with PACBio sequencing that can identify the specific L1 loci that contribute most of the L1-related RNA reads. At least 99% of L1-related sequences found in RNA do not arise from the L1 promoter, instead representing pieces of L1 incorporated in other cellular RNAs. In any given cell type a relatively few active L1 loci contribute to the 'authentic' L1 transcripts that arise from the L1 promoter, with significantly different loci seen expressed in different tissues.
Collapse
Affiliation(s)
- Prescott Deininger
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA.,Department of Epidemiology, Tulane University, New Orleans, LA 70112, USA
| | - Maria E Morales
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA
| | - Travis B White
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA
| | - Melody Baddoo
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA
| | - Dale J Hedges
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA
| | | | - Sudesh Srivastav
- Department of Structural and Cellular Biology, Tulane University, New Orleans, LA 70112, USA
| | | | - Monica Concha
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA.,Department of Biostatistics and Bioinformatics, Tulane University, New Orleans, LA 70112, USA
| | - Dawn L DeHaro
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA.,Department of Pathology, Tulane University, New Orleans, LA 70112, USA
| | - Erik K Flemington
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA.,Department of Biostatistics and Bioinformatics, Tulane University, New Orleans, LA 70112, USA
| | - Victoria P Belancio
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA.,Department of Pathology, Tulane University, New Orleans, LA 70112, USA
| |
Collapse
|
17
|
Abstract
Transposable elements give rise to interspersed repeats, sequences that comprise most of our genomes. These mobile DNAs have been historically underappreciated - both because they have been presumed to be unimportant, and because their high copy number and variability pose unique technical challenges. Neither impediment now seems steadfast. Interest in the human mobilome has never been greater, and methods enabling its study are maturing at a fast pace. This Review describes the activity of transposable elements in human cancers, particularly long interspersed element-1 (LINE-1). LINE-1 sequences are self-propagating, protein-coding retrotransposons, and their activity results in somatically acquired insertions in cancer genomes. Altered expression of transposable elements and animation of genomic LINE-1 sequences appear to be hallmarks of cancer, and can be responsible for driving mutations in tumorigenesis.
Collapse
Affiliation(s)
- Kathleen H Burns
- Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| |
Collapse
|
18
|
Transposable elements in cancer. NATURE REVIEWS. CANCER 2017. [PMID: 28642606 DOI: 10.1038/nrc.2017.35+[doi]] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Transposable elements give rise to interspersed repeats, sequences that comprise most of our genomes. These mobile DNAs have been historically underappreciated - both because they have been presumed to be unimportant, and because their high copy number and variability pose unique technical challenges. Neither impediment now seems steadfast. Interest in the human mobilome has never been greater, and methods enabling its study are maturing at a fast pace. This Review describes the activity of transposable elements in human cancers, particularly long interspersed element-1 (LINE-1). LINE-1 sequences are self-propagating, protein-coding retrotransposons, and their activity results in somatically acquired insertions in cancer genomes. Altered expression of transposable elements and animation of genomic LINE-1 sequences appear to be hallmarks of cancer, and can be responsible for driving mutations in tumorigenesis.
Collapse
|
19
|
Integration site selection by retroviruses and transposable elements in eukaryotes. Nat Rev Genet 2017; 18:292-308. [PMID: 28286338 DOI: 10.1038/nrg.2017.7] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Transposable elements and retroviruses are found in most genomes, can be pathogenic and are widely used as gene-delivery and functional genomics tools. Exploring whether these genetic elements target specific genomic sites for integration and how this preference is achieved is crucial to our understanding of genome evolution, somatic genome plasticity in cancer and ageing, host-parasite interactions and genome engineering applications. High-throughput profiling of integration sites by next-generation sequencing, combined with large-scale genomic data mining and cellular or biochemical approaches, has revealed that the insertions are usually non-random. The DNA sequence, chromatin and nuclear context, and cellular proteins cooperate in guiding integration in eukaryotic genomes, leading to a remarkable diversity of insertion site distribution and evolutionary strategies.
