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Tang W, Liang P. The identification of retro-DNAs in primate genomes as DNA transposons mobilizing via retrotransposition. F1000Res 2024; 12:255. [PMID: 38915770 PMCID: PMC11195612 DOI: 10.12688/f1000research.130043.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/23/2024] [Indexed: 06/26/2024] Open
Abstract
Background Mobile elements (MEs) constitute a major portion of the genome in primates and other higher eukaryotes, and they play important role in genome evolution and gene function. MEs can be divided into two fundamentally different classes: DNA transposons which transpose in the genome in a "cut-and-paste" style, and retrotransposons which propagate in a "copy-and-paste" fashion via a process involving transcription and reverse-transcription. In primate genomes, DNA transposons are mostly dead, while many retrotransposons are still highly active. We report here the identification of a unique group of MEs, which we call "retro-DNAs", for their combined characteristics of these two fundamentally different ME classes. Methods A comparative computational genomic approach was used to analyze the reference genome sequences of 10 primate species consisting of five apes, four monkeys, and marmoset. Results From our analysis, we identified a total of 1,750 retro-DNAs, representing 748 unique insertion events in the genomes of ten primate species including human. These retro-DNAs contain sequences of DNA transposons but lack the terminal inverted repeats (TIRs), the hallmark of DNA transposons. Instead, they show characteristics of retrotransposons, such as polyA tails, longer target-site duplications (TSDs), and the "TT/AAAA" insertion site motif, suggesting the use of the L1-based target- primed reverse transcription (TPRT) mechanism. At least 40% of these retro-DNAs locate into genic regions, presenting potentials for impacting gene function. More interestingly, some retro-DNAs, as well as their parent sites, show certain levels of expression, suggesting that they have the potential to create more retro-DNA copies in the present primate genomes. Conclusions Although small in number, the identification of these retro-DNAs reveals a new mean for propagating DNA transposons in primate genomes without active canonical DNA transposon activity. Our data also suggest that the TPRT machinery may transpose a wider variety of DNA sequences in the genomes.
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Affiliation(s)
- Wangxiangfu Tang
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, L2S 3A1, Canada
| | - Ping Liang
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, L2S 3A1, Canada
- Centre of Biotechnology, Brock University, St. Catharines, Ontario, L2S 3A1, Canada
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2
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Zong W, Zhao R, Wang X, Zhou C, Wang J, Chen C, Niu N, Zheng Y, Chen L, Liu X, Hou X, Zhao F, Wang L, Wang L, Song C, Zhang L. Population genetic analysis based on the polymorphisms mediated by transposons in the genomes of pig. DNA Res 2024; 31:dsae008. [PMID: 38447059 PMCID: PMC11090087 DOI: 10.1093/dnares/dsae008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 02/28/2024] [Accepted: 03/05/2024] [Indexed: 03/08/2024] Open
Abstract
Transposable elements (TEs) mobility is capable of generating a large number of structural variants (SVs), which can have considerable potential as molecular markers for genetic analysis and molecular breeding in livestock. Our results showed that the pig genome contains mainly TE-SVs generated by short interspersed nuclear elements (51,873/76.49%), followed by long interspersed nuclear elements (11,131/16.41%), and more than 84% of the common TE-SVs (Minor allele frequency, MAF > 0.10) were validated to be polymorphic. Subsequently, we utilized the identified TE-SVs to gain insights into the population structure, resulting in clear differentiation among the three pig groups and facilitating the identification of relationships within Chinese local pig breeds. In addition, we investigated the frequencies of TEs in the gene coding regions of different pig groups and annotated the respective TE types, related genes, and functional pathways. Through genome-wide comparisons of Large White pigs and Chinese local pigs utilizing the Beijing Black pigs, we identified TE-mediated SVs associated with quantitative trait loci and observed that they were mainly involved in carcass traits and meat quality traits. Lastly, we present the first documented evidence of TE transduction in the pig genome.
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Affiliation(s)
- Wencheng Zong
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Runze Zhao
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
- College of Animal Science, Shanxi Agricultural University, Jinzhong, China
| | - Xiaoyan Wang
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Chenyu Zhou
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Jinbu Wang
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Cai Chen
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Naiqi Niu
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Yao Zheng
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Li Chen
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
- Chongqing Academy of Animal Science, Chongqing, China
| | - Xin Liu
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Xinhua Hou
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Fuping Zhao
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Ligang Wang
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Lixian Wang
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Chengyi Song
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Longchao Zhang
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
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Halabian R, Makałowski W. A Map of 3' DNA Transduction Variants Mediated by Non-LTR Retroelements on 3202 Human Genomes. BIOLOGY 2022; 11:1032. [PMID: 36101413 PMCID: PMC9311842 DOI: 10.3390/biology11071032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/05/2022] [Accepted: 07/06/2022] [Indexed: 05/03/2023]
Abstract
As one of the major structural constituents, mobile elements comprise more than half of the human genome, among which Alu, L1, and SVA elements are still active and continue to generate new offspring. One of the major characteristics of L1 and SVA elements is their ability to co-mobilize adjacent downstream sequences to new loci in a process called 3' DNA transduction. Transductions influence the structure and content of the genome in different ways, such as increasing genome variation, exon shuffling, and gene duplication. Moreover, given their mutagenicity capability, 3' transductions are often involved in tumorigenesis or in the development of some diseases. In this study, we analyzed 3202 genomes sequenced at high coverage by the New York Genome Center to catalog and characterize putative 3' transduced segments mediated by L1s and SVAs. Here, we present a genome-wide map of inter/intrachromosomal 3' transduction variants, including their genomic and functional location, length, progenitor location, and allelic frequency across 26 populations. In total, we identified 7103 polymorphic L1s and 3040 polymorphic SVAs. Of these, 268 and 162 variants were annotated as high-confidence L1 and SVA 3' transductions, respectively, with lengths that ranged from 7 to 997 nucleotides. We found specific loci within chromosomes X, 6, 7, and 6_GL000253v2_alt as master L1s and SVAs that had yielded more transductions, among others. Together, our results demonstrate the dynamic nature of transduction events within the genome and among individuals and their contribution to the structural variations of the human genome.
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Affiliation(s)
| | - Wojciech Makałowski
- Institute of Bioinformatics, Faculty of Medicine, University of Münster, 48149 Münster, Germany;
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4
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Hoyt SJ, Storer JM, Hartley GA, Grady PGS, Gershman A, de Lima LG, Limouse C, Halabian R, Wojenski L, Rodriguez M, Altemose N, Rhie A, Core LJ, Gerton JL, Makalowski W, Olson D, Rosen J, Smit AFA, Straight AF, Vollger MR, Wheeler TJ, Schatz MC, Eichler EE, Phillippy AM, Timp W, Miga KH, O’Neill RJ. From telomere to telomere: The transcriptional and epigenetic state of human repeat elements. Science 2022; 376:eabk3112. [PMID: 35357925 PMCID: PMC9301658 DOI: 10.1126/science.abk3112] [Citation(s) in RCA: 121] [Impact Index Per Article: 60.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mobile elements and repetitive genomic regions are sources of lineage-specific genomic innovation and uniquely fingerprint individual genomes. Comprehensive analyses of such repeat elements, including those found in more complex regions of the genome, require a complete, linear genome assembly. We present a de novo repeat discovery and annotation of the T2T-CHM13 human reference genome. We identified previously unknown satellite arrays, expanded the catalog of variants and families for repeats and mobile elements, characterized classes of complex composite repeats, and located retroelement transduction events. We detected nascent transcription and delineated CpG methylation profiles to define the structure of transcriptionally active retroelements in humans, including those in centromeres. These data expand our insight into the diversity, distribution, and evolution of repetitive regions that have shaped the human genome.
