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Hannon-Hatfield JA, Chen J, Bergman CM, Garfinkel DJ. Evolution of a Restriction Factor by Domestication of a Yeast Retrotransposon. Mol Biol Evol 2024; 41:msae050. [PMID: 38442736 PMCID: PMC10951436 DOI: 10.1093/molbev/msae050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 02/13/2024] [Accepted: 02/23/2024] [Indexed: 03/07/2024] Open
Abstract
Transposable elements drive genome evolution in all branches of life. Transposable element insertions are often deleterious to their hosts and necessitate evolution of control mechanisms to limit their spread. The long terminal repeat retrotransposon Ty1 prime (Ty1'), a subfamily of the Ty1 family, is present in many Saccharomyces cerevisiae strains, but little is known about what controls its copy number. Here, we provide evidence that a novel gene from an exapted Ty1' sequence, domesticated restriction of Ty1' relic 2 (DRT2), encodes a restriction factor that inhibits Ty1' movement. DRT2 arose through domestication of a Ty1' GAG gene and contains the C-terminal domain of capsid, which in the related Ty1 canonical subfamily functions as a self-encoded restriction factor. Bioinformatic analysis reveals the widespread nature of DRT2, its evolutionary history, and pronounced structural variation at the Ty1' relic 2 locus. Ty1' retromobility analyses demonstrate DRT2 restriction factor functionality, and northern blot and RNA-seq analysis indicate that DRT2 is transcribed in multiple strains. Velocity cosedimentation profiles indicate an association between Drt2 and Ty1' virus-like particles or assembly complexes. Chimeric Ty1' elements containing DRT2 retain retromobility, suggesting an ancestral role of productive Gag C-terminal domain of capsid functionality is present in the sequence. Unlike Ty1 canonical, Ty1' retromobility increases with copy number, suggesting that C-terminal domain of capsid-based restriction is not limited to the Ty1 canonical subfamily self-encoded restriction factor and drove the endogenization of DRT2. The discovery of an exapted Ty1' restriction factor provides insight into the evolution of the Ty1 family, evolutionary hot-spots, and host-transposable element interactions.
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Affiliation(s)
- J Adam Hannon-Hatfield
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - Jingxuan Chen
- Institute of Bioinformatics, University of Georgia, Athens, GA, USA
| | - Casey M Bergman
- Institute of Bioinformatics, University of Georgia, Athens, GA, USA
- Department of Genetics, University of Georgia, Athens, GA, USA
| | - David J Garfinkel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
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2
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Gusa A, Yadav V, Roth C, Williams JD, Shouse EM, Magwene P, Heitman J, Jinks-Robertson S. Genome-wide analysis of heat stress-stimulated transposon mobility in the human fungal pathogen Cryptococcus deneoformans. Proc Natl Acad Sci U S A 2023; 120:e2209831120. [PMID: 36669112 DOI: 10.1073/pnas.2209831120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
We recently reported transposon mutagenesis as a significant driver of spontaneous mutations in the human fungal pathogen Cryptococcus deneoformans during murine infection. Mutations caused by transposable element (TE) insertion into reporter genes were dramatically elevated at high temperatures (37° vs. 30°) in vitro, suggesting that heat stress stimulates TE mobility in the Cryptococcus genome. To explore the genome-wide impact of TE mobilization, we generated transposon accumulation lines by in vitro passage of C. deneoformans strain XL280α for multiple generations at both 30° and at the host-relevant temperature of 37°. Utilizing whole-genome sequencing, we identified native TE copies and mapped multiple de novo TE insertions in these lines. Movements of the T1 DNA transposon occurred at both temperatures with a strong bias for insertion between gene-coding regions. By contrast, the Tcn12 retrotransposon integrated primarily within genes and movement occurred exclusively at 37°. In addition, we observed a dramatic amplification in copy number of the Cnl1 (Cryptococcus neoformans LINE-1) retrotransposon in subtelomeric regions under heat-stress conditions. Comparing TE mutations to other sequence variations detected in passaged lines, the increase in genomic changes at elevated temperatures was primarily due to mobilization of the retroelements Tcn12 and Cnl1. Finally, we found multiple TE movements (T1, Tcn12, and Cnl1) in the genomes of single C. deneoformans isolates recovered from infected mice, providing evidence that mobile elements are likely to facilitate microevolution and rapid adaptation during infection.
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3
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Chen J, McQueary H, Hall DW, Philippsen P, Garfinkel DJ, Bergman CM. Genome Assembly of the Ty1-Less Saccharomyces paradoxus Strain DG1768. Microbiol Resour Announc 2022; 11:e0086821. [PMID: 35049349 DOI: 10.1128/mra.00868-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Here, we report an essentially complete genome assembly for the Ty1-less Saccharomyces paradoxus strain DG1768 (derivative of strain 337) based on PacBio and Illumina shotgun sequence data. We also document the genetic alterations that make this yeast strain a key resource for Ty1 mobility studies.
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4
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Drouin M, Hénault M, Hallin J, Landry CR. Testing the Genomic Shock Hypothesis Using Transposable Element Expression in Yeast Hybrids. Front Fungal Biol 2021; 2:729264. [PMID: 37744137 PMCID: PMC10512236 DOI: 10.3389/ffunb.2021.729264] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 07/26/2021] [Indexed: 09/26/2023]
Abstract
Transposable element (TE) insertions are a source of structural variation and can cause genetic instability and gene expression changes. A host can limit the spread of TEs with various repression mechanisms. Many examples of plant and animal interspecific hybrids show disrupted TE repression leading to TE propagation. Recent studies in yeast did not find any increase in transposition rate in hybrids. However, this does not rule out the possibility that the transcriptional or translational activity of TEs increases following hybridization because of a disruption of the host TE control mechanisms. Thus, whether total expression of a TE family is higher in hybrids than in their parental species remains to be examined. We leveraged publically available RNA-seq and ribosomal profiling data on yeast artificial hybrids of the Saccharomyces genus and performed differential expression analysis of their LTR retrotransposons (Ty elements). Our analyses of total mRNA levels show that Ty elements are generally not differentially expressed in hybrids, even when the hybrids are exposed to a low temperature stress condition. Overall, only 2/26 Ty families show significantly higher expression in the S. cerevisiae × S. uvarum hybrids while there are 3/26 showing significantly lower expression in the S. cerevisiae x S. paradoxus hybrids. Our analysis of ribosome profiling data of S. cerevisiae × S. paradoxus hybrids shows similar translation efficiency of Ty in both parents and hybrids, except for Ty1_cer showing higher translation efficiency. Overall, our results do not support the hypothesis that hybridization could act as a systematic trigger of TE expression in yeast and suggest that the impact of hybridization on TE activity is strain and TE specific.
