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Hoguin A, Yang F, Groisillier A, Bowler C, Genovesio A, Ait-Mohamed O, Vieira FRJ, Tirichine L. The model diatom Phaeodactylum tricornutum provides insights into the diversity and function of microeukaryotic DNA methyltransferases. Commun Biol 2023; 6:253. [PMID: 36894681 PMCID: PMC9998398 DOI: 10.1038/s42003-023-04629-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 02/27/2023] [Indexed: 03/11/2023] Open
Abstract
Cytosine methylation is an important epigenetic mark involved in the transcriptional control of transposable elements in mammals, plants and fungi. The Stramenopiles-Alveolate-Rhizaria (SAR) lineages are a major group of ecologically important marine microeukaryotes, including the phytoplankton groups diatoms and dinoflagellates. However, little is known about their DNA methyltransferase diversity. Here, we performed an in-silico analysis of DNA methyltransferases found in marine microeukaryotes and showed that they encode divergent DNMT3, DNMT4, DNMT5 and DNMT6 enzymes. Furthermore, we found three classes of enzymes within the DNMT5 family. Using a CRISPR/Cas9 strategy we demonstrated that the loss of the DNMT5a gene correlates with a global depletion of DNA methylation and overexpression of young transposable elements in the model diatom Phaeodactylum tricornutum. The study provides a view of the structure and function of a DNMT family in the SAR supergroup using an attractive model species.
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Affiliation(s)
- Antoine Hoguin
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Feng Yang
- Nantes Université, CNRS, US2B, UMR 6286, F-44000, Nantes, France
| | | | - Chris Bowler
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
| | - Auguste Genovesio
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France
| | - Ouardia Ait-Mohamed
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France.
| | - Fabio Rocha Jimenez Vieira
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005, Paris, France.
- Laboratory of Computational and Quantitative Biology-LCQB - UMR 7238 CNRS-Sorbonne Université. Institut de Biologie Paris Seine, 75005, Paris, France.
| | - Leila Tirichine
- Nantes Université, CNRS, US2B, UMR 6286, F-44000, Nantes, France.
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2
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Lelandais G, Remy D, Malagnac F, Grognet P. New insights into genome annotation in Podospora anserina through re-exploiting multiple RNA-seq data. BMC Genomics 2022; 23:859. [PMID: 36581831 PMCID: PMC9801653 DOI: 10.1186/s12864-022-09085-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 12/16/2022] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Publicly available RNA-seq datasets are often underused although being helpful to improve functional annotation of eukaryotic genomes. This is especially true for filamentous fungi genomes which structure differs from most well annotated yeast genomes. Podospora anserina is a filamentous fungal model, which genome has been sequenced and annotated in 2008. Still, the current annotation lacks information about cis-regulatory elements, including promoters, transcription starting sites and terminators, which are instrumental to integrate epigenomic features into global gene regulation strategies. RESULTS Here we took advantage of 37 RNA-seq experiments that were obtained in contrasted developmental and physiological conditions, to complete the functional annotation of P. anserina genome. Out of the 10,800 previously annotated genes, 5'UTR and 3'UTR were defined for 7554, among which, 3328 showed differential transcriptional signal starts and/or transcriptional end sites. In addition, alternative splicing events were detected for 2350 genes, mostly due alternative 3'splice sites and 1732 novel transcriptionally active regions (nTARs) in unannotated regions were identified. CONCLUSIONS Our study provides a comprehensive genome-wide functional annotation of P. anserina genome, including chromatin features, cis-acting elements such as UTRs, alternative splicing events and transcription of non-coding regions. These new findings will likely improve our understanding of gene regulation strategies in compact genomes, such as those of filamentous fungi. Characterization of alternative transcripts and nTARs paves the way to the discovery of putative new genes, alternative peptides or regulatory non-coding RNAs.
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Affiliation(s)
- Gaëlle Lelandais
- grid.457334.20000 0001 0667 2738Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Damien Remy
- grid.457334.20000 0001 0667 2738Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Fabienne Malagnac
- grid.457334.20000 0001 0667 2738Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Pierre Grognet
- grid.457334.20000 0001 0667 2738Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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3
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Bind S, Bind S, Sharma AK, Chaturvedi P. Epigenetic Modification: A Key Tool for Secondary Metabolite Production in Microorganisms. Front Microbiol 2022; 13:784109. [PMID: 35495688 PMCID: PMC9043899 DOI: 10.3389/fmicb.2022.784109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
Microorganisms are stupendous source of secondary metabolites, having significant pharmaceutical and industrial importance. Genome mining has led to the detection of several cryptic metabolic pathways in the natural producer of secondary metabolites (SMs) such as actinobacteria and fungi. Production of these bioactive compounds in considerable amount is, however, somewhat challenging. This led to the search of using epigenetics as a key mechanism to alter the expression of genes that encode the SMs toward higher production in microorganisms. Epigenetics is defined as any heritable change without involving the changes in the underlying DNA sequences. Epigenetic modifications include chromatin remodeling by histone posttranslational modifications, DNA methylation, and RNA interference. Biosynthetic gene cluster for SMs remains in heterochromatin state in which the transcription of constitutive gene is regulated by epigenetic modification. Therefore, small-molecule epigenetic modifiers, which promote changes in the structure of chromatin, could control the expression of silent genes and may be rationally employed for discovery of novel bioactive compounds. This review article focuses on the types of epigenetic modifications and their impact on gene expression for enhancement of SM production in microorganisms.