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Affiliation(s)
- Savannah J. Hoyt
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | | | - Gabrielle A. Hartley
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Patrick G. S. Grady
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Ariel Gershman
- Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, MD, USA
| | | | - Charles Limouse
- Department of Biochemistry, Stanford University, Stanford, CA, USA
| | - Reza Halabian
- Institute of Bioinformatics, Faculty of Medicine, University of Münster, Münster, Germany
| | - Luke Wojenski
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Matias Rodriguez
- Institute of Bioinformatics, Faculty of Medicine, University of Münster, Münster, Germany
| | - Nicolas Altemose
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA
| | - Arang Rhie
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Leighton J. Core
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | | | - Wojciech Makalowski
- Institute of Bioinformatics, Faculty of Medicine, University of Münster, Münster, Germany
| | - Daniel Olson
- Department of Computer Science, University of Montana, Missoula, MT, USA
| | - Jeb Rosen
- Institute for Systems Biology, Seattle, WA, USA
| | | | | | - Mitchell R. Vollger
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Travis J. Wheeler
- Department of Computer Science, University of Montana, Missoula, MT, USA
| | - Michael C. Schatz
- Department of Computer Science and Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Evan E. Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Adam M. Phillippy
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Winston Timp
- Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Karen H. Miga
- UC Santa Cruz Genomics Institute, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Rachel J. O’Neill
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, USA
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5
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Retrotransposition disrupting EBP in a girl and her mother with X-linked dominant chondrodysplasia punctata. J Hum Genet 2022; 67:303-306. [PMID: 34999728 DOI: 10.1038/s10038-021-01000-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/06/2021] [Accepted: 11/24/2021] [Indexed: 11/08/2022]
Abstract
X-linked dominant chondrodysplasia punctata (CDPX2) is a rare congenital disorder caused by pathogenic variants in EBP on Xp11.23. We encountered a girl and her mother with CDPX2-compatible phenotypes including punctiform calcification in the neonatal period of the girl, and asymmetric limb shortening and ichthyosis following the Blaschko lines in both subjects. Although Sanger direct sequencing failed to reveal a disease-causing variant in EBP, whole genome sequencing (WGS) followed by Manta analysis identified a ~ 4.5 kb insertion at EBP exon 2 of both subjects. The insertion was associated with the hallmarks of retrotransposition such as an antisense poly(A) tail, a target site duplication, and a consensus endonuclease cleavage site, and the inserted sequence harbored full-length SVA_F1 element with 5'- and 3'-transductions containing the Alu sequence. The results imply the relevance of retrotransposition to the human genetic diseases and the usefulness of WGS in the identification of retrotransposition.
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6
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Halo JV, Pendleton AL, Shen F, Doucet AJ, Derrien T, Hitte C, Kirby LE, Myers B, Sliwerska E, Emery S, Moran JV, Boyko AR, Kidd JM. Long-read assembly of a Great Dane genome highlights the contribution of GC-rich sequence and mobile elements to canine genomes. Proc Natl Acad Sci U S A 2021; 118:e2016274118. [PMID: 33836575 PMCID: PMC7980453 DOI: 10.1073/pnas.2016274118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Technological advances have allowed improvements in genome reference sequence assemblies. Here, we combined long- and short-read sequence resources to assemble the genome of a female Great Dane dog. This assembly has improved continuity compared to the existing Boxer-derived (CanFam3.1) reference genome. Annotation of the Great Dane assembly identified 22,182 protein-coding gene models and 7,049 long noncoding RNAs, including 49 protein-coding genes not present in the CanFam3.1 reference. The Great Dane assembly spans the majority of sequence gaps in the CanFam3.1 reference and illustrates that 2,151 gaps overlap the transcription start site of a predicted protein-coding gene. Moreover, a subset of the resolved gaps, which have an 80.95% median GC content, localize to transcription start sites and recombination hotspots more often than expected by chance, suggesting the stable canine recombinational landscape has shaped genome architecture. Alignment of the Great Dane and CanFam3.1 assemblies identified 16,834 deletions and 15,621 insertions, as well as 2,665 deletions and 3,493 insertions located on secondary contigs. These structural variants are dominated by retrotransposon insertion/deletion polymorphisms and include 16,221 dimorphic canine short interspersed elements (SINECs) and 1,121 dimorphic long interspersed element-1 sequences (LINE-1_Cfs). Analysis of sequences flanking the 3' end of LINE-1_Cfs (i.e., LINE-1_Cf 3'-transductions) suggests multiple retrotransposition-competent LINE-1_Cfs segregate among dog populations. Consistent with this conclusion, we demonstrate that a canine LINE-1_Cf element with intact open reading frames can retrotranspose its own RNA and that of a SINEC_Cf consensus sequence in cultured human cells, implicating ongoing retrotransposon activity as a driver of canine genetic variation.
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Affiliation(s)
- Julia V Halo
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - Amanda L Pendleton
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - Feichen Shen
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - Aurélien J Doucet
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
- Université Côte d'Azur, CNRS, INSERM, Institut de Recherche sur le Cancer et le Vieillissement de Nice, F-06100 Nice, France
| | - Thomas Derrien
- Université de Rennes 1, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, F-35000 Rennes, France
| | - Christophe Hitte
- Université de Rennes 1, CNRS, Institut de Génétique et Développement de Rennes-UMR 6290, F-35000 Rennes, France
| | - Laura E Kirby
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - Bridget Myers
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - Elzbieta Sliwerska
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - Sarah Emery
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
| | - John V Moran
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Adam R Boyko
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14850
| | - Jeffrey M Kidd
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109;
- Department Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109
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7
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Tang W, Liang P. Comparative Genomics Analysis Reveals High Levels of Differential Retrotransposition among Primates from the Hominidae and the Cercopithecidae Families. Genome Biol Evol 2019; 11:3309-3325. [PMID: 31651947 PMCID: PMC6934888 DOI: 10.1093/gbe/evz234] [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] [Accepted: 10/24/2019] [Indexed: 12/11/2022] Open
Abstract
Mobile elements (MEs), making ∼50% of primate genomes, are known to be responsible for generating inter- and intra-species genomic variations and play important roles in genome evolution and gene function. Using a bioinformatics comparative genomics approach, we performed analyses of species-specific MEs (SS-MEs) in eight primate genomes from the families of Hominidae and Cercopithecidae, focusing on retrotransposons. We identified a total of 230,855 SS-MEs, with which we performed normalization based on evolutionary distances, and we also analyzed the most recent SS-MEs in these genomes. Comparative analysis of SS-MEs reveals striking differences in ME transposition among these primate genomes. Interesting highlights of our results include: 1) the baboon genome has the highest number of SS-MEs with a strong bias for SINEs, while the crab-eating macaque genome has a sustained extremely low transposition for all ME classes, suggesting the existence of a genome-wide mechanism suppressing ME transposition; 2) while SS-SINEs represent the dominant class in general, the orangutan genome stands out by having SS-LINEs as the dominant class; 3) the human genome stands out among the eight genomes by having the largest number of recent highly active ME subfamilies, suggesting a greater impact of ME transposition on its recent evolution; and 4) at least 33% of the SS-MEs locate to genic regions, including protein coding regions, presenting significant potentials for impacting gene function. Our study, as the first of its kind, demonstrates that mobile elements evolve quite differently among these primates, suggesting differential ME transposition as an important mechanism in primate evolution.