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Affiliation(s)
- Marika Drouin
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Université Laval, Québec, QC, Canada
- PROTEO - Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
| | - Mathieu Hénault
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Université Laval, Québec, QC, Canada
- PROTEO - Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
| | - Johan Hallin
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Université Laval, Québec, QC, Canada
- PROTEO - Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
- Département de Biologie, Université Laval, Québec, QC, Canada
| | - Christian R. Landry
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Université Laval, Québec, QC, Canada
- PROTEO - Regroupement Québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines, Québec, QC, Canada
- Centre de Recherche en Données Massives de l'Université Laval, Université Laval, Québec, QC, Canada
- Département de Biologie, Université Laval, Québec, QC, Canada
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5
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Bleykasten-Grosshans C, Fabrizio R, Friedrich A, Schacherer J. Species-wide transposable element repertoires retrace the evolutionary history of the Saccharomyces cerevisiae host. Mol Biol Evol 2021; 38:4334-4345. [PMID: 34115140 PMCID: PMC8476168 DOI: 10.1093/molbev/msab171] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Transposable elements (TE) are an important source of genetic variation with a dynamic and content that greatly differ in a wide range of species. The origin of the intraspecific content variation is not always clear and little is known about the precise nature of it. Here, we surveyed the species-wide content of the Ty LTR-retrotransposons in a broad collection of 1,011 Saccharomyces cerevisiae natural isolates to understand what can stand behind the variation of the repertoire that is the type and number of Ty elements. We have compiled an exhaustive catalog of all the TE sequence variants present in the S. cerevisiae species by identifying a large set of new sequence variants. The characterization of the TE content in each isolate clearly highlighted that each subpopulation exhibits a unique and specific repertoire, retracing the evolutionary history of the species. Most interestingly, we have shown that ancient interspecific hybridization events had a major impact in the birth of new sequence variants and therefore in the shaping of the TE repertoires. We also investigated the transpositional activity of these elements in a large set of natural isolates, and we found a broad variability related to the level of ploidy as well as the genetic background. Overall, our results pointed out that the evolution of the Ty content is deeply impacted by clade-specific events such as introgressions and therefore follows the population structure. In addition, our study lays the foundation for future investigations to better understand the transpositional regulation and more broadly the TE–host interactions.
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Affiliation(s)
| | - Romeo Fabrizio
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
| | - Anne Friedrich
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France
| | - Joseph Schacherer
- Université de Strasbourg, CNRS, GMGM UMR 7156, Strasbourg, France.,Institut Universitaire de France (IUF)
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6
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Smukowski Heil C, Patterson K, Hickey ASM, Alcantara E, Dunham MJ. Transposable Element Mobilization in Interspecific Yeast Hybrids. Genome Biol Evol 2021; 13:6141023. [PMID: 33595639 PMCID: PMC7952228 DOI: 10.1093/gbe/evab033] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2021] [Indexed: 12/13/2022] Open
Abstract
Barbara McClintock first hypothesized that interspecific hybridization could provide a “genomic shock” that leads to the mobilization of transposable elements (TEs). This hypothesis is based on the idea that regulation of TE movement is potentially disrupted in hybrids. However, the handful of studies testing this hypothesis have yielded mixed results. Here, we set out to identify if hybridization can increase transposition rate and facilitate colonization of TEs in Saccharomyces cerevisiae × Saccharomyces uvarum interspecific yeast hybrids. Saccharomyces cerevisiae have a small number of active long terminal repeat retrotransposons (Ty elements), whereas their distant relative S. uvarum have lost the Ty elements active in S. cerevisiae. Although the regulation system of Ty elements is known in S. cerevisiae, it is unclear how Ty elements are regulated in other Saccharomyces species, and what mechanisms contributed to the loss of most classes of Ty elements in S. uvarum. Therefore, we first assessed whether TEs could insert in the S. uvarum sub-genome of a S. cerevisiae × S. uvarum hybrid. We induced transposition to occur in these hybrids and developed a sequencing technique to show that Ty elements insert readily and nonrandomly in the S. uvarum genome. We then used an in vivo reporter construct to directly measure transposition rate in hybrids, demonstrating that hybridization itself does not alter rate of mobilization. However, we surprisingly show that species-specific mitochondrial inheritance can change transposition rate by an order of magnitude. Overall, our results provide evidence that hybridization can potentially facilitate the introduction of TEs across species boundaries and alter transposition via mitochondrial transmission, but that this does not lead to unrestrained proliferation of TEs suggested by the genomic shock theory.
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Affiliation(s)
- Caiti Smukowski Heil
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Kira Patterson
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | | | - Erica Alcantara
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Maitreya J Dunham
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
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7
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Meers C, Keskin H, Banyai G, Mazina O, Yang T, Gombolay AL, Mukherjee K, Kaparos EI, Newnam G, Mazin A, Storici F. Genetic Characterization of Three Distinct Mechanisms Supporting RNA-Driven DNA Repair and Modification Reveals Major Role of DNA Polymerase ζ. Mol Cell 2020; 79:1037-1050.e5. [PMID: 32882183 DOI: 10.1016/j.molcel.2020.08.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 06/30/2020] [Accepted: 08/12/2020] [Indexed: 01/08/2023]
Abstract
DNA double-stranded breaks (DSBs) are dangerous lesions threatening genomic stability. Fidelity of DSB repair is best achieved by recombination with a homologous template sequence. In yeast, transcript RNA was shown to template DSB repair of DNA. However, molecular pathways of RNA-driven repair processes remain obscure. Utilizing assays of RNA-DNA recombination with and without an induced DSB in yeast DNA, we characterize three forms of RNA-mediated genomic modifications: RNA- and cDNA-templated DSB repair (R-TDR and c-TDR) using an RNA transcript or a DNA copy of the RNA transcript for DSB repair, respectively, and a new mechanism of RNA-templated DNA modification (R-TDM) induced by spontaneous or mutagen-induced breaks. While c-TDR requires reverse transcriptase, translesion DNA polymerase ζ (Pol ζ) plays a major role in R-TDR, and it is essential for R-TDM. This study characterizes mechanisms of RNA-DNA recombination, uncovering a role of Pol ζ in transferring genetic information from transcript RNA to DNA.
