1
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Zuo B, Nneji LM, Sun YB. Comparative genomics reveals insights into anuran genome size evolution. BMC Genomics 2023; 24:379. [PMID: 37415107 DOI: 10.1186/s12864-023-09499-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 06/30/2023] [Indexed: 07/08/2023] Open
Abstract
BACKGROUND Amphibians, particularly anurans, display an enormous variation in genome size. Due to the unavailability of whole genome datasets in the past, the genomic elements and evolutionary causes of anuran genome size variation are poorly understood. To address this, we analyzed whole-genome sequences of 14 anuran species ranging in size from 1.1 to 6.8 Gb. By annotating multiple genomic elements, we investigated the genomic correlates of anuran genome size variation and further examined whether the genome size relates to habitat types. RESULTS Our results showed that intron expansions or contraction and Transposable Elements (TEs) diversity do not contribute significantly to genome size variation. However, the recent accumulation of transposable elements (TEs) and the lack of deletion of ancient TEs primarily accounted for the evolution of anuran genome sizes. Our study showed that the abundance and density of simple repeat sequences positively correlate with genome size. Ancestral state reconstruction revealed that genome size exhibits a taxon-specific pattern of evolution, with families Bufonidae and Pipidae experiencing extreme genome expansion and contraction events, respectively. Our result showed no relationship between genome size and habitat types, although large genome-sized species are predominantly found in humid habitats. CONCLUSIONS Overall, our study identified the genomic element and their evolutionary dynamics accounting for anuran genome size variation, thus paving a path to a greater understanding of the size evolution of the genome in amphibians.
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Affiliation(s)
- Bin Zuo
- Ministry of Education Key Laboratory for Transboundary Ecosecurity of Southwest China, Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University, Kunming, Yunnan, 650504, China
| | - Lotanna Micah Nneji
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08544, USA
| | - Yan-Bo Sun
- Ministry of Education Key Laboratory for Transboundary Ecosecurity of Southwest China, Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University, Kunming, Yunnan, 650504, China.
- Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Kunming, 650091, China.
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2
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Di Stefano LH, Saba LJ, Oghbaie M, Jiang H, McKerrow W, Benitez-Guijarro M, Taylor MS, LaCava J. Affinity-Based Interactome Analysis of Endogenous LINE-1 Macromolecules. Methods Mol Biol 2023; 2607:215-256. [PMID: 36449166 DOI: 10.1007/978-1-0716-2883-6_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
During their proliferation and the host's concomitant attempts to suppress it, LINE-1 (L1) retrotransposons give rise to a collection of heterogeneous ribonucleoproteins (RNPs); their protein and RNA compositions remain poorly defined. The constituents of L1-associated macromolecules can differ depending on numerous factors, including, for example, position within the L1 life cycle, whether the macromolecule is productive or under suppression, and the cell type within which the proliferation is occurring. This chapter describes techniques that aid the capture and characterization of protein and RNA components of L1 macromolecules from tissues that natively express them. The protocols described have been applied to embryonal carcinoma cell lines that are popular model systems for L1 molecular biology (e.g., N2102Ep, NTERA-2, and PA-1 cells), as well as colorectal cancer tissues. N2102Ep cells are given as the use case for this chapter; the protocols should be applicable to essentially any tissue exhibiting endogenous L1 expression with minor modifications.
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3
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Del Valle RP, McLaughlin RN. Stealing genes and facing consequences. Science 2022; 378:356-357. [DOI: 10.1126/science.ade4942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The human genome contains a domesticated viral envelope gene with antiviral activity
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4
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Dong X, Zhang C, Peng Y, Zhang HX, Shi LD, Wei G, Hubert CRJ, Wang Y, Greening C. Phylogenetically and catabolically diverse diazotrophs reside in deep-sea cold seep sediments. Nat Commun 2022; 13:4885. [PMID: 35985998 PMCID: PMC9391474 DOI: 10.1038/s41467-022-32503-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 08/03/2022] [Indexed: 11/16/2022] Open
Abstract
Microbially mediated nitrogen cycling in carbon-dominated cold seep environments remains poorly understood. So far anaerobic methanotrophic archaea (ANME-2) and their sulfate-reducing bacterial partners (SEEP-SRB1 clade) have been identified as diazotrophs in deep sea cold seep sediments. However, it is unclear whether other microbial groups can perform nitrogen fixation in such ecosystems. To fill this gap, we analyzed 61 metagenomes, 1428 metagenome-assembled genomes, and six metatranscriptomes derived from 11 globally distributed cold seeps. These sediments contain phylogenetically diverse nitrogenase genes corresponding to an expanded diversity of diazotrophic lineages. Diverse catabolic pathways were predicted to provide ATP for nitrogen fixation, suggesting diazotrophy in cold seeps is not necessarily associated with sulfate-dependent anaerobic oxidation of methane. Nitrogen fixation genes among various diazotrophic groups in cold seeps were inferred to be genetically mobile and subject to purifying selection. Our findings extend the capacity for diazotrophy to five candidate phyla (Altarchaeia, Omnitrophota, FCPU426, Caldatribacteriota and UBA6262), and suggest that cold seep diazotrophs might contribute substantially to the global nitrogen balance. Microbial nitrogen fixation could be important in the deep sea. Here the authors investigate metagenomes and metatranscriptomes of diazotrophs from deep sea cold seep sediments, reveal greater phylogenetic and functional diversity than hitherto known.
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5
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DeRosa H, Richter T, Wilkinson C, Hunter RG. Bridging the Gap Between Environmental Adversity and Neuropsychiatric Disorders: The Role of Transposable Elements. Front Genet 2022; 13:813510. [PMID: 35711940 PMCID: PMC9196244 DOI: 10.3389/fgene.2022.813510] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 04/13/2022] [Indexed: 12/21/2022] Open
Abstract
Long regarded as “junk DNA,” transposable elements (TEs) have recently garnered much attention for their role in promoting genetic diversity and plasticity. While many processes involved in mammalian development require TE activity, deleterious TE insertions are a hallmark of several psychiatric disorders. Moreover, stressful events including exposure to gestational infection and trauma, are major risk factors for developing psychiatric illnesses. Here, we will provide evidence demonstrating the intersection of stressful events, atypical TE expression, and their epigenetic regulation, which may explain how neuropsychiatric phenotypes manifest. In this way, TEs may be the “bridge” between environmental perturbations and psychopathology.
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Affiliation(s)
- Holly DeRosa
- Psychology Department, Developmental Brain Sciences Program, College of Liberal Arts, University of Massachusetts Boston, Boston, MA, United States
| | - Troy Richter
- Psychology Department, Developmental Brain Sciences Program, College of Liberal Arts, University of Massachusetts Boston, Boston, MA, United States
| | - Cooper Wilkinson
- Psychology Department, Developmental Brain Sciences Program, College of Liberal Arts, University of Massachusetts Boston, Boston, MA, United States
| | - Richard G Hunter
- Psychology Department, Developmental Brain Sciences Program, College of Liberal Arts, University of Massachusetts Boston, Boston, MA, United States
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6
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Aydın F, Özer G, Alkan M, Çakır İ. Genetic diversity and population structure of Saccharomyces cerevisiae isolated from Turkish sourdough by iPBS-retrotransposons markers. Arch Microbiol 2022; 204:693. [PMCID: PMC9640837 DOI: 10.1007/s00203-022-03313-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 09/30/2022] [Accepted: 10/29/2022] [Indexed: 11/10/2022]
Abstract
Molecular DNA markers are valuable tools for analyzing genetic variation among yeast from different populations to reveal the genetically different autochthonous strains. In this study, we employed inter-primer binding site (iPBS) retrotransposon polymorphism to assess the genetic variation and population structure of 96 Saccharomyces cerevisiae isolates from four different regions in Turkey. The nine selected iPBS primers amplified 102 reproducible and scorable bands, of which 95.10% were polymorphic with an average of 10.78 polymorphic fragments per primer. The average polymorphism information content and the resolving power were 0.26–3.58, respectively. Analysis of molecular variance (AMOVA) revealed significant (P < 0.001) genetic differences within populations (88%) and between populations (12%). The unweighted pair group mean with arithmetic (UPGMA) dendrogram grouped 96 S. cerevisiae strains into two main clusters, where the highest probability of the data elucidating the population structure was obtained at ΔK = 2. There was not an obvious genetic discrimination of the populations according to geographical regions on UPGMA, supported by principal coordinate analysis. However, the individuals of the closer provinces in each population were more likely to group together or closely. The results indicate that iPBS polymorphism is a useful tool to reveal the genetically diverse autochthonous S. cerevisiae strains that may be important for the production of sourdough or baked goods.
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Affiliation(s)
- Furkan Aydın
- Department of Food Engineering, Faculty of Engineering, Aksaray University, 68100 Aksaray, Turkey
| | - Göksel Özer
- Department of Plant Protection, Faculty of Agriculture, Bolu Abant Izzet Baysal University, 14030 Bolu, Turkey
| | - Mehtap Alkan
- Department of Plant Protection, Faculty of Agriculture, Bolu Abant Izzet Baysal University, 14030 Bolu, Turkey
| | - İbrahim Çakır
- Department of Food Engineering, Faculty of Engineering, Bolu Abant Izzet Baysal University, 14030 Bolu, Turkey
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7
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Liu G, Jiang H, Sun W, Zhang J, Chen D, Murchie AIH. The function of twister ribozyme variants in non-LTR retrotransposition in Schistosoma mansoni. Nucleic Acids Res 2021; 49:10573-10588. [PMID: 34551436 PMCID: PMC8501958 DOI: 10.1093/nar/gkab818] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 08/23/2021] [Accepted: 09/08/2021] [Indexed: 12/13/2022] Open
Abstract
The twister ribozyme is widely distributed over numerous organisms and is especially abundant in Schistosoma mansoni, but has no confirmed biological function. Of the 17 non-LTR retrotransposons known in S. mansoni, none have thus far been associated with ribozymes. Here we report the identification of novel twister variant (T-variant) ribozymes and their function in S. mansoni non-LTR retrotransposition. We show that T-variant ribozymes are located at the 5′ end of Perere-3 non-LTR retrotransposons in the S. mansoni genome. T-variant ribozymes were demonstrated to be catalytically active in vitro. In reporter constructs, T-variants were shown to cleave in vivo, and cleavage of T-variants was sufficient for the translation of downstream reporter genes. Our analysis shows that the T-variants and Perere-3 are transcribed together. Target site duplications (TSDs); markers of target-primed reverse transcription (TPRT) and footmarks of retrotransposition, are located adjacent to the T-variant cleavage site and suggest that T-variant cleavage has taken place inS. mansoni. Sequence heterogeneity in the TSDs indicates that Perere-3 retrotransposition is not site-specific. The TSD sequences contribute to the 5′ end of the terminal ribozyme helix (P1 stem). Based on these results we conclude that T-variants have a functional role in Perere-3 retrotransposition.