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Affiliation(s)
- Sudha Bind
- Department of Biological Sciences, CBSH, G. B. Pant University of Agriculture & Technology, Pantnagar, India
| | - Sandhya Bind
- Department of Biological Sciences, CBSH, G. B. Pant University of Agriculture & Technology, Pantnagar, India
| | - A K Sharma
- Department of Biological Sciences, CBSH, G. B. Pant University of Agriculture & Technology, Pantnagar, India
| | - Preeti Chaturvedi
- Department of Biological Sciences, CBSH, G. B. Pant University of Agriculture & Technology, Pantnagar, India
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Tini F, Beccari G, Marconi G, Porceddu A, Sulyok M, Gardiner DM, Albertini E, Covarelli L. Identification of Putative Virulence Genes by DNA Methylation Studies in the Cereal Pathogen Fusarium graminearum. Cells 2021; 10:cells10051192. [PMID: 34068122 PMCID: PMC8152758 DOI: 10.3390/cells10051192] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/03/2021] [Accepted: 05/10/2021] [Indexed: 01/17/2023] Open
Abstract
DNA methylation mediates organisms’ adaptations to environmental changes in a wide range of species. We investigated if a such a strategy is also adopted by Fusarium graminearum in regulating virulence toward its natural hosts. A virulent strain of this fungus was consecutively sub-cultured for 50 times (once a week) on potato dextrose agar. To assess the effect of subculturing on virulence, wheat seedlings and heads (cv. A416) were inoculated with subcultures (SC) 1, 23, and 50. SC50 was also used to re-infect (three times) wheat heads (SC50×3) to restore virulence. In vitro conidia production, colonies growth and secondary metabolites production were also determined for SC1, SC23, SC50, and SC50×3. Seedling stem base and head assays revealed a virulence decline of all subcultures, whereas virulence was restored in SC50×3. The same trend was observed in conidia production. The DNA isolated from SC50 and SC50×3 was subject to a methylation content-sensitive enzyme and double-digest, restriction-site-associated DNA technique (ddRAD-MCSeEd). DNA methylation analysis indicated 1024 genes, whose methylation levels changed in response to the inoculation on a healthy host after subculturing. Several of these genes are already known to be involved in virulence by functional analysis. These results demonstrate that the physiological shifts following sub-culturing have an impact on genomic DNA methylation levels and suggest that the ddRAD-MCSeEd approach can be an important tool for detecting genes potentially related to fungal virulence.
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Affiliation(s)
- Francesco Tini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy; (F.T.); (G.B.); (E.A.); (L.C.)
| | - Giovanni Beccari
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy; (F.T.); (G.B.); (E.A.); (L.C.)
| | - Gianpiero Marconi
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy; (F.T.); (G.B.); (E.A.); (L.C.)
- Correspondence:
| | - Andrea Porceddu
- Department of Agriculture, University of Sassari, Viale Italia, 39a, 07100 Sassari, Italy;
| | - Micheal Sulyok
- Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Applied Life Sciences, Vienna (BOKU), Konrad Lorenz Strasse, 20, A-3430 Tulln, Austria;
| | - Donald M. Gardiner
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, 306 Carmody Road, St Lucia, QLD 4067, Australia;
| | - Emidio Albertini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy; (F.T.); (G.B.); (E.A.); (L.C.)
| | - Lorenzo Covarelli
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy; (F.T.); (G.B.); (E.A.); (L.C.)
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5
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Möller M, Habig M, Lorrain C, Feurtey A, Haueisen J, Fagundes WC, Alizadeh A, Freitag M, Stukenbrock EH. Recent loss of the Dim2 DNA methyltransferase decreases mutation rate in repeats and changes evolutionary trajectory in a fungal pathogen. PLoS Genet 2021; 17:e1009448. [PMID: 33750960 PMCID: PMC8016269 DOI: 10.1371/journal.pgen.1009448] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 04/01/2021] [Accepted: 02/26/2021] [Indexed: 01/04/2023] Open
Abstract
DNA methylation is found throughout all domains of life, yet the extent and function of DNA methylation differ among eukaryotes. Strains of the plant pathogenic fungus Zymoseptoria tritici appeared to lack cytosine DNA methylation (5mC) because gene amplification followed by Repeat-Induced Point mutation (RIP) resulted in the inactivation of the dim2 DNA methyltransferase gene. 5mC is, however, present in closely related sister species. We demonstrate that inactivation of dim2 occurred recently as some Z. tritici isolates carry a functional dim2 gene. Moreover, we show that dim2 inactivation occurred by a different path than previously hypothesized. We mapped the genome-wide distribution of 5mC in strains with or without functional dim2 alleles. Presence of functional dim2 correlates with high levels of 5mC in transposable elements (TEs), suggesting a role in genome defense. We identified low levels of 5mC in strains carrying non-functional dim2 alleles, suggesting that 5mC is maintained over time, presumably by an active Dnmt5 DNA methyltransferase. Integration of a functional dim2 allele in strains with mutated dim2 restored normal 5mC levels, demonstrating de novo cytosine methylation activity of Dim2. To assess the importance of 5mC for genome evolution, we performed an evolution experiment, comparing genomes of strains with high levels of 5mC to genomes of strains lacking functional dim2. We found that presence of a functional dim2 allele alters nucleotide composition by promoting C to T transitions (C→T) specifically at CpA (CA) sites during mitosis, likely contributing to TE inactivation. Our results show that 5mC density at TEs is a polymorphic trait in Z. tritici populations that can impact genome evolution.