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Affiliation(s)
- Chance Meers
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Havva Keskin
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Gabor Banyai
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Olga Mazina
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Taehwan Yang
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Alli L Gombolay
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Kuntal Mukherjee
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Efiyenia I Kaparos
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Gary Newnam
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Alexander Mazin
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Francesca Storici
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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8
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Asif‐Laidin A, Conesa C, Bonnet A, Grison C, Adhya I, Menouni R, Fayol H, Palmic N, Acker J, Lesage P. A small targeting domain in Ty1 integrase is sufficient to direct retrotransposon integration upstream of tRNA genes. EMBO J 2020; 39:e104337. [PMID: 32677087 PMCID: PMC7459421 DOI: 10.15252/embj.2019104337] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 06/09/2020] [Accepted: 06/18/2020] [Indexed: 12/25/2022] Open
Abstract
Integration of transposable elements into the genome is mutagenic. Mechanisms targeting integrations into relatively safe locations, hence minimizing deleterious consequences for cell fitness, have emerged during evolution. In budding yeast, integration of the Ty1 LTR retrotransposon upstream of RNA polymerase III (Pol III)-transcribed genes requires interaction between Ty1 integrase (IN1) and AC40, a subunit common to Pol I and Pol III. Here, we identify the Ty1 targeting domain of IN1 that ensures (i) IN1 binding to Pol I and Pol III through AC40, (ii) IN1 genome-wide recruitment to Pol I- and Pol III-transcribed genes, and (iii) Ty1 integration only at Pol III-transcribed genes, while IN1 recruitment by AC40 is insufficient to target Ty1 integration into Pol I-transcribed genes. Swapping the targeting domains between Ty5 and Ty1 integrases causes Ty5 integration at Pol III-transcribed genes, indicating that the targeting domain of IN1 alone confers Ty1 integration site specificity.
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Affiliation(s)
- Amna Asif‐Laidin
- INSERM U944, CNRS UMR 7212Genomes& Cell Biology of Disease UnitInstitut de Recherche Saint‐LouisHôpital Saint‐LouisUniversité de ParisParisFrance
| | - Christine Conesa
- CEACNRSInstitute for Integrative Biology of the Cell (I2BC)Université Paris‐SaclayGif‐sur‐YvetteFrance
| | - Amandine Bonnet
- INSERM U944, CNRS UMR 7212Genomes& Cell Biology of Disease UnitInstitut de Recherche Saint‐LouisHôpital Saint‐LouisUniversité de ParisParisFrance
| | - Camille Grison
- INSERM U944, CNRS UMR 7212Genomes& Cell Biology of Disease UnitInstitut de Recherche Saint‐LouisHôpital Saint‐LouisUniversité de ParisParisFrance
| | - Indranil Adhya
- CEACNRSInstitute for Integrative Biology of the Cell (I2BC)Université Paris‐SaclayGif‐sur‐YvetteFrance
| | - Rachid Menouni
- INSERM U944, CNRS UMR 7212Genomes& Cell Biology of Disease UnitInstitut de Recherche Saint‐LouisHôpital Saint‐LouisUniversité de ParisParisFrance
| | - Hélène Fayol
- INSERM U944, CNRS UMR 7212Genomes& Cell Biology of Disease UnitInstitut de Recherche Saint‐LouisHôpital Saint‐LouisUniversité de ParisParisFrance
| | - Noé Palmic
- INSERM U944, CNRS UMR 7212Genomes& Cell Biology of Disease UnitInstitut de Recherche Saint‐LouisHôpital Saint‐LouisUniversité de ParisParisFrance
| | - Joël Acker
- CEACNRSInstitute for Integrative Biology of the Cell (I2BC)Université Paris‐SaclayGif‐sur‐YvetteFrance
| | - Pascale Lesage
- INSERM U944, CNRS UMR 7212Genomes& Cell Biology of Disease UnitInstitut de Recherche Saint‐LouisHôpital Saint‐LouisUniversité de ParisParisFrance
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9
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Gusa A, Williams JD, Cho JE, Averette AF, Sun S, Shouse EM, Heitman J, Alspaugh JA, Jinks-Robertson S. Transposon mobilization in the human fungal pathogen Cryptococcus is mutagenic during infection and promotes drug resistance in vitro. Proc Natl Acad Sci U S A 2020; 117:9973-80. [PMID: 32303657 DOI: 10.1073/pnas.2001451117] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
When transitioning from the environment, pathogenic microorganisms must adapt rapidly to survive in hostile host conditions. This is especially true for environmental fungi that cause opportunistic infections in immunocompromised patients since these microbes are not well adapted human pathogens. Cryptococcus species are yeastlike fungi that cause lethal infections, especially in HIV-infected patients. Using Cryptococcus deneoformans in a murine model of infection, we examined contributors to drug resistance and demonstrated that transposon mutagenesis drives the development of 5-fluoroorotic acid (5FOA) resistance. Inactivation of target genes URA3 or URA5 primarily reflected the insertion of two transposable elements (TEs): the T1 DNA transposon and the TCN12 retrotransposon. Consistent with in vivo results, increased rates of mutagenesis and resistance to 5FOA and the antifungal drugs rapamycin/FK506 (rap/FK506) and 5-fluorocytosine (5FC) were found when Cryptococcus was incubated at 37° compared to 30° in vitro, a condition that mimics the temperature shift that occurs during the environment-to-host transition. Inactivation of the RNA interference (RNAi) pathway, which suppresses TE movement in many organisms, was not sufficient to elevate TE movement at 30° to the level observed at 37°. We propose that temperature-dependent TE mobilization in Cryptococcus is an important mechanism that enhances microbial adaptation and promotes pathogenesis and drug resistance in the human host.