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Affiliation(s)
- Getong Liu
- Fudan University Pudong Medical Center, and Institutes of Biomedical Sciences, Shanghai Medical College, Key Laboratory of Medical Epigenetics and Metabolism, Fudan University, Shanghai 200032, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Hengyi Jiang
- Fudan University Pudong Medical Center, and Institutes of Biomedical Sciences, Shanghai Medical College, Key Laboratory of Medical Epigenetics and Metabolism, Fudan University, Shanghai 200032, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Wenxia Sun
- Fudan University Pudong Medical Center, and Institutes of Biomedical Sciences, Shanghai Medical College, Key Laboratory of Medical Epigenetics and Metabolism, Fudan University, Shanghai 200032, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Jun Zhang
- Fudan University Pudong Medical Center, and Institutes of Biomedical Sciences, Shanghai Medical College, Key Laboratory of Medical Epigenetics and Metabolism, Fudan University, Shanghai 200032, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Dongrong Chen
- Fudan University Pudong Medical Center, and Institutes of Biomedical Sciences, Shanghai Medical College, Key Laboratory of Medical Epigenetics and Metabolism, Fudan University, Shanghai 200032, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Alastair I H Murchie
- Fudan University Pudong Medical Center, and Institutes of Biomedical Sciences, Shanghai Medical College, Key Laboratory of Medical Epigenetics and Metabolism, Fudan University, Shanghai 200032, China.,Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
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8
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Bello-Morales R, Andreu S, Ripa I, López-Guerrero JA. HSV-1 and Endogenous Retroviruses as Risk Factors in Demyelination. Int J Mol Sci 2021; 22:ijms22115738. [PMID: 34072259 PMCID: PMC8199333 DOI: 10.3390/ijms22115738] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 12/19/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1) is a neurotropic alphaherpesvirus that can infect the peripheral and central nervous systems, and it has been implicated in demyelinating and neurodegenerative processes. Transposable elements (TEs) are DNA sequences that can move from one genomic location to another. TEs have been linked to several diseases affecting the central nervous system (CNS), including multiple sclerosis (MS), a demyelinating disease of unknown etiology influenced by genetic and environmental factors. Exogenous viral transactivators may activate certain retrotransposons or class I TEs. In this context, several herpesviruses have been linked to MS, and one of them, HSV-1, might act as a risk factor by mediating processes such as molecular mimicry, remyelination, and activity of endogenous retroviruses (ERVs). Several herpesviruses have been involved in the regulation of human ERVs (HERVs), and HSV-1 in particular can modulate HERVs in cells involved in MS pathogenesis. This review exposes current knowledge about the relationship between HSV-1 and human ERVs, focusing on their contribution as a risk factor for MS.
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Affiliation(s)
- Raquel Bello-Morales
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (I.R.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
- Correspondence:
| | - Sabina Andreu
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (I.R.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
| | - Inés Ripa
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (I.R.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
| | - José Antonio López-Guerrero
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (I.R.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
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9
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Chen D, Cremona MA, Qi Z, Mitra RD, Chiaromonte F, Makova KD. Human L1 Transposition Dynamics Unraveled with Functional Data Analysis. Mol Biol Evol 2021; 37:3576-3600. [PMID: 32722770 DOI: 10.1093/molbev/msaa194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Long INterspersed Elements-1 (L1s) constitute >17% of the human genome and still actively transpose in it. Characterizing L1 transposition across the genome is critical for understanding genome evolution and somatic mutations. However, to date, L1 insertion and fixation patterns have not been studied comprehensively. To fill this gap, we investigated three genome-wide data sets of L1s that integrated at different evolutionary times: 17,037 de novo L1s (from an L1 insertion cell-line experiment conducted in-house), and 1,212 polymorphic and 1,205 human-specific L1s (from public databases). We characterized 49 genomic features-proxying chromatin accessibility, transcriptional activity, replication, recombination, etc.-in the ±50 kb flanks of these elements. These features were contrasted between the three L1 data sets and L1-free regions using state-of-the-art Functional Data Analysis statistical methods, which treat high-resolution data as mathematical functions. Our results indicate that de novo, polymorphic, and human-specific L1s are surrounded by different genomic features acting at specific locations and scales. This led to an integrative model of L1 transposition, according to which L1s preferentially integrate into open-chromatin regions enriched in non-B DNA motifs, whereas they are fixed in regions largely free of purifying selection-depleted of genes and noncoding most conserved elements. Intriguingly, our results suggest that L1 insertions modify local genomic landscape by extending CpG methylation and increasing mononucleotide microsatellite density. Altogether, our findings substantially facilitate understanding of L1 integration and fixation preferences, pave the way for uncovering their role in aging and cancer, and inform their use as mutagenesis tools in genetic studies.
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Affiliation(s)
- Di Chen
- Intercollege Graduate Degree Program in Genetics, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA
| | - Marzia A Cremona
- Department of Statistics, The Pennsylvania State University, University Park, PA.,Department of Operations and Decision Systems, Université Laval, Québec, Canada
| | - Zongtai Qi
- Department of Genetics and Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO
| | - Robi D Mitra
- Department of Genetics and Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO
| | - Francesca Chiaromonte
- Department of Statistics, The Pennsylvania State University, University Park, PA.,EMbeDS, Sant'Anna School of Advanced Studies, Pisa, Italy.,The Huck Institutes of the Life Sciences, Center for Medical Genomics, The Pennsylvania State University, University Park, PA
| | - Kateryna D Makova
- The Huck Institutes of the Life Sciences, Center for Medical Genomics, The Pennsylvania State University, University Park, PA.,Department of Biology, The Pennsylvania State University, University Park, PA
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10
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Waldern JM, Smith D, Piazza CL, Bailey EJ, Schiraldi NJ, Nemati R, Fabris D, Belfort M, Novikova O. Methylation of rRNA as a host defense against rampant group II intron retrotransposition. Mob DNA 2021; 12:9. [PMID: 33678171 PMCID: PMC7938551 DOI: 10.1186/s13100-021-00237-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 02/22/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Group II introns are mobile retroelements, capable of invading new sites in DNA. They are self-splicing ribozymes that complex with an intron-encoded protein to form a ribonucleoprotein that targets DNA after splicing. These molecules can invade DNA site-specifically, through a process known as retrohoming, or can invade ectopic sites through retrotransposition. Retrotransposition, in particular, can be strongly influenced by both environmental and cellular factors. RESULTS To investigate host factors that influence retrotransposition, we performed random insertional mutagenesis using the ISS1 transposon to generate a library of over 1000 mutants in Lactococcus lactis, the native host of the Ll.LtrB group II intron. By screening this library, we identified 92 mutants with increased retrotransposition frequencies (RTP-ups). We found that mutations in amino acid transport and metabolism tended to have increased retrotransposition frequencies. We further explored a subset of these RTP-up mutants, the most striking of which is a mutant in the ribosomal RNA methyltransferase rlmH, which exhibited a reproducible 20-fold increase in retrotransposition frequency. In vitro and in vivo experiments revealed that ribosomes in the rlmH mutant were defective in the m3Ψ modification and exhibited reduced binding to the intron RNA. CONCLUSIONS Taken together, our results reinforce the importance of the native host organism in regulating group II intron retrotransposition. In particular, the evidence from the rlmH mutant suggests a role for ribosome modification in limiting rampant retrotransposition.
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Affiliation(s)
- Justin M. Waldern
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
- Current address: Department of Biology, University of North Carolina, 270 Bell Tower Drive, Chapel Hill, NC 27599 USA
| | - Dorie Smith
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
| | - Carol Lyn Piazza
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
| | - E. Jake Bailey
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
| | - Nicholas J. Schiraldi
- Academic and Research Computing Center, Information Technology Services, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
| | - Reza Nemati
- Department of Chemistry, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
- Current address: Biogen, 125 Broadway, Cambridge, MA 02142 USA
| | - Dan Fabris
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
- Department of Chemistry, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
- Current address: Department of Chemistry, University of Connecticut, 55 N. Eagleville Road, Storrs, CT 06268 USA
| | - Marlene Belfort
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
- Department of Biomedical Sciences, School of Public Health, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
| | - Olga Novikova
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
- Current address: Biology Department, SUNY Buffalo State College, 1300 Elmwood Avenue, Buffalo, NY 14222 USA
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11
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Mat Razali N, Hisham SN, Kumar IS, Shukla RN, Lee M, Abu Bakar MF, Nadarajah K. Comparative Genomics: Insights on the Pathogenicity and Lifestyle of Rhizoctonia solani. Int J Mol Sci 2021; 22:ijms22042183. [PMID: 33671736 PMCID: PMC7926851 DOI: 10.3390/ijms22042183] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 02/06/2021] [Accepted: 02/15/2021] [Indexed: 12/17/2022] Open
Abstract
Proper management of agricultural disease is important to ensure sustainable food security. Staple food crops like rice, wheat, cereals, and other cash crops hold great export value for countries. Ensuring proper supply is critical; hence any biotic or abiotic factors contributing to the shortfall in yield of these crops should be alleviated. Rhizoctonia solani is a major biotic factor that results in yield losses in many agriculturally important crops. This paper focuses on genome informatics of our Malaysian Draft R. solani AG1-IA, and the comparative genomics (inter- and intra- AG) with four AGs including China AG1-IA (AG1-IA_KB317705.1), AG1-IB, AG3, and AG8. The genomic content of repeat elements, transposable elements (TEs), syntenic genomic blocks, functions of protein-coding genes as well as core orthologous genic information that underlies R. solani’s pathogenicity strategy were investigated. Our analyses show that all studied AGs have low content and varying profiles of TEs. All AGs were dominant for Class I TE, much like other basidiomycete pathogens. All AGs demonstrate dominance in Glycoside Hydrolase protein-coding gene assignments suggesting its importance in infiltration and infection of host. Our profiling also provides a basis for further investigation on lack of correlation observed between number of pathogenicity and enzyme-related genes with host range. Despite being grouped within the same AG with China AG1-IA, our Draft AG1-IA exhibits differences in terms of protein-coding gene proportions and classifications. This implies that strains from similar AG do not necessarily have to retain similar proportions and classification of TE but must have the necessary arsenal to enable successful infiltration and colonization of host. In a larger perspective, all the studied AGs essentially share core genes that are generally involved in adhesion, penetration, and host colonization. However, the different infiltration strategies will depend on the level of host resilience where this is clearly exhibited by the gene sets encoded for the process of infiltration, infection, and protection from host.
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Affiliation(s)
- Nurhani Mat Razali
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (N.M.R.); (S.N.H.); (I.S.K.)
| | - Siti Norvahida Hisham
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (N.M.R.); (S.N.H.); (I.S.K.)
| | - Ilakiya Sharanee Kumar
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (N.M.R.); (S.N.H.); (I.S.K.)
| | - Rohit Nandan Shukla
- Bionivid Technology Pte Ltd., 209, 4th Cross Rd, B Channasandra, East of NGEF Layout, Kasturi Nagar, Bengaluru 560043, Karnataka, India;
| | - Melvin Lee
- Codon Genomics Sdn. Bhd., No 26, Jalan Dutamas 7 Taman Dutamas Balakong, Seri Kembangan 43200, Selangor, Malaysia;
| | | | - Kalaivani Nadarajah
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (N.M.R.); (S.N.H.); (I.S.K.)
- Correspondence:
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12
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Etchegaray E, Naville M, Volff JN, Haftek-Terreau Z. Transposable element-derived sequences in vertebrate development. Mob DNA 2021; 12:1. [PMID: 33407840 PMCID: PMC7786948 DOI: 10.1186/s13100-020-00229-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 12/15/2020] [Indexed: 12/14/2022] Open
Abstract
Transposable elements (TEs) are major components of all vertebrate genomes that can cause deleterious insertions and genomic instability. However, depending on the specific genomic context of their insertion site, TE sequences can sometimes get positively selected, leading to what are called "exaptation" events. TE sequence exaptation constitutes an important source of novelties for gene, genome and organism evolution, giving rise to new regulatory sequences, protein-coding exons/genes and non-coding RNAs, which can play various roles beneficial to the host. In this review, we focus on the development of vertebrates, which present many derived traits such as bones, adaptive immunity and a complex brain. We illustrate how TE-derived sequences have given rise to developmental innovations in vertebrates and how they thereby contributed to the evolutionary success of this lineage.
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Affiliation(s)
- Ema Etchegaray
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364, Lyon, France.
| | - Magali Naville
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364, Lyon, France
| | - Jean-Nicolas Volff
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364, Lyon, France
| | - Zofia Haftek-Terreau
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364, Lyon, France
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13
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R2 and Non-Site-Specific R2-Like Retrotransposons of the German Cockroach, Blattella germanica. Genes (Basel) 2020; 11:genes11101202. [PMID: 33076367 PMCID: PMC7650587 DOI: 10.3390/genes11101202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/10/2020] [Accepted: 10/12/2020] [Indexed: 11/17/2022] Open
Abstract
The structural and functional organization of the ribosomal RNA gene cluster and the full-length R2 non-LTR retrotransposon (integrated into a specific site of 28S ribosomal RNA genes) of the German cockroach, Blattella germanica, is described. A partial sequence of the R2 retrotransposon of the cockroach Rhyparobia maderae is also analyzed. The analysis of previously published next-generation sequencing data from the B. germanica genome reveals a new type of retrotransposon closely related to R2 retrotransposons but with a random distribution in the genome. Phylogenetic analysis reveals that these newly described retrotransposons form a separate clade. It is shown that proteins corresponding to the open reading frames of newly described retrotransposons exhibit unequal structural domains. Within these retrotransposons, a recombination event is described. New mechanism of transposition activity is discussed. The essential structural features of R2 retrotransposons are conserved in cockroaches and are typical of previously described R2 retrotransposons. However, the investigation of the number and frequency of 5′-truncated R2 retrotransposon insertion variants in eight B. germanica populations suggests recent mobile element activity. It is shown that the pattern of 5′-truncated R2 retrotransposon copies can be an informative molecular genetic marker for revealing genetic distances between insect populations.