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Affiliation(s)
| | - Ping Liang
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada
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8
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Kim S, Mun S, Kim T, Lee KH, Kang K, Cho JY, Han K. Transposable element-mediated structural variation analysis in dog breeds using whole-genome sequencing. Mamm Genome 2019; 30:289-300. [PMID: 31414176 DOI: 10.1007/s00335-019-09812-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 07/23/2019] [Indexed: 12/26/2022]
Abstract
Naturally occurring diseases in dogs provide an important animal model for studying human disease including cancer, heart disease, and autoimmune disorders. Transposable elements (TEs) make up ~ 31% of the dog (Canis lupus familiaris) genome and are one of main drivers to cause genomic variations and alter gene expression patterns of the host genes, which could result in genetic diseases. To detect structural variations (SVs), we conducted whole-genome sequencing of three different breeds, including Maltese, Poodle, and Yorkshire Terrier. Genomic SVs were detected and visualized using BreakDancer program. We identified a total of 2328 deletion SV events in the three breeds compared with the dog reference genome of Boxer. The majority of the genetic variants were found to be TE insertion polymorphism (1229) and the others were TE-mediated deletion (489), non-TE-mediated deletion (542), simple repeat-mediated deletion (32), and other indel (36). Among the TE insertion polymorphism, 286 elements were full-length LINE-1s (L1s). In addition, the 49 SV candidates located in the genic regions were experimentally verified and their polymorphic rates within each breed were examined using PCR assay. Polymorphism analysis of the genomic variants revealed that some of the variants exist polymorphic in the three dog breeds, suggesting that their SV events recently occurred in the dog genome. The findings suggest that TEs have contributed to the genomic variations among the three dog breeds of Maltese, Poodle, and Yorkshire Terrier. In addition, the polymorphic events between the dog breeds indicate that TEs were recently retrotransposed in the dog genome.
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Affiliation(s)
- Songmi Kim
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea
| | - Seyoung Mun
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea
| | - Taemook Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Kang-Hoon Lee
- Department of Biochemistry, BK21 PLUS Program for Creative Veterinary Science Research and Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Keunsoo Kang
- Department of Microbiology, Dankook University, Cheonan, 31116, Republic of Korea
| | - Je-Yoel Cho
- Department of Biochemistry, BK21 PLUS Program for Creative Veterinary Science Research and Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.
| | - Kyudong Han
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea.
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9
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Matsuno Y, Yamashita T, Wagatsuma M, Yamakage H. Convergence in LINE-1 nucleotide variations can benefit redundantly forming triplexes with lncRNA in mammalian X-chromosome inactivation. Mob DNA 2019; 10:33. [PMID: 31384315 PMCID: PMC6664574 DOI: 10.1186/s13100-019-0173-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 07/08/2019] [Indexed: 01/01/2023] Open
Abstract
Background Associations between X-inactive transcript (Xist)–long noncoding RNA (lncRNA) and chromatin are critical intermolecular interactions in the X-chromosome inactivation (XCI) process. Despite high-resolution analyses of the Xist RNA-binding sites, specific interaction sequences are yet to be identified. Based on elusive features of the association between Xist RNA and chromatin and the possible existence of multiple low-affinity binding sites in Xist RNA, we defined short motifs (≥5 nucleotides), termed as redundant UC/TC (r-UC/TC) or AG (r-AG) motifs, which may help in the mediation of triplex formation between the lncRNAs and duplex DNA. Results The study showed that r-UC motifs are densely dispersed throughout mouse and human Xist/XIST RNAs, whereas r-AG motifs are even more densely dispersed along opossum RNA-on-the-silent X (Rsx) RNA, and also along both full-length and truncated long interspersed nuclear elements (LINE-1s, L1s) of the three species. Predicted secondary structures of the lncRNAs showed that the length range of these sequence motifs available for forming triplexes was even shorter, mainly 5- to 9-nucleotides long. Quartz crystal microbalance (QCM) measurements and Monte Carlo (MC) simulations indicated that minimum-length motifs can reinforce the binding state by increasing the copy number of the motifs in the same RNA or DNA molecule. Further, r-AG motifs in L1s had a similar length-distribution pattern, regardless of the similarities in the length or sequence of L1s across the three species; this also applies to high-frequency mutations in r-AG motifs, which suggests convergence in L1 sequence variations. Conclusions Multiple short motifs in both RNA and duplex DNA molecules could be brought together to form triplexes with either Hoogsteen or reverse Hoogsteen hydrogen bonding, by which their associations are cooperatively enhanced. This novel triplex interaction could be involved in associations between lncRNA and chromatin in XCI, particularly at the sites of L1s. Potential binding of Xist/XIST/Rsx RNAs specifically at L1s is most likely preserved through the r-AG motifs conserved in mammalian L1s through convergence in L1 nucleotide variations and by maintaining a particular r-UC/r-AG motif ratio in each of these lncRNAs, irrespective of their poorly conserved sequences. Electronic supplementary material The online version of this article (10.1186/s13100-019-0173-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yoko Matsuno
- 1Division of Clinical Preventive Medicine, Niigata University, Niigata, Japan
| | - Takefumi Yamashita
- 2Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
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10
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Gagnier L, Belancio VP, Mager DL. Mouse germ line mutations due to retrotransposon insertions. Mob DNA 2019; 10:15. [PMID: 31011371 PMCID: PMC6466679 DOI: 10.1186/s13100-019-0157-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/01/2019] [Indexed: 12/24/2022] Open
Abstract
Transposable element (TE) insertions are responsible for a significant fraction of spontaneous germ line mutations reported in inbred mouse strains. This major contribution of TEs to the mutational landscape in mouse contrasts with the situation in human, where their relative contribution as germ line insertional mutagens is much lower. In this focussed review, we provide comprehensive lists of TE-induced mouse mutations, discuss the different TE types involved in these insertional mutations and elaborate on particularly interesting cases. We also discuss differences and similarities between the mutational role of TEs in mice and humans.
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Affiliation(s)
- Liane Gagnier
- Terry Fox Laboratory, BC Cancer and Department of Medical Genetics, University of British Columbia, V5Z1L3, Vancouver, BC Canada
| | - Victoria P. Belancio
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, Tulane Center for Aging, New Orleans, LA 70112 USA
| | - Dixie L. Mager
- Terry Fox Laboratory, BC Cancer and Department of Medical Genetics, University of British Columbia, V5Z1L3, Vancouver, BC Canada
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11
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Dynamic Methylation of an L1 Transduction Family during Reprogramming and Neurodifferentiation. Mol Cell Biol 2019; 39:MCB.00499-18. [PMID: 30692270 PMCID: PMC6425141 DOI: 10.1128/mcb.00499-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/11/2019] [Indexed: 01/28/2023] Open
Abstract
The retrotransposon LINE-1 (L1) is a significant source of endogenous mutagenesis in humans. In each individual genome, a few retrotransposition-competent L1s (RC-L1s) can generate new heritable L1 insertions in the early embryo, primordial germ line, and germ cells. L1 retrotransposition can also occur in the neuronal lineage and cause somatic mosaicism. Although DNA methylation mediates L1 promoter repression, the temporal pattern of methylation applied to individual RC-L1s during neurogenesis is unclear. Here, we identified a de novo L1 insertion in a human induced pluripotent stem cell (hiPSC) line via retrotransposon capture sequencing (RC-seq). The L1 insertion was full-length and carried 5' and 3' transductions. The corresponding donor RC-L1 was part of a large and recently active L1 transduction family and was highly mobile in a cultured-cell L1 retrotransposition reporter assay. Notably, we observed distinct and dynamic DNA methylation profiles for the de novo L1 and members of its extended transduction family during neuronal differentiation. These experiments reveal how a de novo L1 insertion in a pluripotent stem cell is rapidly recognized and repressed, albeit incompletely, by the host genome during neurodifferentiation, while retaining potential for further retrotransposition.