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10
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Bast J, Jaron KS, Schuseil D, Roze D, Schwander T. Asexual reproduction reduces transposable element load in experimental yeast populations. eLife 2019; 8:48548. [PMID: 31486772 PMCID: PMC6783261 DOI: 10.7554/elife.48548] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 09/04/2019] [Indexed: 01/04/2023] Open
Abstract
Theory predicts that sexual reproduction can either facilitate or restrain transposable element (TE) accumulation by providing TEs with a means of spreading to all individuals in a population, versus facilitating TE load reduction via purifying selection. By quantifying genomic TE loads over time in experimental sexual and asexual Saccharomyces cerevisiae populations, we provide direct evidence that TE loads decrease rapidly under asexual reproduction. We show, using simulations, that this reduction may occur via evolution of TE activity, most likely via increased excision rates. Thus, sex is a major driver of genomic TE loads and at the root of the success of TEs. The genetic information of most living organisms contains parasitic invaders known as transposable elements. These genetic sequences multiply by copying and pasting themselves through the genome, but this process can disrupt the activity of important genes and put the organism at risk. How transposable elements proliferate in a population depends on the way organisms reproduce. If they simply clone themselves asexually, the selfish elements cannot spread between the different clones. If the organisms mate together their respective transposable elements get mixed, which helps the sequences to spread more easily and to potentially become more virulent. However, sexual reproduction also comes with mechanisms that keep transposable elements in check. Bast, Jaron et al. took advantage of the fact that yeasts can reproduce with or without mating to explore whether sexual or asexual organisms are better at controlling the spread of transposable elements. The number of copies of transposable elements in the genomes of yeast grown sexually or asexually was assessed. The results showed that sexual populations kept constant numbers of selfish elements, while asexual organisms lost these genomic parasites over time. Simulations then revealed that this difference emerged because a defense gene that helps to delete transposable elements was spreading more quickly in the asexual group. The work by Bast, Jaron et al. therefore suggests that sex is responsible for the evolutionary success of transposable elements, while asexual populations can discard these sequences over time. Sex therefore helps genetic parasites, somewhat similar to sexually transmitted diseases, to spread between individuals and remain virulent.
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Affiliation(s)
- Jens Bast
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Kamil S Jaron
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Donovan Schuseil
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Denis Roze
- UMI3614 Evolutionary Biology and Ecology of Alga, Centre National de la Recherche Scientifique (CNRS), Roscoff, France.,Station Biologique de Roscoff, Sorbonne Université, Roscoff, France
| | - Tanja Schwander
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
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11
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Møller HD, Larsen CE, Parsons L, Hansen AJ, Regenberg B, Mourier T. Formation of Extrachromosomal Circular DNA from Long Terminal Repeats of Retrotransposons in Saccharomyces cerevisiae. G3 (Bethesda) 2015; 6:453-62. [PMID: 26681518 DOI: 10.1534/g3.115.025858] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Extrachromosomal circular DNA (eccDNA) derived from chromosomal Ty retrotransposons in yeast can be generated in multiple ways. Ty eccDNA can arise from the circularization of extrachromosomal linear DNA during the transpositional life cycle of retrotransposons, or from circularization of genomic Ty DNA. Circularization may happen through nonhomologous end-joining (NHEJ) of long terminal repeats (LTRs) flanking Ty elements, by Ty autointegration, or by LTR–LTR recombination. By performing an in-depth investigation of sequence reads stemming from Ty eccDNAs obtained from populations of Saccharomyces cerevisiae S288c, we find that eccDNAs predominantly correspond to full-length Ty1 elements. Analyses of sequence junctions reveal no signs of NHEJ or autointegration events. We detect recombination junctions that are consistent with yeast Ty eccDNAs being generated through recombination events within the genome. This opens the possibility that retrotransposable elements could move around in the genome without an RNA intermediate directly through DNA circularization.
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12
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Bilanchone V, Clemens K, Kaake R, Dawson AR, Matheos D, Nagashima K, Sitlani P, Patterson K, Chang I, Huang L, Sandmeyer S. Ty3 Retrotransposon Hijacks Mating Yeast RNA Processing Bodies to Infect New Genomes. PLoS Genet 2015; 11:e1005528. [PMID: 26421679 PMCID: PMC4589538 DOI: 10.1371/journal.pgen.1005528] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 08/24/2015] [Indexed: 01/15/2023] Open
Abstract
Retrotransposition of the budding yeast long terminal repeat retrotransposon Ty3 is activated during mating. In this study, proteins that associate with Ty3 Gag3 capsid protein during virus-like particle (VLP) assembly were identified by mass spectrometry and screened for roles in mating-stimulated retrotransposition. Components of RNA processing bodies including DEAD box helicases Dhh1/DDX6 and Ded1/DDX3, Sm-like protein Lsm1, decapping protein Dcp2, and 5' to 3' exonuclease Xrn1 were among the proteins identified. These proteins associated with Ty3 proteins and RNA, and were required for formation of Ty3 VLP retrosome assembly factories and for retrotransposition. Specifically, Dhh1/DDX6 was required for normal levels of Ty3 genomic RNA, and Lsm1 and Xrn1 were required for association of Ty3 protein and RNA into retrosomes. This role for components of RNA processing bodies in promoting VLP assembly and retrotransposition during mating in a yeast that lacks RNA interference, contrasts with roles proposed for orthologous components in animal germ cell ribonucleoprotein granules in turnover and epigenetic suppression of retrotransposon RNAs.
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Affiliation(s)
- Virginia Bilanchone
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
| | - Kristina Clemens
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
| | - Robyn Kaake
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, California, United States of America
| | - Anthony R. Dawson
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
| | - Dina Matheos
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
| | - Kunio Nagashima
- Electron Microscope Laboratory, NCI-Frederick, SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Parth Sitlani
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
| | - Kurt Patterson
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
| | - Ivan Chang
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
| | - Lan Huang
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, California, United States of America
| | - Suzanne Sandmeyer
- Department of Biological Chemistry, 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
- * E-mail:
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13
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Abstract
Long-terminal repeat (LTR)-retrotransposons generate a copy of their DNA (cDNA) by reverse transcription of their RNA genome in cytoplasmic nucleocapsids. They are widespread in the eukaryotic kingdom and are the evolutionary progenitors of retroviruses [1]. The Ty1 element of the budding yeast Saccharomyces cerevisiae was the first LTR-retrotransposon demonstrated to mobilize through an RNA intermediate, and not surprisingly, is the best studied. The depth of our knowledge of Ty1 biology stems not only from the predominance of active Ty1 elements in the S. cerevisiae genome but also the ease and breadth of genomic, biochemical and cell biology approaches available to study cellular processes in yeast. This review describes the basic structure of Ty1 and its gene products, the replication cycle, the rapidly expanding compendium of host co-factors known to influence retrotransposition and the nature of Ty1's elaborate symbiosis with its host. Our goal is to illuminate the value of Ty1 as a paradigm to explore the biology of LTR-retrotransposons in multicellular organisms, where the low frequency of retrotransposition events presents a formidable barrier to investigations of retrotransposon biology.