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14
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Fernandez L, Peura S, Eiler A, Linz AM, McMahon KD, Bertilsson S. Diazotroph Genomes and Their Seasonal Dynamics in a Stratified Humic Bog Lake. Front Microbiol 2020; 11:1500. [PMID: 32714313 PMCID: PMC7341956 DOI: 10.3389/fmicb.2020.01500] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 06/09/2020] [Indexed: 12/28/2022] Open
Abstract
Aquatic N-fixation is generally associated with the growth and mass development of Cyanobacteria in nitrogen-deprived photic zones. However, sequenced genomes and environmental surveys suggest active aquatic N-fixation also by many non-cyanobacterial groups. Here, we revealed the seasonal variation and genomic diversity of potential N-fixers in a humic bog lake using metagenomic data and nif gene clusters analysis. Groups with diazotrophic operons were functionally divergent and included Cholorobi, Geobacter, Desulfobacterales, Methylococcales, and Acidobacteria. In addition to nifH (a gene that encodes the dinitrogenase reductase component of the molybdenum nitrogenase), we also identified sequences corresponding to vanadium and iron-only nitrogenase genes. Within the Chlorobi population, the nitrogenase (nifH) cluster was included in a well-structured retrotransposon. Furthermore, the presence of light-harvesting photosynthesis genes implies that anoxygenic photosynthesis may fuel nitrogen fixation under the prevailing low-irradiance conditions. The presence of rnf genes (related to the expression of H+/Na+-translocating ferredoxin: NAD+ oxidoreductase) in Methylococcales and Desulfobacterales suggests that other energy-generating processes may drive the costly N-fixation in the absence of photosynthesis. The highly reducing environment of the anoxic bottom layer of Trout Bog Lake may thus also provide a suitable niche for active N-fixers and primary producers. While future studies on the activity of these potential N-fixers are needed to clarify their role in freshwater nitrogen cycling, the metagenomic data presented here enabled an initial characterization of previously overlooked diazotrophs in freshwater biomes.
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Affiliation(s)
- Leyden Fernandez
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Sari Peura
- Department of Forest Mycology and Plant Pathology, Science for Life Laboratory, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Alexander Eiler
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.,Centre for Biogeochemistry in the Anthropocene, Department of Biosciences, Section for Aquatic Biology and Toxicology, University of Oslo, Oslo, Norway
| | - Alexandra M Linz
- Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, United States
| | - Katherine D McMahon
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States.,Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, United States
| | - Stefan Bertilsson
- Department of Ecology and Genetics, Limnology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.,Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
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15
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Maxwell PH. Diverse transposable element landscapes in pathogenic and nonpathogenic yeast models: the value of a comparative perspective. Mob DNA 2020; 11:16. [PMID: 32336995 PMCID: PMC7175516 DOI: 10.1186/s13100-020-00215-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/16/2020] [Indexed: 12/14/2022] Open
Abstract
Genomics and other large-scale analyses have drawn increasing attention to the potential impacts of transposable elements (TEs) on their host genomes. However, it remains challenging to transition from identifying potential roles to clearly demonstrating the level of impact TEs have on genome evolution and possible functions that they contribute to their host organisms. I summarize TE content and distribution in four well-characterized yeast model systems in this review: the pathogens Candida albicans and Cryptococcus neoformans, and the nonpathogenic species Saccharomyces cerevisiae and Schizosaccharomyces pombe. I compare and contrast their TE landscapes to their lifecycles, genomic features, as well as the presence and nature of RNA interference pathways in each species to highlight the valuable diversity represented by these models for functional studies of TEs. I then review the regulation and impacts of the Ty1 and Ty3 retrotransposons from Saccharomyces cerevisiae and Tf1 and Tf2 retrotransposons from Schizosaccharomyces pombe to emphasize parallels and distinctions between these well-studied elements. I propose that further characterization of TEs in the pathogenic yeasts would enable this set of four yeast species to become an excellent set of models for comparative functional studies to address outstanding questions about TE-host relationships.
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16
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Iwasaki WM, Kijima TE, Innan H. Population Genetics and Molecular Evolution of DNA Sequences in Transposable Elements. II. Accumulation of Variation and Evolution of a New Subfamily. Mol Biol Evol 2020; 37:355-364. [PMID: 31580443 DOI: 10.1093/molbev/msz220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In order to understand how DNA sequences of transposable elements (TEs) evolve, extensive simulations were carried out. We first used our previous model, in which the copy number of TEs is mainly controlled by selection against ectopic recombination. It was found that along a simulation run, the shape of phylogeny changes quite much, from monophyletic trees to dimorphic trees with two clusters. Our results demonstrated that the change of the phase is usually slow from a monomorphic phase to a dimorphic phase, accompanied with a growth of an internal branch by accumulation of variation between two types. Then, the phase immediately changes back to a monomorphic phase when one group gets extinct. Under this condition, monomorphic and dimorphic phases arise repeatedly, and it is very difficult to maintain two or more different types of TEs for a long time. Then, how a new subfamily can evolve? To solve this, we developed a new model, in which ectopic recombination is restricted between two types under some condition, for example, accumulation of mutations between them. Under this model, because selection works on the copy number of each types separately, two types can be maintained for a long time. As expected, our simulations demonstrated that a new type arises and persists quite stably, and that it will be recognized as a new subfamily followed by further accumulation of mutations. It is indicated that how ectopic recombination is regulated in a genome is an important factor for the evolution of a new subfamily.
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Affiliation(s)
- Watal M Iwasaki
- SOKENDAI, The Graduate University for Advanced Studies, Hayama, Kanagawa, Japan
| | - T E Kijima
- SOKENDAI, The Graduate University for Advanced Studies, Hayama, Kanagawa, Japan
| | - Hideki Innan
- SOKENDAI, The Graduate University for Advanced Studies, Hayama, Kanagawa, Japan
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17
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Abstract
In mammals and invertebrates, the proliferation of an invading transposable element (TE) is thought to be stopped by an insertion into a piRNA cluster. Here, we explore the dynamics of TE invasions under this trap model using computer simulations. We found that piRNA clusters confer a substantial benefit, effectively preventing extinction of host populations from a proliferation of deleterious TEs. TE invasions consist of three distinct phases: first, the TE amplifies within the population, next TE proliferation is stopped by segregating cluster insertions, and finally the TE is inactivated by fixation of a cluster insertion. Suppression by segregating cluster insertions is unstable and bursts of TE activity may yet occur. The transposition rate and the population size mostly influence the length of the phases but not the amount of TEs accumulating during an invasion. Solely, the size of piRNA clusters was identified as a major factor influencing TE abundance. We found that a single nonrecombining cluster is more efficient in stopping invasions than clusters distributed over several chromosomes. Recombination among cluster sites makes it necessary that each diploid carries, on the average, four cluster insertions to stop an invasion. Surprisingly, negative selection in a model with piRNA clusters can lead to a novel equilibrium state, where TE copy numbers remain stable despite only some individuals in a population carrying a cluster insertion. In Drosophila melanogaster, the trap model accounts for the abundance of TEs produced in the germline but fails to predict the abundance of TEs produced in the soma.
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Affiliation(s)
- Robert Kofler
- Institut für Populationsgenetik, Vetmeduni Vienna, Wien, Austria
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18
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Horie M. Interactions among eukaryotes, retrotransposons and riboviruses: endogenous riboviral elements in eukaryotic genomes. Genes Genet Syst 2020; 94:253-267. [PMID: 31257309 DOI: 10.1266/ggs.18-00049] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Riboviruses are viruses that have RNA genomes and replicate only via RNA intermediates. Although they do not require a DNA phase for replication and do not encode reverse transcriptase, the presence of DNA forms of riboviral sequences in ribovirus-infected cells has been reported since the 1970s. Additionally, heritable ribovirus-derived sequences, called riboviral endogenous viral elements (EVEs), have been found in the genomes of many eukaryotes. These are now thought to be formed by the reverse transcription machineries of retrotransposons within eukaryotic genomes sometimes referred to as selfish elements. Surprisingly, some reverse-transcribed riboviral DNAs (including EVEs) provide physiological functions for their hosts, suggesting the occurrence of novel interactions among eukaryotic genomes, retrotransposons and riboviruses, and opening the door to new avenues of investigation. Here I review current knowledge on these triangular interactions, and discuss future directions in this field.
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Affiliation(s)
- Masayuki Horie
- Hakubi Center for Advanced Research, and Department of Virus Research, Institute for Frontier Life and Medical Sciences, Kyoto University
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19
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Adney EM, Ochmann MT, Sil S, Truong DM, Mita P, Wang X, Kahler DJ, Fenyö D, Holt LJ, Boeke JD. Comprehensive Scanning Mutagenesis of Human Retrotransposon LINE-1 Identifies Motifs Essential for Function. Genetics 2019; 213:1401-1414. [PMID: 31666291 PMCID: PMC6893370 DOI: 10.1534/genetics.119.302601] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Accepted: 10/22/2019] [Indexed: 12/19/2022] Open
Abstract
Long Interspersed Nuclear Element-1 (LINE-1, L1) is the only autonomous active transposable element in the human genome. The L1-encoded proteins ORF1p and ORF2p enable the element to jump from one locus to another via a "copy-and-paste" mechanism. ORF1p is an RNA-binding protein, and ORF2p has endonuclease and reverse transcriptase activities. The huge number of truncated L1 remnants in the human genome suggests that the host has likely evolved mechanisms to prevent full L1 replication, and thereby decrease the proliferation of active elements and reduce the mutagenic potential of L1. In turn, L1 appears to have a minimized length to increase the probability of successful full-length replication. This streamlining would be expected to lead to high information density. Here, we describe the construction and initial characterization of a library of 538 consecutive trialanine substitutions that scan along ORF1p and ORF2p to identify functionally important regions. In accordance with the streamlining hypothesis, retrotransposition was overall very sensitive to mutations in ORF1p and ORF2p; only 16% of trialanine mutants retained near-wild-type (WT) activity. All ORF1p mutants formed near-WT levels of mRNA transcripts and 75% formed near-WT levels of protein. Two ORF1p mutants presented a unique nucleolar-relocalization phenotype. Regions of ORF2p that are sensitive to mutagenesis but lack phylogenetic conservation were also identified. We provide comprehensive information on the regions most critical to retrotransposition. This resource will guide future studies of intermolecular interactions that form with RNA, proteins, and target DNA throughout the L1 life cycle.
