1
|
Lié O, Renault S, Augé-Gouillou C. SETMAR, a case of primate co-opted genes: towards new perspectives. Mob DNA 2022; 13:9. [PMID: 35395947 PMCID: PMC8994322 DOI: 10.1186/s13100-022-00267-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Accepted: 03/28/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND We carry out a review of the history and biological activities of one domesticated gene in higher primates, SETMAR, by discussing current controversies. Our purpose is to open a new outlook that will serve as a framework for future work about SETMAR, possibly in the field of cognition development. MAIN BODY What is newly important about SETMAR can be summarized as follows: (1) the whole protein sequence is under strong purifying pressure; (2) its role is to strengthen existing biological functions rather than to provide new ones; (3) it displays a tissue-specific pattern of expression, at least for the alternative-splicing it undergoes. Studies reported here demonstrate that SETMAR protein(s) may be involved in essential networks regulating replication, transcription and translation. Moreover, during embryogenesis, SETMAR appears to contribute to brain development. SHORT CONCLUSION Our review underlines for the first time that SETMAR directly interacts with genes involved in brain functions related to vocalization and vocal learning. These findings pave the way for future works regarding SETMAR and the development of cognitive abilities in higher primates.
Collapse
Affiliation(s)
- Oriane Lié
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France.,iBrain, Team Neurogenomics and Neuronal physiopathology, Faculty of Medicine, 10 Bd Tonnellé, Cedex 1, 37032, Tours, France
| | - Sylvaine Renault
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France.,iBrain, Team Neurogenomics and Neuronal physiopathology, Faculty of Medicine, 10 Bd Tonnellé, Cedex 1, 37032, Tours, France
| | - Corinne Augé-Gouillou
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France. .,iBrain, Team Neurogenomics and Neuronal physiopathology, Faculty of Medicine, 10 Bd Tonnellé, Cedex 1, 37032, Tours, France.
| |
Collapse
|
2
|
Structural and genome-wide analyses suggest that transposon-derived protein SETMAR alters transcription and splicing. J Biol Chem 2022; 298:101894. [PMID: 35378129 PMCID: PMC9062482 DOI: 10.1016/j.jbc.2022.101894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 03/25/2022] [Accepted: 03/26/2022] [Indexed: 11/22/2022] Open
Abstract
Extensive portions of the human genome have unknown function, including those derived from transposable elements. One such element, the DNA transposon Hsmar1, entered the primate lineage approximately 50 million years ago leaving behind terminal inverted repeat (TIR) sequences and a single intact copy of the Hsmar1 transposase, which retains its ancestral TIR-DNA-binding activity, and is fused with a lysine methyltransferase SET domain to constitute the chimeric SETMAR gene. Here, we provide a structural basis for recognition of TIRs by SETMAR and investigate the function of SETMAR through genome-wide approaches. As elucidated in our 2.37 Å crystal structure, SETMAR forms a dimeric complex with each DNA-binding domain bound specifically to TIR-DNA through the formation of 32 hydrogen bonds. We found that SETMAR recognizes primarily TIR sequences (∼5000 sites) within the human genome as assessed by chromatin immunoprecipitation sequencing analysis. In two SETMAR KO cell lines, we identified 163 shared differentially expressed genes and 233 shared alternative splicing events. Among these genes are several pre–mRNA-splicing factors, transcription factors, and genes associated with neuronal function, and one alternatively spliced primate-specific gene, TMEM14B, which has been identified as a marker for neocortex expansion associated with brain evolution. Taken together, our results suggest a model in which SETMAR impacts differential expression and alternative splicing of genes associated with transcription and neuronal function, potentially through both its TIR-specific DNA-binding and lysine methyltransferase activities, consistent with a role for SETMAR in simian primate development.
Collapse
|
3
|
Zidi M, Denis F, Klai K, Chénais B, Caruso A, Djebbi S, Mezghani M, Casse N. Genome-wide characterization of Mariner-like transposons and their derived MITEs in the Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae). G3 (BETHESDA, MD.) 2021; 11:jkab287. [PMID: 34849769 PMCID: PMC8664452 DOI: 10.1093/g3journal/jkab287] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/28/2021] [Indexed: 12/02/2022]
Abstract
The whitefly, Bemisia tabaci is a hemipteran pest of vegetable crops vectoring a broad category of viruses. Currently, this insect pest showed a high adaptability and resistance to almost all the chemical compounds commonly used for its control. In many cases, transposable elements (TEs) contributed to the evolution of host genomic plasticity. This study focuses on the annotation of Mariner-like elements (MLEs) and their derived Miniature Inverted repeat Transposable Elements (MITEs) in the genome of B. tabaci. Two full-length MLEs belonging to mauritiana and irritans subfamilies were detected and named Btmar1.1 and Btmar2.1, respectively. Additionally, 548 defective MLE sequences clustering mainly into 19 different Mariner lineages of mauritiana and irritans subfamilies were identified. Each subfamily showed a significant variation in MLE copy number and size. Furthermore, 71 MITEs were identified as MLEs derivatives that could be mobilized via the potentially active transposases encoded by Btmar 1.1 and Btmar2.1. The vast majority of sequences detected in the whitefly genome present unusual terminal inverted repeats (TIRs) of up to 400 bp in length. However, some exceptions are sequences without TIRs. This feature of the MLEs and their derived MITEs in B. tabaci genome that distinguishes them from all the other MLEs so far described in insects, which have TIRs size ranging from 20 to 40 bp. Overall, our study provides an overview of MLEs, especially those with large TIRs, and their related MITEs, as well as diversity of their families, which will provide a better understanding of the evolution and adaptation of the whitefly genome.
Collapse
Affiliation(s)
- Marwa Zidi
- Laboratory of Biochemistry and Biotechnology (LR01ES05), Faculty of Sciences of Tunis, University of Tunis El Manar, 2092 Tunis, Tunisia
- Biologie des Organismes, Stress, Santé, Environnement, Le Mans Université, F-72085 Le Mans, France
| | - Françoise Denis
- Biologie des Organismes, Stress, Santé, Environnement, Le Mans Université, F-72085 Le Mans, France
- Laboratoire BOREA MNHN, CNRS FRE 2030, SU, IRD 207, UCN, UA, 75231 Paris, France
| | - Khouloud Klai
- Laboratory of Biochemistry and Biotechnology (LR01ES05), Faculty of Sciences of Tunis, University of Tunis El Manar, 2092 Tunis, Tunisia
- Biologie des Organismes, Stress, Santé, Environnement, Le Mans Université, F-72085 Le Mans, France
| | - Benoît Chénais
- Biologie des Organismes, Stress, Santé, Environnement, Le Mans Université, F-72085 Le Mans, France
| | - Aurore Caruso
- Biologie des Organismes, Stress, Santé, Environnement, Le Mans Université, F-72085 Le Mans, France
| | - Salma Djebbi
- Laboratory of Biochemistry and Biotechnology (LR01ES05), Faculty of Sciences of Tunis, University of Tunis El Manar, 2092 Tunis, Tunisia
| | - Maha Mezghani
- Laboratory of Biochemistry and Biotechnology (LR01ES05), Faculty of Sciences of Tunis, University of Tunis El Manar, 2092 Tunis, Tunisia
| | - Nathalie Casse
- Biologie des Organismes, Stress, Santé, Environnement, Le Mans Université, F-72085 Le Mans, France
| |
Collapse
|
4
|
Tellier M. Structure, Activity, and Function of SETMAR Protein Lysine Methyltransferase. Life (Basel) 2021; 11:life11121342. [PMID: 34947873 PMCID: PMC8704517 DOI: 10.3390/life11121342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 12/21/2022] Open
Abstract
SETMAR is a protein lysine methyltransferase that is involved in several DNA processes, including DNA repair via the non-homologous end joining (NHEJ) pathway, regulation of gene expression, illegitimate DNA integration, and DNA decatenation. However, SETMAR is an atypical protein lysine methyltransferase since in anthropoid primates, the SET domain is fused to an inactive DNA transposase. The presence of the DNA transposase domain confers to SETMAR a DNA binding activity towards the remnants of its transposable element, which has resulted in the emergence of a gene regulatory function. Both the SET and the DNA transposase domains are involved in the different cellular roles of SETMAR, indicating the presence of novel and specific functions in anthropoid primates. In addition, SETMAR is dysregulated in different types of cancer, indicating a potential pathological role. While some light has been shed on SETMAR functions, more research and new tools are needed to better understand the cellular activities of SETMAR and to investigate the therapeutic potential of SETMAR.
Collapse
Affiliation(s)
- Michael Tellier
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| |
Collapse
|
5
|
Lin L, Sharma A, Yu Q. Recent amplification of microsatellite-associated miniature inverted-repeat transposable elements in the pineapple genome. BMC PLANT BIOLOGY 2021; 21:424. [PMID: 34537020 PMCID: PMC8449440 DOI: 10.1186/s12870-021-03194-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Miniature inverted-repeat transposable elements (MITEs) are non-autonomous DNA transposable elements that play important roles in genome organization and evolution. Genome-wide identification and characterization of MITEs provide essential information for understanding genome structure and evolution. RESULTS We performed genome-wide identification and characterization of MITEs in the pineapple genome. The top two MITE families, accounting for 29.39% of the total MITEs and 3.86% of the pineapple genome, have insertion preference in (TA) n dinucleotide microsatellite regions. We therefore named these MITEs A. comosus microsatellite-associated MITEs (Ac-mMITEs). The two Ac-mMITE families, Ac-mMITE-1 and Ac-mMITE-2, shared sequence similarity in the terminal inverted repeat (TIR) regions, suggesting that these two Ac-mMITE families might be derived from a common or closely related autonomous elements. The Ac-mMITEs are frequently clustered via adjacent insertions. Among the 21,994 full-length Ac-mMITEs, 46.1% of them were present in clusters. By analyzing the Ac-mMITEs without (TA) n microsatellite flanking sequences, we found that Ac-mMITEs were likely derived from Mutator-like DNA transposon. Ac-MITEs showed highly polymorphic insertion sites between cultivated pineapples and their wild relatives. To better understand the evolutionary history of Ac-mMITEs, we filtered and performed comparative analysis on the two distinct groups of Ac-mMITEs, microsatellite-targeting MITEs (mt-MITEs) that are flanked by dinucleotide microsatellites on both sides and mutator-like MITEs (ml-MITEs) that contain 9/10 bp TSDs. Epigenetic analysis revealed a lower level of host-induced silencing on the mt-MITEs in comparison to the ml-MITEs, which partially explained the significantly higher abundance of mt-MITEs in pineapple genome. The mt-MITEs and ml-MITEs exhibited differential insertion preference to gene-related regions and RNA-seq analysis revealed their differential influences on expression regulation of nearby genes. CONCLUSIONS Ac-mMITEs are the most abundant MITEs in the pineapple genome and they were likely derived from Mutator-like DNA transposon. Preferential insertion in (TA) n microsatellite regions of Ac-mMITEs occurred recently and is likely the result of damage-limiting strategy adapted by Ac-mMITEs during co-evolution with their host. Insertion in (TA) n microsatellite regions might also have promoted the amplification of mt-MITEs. In addition, mt-MITEs showed no or negligible impact on nearby gene expression, which may help them escape genome control and lead to their amplification.
Collapse
Affiliation(s)
- Lianyu Lin
- Texas A&M AgriLife Research Center at Dallas, Texas A&M University System, Dallas, TX, 75252, USA
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China
| | - Anupma Sharma
- Texas A&M AgriLife Research Center at Dallas, Texas A&M University System, Dallas, TX, 75252, USA
| | - Qingyi Yu
- Texas A&M AgriLife Research Center at Dallas, Texas A&M University System, Dallas, TX, 75252, USA.
| |
Collapse
|
6
|
Sandoval-Villegas N, Nurieva W, Amberger M, Ivics Z. Contemporary Transposon Tools: A Review and Guide through Mechanisms and Applications of Sleeping Beauty, piggyBac and Tol2 for Genome Engineering. Int J Mol Sci 2021; 22:ijms22105084. [PMID: 34064900 PMCID: PMC8151067 DOI: 10.3390/ijms22105084] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 04/30/2021] [Accepted: 05/05/2021] [Indexed: 01/19/2023] Open
Abstract
Transposons are mobile genetic elements evolved to execute highly efficient integration of their genes into the genomes of their host cells. These natural DNA transfer vehicles have been harnessed as experimental tools for stably introducing a wide variety of foreign DNA sequences, including selectable marker genes, reporters, shRNA expression cassettes, mutagenic gene trap cassettes, and therapeutic gene constructs into the genomes of target cells in a regulated and highly efficient manner. Given that transposon components are typically supplied as naked nucleic acids (DNA and RNA) or recombinant protein, their use is simple, safe, and economically competitive. Thus, transposons enable several avenues for genome manipulations in vertebrates, including transgenesis for the generation of transgenic cells in tissue culture comprising the generation of pluripotent stem cells, the production of germline-transgenic animals for basic and applied research, forward genetic screens for functional gene annotation in model species and therapy of genetic disorders in humans. This review describes the molecular mechanisms involved in transposition reactions of the three most widely used transposon systems currently available (Sleeping Beauty, piggyBac, and Tol2), and discusses the various parameters and considerations pertinent to their experimental use, highlighting the state-of-the-art in transposon technology in diverse genetic applications.