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Saha A, Mitchell JA, Nishida Y, Hildreth JE, Ariberre JA, Gilbert WV, Garfinkel DJ. A trans-dominant form of Gag restricts Ty1 retrotransposition and mediates copy number control. J Virol 2015; 89:3922-38. [PMID: 25609815 PMCID: PMC4403431 DOI: 10.1128/jvi.03060-14] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 01/15/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Saccharomyces cerevisiae and Saccharomyces paradoxus lack the conserved RNA interference pathway and utilize a novel form of copy number control (CNC) to inhibit Ty1 retrotransposition. Although noncoding transcripts have been implicated in CNC, here we present evidence that a truncated form of the Gag capsid protein (p22) or its processed form (p18) is necessary and sufficient for CNC and likely encoded by Ty1 internal transcripts. Coexpression of p22/p18 and Ty1 decreases mobility more than 30,000-fold. p22/p18 cofractionates with Ty1 virus-like particles (VLPs) and affects VLP yield, protein composition, and morphology. Although p22/p18 and Gag colocalize in the cytoplasm, p22/p18 disrupts sites used for VLP assembly. Glutathione S-transferase (GST) affinity pulldowns also suggest that p18 and Gag interact. Therefore, this intrinsic Gag-like restriction factor confers CNC by interfering with VLP assembly and function and expands the strategies used to limit retroelement propagation. IMPORTANCE Retrotransposons dominate the chromosomal landscape in many eukaryotes, can cause mutations by insertion or genome rearrangement, and are evolutionarily related to retroviruses such as HIV. Thus, understanding factors that limit transposition and retroviral replication is fundamentally important. The present work describes a retrotransposon-encoded restriction protein derived from the capsid gene of the yeast Ty1 element that disrupts virus-like particle assembly in a dose-dependent manner. This form of copy number control acts as a molecular rheostat, allowing high levels of retrotransposition when few Ty1 elements are present and inhibiting transposition as copy number increases. Thus, yeast and Ty1 have coevolved a form of copy number control that is beneficial to both "host and parasite." To our knowledge, this is the first Gag-like retrotransposon restriction factor described in the literature and expands the ways in which restriction proteins modulate retroelement replication.
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Affiliation(s)
- Agniva Saha
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Jessica A Mitchell
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Yuri Nishida
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Jonathan E Hildreth
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Joshua A Ariberre
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Wendy V Gilbert
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - David J Garfinkel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
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15
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VanHoute D, Maxwell PH. Extension of Saccharomyces paradoxus chronological lifespan by retrotransposons in certain media conditions is associated with changes in reactive oxygen species. Genetics 2014; 198:531-45. [PMID: 25106655 DOI: 10.1534/genetics.114.168799] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Retrotransposons are mobile DNA elements present throughout eukaryotic genomes that can cause mutations and genome rearrangements when they replicate through reverse transcription. Increased expression and/or mobility of retrotransposons has been correlated with aging in yeast, Caenorhabditis elegans, Drosophila melanogaster, and mammals. The many copies of retrotransposons in humans and various model organisms complicate further pursuit of this relationship. The Saccharomyces cerevisiae Ty1 retrotransposon was introduced into a strain of S. paradoxus that completely lacks retrotransposons to compare chronological lifespans (CLSs) of yeast strains with zero, low, or high Ty1 copy number. Yeast chronological lifespan reflects the progressive loss of cell viability in a nondividing state. Chronological lifespans for the strains were not different in rich medium, but were extended in high Ty1 copy-number strains in synthetic medium and in rich medium containing a low dose of hydroxyurea (HU), an agent that depletes deoxynucleoside triphosphates. Lifespan extension was not strongly correlated with Ty1 mobility or mutation rates for a representative gene. Buffering deoxynucleoside triphosphate levels with threonine supplementation did not substantially affect this lifespan extension, and no substantial differences in cell cycle arrest in the nondividing cells were observed. Lifespan extension was correlated with reduced reactive oxygen species during early stationary phase in high Ty1 copy strains, and antioxidant treatment allowed the zero Ty1 copy strain to live as long as high Ty1 copy-number strains in rich medium with hydroxyurea. This exceptional yeast system has identified an unexpected longevity-promoting role for retrotransposons that may yield novel insights into mechanisms regulating lifespan.
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16
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Arnaiz O, Mathy N, Baudry C, Malinsky S, Aury JM, Denby Wilkes C, Garnier O, Labadie K, Lauderdale BE, Le Mouël A, Marmignon A, Nowacki M, Poulain J, Prajer M, Wincker P, Meyer E, Duharcourt S, Duret L, Bétermier M, Sperling L. The Paramecium germline genome provides a niche for intragenic parasitic DNA: evolutionary dynamics of internal eliminated sequences. PLoS Genet 2012; 8:e1002984. [PMID: 23071448 DOI: 10.1371/journal.pgen.1002984] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 08/09/2012] [Indexed: 12/30/2022] Open
Abstract
Insertions of parasitic DNA within coding sequences are usually deleterious and are generally counter-selected during evolution. Thanks to nuclear dimorphism, ciliates provide unique models to study the fate of such insertions. Their germline genome undergoes extensive rearrangements during development of a new somatic macronucleus from the germline micronucleus following sexual events. In Paramecium, these rearrangements include precise excision of unique-copy Internal Eliminated Sequences (IES) from the somatic DNA, requiring the activity of a domesticated piggyBac transposase, PiggyMac. We have sequenced Paramecium tetraurelia germline DNA, establishing a genome-wide catalogue of ∼45,000 IESs, in order to gain insight into their evolutionary origin and excision mechanism. We obtained direct evidence that PiggyMac is required for excision of all IESs. Homology with known P. tetraurelia Tc1/mariner transposons, described here, indicates that at least a fraction of IESs derive from these elements. Most IES insertions occurred before a recent whole-genome duplication that preceded diversification of the P. aurelia species complex, but IES invasion of the Paramecium genome appears to be an ongoing process. Once inserted, IESs decay rapidly by accumulation of deletions and point substitutions. Over 90% of the IESs are shorter than 150 bp and present a remarkable size distribution with a ∼10 bp periodicity, corresponding to the helical repeat of double-stranded DNA and suggesting DNA loop formation during assembly of a transpososome-like excision complex. IESs are equally frequent within and between coding sequences; however, excision is not 100% efficient and there is selective pressure against IES insertions, in particular within highly expressed genes. We discuss the possibility that ancient domestication of a piggyBac transposase favored subsequent propagation of transposons throughout the germline by allowing insertions in coding sequences, a fraction of the genome in which parasitic DNA is not usually tolerated. Ciliates are unicellular eukaryotes that rearrange their genomes at every sexual generation when a new somatic macronucleus, responsible for gene expression, develops from a copy of the germline micronucleus. In Paramecium, assembly of a functional somatic genome requires precise excision of interstitial DNA segments, the Internal Eliminated Sequences (IES), involving a domesticated piggyBac transposase, PiggyMac. To study IES origin and evolution, we sequenced germline DNA and identified 45,000 IESs. We found that at least some of these unique-copy elements are decayed Tc1/mariner transposons and that IES insertion is likely an ongoing process. After insertion, elements decay rapidly by accumulation of deletions and substitutions. The 93% of IESs shorter than 150 bp display a remarkable size distribution with a periodicity of 10 bp, the helical repeat of double-stranded DNA, consistent with the idea that evolution has only retained IESs that can form a double-stranded DNA loop during assembly of an excision complex. We propose that the ancient domestication of a piggyBac transposase, which provided a precise excision mechanism, enabled transposons to subsequently invade Paramecium coding sequences, a fraction of the genome that does not usually tolerate parasitic DNA.