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Affiliation(s)
- Mareike Möller
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Michael Habig
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Cécile Lorrain
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Alice Feurtey
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Janine Haueisen
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Wagner C. Fagundes
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Alireza Alizadeh
- Department of Plant Protection, Faculty of Agriculture, Azarbaijan Shahid Madani University, Tabriz, Iran
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, United States of America
| | - Eva H. Stukenbrock
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
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6
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Nai YS, Huang YC, Yen MR, Chen PY. Diversity of Fungal DNA Methyltransferases and Their Association With DNA Methylation Patterns. Front Microbiol 2021; 11:616922. [PMID: 33552027 PMCID: PMC7862722 DOI: 10.3389/fmicb.2020.616922] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/28/2020] [Indexed: 11/24/2022] Open
Abstract
DNA methyltransferases (DNMTs) are a group of proteins that catalyze DNA methylation by transferring a methyl group to DNA. The genetic variation in DNMTs results in differential DNA methylation patterns associated with various biological processes. In fungal species, DNMTs and their DNA methylation profiles were found to be very diverse and have gained many research interests. We reviewed fungal DNMTs in terms of their biological functions, protein domain structures, and their associated epigenetic regulations compared to those known in plant and animal systems. In addition, we summarized recent reports on potential RNA-directed DNA methylation (RdDM) related to DNMT5 in fungi. We surveyed up to 40 fungal species with published genome-wide DNA methylation profiles (methylomes) and presented the associations between the specific patterns of fungal DNA methylation and their DNMTs based on a phylogenetic tree of protein domain structures. For example, the main DNMTs in Basidiomycota, DNMT1 with RFD domain + DNMT5, contributing to CG methylation preference, were distinct from RID + Dim-2 in Ascomycota, resulting in a non-CG methylation preference. Lastly, we revealed that the dynamic methylation involved in fungal life stage changes was particularly low in mycelium and DNA methylation was preferentially located in transposable elements (TEs). This review comprehensively discussed fungal DNMTs and methylomes and their connection with fungal development and taxonomy to present the diverse usages of DNA methylation in fungal genomes.
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Affiliation(s)
- Yu-Shin Nai
- Department of Entomology, National Chung Hsing University, Taichung, Taiwan.,Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Chun Huang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.,Bioinformatics Program, Taiwan International Graduate Program, National Taiwan University, Taipei, Taiwan.,Bioinformatics Program, Institute of Information Science, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
| | - Ming-Ren Yen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Pao-Yang Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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7
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The Pattern and Function of DNA Methylation in Fungal Plant Pathogens. Microorganisms 2020; 8:microorganisms8020227. [PMID: 32046339 PMCID: PMC7074731 DOI: 10.3390/microorganisms8020227] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/06/2020] [Accepted: 02/06/2020] [Indexed: 01/05/2023] Open
Abstract
To successfully infect plants and trigger disease, fungal plant pathogens use various strategies that are dependent on characteristics of their biology and genomes. Although pathogenic fungi are different from animals and plants in the genomic heritability, sequence feature, and epigenetic modification, an increasing number of phytopathogenic fungi have been demonstrated to share DNA methyltransferases (MTases) responsible for DNA methylation with animals and plants. Fungal plant pathogens predominantly possess four types of DNA MTase homologs, including DIM-2, DNMT1, DNMT5, and RID. Numerous studies have indicated that DNA methylation in phytopathogenic fungi mainly distributes in transposable elements (TEs), gene promoter regions, and the repetitive DNA sequences. As an important and heritable epigenetic modification, DNA methylation is associated with silencing of gene expression and transposon, and it is responsible for a wide range of biological phenomena in fungi. This review highlights the relevant reports and insights into the important roles of DNA methylation in the modulation of development, pathogenicity, and secondary metabolism of fungal plant pathogens. Recent evidences prove that there are massive links between DNA and histone methylation in fungi, and they commonly regulate fungal development and mycotoxin biosynthesis.
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8
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Mazur AK, Nguyen TS, Gladyshev E. Direct Homologous dsDNA-dsDNA Pairing: How, Where, and Why? J Mol Biol 2019; 432:737-744. [PMID: 31726060 DOI: 10.1016/j.jmb.2019.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/22/2019] [Accepted: 11/05/2019] [Indexed: 10/25/2022]
Abstract
The ability of homologous chromosomes (or selected chromosomal loci) to pair specifically in the apparent absence of DNA breakage and recombination represents a prominent feature of eukaryotic biology. The mechanism of homology recognition at the basis of such recombination-independent pairing has remained elusive. A number of studies have supported the idea that sequence homology can be sensed between intact DNA double helices in vivo. In particular, recent analyses of the two silencing phenomena in fungi, known as "repeat-induced point mutation" (RIP) and "meiotic silencing by unpaired DNA" (MSUD), have provided genetic evidence for the existence of the direct homologous dsDNA-dsDNA pairing. Both RIP and MSUD likely rely on the same search strategy, by which dsDNA segments are matched as arrays of interspersed base-pair triplets. This process is general and very efficient, yet it proceeds normally without the RecA/Rad51/Dmc1 proteins. Further studies of RIP and MSUD may yield surprising insights into the function of DNA in the cell.