Collapse
Affiliation(s)
| | | | | | - Zoltán Ivics
- Correspondence: ; Tel.: +49-6103-77-6000; Fax: +49-6103-77-1280
| |
Collapse
|
7
|
Antoine-Lorquin A, Arensburger P, Arnaoty A, Asgari S, Batailler M, Beauclair L, Belleannée C, Buisine N, Coustham V, Guyetant S, Helou L, Lecomte T, Pitard B, Stévant I, Bigot Y. Two repeated motifs enriched within some enhancers and origins of replication are bound by SETMAR isoforms in human colon cells. Genomics 2021; 113:1589-1604. [PMID: 33812898 DOI: 10.1016/j.ygeno.2021.03.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 03/25/2021] [Accepted: 03/30/2021] [Indexed: 11/15/2022]
Abstract
Setmar is a gene specific to simian genomes. The function(s) of its isoforms are poorly understood and their existence in healthy tissues remains to be validated. Here we profiled SETMAR expression and its genome-wide binding landscape in colon tissue. We found isoforms V3 and V6 in healthy and tumour colon tissues as well as incell lines. In two colorectal cell lines SETMAR binds to several thousand Hsmar1 and MADE1 terminal ends, transposons mostly located in non-genic regions of active chromatin including in enhancers. It also binds to a 12-bp motifs similar to an inner motif in Hsmar1 and MADE1 terminal ends. This motif is interspersed throughout the genome and is enriched in GC-rich regions as well as in CpG islands that contain constitutive replication origins. It is also found in enhancers other than those associated with Hsmar1 and MADE1. The role of SETMAR in the expression of genes, DNA replication and in DNA repair are discussed.
Collapse
Affiliation(s)
| | - Peter Arensburger
- Biological Sciences Department, California State Polytechnic University, Pomona, CA 91768, - United States
| | - Ahmed Arnaoty
- EA GICC, 7501, CHRU de Tours, 37044 TOURS, Cedex 09, France
| | - Sassan Asgari
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Martine Batailler
- PRC, UMR INRA 0085, CNRS 7247, Centre INRA Val de Loire, 37380 Nouzilly, France
| | - Linda Beauclair
- PRC, UMR INRA 0085, CNRS 7247, Centre INRA Val de Loire, 37380 Nouzilly, France
| | | | - Nicolas Buisine
- UMR CNRS 7221, Muséum National d'Histoire Naturelle, 75005 Paris, France
| | | | - Serge Guyetant
- Tumorothèque du CHRU de Tours, 37044 Tours, Cedex, France
| | - Laura Helou
- PRC, UMR INRA 0085, CNRS 7247, Centre INRA Val de Loire, 37380 Nouzilly, France
| | | | - Bruno Pitard
- Université de Nantes, CNRS ERL6001, Inserm 1232, CRCINA, F-44000 Nantes, France
| | - Isabelle Stévant
- Institut de Génomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon, 1, 46 allée d'Italie, 69364 Lyon, France
| | - Yves Bigot
- PRC, UMR INRA 0085, CNRS 7247, Centre INRA Val de Loire, 37380 Nouzilly, France.
| |
Collapse
|
8
|
Shen D, Song C, Miskey C, Chan S, Guan Z, Sang Y, Wang Y, Chen C, Wang X, Müller F, Ivics Z, Gao B. A native, highly active Tc1/mariner transposon from zebrafish (ZB) offers an efficient genetic manipulation tool for vertebrates. Nucleic Acids Res 2021; 49:2126-2140. [PMID: 33638993 PMCID: PMC7913693 DOI: 10.1093/nar/gkab045] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 01/13/2021] [Accepted: 01/15/2021] [Indexed: 12/18/2022] Open
Abstract
New genetic tools and strategies are currently under development to facilitate functional genomics analyses. Here, we describe an active member of the Tc1/mariner transposon superfamily, named ZB, which invaded the zebrafish genome very recently. ZB exhibits high activity in vertebrate cells, in the range of those of the widely used transposons piggyBac (PB), Sleeping Beauty (SB) and Tol2. ZB has a similar structural organization and target site sequence preference to SB, but a different integration profile with respect to genome-wide preference among mammalian functional annotation features. Namely, ZB displays a preference for integration into transcriptional regulatory regions of genes. Accordingly, we demonstrate the utility of ZB for enhancer trapping in zebrafish embryos and in the mouse germline. These results indicate that ZB may be a powerful tool for genetic manipulation in vertebrate model species.
Collapse
Affiliation(s)
- Dan Shen
- College of Animal Science & Technology, Yangzhou University, Yangzhou, Jiangsu 225009, China
- Division of Medical Biotechnology, Paul Ehrlich Institute, Langen 63225, Germany
| | - Chengyi Song
- College of Animal Science & Technology, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Csaba Miskey
- Division of Medical Biotechnology, Paul Ehrlich Institute, Langen 63225, Germany
| | - Shuheng Chan
- College of Animal Science & Technology, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Zhongxia Guan
- College of Animal Science & Technology, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Yatong Sang
- College of Animal Science & Technology, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Yali Wang
- College of Animal Science & Technology, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Cai Chen
- College of Animal Science & Technology, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Xiaoyan Wang
- College of Animal Science & Technology, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Ferenc Müller
- Institute of Cancer and Genomic Sciences, Birmingham Centre for Genome Biology, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Zoltán Ivics
- Division of Medical Biotechnology, Paul Ehrlich Institute, Langen 63225, Germany
| | - Bo Gao
- College of Animal Science & Technology, Yangzhou University, Yangzhou, Jiangsu 225009, China
| |
Collapse
|
9
|
Ochmann MT, Ivics Z. Jumping Ahead with Sleeping Beauty: Mechanistic Insights into Cut-and-Paste Transposition. Viruses 2021; 13:v13010076. [PMID: 33429848 PMCID: PMC7827188 DOI: 10.3390/v13010076] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/16/2020] [Accepted: 12/28/2020] [Indexed: 12/13/2022] Open
Abstract
Sleeping Beauty (SB) is a transposon system that has been widely used as a genetic engineering tool. Central to the development of any transposon as a research tool is the ability to integrate a foreign piece of DNA into the cellular genome. Driven by the need for efficient transposon-based gene vector systems, extensive studies have largely elucidated the molecular actors and actions taking place during SB transposition. Close transposon relatives and other recombination enzymes, including retroviral integrases, have served as useful models to infer functional information relevant to SB. Recently obtained structural data on the SB transposase enable a direct insight into the workings of this enzyme. These efforts cumulatively allowed the development of novel variants of SB that offer advanced possibilities for genetic engineering due to their hyperactivity, integration deficiency, or targeting capacity. However, many aspects of the process of transposition remain poorly understood and require further investigation. We anticipate that continued investigations into the structure-function relationships of SB transposition will enable the development of new generations of transposition-based vector systems, thereby facilitating the use of SB in preclinical studies and clinical trials.
Collapse
|
10
|
Dupeyron M, Baril T, Bass C, Hayward A. Phylogenetic analysis of the Tc1/mariner superfamily reveals the unexplored diversity of pogo-like elements. Mob DNA 2020; 11:21. [PMID: 32612713 PMCID: PMC7325037 DOI: 10.1186/s13100-020-00212-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 04/08/2020] [Indexed: 01/18/2023] Open
Abstract
Background Tc1/mariner transposons are widespread DNA transposable elements (TEs) that have made important contributions to the evolution of host genomic complexity in metazoans. However, the evolution and diversity of the Tc1/mariner superfamily remains poorly understood. Following recent developments in genome sequencing and the availability of a wealth of new genomes, Tc1/mariner TEs have been identified in many new taxa across the eukaryotic tree of life. To date, the majority of studies focussing on Tc1/mariner elements have considered only a single host lineage or just a small number of host lineages. Thus, much remains to be learnt about the evolution of Tc1/mariner TEs by performing analyses that consider elements that originate from across host diversity. Results We mined the non-redundant database of NCBI using BLASTp searches, with transposase sequences from a diverse set of reference Tc1/mariner elements as queries. A total of 5158 Tc1/mariner elements were retrieved and used to reconstruct evolutionary relationships within the superfamily. The resulting phylogeny is well resolved and includes several new groups of Tc1/mariner elements. In particular, we identify a new family of plant-genome restricted Tc1/mariner elements, which we call PlantMar. We also show that the pogo family is much larger and more diverse than previously appreciated, and we review evidence for a potential revision of its status to become a separate superfamily. Conclusions Our study provides an overview of Tc1-mariner phylogeny and summarises the impressive diversity of Tc1-mariner TEs among sequenced eukaryotes. Tc1/mariner TEs are successful in a wide range of eukaryotes, especially unikonts (the taxonomic supergroup containing Amoebozoa, Opisthokonta, Breviatea, and Apusomonadida). In particular, ecdysozoa, and especially arthropods, emerge as important hosts for Tc1/mariner elements (except the PlantMar family). Meanwhile, the pogo family, which is by far the largest Tc1/mariner family, also includes many elements from fungal and chordate genomes. Moreover, there is evidence of the repeated exaptation of pogo elements in vertebrates, including humans, in addition to the well-known example of CENP-B. Collectively, our findings provide a considerable advancement in understanding of Tc1/mariner elements, and more generally they suggest that much work remains to improve understanding of the diversity and evolution of DNA TEs.
Collapse
Affiliation(s)
- Mathilde Dupeyron
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE UK
| | - Tobias Baril
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE UK
| | - Chris Bass
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE UK
| | - Alexander Hayward
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE UK
| |
Collapse
|
11
|
Kesselring L, Miskey C, Zuliani C, Querques I, Kapitonov V, Laukó A, Fehér A, Palazzo A, Diem T, Lustig J, Sebe A, Wang Y, Dinnyés A, Izsvák Z, Barabas O, Ivics Z. A single amino acid switch converts the Sleeping Beauty transposase into an efficient unidirectional excisionase with utility in stem cell reprogramming. Nucleic Acids Res 2020; 48:316-331. [PMID: 31777924 PMCID: PMC6943129 DOI: 10.1093/nar/gkz1119] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 11/07/2019] [Accepted: 11/22/2019] [Indexed: 12/26/2022] Open
Abstract
The Sleeping Beauty (SB) transposon is an advanced tool for genetic engineering and a useful model to investigate cut-and-paste DNA transposition in vertebrate cells. Here, we identify novel SB transposase mutants that display efficient and canonical excision but practically unmeasurable genomic re-integration. Based on phylogenetic analyses, we establish compensating amino acid replacements that fully rescue the integration defect of these mutants, suggesting epistasis between these amino acid residues. We further show that the transposons excised by the exc+/int− transposase mutants form extrachromosomal circles that cannot undergo a further round of transposition, thereby representing dead-end products of the excision reaction. Finally, we demonstrate the utility of the exc+/int− transposase in cassette removal for the generation of reprogramming factor-free induced pluripotent stem cells. Lack of genomic integration and formation of transposon circles following excision is reminiscent of signal sequence removal during V(D)J recombination, and implies that cut-and-paste DNA transposition can be converted to a unidirectional process by a single amino acid change.
Collapse
Affiliation(s)
- Lisa Kesselring
- Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
| | - Csaba Miskey
- Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
| | - Cecilia Zuliani
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Irma Querques
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Vladimir Kapitonov
- Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
| | | | - Anita Fehér
- BioTalentum Ltd, Gödöllő, 2100 Gödöllő, Hungary
| | - Antonio Palazzo
- Department of Biology, University of Bari 'Aldo Moro', Italy
| | - Tanja Diem
- Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
| | - Janna Lustig
- Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
| | - Attila Sebe
- Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
| | - Yongming Wang
- Mobile DNA, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | | | - Zsuzsanna Izsvák
- Mobile DNA, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Orsolya Barabas
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Zoltán Ivics
- Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
| |
Collapse
|
12
|
Kovač A, Miskey C, Menzel M, Grueso E, Gogol-Döring A, Ivics Z. RNA-guided retargeting of S leeping Beauty transposition in human cells. eLife 2020; 9:e53868. [PMID: 32142408 PMCID: PMC7077980 DOI: 10.7554/elife.53868] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/05/2020] [Indexed: 12/12/2022] Open
Abstract
An ideal tool for gene therapy would enable efficient gene integration at predetermined sites in the human genome. Here we demonstrate biased genome-wide integration of the Sleeping Beauty (SB) transposon by combining it with components of the CRISPR/Cas9 system. We provide proof-of-concept that it is possible to influence the target site selection of SB by fusing it to a catalytically inactive Cas9 (dCas9) and by providing a single guide RNA (sgRNA) against the human Alu retrotransposon. Enrichment of transposon integrations was dependent on the sgRNA, and occurred in an asymmetric pattern with a bias towards sites in a relatively narrow, 300 bp window downstream of the sgRNA targets. Our data indicate that the targeting mechanism specified by CRISPR/Cas9 forces integration into genomic regions that are otherwise poor targets for SB transposition. Future modifications of this technology may allow the development of methods for specific gene insertion for precision genetic engineering.