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17
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Cawley A, Warwicker J. eIF4E-binding protein regulation of mRNAs with differential 5'-UTR secondary structure: a polyelectrostatic model for a component of protein-mRNA interactions. Nucleic Acids Res 2012; 40:7666-75. [PMID: 22718971 PMCID: PMC3439904 DOI: 10.1093/nar/gks511] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Control of translation in eukaryotes is complex, depending on the binding of various factors to mRNAs. Available data for subsets of mRNAs that are translationally up- and down-regulated in yeast eIF4E-binding protein (4E-BP) deletion mutants are coupled with reported mRNA secondary structure measurements to investigate whether 5′-UTR secondary structure varies between the subsets. Genes with up-regulated translational efficiencies in the caf20Δ mutant have relatively high averaged 5′-UTR secondary structure. There is no apparent wide-scale correlation of RNA-binding protein preferences with the increased 5′-UTR secondary structure, leading us to speculate that the secondary structure itself may play a role in differential partitioning of mRNAs between eIF4E/4E-BP repression and eIF4E/eIF4G translation initiation. Both Caf20p and Eap1p contain stretches of positive charge in regions of predicted disorder. Such regions are also present in eIF4G and have been reported to associate with mRNA binding. The pattern of these segments, around the canonical eIF4E-binding motif, varies between each 4E-BP and eIF4G. Analysis of gene ontology shows that yeast proteins containing predicted disordered segments, with positive charge runs, are enriched for nucleic acid binding. We propose that the 4E-BPs act, in part, as differential, flexible, polyelectrostatic scaffolds for mRNAs.
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Affiliation(s)
- Andrew Cawley
- Faculty of Life Sciences, University of Manchester, Manchester Interdisciplinary Biocentre, 131 Princess Street, Manchester M1 7DN, UK
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18
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Amselem J, Cuomo CA, van Kan JAL, Viaud M, Benito EP, Couloux A, Coutinho PM, de Vries RP, Dyer PS, Fillinger S, Fournier E, Gout L, Hahn M, Kohn L, Lapalu N, Plummer KM, Pradier JM, Quévillon E, Sharon A, Simon A, ten Have A, Tudzynski B, Tudzynski P, Wincker P, Andrew M, Anthouard V, Beever RE, Beffa R, Benoit I, Bouzid O, Brault B, Chen Z, Choquer M, Collémare J, Cotton P, Danchin EG, Da Silva C, Gautier A, Giraud C, Giraud T, Gonzalez C, Grossetete S, Güldener U, Henrissat B, Howlett BJ, Kodira C, Kretschmer M, Lappartient A, Leroch M, Levis C, Mauceli E, Neuvéglise C, Oeser B, Pearson M, Poulain J, Poussereau N, Quesneville H, Rascle C, Schumacher J, Ségurens B, Sexton A, Silva E, Sirven C, Soanes DM, Talbot NJ, Templeton M, Yandava C, Yarden O, Zeng Q, Rollins JA, Lebrun MH, Dickman M. Genomic analysis of the necrotrophic fungal pathogens Sclerotinia sclerotiorum and Botrytis cinerea. PLoS Genet 2011; 7:e1002230. [PMID: 21876677 PMCID: PMC3158057 DOI: 10.1371/journal.pgen.1002230] [Citation(s) in RCA: 647] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 06/22/2011] [Indexed: 12/03/2022] Open
Abstract
Sclerotinia sclerotiorum and Botrytis cinerea are closely related necrotrophic plant pathogenic fungi notable for their wide host ranges and environmental persistence. These attributes have made these species models for understanding the complexity of necrotrophic, broad host-range pathogenicity. Despite their similarities, the two species differ in mating behaviour and the ability to produce asexual spores. We have sequenced the genomes of one strain of S. sclerotiorum and two strains of B. cinerea. The comparative analysis of these genomes relative to one another and to other sequenced fungal genomes is provided here. Their 38-39 Mb genomes include 11,860-14,270 predicted genes, which share 83% amino acid identity on average between the two species. We have mapped the S. sclerotiorum assembly to 16 chromosomes and found large-scale co-linearity with the B. cinerea genomes. Seven percent of the S. sclerotiorum genome comprises transposable elements compared to <1% of B. cinerea. The arsenal of genes associated with necrotrophic processes is similar between the species, including genes involved in plant cell wall degradation and oxalic acid production. Analysis of secondary metabolism gene clusters revealed an expansion in number and diversity of B. cinerea-specific secondary metabolites relative to S. sclerotiorum. The potential diversity in secondary metabolism might be involved in adaptation to specific ecological niches. Comparative genome analysis revealed the basis of differing sexual mating compatibility systems between S. sclerotiorum and B. cinerea. The organization of the mating-type loci differs, and their structures provide evidence for the evolution of heterothallism from homothallism. These data shed light on the evolutionary and mechanistic bases of the genetically complex traits of necrotrophic pathogenicity and sexual mating. This resource should facilitate the functional studies designed to better understand what makes these fungi such successful and persistent pathogens of agronomic crops.