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Affiliation(s)
- Alexey K Mazur
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 Rue Pierre et Marie Curie, F-75005 Paris, France; Group Fungal Epigenomics, Department of Mycology, Institut Pasteur, Paris 75015, France; Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Tinh-Suong Nguyen
- Group Fungal Epigenomics, Department of Mycology, Institut Pasteur, Paris 75015, France
| | - Eugene Gladyshev
- Group Fungal Epigenomics, Department of Mycology, Institut Pasteur, Paris 75015, France.
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9
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The Parauncinula polyspora Draft Genome Provides Insights into Patterns of Gene Erosion and Genome Expansion in Powdery Mildew Fungi. mBio 2019; 10:mBio.01692-19. [PMID: 31551331 PMCID: PMC6759760 DOI: 10.1128/mbio.01692-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Powdery mildew fungi are widespread and agronomically relevant phytopathogens causing major yield losses. Their genomes have disproportionately large numbers of mobile genetic elements, and they have experienced a significant loss of highly conserved fungal genes. In order to learn more about the evolutionary history of this fungal group, we explored the genome of an Asian oak tree pathogen, Parauncinula polyspora, a species that diverged early during evolution from the remaining powdery mildew fungi. We found that the P. polyspora draft genome is comparatively compact, has a low number of protein-coding genes, and, despite the absence of a dedicated genome defense system, lacks the massive proliferation of repetitive sequences. Based on these findings, we infer an evolutionary trajectory that shaped the genomes of powdery mildew fungi. Due to their comparatively small genome size and short generation time, fungi are exquisite model systems to study eukaryotic genome evolution. Powdery mildew fungi present an exceptional case because of their strict host dependency (termed obligate biotrophy) and the atypical size of their genomes (>100 Mb). This size expansion is largely due to the pervasiveness of transposable elements on 70% of the genome and is associated with the loss of multiple conserved ascomycete genes required for a free-living lifestyle. To date, little is known about the mechanisms that drove these changes, and information on ancestral powdery mildew genomes is lacking. We report genome analysis of the early-diverged and exclusively sexually reproducing powdery mildew fungus Parauncinula polyspora, which we performed on the basis of a natural leaf epiphytic metapopulation sample. In contrast to other sequenced species of this taxonomic group, the assembled P. polyspora draft genome is surprisingly small (<30 Mb), has a higher content of conserved ascomycete genes, and is sparsely equipped with transposons (<10%), despite the conserved absence of a common defense mechanism involved in constraining repetitive elements. We speculate that transposable element spread might have been limited by this pathogen’s unique reproduction strategy and host features and further hypothesize that the loss of conserved ascomycete genes may promote the evolutionary isolation and host niche specialization of powdery mildew fungi. Limitations associated with this evolutionary trajectory might have been in part counteracted by the evolution of plastic, transposon-rich genomes and/or the expansion of gene families encoding secreted virulence proteins.
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10
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Schmitz RJ, Lewis ZA, Goll MG. DNA Methylation: Shared and Divergent Features across Eukaryotes. Trends Genet 2019; 35:818-827. [PMID: 31399242 DOI: 10.1016/j.tig.2019.07.007] [Citation(s) in RCA: 121] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/01/2019] [Accepted: 07/15/2019] [Indexed: 02/02/2023]
Abstract
Chemical modification of nucleotide bases in DNA provides one mechanism for conveying information in addition to the genetic code. 5-methylcytosine (5mC) represents the most common chemically modified base in eukaryotic genomes. Sometimes referred to simply as DNA methylation, in eukaryotes 5mC is most prevalent at CpG dinucleotides and is frequently associated with transcriptional repression of transposable elements. However, 5mC levels and distributions are variable across phylogenies, and emerging evidence suggests that the functions of DNA methylation may be more diverse and complex than was previously appreciated. We summarize the current understanding of DNA methylation profiles and functions in different eukaryotic lineages.
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Affiliation(s)
- Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Zachary A Lewis
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Mary G Goll
- Department of Genetics, University of Georgia, Athens, GA 30602, USA.
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11
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Grognet P, Timpano H, Carlier F, Aït-Benkhali J, Berteaux-Lecellier V, Debuchy R, Bidard F, Malagnac F. A RID-like putative cytosine methyltransferase homologue controls sexual development in the fungus Podospora anserina. PLoS Genet 2019; 15:e1008086. [PMID: 31412020 PMCID: PMC6709928 DOI: 10.1371/journal.pgen.1008086] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 08/26/2019] [Accepted: 07/15/2019] [Indexed: 11/18/2022] Open
Abstract
DNA methyltransferases are ubiquitous enzymes conserved in bacteria, plants and opisthokonta. These enzymes, which methylate cytosines, are involved in numerous biological processes, notably development. In mammals and higher plants, methylation patterns established and maintained by the cytosine DNA methyltransferases (DMTs) are essential to zygotic development. In fungi, some members of an extensively conserved fungal-specific DNA methyltransferase class are both mediators of the Repeat Induced Point mutation (RIP) genome defense system and key players of sexual reproduction. Yet, no DNA methyltransferase activity of these purified RID (RIP deficient) proteins could be detected in vitro. These observations led us to explore how RID-like DNA methyltransferase encoding genes would play a role during sexual development of fungi showing very little genomic DNA methylation, if any. To do so, we used the model ascomycete fungus Podospora anserina. We identified the PaRid gene, encoding a RID-like DNA methyltransferase and constructed knocked-out ΔPaRid defective mutants. Crosses involving P. anserina ΔPaRid mutants are sterile. Our results show that, although gametes are readily formed and fertilization occurs in a ΔPaRid background, sexual development is blocked just before the individualization of the dikaryotic cells leading to meiocytes. Complementation of ΔPaRid mutants with ectopic alleles of PaRid, including GFP-tagged, point-mutated and chimeric alleles, demonstrated that the catalytic motif of the putative PaRid methyltransferase is essential to ensure proper sexual development and that the expression of PaRid is spatially and temporally restricted. A transcriptomic analysis performed on mutant crosses revealed an overlap of the PaRid-controlled genetic network with the well-known mating-types gene developmental pathway common to an important group of fungi, the Pezizomycotina.