Collapse
Affiliation(s)
- Adrian Kovač
- Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich InstituteLangenGermany
| | - Csaba Miskey
- Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich InstituteLangenGermany
| | | | - Esther Grueso
- Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich InstituteLangenGermany
| | | | - Zoltán Ivics
- Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich InstituteLangenGermany
| |
Collapse
|
13
|
Tellier M, Chalmers R. Compensating for over-production inhibition of the Hsmar1 transposon in Escherichia coli using a series of constitutive promoters. Mob DNA 2020; 11:5. [PMID: 31938044 PMCID: PMC6954556 DOI: 10.1186/s13100-020-0200-5] [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: 08/06/2019] [Accepted: 01/01/2020] [Indexed: 01/03/2023] Open
Abstract
Background Transposable elements (TEs) are a diverse group of self-mobilizing DNA elements. Transposition has been exploited as a powerful tool for molecular biology and genomics. However, transposition is sometimes limited because of auto-regulatory mechanisms that presumably allow them to cohabit within their hosts without causing excessive genomic damage. The papillation assay provides a powerful visual screen for hyperactive transposases. Transposition is revealed by the activation of a promoter-less lacZ gene when the transposon integrates into a non-essential gene on the host chromosome. Transposition events are detected as small blue speckles, or papillae, on the white background of the main Escherichia coli colony. Results We analysed the parameters of the papillation assay including the strength of the transposase transcriptional and translational signals. To overcome certain limitations of inducible promoters, we constructed a set of vectors based on constitutive promoters of different strengths to widen the range of transposase expression. We characterized and validated our expression vectors with Hsmar1, a member of the mariner transposon family. The highest rate of transposition was observed with the weakest promoters. We then took advantage of our approach to investigate how the level of transposition responds to selected point mutations and the effect of joining the transposase monomers into a single-chain dimer. Conclusions We generated a set of vectors to provide a wide range of transposase expression which will be useful for screening libraries of transposase mutants. The use of weak promoters should allow screening for truly hyperactive transposases rather than those that are simply resistant to auto-regulatory mechanisms, such as overproduction inhibition (OPI). We also found that mutations in the Hsmar1 dimer interface provide resistance to OPI in bacteria, which could be valuable for improving bacterial transposon mutagenesis techniques.
Collapse
Affiliation(s)
- Michael Tellier
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH UK.,2Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE UK
| | - Ronald Chalmers
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH UK
| |
Collapse
|
14
|
Bhatt S, Chalmers R. Targeted DNA transposition in vitro using a dCas9-transposase fusion protein. Nucleic Acids Res 2019; 47:8126-8135. [PMID: 31429873 PMCID: PMC6735945 DOI: 10.1093/nar/gkz552] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/07/2019] [Accepted: 06/11/2019] [Indexed: 12/21/2022] Open
Abstract
Homology-directed genome engineering is limited by transgene size. Although DNA transposons are more efficient with large transgenes, random integrations are potentially mutagenic. Here we present an in vitro mechanistic study that demonstrates efficient Cas9 targeting of the mariner transposon Hsmar1. Integrations were unidirectional and tightly constrained to one side of the sgRNA binding site. Further analysis of the nucleoprotein intermediates demonstrated that the transposase and Cas9 moieties can bind their respective substrates independently or in concert. Kinetic analysis of the reaction in the presence of the Cas9 target-DNA revealed a delay between first and second strand cleavage at the transposon end. This step involves a significant conformational change that may be hindered by the properties of the interdomainal linker. Otherwise, the transposase moiety behaved normally and was proficient for integration in vitro and in Escherichia coli. Specific integration into the lacZ gene in E. coli was obscured by a high background of random integrations. Nevertheless, Cas9 is an attractive candidate for transposon-targeting because it has a high affinity and long dwell-time at its target site. This will facilitate a future optogenetic strategy for the temporal control of integration, which will increase the ratio of targeted to untargeted events.
Collapse
Affiliation(s)
- Shivam Bhatt
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Ronald Chalmers
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| |
Collapse
|
15
|
Tellier M, Chalmers R. Human SETMAR is a DNA sequence-specific histone-methylase with a broad effect on the transcriptome. Nucleic Acids Res 2019; 47:122-133. [PMID: 30329085 PMCID: PMC6326780 DOI: 10.1093/nar/gky937] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 10/12/2018] [Indexed: 12/26/2022] Open
Abstract
Transposons impart dynamism to the genomes they inhabit and their movements frequently rewire the control of nearby genes. Occasionally, their proteins are domesticated when they evolve a new function. SETMAR is a protein methylase with a sequence-specific DNA binding domain. It began to evolve about 50 million years ago when an Hsmar1 transposon integrated downstream of a SET-domain methylase gene. Here we show that the DNA-binding domain of the transposase targets the enzyme to transposon-end remnants and that this is capable of regulating gene expression, dependent on the methylase activity. When SETMAR was modestly overexpressed in human cells, almost 1500 genes changed expression by more than 2-fold (65% up- and 35% down-regulated). These genes were enriched for the KEGG Pathways in Cancer and include several transcription factors important for development and differentiation. Expression of a similar level of a methylase-deficient SETMAR changed the expression of many fewer genes, 77% of which were down-regulated with no significant enrichment of KEGG Pathways. Our data is consistent with a model in which SETMAR is part of an anthropoid primate-specific regulatory network centered on the subset of genes containing a transposon end.
Collapse
Affiliation(s)
- Michael Tellier
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Ronald Chalmers
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| |
Collapse
|
16
|
Ramakrishnan M, Zhou M, Pan C, Hänninen H, Yrjälä K, Vinod KK, Tang D. Affinities of Terminal Inverted Repeats to DNA Binding Domain of Transposase Affect the Transposition Activity of Bamboo Ppmar2 Mariner-Like Element. Int J Mol Sci 2019; 20:ijms20153692. [PMID: 31357686 PMCID: PMC6696609 DOI: 10.3390/ijms20153692] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 07/19/2019] [Accepted: 07/24/2019] [Indexed: 11/16/2022] Open
Abstract
Mariner-like elements (MLE) are a super-family of DNA transposons widespread in animal and plant genomes. Based on their transposition characteristics, such as random insertions and high-frequency heterogeneous transpositions, several MLEs have been developed to be used as tools in gene tagging and gene therapy. Two active MLEs, Ppmar1 and Ppmar2, have previously been identified in moso bamboo (Phyllostachys edulis). Both of these have a preferential insertion affinity to AT-rich region and their insertion sites are close to random in the host genome. In Ppmar2 element, we studied the affinities of terminal inverted repeats (TIRs) to DNA binding domain (DBD) and their influence on the transposition activity. We could identify two putative boxes in the TIRs which play a significant role in defining the TIR's affinities to the DBD. Seven mutated TIRs were constructed, differing in affinities based on similarities with those of other plant MLEs. Gel mobility shift assays showed that the TIR mutants with mutation sites G669A-C671A had significantly higher affinities than the mutants with mutation sites C657T-A660T. The high-affinity TIRs indicated that their transposition frequency was 1.5-2.0 times higher than that of the wild type TIRs in yeast transposition assays. The MLE mutants with low-affinity TIRs had relatively lower transposition frequency from that of wild types. We conclude that TIR affinity to DBD significantly affects the transposition activity of Ppmar2. The mutant MLEs highly active TIRs constructed in this study can be used as a tool for bamboo genetic studies.
Collapse
Affiliation(s)
- Muthusamy Ramakrishnan
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin'an, Hangzhou 311300, Zhejiang, China
| | - Mingbing Zhou
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin'an, Hangzhou 311300, Zhejiang, China.
- Zhejiang Provincial Collaborative Innovation Center for Bamboo Resources and High-Efficiency Utilization, Zhejiang A&F University, Lin'an, Hangzhou 311300, Zhejiang, China.
| | - Chunfang Pan
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin'an, Hangzhou 311300, Zhejiang, China
| | - Heikki Hänninen
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin'an, Hangzhou 311300, Zhejiang, China
| | - Kim Yrjälä
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin'an, Hangzhou 311300, Zhejiang, China
- Department of Forest Sciences, University of Helsinki, 00014 Helsinki, Finland
| | - Kunnummal Kurungara Vinod
- Division of Genetics, ICAR-Indian Agricultural Research Institute, Rice Breeding and Genetics Research Centre, Aduthurai, Tamil Nadu 612101, India
| | - Dingqin Tang
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin'an, Hangzhou 311300, Zhejiang, China
| |
Collapse
|
17
|
Tellier M, Chalmers R. The roles of the human SETMAR (Metnase) protein in illegitimate DNA recombination and non-homologous end joining repair. DNA Repair (Amst) 2019; 80:26-35. [PMID: 31238295 PMCID: PMC6715855 DOI: 10.1016/j.dnarep.2019.06.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/18/2019] [Accepted: 06/18/2019] [Indexed: 02/07/2023]
Abstract
Full length SETMAR expression has no effect on DNA repair and integration in vivo. SETMAR putative nuclease activity is not required in vivo. Separate expression of the SET and MAR domains affects DNA repair and integration. SETMAR isoform with a truncated SET-domain is specific to species containing the MAR domain.
SETMAR is a fusion between a SET-domain methyltransferase gene and a mariner-family transposase gene, which is specific to anthropoid primates. However, the ancestral SET gene is present in all other mammals and birds. SETMAR is reported to be involved in transcriptional regulation and a diverse set of reactions related to DNA repair. Since the transcriptional effects of SETMAR depend on site-specific DNA binding, and are perturbed by inactivating the methyltransferase, we wondered whether we could differentiate the effects of the SET and MAR domains in DNA repair assays. We therefore generated several stable U2OS cell lines expressing either wild type SETMAR or truncation or point mutant variants. We tested these cell lines with in vivo plasmid-based assays to determine the relevance of the different domains and activities of SETMAR in DNA repair. Contrary to previous reports, we found that wild type SETMAR had little to no effect on the rate of cell division, DNA integration into the genome or non-homologous end joining. Also contrary to previous reports, we failed to detect any effect of a strong active-site mutation that should have knocked out the putative nuclease activity of SETMAR.
Collapse
Affiliation(s)
- Michael Tellier
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
| | - Ronald Chalmers
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
| |
Collapse
|
18
|
Palazzo A, Lorusso P, Miskey C, Walisko O, Gerbino A, Marobbio CMT, Ivics Z, Marsano RM. Transcriptionally promiscuous "blurry" promoters in Tc1/ mariner transposons allow transcription in distantly related genomes. Mob DNA 2019; 10:13. [PMID: 30988701 PMCID: PMC6446368 DOI: 10.1186/s13100-019-0155-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 03/26/2019] [Indexed: 12/04/2022] Open
Abstract
Background We have recently described a peculiar feature of the promoters in two Drosophila Tc1-like elements, Bari1 and Bari3. The AT-richness and the presence of weak core-promoter motifs make these promoters, that we have defined “blurry”, able to activate transcription of a reporter gene in cellular systems as diverse as fly, human, yeast and bacteria. In order to clarify whether the blurry promoter is a specific feature of the Bari transposon family, we have extended this study to promoters isolated from three additional DNA transposon and from two additional LTR retrotransposons. Results Here we show that the blurry promoter is also a feature of two vertebrate transposable elements, Sleeping Beauty and Hsmar1, belonging to the Tc1/mariner superfamily. In contrast, this feature is not shared by the promoter of the hobo transposon, which belongs to the hAT superfamily, nor by LTR retrotransposon-derived promoters, which, in general, do not activate transcription when introduced into non-related genomes. Conclusions Our results suggest that the blurry promoter could be a shared feature of the members of the Tc1/mariner superfamily with possible evolutionary and biotechnological implications. Electronic supplementary material The online version of this article (10.1186/s13100-019-0155-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Antonio Palazzo
- 1Department of Biology, University of Bari "Aldo Moro", via Orabona 4, 70125 Bari, Italy.,Present address: Laboratory of Translational Nanotechnology, "Istituto Tumori Giovanni Paolo II" I.R.C.C.S, Viale Orazio Flacco 65, 70125 Bari, Italy
| | - Patrizio Lorusso
- 1Department of Biology, University of Bari "Aldo Moro", via Orabona 4, 70125 Bari, Italy
| | - Csaba Miskey
- 2Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
| | - Oliver Walisko
- 2Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
| | - Andrea Gerbino
- 3Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
| | | | - Zoltán Ivics
- 2Transposition and Genome Engineering, Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
| | | |
Collapse
|
19
|
Renault S, Genty M, Gabori A, Boisneau C, Esnault C, Dugé de Bernonville T, Augé-Gouillou C. The epigenetic regulation of HsMar1, a human DNA transposon. BMC Genet 2019; 20:17. [PMID: 30764754 PMCID: PMC6375154 DOI: 10.1186/s12863-019-0719-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/29/2019] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Both classes of transposable elements (DNA and RNA) are tightly regulated at the transcriptional level leading to the inactivation of transposition via epigenetic mechanisms. Due to the high copies number of these elements, the hypothesis has emerged that their regulation can coordinate a regulatory network of genes. Herein, we investigated whether transposition regulation of HsMar1, a human DNA transposon, differs in presence or absence of endogenous HsMar1 copies. In the case where HsMar1 transposition is regulated, the number of repetitive DNA sequences issued by HsMar1 and distributed in the human genome makes HsMar1 a good candidate to regulate neighboring gene expression by epigenetic mechanisms. RESULTS A recombinant active HsMar1 copy was inserted in HeLa (human) and CHO (hamster) cells and its genomic excision monitored. We show that HsMar1 excision is blocked in HeLa cells, whereas CHO cells are competent to promote HsMar1 excision. We demonstrate that de novo HsMar1 insertions in HeLa cells (human) undergo rapid silencing by cytosine methylation and apposition of H3K9me3 marks, whereas de novo HsMar1 insertions in CHO cells (hamster) are not repressed and enriched in H3K4me3 modifications. The overall analysis of HsMar1 endogenous copies in HeLa cells indicates that neither full-length endogenous inactive copies nor their Inverted Terminal Repeats seem to be specifically silenced, and are, in contrast, devoid of epigenetic marks. Finally, the setmar gene, derived from HsMar1, presents H3K4me3 modifications as expected for a human housekeeping gene. CONCLUSIONS Our work highlights that de novo and old HsMar1 are not similarly regulated by epigenetic mechanisms. Old HsMar1 are generally detected as lacking epigenetic marks, irrespective their localisation relative to the genes. Considering the putative existence of a network associating HsMar1 old copies and SETMAR, two non-mutually exclusive hypotheses are proposed: active and inactive HsMar1 copies are not similarly regulated or/and regulations concern only few loci (and few genes) that cannot be detected at the whole genome level.