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Abstract
Transposable elements (TEs) are ubiquitous in both prokaryotes and eukaryotes, and the dynamic character of their interaction with host genomes brings about numerous evolutionary innovations and shapes genome structure and function in a multitude of ways. In traditional classification systems, TEs are often being depicted in simplistic ways, based primarily on the key enzymes required for transposition, such as transposases/recombinases and reverse transcriptases. Recent progress in whole-genome sequencing and long-read assembly, combined with expansion of the familiar range of model organisms, resulted in identification of unprecedentedly long transposable units spanning dozens or even hundreds of kilobases, initially in prokaryotic and more recently in eukaryotic systems. Here, we focus on such oversized eukaryotic TEs, including retrotransposons and DNA transposons, outline their complex and often combinatorial nature and closely intertwined relationship with viruses, and discuss their potential for participating in transfer of long stretches of DNA in eukaryotes.
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Affiliation(s)
- Irina R Arkhipova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, Massachusetts
- Corresponding author: E-mail:
| | - Irina A Yushenova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, Massachusetts
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Tang W, Mun S, Joshi A, Han K, Liang P. Mobile elements contribute to the uniqueness of human genome with 15,000 human-specific insertions and 14 Mbp sequence increase. DNA Res 2019; 25:521-533. [PMID: 30052927 PMCID: PMC6191304 DOI: 10.1093/dnares/dsy022] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 06/20/2018] [Indexed: 02/02/2023] Open
Abstract
Mobile elements (MEs) collectively contribute to at least 50% of the human genome. Due to their past incremental accumulation and ongoing DNA transposition, MEs serve as a significant source for both inter- and intra-species genetic and phenotypic diversity during primate and human evolution. By making use of the most recent genome sequences for human and many other closely related primates and robust multi-way comparative genomic approach, we identified a total of 14,870 human-specific MEs (HS-MEs) with more than 8,000 being newly identified. Collectively, these HS-MEs contribute to a total of 14.2 Mbp net genome sequence increase. Several new observations were made based on these HS-MEs, including the finding of Y chromosome as a strikingly hot target for HS-MEs and a strong mutual preference for SINE-R/VNTR/Alu (SVAs). Furthermore, ∼8,000 of these HS-MEs were found to locate in the vicinity of ∼4,900 genes, and collectively they contribute to ∼84 kb sequences in the human reference transcriptome in association with over 300 genes, including protein-coding sequences for 40 genes. In conclusion, our results demonstrate that MEs made a significant contribution to the evolution of human genome by participating in gene function in a human-specific fashion.
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Affiliation(s)
- Wanxiangfu Tang
- Department of Biological Sciences, Brock University, St. Catharines, ON, Canada
| | - Seyoung Mun
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research, Center for Regenerative Medicine, Dankook University, Cheonan, Republic of Korea
| | - Aditya Joshi
- Department of Biological Sciences, Brock University, St. Catharines, ON, Canada
| | - Kyudong Han
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research, Center for Regenerative Medicine, Dankook University, Cheonan, Republic of Korea
| | - Ping Liang
- Department of Biological Sciences, Brock University, St. Catharines, ON, Canada
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Next-generation sequencing-based detection of germline L1-mediated transductions. BMC Genomics 2016; 17:342. [PMID: 27161561 PMCID: PMC4862182 DOI: 10.1186/s12864-016-2670-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 04/26/2016] [Indexed: 01/01/2023] Open
Abstract
Background While active LINE-1 (L1) elements possess the ability to mobilize flanking sequences to different genomic loci through a process termed transduction influencing genomic content and structure, an approach for detecting polymorphic germline non-reference transductions in massively-parallel sequencing data has been lacking. Results Here we present the computational approach TIGER (Transduction Inference in GERmline genomes), enabling the discovery of non-reference L1-mediated transductions by combining L1 discovery with detection of unique insertion sequences and detailed characterization of insertion sites. We employed TIGER to characterize polymorphic transductions in fifteen genomes from non-human primate species (chimpanzee, orangutan and rhesus macaque), as well as in a human genome. We achieved high accuracy as confirmed by PCR and two single molecule DNA sequencing techniques, and uncovered differences in relative rates of transduction between primate species. Conclusions By enabling detection of polymorphic transductions, TIGER makes this form of relevant structural variation amenable for population and personal genome analysis. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2670-x) contains supplementary material, which is available to authorized users.
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Hancks DC, Kazazian HH. Roles for retrotransposon insertions in human disease. Mob DNA 2016; 7:9. [PMID: 27158268 PMCID: PMC4859970 DOI: 10.1186/s13100-016-0065-9] [Citation(s) in RCA: 421] [Impact Index Per Article: 52.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/14/2016] [Indexed: 12/12/2022] Open
Abstract
Over evolutionary time, the dynamic nature of a genome is driven, in part, by the activity of transposable elements (TE) such as retrotransposons. On a shorter time scale it has been established that new TE insertions can result in single-gene disease in an individual. In humans, the non-LTR retrotransposon Long INterspersed Element-1 (LINE-1 or L1) is the only active autonomous TE. In addition to mobilizing its own RNA to new genomic locations via a "copy-and-paste" mechanism, LINE-1 is able to retrotranspose other RNAs including Alu, SVA, and occasionally cellular RNAs. To date in humans, 124 LINE-1-mediated insertions which result in genetic diseases have been reported. Disease causing LINE-1 insertions have provided a wealth of insight and the foundation for valuable tools to study these genomic parasites. In this review, we provide an overview of LINE-1 biology followed by highlights from new reports of LINE-1-mediated genetic disease in humans.
