1
|
Jin SW, Seong Y, Yoon D, Kwon YS, Song H. Dissolution of ribonucleoprotein condensates by the embryonic stem cell protein L1TD1. Nucleic Acids Res 2024; 52:3310-3326. [PMID: 38165001 PMCID: PMC11014241 DOI: 10.1093/nar/gkad1244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 11/22/2023] [Accepted: 12/18/2023] [Indexed: 01/03/2024] Open
Abstract
L1TD1 is a cytoplasmic RNA-binding protein specifically expressed in pluripotent stem cells and, unlike its mouse ortholog, is essential for the maintenance of stemness in human cells. Although L1TD1 is the only known protein-coding gene domesticated from a LINE-1 (L1) retroelement, the functional legacy of its ancestral protein, ORF1p of L1, and how it is manifested in L1TD1 are still unknown. Here, we determined RNAs associated with L1TD1 and found that, like ORF1p, L1TD1 binds L1 RNAs and localizes to high-density ribonucleoprotein (RNP) condensates. Unexpectedly, L1TD1 enhanced the translation of a subset of mRNAs enriched in the condensates. L1TD1 depletion promoted the formation of stress granules in embryonic stem cells. In HeLa cells, ectopically expressed L1TD1 facilitated the dissolution of stress granules and granules formed by pathological mutations of TDP-43 and FUS. The glutamate-rich domain and the ORF1-homology domain of L1TD1 facilitated dispersal of the RNPs and induced autophagy, respectively. These results provide insights into how L1TD1 regulates gene expression in pluripotent stem cells. We propose that the ability of L1TD1 to dissolve stress granules may provide novel opportunities for treatment of neurodegenerative diseases caused by disturbed stress granule dynamics.
Collapse
Affiliation(s)
- Sang Woo Jin
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul 02841, Republic of Korea
| | - Youngmo Seong
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul 02841, Republic of Korea
| | - Dayoung Yoon
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul 02841, Republic of Korea
| | - Young-Soo Kwon
- Department of Integrative Bioscience & Biotechnology, Sejong University, Seoul 05006, Republic of Korea
| | - Hoseok Song
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul 02841, Republic of Korea
| |
Collapse
|
2
|
Hara T, Meng S, Tsuji Y, Arao Y, Saito Y, Sato H, Motooka D, Uchida S, Ishii H. RN7SL1 may be translated under oncogenic conditions. Proc Natl Acad Sci U S A 2024; 121:e2312322121. [PMID: 38478683 PMCID: PMC10962956 DOI: 10.1073/pnas.2312322121] [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: 07/27/2023] [Accepted: 01/29/2024] [Indexed: 03/27/2024] Open
Abstract
RN7SL1 (RNA component of signal recognition particle 7SL1), a component of the signal recognition particle, is a non-coding RNA possessing a small ORF (smORF). However, whether it is translated into peptides is unknown. Here, we generated the RN7SL1-Green Fluorescent Protein (GFP) gene, in which the smORF of RN7SL1 was replaced by GFP, introduced it into 293T cells, and observed cells emitting GFP fluorescence. Furthermore, RNA-seq of GFP-positive cells revealed that they were in an oncogenic state, suggesting that RN7SL1 smORF may be translated under special conditions.
Collapse
Affiliation(s)
- Tomoaki Hara
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Osaka565-0871, Japan
| | - Sikun Meng
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Osaka565-0871, Japan
| | - Yoshiko Tsuji
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Osaka565-0871, Japan
| | - Yasuko Arao
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Osaka565-0871, Japan
| | - Yoshiko Saito
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Osaka565-0871, Japan
| | - Hiromichi Sato
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Osaka565-0871, Japan
- Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Osaka565-0871, Japan
| | - Daisuke Motooka
- Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka565-0871, Japan
| | - Shizuka Uchida
- Center for RNA Medicine, Department of Clinical Medicine, Aalborg University, Copenhagen SVDK-2450, Denmark
| | - Hideshi Ishii
- Department of Medical Data Science, Center of Medical Innovation and Translational Research, Osaka University Graduate School of Medicine, Suita, Osaka565-0871, Japan
| |
Collapse
|
3
|
Li Y, Shen S, Guo H, Li H, Zhang L, Zhang B, Yu XF, Wei W. Pharmacological inhibition of neddylation impairs long interspersed element 1 retrotransposition. Cell Rep 2024; 43:113749. [PMID: 38329876 DOI: 10.1016/j.celrep.2024.113749] [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: 06/14/2023] [Revised: 09/25/2023] [Accepted: 01/23/2024] [Indexed: 02/10/2024] Open
Abstract
Aberrant long interspersed element 1 (LINE-1 or L1) activity can cause insertional mutagenesis and chromosomal rearrangements and has been detected in several types of cancers. Here, we show that neddylation, a post-translational modification process, is essential for L1 transposition. The antineoplastic drug MLN4924 is an L1 inhibitor that suppresses NEDD8-activating enzyme activity. Neddylation inhibition by MLN4924 selectively impairs ORF2p-mediated L1 reverse transcription and blocks the generation of L1 cDNA. Consistent with these results, MLN4924 treatment suppresses the retrotransposition activity of the non-autonomous retrotransposons short interspersed nuclear element R/variable number of tandem repeat/Alu and Alu, which rely on the reverse transcription activity of L1 ORF2p. The E2 enzyme UBE2M in the neddylation pathway, rather than UBE2F, is required for L1 ORF2p and retrotransposition. Interference with the functions of certain neddylation-dependent Cullin-really interesting new gene E3 ligases disrupts L1 reverse transcription and transposition activity. Our findings provide insights into the regulation of L1 retrotransposition and the identification of therapeutic targets for L1 dysfunctions.
Collapse
Affiliation(s)
- Yan Li
- Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, Institute of Translational Medicine, First Hospital, Jilin University, Changchun, Jilin 130021, China; Department of Pathology, The First Bethune Hospital of Jilin University, Changchun, China
| | - Siyu Shen
- Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, Institute of Translational Medicine, First Hospital, Jilin University, Changchun, Jilin 130021, China
| | - Haoran Guo
- Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, Institute of Translational Medicine, First Hospital, Jilin University, Changchun, Jilin 130021, China
| | - Huili Li
- Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, Institute of Translational Medicine, First Hospital, Jilin University, Changchun, Jilin 130021, China
| | - Lili Zhang
- Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, Institute of Translational Medicine, First Hospital, Jilin University, Changchun, Jilin 130021, China
| | - Boyin Zhang
- Department of Orthopedics Surgery, China-Japan Union Hospital of Jilin University, Changchun 130033, China
| | - Xiao-Fang Yu
- Cancer Institute (Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education), The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310000, China; Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310000, China
| | - Wei Wei
- Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, Institute of Translational Medicine, First Hospital, Jilin University, Changchun, Jilin 130021, China; Institute of Virology and AIDS Research, First Hospital, Jilin University, Changchun, Jilin 130021, China.
| |
Collapse
|
4
|
Li Z, Fang F, Zafar MI, Wu X, Liu X, Tan X, Luo J, Ye Z, Xiong C, Li H. RNA m 6A modification regulates L1 retrotransposons in human spermatogonial stem cell differentiation in vitro and in vivo. Cell Mol Life Sci 2024; 81:92. [PMID: 38363375 PMCID: PMC10873452 DOI: 10.1007/s00018-024-05119-0] [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: 09/26/2023] [Revised: 12/16/2023] [Accepted: 01/07/2024] [Indexed: 02/17/2024]
Abstract
The maintenance of genome integrity in the germline is crucial for mammalian development. Long interspersed element type 1 (LINE-1, L1) is a mobile genetic element that makes up about 17% of the human genome and poses a threat to genome integrity. N6-methyl-adenosine (m6A) plays an essential role in regulating various biological processes. However, the function of m6A modification in L1 retrotransposons and human germline development remains largely unknown. Here we knocked out the m6A methyltransferase METTL3 or the m6A reader YTHDF2 in human embryonic stem cells (hESCs) and discovered that METTL3 and YTHDF2 are crucial for inducing human spermatogonial stem cells (hSSCs) from hESCs in vitro. The removal of METTL3 or YTHDF2 resulted in increased L1 retrotransposition and reduced the efficiency of SSC differentiation in vitro. Further analysis showed that YTHDF2 recognizes the METTL3-catalyzed m6A modification of L1 retrotransposons and degrades L1 mRNA through autophagy, thereby blocking L1 retrotransposition. Moreover, the study confirmed that m6A modification in human fetal germ cells promotes the degradation of L1 retrotransposon RNA, preventing the insertion of new L1 retrotransposons into the genome. Interestingly, L1 retrotransposon RNA was highly expressed while METTL3 was significantly downregulated in the seminal plasma of azoospermic patients with meiotic arrest compared to males with normal fertility. Additionally, we identified some potentially pathogenic variants in m6A-related genes in azoospermic men with meiotic arrest. In summary, our study suggests that m6A modification serves as a guardian of genome stability during human germline development and provides novel insights into the function and regulatory mechanisms of m6A modification in restricting L1 retrotransposition.
Collapse
Affiliation(s)
- Zili Li
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, China
- Wuhan Huake Reproductive Hospital, 128 Sanyang Road, Wuhan, 430013, China
| | - Fang Fang
- Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Mohammad Ishraq Zafar
- Center of Reproductive Medicine, Fourth Affiliated Hospital, Zhejiang University School of Medicine, N1 Shangcheng Avenue, Yiwu, China
| | - Xunwei Wu
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, China
| | - Xinyu Liu
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, China
| | - Xia Tan
- Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Jingwen Luo
- Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Zhen Ye
- Wuhan Huake Reproductive Hospital, 128 Sanyang Road, Wuhan, 430013, China
| | - Chengliang Xiong
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, China.
- Wuhan Huake Reproductive Hospital, 128 Sanyang Road, Wuhan, 430013, China.
- Hubei Engineering Research Center for Preparation, Application and Preservation of Human Stem Cells, Wuhan, 430013, China.
| | - Honggang Li
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, China.
- Wuhan Huake Reproductive Hospital, 128 Sanyang Road, Wuhan, 430013, China.
| |
Collapse
|
5
|
Thawani A, Ariza AJF, Nogales E, Collins K. Template and target-site recognition by human LINE-1 in retrotransposition. Nature 2024; 626:186-193. [PMID: 38096901 PMCID: PMC10830416 DOI: 10.1038/s41586-023-06933-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 12/04/2023] [Indexed: 01/26/2024]
Abstract
The long interspersed element-1 (LINE-1, hereafter L1) retrotransposon has generated nearly one-third of the human genome and serves as an active source of genetic diversity and human disease1. L1 spreads through a mechanism termed target-primed reverse transcription, in which the encoded enzyme (ORF2p) nicks the target DNA to prime reverse transcription of its own or non-self RNAs2. Here we purified full-length L1 ORF2p and biochemically reconstituted robust target-primed reverse transcription with template RNA and target-site DNA. We report cryo-electron microscopy structures of the complete human L1 ORF2p bound to structured template RNAs and initiating cDNA synthesis. The template polyadenosine tract is recognized in a sequence-specific manner by five distinct domains. Among them, an RNA-binding domain bends the template backbone to allow engagement of an RNA hairpin stem with the L1 ORF2p C-terminal segment. Moreover, structure and biochemical reconstitutions demonstrate an unexpected target-site requirement: L1 ORF2p relies on upstream single-stranded DNA to position the adjacent duplex in the endonuclease active site for nicking of the longer DNA strand, with a single nick generating a staggered DNA break. Our research provides insights into the mechanism of ongoing transposition in the human genome and informs the engineering of retrotransposon proteins for gene therapy.
Collapse
Affiliation(s)
- Akanksha Thawani
- California Institute for Quantitative Biosciences (QB3), Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA.
| | - Alfredo Jose Florez Ariza
- California Institute for Quantitative Biosciences (QB3), Berkeley, CA, USA
- Biophysics Graduate Group, University of California Berkeley, Berkeley, CA, USA
| | - Eva Nogales
- California Institute for Quantitative Biosciences (QB3), Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA.
- Howard Hughes Medical Institute, Chevy Chase, MD, USA.