Collapse
Affiliation(s)
- Sylvaine Renault
- EA 6306 Instabilité génétique et cancer, Université de Tours, UFR Sciences et Techniques, UFR Pharmacie, 31 Avenue Monge, 37200 Tours, France
- UMR 1253, iBrain, University of Tours, INSERM, Tours, France
| | - Murielle Genty
- EA 6306 Instabilité génétique et cancer, Université de Tours, UFR Sciences et Techniques, UFR Pharmacie, 31 Avenue Monge, 37200 Tours, France
- UMR 1253, iBrain, University of Tours, INSERM, Tours, France
| | - Alison Gabori
- EA 6306 Instabilité génétique et cancer, Université de Tours, UFR Sciences et Techniques, UFR Pharmacie, 31 Avenue Monge, 37200 Tours, France
| | - Catherine Boisneau
- UMR CITERES CNRS 7324, Université de Tours, 35 Allée Ferdinand de Lesseps, 37200 Tours, France
| | - Charles Esnault
- EA 6306 Instabilité génétique et cancer, Université de Tours, UFR Sciences et Techniques, UFR Pharmacie, 31 Avenue Monge, 37200 Tours, France
| | | | - Corinne Augé-Gouillou
- EA 6306 Instabilité génétique et cancer, Université de Tours, UFR Sciences et Techniques, UFR Pharmacie, 31 Avenue Monge, 37200 Tours, France
- UMR 1253, iBrain, University of Tours, INSERM, Tours, France
| |
Collapse
|
20
|
Palazzo A, Caizzi R, Viggiano L, Marsano RM. Does the Promoter Constitute a Barrier in the Horizontal Transposon Transfer Process? Insight from Bari Transposons. Genome Biol Evol 2018; 9:1637-1645. [PMID: 28854630 PMCID: PMC5570127 DOI: 10.1093/gbe/evx122] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2017] [Indexed: 12/11/2022] Open
Abstract
The contribution of the transposons’ promoter in the horizontal transfer process is quite overlooked in the scientific literature. To shed light on this aspect we have mimicked the horizontal transfer process in laboratory and assayed in a wide range of hosts (fly, human, yeast and bacteria) the promoter activity of the 5′ terminal sequences in Bari1 and Bari3, two Drosophila transposons belonging to the Tc1-mariner superfamily. These sequences are able to drive the transcription of a reporter gene even in distantly related organisms at least at the episomal level. By combining bioinformatics and experimental approaches, we define two distinct promoter sequences for each terminal sequence analyzed, which allow transcriptional activity in prokaryotes and eukaryotes, respectively. We propose that the Bari family of transposons, and possibly other members of the Tc1-mariner superfamily, might have evolved “blurry promoters,” which have facilitated their diffusion in many living organisms through horizontal transfer.
Collapse
Affiliation(s)
- Antonio Palazzo
- Department of Biology, University of Bari "Aldo Moro," Italy
| | - Ruggiero Caizzi
- Department of Biology, University of Bari "Aldo Moro," Italy
| | - Luigi Viggiano
- Department of Biology, University of Bari "Aldo Moro," Italy
| | | |
Collapse
|
21
|
Claeys Bouuaert C, Chalmers R. A single active site in the mariner transposase cleaves DNA strands of opposite polarity. Nucleic Acids Res 2017; 45:11467-11478. [PMID: 29036477 PMCID: PMC5714172 DOI: 10.1093/nar/gkx826] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 09/08/2017] [Indexed: 01/01/2023] Open
Abstract
The RNase H structural fold defines a large family of nucleic acid metabolizing enzymes that catalyze phosphoryl transfer reactions using two divalent metal ions in the active site. Almost all of these reactions involve only one strand of the nucleic acid substrates. In contrast, cut-and-paste transposases cleave two DNA strands of opposite polarity, which is usually achieved via an elegant hairpin mechanism. In the mariner transposons, the hairpin intermediate is absent and key aspects of the mechanism by which the transposon ends are cleaved remained unknown. Here, we characterize complexes involved prior to catalysis, which define an asymmetric pathway for transpososome assembly. Using mixtures of wild-type and catalytically inactive transposases, we show that all the catalytic steps of transposition occur within the context of a dimeric transpososome. Crucially, we find that each active site of a transposase dimer is responsible for two hydrolysis and one transesterification reaction at the same transposon end. These results provide the first strong evidence that a DDE/D active site can hydrolyze DNA strands of opposite polarity, a mechanism that has rarely been observed with any type of nuclease.
Collapse
Affiliation(s)
- Corentin Claeys Bouuaert
- School of Biomedical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Ronald Chalmers
- School of Biomedical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| |
Collapse
|
22
|
Kawakami K, Largaespada DA, Ivics Z. Transposons As Tools for Functional Genomics in Vertebrate Models. Trends Genet 2017; 33:784-801. [PMID: 28888423 DOI: 10.1016/j.tig.2017.07.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/14/2017] [Accepted: 07/18/2017] [Indexed: 02/06/2023]
Abstract
Genetic tools and mutagenesis strategies based on transposable elements are currently under development with a vision to link primary DNA sequence information to gene functions in vertebrate models. By virtue of their inherent capacity to insert into DNA, transposons can be developed into powerful tools for chromosomal manipulations. Transposon-based forward mutagenesis screens have numerous advantages including high throughput, easy identification of mutated alleles, and providing insight into genetic networks and pathways based on phenotypes. For example, the Sleeping Beauty transposon has become highly instrumental to induce tumors in experimental animals in a tissue-specific manner with the aim of uncovering the genetic basis of diverse cancers. Here, we describe a battery of mutagenic cassettes that can be applied in conjunction with transposon vectors to mutagenize genes, and highlight versatile experimental strategies for the generation of engineered chromosomes for loss-of-function as well as gain-of-function mutagenesis for functional gene annotation in vertebrate models, including zebrafish, mice, and rats.
Collapse
Affiliation(s)
- Koichi Kawakami
- Division of Molecular and Developmental Biology, National Institute of Genetics, Mishima, Japan; These authors contributed equally to this work
| | - David A Largaespada
- Department of Genetics, Cell Biology and Development, University of Minnesota, MN, USA; These authors contributed equally to this work
| | - Zoltán Ivics
- Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany; These authors contributed equally to this work..
| |
Collapse
|
23
|
Zhou MB, Hu H, Miskey C, Lazarow K, Ivics Z, Kunze R, Yang G, Izsvák Z, Tang DQ. Transposition of the bamboo Mariner-like element Ppmar1 in yeast. Mol Phylogenet Evol 2017; 109:367-374. [PMID: 28189615 DOI: 10.1016/j.ympev.2017.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 01/26/2017] [Accepted: 02/03/2017] [Indexed: 12/30/2022]
Abstract
The moso bamboo genome contains the two structurally intact and thus potentially functional mariner-like elements Ppmar1 and Ppmar2. Both elements contain perfect terminal inverted repeats (TIRs) and a full-length intact transposase gene. Here we investigated whether Ppmar1 is functional in yeast (Saccharomyces cerevisiae). We have designed a two-component system consisting of a transposase expression cassette and a non-autonomous transposon on two separate plasmids. We demonstrate that the Ppmar1 transposase Pptpase1 catalyses excision of the non-autonomous Ppmar1NA element from the plasmid and reintegration at TA dinucleotide sequences in the yeast chromosomes. In addition, we generated 14 hyperactive Ppmar1 transposase variants by systematic single amino acid substitutions. The most active transposase variant, S171A, induces 10-fold more frequent Ppmar1NA excisions in yeast than the wild type transposase. The Ppmar1 transposon is a promising tool for insertion mutagenesis in moso bamboo and may be used in other plants as an alternative to the established transposon tagging systems.
Collapse
Affiliation(s)
- Ming-Bing Zhou
- The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, LinAn, China
| | - Hui Hu
- The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, LinAn, China
| | - Csaba Miskey
- Paul Ehrlich Institute, Paul Ehrlich Str. 51-59, 63225 Langen, Germany
| | - Katina Lazarow
- Institute of Biology, Dahlem Centre of Plant Sciences, Freie Universität Berlin, 14195 Berlin, Germany
| | - Zoltán Ivics
- Paul Ehrlich Institute, Paul Ehrlich Str. 51-59, 63225 Langen, Germany
| | - Reinhard Kunze
- Institute of Biology, Dahlem Centre of Plant Sciences, Freie Universität Berlin, 14195 Berlin, Germany
| | - Guojun Yang
- Department of Biology, University of Toronto, Mississauga, ON, Canada
| | - Zsuzsanna Izsvák
- Max Delbrück Center for Molecular Medicine in the Helmholtz Society, Berlin, Germany.
| | - Ding-Qin Tang
- The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, LinAn, China.
| |
Collapse
|
24
|
Dussaussois-Montagne A, Jaillet J, Babin L, Verrelle P, Karayan-Tapon L, Renault S, Rousselot-Denis C, Zemmoura I, Augé-Gouillou C. SETMAR isoforms in glioblastoma: A matter of protein stability. Oncotarget 2017; 8:9835-9848. [PMID: 28038463 PMCID: PMC5354774 DOI: 10.18632/oncotarget.14218] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 12/05/2016] [Indexed: 01/10/2023] Open
Abstract
Glioblastomas (GBMs) are the most frequent and the most aggressive brain tumors, known for their chemo- and radio-resistance, making them often incurable. We also know that SETMAR is a protein involved in chromatin dynamics and genome plasticity, of which overexpression confers chemo- and radio-resistance to some tumors. The relationships between SETMAR and GBM have never been explored. To fill this gap, we define the SETMAR status of 44 resected tumors and of GBM derived cells, at both the mRNA and the protein levels. We identify a new, small SETMAR protein (so called SETMAR-1200), enriched in GBMs and GBM stem cells as compared to the regular enzyme (SETMAR-2100). We show that SETMAR-1200 is able to increase DNA repair by non-homologous end-joining, albeit with a lower efficiency than the regular SETMAR protein. Interestingly, the regular/small ratio of SETMAR in GBM cells changes depending on cell type, providing evidence that SETMAR expression is regulated by alternative splicing. We also demonstrate that SETMAR expression can be regulated by the use of an alternative ATG. In conclusion, various SETMAR proteins can be synthesized in human GBM that may each have specific biophysical and/or biochemical properties and characteristics. Among them, the small SETMAR may play a role in GBMs biogenesis. On this basis, we would like to consider SETMAR-1200 as a new potential therapeutic target to investigate, in addition to the regular SETMAR protein already considered by others.
Collapse
Affiliation(s)
| | - Jérôme Jaillet
- EA 6306 IGC, University François Rabelais, 37200 Tours, France
| | - Laetitia Babin
- EA 6306 IGC, University François Rabelais, 37200 Tours, France
- UMR CNRS 7292 GICC, University François Rabelais, 37000 Tours, France
| | - Pierre Verrelle
- EA 7283 CREaT, Université d′Auvergne, BP 10448, 63000 Clermont-Ferrand, France
- Institut Curie, Dpt d'Oncologie Radiothérapique, 75005 Paris, France
- Centre Jean Perrin, Service Radiothérapie, Laboratoire de Radio-Oncologie Expérimentale, 63000 Clermont-Ferrand, France
| | - Lucie Karayan-Tapon
- INSERM U1084, Laboratoire de Neurosciences Expérimentales et Cliniques, F-86021 Poitiers, France
- University of Poitiers, F-86022 Poitiers, France
- CHU of Poitiers, Laboratoire de Cancérologie Biologique, F-86021 Poitiers, France
| | | | | | - Ilyess Zemmoura
- INSERM U930 Imagerie & Cerveau, University François Rabelais, 37000 Tours, France
- CHRU of Tours, Service de Neurochirurgie, 37000 Tours, France
| | | |
Collapse
|
25
|
Wang Y, Pryputniewicz-Dobrinska D, Nagy EÉ, Kaufman CD, Singh M, Yant S, Wang J, Dalda A, Kay MA, Ivics Z, Izsvák Z. Regulated complex assembly safeguards the fidelity of Sleeping Beauty transposition. Nucleic Acids Res 2016; 45:311-326. [PMID: 27913727 PMCID: PMC5224488 DOI: 10.1093/nar/gkw1164] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 11/03/2016] [Accepted: 11/16/2016] [Indexed: 01/21/2023] Open
Abstract
The functional relevance of the inverted repeat structure (IR/DR) in a subgroup of the Tc1/mariner superfamily of transposons has been enigmatic. In contrast to mariner transposition, where a topological filter suppresses single-ended reactions, the IR/DR orchestrates a regulatory mechanism to enforce synapsis of the transposon ends before cleavage by the transposase occurs. This ordered assembly process shepherds primary transposase binding to the inner 12DRs (where cleavage does not occur), followed by capture of the 12DR of the other transposon end. This extra layer of regulation suppresses aberrant, potentially genotoxic recombination activities, and the mobilization of internally deleted copies in the IR/DR subgroup, including Sleeping Beauty (SB). In contrast, internally deleted sequences (MITEs) are preferred substrates of mariner transposition, and this process is associated with the emergence of Hsmar1-derived miRNA genes in the human genome. Translating IR/DR regulation to in vitro evolution yielded an SB transposon version with optimized substrate recognition (pT4). The ends of SB transposons excised by a K248A excision+/integration- transposase variant are processed by hairpin resolution, representing a link between phylogenetically, and mechanistically different recombination reactions, such as V(D)J recombination and transposition. Such variants generated by random mutation might stabilize transposon-host interactions or prepare the transposon for a horizontal transfer.