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Affiliation(s)
- Pierre Grognet
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris‐Saclay, France
| | - Hélène Timpano
- Université Paris-Sud, Institut de Génétique et Microbiologie UMR8621, Orsay, France, CNRS, Institut de Génétique et Microbiologie UMR8621, Orsay, France
| | - Florian Carlier
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris‐Saclay, France
| | - Jinane Aït-Benkhali
- Université Paris-Sud, Institut de Génétique et Microbiologie UMR8621, Orsay, France, CNRS, Institut de Génétique et Microbiologie UMR8621, Orsay, France
| | | | - Robert Debuchy
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris‐Saclay, France
| | - Frédérique Bidard
- Université Paris-Sud, Institut de Génétique et Microbiologie UMR8621, Orsay, France, CNRS, Institut de Génétique et Microbiologie UMR8621, Orsay, France
| | - Fabienne Malagnac
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris‐Saclay, France
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Collemare J, Seidl MF. Chromatin-dependent regulation of secondary metabolite biosynthesis in fungi: is the picture complete? FEMS Microbiol Rev 2019; 43:591-607. [PMID: 31301226 PMCID: PMC8038932 DOI: 10.1093/femsre/fuz018] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Accepted: 06/18/2019] [Indexed: 01/07/2023] Open
Abstract
Fungal secondary metabolites are small molecules that exhibit diverse biological activities exploited in medicine, industry and agriculture. Their biosynthesis is governed by co-expressed genes that often co-localize in gene clusters. Most of these secondary metabolite gene clusters are inactive under laboratory conditions, which is due to a tight transcriptional regulation. Modifications of chromatin, the complex of DNA and histone proteins influencing DNA accessibility, play an important role in this regulation. However, tinkering with well-characterised chemical and genetic modifications that affect chromatin alters the expression of only few biosynthetic gene clusters, and thus the regulation of the vast majority of biosynthetic pathways remains enigmatic. In the past, attempts to activate silent gene clusters in fungi mainly focused on histone acetylation and methylation, while in other eukaryotes many other post-translational modifications are involved in transcription regulation. Thus, how chromatin regulates the expression of gene clusters remains a largely unexplored research field. In this review, we argue that focusing on only few well-characterised chromatin modifications is significantly hampering our understanding of the chromatin-based regulation of biosynthetic gene clusters. Research on underexplored chromatin modifications and on the interplay between different modifications is timely to fully explore the largely untapped reservoir of fungal secondary metabolites.
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Affiliation(s)
| | - Michael F Seidl
- Corresponding author: Theoretical Biology and Bioinformatics, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands. E-mail: ; Present address: Theoretical Biology and Bioinformatics, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
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Partition of Repeat-Induced Point Mutations Reveals Structural Aspects of Homologous DNA-DNA Pairing. Biophys J 2018; 115:605-615. [PMID: 30086830 DOI: 10.1016/j.bpj.2018.06.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/28/2018] [Indexed: 11/21/2022] Open
Abstract
In some fungi, a premeiotic process known as repeat-induced point mutation (RIP) can accurately identify and mutate nearly all gene-sized DNA repeats present in the haploid germline nuclei. Studies in Neurospora crassa have suggested that RIP detects sequence homology directly between intact DNA double helices, without strand separation and without the participation of RecA-like proteins. Those studies used the aggregated number of RIP mutations as a simple quantitative measure of RIP activity. Additional structural information about homologous DNA-DNA pairing during RIP can be extracted by analyzing spatial distributions of RIP mutations converted into profiles of partitioned RIP propensity (PRP). Further analysis shows that PRP is strongly affected by the topological configuration and the relative positioning of the participating DNA segments. Most notably, pairs of closely positioned repeats produce very distinct PRP profiles depending on whether these repeats are present in the direct or the inverted orientation. Such an effect can be attributed to a topology-dependent redistribution of the supercoiling stress created by the predicted limited untwisting of the DNA segments during pairing. This and other results raise a possibility that such pairing-induced fluctuations in DNA supercoiling can modulate the overall structure and properties of repetitive DNA. Such effects can be particularly strong in the context of long tandem-repeat arrays that are typically present in the pericentromeric and centromeric regions of chromosomes in many species of plants, fungi, and animals, including humans.