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Affiliation(s)
- Joelle Amselem
- Unité de Recherche Génomique – Info, UR1164, INRA, Versailles, France
- Biologie et Gestion des Risques en Agriculture – Champignons Pathogènes des Plantes, UR1290, INRA, Grignon, France
| | - Christina A. Cuomo
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Jan A. L. van Kan
- Laboratory of Phytopathology, Wageningen University, Wageningen, The Netherlands
| | - Muriel Viaud
- Biologie et Gestion des Risques en Agriculture – Champignons Pathogènes des Plantes, UR1290, INRA, Grignon, France
| | - Ernesto P. Benito
- Departamento de Microbiología y Genética, Centro Hispano-Luso de Investigaciones Agrarias, Universidad de Salamanca, Salamanca, Spain
| | | | - Pedro M. Coutinho
- Architecture et Fonction des Macromolécules Biologiques, UMR6098, CNRS – Université de la Méditerranée et Université de Provence, Marseille, France
| | - Ronald P. de Vries
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht, The Netherlands
- CBS-KNAW Fungal Biodiversity Centre, Utrecht, The Netherlands
| | - Paul S. Dyer
- School of Biology, University of Nottingham, Nottingham, United Kingdom
| | - Sabine Fillinger
- Biologie et Gestion des Risques en Agriculture – Champignons Pathogènes des Plantes, UR1290, INRA, Grignon, France
| | - Elisabeth Fournier
- Biologie et Gestion des Risques en Agriculture – Champignons Pathogènes des Plantes, UR1290, INRA, Grignon, France
- Biologie et Génétique des Interactions Plante-Parasite, CIRAD – INRA – SupAgro, Montpellier, France
| | - Lilian Gout
- Biologie et Gestion des Risques en Agriculture – Champignons Pathogènes des Plantes, UR1290, INRA, Grignon, France
| | - Matthias Hahn
- Faculty of Biology, Kaiserslautern University, Kaiserslautern, Germany
| | - Linda Kohn
- Biology Department, University of Toronto, Mississauga, Canada
| | - Nicolas Lapalu
- Unité de Recherche Génomique – Info, UR1164, INRA, Versailles, France
| | - Kim M. Plummer
- Botany Department, La Trobe University, Melbourne, Australia
| | - Jean-Marc Pradier
- Biologie et Gestion des Risques en Agriculture – Champignons Pathogènes des Plantes, UR1290, INRA, Grignon, France
| | - Emmanuel Quévillon
- Unité de Recherche Génomique – Info, UR1164, INRA, Versailles, France
- Laboratoire de Génomique Fonctionnelle des Champignons Pathogènes de Plantes, UMR5240, Université de Lyon 1 – CNRS – BAYER S.A.S., Lyon, France
| | - Amir Sharon
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv, Israel
| | - Adeline Simon
- Biologie et Gestion des Risques en Agriculture – Champignons Pathogènes des Plantes, UR1290, INRA, Grignon, France
| | - Arjen ten Have
- Instituto de Investigaciones Biologicas – CONICET, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
| | - Bettina Tudzynski
- Molekularbiologie und Biotechnologie der Pilze, Institut für Biologie und Biotechnologie der Pflanzen, Münster, Germany
| | - Paul Tudzynski
- Molekularbiologie und Biotechnologie der Pilze, Institut für Biologie und Biotechnologie der Pflanzen, Münster, Germany
| | | | - Marion Andrew
- Biology Department, University of Toronto, Mississauga, Canada
| | | | | | - Rolland Beffa
- Laboratoire de Génomique Fonctionnelle des Champignons Pathogènes de Plantes, UMR5240, Université de Lyon 1 – CNRS – BAYER S.A.S., Lyon, France
| | - Isabelle Benoit
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht, The Netherlands
| | - Ourdia Bouzid
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht, The Netherlands
| | - Baptiste Brault
- Unité de Recherche Génomique – Info, UR1164, INRA, Versailles, France
- Biologie et Gestion des Risques en Agriculture – Champignons Pathogènes des Plantes, UR1290, INRA, Grignon, France
| | - Zehua Chen
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Mathias Choquer
- Biologie et Gestion des Risques en Agriculture – Champignons Pathogènes des Plantes, UR1290, INRA, Grignon, France
- Laboratoire de Génomique Fonctionnelle des Champignons Pathogènes de Plantes, UMR5240, Université de Lyon 1 – CNRS – BAYER S.A.S., Lyon, France
| | - Jérome Collémare
- Laboratory of Phytopathology, Wageningen University, Wageningen, The Netherlands
- Laboratoire de Génomique Fonctionnelle des Champignons Pathogènes de Plantes, UMR5240, Université de Lyon 1 – CNRS – BAYER S.A.S., Lyon, France
| | - Pascale Cotton
- Laboratoire de Génomique Fonctionnelle des Champignons Pathogènes de Plantes, UMR5240, Université de Lyon 1 – CNRS – BAYER S.A.S., Lyon, France
| | - Etienne G. Danchin
- Interactions Biotiques et Santé Plantes, UMR5240, INRA – Université de Nice Sophia-Antipolis – CNRS, Sophia-Antipolis, France
| | | | - Angélique Gautier
- Biologie et Gestion des Risques en Agriculture – Champignons Pathogènes des Plantes, UR1290, INRA, Grignon, France
| | - Corinne Giraud
- Biologie et Gestion des Risques en Agriculture – Champignons Pathogènes des Plantes, UR1290, INRA, Grignon, France
| | - Tatiana Giraud
- Laboratoire d'Ecologie, Systématique et Evolution, Université Paris-Sud – CNRS – AgroParisTech, Orsay, France
| | - Celedonio Gonzalez
- Departamento de Bioquímica y Biología Molecular, Universidad de La Laguna, Tenerife, Spain
| | - Sandrine Grossetete
- Laboratoire de Génomique Fonctionnelle des Champignons Pathogènes de Plantes, UMR5240, Université de Lyon 1 – CNRS – BAYER S.A.S., Lyon, France
| | - Ulrich Güldener
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Bioinformatics and Systems Biology, Neuherberg, Germany
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques, UMR6098, CNRS – Université de la Méditerranée et Université de Provence, Marseille, France
| | | | - Chinnappa Kodira
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | | | - Anne Lappartient
- Laboratoire de Génomique Fonctionnelle des Champignons Pathogènes de Plantes, UMR5240, Université de Lyon 1 – CNRS – BAYER S.A.S., Lyon, France
| | - Michaela Leroch
- Faculty of Biology, Kaiserslautern University, Kaiserslautern, Germany
| | - Caroline Levis
- Biologie et Gestion des Risques en Agriculture – Champignons Pathogènes des Plantes, UR1290, INRA, Grignon, France
| | - Evan Mauceli
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Cécile Neuvéglise
- Biologie Intégrative du Métabolisme Lipidique Microbien, UMR1319, INRA – Micalis – AgroParisTech, Thiverval-Grignon, France
| | - Birgitt Oeser
- Molekularbiologie und Biotechnologie der Pilze, Institut für Biologie und Biotechnologie der Pflanzen, Münster, Germany
| | - Matthew Pearson
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Julie Poulain