Collapse
Affiliation(s)
- Yongming Wang
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin 13125, Germany
| | | | - Enikö Éva Nagy
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin 13125, Germany
| | - Christopher D Kaufman
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin 13125, Germany
| | - Manvendra Singh
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin 13125, Germany
| | - Steve Yant
- Departments of Pediatrics and Genetics, Stanford University, Stanford, CA 94305-5164, USA
| | - Jichang Wang
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin 13125, Germany
| | - Anna Dalda
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin 13125, Germany
| | - Mark A Kay
- Departments of Pediatrics and Genetics, Stanford University, Stanford, CA 94305-5164, USA
| | - Zoltán Ivics
- Division of Medical Biotechnology, Paul-Ehrlich-Institute, Langen 63225, Germany
| | - Zsuzsanna Izsvák
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Society, Berlin 13125, Germany
| |
Collapse
|
26
|
Zhou M, Tao G, Pi P, Zhu Y, Bai Y, Meng X. Genome-wide characterization and evolution analysis of miniature inverted-repeat transposable elements (MITEs) in moso bamboo (Phyllostachys heterocycla). PLANTA 2016; 244:775-787. [PMID: 27160169 DOI: 10.1007/s00425-016-2544-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 05/01/2016] [Indexed: 06/05/2023]
Abstract
Moso bamboo MITEs were genome-wide identified first time, and data shows that MITEs contribute to the genomic diversity and differentiation of bamboo. Miniature inverted-repeat transposable elements (MITEs) are widespread in animals and plants. There are a large number of transposable elements in moso bamboo (Phyllostachys heterocycla var. pubescens) genome, but the genome-wide information of moso bamboo MITEs is not known yet. Here we identified 362 MITE families with a total of 489,592 MITE-related sequences, accounting for 4.74 % of the moso bamboo genome. The 362 MITE families are clustered into six known and one unknown super-families. Our analysis indicated that moso bamboo MITEs preferred to reside in or near the genes that might be involved in regulation of host gene expression. Of the seven super-families, three might undergo major expansion event twice, respectively, during 8-11 million years ago (mya) ago and 22-28 mya ago; two might experience a long expansion period from 6 to 13 mya. Almost 1/3 small RNAs might be derived from the MITE sequences. Some MITE families generate small RNAs mainly from the terminals, while others predominantly from the central region. Given the high copy number of MITEs, many siRNAs and miRNAs derived from MITE sequences and the preferential insertion of MITE into gene regions, MITEs may contribute to the genomic diversity and differentiation of bamboo.
Collapse
Affiliation(s)
- Mingbing Zhou
- The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, LinAn, 311300, Zhejiang Province, People's Republic of China.
| | - Guiyun Tao
- The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, LinAn, 311300, Zhejiang Province, People's Republic of China
| | - Peiyao Pi
- The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, LinAn, 311300, Zhejiang Province, People's Republic of China
| | - Yihang Zhu
- The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, LinAn, 311300, Zhejiang Province, People's Republic of China
| | - Youhuang Bai
- The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, LinAn, 311300, Zhejiang Province, People's Republic of China
| | - Xianwen Meng
- The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, LinAn, 311300, Zhejiang Province, People's Republic of China
| |
Collapse
|
27
|
Chen Q, Georgiadis M. Crystallization of and selenomethionine phasing strategy for a SETMAR-DNA complex. Acta Crystallogr F Struct Biol Commun 2016; 72:713-9. [PMID: 27599863 PMCID: PMC5012212 DOI: 10.1107/s2053230x16012723] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 08/06/2016] [Indexed: 11/10/2022] Open
Abstract
Transposable elements have played a critical role in the creation of new genes in all higher eukaryotes, including humans. Although the chimeric fusion protein SETMAR is no longer active as a transposase, it contains both the DNA-binding domain (DBD) and catalytic domain of the Hsmar1 transposase. The amino-acid sequence of the DBD has been virtually unchanged in 50 million years and, as a consequence, SETMAR retains its sequence-specific binding to the ancestral Hsmar1 terminal inverted repeat (TIR) sequence. Thus, the DNA-binding activity of SETMAR is likely to have an important biological function. To determine the structural basis for the recognition of TIR DNA by SETMAR, the design of TIR-containing oligonucleotides and SETMAR DBD variants, crystallization of DBD-DNA complexes, phasing strategies and initial phasing experiments are reported here. An unexpected finding was that oligonucleotides containing two BrdUs in place of thymidines produced better quality crystals in complex with SETMAR than their natural counterparts.
Collapse
Affiliation(s)
- Qiujia Chen
- Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA
| | - Millie Georgiadis
- Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA
| |
Collapse
|
28
|
Abstract
Sleeping Beauty (SB) is a synthetic transposon that was constructed based on sequences of transpositionally inactive elements isolated from fish genomes. SB is a Tc1/mariner superfamily transposon following a cut-and-paste transpositional reaction, during which the element-encoded transposase interacts with its binding sites in the terminal inverted repeats of the transposon, promotes the assembly of a synaptic complex, catalyzes excision of the element out of its donor site, and integrates the excised transposon into a new location in target DNA. SB transposition is dependent on cellular host factors. Transcriptional control of transposase expression is regulated by the HMG2L1 transcription factor. Synaptic complex assembly is promoted by the HMGB1 protein and regulated by chromatin structure. SB transposition is highly dependent on the nonhomologous end joining (NHEJ) pathway of double-strand DNA break repair that generates a transposon footprint at the excision site. Through its association with the Miz-1 transcription factor, the SB transposase downregulates cyclin D1 expression that results in a slowdown of the cell-cycle in the G1 phase, where NHEJ is preferentially active. Transposon integration occurs at TA dinucleotides in the target DNA, which are duplicated at the flanks of the integrated transposon. SB shows a random genome-wide insertion profile in mammalian cells when launched from episomal vectors and "local hopping" when launched from chromosomal donor sites. Some of the excised transposons undergo a self-destructive autointegration reaction, which can partially explain why longer elements transpose less efficiently. SB became an important molecular tool for transgenesis, insertional mutagenesis, and gene therapy.
Collapse
|
29
|
Abstract
The IS630-Tc1-mariner (ITm) family of transposons is one of the most widespread in nature. The phylogenetic distribution of its members shows that they do not persist for long in a given lineage, but rely on frequent horizontal transfer to new hosts. Although they are primarily selfish genomic-parasites, ITm transposons contribute to the evolution of their hosts because they generate variation and contribute protein domains and regulatory regions. Here we review the molecular mechanism of ITm transposition and its regulation. We focus mostly on the mariner elements, which are understood in the greatest detail owing to in vitro reconstitution and structural analysis. Nevertheless, the most important characteristics are probably shared across the grouping. Members of the ITm family are mobilized by a cut-and-paste mechanism and integrate at 5'-TA dinucleotide target sites. The elements encode a single transposase protein with an N-terminal DNA-binding domain and a C-terminal catalytic domain. The phosphoryl-transferase reactions during the DNA-strand breaking and joining reactions are performed by the two metal-ion mechanism. The metal ions are coordinated by three or four acidic amino acid residues located within an RNase H-like structural fold. Although all of the strand breaking and joining events at a given transposon end are performed by a single molecule of transposase, the reaction is coordinated by close communication between transpososome components. During transpososome assembly, transposase dimers compete for free transposon ends. This helps to protect the host by dampening an otherwise exponential increase in the rate of transposition as the copy number increases.
Collapse
|
30
|
Bire S, Casteret S, Piégu B, Beauclair L, Moiré N, Arensbuger P, Bigot Y. Mariner Transposons Contain a Silencer: Possible Role of the Polycomb Repressive Complex 2. PLoS Genet 2016; 12:e1005902. [PMID: 26939020 PMCID: PMC4777549 DOI: 10.1371/journal.pgen.1005902] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 02/05/2016] [Indexed: 12/31/2022] Open
Abstract
Transposable elements are driving forces for establishing genetic innovations such as transcriptional regulatory networks in eukaryotic genomes. Here, we describe a silencer situated in the last 300 bp of the Mos1 transposase open reading frame (ORF) which functions in vertebrate and arthropod cells. Functional silencers are also found at similar locations within three other animal mariner elements, i.e. IS630-Tc1-mariner (ITm) DD34D elements, Himar1, Hsmar1 and Mcmar1. These silencers are able to impact eukaryotic promoters monitoring strong, moderate or low expression as well as those of mariner elements located upstream of the transposase ORF. We report that the silencing involves at least two transcription factors (TFs) that are conserved within animal species, NFAT-5 and Alx1. These cooperatively act with YY1 to trigger the silencing activity. Four other housekeeping transcription factors (TFs), neuron restrictive silencer factor (NRSF), GAGA factor (GAF) and GTGT factor (GTF), were also found to have binding sites within mariner silencers but their impact in modulating the silencer activity remains to be further specified. Interestingly, an NRSF binding site was found to overlap a 30 bp motif coding a highly conserved PHxxYSPDLAPxD peptide in mariner transposases. We also present experimental evidence that silencing is mainly achieved by co-opting the host Polycomb Repressive Complex 2 pathway. However, we observe that when PRC2 is impaired another host silencing pathway potentially takes over to maintain weak silencer activity. Mariner silencers harbour features of Polycomb Response Elements, which are probably a way for mariner elements to self-repress their transcription and mobility in somatic and germinal cells when the required TFs are expressed. At the evolutionary scale, mariner elements, through their exaptation, might have been a source of silencers playing a role in the chromatin configuration in eukaryotic genomes. Transposons are mobile DNA sequences that have long co-evolved with the genome of their hosts. Consequently, they are involved in the generation of mutations, as well as the creation of genes and regulatory networks. Controlling the transposon activity, and consequently its negative effects on both the host soma and germ line, is a challenge for the survival of both the host and the transposon. To silence transposons, hosts often use defence mechanisms involving DNA methylation and RNA interference pathways. Here we show that mariner transposons can self-regulate their activity by using a silencer element located in their DNA sequence. The silencer element interferes with host housekeeping protein transcription factors involved in the polycomb silencing pathways. As the regulation of chromatin configuration by polycomb is an important regulator of animal development, our findings open the possibility that mariner silencers might have been exapted during animal evolution to participate in certain regulation pathways of their hosts. Since some of the TFs involved in mariner silencer activity play a role at different stages of nervous system development and neuron differentiation, it might be possible that mariner transposons can be active during some steps of cell differentiation. Interestingly, mariner transposons (i.e. IS630-Tc1-mariner (ITm) DD34D transposons) have so far only been found in genomes of animals having a nervous system.
Collapse
Affiliation(s)
- Solenne Bire
- PRC, UMR INRA-CNRS 7247, PRC, Nouzilly, France
- Institute of Biotechnology, University of Lausanne, and Center for Biotechnology UNIL-EPFL, Lausanne, Switzerland
| | | | | | | | | | - Peter Arensbuger
- Biological Sciences Department, California State Polytechnic University, Pomona, California, United States of America
| | - Yves Bigot
- PRC, UMR INRA-CNRS 7247, PRC, Nouzilly, France
- * E-mail:
| |
Collapse
|
31
|
Kim HS, Kim SK, Hromas R, Lee SH. The SET Domain Is Essential for Metnase Functions in Replication Restart and the 5' End of SS-Overhang Cleavage. PLoS One 2015; 10:e0139418. [PMID: 26437079 PMCID: PMC4593633 DOI: 10.1371/journal.pone.0139418] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 09/14/2015] [Indexed: 11/19/2022] Open
Abstract
Metnase (also known as SETMAR) is a chimeric SET-transposase protein that plays essential role(s) in non-homologous end joining (NHEJ) repair and replication fork restart. Although the SET domain possesses histone H3 lysine 36 dimethylation (H3K36me2) activity associated with an improved association of early repair components for NHEJ, its role in replication restart is less clear. Here we show that the SET domain is necessary for the recovery from DNA damage at the replication forks following hydroxyurea (HU) treatment. Cells overexpressing the SET deletion mutant caused a delay in fork restart after HU release. Our In vitro study revealed that the SET domain but not the H3K36me2 activity is required for the 5’ end of ss-overhang cleavage with fork and non-fork DNA without affecting the Metnase-DNA interaction. Together, our results suggest that the Metnase SET domain has a positive role in restart of replication fork and the 5’ end of ss-overhang cleavage, providing a new insight into the functional interaction of the SET and the transposase domains.