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Abstract
Transposable elements have colonized the genomes of nearly all organisms, including fungi. Although transposable elements may sometimes provide beneficial functions to their hosts their overall impact is considered deleterious. As a result, the activity of transposable elements needs to be counterbalanced by the host genome defenses. In fungi, the primary genome defense mechanisms include repeat-induced point mutation (RIP) and methylation induced premeiotically, meiotic silencing by unpaired DNA, sex-induced silencing, cosuppression (also known as somatic quelling), and cotranscriptional RNA surveillance. Recent studies of the filamentous fungus Neurospora crassa have shown that the process of repeat recognition for RIP apparently involves interactions between coaligned double-stranded segments of chromosomal DNA. These studies have also shown that RIP can be mediated by the conserved pathway that establishes transcriptional (heterochromatic) silencing of repetitive DNA. In light of these new findings, RIP emerges as a specialized case of the general phenomenon of heterochromatic silencing of repetitive DNA.
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Rodenburg SYA, Terhem RB, Veloso J, Stassen JHM, van Kan JAL. Functional Analysis of Mating Type Genes and Transcriptome Analysis during Fruiting Body Development of Botrytis cinerea. mBio 2018; 9:e01939-17. [PMID: 29440571 PMCID: PMC5821092 DOI: 10.1128/mbio.01939-17] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/17/2018] [Indexed: 02/07/2023] Open
Abstract
Botrytis cinerea is a plant-pathogenic fungus producing apothecia as sexual fruiting bodies. To study the function of mating type (MAT) genes, single-gene deletion mutants were generated in both genes of the MAT1-1 locus and both genes of the MAT1-2 locus. Deletion mutants in two MAT genes were entirely sterile, while mutants in the other two MAT genes were able to develop stipes but never formed an apothecial disk. Little was known about the reprogramming of gene expression during apothecium development. We analyzed transcriptomes of sclerotia, three stages of apothecium development (primordia, stipes, and apothecial disks), and ascospores by RNA sequencing. Ten secondary metabolite gene clusters were upregulated at the onset of sexual development and downregulated in ascospores released from apothecia. Notably, more than 3,900 genes were differentially expressed in ascospores compared to mature apothecial disks. Among the genes that were upregulated in ascospores were numerous genes encoding virulence factors, which reveals that ascospores are transcriptionally primed for infection prior to their arrival on a host plant. Strikingly, the massive transcriptional changes at the initiation and completion of the sexual cycle often affected clusters of genes, rather than randomly dispersed genes. Thirty-five clusters of genes were jointly upregulated during the onset of sexual reproduction, while 99 clusters of genes (comprising >900 genes) were jointly downregulated in ascospores. These transcriptional changes coincided with changes in expression of genes encoding enzymes participating in chromatin organization, hinting at the occurrence of massive epigenetic regulation of gene expression during sexual reproduction.IMPORTANCE Fungal fruiting bodies are formed by sexual reproduction. We studied the development of fruiting bodies ("apothecia") of the ubiquitous plant-pathogenic ascomycete Botrytis cinerea The role of mating type genes in apothecium development was investigated by targeted mutation. Two genes are essential for the initiation of sexual development; mutants in these genes are sterile. Two other genes were not essential for development of stipes; however, they were essential for stipes to develop a disk and produce sexual ascospores. We examined gene expression profiles during apothecium development, as well as in ascospores sampled from apothecia. We provide the first study ever of the transcriptome of pure ascospores in a filamentous fungus. The expression of numerous genes involved in plant infection was induced in the ascospores, implying that ascospores are developmentally primed for infection before their release from apothecia.
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Affiliation(s)
- Sander Y A Rodenburg
- Laboratory of Phytopathology, Wageningen University, Wageningen, The Netherlands
- Wageningen University, Bioinformatics Group, Wageningen, The Netherlands
| | - Razak B Terhem
- Laboratory of Phytopathology, Wageningen University, Wageningen, The Netherlands
| | - Javier Veloso
- Laboratory of Phytopathology, Wageningen University, Wageningen, The Netherlands
- Department of Plant Physiology, Faculty of Sciences, University of A Coruña, A Coruña, Spain
| | - Joost H M Stassen
- Laboratory of Phytopathology, Wageningen University, Wageningen, The Netherlands
| | - Jan A L van Kan
- Laboratory of Phytopathology, Wageningen University, Wageningen, The Netherlands
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16
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Li WC, Chen CL, Wang TF. Repeat-induced point (RIP) mutation in the industrial workhorse fungus Trichoderma reesei. Appl Microbiol Biotechnol 2018; 102:1567-1574. [DOI: 10.1007/s00253-017-8731-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 12/18/2017] [Accepted: 12/20/2017] [Indexed: 02/01/2023]
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17
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DNA sequence homology induces cytosine-to-thymine mutation by a heterochromatin-related pathway in Neurospora. Nat Genet 2017; 49:887-894. [PMID: 28459455 PMCID: PMC5474309 DOI: 10.1038/ng.3857] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 03/31/2017] [Indexed: 12/16/2022]
Abstract
Eukaryotic genomes contain substantial amounts of repetitive DNA organized in the form of constitutive heterochromatin and associated with repressive epigenetic modifications, such as H3K9me3 and C5-cytosine methylation (5mC). In the fungus Neurospora crassa, H3K9me3 and 5mC are catalyzed, respectively, by a conserved SUV39 histone methyltransferase DIM-5 and a DNMT1-like cytosine methyltransferase DIM-2. Here we show that DIM-2 can also mediate Repeat-Induced Point mutation (RIP) of repetitive DNA in N. crassa. We further show that DIM-2-dependent RIP requires DIM-5, HP1, and other known heterochromatin factors, implying the role of a repeat-induced heterochromatin-related process. Our previous findings suggest that the mechanism of repeat recognition for RIP involves direct interactions between homologous double-stranded (ds) DNA segments. We thus now propose that, in somatic cells, homologous dsDNA/dsDNA interactions between a small number of repeat copies can nucleate a transient heterochromatic state, which, on longer repeat arrays, may lead to the formation of constitutive heterochromatin.