- GENOSCOPE, Centre National de Séquençage, Evry, France
| | - Nathalie Poussereau
- Laboratoire de Génomique Fonctionnelle des Champignons Pathogènes de Plantes, UMR5240, Université de Lyon 1 – CNRS – BAYER S.A.S., Lyon, France
| | - Hadi Quesneville
- Unité de Recherche Génomique – Info, UR1164, INRA, Versailles, France
| | - Christine Rascle
- Laboratoire de Génomique Fonctionnelle des Champignons Pathogènes de Plantes, UMR5240, Université de Lyon 1 – CNRS – BAYER S.A.S., Lyon, France
| | - Julia Schumacher
- Molekularbiologie und Biotechnologie der Pilze, Institut für Biologie und Biotechnologie der Pflanzen, Münster, Germany
| | | | - Adrienne Sexton
- School of Botany, University of Melbourne, Melbourne, Australia
| | - Evelyn Silva
- Fundacion Ciencia para la Vida and Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago, Chile
| | - Catherine Sirven
- Laboratoire de Génomique Fonctionnelle des Champignons Pathogènes de Plantes, UMR5240, Université de Lyon 1 – CNRS – BAYER S.A.S., Lyon, France
| | - Darren M. Soanes
- School of Biosciences, University of Exeter, Exeter, United Kingdom
| | | | - Matt Templeton
- Plant and Food Research, Mt. Albert Research Centre, Auckland, New Zealand
| | - Chandri Yandava
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Oded Yarden
- Department of Plant Pathology and Microbiology, Hebrew University Jerusalem, Rehovot, Israel
| | - Qiandong Zeng
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Jeffrey A. Rollins
- Department of Plant Pathology, University of Florida, Gainesville, Florida, United States of America
| | - Marc-Henri Lebrun
- Unité de Recherche Génomique – Info, UR1164, INRA, Versailles, France
- Biologie et Gestion des Risques en Agriculture – Champignons Pathogènes des Plantes, UR1290, INRA, Grignon, France
- Laboratoire de Génomique Fonctionnelle des Champignons Pathogènes de Plantes, UMR5240, Université de Lyon 1 – CNRS – BAYER S.A.S., Lyon, France
| | - Marty Dickman
- Institute for Plant Genomics and Biotechnology, Borlaug Genomics and Bioinformatics Center, Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas, United States of America
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19
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Abstract
Yeast and mammalian genomes are replete with nearly identical copies of long dispersed repeats in the form of retrotransposons. Mechanisms clearly exist to maintain genome structure in the face of potential rearrangement between the dispersed repeats, but the nature of this machinery is poorly understood. Here we describe a series of distinct "retrotransposon overdose" (RO) lineages in which the number of Ty1 elements in the Saccharomyces cerevisiae genome has been increased by as much as 10 fold. Although these RO strains are remarkably normal in growth rate, they demonstrate an intrinsic supersensitivity to DNA-damaging agents. We describe the identification of mutants in the DNA replication pathway that enhance this RO-specific DNA damage supersensitivity by promoting ectopic recombination between Ty1 elements. Abrogation of normal DNA replication leads to rampant genome instability primarily in the form of chromosomal aberrations and confirms the central role of DNA replication accuracy in the stabilization of repetitive DNA.
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20
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Abstract
The genomes of unicellular species, particularly prokaryotes, are greatly reduced in size and simplified in terms of gene structure relative to those of multicellular eukaryotes. Arguments proposed to explain this disparity include selection for metabolic efficiency and elevated rates of deletion in microbes, but the evidence in support of these hypotheses is at best equivocal. An alternative explanation based on fundamental population-genetic principles is proposed here. By increasing the mutational target sizes of associated genes, most forms of nonfunctional DNA are opposed by weak selection. Free-living microbial species have elevated effective population sizes, and the consequent reduction in the power of random genetic drift appears to be sufficient to enable natural selection to inhibit the accumulation of excess DNA. This hypothesis provides a potentially unifying explanation for the continuity in genomic scaling from prokaryotes to multicellular eukaryotes, the divergent patterns of mitochondrial evolution in animals and land plants, and various aspects of genomic modification in microbial endosymbionts.
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Affiliation(s)
- Michael Lynch
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA.
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21
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Garfinkel DJ, Stefanisko KM, Nyswaner KM, Moore SP, Oh J, Hughes SH. Retrotransposon suicide: formation of Ty1 circles and autointegration via a central DNA flap. J Virol 2006; 80:11920-34. [PMID: 17005648 PMCID: PMC1676259 DOI: 10.1128/jvi.01483-06] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Despite their evolutionary distance, the Saccharomyces cerevisiae retrotransposon Ty1 and retroviruses use similar strategies for replication, integration, and interactions with their hosts. Here we examine the formation of circular Ty1 DNA, which is comparable to the dead-end circular products that arise during retroviral infection. Appreciable levels of circular Ty1 DNA are present with one-long terminal repeat (LTR) circles and deleted circles comprising major classes, while two-LTR circles are enriched when integration is defective. One-LTR circles persist when homologous recombination pathways are blocked by mutation, suggesting that they result from reverse transcription. Ty1 autointegration events readily occur, and many are coincident with and dependent upon DNA flap structures that result from DNA synthesis initiated at the central polypurine tract. These results suggest that Ty1-specific mechanisms minimize copy number and raise the possibility that special DNA structures are a targeting determinant.
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Affiliation(s)
- David J Garfinkel
- National Cancer Institute, P.O. Box B, Frederick, MD 21702-1201, USA.
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Current awareness on yeast. Yeast 2005; 22:1249-56. [PMID: 16320446 DOI: 10.1002/yea.1170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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