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Kathleen Collins
- California Institute for Quantitative Biosciences (QB3), Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA.
| |
Collapse
|
6
|
Vylegzhanina AV, Bespalov IA, Novototskaya-Vlasova KA, Hall BM, Gleiberman AS, Yu H, Leontieva OV, Leonova KI, Kurnasov OV, Osterman AL, Dy GK, Komissarov AA, Vasilieva E, Gehlhausen J, Iwasaki A, Ambrosone CB, Tsuji T, Matsuzaki J, Odunsi K, Andrianova EL, Gudkov AV. Cancer Relevance of Circulating Antibodies Against LINE-1 Antigens in Humans. CANCER RESEARCH COMMUNICATIONS 2023; 3:2256-2267. [PMID: 37870410 PMCID: PMC10631453 DOI: 10.1158/2767-9764.crc-23-0289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/16/2023] [Accepted: 10/13/2023] [Indexed: 10/24/2023]
Abstract
Long interspersed nuclear element-1 (LINE-1 or L1), the most abundant family of autonomous retrotransposons occupying over 17% of human DNA, is epigenetically silenced in normal tissues by the mechanisms involving p53 but is frequently derepressed in cancer, suggesting that L1-encoded proteins may act as tumor-associated antigens recognized by the immune system. In this study, we established an immunoassay to detect circulating autoantibodies against L1 proteins in human blood. Using this assay in >2,800 individuals with or without cancer, we observed significantly higher IgG titers against L1-encoded ORF1p and ORF2p in patients with lung, pancreatic, ovarian, esophageal, and liver cancers than in healthy individuals. Remarkably, elevated levels of anti-ORF1p-reactive IgG were observed in patients with cancer with disease stages 1 and 2, indicating that the immune response to L1 antigens can occur in the early phases of carcinogenesis. We concluded that the antibody response against L1 antigens could contribute to the diagnosis and determination of immunoreactivity of tumors among cancer types that frequently escape early detection. SIGNIFICANCE The discovery of autoantibodies against antigens encoded by L1 retrotransposons in patients with five poorly curable cancer types has potential implications for the detection of an ongoing carcinogenic process and tumor immunoreactivity.
Collapse
Affiliation(s)
| | | | | | | | | | - Han Yu
- Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | | | | | - Oleg V. Kurnasov
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Andrei L. Osterman
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Grace K. Dy
- Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Alexey A. Komissarov
- I.V. Davydovsky Clinical City Hospital, Moscow, Russia
- A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow, Russia
| | - Elena Vasilieva
- I.V. Davydovsky Clinical City Hospital, Moscow, Russia
- A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow, Russia
| | | | - Akiko Iwasaki
- Yale University, New Haven, Connecticut
- Howard Hughes Medical Institute, Chevy Chase, Maryland
| | | | - Takemasa Tsuji
- University of Chicago Medicine Comprehensive Cancer Center, Chicago, Illinois
| | - Junko Matsuzaki
- University of Chicago Medicine Comprehensive Cancer Center, Chicago, Illinois
| | - Kunle Odunsi
- University of Chicago Medicine Comprehensive Cancer Center, Chicago, Illinois
| | | | - Andrei V. Gudkov
- Genome Protection, Inc., Buffalo, New York
- Roswell Park Comprehensive Cancer Center, Buffalo, New York
| |
Collapse
|
7
|
Du Q, Stow EC, LaCoste D, Freeman B, Baddoo M, Shareef A, Miller KM, Belancio VP. A novel role of TRIM28 B box domain in L1 retrotransposition and ORF2p-mediated cDNA synthesis. Nucleic Acids Res 2023; 51:4429-4450. [PMID: 37070200 PMCID: PMC10201437 DOI: 10.1093/nar/gkad247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 03/22/2023] [Accepted: 03/25/2023] [Indexed: 04/19/2023] Open
Abstract
The long interspersed element 1 (LINE-1 or L1) integration is affected by many cellular factors through various mechanisms. Some of these factors are required for L1 amplification, while others either suppress or enhance specific steps during L1 propagation. Previously, TRIM28 has been identified to suppress transposable elements, including L1 expression via its canonical role in chromatin remodeling. Here, we report that TRIM28 through its B box domain increases L1 retrotransposition and facilitates shorter cDNA and L1 insert generation in cultured cells. Consistent with the latter, we observe that tumor specific L1 inserts are shorter in endometrial, ovarian, and prostate tumors with higher TRIM28 mRNA expression than in those with lower TRIM28 expression. We determine that three amino acids in the B box domain that are involved in TRIM28 multimerization are critical for its effect on both L1 retrotransposition and cDNA synthesis. We provide evidence that B boxes from the other two members in the Class VI TRIM proteins, TRIM24 and TRIM33, also increase L1 retrotransposition. Our findings could lead to a better understanding of the host/L1 evolutionary arms race in the germline and their interplay during tumorigenesis.
Collapse
Affiliation(s)
- Qianhui Du
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans 70112, USA
| | - Emily C Stow
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans 70112, USA
| | - Dawn LaCoste
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans 70112, USA
| | - Benjamin Freeman
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans 70112, USA
| | - Melody Baddoo
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
| | - Afzaal M Shareef
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans 70112, USA
| | - Kyle M Miller
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, University of Texas at Austin, 100 E 24th Street, Austin, TX 78712, USA
| | - Victoria P Belancio
- Tulane Cancer Center, Tulane Health Sciences Center, 1700 Tulane Ave, New Orleans, LA 70112, USA
- Department of Structural and Cellular Biology, Tulane School of Medicine, 1430 Tulane Ave, New Orleans 70112, USA
| |
Collapse
|
8
|
Warkocki Z. An update on post-transcriptional regulation of retrotransposons. FEBS Lett 2023; 597:380-406. [PMID: 36460901 DOI: 10.1002/1873-3468.14551] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 11/09/2022] [Accepted: 11/18/2022] [Indexed: 12/04/2022]
Abstract
Retrotransposons, including LINE-1, Alu, SVA, and endogenous retroviruses, are one of the major constituents of human genomic repetitive sequences. Through the process of retrotransposition, some of them occasionally insert into new genomic locations by a copy-paste mechanism involving RNA intermediates. Irrespective of de novo genomic insertions, retrotransposon expression can lead to DNA double-strand breaks and stimulate cellular innate immunity through endogenous patterns. As a result, retrotransposons are tightly regulated by multi-layered regulatory processes to prevent the dangerous effects of their expression. In recent years, significant progress was made in revealing how retrotransposon biology intertwines with general post-transcriptional RNA metabolism. Here, I summarize current knowledge on the involvement of post-transcriptional factors in the biology of retrotransposons, focusing on LINE-1. I emphasize general RNA metabolisms such as methylation of adenine (m6 A), RNA 3'-end polyadenylation and uridylation, RNA decay and translation regulation. I discuss the effects of retrotransposon RNP sequestration in cytoplasmic bodies and autophagy. Finally, I summarize how innate immunity restricts retrotransposons and how retrotransposons make use of cellular enzymes, including the DNA repair machinery, to complete their replication cycles.
Collapse
Affiliation(s)
- Zbigniew Warkocki
- Department of RNA Metabolism, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| |
Collapse
|
9
|
Lee H, Min JW, Mun S, Han K. Human Retrotransposons and Effective Computational Detection Methods for Next-Generation Sequencing Data. LIFE (BASEL, SWITZERLAND) 2022; 12:life12101583. [PMID: 36295018 PMCID: PMC9605557 DOI: 10.3390/life12101583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/03/2022] [Accepted: 10/10/2022] [Indexed: 11/16/2022]
Abstract
Transposable elements (TEs) are classified into two classes according to their mobilization mechanism. Compared to DNA transposons that move by the "cut and paste" mechanism, retrotransposons mobilize via the "copy and paste" method. They have been an essential research topic because some of the active elements, such as Long interspersed element 1 (LINE-1), Alu, and SVA elements, have contributed to the genetic diversity of primates beyond humans. In addition, they can cause genetic disorders by altering gene expression and generating structural variations (SVs). The development and rapid technological advances in next-generation sequencing (NGS) have led to new perspectives on detecting retrotransposon-mediated SVs, especially insertions. Moreover, various computational methods have been developed based on NGS data to precisely detect the insertions and deletions in the human genome. Therefore, this review discusses details about the recently studied and utilized NGS technologies and the effective computational approaches for discovering retrotransposons through it. The final part covers a diverse range of computational methods for detecting retrotransposon insertions with human NGS data. This review will give researchers insights into understanding the TEs and how to investigate them and find connections with research interests.
Collapse
Affiliation(s)
- Haeun Lee
- Department of Bioconvergence Engineering, Dankook University, Yongin 16890, Korea
| | - Jun Won Min
- Department of Surgery, Dankook University College of Medicine, Cheonan 31116, Korea
| | - Seyoung Mun
- Department of Microbiology, College of Science & Technology, Dankook University, Cheonan 31116, Korea
- Center for Bio Medical Engineering Core Facility, Dankook University, Cheonan 31116, Korea
- Correspondence: (S.M.); (K.H.)
| | - Kyudong Han
- Department of Bioconvergence Engineering, Dankook University, Yongin 16890, Korea
- Department of Microbiology, College of Science & Technology, Dankook University, Cheonan 31116, Korea
- Center for Bio Medical Engineering Core Facility, Dankook University, Cheonan 31116, Korea
- HuNbiome Co., Ltd., R&D Center, Seoul 08507, Korea
- Correspondence: (S.M.); (K.H.)
| |
Collapse
|
10
|
RNA m 6A modification orchestrates a LINE-1-host interaction that facilitates retrotransposition and contributes to long gene vulnerability. Cell Res 2021; 31:861-885. [PMID: 34108665 PMCID: PMC8324889 DOI: 10.1038/s41422-021-00515-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 04/27/2021] [Indexed: 02/06/2023] Open
Abstract
The molecular basis underlying the interaction between retrotransposable elements (RTEs) and the human genome remains poorly understood. Here, we profiled N6-methyladenosine (m6A) deposition on nascent RNAs in human cells by developing a new method MINT-Seq, which revealed that many classes of RTE RNAs, particularly intronic LINE-1s (L1s), are strongly methylated. These m6A-marked intronic L1s (MILs) are evolutionarily young, sense-oriented to hosting genes, and are bound by a dozen RNA binding proteins (RBPs) that are putative novel readers of m6A-modified RNAs, including a nuclear matrix protein SAFB. Notably, m6A positively controls the expression of both autonomous L1s and co-transcribed L1 relics, promoting L1 retrotransposition. We showed that MILs preferentially reside in long genes with critical roles in DNA damage repair and sometimes in L1 suppression per se, where they act as transcriptional "roadblocks" to impede the hosting gene expression, revealing a novel host-weakening strategy by the L1s. In counteraction, the host uses the SAFB reader complex to bind m6A-L1s to reduce their levels, and to safeguard hosting gene transcription. Remarkably, our analysis identified thousands of MILs in multiple human fetal tissues, enlisting them as a novel category of cell-type-specific regulatory elements that often compromise transcription of long genes and confer their vulnerability in neurodevelopmental disorders. We propose that this m6A-orchestrated L1-host interaction plays widespread roles in gene regulation, genome integrity, human development and diseases.
Collapse
|
11
|
Alkailani M, Palidwor G, Poulin A, Mohan R, Pepin D, Vanderhyden B, Gibbings D. A genome-wide strategy to identify causes and consequences of retrotransposon expression finds activation by BRCA1 in ovarian cancer. NAR Cancer 2021; 3:zcaa040. [PMID: 33447827 PMCID: PMC7787265 DOI: 10.1093/narcan/zcaa040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 11/20/2020] [Accepted: 11/30/2020] [Indexed: 12/03/2022] Open
Abstract
It is challenging to identify the causes and consequences of retrotransposon expression in human disease due to the hundreds of active genomic copies and their poor conservation across species. We profiled genomic insertions of retrotransposons in ovarian cancer. In addition, in ovarian and breast cancer we analyzed RNAs exhibiting Bayesian correlation with retrotransposon RNA to identify causes and consequences of retrotransposon expression. This strategy finds divergent inflammatory responses associated with retrotransposon expression in ovarian and breast cancer and identifies new factors inducing expression of endogenous retrotransposons including anti-viral responses and the common tumor suppressor BRCA1. In cell lines, mouse ovarian epithelial cells and patient-derived tumor spheroids, BRCA1 promotes accumulation of retrotransposon RNA. BRCA1 promotes transcription of active families of retrotransposons and their insertion into the genome. Intriguingly, elevated retrotransposon expression predicts survival in ovarian cancer patients. Retrotransposons are part of a complex regulatory network in ovarian cancer including BRCA1 that contributes to patient survival. The described strategy can be used to identify the regulators and impacts of retrotransposons in various contexts of biology and disease in humans.