Collapse
Affiliation(s)
- Hyun-Suk Kim
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Sung-Kyung Kim
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Robert Hromas
- Department of Medicine, University of Florida and Shands Health Care System, Gainesville, Florida, United States of America
| | - Suk-Hee Lee
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- Indiana University Simon Cancer Center, Indianapolis, Indiana, United States of America
- * E-mail:
| |
Collapse
|
32
|
Sun C, Feschotte C, Wu Z, Mueller RL. DNA transposons have colonized the genome of the giant virus Pandoravirus salinus. BMC Biol 2015; 13:38. [PMID: 26067596 PMCID: PMC4495683 DOI: 10.1186/s12915-015-0145-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/03/2015] [Indexed: 01/06/2023] Open
Abstract
Background Transposable elements are mobile DNA sequences that are widely distributed in prokaryotic and eukaryotic genomes, where they represent a major force in genome evolution. However, transposable elements have rarely been documented in viruses, and their contribution to viral genome evolution remains largely unexplored. Pandoraviruses are recently described DNA viruses with genome sizes that exceed those of some prokaryotes, rivaling parasitic eukaryotes. These large genomes appear to include substantial noncoding intergenic spaces, which provide potential locations for transposable element insertions. However, no mobile genetic elements have yet been reported in pandoravirus genomes. Results Here, we report a family of miniature inverted-repeat transposable elements (MITEs) in the Pandoravirus salinus genome, representing the first description of a virus populated with a canonical transposable element family that proliferated by transposition within the viral genome. The MITE family, which we name Submariner, includes 30 copies with all the hallmarks of MITEs: short length, terminal inverted repeats, TA target site duplication, and no coding capacity. Submariner elements show signs of transposition and are undetectable in the genome of Pandoravirus dulcis, the closest known relative Pandoravirus salinus. We identified a DNA transposon related to Submariner in the genome of Acanthamoeba castellanii, a species thought to host pandoraviruses, which contains remnants of coding sequence for a Tc1/mariner transposase. These observations suggest that the Submariner MITEs of P. salinus belong to the widespread Tc1/mariner superfamily and may have been mobilized by an amoebozoan host. Ten of the 30 MITEs in the P. salinus genome are located within coding regions of predicted genes, while others are close to genes, suggesting that these transposons may have contributed to viral genetic novelty. Conclusions Our discovery highlights the remarkable ability of DNA transposons to colonize and shape genomes from all domains of life, as well as giant viruses. Our findings continue to blur the division between viral and cellular genomes, adhering to the emerging view that the content, dynamics, and evolution of the genomes of giant viruses do not substantially differ from those of cellular organisms. Electronic supplementary material The online version of this article (doi:10.1186/s12915-015-0145-1) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Cheng Sun
- Department of Biology, Colorado State University, Campus Delivery 1878, Fort Collins, CO, 80523-1878, USA.
| | - Cédric Feschotte
- Department of Human Genetics, The University of Utah, Salt Lake City, UT, 84112, USA.
| | - Zhiqiang Wu
- Department of Biology, Colorado State University, Campus Delivery 1878, Fort Collins, CO, 80523-1878, USA.
| | - Rachel Lockridge Mueller
- Department of Biology, Colorado State University, Campus Delivery 1878, Fort Collins, CO, 80523-1878, USA.
| |
Collapse
|
33
|
Identification, Diversity and Evolution of MITEs in the Genomes of Microsporidian Nosema Parasites. PLoS One 2015; 10:e0123170. [PMID: 25898273 PMCID: PMC4405373 DOI: 10.1371/journal.pone.0123170] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 01/27/2015] [Indexed: 11/29/2022] Open
Abstract
Miniature inverted-repeat transposable elements (MITEs) are short, non-autonomous DNA transposons, which are widespread in most eukaryotic genomes. However, genome-wide identification, origin and evolution of MITEs remain largely obscure in microsporidia. In this study, we investigated structural features for de novo identification of MITEs in genomes of silkworm microsporidia Nosema bombycis and Nosema antheraeae, as well as a honeybee microsporidia Nosema ceranae. A total of 1490, 149 and 83 MITE-related sequences from 89, 17 and five families, respectively, were found in the genomes of the above-mentioned species. Species-specific MITEs are predominant in each genome of microsporidian Nosema, with the exception of three MITE families that were shared by N. bombycis and N. antheraeae. One or multiple rounds of amplification occurred for MITEs in N. bombycis after divergence between N. bombycis and the other two species, suggesting that the more abundant families in N. bombycis could be attributed to the recent amplification of new MITEs. Significantly, some MITEs that inserted into the homologous protein-coding region of N. bombycis were recruited as introns, indicating that gene expansion occurred during the evolution of microsporidia. NbS31 and NbS24 had polymorphisms in different geographical strains of N. bombycis, indicating that they could still be active. In addition, several small RNAs in the MITEs in N. bombycis are mainly produced from both ends of the MITEs sequence.
Collapse
|
34
|
Fattash I, Lee CN, Mo K, Yang G. Efficient transposition of the youngest miniature inverted repeat transposable element family of yellow fever mosquito in yeast. FEBS J 2015; 282:1829-40. [PMID: 25754725 DOI: 10.1111/febs.13257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 02/13/2015] [Accepted: 03/04/2015] [Indexed: 01/16/2023]
Abstract
Miniature inverted repeat transposable elements (MITEs) are often the most numerous DNA transposons in plant and animal genomes. The dramatic amplification of MITE families during evolution is puzzling, because the transposase sources for the vast majority of MITE families are unknown. The yellow fever mosquito genome contains > 220-Mb MITE sequences; however, transposition activity has not been demonstrated for any of the MITE families. The Gnome elements are the youngest MITE family in this genome, with at least 116 identical copies. To test whether the putative autonomous element Ozma is capable of mobilizing Gnome and its two sibling MITEs, analyses were performed in a yeast transposition assay system. Whereas the wild-type transposase resulted in very low transposition activity, mutations in the region containing a putative nuclear export signal motif resulted in a dramatic (at least 4160-fold) increase in transposition frequency. We have also demonstrated that each residue of the novel DD37E motif is required for the activity of the Ozma transposase. Footprint sequences left at the donor sites suggest that the transposase may cleave between the second and the third nucleotides from the 5' ends of the elements. The excised elements reinsert specifically at dinucleotide 'TA', ~ 55% of them in yeast genes. The elements described in this article could potentially be useful as genetic tools for genetic manipulation of mosquitoes.
Collapse
Affiliation(s)
- Isam Fattash
- Department of Biology, University of Toronto Mississauga, ON, Canada
| | - Chia-Ni Lee
- Department of Biology, University of Toronto Mississauga, ON, Canada
| | - Kaiguo Mo
- Department of Biology, University of Toronto Mississauga, ON, Canada
| | - Guojun Yang
- Department of Biology, University of Toronto Mississauga, ON, Canada
| |
Collapse
|
35
|
Damasceno JD, Beverley SM, Tosi LRO. A transposon-based tool for transformation and mutagenesis in trypanosomatid protozoa. Methods Mol Biol 2015; 1201:235-245. [PMID: 25388118 PMCID: PMC4287265 DOI: 10.1007/978-1-4939-1438-8_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The ability of transposable elements to mobilize across genomes and affect the expression of genes makes them exceptional tools for genetic manipulation methodologies. Several transposon-based systems have been modified and incorporated into shuttle mutagenesis approaches in a variety of organisms. We have found that the Mos1 element, a DNA transposon from Drosophila mauritiana, is suitable and readily adaptable to a variety of strategies to the study of trypanosomatid parasitic protozoa. Trypanosomatids are the causative agents of a wide range of neglected diseases in underdeveloped regions of the globe. In this chapter we describe the basic elements and the available protocols for the in vitro use of Mos1 derivatives in the protozoan parasite Leishmania.
Collapse
Affiliation(s)
- Jeziel D Damasceno
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av Bandeirantes, 3900, Ribeirão Preto, SP, 14049-900, Brazil
| | | | | |
Collapse
|
36
|
Wallau GL, Capy P, Loreto E, Hua-Van A. Genomic landscape and evolutionary dynamics of mariner transposable elements within the Drosophila genus. BMC Genomics 2014; 15:727. [PMID: 25163909 PMCID: PMC4161770 DOI: 10.1186/1471-2164-15-727] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 08/01/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The mariner family of transposable elements is one of the most widespread in the Metazoa. It is subdivided into several subfamilies that do not mirror the phylogeny of these species, suggesting an ancient diversification. Previous hybridization and PCR studies allowed a partial survey of mariner diversity in the Metazoa. In this work, we used a comparative genomics approach to access the genus-wide diversity and evolution of mariner transposable elements in twenty Drosophila sequenced genomes. RESULTS We identified 36 different mariner lineages belonging to six distinct subfamilies, including a subfamily not described previously. Wide variation in lineage abundance and copy number were observed among species and among mariner lineages, suggesting continuous turn-over. Most mariner lineages are inactive and contain a high proportion of damaged copies. We showed that, in addition to substitutions that rapidly inactivate copies, internal deletion is a major mechanism contributing to element decay and the generation of non-autonomous sublineages. Hence, 23% of copies correspond to several Miniature Inverted-repeat Transposable Elements (MITE) sublineages, the first ever described in Drosophila for mariner. In the most successful MITEs, internal deletion is often associated with internal rearrangement, which sheds light on the process of MITE origin. The estimation of the transposition rates over time revealed that all lineages followed a similar progression consisting of a rapid amplification burst followed by a rapid decrease in transposition. We detected some instances of multiple or ongoing transposition bursts. Different amplification times were observed for mariner lineages shared by different species, a finding best explained by either horizontal transmission or a reactivation process. Different lineages within one species have also amplified at different times, corresponding to successive invasions. Finally, we detected a preference for insertion into short TA-rich regions, which appears to be specific to some subfamilies. CONCLUSIONS This analysis is the first comprehensive survey of this family of transposable elements at a genus scale. It provides precise measures of the different evolutionary processes that were hypothesized previously for this family based on PCR data analysis. mariner lineages were observed at almost all "life cycle" stages: recent amplification, subsequent decay and potential (re)-invasion or invasion of genomes.
Collapse
Affiliation(s)
- Gabriel Luz Wallau
- Pós-Graduaíão em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, Brasil.
| | | | | | | |
Collapse
|
37
|
Claeys Bouuaert C, Walker N, Liu D, Chalmers R. Crosstalk between transposase subunits during cleavage of the mariner transposon. Nucleic Acids Res 2014; 42:5799-808. [PMID: 24623810 PMCID: PMC4027188 DOI: 10.1093/nar/gku172] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 02/10/2014] [Accepted: 02/11/2014] [Indexed: 12/18/2022] Open
Abstract
Mariner transposition is a complex reaction that involves three recombination sites and six strand breaking and joining reactions. This requires precise spatial and temporal coordination between the different components to ensure a productive outcome and minimize genomic instability. We have investigated how the cleavage events are orchestrated within the mariner transpososome. We find that cleavage of the non-transferred strand is completed at both transposon ends before the transferred strand is cleaved at either end. By introducing transposon-end mutations that interfere with cleavage, but leave transpososome assembly unaffected, we demonstrate that a structural transition preceding transferred strand cleavage is coordinated between the two halves of the transpososome. Since mariner lacks the DNA hairpin intermediate, this transition probably reflects a reorganization of the transpososome to allow the access of different monomers onto the second pair of strands, or the relocation of the DNA within the same active site between two successive hydrolysis events. Communication between transposase subunits also provides a failsafe mechanism that restricts the generation of potentially deleterious double-strand breaks at isolated sites. Finally, we identify transposase mutants that reveal that the conserved WVPHEL motif provides a structural determinant of the coordination mechanism.
Collapse
Affiliation(s)
- Corentin Claeys Bouuaert
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Neil Walker
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Danxu Liu
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Ronald Chalmers
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| |
Collapse
|
38
|
Campos-Sánchez R, Kapusta A, Feschotte C, Chiaromonte F, Makova KD. Genomic landscape of human, bat, and ex vivo DNA transposon integrations. Mol Biol Evol 2014; 31:1816-32. [PMID: 24809961 DOI: 10.1093/molbev/msu138] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The integration and fixation preferences of DNA transposons, one of the major classes of eukaryotic transposable elements, have never been evaluated comprehensively on a genome-wide scale. Here, we present a detailed study of the distribution of DNA transposons in the human and bat genomes. We studied three groups of DNA transposons that integrated at different evolutionary times: 1) ancient (>40 My) and currently inactive human elements, 2) younger (<40 My) bat elements, and 3) ex vivo integrations of piggyBat and Sleeping Beauty elements in HeLa cells. Although the distribution of ex vivo elements reflected integration preferences, the distribution of human and (to a lesser extent) bat elements was also affected by selection. We used regression techniques (linear, negative binomial, and logistic regression models with multiple predictors) applied to 20-kb and 1-Mb windows to investigate how the genomic landscape in the vicinity of DNA transposons contributes to their integration and fixation. Our models indicate that genomic landscape explains 16-79% of variability in DNA transposon genome-wide distribution. Importantly, we not only confirmed previously identified predictors (e.g., DNA conformation and recombination hotspots) but also identified several novel predictors (e.g., signatures of double-strand breaks and telomere hexamer). Ex vivo integrations showed a bias toward actively transcribed regions. Older DNA transposons were located in genomic regions scarce in most conserved elements-likely reflecting purifying selection. Our study highlights how DNA transposons are integral to the evolution of bat and human genomes, and has implications for the development of DNA transposon assays for gene therapy and mutagenesis applications.