Collapse
|
20
|
Ardeljan D, Taylor MS, Ting DT, Burns KH. The Human Long Interspersed Element-1 Retrotransposon: An Emerging Biomarker of Neoplasia. Clin Chem 2017; 63:816-822. [PMID: 28188229 DOI: 10.1373/clinchem.2016.257444] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 11/22/2016] [Indexed: 02/06/2023]
Abstract
BACKGROUND A large portion of intronic and intergenic space in our genome consists of repeated sequences. One of the most prevalent is the long interspersed element-1 (LINE-1, L1) mobile DNA. LINE-1 is rightly receiving increasing interest as a cancer biomarker. CONTENT Intact LINE-1 elements are self-propagating. They code for RNA and proteins that function to make more copies of the genomic element. Our current understanding is that this process is repressed in most normal cells, but that LINE-1 expression is a hallmark of many types of malignancy. Here, we will consider features of cancer cells when cellular defense mechanisms repressing LINE-1 go awry. We will review evidence that genomic LINE-1 methylation, LINE-1-encoded RNAs, and LINE-1 ORF1p (open reading frame 1 protein) may be useful in cancer diagnosis. SUMMARY The repetitive and variable nature of LINE-1 DNA sequences poses unique challenges to studying them, but recent advances in reagents and next generation sequencing present opportunities to characterize LINE-1 expression and activity in cancers and to identify clinical applications.
Collapse
Affiliation(s)
- Daniel Ardeljan
- McKusick-Nathans Institute of Genetic Medicine (IGM) and.,Medical Scientist Training Program (MSTP), Johns Hopkins University School of Medicine, Baltimore, MD
| | - Martin S Taylor
- Department of Pathology, Massachusetts General Hospital, Boston, MA
| | - David T Ting
- Department of Medicine and the Massachusetts General Hospital Cancer Center, Boston, MA
| | - Kathleen H Burns
- McKusick-Nathans Institute of Genetic Medicine (IGM) and .,Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD
| |
Collapse
|
21
|
Human transposon insertion profiling: Analysis, visualization and identification of somatic LINE-1 insertions in ovarian cancer. Proc Natl Acad Sci U S A 2017; 114:E733-E740. [PMID: 28096347 DOI: 10.1073/pnas.1619797114] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mammalian genomes are replete with interspersed repeats reflecting the activity of transposable elements. These mobile DNAs are self-propagating, and their continued transposition is a source of both heritable structural variation as well as somatic mutation in human genomes. Tailored approaches to map these sequences are useful to identify insertion alleles. Here, we describe in detail a strategy to amplify and sequence long interspersed element-1 (LINE-1, L1) retrotransposon insertions selectively in the human genome, transposon insertion profiling by next-generation sequencing (TIPseq). We also report the development of a machine-learning-based computational pipeline, TIPseqHunter, to identify insertion sites with high precision and reliability. We demonstrate the utility of this approach to detect somatic retrotransposition events in high-grade ovarian serous carcinoma.
Collapse
|
22
|
Cook PR, Tabor GT. Deciphering fact from artifact when using reporter assays to investigate the roles of host factors on L1 retrotransposition. Mob DNA 2016; 7:23. [PMID: 27895722 PMCID: PMC5120415 DOI: 10.1186/s13100-016-0079-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Accepted: 11/04/2016] [Indexed: 12/24/2022] Open
Abstract
Background The Long INterspersed Element-1 (L1, LINE-1) is the only autonomous mobile DNA element in humans and has generated as much as half of the genome. Due to increasing clinical interest in the roles of L1 in cancer, embryogenesis and neuronal development, it has become a priority to understand L1-host interactions and identify host factors required for its activity. Apropos to this, we recently reported that L1 retrotransposition in HeLa cells requires phosphorylation of the L1 protein ORF1p at motifs targeted by host cell proline-directed protein kinases (PDPKs), which include the family of mitogen-activated protein kinases (MAPKs). Using two engineered L1 reporter assays, we continued our investigation into the roles of MAPKs in L1 activity. Results We found that the MAPK p38δ phosphorylated ORF1p on three of its four PDPK motifs required for L1 activity. In addition, we found that a constitutively active p38δ mutant appeared to promote L1 retrotransposition in HeLa cells. However, despite the consistency of these findings with our earlier work, we identified some technical concerns regarding the experimental methodology. Specifically, we found that exogenous expression of p38δ appeared to affect at least one heterologous promoter in an engineered L1 reporter, as well as generate opposing effects on two different reporters. We also show that two commercially available non-targeting control (NTC) siRNAs elicit drastically different effects on the apparent retrotransposition reported by both L1 assays, which raises concerns about the use of NTCs as normalizing controls. Conclusions Engineered L1 reporter assays have been invaluable for determining the functions and critical residues of L1 open reading frames, as well as elucidating many aspects of L1 replication. However, our results suggest that caution is required when interpreting data obtained from L1 reporters used in conjunction with exogenous gene expression or siRNA.