Collapse
Affiliation(s)
- Maisa Alkailani
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
| | - Gareth Palidwor
- Ottawa Institute for Systems Biology, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
- Bioinformatics, Ottawa Hospital Research Institute, Ottawa, Ontario, K1H 8L6, Canada
| | - Ariane Poulin
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
| | - Raghav Mohan
- Pediatrics Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA 021145, USA
| | - David Pepin
- Pediatrics Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA 021145, USA
- Department of Surgery, Harvard Medical School, Boston, MA 021156, USA
| | - Barbara Vanderhyden
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Ontario, K1H 8L6, Canada
| | - Derrick Gibbings
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada
| |
Collapse
|
12
|
Gallop Racing Shifts Mature mRNA towards Introns: Does Exercise-Induced Stress Enhance Genome Plasticity? Genes (Basel) 2020; 11:genes11040410. [PMID: 32283859 PMCID: PMC7230505 DOI: 10.3390/genes11040410] [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: 02/28/2020] [Revised: 03/26/2020] [Accepted: 04/07/2020] [Indexed: 12/25/2022] Open
Abstract
Physical exercise is universally recognized as stressful. Among the "sport species", the horse is probably the most appropriate model for investigating the genomic response to stress due to the homogeneity of its genetic background. The aim of this work is to dissect the whole transcription modulation in Peripheral Blood Mononuclear Cells (PBMCs) after exercise with a time course framework focusing on unexplored regions related to introns and intergenic portions. PBMCs NGS from five 3 year old Sardinian Anglo-Arab racehorses collected at rest and after a 2000 m race was performed. Apart from differential gene expression ascertainment between the two time points the complexity of transcription for alternative transcripts was identified. Interestingly, we noted a transcription shift from the coding to the non-coding regions. We further investigated the possible causes of this phenomenon focusing on genomic repeats, using a differential expression approach and finding a strong general up-regulation of repetitive elements such as LINE. Since their modulation is also associated with the "exonization", the recruitment of repeats that act with regulatory functions, suggesting that there might be an active regulation of this transcriptional shift. Thanks to an innovative bioinformatic approach, our study could represent a model for the transcriptomic investigation of stress.
Collapse
|
13
|
Choi J, Hwang SY, Ahn K. Interplay between RNASEH2 and MOV10 controls LINE-1 retrotransposition. Nucleic Acids Res 2019; 46:1912-1926. [PMID: 29315404 PMCID: PMC5829647 DOI: 10.1093/nar/gkx1312] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 12/23/2017] [Indexed: 01/22/2023] Open
Abstract
Long interspersed nuclear element 1 is an autonomous non-long terminal repeat retrotransposon that comprises ∼17% of the human genome. Its spontaneous retrotransposition and the accumulation of heritable L1 insertions can potentially result in genome instability and sporadic disorders. Moloney leukemia virus 10 homolog (MOV10), a putative RNA helicase, has been implicated in inhibiting L1 replication, although its underlying mechanism of action remains obscure. Moreover, the physiological relevance of MOV10-mediated L1 regulation in human disease has not yet been examined. Using a proteomic approach, we identified RNASEH2 as a binding partner of MOV10. We show that MOV10 interacts with RNASEH2, and their interplay is crucial for restricting L1 retrotransposition. RNASEH2 and MOV10 co-localize in the nucleus, and RNASEH2 binds to L1 RNAs in a MOV10-dependent manner. Small hairpin RNA-mediated depletion of either RNASEH2A or MOV10 results in an accumulation of L1-specific RNA-DNA hybrids, suggesting they contribute to prevent formation of vital L1 heteroduplexes during retrotransposition. Furthermore, we show that RNASEH2-MOV10-mediated L1 restriction downregulates expression of the rheumatoid arthritis-associated inflammatory cytokines and matrix-degrading proteinases in synovial cells, implicating a potential causal relationship between them and disease development in terms of disease predisposition.
Collapse
Affiliation(s)
- Jongsu Choi
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Republic of Korea.,School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Sung-Yeon Hwang
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Republic of Korea.,School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Kwangseog Ahn
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Republic of Korea.,School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea
| |
Collapse
|
14
|
Gagnier L, Belancio VP, Mager DL. Mouse germ line mutations due to retrotransposon insertions. Mob DNA 2019; 10:15. [PMID: 31011371 PMCID: PMC6466679 DOI: 10.1186/s13100-019-0157-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/01/2019] [Indexed: 12/24/2022] Open
Abstract
Transposable element (TE) insertions are responsible for a significant fraction of spontaneous germ line mutations reported in inbred mouse strains. This major contribution of TEs to the mutational landscape in mouse contrasts with the situation in human, where their relative contribution as germ line insertional mutagens is much lower. In this focussed review, we provide comprehensive lists of TE-induced mouse mutations, discuss the different TE types involved in these insertional mutations and elaborate on particularly interesting cases. We also discuss differences and similarities between the mutational role of TEs in mice and humans.
Collapse
Affiliation(s)
- Liane Gagnier
- Terry Fox Laboratory, BC Cancer and Department of Medical Genetics, University of British Columbia, V5Z1L3, Vancouver, BC Canada
| | - Victoria P. Belancio
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112 USA
| | - Dixie L. Mager
- Terry Fox Laboratory, BC Cancer and Department of Medical Genetics, University of British Columbia, V5Z1L3, Vancouver, BC Canada
| |
Collapse
|
15
|
Wagstaff BJ, Wang L, Lai S, Derbes RS, Roy-Engel AM. Reviving a 60 million year old LINE-1 element. GENE REPORTS 2018; 11:74-78. [PMID: 30221208 DOI: 10.1016/j.genrep.2018.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Mobile elements have significantly impacted genome structure of most organisms. The continued activity of the mobile element, LINE-1 (L1), through time has contributed to the accumulation of over half a million L1 copies in the human genome. Most copies in the human genome belong to evolutionary older extinct L1s. Here we apply our previous published approach to "revive" the extinct L1 PA13A; an L1 family that was active about 60 million year ago (mya). The reconstructed L1PA13A is retrocompentent in culture, but shows a significantly lower level of activity in HeLa cells when compared to the modern L1 element (L1PA1) and a 40 million year old L1PA8. L1 elements code for two proteins (ORF1p and ORF2p) that are necessary for retrotransposition. Using PA13A-PA1 and PA13A-PA8 L1 chimeric elements, we determined that both the ORF1p and ORF2p contribute to the observed decrease in retrotransposition efficiency of L1PA13A. The lower retrotransposition rate of L1PA13A is consistent in both human and rodent cell lines. However, in rodent cells, the chimeric element L1PA:1-13 containing the modern L1PA1 ORF1p shows a recovery in the retrotransposition rate, suggestive that the L1PA13A ORF2p efficiently drives retrotransposition in these cells. The functionality of the L1PA13A ORF2p was further confirmed by demonstrating its ability to drive Alu retrotransposition in rodent cells. The variation in L1PA13A retrotransposition rates observed between rodent and human cells are suggestive that cellular environment significantly affects retrotransposition efficiency, which may be mediated through an interaction with ORF1p. Based on these observations, we speculate that the observed differences between cell lines may reflect an evolutionary adaptation of the L1 element to its host cell.
Collapse
Affiliation(s)
- Bradley J Wagstaff
- Tulane Cancer Center SL-66, Dept. of Epidemiology, Tulane University Health Sciences Center, 1430 Tulane Ave., New Orleans, LA 70112
| | - Linda Wang
- Tulane Cancer Center SL-66, Dept. of Epidemiology, Tulane University Health Sciences Center, 1430 Tulane Ave., New Orleans, LA 70112
| | - Susan Lai
- Tulane Cancer Center SL-66, Dept. of Epidemiology, Tulane University Health Sciences Center, 1430 Tulane Ave., New Orleans, LA 70112
| | - Rebecca S Derbes
- Tulane Cancer Center SL-66, Dept. of Epidemiology, Tulane University Health Sciences Center, 1430 Tulane Ave., New Orleans, LA 70112
| | - Astrid M Roy-Engel
- Tulane Cancer Center SL-66, Dept. of Epidemiology, Tulane University Health Sciences Center, 1430 Tulane Ave., New Orleans, LA 70112
| |
Collapse
|
16
|
Sahebi M, Hanafi MM, van Wijnen AJ, Rice D, Rafii MY, Azizi P, Osman M, Taheri S, Bakar MFA, Isa MNM, Noor YM. Contribution of transposable elements in the plant's genome. Gene 2018; 665:155-166. [PMID: 29684486 DOI: 10.1016/j.gene.2018.04.050] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/04/2018] [Accepted: 04/18/2018] [Indexed: 12/26/2022]
Abstract
Plants maintain extensive growth flexibility under different environmental conditions, allowing them to continuously and rapidly adapt to alterations in their environment. A large portion of many plant genomes consists of transposable elements (TEs) that create new genetic variations within plant species. Different types of mutations may be created by TEs in plants. Many TEs can avoid the host's defense mechanisms and survive alterations in transposition activity, internal sequence and target site. Thus, plant genomes are expected to utilize a variety of mechanisms to tolerate TEs that are near or within genes. TEs affect the expression of not only nearby genes but also unlinked inserted genes. TEs can create new promoters, leading to novel expression patterns or alternative coding regions to generate alternate transcripts in plant species. TEs can also provide novel cis-acting regulatory elements that act as enhancers or inserts within original enhancers that are required for transcription. Thus, the regulation of plant gene expression is strongly managed by the insertion of TEs into nearby genes. TEs can also lead to chromatin modifications and thereby affect gene expression in plants. TEs are able to generate new genes and modify existing gene structures by duplicating, mobilizing and recombining gene fragments. They can also facilitate cellular functions by sharing their transposase-coding regions. Hence, TE insertions can not only act as simple mutagens but can also alter the elementary functions of the plant genome. Here, we review recent discoveries concerning the contribution of TEs to gene expression in plant genomes and discuss the different mechanisms by which TEs can affect plant gene expression and reduce host defense mechanisms.
Collapse
Affiliation(s)
- Mahbod Sahebi
- Laboratory of Climate-Smart Food Crop Production, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | - Mohamed M Hanafi
- Laboratory of Climate-Smart Food Crop Production, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; Laboratory of Plantation Science and Technology, Institute of Plantation Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; Department of Land Management, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | | | - David Rice
- Department of Molecular Biology & Biotecnology, University of Sheffield, United Kingdom
| | - M Y Rafii
- Laboratory of Climate-Smart Food Crop Production, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Parisa Azizi
- Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Mohamad Osman
- Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Sima Taheri
- Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | | | | | | |
Collapse
|
17
|
Ade CM, Derbes RS, Wagstaff BJ, Linker SB, White TB, Deharo D, Belancio VP, Ivics Z, Roy-Engel AM. Evaluating different DNA binding domains to modulate L1 ORF2p-driven site-specific retrotransposition events in human cells. Gene 2017; 642:188-198. [PMID: 29154869 DOI: 10.1016/j.gene.2017.11.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 11/11/2017] [Indexed: 12/28/2022]
Abstract
DNA binding domains (DBDs) have been used with great success to impart targeting capabilities to a variety of proteins creating highly useful genomic tools. We evaluated the ability of five types of DBDs and strategies (AAV Rep proteins, Cre, TAL effectors, zinc finger proteins, and Cas9/gRNA system) to target the L1 ORF2 protein to drive retrotransposition of Alu inserts to specific sequences in the human genome. First, we find that the L1 ORF2 protein tolerates the addition of protein domains both at the amino- and carboxy-terminus. Although in some instances retrotransposition efficiencies slightly diminished, all fusion proteins containing an intact ORF2 were capable of driving retrotransposition. Second, the stability of individual ORF2 fusion proteins varies and difficult to predict. Third, DBDs that require the formation of multimers for target recognition are unlikely to modify targeting of ORF2p-driven insertions. Fourth, the more components needed to assemble into a complex to drive targeted retrotransposition, the less likely the strategy will increase targeted insertions. Fifth, abundance of target sequences present in the genome will likely dictate the effectiveness and efficiency of targeted insertions. Lastly, the cleavage capabilities of Cas9 (or a Cas9 nickase variant) are unable to substitute for the L1 ORF2 endonuclease domain functions, suggestive that the endonuclease domain has alternate functions needed for retrotransposition. From these studies, we conclude that the most critical component for the modification of the human L1 ORF2 protein to drive targeted insertions is the selection of the DBD due to the varying functional requirements and impacts on protein stability.