Collapse
Affiliation(s)
- Rebeca Campos-Sánchez
- Genetics Program, The Huck Institutes of the Life Sciences, Penn State University, University Park, PA
| | - Aurélie Kapusta
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT
| | - Cédric Feschotte
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT
| | - Francesca Chiaromonte
- Center for Medical Genomics, The Huck Institutes of the Life Sciences, Penn State University, University Park, PADepartment of Statistics, Penn State University, University Park, PA
| | - Kateryna D Makova
- Center for Medical Genomics, The Huck Institutes of the Life Sciences, Penn State University, University Park, PADepartment of Biology, Penn State University, University Park, PA
| |
Collapse
|
39
|
Kim HS, Chen Q, Kim SK, Nickoloff JA, Hromas R, Georgiadis MM, Lee SH. The DDN catalytic motif is required for Metnase functions in non-homologous end joining (NHEJ) repair and replication restart. J Biol Chem 2014; 289:10930-10938. [PMID: 24573677 PMCID: PMC4036204 DOI: 10.1074/jbc.m113.533216] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Metnase (or SETMAR) arose from a chimeric fusion of the Hsmar1 transposase downstream of a protein methylase in anthropoid primates. Although the Metnase transposase domain has been largely conserved, its catalytic motif (DDN) differs from the DDD motif of related transposases, which may be important for its role as a DNA repair factor and its enzymatic activities. Here, we show that substitution of DDN610 with either DDD610 or DDE610 significantly reduced in vivo functions of Metnase in NHEJ repair and accelerated restart of replication forks. We next tested whether the DDD or DDE mutants cleave single-strand extensions and flaps in partial duplex DNA and pseudo-Tyr structures that mimic stalled replication forks. Neither substrate is cleaved by the DDD or DDE mutant, under the conditions where wild-type Metnase effectively cleaves ssDNA overhangs. We then characterized the ssDNA-binding activity of the Metnase transposase domain and found that the catalytic domain binds ssDNA but not dsDNA, whereas dsDNA binding activity resides in the helix-turn-helix DNA binding domain. Substitution of Asn-610 with either Asp or Glu within the transposase domain significantly reduces ssDNA binding activity. Collectively, our results suggest that a single mutation DDN610 → DDD610, which restores the ancestral catalytic site, results in loss of function in Metnase.
Collapse
Affiliation(s)
- Hyun-Suk Kim
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Qiujia Chen
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Sung-Kyung Kim
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523
| | - Robert Hromas
- Department of Medicine, University of Florida and Shands Health Care System, Gainesville, Florida 32610
| | - Millie M Georgiadis
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Chemistry and Chemical Biology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana 46202
| | - Suk-Hee Lee
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202.
| |
Collapse
|
40
|
Trubitsyna M, Morris ER, Finnegan DJ, Richardson JM. Biochemical characterization and comparison of two closely related active mariner transposases. Biochemistry 2014; 53:682-9. [PMID: 24404958 PMCID: PMC3922039 DOI: 10.1021/bi401193w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
![]()
Most DNA transposons move from one
genomic location to another
by a cut-and-paste mechanism and are useful tools for genomic manipulations.
Short inverted repeat (IR) DNA sequences marking each end of the transposon
are recognized by a DNA transposase (encoded by the transposon itself).
This enzyme cleaves the transposon ends and integrates them at a new
genomic location. We report here a comparison of the biophysical and
biochemical properties of two closely related and active mariner/Tc1 family DNA transposases: Mboumar-9 and Mos1. We compared the in vitro cleavage activities of the enzymes on their own
IR sequences, as well as cross-recognition of their inverted repeat
sequences. We found that, like Mos1, untagged recombinant Mboumar-9
transposase is a dimer and forms a stable complex with inverted repeat
DNA in the presence of Mg2+ ions. Mboumar-9 transposase
cleaves its inverted repeat DNA in the manner observed for Mos1 transposase.
There was minimal cross-recognition of IR sequences between Mos1 and
Mboumar-9 transposases, despite these enzymes having 68% identical
amino acid sequences. Transposases sharing common biophysical and
biochemical properties, but retaining recognition specificity toward
their own IR, are a promising platform for the design of chimeric
transposases with predicted and improved sequence recognition.
Collapse
Affiliation(s)
- Maryia Trubitsyna
- School of Biological Sciences, University of Edinburgh , The King's Buildings, Mayfield Road, Edinburgh EH9 3JR, United Kingdom
| | | | | | | |
Collapse
|
41
|
Bouchet N, Jaillet J, Gabant G, Brillet B, Briseño-Roa L, Cadene M, Augé-Gouillou C. cAMP protein kinase phosphorylates the Mos1 transposase and regulates its activity: evidences from mass spectrometry and biochemical analyses. Nucleic Acids Res 2014; 42:1117-28. [PMID: 24081583 PMCID: PMC3902898 DOI: 10.1093/nar/gkt874] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/05/2013] [Accepted: 09/06/2013] [Indexed: 12/19/2022] Open
Abstract
Genomic plasticity mediated by transposable elements can have a dramatic impact on genome integrity. To minimize its genotoxic effects, it is tightly regulated either by intrinsic mechanisms (linked to the element itself) or by host-mediated mechanisms. Using mass spectrometry, we show here for the first time that MOS1, the transposase driving the mobility of the mariner Mos1 element, is phosphorylated. We also show that the transposition activity of MOS1 is downregulated by protein kinase AMP cyclic-dependent phosphorylation at S170, which renders the transposase unable to promote Mos1 transposition. One step in the transposition cycle, the assembly of the paired-end complex, is specifically inhibited. At the cellular level, we provide evidence that phosphorylation at S170 prevents the active transport of the transposase into the nucleus. Our data suggest that protein kinase AMP cyclic-dependent phosphorylation may play a double role in the early stages of genome invasion by mariner elements.
Collapse
Affiliation(s)
- Nicolas Bouchet
- Innovation Moléculaire Thérapeutique, EA 6306, UFR Sciences Pharmaceutiques, Parc Grandmont, Université François Rabelais, 37200 Tours, France, Centre de Biophysique Moléculaire, UPR 4301 CNRS, Rue Charles Sadron, 45071 Orléans, France, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IUT de Quimper, Université de Bretagne Occidentale, 6 rue de l’Université, 29000 Quimper, France and Biologie Cellulaire de la Synapse, INSERM U789, Ecole Normale Supérieure, 46 rue d'Ulm, 75005 Paris, France
| | - Jérôme Jaillet
- Innovation Moléculaire Thérapeutique, EA 6306, UFR Sciences Pharmaceutiques, Parc Grandmont, Université François Rabelais, 37200 Tours, France, Centre de Biophysique Moléculaire, UPR 4301 CNRS, Rue Charles Sadron, 45071 Orléans, France, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IUT de Quimper, Université de Bretagne Occidentale, 6 rue de l’Université, 29000 Quimper, France and Biologie Cellulaire de la Synapse, INSERM U789, Ecole Normale Supérieure, 46 rue d'Ulm, 75005 Paris, France
| | - Guillaume Gabant
- Innovation Moléculaire Thérapeutique, EA 6306, UFR Sciences Pharmaceutiques, Parc Grandmont, Université François Rabelais, 37200 Tours, France, Centre de Biophysique Moléculaire, UPR 4301 CNRS, Rue Charles Sadron, 45071 Orléans, France, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IUT de Quimper, Université de Bretagne Occidentale, 6 rue de l’Université, 29000 Quimper, France and Biologie Cellulaire de la Synapse, INSERM U789, Ecole Normale Supérieure, 46 rue d'Ulm, 75005 Paris, France
| | - Benjamin Brillet
- Innovation Moléculaire Thérapeutique, EA 6306, UFR Sciences Pharmaceutiques, Parc Grandmont, Université François Rabelais, 37200 Tours, France, Centre de Biophysique Moléculaire, UPR 4301 CNRS, Rue Charles Sadron, 45071 Orléans, France, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IUT de Quimper, Université de Bretagne Occidentale, 6 rue de l’Université, 29000 Quimper, France and Biologie Cellulaire de la Synapse, INSERM U789, Ecole Normale Supérieure, 46 rue d'Ulm, 75005 Paris, France
| | - Luis Briseño-Roa
- Innovation Moléculaire Thérapeutique, EA 6306, UFR Sciences Pharmaceutiques, Parc Grandmont, Université François Rabelais, 37200 Tours, France, Centre de Biophysique Moléculaire, UPR 4301 CNRS, Rue Charles Sadron, 45071 Orléans, France, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IUT de Quimper, Université de Bretagne Occidentale, 6 rue de l’Université, 29000 Quimper, France and Biologie Cellulaire de la Synapse, INSERM U789, Ecole Normale Supérieure, 46 rue d'Ulm, 75005 Paris, France
| | - Martine Cadene
- Innovation Moléculaire Thérapeutique, EA 6306, UFR Sciences Pharmaceutiques, Parc Grandmont, Université François Rabelais, 37200 Tours, France, Centre de Biophysique Moléculaire, UPR 4301 CNRS, Rue Charles Sadron, 45071 Orléans, France, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IUT de Quimper, Université de Bretagne Occidentale, 6 rue de l’Université, 29000 Quimper, France and Biologie Cellulaire de la Synapse, INSERM U789, Ecole Normale Supérieure, 46 rue d'Ulm, 75005 Paris, France
| | - Corinne Augé-Gouillou
- Innovation Moléculaire Thérapeutique, EA 6306, UFR Sciences Pharmaceutiques, Parc Grandmont, Université François Rabelais, 37200 Tours, France, Centre de Biophysique Moléculaire, UPR 4301 CNRS, Rue Charles Sadron, 45071 Orléans, France, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IUT de Quimper, Université de Bretagne Occidentale, 6 rue de l’Université, 29000 Quimper, France and Biologie Cellulaire de la Synapse, INSERM U789, Ecole Normale Supérieure, 46 rue d'Ulm, 75005 Paris, France
| |
Collapse
|
42
|
Skipper KA, Andersen PR, Sharma N, Mikkelsen JG. DNA transposon-based gene vehicles - scenes from an evolutionary drive. J Biomed Sci 2013; 20:92. [PMID: 24320156 PMCID: PMC3878927 DOI: 10.1186/1423-0127-20-92] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 11/27/2013] [Indexed: 12/12/2022] Open
Abstract
DNA transposons are primitive genetic elements which have colonized living organisms from plants to bacteria and mammals. Through evolution such parasitic elements have shaped their host genomes by replicating and relocating between chromosomal loci in processes catalyzed by the transposase proteins encoded by the elements themselves. DNA transposable elements are constantly adapting to life in the genome, and self-suppressive regulation as well as defensive host mechanisms may assist in buffering ‘cut-and-paste’ DNA mobilization until accumulating mutations will eventually restrict events of transposition. With the reconstructed Sleeping Beauty DNA transposon as a powerful engine, a growing list of transposable elements with activity in human cells have moved into biomedical experimentation and preclinical therapy as versatile vehicles for delivery and genomic insertion of transgenes. In this review, we aim to link the mechanisms that drive transposon evolution with the realities and potential challenges we are facing when adapting DNA transposons for gene transfer. We argue that DNA transposon-derived vectors may carry inherent, and potentially limiting, traits of their mother elements. By understanding in detail the evolutionary journey of transposons, from host colonization to element multiplication and inactivation, we may better exploit the potential of distinct transposable elements. Hence, parallel efforts to investigate and develop distinct, but potent, transposon-based vector systems will benefit the broad applications of gene transfer. Insight and clever optimization have shaped new DNA transposon vectors, which recently debuted in the first DNA transposon-based clinical trial. Learning from an evolutionary drive may help us create gene vehicles that are safer, more efficient, and less prone for suppression and inactivation.
Collapse
Affiliation(s)
| | | | | | - Jacob Giehm Mikkelsen
- Department of Biomedicine, Aarhus University, Wilh, Meyers Allé 4, DK-8000, Aarhus C, Denmark.
| |
Collapse
|
43
|
Pflieger A, Jaillet J, Petit A, Augé-Gouillou C, Renault S. Target capture during Mos1 transposition. J Biol Chem 2013; 289:100-11. [PMID: 24269942 DOI: 10.1074/jbc.m113.523894] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
DNA transposition contributes to genomic plasticity. Target capture is a key step in the transposition process, because it contributes to the selection of new insertion sites. Nothing or little is known about how eukaryotic mariner DNA transposons trigger this step. In the case of Mos1, biochemistry and crystallography have deciphered several inverted terminal repeat-transposase complexes that are intermediates during transposition. However, the target capture complex is still unknown. Here, we show that the preintegration complex (i.e., the excised transposon) is the only complex able to capture a target DNA. Mos1 transposase does not support target commitment, which has been proposed to explain Mos1 random genomic integrations within host genomes. We demonstrate that the TA dinucleotide used as the target is crucial both to target recognition and in the chemistry of the strand transfer reaction. Bent DNA molecules are better targets for the capture when the target DNA is nicked two nucleotides apart from the TA. They improve strand transfer when the target DNA contains a mismatch near the TA dinucleotide.