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Affiliation(s)
- Emily M Adney
- Institute for Systems Genetics, NYU Langone Health, New York 10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York 10016
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Matthias T Ochmann
- Institute for Systems Genetics, NYU Langone Health, New York 10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York 10016
- Division of Medical Biotechnology, Paul Ehrlich Institute, Langen 63225, Germany
| | - Srinjoy Sil
- Institute for Systems Genetics, NYU Langone Health, New York 10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York 10016
| | - David M Truong
- Institute for Systems Genetics, NYU Langone Health, New York 10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York 10016
| | - Paolo Mita
- Institute for Systems Genetics, NYU Langone Health, New York 10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York 10016
| | - Xuya Wang
- Institute for Systems Genetics, NYU Langone Health, New York 10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York 10016
| | - David J Kahler
- High Throughput Biology Laboratory, NYU Langone Health, New York 10016
| | - David Fenyö
- Institute for Systems Genetics, NYU Langone Health, New York 10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York 10016
| | - Liam J Holt
- Institute for Systems Genetics, NYU Langone Health, New York 10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York 10016
| | - Jef D Boeke
- Institute for Systems Genetics, NYU Langone Health, New York 10016
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York 10016
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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20
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Wei Y, Bettedi L, Ting CY, Kim K, Zhang Y, Cai J, Lilly MA. The GATOR complex regulates an essential response to meiotic double-stranded breaks in Drosophila. eLife 2019; 8:e42149. [PMID: 31650955 PMCID: PMC6834368 DOI: 10.7554/elife.42149] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 10/13/2019] [Indexed: 01/18/2023] Open
Abstract
The TORC1 regulator GATOR1/SEACIT controls meiotic entry and early meiotic events in yeast. However, how metabolic pathways influence meiotic progression in metazoans remains poorly understood. Here we examine the role of the TORC1 regulators GATOR1 and GATOR2 in the response to meiotic double-stranded breaks (DSB) during Drosophila oogenesis. We find that in mutants of the GATOR2 component mio, meiotic DSBs trigger the constitutive downregulation of TORC1 activity and a permanent arrest in oocyte growth. Conversely, in GATOR1 mutants, high TORC1 activity results in the delayed repair of meiotic DSBs and the hyperactivation of p53. Unexpectedly, we found that GATOR1 inhibits retrotransposon expression in the presence of meiotic DSBs in a pathway that functions in parallel to p53. Thus, our studies have revealed a link between oocyte metabolism, the repair of meiotic DSBs and retrotransposon expression.
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Affiliation(s)
- Youheng Wei
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
- College of Bioscience and BiotechnologyYangzhou UniversityYangzhouChina
| | - Lucia Bettedi
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Chun-Yuan Ting
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Kuikwon Kim
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Yingbiao Zhang
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Jiadong Cai
- College of Bioscience and BiotechnologyYangzhou UniversityYangzhouChina
| | - Mary A Lilly
- Cell Biology and Neurobiology BranchNational Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
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21
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Saint-Leandre B, Nguyen SC, Levine MT. Diversification and collapse of a telomere elongation mechanism. Genome Res 2019; 29:920-931. [PMID: 31138619 PMCID: PMC6581046 DOI: 10.1101/gr.245001.118] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 05/14/2019] [Indexed: 12/18/2022]
Abstract
In most eukaryotes, telomerase counteracts chromosome erosion by adding repetitive sequence to terminal ends. Drosophila melanogaster instead relies on specialized retrotransposons that insert exclusively at telomeres. This exchange of goods between host and mobile element-wherein the mobile element provides an essential genome service and the host provides a hospitable niche for mobile element propagation-has been called a "genomic symbiosis." However, these telomere-specialized, jockey family retrotransposons may actually evolve to "selfishly" overreplicate in the genomes that they ostensibly serve. Under this model, we expect rapid diversification of telomere-specialized retrotransposon lineages and, possibly, the breakdown of this ostensibly symbiotic relationship. Here we report data consistent with both predictions. Searching the raw reads of the 15-Myr-old melanogaster species group, we generated de novo jockey retrotransposon consensus sequences and used phylogenetic tree-building to delineate four distinct telomere-associated lineages. Recurrent gains, losses, and replacements account for this retrotransposon lineage diversity. In Drosophila biarmipes, telomere-specialized elements have disappeared completely. De novo assembly of long reads and cytogenetics confirmed this species-specific collapse of retrotransposon-dependent telomere elongation. Instead, telomere-restricted satellite DNA and DNA transposon fragments occupy its terminal ends. We infer that D. biarmipes relies instead on a recombination-based mechanism conserved from yeast to flies to humans. Telomeric retrotransposon diversification and disappearance suggest that persistently "selfish" machinery shapes telomere elongation across Drosophila rather than completely domesticated, symbiotic mobile elements.
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Affiliation(s)
- Bastien Saint-Leandre
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.,Epigenetics Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Son C Nguyen
- Epigenetics Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.,Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Mia T Levine
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.,Epigenetics Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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22
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Gier S, Simon M, Nordström K, Khalifa S, Schulz MH, Schmitt MJ, Breinig F. Transcriptome Kinetics of Saccharomyces cerevisiae in Response to Viral Killer Toxin K1. Front Microbiol 2019; 10:1102. [PMID: 31156606 PMCID: PMC6531845 DOI: 10.3389/fmicb.2019.01102] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/30/2019] [Indexed: 11/29/2022] Open
Abstract
The K1 A/B toxin secreted by virus-infected Saccharomyces cerevisiae strains kills sensitive cells via disturbance of cytoplasmic membrane functions. Despite decades of research, the mechanisms underlying K1 toxicity and immunity have not been elucidated yet. In a novel approach, this study aimed to characterize transcriptome changes in K1-treated sensitive yeast cells in a time-dependent manner. Global transcriptional profiling revealed substantial cellular adaptations in target cells resulting in 1,189 differentially expressed genes in total. Killer toxin K1 induced oxidative, cell wall and hyperosmotic stress responses as well as rapid down-regulation of transcription and translation. Essential pathways regulating energy metabolism were also significantly affected by the toxin. Remarkably, a futile cycle of the osmolytes trehalose and glycogen was identified probably representing a critical feature of K1 intoxication. In silico analysis suggested several transcription factors involved in toxin-triggered signal transduction. The identified transcriptome changes provide valuable hints to illuminate the still unknown molecular events leading to K1 toxicity and immunity implicating an evolutionarily conserved response at least initially counteracting ionophoric toxin action.
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Affiliation(s)
- Stefanie Gier
- Department of Molecular and Cell Biology, Saarland University, Saarbrücken, Germany.,Center of Human and Molecular Biology (ZHMB), Saarland University, Saarbrücken, Germany
| | - Martin Simon
- Center of Human and Molecular Biology (ZHMB), Saarland University, Saarbrücken, Germany.,Molecular Cell Biology and Microbiology, University of Wuppertal, Wuppertal, Germany.,Molecular Cell Dynamics, Saarland University, Saarbrücken, Germany
| | - Karl Nordström
- Center of Human and Molecular Biology (ZHMB), Saarland University, Saarbrücken, Germany.,Department of Genetics/Epigenetics, Saarland University, Saarbrücken, Germany
| | - Salem Khalifa
- Cluster of Excellence "Multimodal Computing and Interaction", Max Planck Institute for Informatics, Saarland University, Saarbrücken, Germany
| | - Marcel H Schulz
- Cluster of Excellence "Multimodal Computing and Interaction", Max Planck Institute for Informatics, Saarland University, Saarbrücken, Germany
| | - Manfred J Schmitt
- Department of Molecular and Cell Biology, Saarland University, Saarbrücken, Germany.,Center of Human and Molecular Biology (ZHMB), Saarland University, Saarbrücken, Germany
| | - Frank Breinig
- Department of Molecular and Cell Biology, Saarland University, Saarbrücken, Germany.,Center of Human and Molecular Biology (ZHMB), Saarland University, Saarbrücken, Germany
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23
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LaCava J. RNA Binding Proteins as Regulators of Retrotransposon-Induced Exonization. Bioessays 2019; 41:e1800263. [DOI: 10.1002/bies.201800263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Indexed: 11/06/2022]
Affiliation(s)
- John LaCava
- Laboratory of Cellular and Structural Biology; The Rockefeller University; NY 10065 USA
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24
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Testing the retroelement invasion hypothesis for the emergence of the ancestral eukaryotic cell. Proc Natl Acad Sci U S A 2018; 115:12465-12470. [PMID: 30455297 PMCID: PMC6298092 DOI: 10.1073/pnas.1807709115] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Phylogenetic evidence suggests that the invasion and proliferation of retroelements, selfish mobile genetic elements that copy and paste themselves within a host genome, was one of the early evolutionary events in the emergence of eukaryotes. Here we test the effects of this event by determining the pressures retroelements exert on simple genomes. We transferred two retroelements, human LINE-1 and the bacterial group II intron Ll.LtrB, into bacteria, and find that both are functional and detrimental to growth. We find, surprisingly, that retroelement lethality and proliferation are enhanced by the ability to perform eukaryotic-like nonhomologous end-joining (NHEJ) DNA repair. We show that the only stable evolutionary consequence in simple cells is maintenance of retroelements in low numbers, suggesting how retrotransposition rates and costs in early eukaryotes could have been constrained to allow proliferation. Our results suggest that the interplay between NHEJ and retroelements may have played a fundamental and previously unappreciated role in facilitating the proliferation of retroelements, elements of which became the ancestors of the spliceosome components in eukaryotes.
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25
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Kruitwagen T, Chymkowitch P, Denoth-Lippuner A, Enserink J, Barral Y. Centromeres License the Mitotic Condensation of Yeast Chromosome Arms. Cell 2018; 175:780-795.e15. [PMID: 30318142 PMCID: PMC6197839 DOI: 10.1016/j.cell.2018.09.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 06/14/2018] [Accepted: 09/07/2018] [Indexed: 12/18/2022]
Abstract
During mitosis, chromatin condensation shapes chromosomes as separate, rigid, and compact sister chromatids to facilitate their segregation. Here, we show that, unlike wild-type yeast chromosomes, non-chromosomal DNA circles and chromosomes lacking a centromere fail to condense during mitosis. The centromere promotes chromosome condensation strictly in cis through recruiting the kinases Aurora B and Bub1, which trigger the autonomous condensation of the entire chromosome. Shugoshin and the deacetylase Hst2 facilitated spreading the condensation signal to the chromosome arms. Targeting Aurora B to DNA circles or centromere-ablated chromosomes or releasing Shugoshin from PP2A-dependent inhibition bypassed the centromere requirement for condensation and enhanced the mitotic stability of DNA circles. Our data indicate that yeast cells license the chromosome-autonomous condensation of their chromatin in a centromere-dependent manner, excluding from this process non-centromeric DNA and thereby inhibiting their propagation.
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Affiliation(s)
- Tom Kruitwagen
- Institute of Biochemistry, Biology Department, ETH Zurich, 8093 Zurich, Switzerland
| | - Pierre Chymkowitch
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | | | - Jorrit Enserink
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379 Oslo, Norway; Faculty of Medicine, Center for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Faculty of Mathematics and Natural Sciences, Department of Biosciences, University of Oslo, Norway
| | - Yves Barral
- Institute of Biochemistry, Biology Department, ETH Zurich, 8093 Zurich, Switzerland.
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26
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Babakhani S, Oloomi M. Transposons: the agents of antibiotic resistance in bacteria. J Basic Microbiol 2018; 58:905-917. [PMID: 30113080 DOI: 10.1002/jobm.201800204] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/08/2018] [Accepted: 07/31/2018] [Indexed: 12/29/2022]
Abstract
Transposons are a group of mobile genetic elements that are defined as a DNA sequence. Transposons can jump into different places of the genome; for this reason, they are called jumping genes. However, some transposons are always kept at the insertion site in the genome. Most transposons are inactivated and as a result, cannot move. Transposons are divided into two main groups: retrotransposons (class І) and DNA transposons (class ІІ). Retrotransposons are often found in eukaryotes. DNA transposons can be found in both eukaryotes and prokaryotes. The bacterial transposons belong to the DNA transposons and the Tn family, which are usually the carrier of additional genes for antibiotic resistance. Transposons can transfer from a plasmid to other plasmids or from a DNA chromosome to plasmid and vice versa that cause the transmission of antibiotic resistance genes in bacteria. The treatment of bacterial infectious diseases is difficult because of existing antibiotic resistance that part of this antibiotic resistance is caused by transposons. Bacterial infectious diseases are responsible for the increasing rise in world mortality rate. In this review, transposons and their roles have been studied in bacterial antibiotic resistance, in detail.