Collapse
Affiliation(s)
- Catherine M Ade
- Department of Cellular and Molecular Biology, Tulane University, USA
| | - Rebecca S Derbes
- Tulane Cancer Center SL-66, Dept. of Epidemiology, Tulane University Health Sciences Center and LCRC, 1700 Tulane Ave., New Orleans, LA 70112, USA
| | - Bradley J Wagstaff
- Tulane Cancer Center SL-66, Dept. of Epidemiology, Tulane University Health Sciences Center and LCRC, 1700 Tulane Ave., New Orleans, LA 70112, USA
| | - Sara B Linker
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 N Torrey Pines Road, La Jolla, CA 92037-1002, USA
| | - Travis B White
- Sloan Kettering Institute for Cancer Research, New York, NY 10065, USA
| | - Dawn Deharo
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112, USA
| | - Victoria P Belancio
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112, USA
| | - Zoltán Ivics
- Division of Medical Biotechnology, Paul-Ehrlich-Institute, Langen, Germany
| | - Astrid M Roy-Engel
- Tulane Cancer Center SL-66, Dept. of Epidemiology, Tulane University Health Sciences Center and LCRC, 1700 Tulane Ave., New Orleans, LA 70112, USA.
| |
Collapse
|
18
|
Nakajima R, Sato T, Ogawa T, Okano H, Noce T. A noncoding RNA containing a SINE-B1 motif associates with meiotic metaphase chromatin and has an indispensable function during spermatogenesis. PLoS One 2017; 12:e0179585. [PMID: 28658256 PMCID: PMC5489172 DOI: 10.1371/journal.pone.0179585] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 06/01/2017] [Indexed: 12/24/2022] Open
Abstract
A search for early response genes that are activated following germ cell induction from mouse embryonic stem cells in vitro led us to the isolation of a long noncoding RNA that contains a SINE (short interspersed element)-B1F motif that was named R53. In situ hybridization and northern blot analyses revealed that the R53 subfragment RNA bears a B1F motif, is processed from the primary transcript, is expressed in adult testis and is predominantly localized in meiotic metaphase chromatin during spermatogenesis. Recent studies of chromosome-associated RNAs have explored novel functions of noncoding RNAs. Specifically, chromosome-bound noncoding RNAs function not only as structural components of chromosome but also as scaffolds that recruit epigenetic modulators for transcriptional regulation, and they are dynamically rearranged during the cell cycle. However, few studies have explored meiotic chromatin; thus, R53 RNA appears to be the first long noncoding RNA to be tightly associated with the metaphase chromatin during spermatogenesis. Furthermore, R53 knockdown using a lentivirus-mediated RNAi injected into mouse testis and organ culture of the fragments revealed a remarkable reduction in postmeiotic cells and irregular up-regulation of several postmeiotic genes, which suggests the possibility that the SINE-B1-derived noncoding RNA R53 plays an indispensable role in the transcriptional regulation of key spermatogenesis genes.
Collapse
Affiliation(s)
- Ryusuke Nakajima
- Department of Physiology, Keio University School of Medicine, 35 Shinamomachi, Shinjuku-ku, Tokyo, Japan
- * E-mail: (RN); (TN)
| | - Takuya Sato
- Laboratory of Proteomics, Institute of Molecular Medicine and Life Science, Yokohama City University Association of Medical Science, Yokohama, Kanagawa, Japan
| | - Takehiko Ogawa
- Laboratory of Proteomics, Institute of Molecular Medicine and Life Science, Yokohama City University Association of Medical Science, Yokohama, Kanagawa, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, 35 Shinamomachi, Shinjuku-ku, Tokyo, Japan
| | - Toshiaki Noce
- Department of Physiology, Keio University School of Medicine, 35 Shinamomachi, Shinjuku-ku, Tokyo, Japan
- * E-mail: (RN); (TN)
| |
Collapse
|
19
|
Pugacheva EM, Teplyakov E, Wu Q, Li J, Chen C, Meng C, Liu J, Robinson S, Loukinov D, Boukaba A, Hutchins AP, Lobanenkov V, Strunnikov A. The cancer-associated CTCFL/BORIS protein targets multiple classes of genomic repeats, with a distinct binding and functional preference for humanoid-specific SVA transposable elements. Epigenetics Chromatin 2016; 9:35. [PMID: 27588042 PMCID: PMC5007689 DOI: 10.1186/s13072-016-0084-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/18/2016] [Indexed: 12/20/2022] Open
Abstract
Background A common aberration in cancer is the activation of germline-specific proteins. The DNA-binding proteins among them could generate novel chromatin states, not found in normal cells. The germline-specific transcription factor BORIS/CTCFL, a paralog of chromatin architecture protein CTCF, is often erroneously activated in cancers and rewires the epigenome for the germline-like transcription program. Another common feature of malignancies is the changed expression and epigenetic states of genomic repeats, which could alter the transcription of neighboring genes and cause somatic mutations upon transposition. The role of BORIS in transposable elements and other repeats has never been assessed. Results The investigation of BORIS and CTCF binding to DNA repeats in the K562 cancer cells dependent on BORIS for self-renewal by ChIP-chip and ChIP-seq revealed three classes of occupancy by these proteins: elements cohabited by BORIS and CTCF, CTCF-only bound, or BORIS-only bound. The CTCF-only enrichment is characteristic for evolutionary old and inactive repeat classes, while BORIS and CTCF co-binding predominately occurs at uncharacterized tandem repeats. These repeats form staggered cluster binding sites, which are a prerequisite for CTCF and BORIS co-binding. At the same time, BORIS preferentially occupies a specific subset of the evolutionary young, transcribed, and mobile genomic repeat family, SVA. Unlike CTCF, BORIS prominently binds to the VNTR region of the SVA repeats in vivo. This suggests a role of BORIS in SVA expression regulation. RNA-seq analysis indicates that BORIS largely serves as a repressor of SVA expression, alongside DNA and histone methylation, with the exception of promoter capture by SVA. Conclusions Thus, BORIS directly binds to, and regulates SVA repeats, which are essentially movable CpG islands, via clusters of BORIS binding sites. This finding uncovers a new function of the global germline-specific transcriptional regulator BORIS in regulating and repressing the newest class of transposable elements that are actively transposed in human genome when activated. This function of BORIS in cancer cells is likely a reflection of its roles in the germline. Electronic supplementary material The online version of this article (doi:10.1186/s13072-016-0084-2) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
| | - Evgeny Teplyakov
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Qiongfang Wu
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Jingjing Li
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Cheng Chen
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Chengcheng Meng
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Jian Liu
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Susan Robinson
- Laboratory of Immunogenetics, NIH, NIAID, Rockville, MD 20852 USA
| | - Dmitry Loukinov
- Laboratory of Immunogenetics, NIH, NIAID, Rockville, MD 20852 USA
| | - Abdelhalim Boukaba
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| | - Andrew Paul Hutchins
- Department of Biology, Southern University of Science and Technology of China, Shenzhen, 518055 Guangdong China
| | | | - Alexander Strunnikov
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, 510530 Guangdong China
| |
Collapse
|
20
|
Abstract
Transposable elements (TEs) are both a boon and a bane to eukaryotic organisms, depending on where they integrate into the genome and how their sequences function once integrated. We focus on two types of TEs: long interspersed elements (LINEs) and short interspersed elements (SINEs). LINEs and SINEs are retrotransposons; that is, they transpose via an RNA intermediate. We discuss how LINEs and SINEs have expanded in eukaryotic genomes and contribute to genome evolution. An emerging body of evidence indicates that LINEs and SINEs function to regulate gene expression by affecting chromatin structure, gene transcription, pre-mRNA processing, or aspects of mRNA metabolism. We also describe how adenosine-to-inosine editing influences SINE function and how ongoing retrotransposition is countered by the body's defense mechanisms.
Collapse
Affiliation(s)
- Reyad A Elbarbary
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA. Center for RNA Biology, University of Rochester, Rochester, NY, USA
| | - Bronwyn A Lucas
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA. Center for RNA Biology, University of Rochester, Rochester, NY, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA. Center for RNA Biology, University of Rochester, Rochester, NY, USA. Department of Oncology, Wilmot Cancer Institute, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.
| |
Collapse
|
21
|
Abstract
Repetitive genetic elements have had an unprecedented success populating phylogenetically diverse species making them a common feature of most genomes. Hundreds of thousands of copies of active and non-functional transposable elements representing different classes and families can reside within and outside of host genes. In addition to creating structural variations in genomic DNA, some of these loci are expressed to contribute to the continuing amplification cycle. Transposable elements, specifically Long Interspersed Element-1 (LINE-1) produce a spectrum of RNAs, some of which are important for their mobilization, while others are processed forms of LINE-1 transcription that may or may not play relevant functions. Additionally, many LINE-1 sequences integrated into cellular genes are included into cellular transcripts creating substantial background when L1-related RNA expression is detected by some conventional methods. This chapter provides an in-depth description of the complexity of L1-generated mRNAs as well as sources of cellular transcripts containing L1 sequences. It also highlights the strengths and weaknesses of conventional methods used to detect LINE-1 expression.
Collapse
Affiliation(s)
- Prescott Deininger
- Department of Epidemiology, Tulane School of Public Health, New Orleans, LA, USA
- Tulane Cancer Center and Center for Aging, New Orleans, LA, USA
| | - Victoria P Belancio
- Tulane Cancer Center and Center for Aging, New Orleans, LA, USA.
- Department of Structural and Cellular biology, Tulane School of Medicine, SL49, 1430 Tulane Ave., New Orleans, LA, 70112, USA.
| |
Collapse
|
22
|
Ade C, Roy-Engel AM. SINE Retrotransposition: Evaluation of Alu Activity and Recovery of De Novo Inserts. Methods Mol Biol 2016; 1400:183-201. [PMID: 26895055 DOI: 10.1007/978-1-4939-3372-3_13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Mobile element activity is of great interest due to its impact on genomes. However, the types of mobile elements that inhabit any given genome are remarkably varied. Among the different varieties of mobile elements, the Short Interspersed Elements (SINEs) populate many genomes, including many mammalian species. Although SINEs are parasites of Long Interspersed Elements (LINEs), SINEs have been highly successful in both the primate and rodent genomes. When comparing copy numbers in mammals, SINEs have been vastly more successful than other nonautonomous elements, such as the retropseudogenes and SVA. Interestingly, in the human genome the copy number of Alu (a primate SINE) outnumbers LINE-1 (L1) copies 2 to 1. Estimates suggest that the retrotransposition rate for Alu is tenfold higher than LINE-1 with about 1 insert in every twenty births. Furthermore, Alu-induced mutagenesis is responsible for the majority of the documented instances of human retroelement insertion-induced disease. However, little is known on what contributes to these observed differences between SINEs and LINEs. The development of an assay to monitor SINE retrotransposition in culture has become an important tool for the elucidation of some of these differences. In this chapter, we present details of the SINE retrotransposition assay and the recovery of de novo inserts. We also focus on the nuances that are unique to the SINE assay.
Collapse
Affiliation(s)
- Catherine Ade
- Department of Epidemiology, Tulane Cancer Center, SL-66, Tulane University Health Sciences Center, 1430 Tulane Ave., New Orleans, LA, 70112, USA
| | - Astrid M Roy-Engel
- Department of Epidemiology, Tulane Cancer Center, SL-66, Tulane University Health Sciences Center, 1430 Tulane Ave., New Orleans, LA, 70112, USA.
| |
Collapse
|
23
|
Naufer MN, Callahan KE, Cook PR, Perez-Gonzalez CE, Williams MC, Furano AV. L1 retrotransposition requires rapid ORF1p oligomerization, a novel coiled coil-dependent property conserved despite extensive remodeling. Nucleic Acids Res 2015; 44:281-93. [PMID: 26673717 PMCID: PMC4705668 DOI: 10.1093/nar/gkv1342] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 11/17/2015] [Indexed: 12/16/2022] Open
Abstract
Detailed mechanistic understanding of L1 retrotransposition is sparse, particularly with respect to ORF1p, a coiled coil-mediated homotrimeric nucleic acid chaperone that can form tightly packed oligomers on nucleic acids. Although the coiled coil motif is highly conserved, it is uniquely susceptible to evolutionary change. Here we studied three ORF1 proteins: a modern human one (111p), its resuscitated primate ancestor (555p) and a mosaic modern protein (151p) wherein 9 of the 30 coiled coil substitutions retain their ancestral state. While 111p and 555p equally supported retrotransposition, 151p was inactive. Nonetheless, they were fully active in bulk assays of nucleic acid interactions including chaperone activity. However, single molecule assays showed that 151p trimers form stably bound oligomers on ssDNA at <1/10th the rate of the active proteins, revealing that oligomerization rate is a novel critical parameter of ORF1p activity in retrotransposition conserved for at least the last 25 Myr of primate evolution.