Collapse
Affiliation(s)
- Aude Pflieger
- From the EA 6306 Innovation Moléculaire et Thérapeutique, Université François Rabelais, UFR des Sciences et Techniques, UFR de Pharmacie, 37200 Tours, France
| | | | | | | | | |
Collapse
|
44
|
Gil E, Bosch A, Lampe D, Lizcano JM, Perales JC, Danos O, Chillon M. Functional characterization of the human mariner transposon Hsmar2. PLoS One 2013; 8:e73227. [PMID: 24039890 PMCID: PMC3770610 DOI: 10.1371/journal.pone.0073227] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 07/19/2013] [Indexed: 12/23/2022] Open
Abstract
DNA transposons are mobile elements with the ability to mobilize and transport genetic information between different chromosomal loci. Unfortunately, most transposons copies are currently inactivated, little is known about mariner elements in humans despite their role in the evolution of the human genome, even though the Hsmar2 transposon is associated to hotspots for homologous recombination involved in human genetic disorders as Charcot–Marie–Tooth, Prader-Willi/Angelman, and Williams syndromes. This manuscript describes the functional characterization of the human HSMAR2 transposase generated from fossil sequences and shows that the native HSMAR2 is active in human cells, but also in bacteria, with an efficiency similar to other mariner elements. We observe that the sub-cellular localization of HSMAR2 is dependent on the host cell type, and is cytotoxic when overexpressed in HeLa cells. Finally, we also demonstrate that the binding of HSMAR2 to its own ITRs is specific, and that the excision reaction leaves non-canonical footprints both in bacteria and eukaryotic cells.
Collapse
Affiliation(s)
- Estel Gil
- Department of Biochemistry and Molecular Biology, Edifici H, Center of Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Assumpcio Bosch
- Department of Biochemistry and Molecular Biology, Edifici H, Center of Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - David Lampe
- Department of Biological Sciences, Bayer School of Natural and Environmental Sciences, Duquesne University, Pittsburgh, Pennsylvania, United States of America
| | - Jose M. Lizcano
- Department of Biochemistry and Molecular Biology, Institut de Neurociences, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Jose C. Perales
- Department of Physiological Sciences II, IDIBELL, University of Barcelona, Campus de Bellvitge, L’Hospitalet de Llobregat, Barcelona, Spain
| | - Olivier Danos
- Institut National de la Sante et de la recherche Medicale U845, Hôpital Necker Enfants Malades, Université Paris Descartes, Paris, France
| | - Miguel Chillon
- Department of Biochemistry and Molecular Biology, Edifici H, Center of Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona, Bellaterra, Spain
- Institut Català de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
- * E-mail:
| |
Collapse
|
45
|
Abstract
DNA transposases are enzymes that catalyze the movement of discrete pieces of DNA from one location in the genome to another. Transposition occurs through a series of controlled DNA strand cleavage and subsequent integration reactions that are carried out by nucleoprotein complexes known as transpososomes. Transpososomes are dynamic assemblies which must undergo conformational changes that control DNA breaks and ensure that, once started, the transposition reaction goes to completion. They provide a precise architecture within which the chemical reactions involved in transposon movement occur, but adopt different conformational states as transposition progresses. Their components also vary as they must, at some stage, include target DNA and sometimes even host-encoded proteins. A very limited number of transpososome states have been crystallographically captured, and here we provide an overview of the various structures determined to date. These structures include examples of DNA transposases that catalyze transposition by a cut-and-paste mechanism using an RNaseH-like nuclease catalytic domain, those that transpose using only single-stranded DNA substrates and targets, and the retroviral integrases that carry out an integration reaction very similar to DNA transposition. Given that there are a number of common functional requirements for transposition, it is remarkable how these are satisfied by complex assemblies that are so architecturally different.
Collapse
|
46
|
Claeys Bouuaert C, Lipkow K, Andrews SS, Liu D, Chalmers R. The autoregulation of a eukaryotic DNA transposon. eLife 2013; 2:e00668. [PMID: 23795293 PMCID: PMC3687335 DOI: 10.7554/elife.00668] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 05/13/2013] [Indexed: 01/03/2023] Open
Abstract
How do DNA transposons live in harmony with their hosts? Bacteria provide the only documented mechanisms for autoregulation, but these are incompatible with eukaryotic cell biology. Here we show that autoregulation of Hsmar1 operates during assembly of the transpososome and arises from the multimeric state of the transposase, mediated by a competition for binding sites. We explore the dynamics of a genomic invasion using a computer model, supported by in vitro and in vivo experiments, and show that amplification accelerates at first but then achieves a constant rate. The rate is proportional to the genome size and inversely proportional to transposase expression and its affinity for the transposon ends. Mariner transposons may therefore resist post-transcriptional silencing. Because regulation is an emergent property of the reaction it is resistant to selfish exploitation. The behavior of distantly related eukaryotic transposons is consistent with the same mechanism, which may therefore be widely applicable. DOI:http://dx.doi.org/10.7554/eLife.00668.001 Transposons are regions of mobile DNA that can jump from one location in the genome to another. This represents a genetic burden to the host because there is always the risk that the transposon will inactivate a cellular gene. However, a greater problem is that transposition is accompanied by an increase in the number of copies of the transposon. Since each new copy will be a source of further new copies, amplification of transposons is necessarily exponential. The fact that eukaryotic cells are able to tolerate DNA transposons suggests the existence of regulatory mechanisms to defuse the inevitable genomic melt-down. Host-mediated epigenetic modifications and RNA interference will provide some level of protection. However, they are by no means completely effective and a well-adapted genomic parasite, such as a transposon, might be expected to have its own mechanism of regulation. Now, Claeys Bouuaert, Lipkow and colleagues have used a computer model in combination with in vivo and in vitro experiments to search for this mechanism. Their experiments reveal how a DNA transposon is down-regulated by its own transposase. The transposase is the enzyme that catalyzes the ‘jump’ or transposition. It binds to specific sites at either end of the transposon and brings these together to make up a nucleoprotein complex called the transpososome. It is within this complex that the chemical steps of the reaction take place. When the number of transposons increases, so does the concentration of transposase. Claeys Bouuaert et al. show that the binding sites become saturated at a relatively low transposase concentration and that negative regulation arises from the resulting competition. Thus, the rate of transposition decreases as the number of transposons increases. They further use the computer model to explore how the amplification of the transposon is affected by transposon-specific and cellular-specific factors. Claeys Bouuaert, Lipkow and colleagues based their study predominantly on a resurrected copy of the Hsmar1 transposon, which was active in the human genome 50 million years ago. However, they also tested two distantly related eukaryotic transposons and observed that their behavior was similar, which suggests that this could be a general mechanism that controls the activity of jumping genes. They also note that their competition mechanism is conceptually similar to the immunological ‘prozone effect’. This is a recurrent theme in protein chemistry and demonstrates once again that less is in fact sometimes more. DOI:http://dx.doi.org/10.7554/eLife.00668.002
Collapse
|
47
|
Fattash I, Bhardwaj P, Hui C, Yang G. A rice Stowaway MITE for gene transfer in yeast. PLoS One 2013; 8:e64135. [PMID: 23704977 PMCID: PMC3660474 DOI: 10.1371/journal.pone.0064135] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 04/11/2013] [Indexed: 02/06/2023] Open
Abstract
Miniature inverted repeat transposable elements (MITEs) lack protein coding capacity and often share very limited sequence similarity with potential autonomous elements. Their capability of efficient transposition and dramatic amplification led to the proposition that MITEs are an untapped rich source of materials for transposable element (TE) based genetic tools. To test the concept of using MITE sequence in gene transfer, a rice Stowaway MITE previously shown to excise efficiently in yeast was engineered to carry cargo genes (neo and gfp) for delivery into the budding yeast genome. Efficient excision of the cargo gene cassettes was observed even though the excision frequency generally decreases with the increase of the cargo sizes. Excised elements insert into new genomic loci efficiently, with about 65% of the obtained insertion sites located in genes. Elements at the primary insertion sites can be remobilized, frequently resulting in copy number increase of the element. Surprisingly, the orientation of a cargo gene (neo) on a construct bearing dual reporter genes (gfp and neo) was found to have a dramatic effect on transposition frequency. These results demonstrated the concept that MITE sequences can be useful in engineering genetic tools to deliver cargo genes into eukaryotic genomes.
Collapse
Affiliation(s)
- Isam Fattash
- Department of Biology, University of Toronto Mississauga, Mississauga, Canada
| | - Priyanka Bhardwaj
- Department of Biology, University of Toronto Mississauga, Mississauga, Canada
| | - Caleb Hui
- Department of Biology, University of Toronto Mississauga, Mississauga, Canada
| | - Guojun Yang
- Department of Biology, University of Toronto Mississauga, Mississauga, Canada
- * E-mail:
| |
Collapse
|
48
|
Jursch T, Miskey C, Izsvák Z, Ivics Z. Regulation of DNA transposition by CpG methylation and chromatin structure in human cells. Mob DNA 2013; 4:15. [PMID: 23676100 PMCID: PMC3680223 DOI: 10.1186/1759-8753-4-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 04/19/2013] [Indexed: 12/25/2022] Open
Abstract
Background The activity of transposable elements can be regulated by different means. DNA CpG methylation is known to decrease or inhibit transpositional activity of diverse transposons. However, very surprisingly, it was previously shown that CpG methylation of the Sleeping Beauty (SB) transposon significantly enhanced transposition in mouse embryonic stem cells. Results In order to investigate the unexpected response of SB transposition to CpG methylation, related transposons from the Tc1/mariner superfamily, that is, Tc1, Himar1, Hsmar1, Frog Prince (FP) and Minos were tested to see how transposition was affected by CpG methylation. A significant increase of >20-fold in transposition of SB, FP and Minos was seen, whereas Tc1, Himar1 and Hsmar1 showed no difference in transposition upon CpG-methylation. The terminal inverted repeats (TIRs) of the SB, FP and Minos elements share a common structure, in which each TIR contains two functionally important binding sites for the transposase (termed the IR/DR structure). The group of IR/DR elements showed increased excision after CpG methylation compared to untreated transposon donor plasmids. We found that de novo CpG methylation is not required for transposition. A mutated FP donor plasmid with depleted CpG sites in both TIRs was as efficient in transposition as the wild-type transposon, indicating that CpG sites inside the TIRs are not responsible for altered binding of factors potentially modulating transposition. By using an in vivo one-hybrid DNA-binding assay in cultured human cells we found that CpG methylation had no appreciable effect on the affinity of SB transposase to its binding sites. However, chromatin immunoprecipitation indicated that CpG-methylated transposon donor plasmids are associated with a condensed chromatin structure characterized by trimethylated histone H3K9. Finally, DNA compaction by protamine was found to enhance SB transposition. Conclusions We have shown that DNA CpG methylation upregulates transposition of IR/DR elements in the Tc1/mariner superfamily. CpG methylation provokes the formation of a tight chromatin structure at the transposon DNA, likely aiding the formation of a catalytically active complex by facilitating synapsis of sites bound by the transposase.
Collapse
Affiliation(s)
- Tobias Jursch
- Max Delbrück Center for Molecular Medicine, D-13125, Berlin, Germany.
| | | | | | | |
Collapse
|
49
|
Identification of multiple binding sites for the THAP domain of the Galileo transposase in the long terminal inverted-repeats. Gene 2013; 525:84-91. [PMID: 23648487 PMCID: PMC3688188 DOI: 10.1016/j.gene.2013.04.050] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 04/15/2013] [Accepted: 04/17/2013] [Indexed: 11/21/2022]
Abstract
Galileo is a DNA transposon responsible for the generation of several chromosomal inversions in Drosophila. In contrast to other members of the P-element superfamily, it has unusually long terminal inverted-repeats (TIRs) that resemble those of Foldback elements. To investigate the function of the long TIRs we derived consensus and ancestral sequences for the Galileo transposase in three species of Drosophilids. Following gene synthesis, we expressed and purified their constituent THAP domains and tested their binding activity towards the respective Galileo TIRs. DNase I footprinting located the most proximal DNA binding site about 70 bp from the transposon end. Using this sequence we identified further binding sites in the tandem repeats that are found within the long TIRs. This suggests that the synaptic complex between Galileo ends may be a complicated structure containing higher-order multimers of the transposase. We also attempted to reconstitute Galileo transposition in Drosophila embryos but no events were detected. Thus, although the limited numbers of Galileo copies in each genome were sufficient to provide functional consensus sequences for the THAP domains, they do not specify a fully active transposase. Since the THAP recognition sequence is short, and will occur many times in a large genome, it seems likely that the multiple binding sites within the long, internally repetitive, TIRs of Galileo and other Foldback-like elements may provide the transposase with its binding specificity.
Collapse
|
50
|
Fattash I, Rooke R, Wong A, Hui C, Luu T, Bhardwaj P, Yang G. Miniature inverted-repeat transposable elements: discovery, distribution, and activity. Genome 2013; 56:475-86. [PMID: 24168668 DOI: 10.1139/gen-2012-0174] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Eukaryotic organisms have dynamic genomes, with transposable elements (TEs) as a major contributing factor. Although the large autonomous TEs can significantly shape genomic structures during evolution, genomes often harbor more miniature nonautonomous TEs that can infest genomic niches where large TEs are rare. In spite of their cut-and-paste transposition mechanisms that do not inherently favor copy number increase, miniature inverted-repeat transposable elements (MITEs) are abundant in eukaryotic genomes and exist in high copy numbers. Based on the large number of MITE families revealed in previous studies, accurate annotation of MITEs, particularly in newly sequenced genomes, will identify more genomes highly rich in these elements. Novel families identified from these analyses, together with the currently known families, will further deepen our understanding of the origins, transposase sources, and dramatic amplification of these elements.
Collapse
Affiliation(s)
- Isam Fattash
- a Department of Biology, University of Toronto at Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | | | | | | | | | | | | |
Collapse
|