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Affiliation(s)
- Dustin C. Hancks
- />Eccles Institute of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT USA
| | - Haig H. Kazazian
- />McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins School of Medicine, Baltimore, MD USA
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16
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Tubio JMC, Li Y, Ju YS, Martincorena I, Cooke SL, Tojo M, Gundem G, Pipinikas CP, Zamora J, Raine K, Menzies A, Roman-Garcia P, Fullam A, Gerstung M, Shlien A, Tarpey PS, Papaemmanuil E, Knappskog S, Van Loo P, Ramakrishna M, Davies HR, Marshall J, Wedge DC, Teague JW, Butler AP, Nik-Zainal S, Alexandrov L, Behjati S, Yates LR, Bolli N, Mudie L, Hardy C, Martin S, McLaren S, O'Meara S, Anderson E, Maddison M, Gamble S, Foster C, Warren AY, Whitaker H, Brewer D, Eeles R, Cooper C, Neal D, Lynch AG, Visakorpi T, Isaacs WB, Veer LV, Caldas C, Desmedt C, Sotiriou C, Aparicio S, Foekens JA, Eyfjörd JE, Lakhani SR, Thomas G, Myklebost O, Span PN, Børresen-Dale AL, Richardson AL, Van de Vijver M, Vincent-Salomon A, Van den Eynden GG, Flanagan AM, Futreal PA, Janes SM, Bova GS, Stratton MR, McDermott U, Campbell PJ. Mobile DNA in cancer. Extensive transduction of nonrepetitive DNA mediated by L1 retrotransposition in cancer genomes. Science 2014; 345:1251343. [PMID: 25082706 PMCID: PMC4380235 DOI: 10.1126/science.1251343] [Citation(s) in RCA: 285] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Long interspersed nuclear element-1 (L1) retrotransposons are mobile repetitive elements that are abundant in the human genome. L1 elements propagate through RNA intermediates. In the germ line, neighboring, nonrepetitive sequences are occasionally mobilized by the L1 machinery, a process called 3' transduction. Because 3' transductions are potentially mutagenic, we explored the extent to which they occur somatically during tumorigenesis. Studying cancer genomes from 244 patients, we found that tumors from 53% of the patients had somatic retrotranspositions, of which 24% were 3' transductions. Fingerprinting of donor L1s revealed that a handful of source L1 elements in a tumor can spawn from tens to hundreds of 3' transductions, which can themselves seed further retrotranspositions. The activity of individual L1 elements fluctuated during tumor evolution and correlated with L1 promoter hypomethylation. The 3' transductions disseminated genes, exons, and regulatory elements to new locations, most often to heterochromatic regions of the genome.
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Affiliation(s)
| | - Yilong Li
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Young Seok Ju
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | | | | | - Marta Tojo
- Department of Physiology, School of Medicine–Center for Resesarch in Molecular Medicine and Chronic Diseases, Instituto de Investigaciones Sanitarias, University of Santiago de Compostela, Spain
| | - Gunes Gundem
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | | | - Jorge Zamora
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Keiran Raine
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Andrew Menzies
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | | | - Anthony Fullam
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Moritz Gerstung
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Adam Shlien
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | | | | | - Stian Knappskog
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Oncology, Haukeland University Hospital, Bergen, Norway
| | - Peter Van Loo
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
- Human Genome Laboratory, Department of Human Genetics, VIB and KU Leuven, Leuven, Belgium
| | | | - Helen R. Davies
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - John Marshall
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - David C. Wedge
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Jon W. Teague
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Adam P. Butler
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Serena Nik-Zainal
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
- Cambridge University Hospitals National Health Service (NHS) Foundation Trust, Cambridge, UK
| | | | - Sam Behjati
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Lucy R. Yates
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Niccolo Bolli
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | - Laura Mudie
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Claire Hardy
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Sancha Martin
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Stuart McLaren
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Sarah O'Meara
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | | | - Mark Maddison
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Stephen Gamble
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | | | - Anne Y. Warren
- Cambridge University Hospitals National Health Service (NHS) Foundation Trust, Cambridge, UK
| | - Hayley Whitaker
- Cancer Research UK (CRUK) Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Daniel Brewer
- Institute of Cancer Research, Sutton, London, UK
- University of East Anglia, Norwich, UK
| | | | - Colin Cooper
- Institute of Cancer Research, Sutton, London, UK
- University of East Anglia, Norwich, UK
| | - David Neal
- Cancer Research UK (CRUK) Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Andy G. Lynch
- Cancer Research UK (CRUK) Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Tapio Visakorpi
- Institute of Biosciences and Medical Technology–BioMediTech, University of Tampere and Tampere University Hospital, Tampere, Finland
| | | | | | - Carlos Caldas
- Cancer Research UK (CRUK) Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Christine Desmedt
- Breast Cancer Translational Research Laboratory, Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium
| | - Christos Sotiriou
- Breast Cancer Translational Research Laboratory, Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium
| | - Sam Aparicio
- British Columbia Cancer Agency, Vancouver, Canada
| | - John A. Foekens
- Department of Medical Oncology, Erasmus Medical Center Cancer Institute, Erasmus University Medical Center, Rotterdam, Netherlands
| | | | - Sunil R. Lakhani
- School of Medicine, University of Queensland, Brisbane, Australia
- Pathology Queensland, Royal Brisbane and Women’s Hospital, Brisbane, Australia
- UQ Centre for Clinical Research, University of Queensland, Brisbane, Australia
| | - Gilles Thomas
- Université Lyon 1, Institut National du Cancer (INCa)–Synergie, Lyon, France
| | - Ola Myklebost
- Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Paul N. Span
- Department of Radiation Oncology and Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | | | | | - Marc Van de Vijver
- Department of Pathology, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, Netherlands
| | - Anne Vincent-Salomon
- Institut Bergonié, 229 cours de l’Argone, 33076 Bordeaux, France
- Institut Curie, Department of Tumor Biology, 26 rue d’Ulm, 75248 Paris cédex 05, France
| | - Gert G. Van den Eynden
- Translational Cancer Research Unit and Department of Pathology, GZA Hospitals, Antwerp, Belgium
| | - Adrienne M. Flanagan
- Royal National Orthopaedic Hospital, Middlesex, UK
- UCL Cancer Institute, University College London, London, UK
| | - P. Andrew Futreal
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
- MD Anderson Cancer Center, Houston, TX, USA
| | - Sam M. Janes
- Lungs for Living Research Centre, Rayne Institute, University College London (UCL), London, UK
| | - G. Steven Bova
- Institute of Biosciences and Medical Technology–BioMediTech, University of Tampere and Tampere University Hospital, Tampere, Finland
| | | | - Ultan McDermott
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Peter J. Campbell
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
- Cambridge University Hospitals National Health Service (NHS) Foundation Trust, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
| | | | | | - ICGC Prostate Cancer Group
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
- Institute of Cancer Research, Sutton, London, UK
- Cancer Research UK (CRUK) Cambridge Institute, University of Cambridge, Cambridge, UK
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17
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Egan JB, Barrett MT, Champion MD, Middha S, Lenkiewicz E, Evers L, Francis P, Schmidt J, Shi CX, Van Wier S, Badar S, Ahmann G, Kortuem KM, Boczek NJ, Fonseca R, Craig DW, Carpten JD, Borad MJ, Stewart AK. Whole genome analyses of a well-differentiated liposarcoma reveals novel SYT1 and DDR2 rearrangements. PLoS One 2014; 9:e87113. [PMID: 24505276 PMCID: PMC3914808 DOI: 10.1371/journal.pone.0087113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 12/22/2013] [Indexed: 12/30/2022] Open
Abstract
Liposarcoma is the most common soft tissue sarcoma, but little is known about the genomic basis of this disease. Given the low cell content of this tumor type, we utilized flow cytometry to isolate the diploid normal and aneuploid tumor populations from a well-differentiated liposarcoma prior to array comparative genomic hybridization and whole genome sequencing. This work revealed massive highly focal amplifications throughout the aneuploid tumor genome including MDM2, a gene that has previously been found to be amplified in well-differentiated liposarcoma. Structural analysis revealed massive rearrangement of chromosome 12 and 11 gene fusions, some of which may be part of double minute chromosomes commonly present in well-differentiated liposarcoma. We identified a hotspot of genomic instability localized to a region of chromosome 12 that includes a highly conserved, putative L1 retrotransposon element, LOC100507498 which resides within a gene cluster (NAV3, SYT1, PAWR) where 6 of the 11 fusion events occurred. Interestingly, a potential gene fusion was also identified in amplified DDR2, which is a potential therapeutic target of kinase inhibitors such as dastinib, that are not routinely used in the treatment of patients with liposarcoma. Furthermore, 7 somatic, damaging single nucleotide variants have also been identified, including D125N in the PTPRQ protein. In conclusion, this work is the first to report the entire genome of a well-differentiated liposarcoma with novel chromosomal rearrangements associated with amplification of therapeutically targetable genes such as MDM2 and DDR2.