Collapse
Affiliation(s)
- M Nabuan Naufer
- Northeastern University, Department of Physics, Boston, MA 02115, USA
| | - Kathryn E Callahan
- Laboratory of Cellular and Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Pamela R Cook
- Laboratory of Cellular and Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Cesar E Perez-Gonzalez
- Laboratory of Cellular and Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mark C Williams
- Northeastern University, Department of Physics, Boston, MA 02115, USA
| | - Anthony V Furano
- Laboratory of Cellular and Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| |
Collapse
|
24
|
Conti A, Carnevali D, Bollati V, Fustinoni S, Pellegrini M, Dieci G. Identification of RNA polymerase III-transcribed Alu loci by computational screening of RNA-Seq data. Nucleic Acids Res 2014; 43:817-35. [PMID: 25550429 PMCID: PMC4333407 DOI: 10.1093/nar/gku1361] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Of the ∼1.3 million Alu elements in the human genome, only a tiny number are estimated to be active in transcription by RNA polymerase (Pol) III. Tracing the individual loci from which Alu transcripts originate is complicated by their highly repetitive nature. By exploiting RNA-Seq data sets and unique Alu DNA sequences, we devised a bioinformatic pipeline allowing us to identify Pol III-dependent transcripts of individual Alu elements. When applied to ENCODE transcriptomes of seven human cell lines, this search strategy identified ∼1300 Alu loci corresponding to detectable transcripts, with ∼120 of them expressed in at least three cell lines. In vitro transcription of selected Alus did not reflect their in vivo expression properties, and required the native 5′-flanking region in addition to internal promoter. We also identified a cluster of expressed AluYa5-derived transcription units, juxtaposed to snaR genes on chromosome 19, formed by a promoter-containing left monomer fused to an Alu-unrelated downstream moiety. Autonomous Pol III transcription was also revealed for Alus nested within Pol II-transcribed genes. The ability to investigate Alu transcriptomes at single-locus resolution will facilitate both the identification of novel biologically relevant Alu RNAs and the assessment of Alu expression alteration under pathological conditions.
Collapse
Affiliation(s)
- Anastasia Conti
- Department of Life Sciences, University of Parma, 43124 Parma, Italy Department of Clinical and Experimental Medicine, University of Parma, 43126 Parma, Italy
| | - Davide Carnevali
- Department of Life Sciences, University of Parma, 43124 Parma, Italy
| | - Valentina Bollati
- Department of Clinical Sciences and Community Health, University of Milano and Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via S. Barnaba, 8-20122 Milano, Italy
| | - Silvia Fustinoni
- Department of Clinical Sciences and Community Health, University of Milano and Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Via S. Barnaba, 8-20122 Milano, Italy
| | - Matteo Pellegrini
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA 90095-7239, USA
| | - Giorgio Dieci
- Department of Life Sciences, University of Parma, 43124 Parma, Italy
| |
Collapse
|
25
|
Sokolowski M, DeFreece CB, Servant G, Kines KJ, deHaro DL, Belancio VP. Development of a monoclonal antibody specific to the endonuclease domain of the human LINE-1 ORF2 protein. Mob DNA 2014; 5:29. [PMID: 25606060 PMCID: PMC4279459 DOI: 10.1186/s13100-014-0029-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 11/14/2014] [Indexed: 02/06/2023] Open
Abstract
Background LINE-1 (L1) retrotransposons are common occupants of mammalian genomes representing about a fifth of the genetic content. Ongoing L1 retrotransposition in the germ line and somatic tissues has contributed to structural genomic variations and disease-causing mutations in the human genome. L1 mobilization relies on the function of two, self-encoded proteins, ORF1 and ORF2. The ORF2 protein contains two characterized domains: endonuclease and reverse transcriptase. Results Using a bacterially purified endonuclease domain of the human L1 ORF2 protein, we have generated a monoclonal antibody specific to the human ORF2 protein. We determined that the epitope recognized by this monoclonal antibody includes amino acid 205, which is required for the function of the L1 ORF2 protein endonuclease. Using an in vitro L1 cleavage assay, we demonstrate that the monoclonal anti-ORF2 protein antibody partially inhibits L1 endonuclease activity without having any effect on the in vitro activity of the human AP endonuclease. Conclusions Overall, our data demonstrate that this anti-ORF2 protein monoclonal antibody is a useful tool for human L1-related studies and that it provides a rationale for the development of antibody-based inhibitors of L1-induced damage. Electronic supplementary material The online version of this article (doi:10.1186/s13100-014-0029-x) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Mark Sokolowski
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, and Tulane Center for Aging, New Orleans, LA 70112 USA
| | - Cecily B DeFreece
- Department of Biology, Xavier University, 1 Drexel Drive, Box 85, New Orleans, LA 70125-7918 USA
| | - Geraldine Servant
- Department of Epidemiology, Tulane School of Public Health, Tulane Cancer Center, New Orleans, LA 70112 USA
| | - Kristine J Kines
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, and Tulane Center for Aging, New Orleans, LA 70112 USA
| | - Dawn L deHaro
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, and Tulane Center for Aging, New Orleans, LA 70112 USA
| | - Victoria P Belancio
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, and Tulane Center for Aging, New Orleans, LA 70112 USA
| |
Collapse
|
26
|
deHaro D, Kines KJ, Sokolowski M, Dauchy RT, Streva VA, Hill SM, Hanifin JP, Brainard GC, Blask DE, Belancio VP. Regulation of L1 expression and retrotransposition by melatonin and its receptor: implications for cancer risk associated with light exposure at night. Nucleic Acids Res 2014; 42:7694-707. [PMID: 24914052 PMCID: PMC4081101 DOI: 10.1093/nar/gku503] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 04/30/2014] [Accepted: 05/19/2014] [Indexed: 12/17/2022] Open
Abstract
Expression of long interspersed element-1 (L1) is upregulated in many human malignancies. L1 can introduce genomic instability via insertional mutagenesis and DNA double-strand breaks, both of which may promote cancer. Light exposure at night, a recently recognized carcinogen, is associated with an increased risk of cancer in shift workers. We report that melatonin receptor 1 inhibits mobilization of L1 in cultured cells through downregulation of L1 mRNA and ORF1 protein. The addition of melatonin receptor antagonists abolishes the MT1 effect on retrotransposition in a dose-dependent manner. Furthermore, melatonin-rich, but not melatonin-poor, human blood collected at different times during the circadian cycle suppresses endogenous L1 mRNA during in situ perfusion of tissue-isolated xenografts of human cancer. Supplementation of human blood with exogenous melatonin or melatonin receptor antagonist during the in situ perfusion establishes a receptor-mediated action of melatonin on L1 expression. Combined tissue culture and in vivo data support that environmental light exposure of the host regulates expression of L1 elements in tumors. Our data imply that light-induced suppression of melatonin production in shift workers may increase L1-induced genomic instability in their genomes and suggest a possible connection between L1 activity and increased incidence of cancer associated with circadian disruption.
Collapse
Affiliation(s)
- Dawn deHaro
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, New Orleans, LA 70115, USA Tulane Center for Aging, New Orleans, LA 70112, USA
| | - Kristine J Kines
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, New Orleans, LA 70115, USA Tulane Center for Aging, New Orleans, LA 70112, USA
| | - Mark Sokolowski
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, New Orleans, LA 70115, USA Tulane Center for Aging, New Orleans, LA 70112, USA
| | - Robert T Dauchy
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, New Orleans, LA 70115, USA
| | - Vincent A Streva
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, New Orleans, LA 70115, USA
| | - Steven M Hill
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, New Orleans, LA 70115, USA
| | - John P Hanifin
- Department of Neurology, Thomas Jefferson University, Jefferson Medical College, Philadelphia, PA 19107, USA
| | - George C Brainard
- Department of Neurology, Thomas Jefferson University, Jefferson Medical College, Philadelphia, PA 19107, USA
| | - David E Blask
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, New Orleans, LA 70115, USA
| | - Victoria P Belancio
- Department of Structural and Cellular Biology, Tulane School of Medicine, Tulane Cancer Center, New Orleans, LA 70115, USA Tulane Center for Aging, New Orleans, LA 70112, USA
| |
Collapse
|
27
|
Schulman AH. Retrotransposon replication in plants. Curr Opin Virol 2013; 3:604-14. [PMID: 24035277 DOI: 10.1016/j.coviro.2013.08.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 08/16/2013] [Accepted: 08/19/2013] [Indexed: 12/31/2022]
Abstract
Retrotransposons comprise the bulk of large plant genomes, replicating via an RNA intermediate whereby the original, integrated element remains in place. Of the two main orders, the LTR retrotransposons considerably outnumber the LINEs. LINEs integrate into target sites simultaneously with the RNA transcript being copied into cDNA by target-primed reverse transcription. LTR retrotransposon replication is basically equivalent to the intracellular phase of retroviral life cycles. The envelope gene giving extracellular mobility to retroviruses is in fact widespread in plants and their retrotransposons. Evolutionary analyses of the retrotransposons and retroviruses suggest that both form an ancient monophyletic group. The particular adaptations of LTR retrotransposons to plant life cycles enabling their success remain to be clarified.
Collapse
Affiliation(s)
- Alan H Schulman
- Institute of Biotechnology, Viikki Biocenter, University of Helsinki, P.O. Box 65, Helsinki FIN-00014, Finland; Biotechnology and Food Research, MTT Agrifood Research Finland, Jokioinen FIN-31600, Finland.
| |
Collapse
|
28
|
Terasaki N, Goodier JL, Cheung LE, Wang YJ, Kajikawa M, Kazazian HH, Okada N. In vitro screening for compounds that enhance human L1 mobilization. PLoS One 2013; 8:e74629. [PMID: 24040300 PMCID: PMC3770661 DOI: 10.1371/journal.pone.0074629] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 08/05/2013] [Indexed: 12/31/2022] Open
Abstract
The Long interspersed element 1 (LINE1 or L1) retrotransposon constitutes 17% of the human genome. There are currently 80-100 human L1 elements that are thought to be active in any diploid human genome. These elements can mobilize into new locations of the genome, resulting in changes in genomic information. Active L1s are thus considered to be a type of endogenous mutagen, and L1 insertions can cause disease. Certain stresses, such as gamma radiation, oxidative stress, and treatment with some agents, can induce transcription and/or mobilization of retrotransposons. In this study, we used a reporter gene assay in HepG2 cells to screen compounds for the potential to enhance the transcription of human L1. We assessed 95 compounds including genotoxic agents, substances that induce cellular stress, and commercially available drugs. Treatment with 15 compounds increased the L1 promoter activity by >1.5-fold (p<0.05) after 6 or 24 hours of treatment. In particular, genotoxic agents (benzo[a]pyrene, camptothecin, cytochalasin D, merbarone, and vinblastine), PPARα agonists (bezafibrate and fenofibrate), and non-steroidal anti-inflammatory drugs (diflunisal, flufenamic acid, salicylamide, and sulindac) induced L1 promoter activity. To examine their effects on L1 retrotransposition, we developed a high-throughput real-time retrotransposition assay using a novel secreted Gaussia luciferase reporter cassette. Three compounds (etomoxir, WY-14643, and salicylamide) produced a significant enhancement in L1 retrotransposition. This is the first study to report the effects of a wide variety of compounds on L1 transcription and retrotransposition. These results suggest that certain chemical- and drug-induced stresses might have the potential to cause genomic mutations by inducing L1 mobilization. Thus, the risk of induced L1 transcription and retrotransposition should be considered during drug safety evaluation and environmental risk assessments of chemicals.
Collapse
Affiliation(s)
- Natsuko Terasaki
- Department of Biological Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
| | - John L. Goodier
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Ling E. Cheung
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Yue J. Wang
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Masaki Kajikawa
- Department of Biological Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
| | - Haig H. Kazazian
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Norihiro Okada
- Department of Biological Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
- * E-mail:
| |
Collapse
|
29
|
RNA-Mediated Gene Duplication and Retroposons: Retrogenes, LINEs, SINEs, and Sequence Specificity. INTERNATIONAL JOURNAL OF EVOLUTIONARY BIOLOGY 2013; 2013:424726. [PMID: 23984183 PMCID: PMC3747384 DOI: 10.1155/2013/424726] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 07/01/2013] [Indexed: 11/18/2022]
Abstract
A substantial number of “retrogenes” that are derived from the mRNA of various intron-containing genes have been reported. A class of mammalian retroposons, long interspersed element-1 (LINE1, L1), has been shown to be involved in the reverse transcription of retrogenes (or processed pseudogenes) and non-autonomous short interspersed elements (SINEs). The 3′-end sequences of various SINEs originated from a corresponding LINE. As the 3′-untranslated regions of several LINEs are essential for retroposition, these LINEs presumably require “stringent” recognition of the 3′-end sequence of the RNA template. However, the 3′-ends of mammalian L1s do not exhibit any similarity to SINEs, except for the presence of 3′-poly(A) repeats. Since the 3′-poly(A) repeats of L1 and Alu SINE are critical for their retroposition, L1 probably recognizes the poly(A) repeats, thereby mobilizing not only Alu SINE but also cytosolic mRNA. Many flowering plants only harbor L1-clade LINEs and a significant number of SINEs with poly(A) repeats, but no homology to the LINEs. Moreover, processed pseudogenes have also been found in flowering plants. I propose that the ancestral L1-clade LINE in the common ancestor of green plants may have recognized a specific RNA template, with stringent recognition then becoming relaxed during the course of plant evolution.