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Affiliation(s)
- Sajad Babakhani
- Department of Microbiology, North Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Mana Oloomi
- Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran
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27
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Choi K, Zhao X, Tock AJ, Lambing C, Underwood CJ, Hardcastle TJ, Serra H, Kim J, Cho HS, Kim J, Ziolkowski PA, Yelina NE, Hwang I, Martienssen RA, Henderson IR. Nucleosomes and DNA methylation shape meiotic DSB frequency in Arabidopsis thaliana transposons and gene regulatory regions. Genome Res 2018; 28:532-546. [PMID: 29530928 PMCID: PMC5880243 DOI: 10.1101/gr.225599.117] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 02/08/2018] [Indexed: 02/02/2023]
Abstract
Meiotic recombination initiates from DNA double-strand breaks (DSBs) generated by SPO11 topoisomerase-like complexes. Meiotic DSB frequency varies extensively along eukaryotic chromosomes, with hotspots controlled by chromatin and DNA sequence. To map meiotic DSBs throughout a plant genome, we purified and sequenced Arabidopsis thaliana SPO11-1-oligonucleotides. SPO11-1-oligos are elevated in gene promoters, terminators, and introns, which is driven by AT-sequence richness that excludes nucleosomes and allows SPO11-1 access. A positive relationship was observed between SPO11-1-oligos and crossovers genome-wide, although fine-scale correlations were weaker. This may reflect the influence of interhomolog polymorphism on crossover formation, downstream from DSB formation. Although H3K4me3 is enriched in proximity to SPO11-1-oligo hotspots at gene 5' ends, H3K4me3 levels do not correlate with DSBs. Repetitive transposons are thought to be recombination silenced during meiosis, to prevent nonallelic interactions and genome instability. Unexpectedly, we found high SPO11-1-oligo levels in nucleosome-depleted Helitron/Pogo/Tc1/Mariner DNA transposons, whereas retrotransposons were coldspots. High SPO11-1-oligo transposons are enriched within gene regulatory regions and in proximity to immunity genes, suggesting a role as recombination enhancers. As transposon mobility in plant genomes is restricted by DNA methylation, we used the met1 DNA methyltransferase mutant to investigate the role of heterochromatin in SPO11-1-oligo distributions. Epigenetic activation of meiotic DSBs in proximity to centromeres and transposons occurred in met1 mutants, coincident with reduced nucleosome occupancy, gain of transcription, and H3K4me3. Together, our work reveals a complex relationship between chromatin and meiotic DSBs within A. thaliana genes and transposons, with significance for the diversity and evolution of plant genomes.
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Affiliation(s)
- Kyuha Choi
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom;,Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Xiaohui Zhao
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Andrew J. Tock
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Christophe Lambing
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Charles J. Underwood
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom;,Howard Hughes Medical Institute–Gordon and Betty Moore Foundation, Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Thomas J. Hardcastle
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Heïdi Serra
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Juhyun Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Hyun Seob Cho
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Jaeil Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Piotr A. Ziolkowski
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Nataliya E. Yelina
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Ildoo Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Robert A. Martienssen
- Howard Hughes Medical Institute–Gordon and Betty Moore Foundation, Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Ian R. Henderson
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
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28
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Choi K, Zhao X, Tock AJ, Lambing C, Underwood CJ, Hardcastle TJ, Serra H, Kim J, Cho HS, Kim J, Ziolkowski PA, Yelina NE, Hwang I, Martienssen RA, Henderson IR. Nucleosomes and DNA methylation shape meiotic DSB frequency in Arabidopsis thaliana transposons and gene regulatory regions. Genome Res 2018. [PMID: 29530928 DOI: 10.1101/gr.225599.117.28] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Meiotic recombination initiates from DNA double-strand breaks (DSBs) generated by SPO11 topoisomerase-like complexes. Meiotic DSB frequency varies extensively along eukaryotic chromosomes, with hotspots controlled by chromatin and DNA sequence. To map meiotic DSBs throughout a plant genome, we purified and sequenced Arabidopsis thaliana SPO11-1-oligonucleotides. SPO11-1-oligos are elevated in gene promoters, terminators, and introns, which is driven by AT-sequence richness that excludes nucleosomes and allows SPO11-1 access. A positive relationship was observed between SPO11-1-oligos and crossovers genome-wide, although fine-scale correlations were weaker. This may reflect the influence of interhomolog polymorphism on crossover formation, downstream from DSB formation. Although H3K4me3 is enriched in proximity to SPO11-1-oligo hotspots at gene 5' ends, H3K4me3 levels do not correlate with DSBs. Repetitive transposons are thought to be recombination silenced during meiosis, to prevent nonallelic interactions and genome instability. Unexpectedly, we found high SPO11-1-oligo levels in nucleosome-depleted Helitron/Pogo/Tc1/Mariner DNA transposons, whereas retrotransposons were coldspots. High SPO11-1-oligo transposons are enriched within gene regulatory regions and in proximity to immunity genes, suggesting a role as recombination enhancers. As transposon mobility in plant genomes is restricted by DNA methylation, we used the met1 DNA methyltransferase mutant to investigate the role of heterochromatin in SPO11-1-oligo distributions. Epigenetic activation of meiotic DSBs in proximity to centromeres and transposons occurred in met1 mutants, coincident with reduced nucleosome occupancy, gain of transcription, and H3K4me3. Together, our work reveals a complex relationship between chromatin and meiotic DSBs within A. thaliana genes and transposons, with significance for the diversity and evolution of plant genomes.
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Affiliation(s)
- Kyuha Choi
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Xiaohui Zhao
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Andrew J Tock
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Christophe Lambing
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Charles J Underwood
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
- Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Thomas J Hardcastle
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Heïdi Serra
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Juhyun Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Hyun Seob Cho
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Jaeil Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Piotr A Ziolkowski
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Nataliya E Yelina
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
| | - Ildoo Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Robert A Martienssen
- Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Ian R Henderson
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, United Kingdom
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29
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Rowley PA, Patterson K, Sandmeyer SB, Sawyer SL. Control of yeast retrotransposons mediated through nucleoporin evolution. PLoS Genet 2018; 14:e1007325. [PMID: 29694349 PMCID: PMC5918913 DOI: 10.1371/journal.pgen.1007325] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 03/21/2018] [Indexed: 02/07/2023] Open
Abstract
Yeasts serve as hosts to several types of genetic parasites. Few studies have addressed the evolutionary trajectory of yeast genes that control the stable co-existence of these parasites with their host cell. In Saccharomyces yeasts, the retrovirus-like Ty retrotransposons must access the nucleus. We show that several genes encoding components of the yeast nuclear pore complex have experienced natural selection for substitutions that change the encoded protein sequence. By replacing these S. cerevisiae genes with orthologs from other Saccharomyces species, we discovered that natural sequence changes have affected the mobility of Ty retrotransposons. Specifically, changing the genetic sequence of NUP84 or NUP82 to match that of other Saccharomyces species alters the mobility of S. cerevisiae Ty1 and Ty3. Importantly, all tested housekeeping functions of NUP84 and NUP82 remained equivalent across species. Signatures of natural selection, resulting in altered interactions with viruses and parasitic genetic elements, are common in host defense proteins. Yet, few instances have been documented in essential housekeeping proteins. The nuclear pore complex is the gatekeeper of the nucleus. This study shows how the evolution of this large, ubiquitous eukaryotic complex can alter the replication of a molecular parasite, but concurrently maintain essential host functionalities regarding nucleocytoplasmic trafficking.
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Affiliation(s)
- Paul A. Rowley
- BioFrontiers Institute, Department of Molecular Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, United States of America
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States of America
| | - Kurt Patterson
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, United States of America
| | - Suzanne B. Sandmeyer
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, United States of America
| | - Sara L. Sawyer
- BioFrontiers Institute, Department of Molecular Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, United States of America
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30
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Poirier EZ, Goic B, Tomé-Poderti L, Frangeul L, Boussier J, Gausson V, Blanc H, Vallet T, Loyd H, Levi LI, Lanciano S, Baron C, Merkling SH, Lambrechts L, Mirouze M, Carpenter S, Vignuzzi M, Saleh MC. Dicer-2-Dependent Generation of Viral DNA from Defective Genomes of RNA Viruses Modulates Antiviral Immunity in Insects. Cell Host Microbe 2018; 23:353-365.e8. [PMID: 29503180 PMCID: PMC5857290 DOI: 10.1016/j.chom.2018.02.001] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 11/08/2017] [Accepted: 02/07/2018] [Indexed: 12/21/2022]
Abstract
The RNAi pathway confers antiviral immunity in insects. Virus-specific siRNA responses are amplified via the reverse transcription of viral RNA to viral DNA (vDNA). The nature, biogenesis, and regulation of vDNA are unclear. We find that vDNA produced during RNA virus infection of Drosophila and mosquitoes is present in both linear and circular forms. Circular vDNA (cvDNA) is sufficient to produce siRNAs that confer partially protective immunity when challenged with a cognate virus. cvDNAs bear homology to defective viral genomes (DVGs), and DVGs serve as templates for vDNA and cvDNA synthesis. Accordingly, DVGs promote the amplification of vDNA-mediated antiviral RNAi responses in infected Drosophila. Furthermore, vDNA synthesis is regulated by the DExD/H helicase domain of Dicer-2 in a mechanism distinct from its role in siRNA generation. We suggest that, analogous to mammalian RIG-I-like receptors, Dicer-2 functions like a pattern recognition receptor for DVGs to modulate antiviral immunity in insects.
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Affiliation(s)
- Enzo Z Poirier
- Institut Pasteur, Viruses and RNA Interference, Centre National de la Recherche Scientifique UMR 3569, 75015 Paris, France; Institut Pasteur, Viral Populations and Pathogenesis, Centre National de la Recherche Scientifique UMR 3569, 75015 Paris, France; University of Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, 75013 Paris, France
| | - Bertsy Goic
- Institut Pasteur, Viruses and RNA Interference, Centre National de la Recherche Scientifique UMR 3569, 75015 Paris, France
| | - Lorena Tomé-Poderti
- Institut Pasteur, Viruses and RNA Interference, Centre National de la Recherche Scientifique UMR 3569, 75015 Paris, France
| | - Lionel Frangeul
- Institut Pasteur, Viruses and RNA Interference, Centre National de la Recherche Scientifique UMR 3569, 75015 Paris, France
| | - Jérémy Boussier
- Institut Pasteur, Immunobiology of Dendritic Cells, Institut National de la Santé et de la Recherche Médicale, U1223, 75015 Paris, France
| | - Valérie Gausson
- Institut Pasteur, Viruses and RNA Interference, Centre National de la Recherche Scientifique UMR 3569, 75015 Paris, France
| | - Hervé Blanc
- Institut Pasteur, Viruses and RNA Interference, Centre National de la Recherche Scientifique UMR 3569, 75015 Paris, France; Institut Pasteur, Viral Populations and Pathogenesis, Centre National de la Recherche Scientifique UMR 3569, 75015 Paris, France
| | - Thomas Vallet
- Institut Pasteur, Viral Populations and Pathogenesis, Centre National de la Recherche Scientifique UMR 3569, 75015 Paris, France
| | - Hyelee Loyd
- Department of Animal Science, Iowa State University, Ames, IA 50010, USA
| | - Laura I Levi
- Institut Pasteur, Viral Populations and Pathogenesis, Centre National de la Recherche Scientifique UMR 3569, 75015 Paris, France
| | - Sophie Lanciano
- Institut de Recherche pour le Développement, DIADE, Université de Montpellier, Université de Perpignan, LGDP, 66860 Perpignan, France
| | - Chloé Baron
- Institut Pasteur, Viruses and RNA Interference, Centre National de la Recherche Scientifique UMR 3569, 75015 Paris, France
| | - Sarah H Merkling
- Institut Pasteur, Insect-Virus Interactions, Centre National de la Recherche Scientifique URA 3012, 75015 Paris, France
| | - Louis Lambrechts
- Institut Pasteur, Insect-Virus Interactions, Centre National de la Recherche Scientifique URA 3012, 75015 Paris, France
| | - Marie Mirouze
- Institut de Recherche pour le Développement, DIADE, Université de Montpellier, Université de Perpignan, LGDP, 66860 Perpignan, France
| | - Susan Carpenter
- Department of Animal Science, Iowa State University, Ames, IA 50010, USA
| | - Marco Vignuzzi
- Institut Pasteur, Viral Populations and Pathogenesis, Centre National de la Recherche Scientifique UMR 3569, 75015 Paris, France.
| | - Maria-Carla Saleh
- Institut Pasteur, Viruses and RNA Interference, Centre National de la Recherche Scientifique UMR 3569, 75015 Paris, France.