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Affiliation(s)
- Jan B. Egan
- Comprehensive Cancer Center, Mayo Clinic, Scottsdale, Arizona, United States of America
| | - Michael T. Barrett
- Clinical Translational Research Division, Translational Genomics Research Institute, Phoenix, Arizona, United States of America
| | - Mia D. Champion
- Department of Biomedical Statistics and Informatics, Mayo Clinic, Scottsdale, Arizona, United States of America
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Sumit Middha
- Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Elizabeth Lenkiewicz
- Clinical Translational Research Division, Translational Genomics Research Institute, Phoenix, Arizona, United States of America
| | - Lisa Evers
- Clinical Translational Research Division, Translational Genomics Research Institute, Phoenix, Arizona, United States of America
| | - Princy Francis
- Research, Mayo Clinic, Scottsdale, Arizona, United States of America
| | - Jessica Schmidt
- Research, Mayo Clinic, Scottsdale, Arizona, United States of America
| | - Chang-Xin Shi
- Research, Mayo Clinic, Scottsdale, Arizona, United States of America
| | - Scott Van Wier
- Research, Mayo Clinic, Scottsdale, Arizona, United States of America
| | - Sandra Badar
- Research, Mayo Clinic, Scottsdale, Arizona, United States of America
| | - Gregory Ahmann
- Research, Mayo Clinic, Scottsdale, Arizona, United States of America
| | - K. Martin Kortuem
- Hematology, Mayo Clinic, Scottsdale, Arizona, United States of America
| | - Nicole J. Boczek
- Mayo Graduate School, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Rafael Fonseca
- Comprehensive Cancer Center, Mayo Clinic, Scottsdale, Arizona, United States of America
- Division of Hematology/Oncology Mayo Clinic, Scottsdale, Arizona, United States of America
| | - David W. Craig
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, Arizona, United States of America
| | - John D. Carpten
- Integrated Cancer Genomics Division, Translational Genomics Research Institute, Phoenix, Arizona, United States of America
| | - Mitesh J. Borad
- Comprehensive Cancer Center, Mayo Clinic, Scottsdale, Arizona, United States of America
- Division of Hematology/Oncology Mayo Clinic, Scottsdale, Arizona, United States of America
| | - A. Keith Stewart
- Comprehensive Cancer Center, Mayo Clinic, Scottsdale, Arizona, United States of America
- Division of Hematology/Oncology Mayo Clinic, Scottsdale, Arizona, United States of America
- * E-mail:
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18
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Mbanefo EC, Chuanxin Y, Kikuchi M, Shuaibu MN, Boamah D, Kirinoki M, Hayashi N, Chigusa Y, Osada Y, Hamano S, Hirayama K. Origin of a novel protein-coding gene family with similar signal sequence in Schistosoma japonicum. BMC Genomics 2012; 13:260. [PMID: 22716200 PMCID: PMC3434034 DOI: 10.1186/1471-2164-13-260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 06/11/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Evolution of novel protein-coding genes is the bedrock of adaptive evolution. Recently, we identified six protein-coding genes with similar signal sequence from Schistosoma japonicum egg stage mRNA using signal sequence trap (SST). To find the mechanism underlying the origination of these genes with similar core promoter regions and signal sequence, we adopted an integrated approach utilizing whole genome, transcriptome and proteome database BLAST queries, other bioinformatics tools, and molecular analyses. RESULTS Our data, in combination with database analyses showed evidences of expression of these genes both at the mRNA and protein levels exclusively in all developmental stages of S. japonicum. The signal sequence motif was identified in 27 distinct S. japonicum UniGene entries with multiple mRNA transcripts, and in 34 genome contigs distributed within 18 scaffolds with evidence of genome-wide dispersion. No homolog of these genes or similar domain was found in deposited data from any other organism. We observed preponderance of flanking repetitive elements (REs), albeit partial copies, especially of the RTE-like and Perere class at either side of the duplication source locus. The role of REs as major mediators of DNA-level recombination leading to dispersive duplication is discussed with evidence from our analyses. We also identified a stepwise pathway towards functional selection in evolving genes by alternative splicing. Equally, the possible transcription models of some protein-coding representatives of the duplicons are presented with evidence of expression in vitro. CONCLUSION Our findings contribute to the accumulating evidence of the role of REs in the generation of evolutionary novelties in organisms' genomes.
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Affiliation(s)
- Evaristus Chibunna Mbanefo
- Department of Immunogenetics, Institute of Tropical Medicine (NEKKEN), and Global COE Program, Nagasaki University, 1-12-4 Sakamoto, 852-8523, Nagasaki, Japan
- Department of Parasitology and Entomology, Faculty of Bioscience, Nnamdi Azikiwe University, P.M.B. 5025, Awka, Nigeria
| | - Yu Chuanxin
- Laboratory on Technology for Parasitic Disease Prevention and Control, Jiangsu Institute of Parasitic Diseases, 117 Yangxiang, Meiyuan, Wuxi, 214064, People's Republic of China
| | - Mihoko Kikuchi
- Department of Immunogenetics, Institute of Tropical Medicine (NEKKEN), and Global COE Program, Nagasaki University, 1-12-4 Sakamoto, 852-8523, Nagasaki, Japan
| | - Mohammed Nasir Shuaibu
- Department of Immunogenetics, Institute of Tropical Medicine (NEKKEN), and Global COE Program, Nagasaki University, 1-12-4 Sakamoto, 852-8523, Nagasaki, Japan
| | - Daniel Boamah
- Department of Immunogenetics, Institute of Tropical Medicine (NEKKEN), and Global COE Program, Nagasaki University, 1-12-4 Sakamoto, 852-8523, Nagasaki, Japan
| | - Masashi Kirinoki
- Laboratory of Tropical Medicine and Parasitology, Dokkyo Medical University, Tochigi, Japan
| | - Naoko Hayashi
- Laboratory of Tropical Medicine and Parasitology, Dokkyo Medical University, Tochigi, Japan
| | - Yuichi Chigusa
- Laboratory of Tropical Medicine and Parasitology, Dokkyo Medical University, Tochigi, Japan
| | - Yoshio Osada
- Department of Immunology and Parasitology, The University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Shinjiro Hamano
- Department of Parasitology, Institute of Tropical Medicine (NEKKEN), and Global COE Program, Nagasaki University, 1-12-4 Sakamoto, 852-8523, Nagasaki, Japan
| | - Kenji Hirayama
- Department of Immunogenetics, Institute of Tropical Medicine (NEKKEN), and Global COE Program, Nagasaki University, 1-12-4 Sakamoto, 852-8523, Nagasaki, Japan
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19
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Rawal K, Ramaswamy R. Genome-wide analysis of mobile genetic element insertion sites. Nucleic Acids Res 2011; 39:6864-78. [PMID: 21609951 PMCID: PMC3167599 DOI: 10.1093/nar/gkr337] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Mobile genetic elements (MGEs) account for a significant fraction of eukaryotic genomes and are implicated in altered gene expression and disease. We present an efficient computational protocol for MGE insertion site analysis. ELAN, the suite of tools described here uses standard techniques to identify different MGEs and their distribution on the genome. One component, DNASCANNER analyses known insertion sites of MGEs for the presence of signals that are based on a combination of local physical and chemical properties. ISF (insertion site finder) is a machine-learning tool that incorporates information derived from DNASCANNER. ISF permits classification of a given DNA sequence as a potential insertion site or not, using a support vector machine. We have studied the genomes of Homo sapiens, Mus musculus, Drosophila melanogaster and Entamoeba histolytica via a protocol whereby DNASCANNER is used to identify a common set of statistically important signals flanking the insertion sites in the various genomes. These are used in ISF for insertion site prediction, and the current accuracy of the tool is over 65%. We find similar signals at gene boundaries and splice sites. Together, these data are suggestive of a common insertion mechanism that operates in a variety of eukaryotes.