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18
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de Vries RP, Riley R, Wiebenga A, Aguilar-Osorio G, Amillis S, Uchima CA, Anderluh G, Asadollahi M, Askin M, Barry K, Battaglia E, Bayram Ö, Benocci T, Braus-Stromeyer SA, Caldana C, Cánovas D, Cerqueira GC, Chen F, Chen W, Choi C, Clum A, dos Santos RAC, Damásio ARDL, Diallinas G, Emri T, Fekete E, Flipphi M, Freyberg S, Gallo A, Gournas C, Habgood R, Hainaut M, Harispe ML, Henrissat B, Hildén KS, Hope R, Hossain A, Karabika E, Karaffa L, Karányi Z, Kraševec N, Kuo A, Kusch H, LaButti K, Lagendijk EL, Lapidus A, Levasseur A, Lindquist E, Lipzen A, Logrieco AF, MacCabe A, Mäkelä MR, Malavazi I, Melin P, Meyer V, Mielnichuk N, Miskei M, Molnár ÁP, Mulé G, Ngan CY, Orejas M, Orosz E, Ouedraogo JP, Overkamp KM, Park HS, Perrone G, Piumi F, Punt PJ, Ram AFJ, Ramón A, Rauscher S, Record E, Riaño-Pachón DM, Robert V, Röhrig J, Ruller R, Salamov A, Salih NS, Samson RA, Sándor E, Sanguinetti M, Schütze T, Sepčić K, Shelest E, Sherlock G, Sophianopoulou V, Squina FM, Sun H, Susca A, Todd RB, Tsang A, Unkles SE, van de Wiele N, van Rossen-Uffink D, Oliveira JVDC, Vesth TC, Visser J, Yu JH, Zhou M, Andersen MR, Archer DB, Baker SE, Benoit I, Brakhage AA, Braus GH, Fischer R, Frisvad JC, Goldman GH, Houbraken J, Oakley B, Pócsi I, Scazzocchio C, Seiboth B, vanKuyk PA, Wortman J, Dyer PS, Grigoriev IV. Comparative genomics reveals high biological diversity and specific adaptations in the industrially and medically important fungal genus Aspergillus. Genome Biol 2017; 18:28. [PMID: 28196534 PMCID: PMC5307856 DOI: 10.1186/s13059-017-1151-0] [Citation(s) in RCA: 316] [Impact Index Per Article: 45.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 01/10/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The fungal genus Aspergillus is of critical importance to humankind. Species include those with industrial applications, important pathogens of humans, animals and crops, a source of potent carcinogenic contaminants of food, and an important genetic model. The genome sequences of eight aspergilli have already been explored to investigate aspects of fungal biology, raising questions about evolution and specialization within this genus. RESULTS We have generated genome sequences for ten novel, highly diverse Aspergillus species and compared these in detail to sister and more distant genera. Comparative studies of key aspects of fungal biology, including primary and secondary metabolism, stress response, biomass degradation, and signal transduction, revealed both conservation and diversity among the species. Observed genomic differences were validated with experimental studies. This revealed several highlights, such as the potential for sex in asexual species, organic acid production genes being a key feature of black aspergilli, alternative approaches for degrading plant biomass, and indications for the genetic basis of stress response. A genome-wide phylogenetic analysis demonstrated in detail the relationship of the newly genome sequenced species with other aspergilli. CONCLUSIONS Many aspects of biological differences between fungal species cannot be explained by current knowledge obtained from genome sequences. The comparative genomics and experimental study, presented here, allows for the first time a genus-wide view of the biological diversity of the aspergilli and in many, but not all, cases linked genome differences to phenotype. Insights gained could be exploited for biotechnological and medical applications of fungi.