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31
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Ma X, Sun B, Zhu F. Molecular cloning of Kuruma shrimp Marsupenaeus japonicus endonuclease-reverse transcriptase and its positive role in white spot syndrome virus and Vibrio alginolyticus infection. FISH & SHELLFISH IMMUNOLOGY 2018; 73:297-308. [PMID: 29275132 DOI: 10.1016/j.fsi.2017.12.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 12/08/2017] [Accepted: 12/20/2017] [Indexed: 06/07/2023]
Abstract
This study investigated the function of endonuclease-reverse transcriptase (mjERT) in Marsupenaeus japonicus. The 1129 bp cDNA sequence of mjERT was cloned from M. japonicus using rapid amplification of cDNA ends (RACE) PCR, and RT-qPCR analysis indicated that mjERT was highly expressed in the gills and hepatopancreas of M. japonicus. We also found that white spot syndrome virus (WSSV) or Vibrio alginolyticus challenge could enhance the expression of mjERT. When mjERT was inhibited, immune genes such as toll, p53, hemocyanin and tumor necrosis factor-α (TNF-α) were significantly down-regulated (P < .01) in the hemocytes of shrimp, while myosin was significantly up-regulated (P < .01). We demonstrated that mjERT is very important for the progression of WSSV infection and that the cumulative mortality of WSSV-infected and V. alginolyticus-infected shrimps was significantly increased following mjERT RNA interfere (RNAi). Apoptosis data provided information to suggest that mjERT-dsRNA challenge caused less apoptosis in hemocytes in both the disease-free and viral group. We also revealed that mjERT-dsRNA treatment resulted in a lower phagocytosis rate in the hemocytes of V. alginolyticus-challenged shrimp. Finally, we found that the absence of mjERT had an significantly negative impact upon shrimp phenoloxidase (PO) activity, superoxide dismutase (SOD) activity and total hemocyte count (THC) following WSSV or V. alginolyticus infection, indicating a regulative role for mjERT in the innate immunity of shrimp in response to pathogenic infection. In summary, we concluded that mjERT might promote the anti-WSSV immune response of shrimp by regulating apoptosis, PO activity, THC and SOD activity, and also exert a positive role in the immune response against V. alginolyticus by regulating phagocytosis, SOD activity, PO activity and THC.
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Affiliation(s)
- Xiongchao Ma
- College of Animal Science and Technology, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China
| | - Baozhen Sun
- College of Animal Science and Technology, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China
| | - Fei Zhu
- College of Animal Science and Technology, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China.
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32
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Taylor MS, Altukhov I, Molloy KR, Mita P, Jiang H, Adney EM, Wudzinska A, Badri S, Ischenko D, Eng G, Burns KH, Fenyö D, Chait BT, Alexeev D, Rout MP, Boeke JD, LaCava J. Dissection of affinity captured LINE-1 macromolecular complexes. eLife 2018; 7:30094. [PMID: 29309035 PMCID: PMC5821459 DOI: 10.7554/elife.30094] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 12/18/2017] [Indexed: 12/31/2022] Open
Abstract
Long Interspersed Nuclear Element-1 (LINE-1, L1) is a mobile genetic element active in human genomes. L1-encoded ORF1 and ORF2 proteins bind L1 RNAs, forming ribonucleoproteins (RNPs). These RNPs interact with diverse host proteins, some repressive and others required for the L1 lifecycle. Using differential affinity purifications, quantitative mass spectrometry, and next generation RNA sequencing, we have characterized the proteins and nucleic acids associated with distinctive, enzymatically active L1 macromolecular complexes. Among them, we describe a cytoplasmic intermediate that we hypothesize to be the canonical ORF1p/ORF2p/L1-RNA-containing RNP, and we describe a nuclear population containing ORF2p, but lacking ORF1p, which likely contains host factors participating in target-primed reverse transcription.
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Affiliation(s)
- Martin S Taylor
- Department of Pathology, Massachusetts General Hospital, Boston, United States
| | - Ilya Altukhov
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Kelly R Molloy
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Paolo Mita
- Department of Biochemistry and Molecular Pharmacology, Institute for Systems Genetics, NYU Langone Health, New York, United States
| | - Hua Jiang
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, United States
| | - Emily M Adney
- Department of Biochemistry and Molecular Pharmacology, Institute for Systems Genetics, NYU Langone Health, New York, United States.,McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Aleksandra Wudzinska
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Sana Badri
- Department of Pathology, NYU Langone Health, New York, United States
| | - Dmitry Ischenko
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - George Eng
- Department of Pathology, Massachusetts General Hospital, Boston, United States
| | - Kathleen H Burns
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, United States.,Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - David Fenyö
- Department of Biochemistry and Molecular Pharmacology, Institute for Systems Genetics, NYU Langone Health, New York, United States
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | | | - Michael P Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, United States
| | - Jef D Boeke
- Department of Biochemistry and Molecular Pharmacology, Institute for Systems Genetics, NYU Langone Health, New York, United States
| | - John LaCava
- Department of Biochemistry and Molecular Pharmacology, Institute for Systems Genetics, NYU Langone Health, New York, United States.,Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, United States
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33
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Arkhipova IR. Using bioinformatic and phylogenetic approaches to classify transposable elements and understand their complex evolutionary histories. Mob DNA 2017; 8:19. [PMID: 29225705 PMCID: PMC5718144 DOI: 10.1186/s13100-017-0103-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 11/28/2017] [Indexed: 12/11/2022] Open
Abstract
In recent years, much attention has been paid to comparative genomic studies of transposable elements (TEs) and the ensuing problems of their identification, classification, and annotation. Different approaches and diverse automated pipelines are being used to catalogue and categorize mobile genetic elements in the ever-increasing number of prokaryotic and eukaryotic genomes, with little or no connectivity between different domains of life. Here, an overview of the current picture of TE classification and evolutionary relationships is presented, updating the diversity of TE types uncovered in sequenced genomes. A tripartite TE classification scheme is proposed to account for their replicative, integrative, and structural components, and the need to expand in vitro and in vivo studies of their structural and biological properties is emphasized. Bioinformatic studies have now become front and center of novel TE discovery, and experimental pursuits of these discoveries hold great promise for both basic and applied science.
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Affiliation(s)
- Irina R Arkhipova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA 02543 USA
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34
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Li Q, Zhang Y, Zhang Z, Li X, Yao D, Wang Y, Ouyang X, Li Y, Song W, Xiao Y. A D-genome-originated Ty1/Copia-type retrotransposon family expanded significantly in tetraploid cottons. Mol Genet Genomics 2017; 293:33-43. [PMID: 28849273 DOI: 10.1007/s00438-017-1359-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 08/08/2017] [Indexed: 10/19/2022]
Abstract
Retrotransposons comprise of a major fraction of higher plant genomes, and their proliferation and elimination have profound effects on genome evolution and gene functions as well. Previously we found a D-genome-originated Ty1/Copia-type LTR (DOCL) retrotransposon in the chromosome A08 of upland cotton. To further characterize the DOCL retrotransposon family, a total of 342 DOCL retrotransposons were identified in the sequenced cotton genomes, including 73, 157, and 112 from Gossypium raimondii, G. hirsutum, and G. barbadense, respectively. According to phylogenetic analysis, the DOCL family was divided into nine groups (G1-G9), among which five groups (G1-G4 and G9, including 292 members) were proliferated after the formation of tetraploid cottons. It was found that the majority of DOCL retrotransposons (especially those in G2, G3 and G9) inserted in non-allelic loci in G. hirsutum and G. barbadense, suggesting that their proliferations were relatively independent in different tetraploid cottons. Furthermore, DOCL retrotransposons inserted in coding regions largely eliminated expression of the targeted genes in G. hirsutum or G. barbadense. Our data suggested that recent proliferation of retrotransposon families like DOCL was one of important evolutionary forces driving diversification and evolution of tetraploid cottons.
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Affiliation(s)
- Qian Li
- Biotechnology Research Center, Chongqing Key Laboratory of Application and Safety Control of Genetically Modified Crops, Southwest University, Beibei, Chongqing, China
| | - Yue Zhang
- Biotechnology Research Center, Chongqing Key Laboratory of Application and Safety Control of Genetically Modified Crops, Southwest University, Beibei, Chongqing, China
| | - Zhengsheng Zhang
- College of Agronomy and Biological Science and Technology, Southwest University, Beibei, Chongqing, China
| | - Xianbi Li
- Biotechnology Research Center, Chongqing Key Laboratory of Application and Safety Control of Genetically Modified Crops, Southwest University, Beibei, Chongqing, China
| | - Dan Yao
- Biotechnology Research Center, Chongqing Key Laboratory of Application and Safety Control of Genetically Modified Crops, Southwest University, Beibei, Chongqing, China
| | - Yi Wang
- Biotechnology Research Center, Chongqing Key Laboratory of Application and Safety Control of Genetically Modified Crops, Southwest University, Beibei, Chongqing, China
| | - Xufen Ouyang
- Biotechnology Research Center, Chongqing Key Laboratory of Application and Safety Control of Genetically Modified Crops, Southwest University, Beibei, Chongqing, China
| | - Yaohua Li
- Biotechnology Research Center, Chongqing Key Laboratory of Application and Safety Control of Genetically Modified Crops, Southwest University, Beibei, Chongqing, China
| | - Wu Song
- Institute of Xinjiang Naturally-Colored Cotton, China Colored Cotton (Group) Company, Urumchi, Xinjiang Uygur Autonomous Region, China
| | - Yuehua Xiao
- Biotechnology Research Center, Chongqing Key Laboratory of Application and Safety Control of Genetically Modified Crops, Southwest University, Beibei, Chongqing, China.
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35
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Jangam D, Feschotte C, Betrán E. Transposable Element Domestication As an Adaptation to Evolutionary Conflicts. Trends Genet 2017; 33:817-831. [PMID: 28844698 DOI: 10.1016/j.tig.2017.07.011] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/21/2017] [Accepted: 07/25/2017] [Indexed: 12/26/2022]
Abstract
Transposable elements (TEs) are selfish genetic units that typically encode proteins that enable their proliferation in the genome and spread across individual hosts. Here we review a growing number of studies that suggest that TE proteins have often been co-opted or 'domesticated' by their host as adaptations to a variety of evolutionary conflicts. In particular, TE-derived proteins have been recurrently repurposed as part of defense systems that protect prokaryotes and eukaryotes against the proliferation of infectious or invasive agents, including viruses and TEs themselves. We argue that the domestication of TE proteins may often be the only evolutionary path toward the mitigation of the cost incurred by their own selfish activities.
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Affiliation(s)
- Diwash Jangam
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Cédric Feschotte
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT, USA; Present address: Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
| | - Esther Betrán
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA.
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36
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Novikova O, Belfort M. Mobile Group II Introns as Ancestral Eukaryotic Elements. Trends Genet 2017; 33:773-783. [PMID: 28818345 DOI: 10.1016/j.tig.2017.07.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/06/2017] [Accepted: 07/24/2017] [Indexed: 01/09/2023]
Abstract
The duality of group II introns, capable of carrying out both self-splicing and retromobility reactions, is hypothesized to have played a profound role in the evolution of eukaryotes. These introns likely provided the framework for the emergence of eukaryotic retroelements, spliceosomal introns and other key components of the spliceosome. Group II introns are found in all three domains of life and are therefore considered to be exceptionally successful mobile genetic elements. Initially identified in organellar genomes, group II introns are found in bacteria, chloroplasts, and mitochondria of plants and fungi, but not in nuclear genomes. Although there is no doubt that prokaryotic and organellar group II introns are evolutionary related, there are remarkable differences in survival strategies between them. Furthermore, an evolutionary relationship of group II introns to eukaryotic retroelements, including telomeres, and spliceosomes is unmistakable.
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Affiliation(s)
- Olga Novikova
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222, USA
| | - Marlene Belfort
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222, USA; Department of Biomedical Sciences, School of Public Health, University at Albany, 1400 Washington Avenue, Albany, NY 12222, USA.