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Affiliation(s)
- Kamal Rawal
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
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20
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St Laurent G, Hammell N, McCaffrey TA. A LINE-1 component to human aging: do LINE elements exact a longevity cost for evolutionary advantage? Mech Ageing Dev 2010; 131:299-305. [PMID: 20346965 DOI: 10.1016/j.mad.2010.03.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 03/09/2010] [Accepted: 03/15/2010] [Indexed: 12/15/2022]
Abstract
Advancing age remains the largest risk factor for devastating diseases, such as heart disease, stroke, and cancer. The mechanisms by which advancing age predisposes to disease are now beginning to unfold, due in part, to genetic and environmental manipulations of longevity in lower organisms. Converging lines of evidence suggest that DNA damage may be a final common pathway linking several proposed mechanisms of aging. The present review forwards a theory for an additional aging pathway that involves modes of inherent genetic instability. Long interspersed nuclear elements (LINEs) are endogenous non-LTR retrotransposons that compose about 20% of the human genome. The LINE-1 (L1) gene products, ORF1p and ORF2p, possess mRNA binding, endonuclease, and reverse transcriptase activity that enable retrotransposition. While principally active only during embryogenesis, L1 transcripts are detected in adult somatic cells under certain conditions. The present hypothesis proposes that L1s act as an 'endogenous clock', slowly eroding genomic integrity by competing with the organism's double-strand break repair mechanism. Thus, while L1s are an accepted mechanism of genetic variation fueling evolution, it is proposed that longevity is negatively impacted by somatic L1 activity. The theory predicts testable hypotheses about the relationship between L1 activity, DNA repair, healthy aging, and longevity.
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Affiliation(s)
- Georges St Laurent
- The George Washington University Medical Center, Department of Medicine, Division of Genomic Medicine, 2300 I St. NW, Washington, DC 20037, United States
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Rangwala SH, Zhang L, Kazazian HH. Many LINE1 elements contribute to the transcriptome of human somatic cells. Genome Biol 2009; 10:R100. [PMID: 19772661 PMCID: PMC2768975 DOI: 10.1186/gb-2009-10-9-r100] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 08/21/2009] [Accepted: 09/22/2009] [Indexed: 11/29/2022] Open
Abstract
Over 600 LINE 1 elements are shown to be transcribed in humans; 400 of these are full-length elements in the reference genome. Background While LINE1 (L1) retroelements comprise nearly 20% of the human genome, the majority are thought to have been rendered transcriptionally inactive, due to either mutation or epigenetic suppression. How many L1 elements 'escape' these forms of repression and contribute to the transcriptome of human somatic cells? We have cloned out expressed sequence tags corresponding to the 5' and 3' flanks of L1 elements in order to characterize the population of elements that are being actively transcribed. We also examined expression of a select number of elements in different individuals. Results We isolated expressed sequence tags from human lymphoblastoid cell lines corresponding to 692 distinct L1 element sites, including 410 full-length elements. Four of the expression tagged sites corresponding to full-length elements from the human specific L1Hs subfamily were examined in European-American individuals and found to be differentially expressed in different family members. Conclusions A large number of different L1 element sites are expressed in human somatic tissues, and this expression varies among different individuals. Paradoxically, few elements were tagged at high frequency, indicating that the majority of expressed L1s are transcribed at low levels. Based on our preliminary expression studies of a limited number of elements in a single family, we predict a significant degree of inter-individual transcript-level polymorphism in this class of sequence.
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Affiliation(s)
- Sanjida H Rangwala
- Department of Genetics, University of Pennsylvania School of Medicine, Hamilton Walk, Philadelphia, Pennsylvania 19104, USA.
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Marchal JA, Acosta MJ, Bullejos M, de la Guardia RD, Sánchez A. Origin and spread of the SRY gene on the X and Y chromosomes of the rodent Microtus cabrerae: Role of L1 elements. Genomics 2008; 91:142-51. [DOI: 10.1016/j.ygeno.2007.10.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 10/15/2007] [Accepted: 10/19/2007] [Indexed: 11/30/2022]
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Xing J, Wang H, Belancio VP, Cordaux R, Deininger PL, Batzer MA. Emergence of primate genes by retrotransposon-mediated sequence transduction. Proc Natl Acad Sci U S A 2006; 103:17608-13. [PMID: 17101974 PMCID: PMC1693794 DOI: 10.1073/pnas.0603224103] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Indexed: 02/06/2023] Open
Abstract
Gene duplication is one of the most important mechanisms for creating new genes and generating genomic novelty. Retrotransposon-mediated sequence transduction (i.e., the process by which a retrotransposon carries flanking sequence during its mobilization) has been proposed as a gene duplication mechanism. L1 exon shuffling potential has been reported in cell culture assays, and two potential L1-mediated exon shuffling events have been identified in the genome. SVA is the youngest retrotransposon family in primates and is capable of 3' flanking sequence transduction during retrotransposition. In this study, we examined all of the full-length SVA elements in the human genome to assess the frequency and impact of SVA-mediated 3' sequence transduction. Our results showed that approximately 53 kb of genomic sequences have been duplicated by 143 different SVA-mediated transduction events. In particular, we identified one group of SVA elements that duplicated the entire AMAC gene three times in the human genome through SVA-mediated transduction events, which happened before the divergence of humans and African great apes. In addition to the original AMAC gene, the three transduced AMAC copies contain intact ORFs in the human genome, and at least two are actively transcribed in different human tissues. The duplication of entire genes and the creation of previously undescribed gene families through retrotransposon-mediated sequence transduction represent an important mechanism by which mobile elements impact their host genomes.