Collapse
|
30
|
Monot C, Kuciak M, Viollet S, Mir AA, Gabus C, Darlix JL, Cristofari G. The specificity and flexibility of l1 reverse transcription priming at imperfect T-tracts. PLoS Genet 2013; 9:e1003499. [PMID: 23675310 PMCID: PMC3649969 DOI: 10.1371/journal.pgen.1003499] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 03/22/2013] [Indexed: 01/18/2023] Open
Abstract
L1 retrotransposons have a prominent role in reshaping mammalian genomes. To replicate, the L1 ribonucleoprotein particle (RNP) first uses its endonuclease (EN) to nick the genomic DNA. The newly generated DNA end is subsequently used as a primer to initiate reverse transcription within the L1 RNA poly(A) tail, a process known as target-primed reverse transcription (TPRT). Prior studies demonstrated that most L1 insertions occur into sequences related to the L1 EN consensus sequence (degenerate 5′-TTTT/A-3′ sites) and frequently preceded by imperfect T-tracts. However, it is currently unclear whether—and to which degree—the liberated 3′-hydroxyl extremity on the genomic DNA needs to be accessible and complementary to the poly(A) tail of the L1 RNA for efficient priming of reverse transcription. Here, we employed a direct assay for the initiation of L1 reverse transcription to define the molecular rules that guide this process. First, efficient priming is detected with as few as 4 matching nucleotides at the primer 3′ end. Second, L1 RNP can tolerate terminal mismatches if they are compensated within the 10 last bases of the primer by an increased number of matching nucleotides. All terminal mismatches are not equally detrimental to DNA extension, a C being extended at higher levels than an A or a G. Third, efficient priming in the context of duplex DNA requires a 3′ overhang. This suggests the possible existence of additional DNA processing steps, which generate a single-stranded 3′ end to allow L1 reverse transcription. Based on these data we propose that the specificity of L1 reverse transcription initiation contributes, together with the specificity of the initial EN cleavage, to the distribution of new L1 insertions within the human genome. Jumping genes are DNA sequences present in the genome of most living organisms. They contribute to genome dynamics and occasionally result in hereditary genetic diseases or cancer. L1 elements are the only autonomously active jumping genes in the human genome. They replicate through an RNA–mediated copy-and-paste mechanism by cleaving the host genome and then using this new DNA end as a primer to reverse transcribe its own RNA, generating a new L1 DNA copy. The molecular determinants that influence L1 target site choice are not fully understood. Here we present a quantitative assay to measure the influence of DNA target site sequence and structure on the reverse transcription step. By testing more than 65 potential DNA primers, we observe that not all sites are equally extended by the L1 machinery, and we define the rules guiding this process. In particular, we highlight the importance of partial sequence complementarity between the target site and the L1 RNA extremity, but also the high level of flexibility of this process, since detrimental terminal mismatches can be compensated by an increasing number of interacting nucleotides. We propose that this mechanism contributes to the distribution of new L1 insertions within the human genome.
Collapse
Affiliation(s)
- Clément Monot
- INSERM, U1081, Institute for Research on Cancer and Aging, Nice (IRCAN), Nice, France
- CNRS, UMR 7284, Institute for Research on Cancer and Aging, Nice (IRCAN), Nice, France
- University of Nice-Sophia-Antipolis, Faculty of Medicine, Nice, France
| | - Monika Kuciak
- INSERM, U1081, Institute for Research on Cancer and Aging, Nice (IRCAN), Nice, France
- CNRS, UMR 7284, Institute for Research on Cancer and Aging, Nice (IRCAN), Nice, France
- University of Nice-Sophia-Antipolis, Faculty of Medicine, Nice, France
| | - Sébastien Viollet
- INSERM, U1081, Institute for Research on Cancer and Aging, Nice (IRCAN), Nice, France
- CNRS, UMR 7284, Institute for Research on Cancer and Aging, Nice (IRCAN), Nice, France
- University of Nice-Sophia-Antipolis, Faculty of Medicine, Nice, France
| | - Ashfaq Ali Mir
- INSERM, U1081, Institute for Research on Cancer and Aging, Nice (IRCAN), Nice, France
- CNRS, UMR 7284, Institute for Research on Cancer and Aging, Nice (IRCAN), Nice, France
- University of Nice-Sophia-Antipolis, Faculty of Medicine, Nice, France
| | - Caroline Gabus
- Ecole Normale Supérieure de Lyon, Human Virology Department, INSERM U758, Lyon, France
| | - Jean-Luc Darlix
- Ecole Normale Supérieure de Lyon, Human Virology Department, INSERM U758, Lyon, France
| | - Gaël Cristofari
- INSERM, U1081, Institute for Research on Cancer and Aging, Nice (IRCAN), Nice, France
- CNRS, UMR 7284, Institute for Research on Cancer and Aging, Nice (IRCAN), Nice, France
- University of Nice-Sophia-Antipolis, Faculty of Medicine, Nice, France
- * E-mail:
| |
Collapse
|
31
|
Peddigari S, Li PWL, Rabe JL, Martin SL. hnRNPL and nucleolin bind LINE-1 RNA and function as host factors to modulate retrotransposition. Nucleic Acids Res 2013; 41:575-85. [PMID: 23161687 PMCID: PMC3592465 DOI: 10.1093/nar/gks1075] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 10/09/2012] [Accepted: 10/13/2012] [Indexed: 12/18/2022] Open
Abstract
Long INterspersed Element one (LINE-1, or L1), is a widely distributed, autonomous retrotransposon in mammalian genomes. During retrotransposition, L1 RNA functions first as a dicistronic mRNA and then as a template for cDNA synthesis. Previously, we defined internal ribosome entry sequences (IRESs) upstream of both ORFs (ORF1 and ORF2) in the dicistronic mRNA encoded by mouse L1. Here, RNA affinity chromatography was used to isolate cellular proteins that bind these regions of L1 RNA. Four proteins, the heterogeneous nuclear ribonucleoproteins (hnRNPs) R, Q and L, and nucleolin (NCL), appeared to interact specifically with the ORF2 IRES. These were depleted from HeLa cells to examine their effects on L1 IRES-mediated translation and L1 retrotransposition. NCL knockdown specifically reduced the ORF2 IRES activity, L1 and L1-assisted Alu retrotransposition without altering L1 RNA or protein abundance. These findings are consistent with NCL acting as an IRES trans-acting factor (ITAF) for ORF2 translation and hence a positive host factor for L1 retrotransposition. In contrast, hnRNPL knockdown dramatically increased L1 retrotransposition as well as L1 RNA and ORF1 protein, indicating that this cellular protein normally interferes with retrotransposition. Thus, hnRNPL joins a small, but growing list of cellular proteins that are potent negative regulators of L1 retrotransposition.
Collapse
Affiliation(s)
- Suresh Peddigari
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, PO Box 6511, MS 8108, Aurora, CO 80045, USA.
| | | | | | | |
Collapse
|
32
|
Singh DK, Rath PC. Long interspersed nuclear elements (LINEs) show tissue-specific, mosaic genome and methylation-unrestricted, widespread expression of noncoding RNAs in somatic tissues of the rat. RNA Biol 2012; 9:1380-96. [PMID: 23064113 DOI: 10.4161/rna.22402] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We report strong somatic and germ line expression of LINE RNAs in eight different tissues of rat by using a novel ~2.8 kb genomic PstI-LINE DNA (P1-LINE) isolated from the rat brain. P1-LINE is present in a 93 kb LINE-SINE-cluster in sub-telomeric region of chromosome 12 (12p12) and as multiple truncated copies interspersed in all rat chromosomes. P1-LINEs occur as inverted repeats at multiple genomic loci in tissue-specific and mosaic patterns. P1-LINE RNAs are strongly expressed in brain, liver, lungs, heart, kidney, testes, spleen and thymus into large to small heterogeneous RNAs (~5.0 to 0.2 kb) in tissue-specific and dynamic patterns in individual rats. P1-LINE DNA is strongly methylated at CpG-dinucleotides in most genomic copies in all the tissues and weakly hypomethylated in few copies in some tissues. Small (700-75 nt) P1-LINE RNAs expressed in all tissues may be possible precursors for small regulatory RNAs (PIWI-interacting/piRNAs) bioinformatically derived from P1-LINE. The strong and dynamic expression of LINE RNAs from multiple chromosomal loci and the putative piRNAs in somatic tissues of rat under normal physiological conditions may define functional chromosomal domains marked by LINE RNAs as long noncoding RNAs (lncRNAs) unrestricted by DNA methylation. The tissue-specific, dynamic RNA expression and mosaic genomic distribution of LINEs representing a steady-state genomic flux of retrotransposon RNAs suggest for biological role of LINE RNAs as long ncRNAs and small piRNAs in mammalian tissues independent of their cellular fate for translation, reverse-transcription and retrotransposition. This may provide evolutionary advantages to LINEs and mammalian genomes.
Collapse
Affiliation(s)
- Deepak K Singh
- Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | | |
Collapse
|
33
|
Wagstaff BJ, Kroutter EN, Derbes RS, Belancio VP, Roy-Engel AM. Molecular reconstruction of extinct LINE-1 elements and their interaction with nonautonomous elements. Mol Biol Evol 2012; 30:88-99. [PMID: 22918960 PMCID: PMC3525338 DOI: 10.1093/molbev/mss202] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Non-long terminal repeat retroelements continue to impact the human genome through
cis-activity of long interspersed element-1 (LINE-1 or L1) and trans-mobilization of Alu.
Current activity is dominated by modern subfamilies of these elements, leaving behind an
evolutionary graveyard of extinct Alu and L1 subfamilies. Because Alu is a nonautonomous
element that relies on L1 to retrotranspose, there is the possibility that competition
between these elements has driven selection and antagonistic coevolution between Alu and
L1. Through analysis of synonymous versus nonsynonymous codon evolution across L1
subfamilies, we find that the C-terminal ORF2 cys domain experienced a dramatic increase
in amino acid substitution rate in the transition from L1PA5 to L1PA4 subfamilies. This
observation coincides with the previously reported rapid evolution of ORF1 during the same
transition period. Ancestral Alu sequences have been previously reconstructed, as their
short size and ubiquity have made it relatively easy to retrieve consensus sequences from
the human genome. In contrast, creating constructs of extinct L1 copies is a more
laborious task. Here, we report our efforts to recreate and evaluate the
retrotransposition capabilities of two ancestral L1 elements, L1PA4 and L1PA8 that were
active ∼18 and ∼40 Ma, respectively. Relative to the modern L1PA1 subfamily, we
find that both elements are similarly active in a cell culture retrotransposition assay in
HeLa, and both are able to efficiently trans-mobilize Alu elements from several
subfamilies. Although we observe some variation in Alu subfamily retrotransposition
efficiency, any coevolution that may have occurred between LINEs and SINEs is not evident
from these data. Population dynamics and stochastic variation in the number of active
source elements likely play an important role in individual LINE or SINE subfamily
amplification. If coevolution also contributes to changing retrotransposition rates and
the progression of subfamilies, cell factors are likely to play an important mediating
role in changing LINE-SINE interactions over evolutionary time.
Collapse
Affiliation(s)
- Bradley J Wagstaff
- Department of Epidemiology and Tulane Cancer Center, Tulane University, New Orleans, LA, USA
| | | | | | | | | |
Collapse
|
34
|
Wagstaff BJ, Hedges DJ, Derbes RS, Campos Sanchez R, Chiaromonte F, Makova KD, Roy-Engel AM. Rescuing Alu: recovery of new inserts shows LINE-1 preserves Alu activity through A-tail expansion. PLoS Genet 2012; 8:e1002842. [PMID: 22912586 PMCID: PMC3415434 DOI: 10.1371/journal.pgen.1002842] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 05/30/2012] [Indexed: 12/15/2022] Open
Abstract
Alu elements are trans-mobilized by the autonomous non-LTR retroelement, LINE-1 (L1). Alu-induced insertion mutagenesis contributes to about 0.1% human genetic disease and is responsible for the majority of the documented instances of human retroelement insertion-induced disease. Here we introduce a SINE recovery method that provides a complementary approach for comprehensive analysis of the impact and biological mechanisms of Alu retrotransposition. Using this approach, we recovered 226 de novo tagged Alu inserts in HeLa cells. Our analysis reveals that in human cells marked Alu inserts driven by either exogenously supplied full length L1 or ORF2 protein are indistinguishable. Four percent of de novo Alu inserts were associated with genomic deletions and rearrangements and lacked the hallmarks of retrotransposition. In contrast to L1 inserts, 5′ truncations of Alu inserts are rare, as most of the recovered inserts (96.5%) are full length. De novo Alus show a random pattern of insertion across chromosomes, but further characterization revealed an Alu insertion bias exists favoring insertion near other SINEs, highly conserved elements, with almost 60% landing within genes. De novo Alu inserts show no evidence of RNA editing. Priming for reverse transcription rarely occurred within the first 20 bp (most 5′) of the A-tail. The A-tails of recovered inserts show significant expansion, with many at least doubling in length. Sequence manipulation of the construct led to the demonstration that the A-tail expansion likely occurs during insertion due to slippage by the L1 ORF2 protein. We postulate that the A-tail expansion directly impacts Alu evolution by reintroducing new active source elements to counteract the natural loss of active Alus and minimizing Alu extinction. SINEs are mobile elements that are found ubiquitously throughout a large diversity of genomes from plants to mammals. The human SINE, Alu, is among the most successful mobile elements, with more than one million copies in the genome. Due to its high activity and ability to insert throughout the genome, Alu retrotransposition is responsible for the majority of diseases reported to be caused by mobile element activity. To further evaluate the genomic impact of SINEs, we recovered and characterized over 200 de novo Alu inserts under controlled conditions. Our data reinforce observations on the mutagenic potential of Alu, with newly retrotransposed Alu elements favoring insertion into genic and highly conserved elements. Alu-mediated deletions and rearrangements are infrequent and lack the typical hallmarks of TPRT retrotransposition, suggesting the use of an alternate method for resolving retrotransposition intermediates or an atypical insertion mechanism. Our data also provide novel insights into SINE retrotransposition biology. We found that slippage of L1 ORF2 protein during reverse transcription expands the A-tails of de novo insertions. We propose that the L1 ORF2 protein plays a major role in minimizing Alu extinction by reintroducing active Alu elements to counter the natural loss of Alu source elements.