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Belfort M. Mobile self-splicing introns and inteins as environmental sensors. Curr Opin Microbiol 2017; 38:51-58. [PMID: 28482231 DOI: 10.1016/j.mib.2017.04.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 04/12/2017] [Indexed: 12/31/2022]
Abstract
Self-splicing introns and inteins are often mobile at the level of the genome. Although these RNA and protein elements, respectively, are generally considered to be selfish parasites, group I and group II introns and inteins can be triggered by environmental cues to splice and/or to mobilize. These cues include stressors such as oxidizing agents, reactive oxygen and nitrogen species, starvation, temperature, osmolarity and DNA damage. Their sensitivity to these stimuli leads to a carefully choreographed dance between the mobile element and its host that is in tune with the cellular environment. This responsiveness to a changing milieu provides strong evidence that these diverse, self-splicing mobile elements have adapted to react to prevailing conditions, to the potential advantage of both the element and its host.
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Affiliation(s)
- Marlene Belfort
- Department of Biological Sciences and RNA Institute, University at Albany, Life Sciences Research Building 2061, 1400 Washington Avenue, Albany, NY 12222, USA.
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38
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Yang F, Xi R. Silencing transposable elements in the Drosophila germline. Cell Mol Life Sci 2017; 74:435-448. [PMID: 27600679 PMCID: PMC11107544 DOI: 10.1007/s00018-016-2353-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 08/18/2016] [Accepted: 08/30/2016] [Indexed: 10/21/2022]
Abstract
Transposable elements or transposons are DNA pieces that can move around within the genome and are, therefore, potential threat to genome stability and faithful transmission of the genetic information in the germline. Accordingly, self-defense mechanisms have evolved in the metazoan germline to silence transposons, and the primary mechanism requires the germline-specific non-coding small RNAs, named Piwi-interacting RNA (piRNAs), which are in complex with Argonaute family of PIWI proteins (the piRNA-RISC complexes), to silence transposons. piRNA-mediated transposon silencing occurs at both transcriptional and post-transcriptional levels. With the advantages of genetic manipulation and advances of sequencing technology, much progress has been made on the molecular mechanisms of piRNA-mediated transposon silencing in Drosophila melanogaster, which will be the focus of this review. Because piRNA-mediated transposon silencing is evolutionarily conserved in metazoan, model organisms, such as Drosophila, will continue to be served as pioneer systems towards the complete understanding of transposon silencing in the metazoan germline.
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Affiliation(s)
- Fu Yang
- National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
- College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Rongwen Xi
- National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China.
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Characterization of new transposable element sub-families from white clover (Trifolium repens) using PCR amplification. Genetica 2016; 144:577-589. [PMID: 27671023 DOI: 10.1007/s10709-016-9926-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 09/17/2016] [Indexed: 12/15/2022]
Abstract
Transposable elements (TEs) dominate the landscapes of most plant and animal genomes. Once considered junk DNA and genetic parasites, these interspersed, repetitive DNA elements are now known to play major roles in both genetic and epigenetic processes that sponsor genome variation and regulate gene expression. Knowledge of TE consensus sequences from elements in species whose genomes have not been sequenced is limited, and the individual TEs that are encountered in clones or short-reads rarely represent potentially canonical, let alone, functional representatives. In this study, we queried the Repbase database with eight BAC clones from white clover (Trifolium repens), identified a large number of candidate TEs, and used polymerase chain reaction and Sanger sequencing to create consensus sequences for three new TE families. The results show that TE family consensus sequences can be obtained experimentally in species for which just a single, full-length member of a TE family has been sequenced.
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Orecchini E, Doria M, Antonioni A, Galardi S, Ciafrè SA, Frassinelli L, Mancone C, Montaldo C, Tripodi M, Michienzi A. ADAR1 restricts LINE-1 retrotransposition. Nucleic Acids Res 2016; 45:155-168. [PMID: 27658966 PMCID: PMC5224506 DOI: 10.1093/nar/gkw834] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/08/2016] [Accepted: 09/09/2016] [Indexed: 12/16/2022] Open
Abstract
Adenosine deaminases acting on RNA (ADARs) are involved in RNA editing that converts adenosines to inosines in double-stranded RNAs. ADAR1 was demonstrated to be functional on different viruses exerting either antiviral or proviral effects. Concerning HIV-1, several studies showed that ADAR1 favors viral replication. The aim of this study was to investigate the composition of the ADAR1 ribonucleoprotein complex during HIV-1 expression. By using a dual-tag affinity purification procedure in cells expressing HIV-1 followed by mass spectrometry analysis, we identified 14 non-ribosomal ADAR1-interacting proteins, most of which are novel. A significant fraction of these proteins were previously demonstrated to be associated to the Long INterspersed Element 1 (LINE1 or L1) ribonucleoparticles and to regulate the life cycle of L1 retrotransposons that continuously re-enter host-genome. Hence, we investigated the function of ADAR1 in the regulation of L1 activity. By using different cell-culture based retrotransposition assays in HeLa cells, we demonstrated a novel function of ADAR1 as suppressor of L1 retrotransposition. Apparently, this inhibitory mechanism does not occur through ADAR1 editing activity. Furthermore, we showed that ADAR1 binds the basal L1 RNP complex. Overall, these data support the role of ADAR1 as regulator of L1 life cycle.
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Affiliation(s)
- Elisa Orecchini
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Via Montpellier 1, Rome 00133, Italy
| | - Margherita Doria
- Laboratory of Immunoinfectivology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, Rome 00165, Italy
| | - Ambra Antonioni
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Via Montpellier 1, Rome 00133, Italy
| | - Silvia Galardi
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Via Montpellier 1, Rome 00133, Italy
| | - Silvia Anna Ciafrè
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Via Montpellier 1, Rome 00133, Italy
| | - Loredana Frassinelli
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Via Montpellier 1, Rome 00133, Italy
| | - Carmine Mancone
- Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Cellular Biotechnologies and Haematology, Sapienza University of Rome, Italy.,L. Spallanzani National Institute for Infectious Diseases, IRCCS, via Portuense 292, Rome 00149, Italy
| | - Claudia Montaldo
- L. Spallanzani National Institute for Infectious Diseases, IRCCS, via Portuense 292, Rome 00149, Italy
| | - Marco Tripodi
- Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Cellular Biotechnologies and Haematology, Sapienza University of Rome, Italy.,L. Spallanzani National Institute for Infectious Diseases, IRCCS, via Portuense 292, Rome 00149, Italy
| | - Alessandro Michienzi
- Department of Biomedicine and Prevention, University of Rome 'Tor Vergata', Via Montpellier 1, Rome 00133, Italy
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Magnan C, Yu J, Chang I, Jahn E, Kanomata Y, Wu J, Zeller M, Oakes M, Baldi P, Sandmeyer S. Sequence Assembly of Yarrowia lipolytica Strain W29/CLIB89 Shows Transposable Element Diversity. PLoS One 2016; 11:e0162363. [PMID: 27603307 PMCID: PMC5014426 DOI: 10.1371/journal.pone.0162363] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 08/22/2016] [Indexed: 12/27/2022] Open
Abstract
Yarrowia lipolytica, an oleaginous yeast, is capable of accumulating significant cellular mass in lipid making it an important source of biosustainable hydrocarbon-based chemicals. In spite of a similar number of protein-coding genes to that in other Hemiascomycetes, the Y. lipolytica genome is almost double that of model yeasts. Despite its economic importance and several distinct strains in common use, an independent genome assembly exists for only one strain. We report here a de novo annotated assembly of the chromosomal genome of an industrially-relevant strain, W29/CLIB89, determined by hybrid next-generation sequencing. For the first time, each Y. lipolytica chromosome is represented by a single contig. The telomeric rDNA repeats were localized by Irys long-range genome mapping and one complete copy of the rDNA sequence is reported. Two large structural variants and retroelement differences with reference strain CLIB122 including a full-length, novel Ty3/Gypsy long terminal repeat (LTR) retrotransposon and multiple LTR-like sequences are described. Strikingly, several of these are adjacent to RNA polymerase III-transcribed genes, which are almost double in number in Y. lipolytica compared to other Hemiascomycetes. In addition to previously-reported dimeric RNA polymerase III-transcribed genes, tRNA pseudogenes were identified. Multiple full-length and truncated LINE elements are also present. Therefore, although identified transposons do not constitute a significant fraction of the Y. lipolytica genome, they could have played an active role in its evolution. Differences between the sequence of this strain and of the existing reference strain underscore the utility of an additional independent genome assembly for this economically important organism.
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Affiliation(s)
- Christophe Magnan
- Department of Computer Science, School of Computer Sciences, University of California Irvine, Irvine, California, United States of America
- Institute for Genomics and Bioinformatics, University of California Irvine, Irvine, California, United States of America
| | - James Yu
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California, United States of America
| | - Ivan Chang
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California, United States of America
| | - Ethan Jahn
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California, United States of America
| | - Yuzo Kanomata
- Department of Computer Science, School of Computer Sciences, University of California Irvine, Irvine, California, United States of America
- Institute for Genomics and Bioinformatics, University of California Irvine, Irvine, California, United States of America
| | - Jenny Wu
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California, United States of America
| | - Michael Zeller
- Department of Computer Science, School of Computer Sciences, University of California Irvine, Irvine, California, United States of America
| | - Melanie Oakes
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California, United States of America
| | - Pierre Baldi
- Department of Computer Science, School of Computer Sciences, University of California Irvine, Irvine, California, United States of America
- Institute for Genomics and Bioinformatics, University of California Irvine, Irvine, California, United States of America
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California, United States of America
| | - Suzanne Sandmeyer
- Institute for Genomics and Bioinformatics, University of California Irvine, Irvine, California, United States of America
- Department of Biological Chemistry, School of Medicine, University of California Irvine, Irvine, California, United States of America
- * E-mail:
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42
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Nisa-Martínez R, Molina-Sánchez MD, Toro N. Host Factors Influencing the Retrohoming Pathway of Group II Intron RmInt1, Which Has an Intron-Encoded Protein Naturally Devoid of Endonuclease Activity. PLoS One 2016; 11:e0162275. [PMID: 27588750 PMCID: PMC5010178 DOI: 10.1371/journal.pone.0162275] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 08/21/2016] [Indexed: 11/21/2022] Open
Abstract
Bacterial group II introns are self-splicing catalytic RNAs and mobile retroelements that have an open reading frame encoding an intron-encoded protein (IEP) with reverse transcriptase (RT) and RNA splicing or maturase activity. Some IEPs carry a DNA endonuclease (En) domain, which is required to cleave the bottom strand downstream from the intron-insertion site for target DNA-primed reverse transcription (TPRT) of the inserted intron RNA. Host factors complete the insertion of the intron. By contrast, the major retrohoming pathway of introns with IEPs naturally lacking endonuclease activity, like the Sinorhizobium meliloti intron RmInt1, is thought to involve insertion of the intron RNA into the template for lagging strand DNA synthesis ahead of the replication fork, with possible use of the nascent strand to prime reverse transcription of the intron RNA. The host factors influencing the retrohoming pathway of such introns have not yet been described. Here, we identify key candidates likely to be involved in early and late steps of RmInt1 retrohoming. Some of these host factors are common to En+ group II intron retrohoming, but some have different functions. Our results also suggest that the retrohoming process of RmInt1 may be less dependent on the intracellular free Mg2+ concentration than those of other group II introns.
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Affiliation(s)
- Rafael Nisa-Martínez
- Structure, Dynamics and Function of Rhizobacterial Genomes, Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Calle Profesor Albareda 1, 18008, Granada, Spain
| | - María Dolores Molina-Sánchez
- Structure, Dynamics and Function of Rhizobacterial Genomes, Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Calle Profesor Albareda 1, 18008, Granada, Spain
| | - Nicolás Toro
- Structure, Dynamics and Function of Rhizobacterial Genomes, Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Calle Profesor Albareda 1, 18008, Granada, Spain
- * E-mail:
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Abstract
Retrotransposons have generated about 40 % of the human genome. This review examines the strategies the cell has evolved to coexist with these genomic "parasites", focussing on the non-long terminal repeat retrotransposons of humans and mice. Some of the restriction factors for retrotransposition, including the APOBECs, MOV10, RNASEL, SAMHD1, TREX1, and ZAP, also limit replication of retroviruses, including HIV, and are part of the intrinsic immune system of the cell. Many of these proteins act in the cytoplasm to degrade retroelement RNA or inhibit its translation. Some factors act in the nucleus and involve DNA repair enzymes or epigenetic processes of DNA methylation and histone modification. RISC and piRNA pathway proteins protect the germline. Retrotransposon control is relaxed in some cell types, such as neurons in the brain, stem cells, and in certain types of disease and cancer, with implications for human health and disease. This review also considers potential pitfalls in interpreting retrotransposon-related data, as well as issues to consider for future research.