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Affiliation(s)
- Jinchuan Xing
- Department of Biological Sciences, Biological Computation and Visualization Center, Center for BioModular Multi-Scale Systems, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803; and
| | - Hui Wang
- Department of Biological Sciences, Biological Computation and Visualization Center, Center for BioModular Multi-Scale Systems, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803; and
| | - Victoria P. Belancio
- Tulane Cancer Center SL-66, Department of Environmental Health Sciences, Tulane University Health Sciences Center, New Orleans, LA 70112
| | - Richard Cordaux
- Department of Biological Sciences, Biological Computation and Visualization Center, Center for BioModular Multi-Scale Systems, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803; and
| | - Prescott L. Deininger
- Tulane Cancer Center SL-66, Department of Environmental Health Sciences, Tulane University Health Sciences Center, New Orleans, LA 70112
| | - Mark A. Batzer
- Department of Biological Sciences, Biological Computation and Visualization Center, Center for BioModular Multi-Scale Systems, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803; and
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Abstract
Small nucleolar RNAs (snoRNAs) of the H/ACA box and C/D box categories guide the pseudouridylation and the 2′-O-ribose methylation of ribosomal RNAs by forming short duplexes with their target. Similarly, small Cajal body–specific RNAs (scaRNAs) guide modifications of spliceosomal RNAs. The vast majority of vertebrate sno/scaRNAs are located in introns of genes transcribed by RNA polymerase II and processed by exonucleolytic trimming after splicing. A bioinformatic search for orthologues of human sno/scaRNAs in sequenced mammalian genomes reveals the presence of species- or lineage-specific sno/scaRNA retroposons (sno/scaRTs) characterized by an A-rich tail and an ∼14-bp target site duplication that corresponds to their insertion site, as determined by interspecific genomic alignments. Three classes of snoRTs are defined based on the extent of intron and exon sequences from the snoRNA parental host gene they contain. SnoRTs frequently insert in gene introns in the sense orientation at genomic hot spots shared with other genetic mobile elements. Previously characterized human snoRNAs are encoded in retroposons whose parental copies can be identified by phylogenic analysis, showing that snoRTs can be faithfully processed. These results identify snoRNAs as a new family of mobile genetic elements. The insertion of new snoRNA copies might constitute a safeguard mechanism by which the biological activity of snoRNAs is maintained in spite of the risk of mutations in the parental copy. I furthermore propose that retroposition followed by genetic drift is a mechanism that increased snoRNA diversity during vertebrate evolution to eventually acquire new RNA-modification functions. Large parts of vertebrate genomes are made of repeated sequences that were first considered to be junk DNA, but are now recognized as important actors in genome evolution. Most are genetic mobile elements that can gain additional genomic copies by a copy-and-paste mechanism involving an RNA intermediate. One class, the L1 elements, encodes two proteins required for its integration at new sites. Others, like primate Alu elements, hijack the L1 machinery for their mobilization, and are thus referred to as nonautonomous. In this article, Weber describes a new class of vertebrate nonautonomous mobile elements derived from small nucleolar RNAs (snoRNAs). These nonprotein-coding RNAs are encoded in gene introns and are involved in chemical modifications of selected bases of ribosomal RNAs. The article shows that new snoRNA copies were generated in vertebrate genomes via the copy-and-paste mechanism. Many of them are species-specific, and their insertion point was precisely determined by alignment with the corresponding genomic portion from a neighbour species. The mobilization of snoRNA gene sequences might ensure the presence of a functional copy when the parental one becomes invalidated by mutations. Moreover, such copies could evolve on their own to acquire the capacity of guiding new modifications of ribosomal RNAs.
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Affiliation(s)
- Michel J Weber
- Laboratoire de Biologie Moléculaire Eucaryote, CNRS/Université de Toulouse-Paul Sabatier, Toulouse, France.
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Ichiyanagi K, Okada N. Genomic alterations upon integration of zebrafish L1 elements revealed by the TANT method. Gene 2006; 383:108-16. [PMID: 17049188 DOI: 10.1016/j.gene.2006.07.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Revised: 07/07/2006] [Accepted: 07/07/2006] [Indexed: 11/25/2022]
Abstract
Transposable elements, or transposons, constitute substantial portions of eukaryotic genomes and have contributed to the diversity and functions of the genomes. Bioinformatic analysis of target junctions of genomic transposon copies can provide insights into their mobility mechanisms and consequent genomic alterations, but definitive identification of the target junctions remains difficult despite the steady accumulation of genomic sequence information. To overcome this difficulty, we recently developed a method termed "the target analysis of nested transposons" (TANT), which anatomizes junction features of numerous genomic copies of transposons that reside within other transposons. Whereas the mammalian long interspersed nuclear element (LINE)-1 (L1), a retrotransposon, has been proposed to make a considerable impact on host genomes, the mobility and impact of non-mammalian L1s are poorly understood. In the present study, we analyzed genomic copies of zebrafish L1 elements by using the TANT method. Some copies exhibited the features of integration that are similar to those of mammalian L1s. The zebrafish L1 retrotransposition reaction, however, frequently truncated the target-site DNA by up to 0.6 kb and produced a new sequence at LINE-target junctions. Moreover, our data suggest that L1 retrotransposition can be used to repair double-strand DNA breaks (DSBs). These results imply that L1s have had considerable impact on the evolution of the zebrafish genome.
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Affiliation(s)
- Kenji Ichiyanagi
- Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259-B21 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
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Evgen'ev MB, Arkhipova IR. Penelope-like elements – a new class of retroelements: distribution, function and possible evolutionary significance. Cytogenet Genome Res 2005; 110:510-21. [PMID: 16093704 DOI: 10.1159/000084984] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2003] [Accepted: 01/27/2004] [Indexed: 11/19/2022] Open
Abstract
Here we describe a new class of retroelements termed PLE (Penelope-like elements). The only transpositionally active representative of this lineage found so far has been isolated from Drosophila virilis. This element, Penelope, is responsible for the hybrid dysgenesis syndrome in this species, characterized by simultaneous mobilization of several unrelated TE families in the progeny of dysgenic crosses. Several lines of evidence favor the hypothesis of recent Penelope invasion into D. virilis. Moreover, when D. virilisPenelope was introduced by P element-mediated transformation into the genome of D. melanogaster, it underwent extensive amplification in the new host and induced several traits of the dysgenesis syndrome, including gonadal atrophy and numerous mutations. The single ORF encoded by PLE consists of two principal domains: reverse transcriptase (RT) and endonuclease (EN), which is similar to GIY-YIG intron-encoded endonucleases. With the appearance of a large number of PLEs in genome databases from diverse eukaryotes, including amoebae, fungi, cnidarians, rotifers, flatworms, roundworms, fish, amphibia, and reptilia, it becomes possible to resolve their phylogenetic relationships with other RT groups with a greater degree of confidence. On the basis of their peculiar structural features, distinct phylogenetic placement, and structure of transcripts, we conclude that PLE constitute a novel class of eukaryotic retroelements, different from non-LTR and LTR retrotransposons.
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Affiliation(s)
- M B Evgen'ev
- Engelhardt Institute of Molecular Biology, Moscow, Russia.
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Han JS, Boeke JD. LINE-1 retrotransposons: Modulators of quantity and quality of mammalian gene expression? Bioessays 2005; 27:775-84. [PMID: 16015595 DOI: 10.1002/bies.20257] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
LINE-1 (L1) retrotransposons are replicating repetitive elements that, by mass, are the most-abundant sequences in the human genome. Over one-third of mammalian genomes are the result, directly or indirectly, of L1 retrotransposition. L1 encodes two proteins: ORF1, an RNA-binding protein, and ORF2, an endonuclease/reverse transcriptase. Both proteins are required for L1 mobilization. Apart from the obvious function of self-replication, it is not clear what other roles, if any, L1 plays within its host. The sheer magnitude of L1 sequences in our genome has fueled speculation that over evolutionary time L1 insertions may structurally modify endogenous genes and regulate gene expression. Here we provide a review of L1 replication and its potential functional consequences.
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Affiliation(s)
- Jeffrey S Han
- Department of Molecular Biology and Genetics and High Throughput Biology Center, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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