Collapse
Affiliation(s)
- Bradley J. Wagstaff
- Tulane Cancer Center, Department of Epidemiology, Tulane University, New Orleans, Louisiana, United States of America
| | - Dale J. Hedges
- Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Rebecca S. Derbes
- Tulane Cancer Center, Department of Epidemiology, Tulane University, New Orleans, Louisiana, United States of America
| | - Rebeca Campos Sanchez
- Department of Biology, Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Francesca Chiaromonte
- Department of Biology, Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Kateryna D. Makova
- Department of Biology, Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Astrid M. Roy-Engel
- Tulane Cancer Center, Department of Epidemiology, Tulane University, New Orleans, Louisiana, United States of America
- * E-mail:
| |
Collapse
|
35
|
Ashida H, Asai K, Hamada M. Shape-based alignment of genomic landscapes in multi-scale resolution. Nucleic Acids Res 2012; 40:6435-48. [PMID: 22561376 PMCID: PMC3413149 DOI: 10.1093/nar/gks354] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Due to dramatic advances in DNA technology, quantitative measures of annotation data can now be obtained in continuous coordinates across the entire genome, allowing various heterogeneous ‘genomic landscapes’ to emerge. Although much effort has been devoted to comparing DNA sequences, not much attention has been given to comparing these large quantities of data comprehensively. In this article, we introduce a method for rapidly detecting local regions that show high correlations between genomic landscapes. We overcame the size problem for genome-wide data by converting the data into series of symbols and then carrying out sequence alignment. We also decomposed the oscillation of the landscape data into different frequency bands before analysis, since the real genomic landscape is a mixture of embedded and confounded biological processes working at different scales in the cell nucleus. To verify the usefulness and generality of our method, we applied our approach to well investigated landscapes from the human genome, including several histone modifications. Furthermore, by applying our method to over 20 genomic landscapes in human and 12 in mouse, we found that DNA replication timing and the density of Alu insertions are highly correlated genome-wide in both species, even though the Alu elements have amplified independently in the two genomes. To our knowledge, this is the first method to align genomic landscapes at multiple scales according to their shape.
Collapse
Affiliation(s)
- Hiroki Ashida
- Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8561, Japan.
| | | | | |
Collapse
|
36
|
Roy-Engel AM. LINEs, SINEs and other retroelements: do birds of a feather flock together? Front Biosci (Landmark Ed) 2012; 17:1345-61. [PMID: 22201808 DOI: 10.2741/3991] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Mobile elements account for almost half of the mass of the human genome. Only the retroelements from the non-LTR (long terminal repeat) retrotransposon family, which include the LINE-1 (L1) and its non-autonomous partners, are currently active and contributing to new insertions. Although these elements seem to share the same basic amplification mechanism, the activity and success of the different types of retroelements varies. For example, Alu-induced mutagenesis is responsible for the majority of the documented instances of human disease induced by insertion of retroelements. Using copy number in mammals as an indicator, some SINEs have been vastly more successful than other retroelements, such as the retropseudogenes and even L1, likely due to differences in post-insertion selection and ability to overcome cellular controls. SINE and LINE integration can be differentially influenced by cellular factors, indicating some differences between in their amplification mechanisms. We focus on the known aspects of this group of retroelements and highlight their similarities and differences that may significantly influence their biological impact.
Collapse
Affiliation(s)
- Astrid M Roy-Engel
- Tulane University, Department of Epidemiology, School of Public Health and Tropical Medicine, Tulane Cancer Center, SL-66 1430 Tulane Ave., New Orleans, LA 70112.
| |
Collapse
|
37
|
Kines KJ, Belancio VP. Expressing genes do not forget their LINEs: transposable elements and gene expression. FRONT BIOSCI-LANDMRK 2012; 17:1329-44. [PMID: 22201807 DOI: 10.2741/3990] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Historically the accumulated mass of mammalian transposable elements (TEs), particularly those located within gene boundaries, was viewed as a genetic burden potentially detrimental to the genomic landscape. This notion has been strengthened by the discovery that transposable sequences can alter the architecture of the transcriptome, not only through insertion, but also long after the integration process is completed. Insertions previously considered harmless are now known to impact the expression of host genes via modification of the transcript quality or quantity, transcriptional interference, or by the control of pathways that affect the mRNA life-cycle. Conversely, several examples of the evolutionary advantageous impact of TEs on the host gene structure that diversified the cellular transcriptome are reported. TE-induced changes in gene expression can be tissue- or disease-specific, raising the possibility that the impact of TE sequences may vary during development, among normal cell types, and between normal and disease-affected tissues. The understanding of the rules and abundance of TE-interference with gene expression is in its infancy, and its contribution to human disease and/or evolution remains largely unexplored.
Collapse
Affiliation(s)
- Kristine J Kines
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane University Cancer Center and Tulane Center for Aging
| | | |
Collapse
|
38
|
Abstract
Alu elements are primate-specific repeats and comprise 11% of the human genome. They have wide-ranging influences on gene expression. Their contribution to genome evolution, gene regulation and disease is reviewed.
Collapse
|
39
|
Raiz J, Damert A, Chira S, Held U, Klawitter S, Hamdorf M, Löwer J, Strätling WH, Löwer R, Schumann GG. The non-autonomous retrotransposon SVA is trans-mobilized by the human LINE-1 protein machinery. Nucleic Acids Res 2011; 40:1666-83. [PMID: 22053090 PMCID: PMC3287187 DOI: 10.1093/nar/gkr863] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
SINE-VNTR-Alu (SVA) elements are non-autonomous, hominid-specific non-LTR retrotransposons and distinguished by their organization as composite mobile elements. They represent the evolutionarily youngest, currently active family of human non-LTR retrotransposons, and sporadically generate disease-causing insertions. Since preexisting, genomic SVA sequences are characterized by structural hallmarks of Long Interspersed Elements 1 (LINE-1, L1)-mediated retrotransposition, it has been hypothesized for several years that SVA elements are mobilized by the L1 protein machinery in trans. To test this hypothesis, we developed an SVA retrotransposition reporter assay in cell culture using three different human-specific SVA reporter elements. We demonstrate that SVA elements are mobilized in HeLa cells only in the presence of both L1-encoded proteins, ORF1p and ORF2p. SVA trans-mobilization rates exceeded pseudogene formation frequencies by 12- to 300-fold in HeLa-HA cells, indicating that SVA elements represent a preferred substrate for L1 proteins. Acquisition of an AluSp element increased the trans-mobilization frequency of the SVA reporter element by ~25-fold. Deletion of (CCCTCT)n repeats and Alu-like region of a canonical SVA reporter element caused significant attenuation of the SVA trans-mobilization rate. SVA de novo insertions were predominantly full-length, occurred preferentially in G+C-rich regions, and displayed all features of L1-mediated retrotransposition which are also observed in preexisting genomic SVA insertions.
Collapse
Affiliation(s)
- Julija Raiz
- Section PR2/Retroelements, Division of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Strasse 51-59, D-63225 Langen, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Callahan KE, Hickman AB, Jones CE, Ghirlando R, Furano AV. Polymerization and nucleic acid-binding properties of human L1 ORF1 protein. Nucleic Acids Res 2011; 40:813-27. [PMID: 21937507 PMCID: PMC3258132 DOI: 10.1093/nar/gkr728] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The L1 (LINE 1) retrotransposable element encodes two proteins, ORF1p and ORF2p. ORF2p is the L1 replicase, but the role of ORF1p is unknown. Mouse ORF1p, a coiled-coil-mediated trimer of ∼42-kDa monomers, binds nucleic acids and has nucleic acid chaperone activity. We purified human L1 ORF1p expressed in insect cells and made two findings that significantly advance our knowledge of the protein. First, in the absence of nucleic acids, the protein polymerizes under the very conditions (0.05 M NaCl) that are optimal for high (∼1 nM)-affinity nucleic acid binding. The non-coiled-coil C-terminal half mediates formation of the polymer, an active conformer that is instantly resolved to trimers, or multimers thereof, by nucleic acid. Second, the protein has a biphasic effect on mismatched double-stranded DNA, a proxy chaperone substrate. It protects the duplex from dissociation at 37°C before eventually melting it when largely polymeric. Therefore, polymerization of ORF1p seemingly affects its interaction with nucleic acids. Additionally, polymerization of ORF1p at its translation site could explain the heretofore-inexplicable phenomenon of cis preference-the favored retrotransposition of the actively translated L1 transcript, which is essential for L1 survival.
Collapse
Affiliation(s)
- Kathryn E Callahan
- The Laboratory of Molecular and Cellular Biology, National Institue of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | | | | | |
Collapse
|
41
|
Schmitt K, Guo K, Algaier M, Ruiz A, Cheng F, Qiu J, Wissing S, Santiago ML, Stephens EB. Differential virus restriction patterns of rhesus macaque and human APOBEC3A: implications for lentivirus evolution. Virology 2011; 419:24-42. [PMID: 21868050 DOI: 10.1016/j.virol.2011.07.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 05/17/2011] [Accepted: 07/13/2011] [Indexed: 11/17/2022]
Abstract
The human apolipoprotein B mRNA editing enzyme catalytic peptide-like 3 (APOBEC3; A3) family of proteins (A3A-H) are known to restrict various retroviruses and retroelements, but the full complement of rhesus macaque A3 proteins remains unclear. We report the isolation and characterization of the hA3A homologue from rhesus macaques (rhA3A) and show that the rhesus macaque and human A3 genes are orthologous. RhA3A is expressed at high levels in activated CD4+ T cells, is widely expressed in macaque tissues, and is degraded in the presence of the human immunodeficiency virus (HIV-1) and simian-human immunodeficiency virus (SHIV) genomes. Our results indicate that rhA3A is a potent inhibitor of SHIVΔvif and to a lesser extent HIV-1Δvif. Unlike hA3A, rhA3A did not inhibit adeno-associated virus 2 (AAV-2) replication and L1 retrotransposition. These data suggest an evolutionary switch in primate A3A virus specificity and provide the first evidence that a primate A3A can inhibit lentivirus replication.
Collapse
Affiliation(s)
- Kimberly Schmitt
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Nesterovitch AB, Szanto S, Gonda A, Bardos T, Kis-Toth K, Adarichev VA, Olasz K, Ghassemi-Najad S, Hoffman MD, Tharp MD, Mikecz K, Glant TT. Spontaneous insertion of a b2 element in the ptpn6 gene drives a systemic autoinflammatory disease in mice resembling neutrophilic dermatosis in humans. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:1701-14. [PMID: 21435452 DOI: 10.1016/j.ajpath.2010.12.053] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 12/15/2010] [Accepted: 12/23/2010] [Indexed: 01/01/2023]
Abstract
We found a spontaneous autosomal mutation in a mouse leading to neutrophil infiltration with ulceration in the upper dermis of homozygous offspring. These animals had increased neutrophil numbers, associated with normal lymphocyte count, in peripheral blood and bone marrow, suggesting a myeloproliferative disorder; however, granulocyte precursor proliferation in bone marrow was actually reduced (because circulating neutrophils were less susceptible to apoptosis). Neutrophil infiltration of the skin and other organs and high serum levels of immunoglobulins and autoantibodies, cytokines, and acute-phase proteins were additional abnormalities, all of which could be reduced by high-dose corticosteroid treatment or neutrophil depletion by antibodies. Use of genome-wide screening localized the mutation within an 0.4-Mbp region on mouse chromosome 6. We identified insertion of a B2 element in exon 6 of the Ptpn6 gene (protein tyrosine phosphatase, non-receptor type 6; also known as Shp-1). This insertion involves amino acid substitutions that significantly reduced the enzyme activity in mice homozygous for the mutation. Disease onset was delayed, and the clinical phenotype was milder than the phenotypes of other Ptpn6-mutants described in motheaten (me, mev) mice; we designated this new genotype as Ptpn6(meB2/meB2) and the phenotype as meB2. This new phenotype encompasses an autoinflammatory disease showing similarities to many aspects of the so-called neutrophilic dermatoses, a heterogeneous group of skin diseases with unknown etiology in humans.