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Affiliation(s)
- John L. Goodier
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD USA 212051
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44
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Restriction of Retrotransposon Mobilization in Schizosaccharomyces pombe by Transcriptional Silencing and Higher-Order Chromatin Organization. Genetics 2016; 203:1669-78. [PMID: 27343236 PMCID: PMC4981269 DOI: 10.1534/genetics.116.189118] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/20/2016] [Indexed: 12/23/2022] Open
Abstract
Uncontrolled propagation of retrotransposons is potentially detrimental to host genome integrity. Therefore, cells have evolved surveillance mechanisms to restrict the mobility of these elements. In Schizosaccharomyces pombe the Tf2 LTR retrotransposons are transcriptionally silenced and are also clustered in the nucleus into structures termed Tf bodies. Here we describe the impact of silencing and clustering on the mobility of an endogenous Tf2 element. Deletion of genes such as set1+ (histone H3 lysine 4 methyltransferase) or abp1+ (CENP-B homolog) that both alleviate silencing and clustering, result in a corresponding increase in mobilization. Furthermore, expression of constitutively active Sre1, a transcriptional activator of Tf2 elements, also alleviates clustering and induces mobilization. In contrast, clustering is not disrupted by loss of the HIRA histone chaperone, despite high levels of expression, and in this background, mobilization frequency is only marginally increased. Thus, mutations that compromise transcriptional silencing but not Tf bodies are insufficient to drive mobilization. Furthermore, analyses of mutant alleles that separate the transcriptional repression and clustering functions of Set1 are consistent with control of Tf2 propagation via a combination of silencing and spatial organization. Our results indicate that host surveillance mechanisms operate at multiple levels to restrict Tf2 retrotransposon mobilization.
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Abstract
This review focuses on recent developments in our understanding of group II intron function, the relationships of these introns to retrotransposons and spliceosomes, and how their common features have informed thinking about bacterial group II introns as key elements in eukaryotic evolution. Reverse transcriptase-mediated and host factor-aided intron retrohoming pathways are considered along with retrotransposition mechanisms to novel sites in bacteria, where group II introns are thought to have originated. DNA target recognition and movement by target-primed reverse transcription infer an evolutionary relationship among group II introns, non-LTR retrotransposons, such as LINE elements, and telomerase. Additionally, group II introns are almost certainly the progenitors of spliceosomal introns. Their profound similarities include splicing chemistry extending to RNA catalysis, reaction stereochemistry, and the position of two divalent metals that perform catalysis at the RNA active site. There are also sequence and structural similarities between group II introns and the spliceosome's small nuclear RNAs (snRNAs) and between a highly conserved core spliceosomal protein Prp8 and a group II intron-like reverse transcriptase. It has been proposed that group II introns entered eukaryotes during bacterial endosymbiosis or bacterial-archaeal fusion, proliferated within the nuclear genome, necessitating evolution of the nuclear envelope, and fragmented giving rise to spliceosomal introns. Thus, these bacterial self-splicing mobile elements have fundamentally impacted the composition of extant eukaryotic genomes, including the human genome, most of which is derived from close relatives of mobile group II introns.
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46
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Sontheimer EJ, Marraffini LA. CRISPR goes retro. Science 2016; 351:920-1. [DOI: 10.1126/science.aaf2851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
RNA contributes directly to the immunological memory recorded in CRISPR sequences
[Also see Research Article by
Silas
et al.
]
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Affiliation(s)
- Erik J. Sontheimer
- RNA Therapeutics Institute, Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
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47
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Cheung S, Ma L, Chan PHW, Hu HL, Mayor T, Chen HT, Measday V. Ty1 Integrase Interacts with RNA Polymerase III-specific Subcomplexes to Promote Insertion of Ty1 Elements Upstream of Polymerase (Pol) III-transcribed Genes. J Biol Chem 2016; 291:6396-411. [PMID: 26797132 DOI: 10.1074/jbc.m115.686840] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Indexed: 01/01/2023] Open
Abstract
Retrotransposons are eukaryotic mobile genetic elements that transpose by reverse transcription of an RNA intermediate and are derived from retroviruses. The Ty1 retrotransposon of Saccharomyces cerevisiae belongs to the Ty1/Copia superfamily, which is present in every eukaryotic genome. Insertion of Ty1 elements into the S. cerevisiae genome, which occurs upstream of genes transcribed by RNA Pol III, requires the Ty1 element-encoded integrase (IN) protein. Here, we report that Ty1-IN interacts in vivo and in vitro with RNA Pol III-specific subunits to mediate insertion of Ty1 elements upstream of Pol III-transcribed genes. Purification of Ty1-IN from yeast cells followed by mass spectrometry (MS) analysis identified an enrichment of peptides corresponding to the Rpc82/34/31 and Rpc53/37 Pol III-specific subcomplexes. GFP-Trap purification of multiple GFP-tagged RNA Pol III subunits from yeast extracts revealed that the majority of Pol III subunits co-purify with Ty1-IN but not two other complexes required for Pol III transcription, transcription initiation factors (TF) IIIB and IIIC. In vitro binding studies with bacterially purified RNA Pol III proteins demonstrate that Rpc31, Rpc34, and Rpc53 interact directly with Ty1-IN. Deletion of the N-terminal 280 amino acids of Rpc53 abrogates insertion of Ty1 elements upstream of the hot spot SUF16 tRNA locus and abolishes the interaction of Ty1-IN with Rpc37. The Rpc53/37 complex therefore has an important role in targeting Ty1-IN to insert Ty1 elements upstream of Pol III-transcribed genes.
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Affiliation(s)
- Stephanie Cheung
- From the Department of Biochemistry and Molecular Biology, Wine Research Centre, and
| | | | - Patrick H W Chan
- Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada and
| | - Hui-Lan Hu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 115
| | - Thibault Mayor
- From the Department of Biochemistry and Molecular Biology, Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada and
| | - Hung-Ta Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 115
| | - Vivien Measday
- From the Department of Biochemistry and Molecular Biology, Wine Research Centre, and
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Rose NH, Seneca FO, Palumbi SR. Gene Networks in the Wild: Identifying Transcriptional Modules that Mediate Coral Resistance to Experimental Heat Stress. Genome Biol Evol 2015; 8:243-52. [PMID: 26710855 PMCID: PMC4758253 DOI: 10.1093/gbe/evv258] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Organisms respond to environmental variation partly through changes in gene expression, which underlie both homeostatic and acclimatory responses to environmental stress. In some cases, so many genes change in expression in response to different influences that understanding expression patterns for all these individual genes becomes difficult. To reduce this problem, we use a systems genetics approach to show that variation in the expression of thousands of genes of reef-building corals can be explained as variation in the expression of a small number of coexpressed “modules.” Modules were often enriched for specific cellular functions and varied predictably among individuals, experimental treatments, and physiological state. We describe two transcriptional modules for which expression levels immediately after heat stress predict bleaching a day later. One of these early “bleaching modules” is enriched for sequence-specific DNA-binding proteins, particularly E26 transformation-specific (ETS)-family transcription factors. The other module is enriched for extracellular matrix proteins. These classes of bleaching response genes are clear in the modular gene expression analysis we conduct but are much more difficult to discern in single gene analyses. Furthermore, the ETS-family module shows repeated differences in expression among coral colonies grown in the same common garden environment, suggesting a heritable genetic or epigenetic basis for these expression polymorphisms. This finding suggests that these corals harbor high levels of gene-network variation, which could facilitate rapid evolution in the face of environmental change.
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Affiliation(s)
- Noah H Rose
- Biology Department, Stanford University, Hopkins Marine Station
| | - Francois O Seneca
- Biology Department, Stanford University, Hopkins Marine Station Present address: Kewalo Marine Lab, University of Hawaii, Honolulu, HI
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49
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Wylie A, Jones AE, D'Brot A, Lu WJ, Kurtz P, Moran JV, Rakheja D, Chen KS, Hammer RE, Comerford SA, Amatruda JF, Abrams JM. p53 genes function to restrain mobile elements. Genes Dev 2015; 30:64-77. [PMID: 26701264 PMCID: PMC4701979 DOI: 10.1101/gad.266098.115] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 11/23/2015] [Indexed: 11/24/2022]
Abstract
Wylie et al. show that p53 restricts retrotransposon activity and genetically interacts with components of the piRNA pathway. In gene complementation studies, normal human p53 alleles restrained these mobile elements, but mutant p53 alleles from cancer patients could not. Consistent with these observations, they also found patterns of unrestrained retrotransposons in p53-driven mouse and human cancers. Throughout the animal kingdom, p53 genes govern stress response networks by specifying adaptive transcriptional responses. The human member of this gene family is mutated in most cancers, but precisely how p53 functions to mediate tumor suppression is not well understood. Using Drosophila and zebrafish models, we show that p53 restricts retrotransposon activity and genetically interacts with components of the piRNA (piwi-interacting RNA) pathway. Furthermore, transposon eruptions occurring in the p53− germline were incited by meiotic recombination, and transcripts produced from these mobile elements accumulated in the germ plasm. In gene complementation studies, normal human p53 alleles suppressed transposons, but mutant p53 alleles from cancer patients could not. Consistent with these observations, we also found patterns of unrestrained retrotransposons in p53-driven mouse and human cancers. Furthermore, p53 status correlated with repressive chromatin marks in the 5′ sequence of a synthetic LINE-1 element. Together, these observations indicate that ancestral functions of p53 operate through conserved mechanisms to contain retrotransposons. Since human p53 mutants are disabled for this activity, our findings raise the possibility that p53 mitigates oncogenic disease in part by restricting transposon mobility.
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Affiliation(s)
- Annika Wylie
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Amanda E Jones
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Alejandro D'Brot
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Wan-Jin Lu
- Stanford University Medical Center, Stanford, California 94305, USA
| | - Paula Kurtz
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - John V Moran
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan 48019, USA; Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48019, USA; Howard Hughes Medical Institute, University of Michigan Medical School, Ann Arbor, Michigan 48019, USA
| | - Dinesh Rakheja
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Kenneth S Chen
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Robert E Hammer
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Sarah A Comerford
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - James F Amatruda
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - John M Abrams
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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Preferential retrotransposition in aging yeast mother cells is correlated with increased genome instability. DNA Repair (Amst) 2015; 34:18-27. [PMID: 26298836 DOI: 10.1016/j.dnarep.2015.07.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 07/05/2015] [Accepted: 07/19/2015] [Indexed: 01/02/2023]
Abstract
Retrotransposon expression or mobility is increased with age in multiple species and could promote genome instability or altered gene expression during aging. However, it is unclear whether activation of retrotransposons during aging is an indirect result of global changes in chromatin and gene regulation or a result of retrotransposon-specific mechanisms. Retromobility of a marked chromosomal Ty1 retrotransposon in Saccharomyces cerevisiae was elevated in mother cells relative to their daughter cells, as determined by magnetic cell sorting of mothers and daughters. Retromobility frequencies in aging mother cells were significantly higher than those predicted by cell age and the rate of mobility in young populations, beginning when mother cells were only several generations old. New Ty1 insertions in aging mothers were more strongly correlated with gross chromosome rearrangements than in young cells and were more often at non-preferred target sites. Mother cells were more likely to have high concentrations and bright foci of Ty1 Gag-GFP than their daughter cells. Levels of extrachromosomal Ty1 cDNA were also significantly higher in aged mother cell populations than their daughter cell populations. These observations are consistent with a retrotransposon-specific mechanism that causes retrotransposition to occur preferentially in yeast mother cells as they begin to age, as opposed to activation by phenotypic changes associated with very old age. These findings will likely be relevant for understanding retrotransposons and aging in many organisms, based on similarities in regulation and consequences of retrotransposition in diverse species.
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