Collapse
Affiliation(s)
- Pamela R Cook
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Drive, Bethesda, MD 20892 USA
| | - G Travis Tabor
- National Institute of Child Health and Human Development, National Institutes of Health, 35 Convent Drive, Bethesda, MD 20892 USA
| |
Collapse
|
23
|
The Nucleotide Excision Repair Pathway Limits L1 Retrotransposition. Genetics 2016; 205:139-153. [PMID: 28049704 PMCID: PMC5223499 DOI: 10.1534/genetics.116.188680] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 10/30/2016] [Indexed: 12/25/2022] Open
Abstract
Long interspersed elements 1 (L1) are active mobile elements that constitute almost 17% of the human genome. They amplify through a “copy-and-paste” mechanism termed retrotransposition, and de novo insertions related to these elements have been reported to cause 0.2% of genetic diseases. Our previous data demonstrated that the endonuclease complex ERCC1-XPF, which cleaves a 3′ DNA flap structure, limits L1 retrotransposition. Although the ERCC1-XPF endonuclease participates in several different DNA repair pathways, such as single-strand annealing, or in telomere maintenance, its recruitment to DNA lesions is best characterized in the nucleotide excision repair (NER) pathway. To determine if the NER pathway prevents the insertion of retroelements in the genome, we monitored the retrotransposition efficiencies of engineered L1 elements in NER-deficient cells and in their complemented versions. Core proteins of the NER pathway, XPD and XPA, and the lesion binding protein, XPC, are involved in limiting L1 retrotransposition. In addition, sequence analysis of recovered de novo L1 inserts and their genomic locations in NER-deficient cells demonstrated the presence of abnormally large duplications at the site of insertion, suggesting that NER proteins may also play a role in the normal L1 insertion process. Here, we propose new functions for the NER pathway in the maintenance of genome integrity: limitation of insertional mutations caused by retrotransposons and the prevention of potentially mutagenic large genomic duplications at the site of retrotransposon insertion events.
Collapse
|
24
|
Heavy metal and junk DNA. Mob Genet Elements 2016; 6:e1234428. [PMID: 27777812 DOI: 10.1080/2159256x.2016.1234428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/06/2016] [Indexed: 10/21/2022] Open
|
25
|
Belancio VP. LINE-1 activity as molecular basis for genomic instability associated with light exposure at night. Mob Genet Elements 2015; 5:1-5. [PMID: 26442182 DOI: 10.1080/2159256x.2015.1037416] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 03/24/2015] [Accepted: 03/26/2015] [Indexed: 12/29/2022] Open
Abstract
The original hypothesis that exposure to light at night increases risk of breast cancer via suppression of nocturnal melatonin production was proposed over 2 decades ago. In 2007, shift work that involves circadian disruption has been recognized by the World Health Organization as a probable human carcinogen. Our discovery of melatonin-dependent regulation of LINE-1 retrotransposon expression and mobilization is the latest addition to the list of cellular genes and processes that are affected by light exposure at night. This finding establishes an unexpected health relevant connection between this endogenous DNA damaging agent and environmental light exposure. It also offers an appealing hypothesis pertaining to the origin of genomic instability in the genomes of individuals with light at night- or age-associated disruption of melatonin signaling.
Collapse
Affiliation(s)
- Victoria P Belancio
- Department of Structural and Cellular Biology; Tulane Cancer Center; Tulane Cancer for Aging; Tulane Center for Circadian Biology; Tulane University ; New Orleans, LA USA
| |
Collapse
|