Collapse
|
43
|
Hedges DJ, Belancio VP. Restless genomes humans as a model organism for understanding host-retrotransposable element dynamics. ADVANCES IN GENETICS 2011; 73:219-62. [PMID: 21310298 DOI: 10.1016/b978-0-12-380860-8.00006-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Since their initial discovery in maize, there have been various attempts to categorize the relationship between transposable elements (TEs) and their host organisms. These have ranged from TEs being selfish parasites to their role as essential, functional components of organismal biology. Research over the past several decades has, in many respects, only served to complicate the issue even further. On the one hand, investigators have amassed substantial evidence concerning the negative effects that TE-mutagenic activity can have on host genomes and organismal fitness. On the other hand, we find an increasing number of examples, across several taxa, of TEs being incorporated into functional biological roles for their host organism. Some 45% of our own genomes are comprised of TE copies. While many of these copies are dormant, having lost their ability to mobilize, several lineages continue to actively proliferate in modern human populations. With its complement of ancestral and active TEs, the human genome exhibits key aspects of the host-TE dynamic that has played out since early on in organismal evolution. In this review, we examine what insights the particularly well-characterized human system can provide regarding the nature of the host-TE interaction.
Collapse
Affiliation(s)
- Dale J Hedges
- Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | | |
Collapse
|
44
|
Iwabuchi KA, Yamakawa T, Sato Y, Ichisaka T, Takahashi K, Okita K, Yamanaka S. ECAT11/L1td1 is enriched in ESCs and rapidly activated during iPSC generation, but it is dispensable for the maintenance and induction of pluripotency. PLoS One 2011; 6:e20461. [PMID: 21637830 PMCID: PMC3102727 DOI: 10.1371/journal.pone.0020461] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 04/24/2011] [Indexed: 11/30/2022] Open
Abstract
The principal factors that lead to proliferation and pluripotency in embryonic stem cells (ESCs) have been vigorously investigated. However, the global network of factors and their full signaling cascade is still unclear. In this study, we found that ECAT11 (L1td1) is one of the ESC-associated transcripts harboring a truncated fragment of ORF-1, a component of theL1 retrotransposable element. We generated an ECAT11 knock-in mouse by replacing its coding region with green fluorescent protein. In the early stage of development, the fluorescence was observed at the inner cell mass of blastocysts and epiblasts. Despite this specific expression, ECAT11-null mice grow normally and are fertile. In addition, ECAT11 was dispensable for both the proliferation and pluripotency of ESCs.We found rapid and robust activation of ECAT11 in fibroblasts after the forced expression of transcription factors that can give rise pluripotency in somatic cells.However, iPS cells could be established from ECAT11-null fibroblasts. Our data demonstrate thedispensability of ECAT11/L1td1 in pluripotency, despite its specific expression.
Collapse
Affiliation(s)
- Kumiko A. Iwabuchi
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
- Department of Stem Cell Biology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
| | - Tatsuya Yamakawa
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
- Department of Stem Cell Biology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
| | - Yoshiko Sato
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
| | - Tomoko Ichisaka
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
| | - Kazutoshi Takahashi
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
| | - Keisuke Okita
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
| | - Shinya Yamanaka
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
- Department of Stem Cell Biology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
- Yamanaka iPS Cell Special Project, Japan Science and Technology Agency, Kawaguchi, Japan
- Gladstone Institute of Cardiovascular Disease, San Francisco, California, United States of America
- * E-mail:
| |
Collapse
|
45
|
Wagstaff BJ, Barnerβoi M, Roy-Engel AM. Evolutionary conservation of the functional modularity of primate and murine LINE-1 elements. PLoS One 2011; 6:e19672. [PMID: 21572950 PMCID: PMC3091869 DOI: 10.1371/journal.pone.0019672] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 04/03/2011] [Indexed: 11/18/2022] Open
Abstract
LINE-1 (L1) retroelements emerged in mammalian genomes over 80 million years ago with a few dominant subfamilies amplifying over discrete time periods that led to distinct human and mouse L1 lineages. We evaluated the functional conservation of L1 sequences by comparing retrotransposition rates of chimeric human-rodent L1 constructs to their parental L1 counterparts. Although amino acid conservation varies from ∼35% to 63% for the L1 ORF1p and ORF2p, most human and mouse L1 sequences can be functionally exchanged. Replacing either ORF1 or ORF2 to create chimeric human-mouse L1 elements did not adversely affect retrotransposition. The mouse ORF2p retains retrotransposition-competency to support both Alu and L1 mobilization when any of the domain sequences we evaluated were substituted with human counterparts. However, the substitution of portions of the mouse cys-domain into the human ORF2p reduces both L1 retrotransposition and Alu trans-mobilization by 200–1000 fold. The observed loss of ORF2p function is independent of the endonuclease or reverse transcriptase activities of ORF2p and RNA interaction required for reverse transcription. In addition, the loss of function is physically separate from the cysteine-rich motif sequence previously shown to be required for RNP formation. Our data suggest an additional role of the less characterized carboxy-terminus of the L1 ORF2 protein by demonstrating that this domain, in addition to mediating RNP interaction(s), provides an independent and required function for the retroelement amplification process. Our experiments show a functional modularity of most of the LINE sequences. However, divergent evolution of interactions within L1 has led to non-reciprocal incompatibilities between human and mouse ORF2 cys-domain sequences.
Collapse
Affiliation(s)
- Bradley J. Wagstaff
- Tulane Cancer Center, Department of Epidemiology, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Miriam Barnerβoi
- Tulane Cancer Center, Department of Epidemiology, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Astrid M. Roy-Engel
- Tulane Cancer Center, Department of Epidemiology, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- * E-mail:
| |
Collapse
|
46
|
Kapelinskaya TV, Kagramanova AS, Korolev AL, Mukha DV. First open reading frame protein (ORF1p) of the Blattella germanica R1 retroposon and phylogenetically close GAG-like proteins of insects and fungi contain RRM domains. RUSS J GENET+ 2011. [DOI: 10.1134/s1022795410121038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
47
|
Xie Y, Rosser JM, Thompson TL, Boeke JD, An W. Characterization of L1 retrotransposition with high-throughput dual-luciferase assays. Nucleic Acids Res 2010; 39:e16. [PMID: 21071410 PMCID: PMC3035435 DOI: 10.1093/nar/gkq1076] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Recent studies employing genome-wide approaches have provided an unprecedented view of the scope of L1 activities on structural variations in the human genome, and further reinforced the role of L1s as one of the major driving forces behind human genome evolution. The rapid identification of novel L1 elements by these high-throughput approaches demands improved L1 functional assays. However, the existing assays use antibiotic selection markers or fluorescent proteins as reporters; neither is amenable to miniaturization. To increase assay sensitivity and throughput, we have developed a third generation assay by using dual-luciferase reporters, in which firefly luciferase is used as the retrotransposition indicator and Renilla luciferase is encoded on the same or separate plasmid for normalization. This novel assay is highly sensitive and has a broad dynamic range. Quantitative data with high signal-to-noise ratios can be obtained from 24- up to 96-well plates in 2–4 days after transfection. Using the dual-luciferase assays, we have characterized profiles of retrotransposition by various human and mouse L1 elements, and detailed the kinetics of L1 retrotransposition in cultured cells. Its high-throughput and short assay timeframe make it well suited for routine tests as well as large-scale screening efforts.
Collapse
Affiliation(s)
- Yi Xie
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA
| | | | | | | | | |
Collapse
|
48
|
Martin SL. Nucleic acid chaperone properties of ORF1p from the non-LTR retrotransposon, LINE-1. RNA Biol 2010; 7:706-11. [PMID: 21045547 DOI: 10.4161/rna.7.6.13766] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Long interspersed element-1 (LINE-1, or L1) is a non-long terminal repeat (LTR) retrotransposon that has amplified to hundreds of thousands of copies in mammalian evolution. A small number of the individual copies of L1 are active retrotransposons which are presently replicating in most species, including humans and mice. L1 retrotransposition begins with transcription of an active element and ends with a newly inserted cDNA copy, a process which requires the two element-encoded proteins to act in cis on the L1 RNA. The ORF1 protein (ORF1p) is a high-affinity, non-sequence-specific RNA binding protein with nucleic acid chaperone activity, whereas the ORF2 protein (ORF2p) supplies the enzymatic activities for cDNA synthesis. This article reviews the nucleic acid chaperone properties of ORF1p in the context of L1 retrotransposition.
Collapse
Affiliation(s)
- Sandra L Martin
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA.
| |
Collapse
|
49
|
Kojima KK. Different integration site structures between L1 protein-mediated retrotransposition in cis and retrotransposition in trans. Mob DNA 2010; 1:17. [PMID: 20615209 PMCID: PMC2912911 DOI: 10.1186/1759-8753-1-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Accepted: 07/08/2010] [Indexed: 11/10/2022] Open
Abstract
Background Long interspersed nuclear element-1 (LINE-1 or L1) is a dominant repetitive sequence in the human genome. Besides mediating its own retrotransposition, L1 can mobilize Alu and messenger RNA (mRNA) in trans, and probably also SVA and non-coding RNA. The structures of L1 copies and trans-mobilized retrocopies are variable and can be classified into three categories: full-length; 5'-truncated; and 5'-inverted insertions. These structures may be generated by different 5' integration mechanisms. Results In this study, a method to correctly characterize insertions with short target site duplications (TSDs) is developed and extranucleotides, TSDs and microhomologies (MHs) at junctions were analysed for the three types of insertions. Only 5'-truncated L1 insertions were found to be associated with short TSDs. Both full-length and 5'-truncated retrotransposed sequences in trans, including Alu, SVA and mRNA retrocopies and also full-length and 5'-inverted L1, were not associated with short TSDs, indicating the difference of 5' attachment between retrotransposition in cis and retrotransposition in trans. Target sequence analysis suggested that short TSDs were generated in an L1 endonuclease-dependent manner. The MHs were longer for 5'-inverted L1 than for 5'-truncated L1, indicating less dependence on annealing in 5'-truncated L1 insertions. Conclusions The results suggest that insertions flanked by short TSDs occur more often coupled with the insertion of 5'-truncated L1 than with those of other types of insertions in vivo. The method used in this study can be used to characterize elements without any apparent boundary structures.
Collapse
Affiliation(s)
- Kenji K Kojima
- Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-B-21 Nagatsuta-Cho, Midori-Ku, Yokohama, Kanagawa 226-8501, Japan.
| |
Collapse
|
50
|
Belancio VP, Roy-Engel AM, Deininger PL. All y'all need to know 'bout retroelements in cancer. Semin Cancer Biol 2010; 20:200-10. [PMID: 20600922 DOI: 10.1016/j.semcancer.2010.06.001] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Revised: 06/14/2010] [Accepted: 06/17/2010] [Indexed: 01/08/2023]
Abstract
Genetic instability is one of the principal hallmarks and causative factors in cancer. Human transposable elements (TE) have been reported to cause human diseases, including several types of cancer through insertional mutagenesis of genes critical for preventing or driving malignant transformation. In addition to retrotransposition-associated mutagenesis, TEs have been found to contribute even more genomic rearrangements through non-allelic homologous recombination. TEs also have the potential to generate a wide range of mutations derivation of which is difficult to directly trace to mobile elements, including double strand breaks that may trigger mutagenic genomic rearrangements. Genome-wide hypomethylation of TE promoters and significantly elevated TE expression in almost all human cancers often accompanied by the loss of critical DNA sensing and repair pathways suggests that the negative impact of mobile elements on genome stability should increase as human tumors evolve. The biological consequences of elevated retroelement expression, such as the rate of their amplification, in human cancers remain obscure, particularly, how this increase translates into disease-relevant mutations. This review is focused on the cellular mechanisms that control human TE-associated mutagenesis in cancer and summarizes the current understanding of TE contribution to genetic instability in human malignancies.
Collapse
Affiliation(s)
- Victoria P Belancio
- Tulane University, Department of Structural and Cellular Biology, School of Medicine, Tulane Cancer Center and Tulane Center for Aging, New Orleans, LA 70112, USA
| | | | | |
Collapse
|