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Affiliation(s)
- Ronald P. de Vries
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Robert Riley
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Ad Wiebenga
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Guillermo Aguilar-Osorio
- Department of Food Science and Biotechnology, Faculty of Chemistry, National University of Mexico, Ciudad Universitaria, D.F. C.P. 04510 Mexico
| | - Sotiris Amillis
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15781 Athens, Greece
| | - Cristiane Akemi Uchima
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
- Present address: VTT Brasil, Alameda Inajá, 123, CEP 06460-055 Barueri, São Paulo Brazil
| | - Gregor Anderluh
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Mojtaba Asadollahi
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Marion Askin
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Present address: CSIRO Publishing, Unipark, Building 1 Level 1, 195 Wellington Road, Clayton, VIC 3168 Australia
| | - Kerrie Barry
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Evy Battaglia
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Özgür Bayram
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
- Department of Biology, Maynooth University, Maynooth, Co. Kildare Ireland
| | - Tiziano Benocci
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Susanna A. Braus-Stromeyer
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Camila Caldana
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
- Max Planck Partner Group, Brazilian Bioethanol Science and Technology Laboratory, CEP 13083-100 Campinas, Sao Paulo Brazil
| | - David Cánovas
- Department of Genetics, Faculty of Biology, University of Seville, Avda de Reina Mercedes 6, 41012 Sevilla, Spain
- Fungal Genetics and Genomics Unit, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU) Vienna, Vienna, Austria
| | | | - Fusheng Chen
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Wanping Chen
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Cindy Choi
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Alicia Clum
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Renato Augusto Corrêa dos Santos
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - André Ricardo de Lima Damásio
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, CEP 13083-862 Campinas, SP Brazil
| | - George Diallinas
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15781 Athens, Greece
| | - Tamás Emri
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Erzsébet Fekete
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Michel Flipphi
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Susanne Freyberg
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Antonia Gallo
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), via Provinciale Lecce-Monteroni, 73100 Lecce, Italy
| | - Christos Gournas
- Institute of Biosciences and Applications, Microbial Molecular Genetics Laboratory, National Center for Scientific Research, Demokritos (NCSRD), Athens, Greece
- Present address: Université Libre de Bruxelles Institute of Molecular Biology and Medicine (IBMM), Brussels, Belgium
| | - Rob Habgood
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | | | - María Laura Harispe
- Institut Pasteur de Montevideo, Unidad Mixta INIA-IPMont, Mataojo 2020, CP11400 Montevideo, Uruguay
- Present address: Instituto de Profesores Artigas, Consejo de Formación en Educación, ANEP, CP 11800, Av. del Libertador 2025, Montevideo, Uruguay
| | - Bernard Henrissat
- CNRS, Aix-Marseille Université, Marseille, France
- INRA, USC 1408 AFMB, 13288 Marseille, France
- Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Kristiina S. Hildén
- Department of Food and Environmental Sciences, University of Helsinki, Viikinkaari 9, Helsinki, Finland
| | - Ryan Hope
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Abeer Hossain
- Dutch DNA Biotech BV, Utrechtseweg 48, 3703AJ Zeist, The Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Eugenia Karabika
- School of Biology, University of St Andrews, St Andrews, Fife KY16 9TH UK
- Present Address: Department of Chemistry, University of Ioannina, Ioannina, 45110 Greece
| | - Levente Karaffa
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Zsolt Karányi
- Department of Medicine, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4032 Debrecen, Hungary
| | - Nada Kraševec
- Laboratory for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Alan Kuo
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Harald Kusch
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
- Department of Medical Informatics, University Medical Centre, Robert-Koch-Str.40, 37075 Göttingen, Germany
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, Göttingen, 37073 Germany
| | - Kurt LaButti
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Ellen L. Lagendijk
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Alla Lapidus
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
- Present address: Center for Algorithmic Biotechnology, St.Petersburg State University, St. Petersburg, Russia
| | - Anthony Levasseur
- INRA, Aix-Marseille Univ, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
- Present address: Aix-Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE), UM63, CNRS 7278, IRD 198, INSERM U1095, IHU Méditerranée Infection, Pôle des Maladies Infectieuses, Assistance Publique-Hôpitaux de Marseille, Faculté de Médecine, 27 Bd Jean Moulin, 13005 Marseille, France
| | - Erika Lindquist
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Anna Lipzen
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Antonio F. Logrieco
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Andrew MacCabe
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Miia R. Mäkelä
- Department of Food and Environmental Sciences, University of Helsinki, Viikinkaari 9, Helsinki, Finland
| | - Iran Malavazi
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo Brazil
| | - Petter Melin
- Uppsala BioCenter, Department of Microbiology, Swedish University of Agricultural Sciences, P.O. Box 7025, 750 07 Uppsala, Sweden
- Present address: Swedish Chemicals Agency, Box 2, 172 13 Sundbyberg, Sweden
| | - Vera Meyer
- Institute of Biotechnology, Department Applied and Molecular Microbiology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Natalia Mielnichuk
- Department of Genetics, Faculty of Biology, University of Seville, Avda de Reina Mercedes 6, 41012 Sevilla, Spain
- Present address: Instituto de Ciencia y Tecnología Dr. César Milstein, Fundación Pablo Cassará, CONICET, Saladillo 2468 C1440FFX, Ciudad de Buenos Aires, Argentina
| | - Márton Miskei
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
- MTA-DE Momentum, Laboratory of Protein Dynamics, Department of Biochemistry and Molecular Biology, University of Debrecen, Nagyerdei krt.98., 4032 Debrecen, Hungary
| | - Ákos P. Molnár
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - Giuseppina Mulé
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Chew Yee Ngan
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Margarita Orejas
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Erzsébet Orosz
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Jean Paul Ouedraogo
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Present address: Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke Street West, Montreal, QC H4B 1R6 Canada
| | - Karin M. Overkamp
- Dutch DNA Biotech BV, Utrechtseweg 48, 3703AJ Zeist, The Netherlands
| | - Hee-Soo Park
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, 702-701 Republic of Korea
| | - Giancarlo Perrone
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Francois Piumi
- INRA, Aix-Marseille Univ, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
- Present address: INRA UMR1198 Biologie du Développement et de la Reproduction - Domaine de Vilvert, Jouy en Josas, 78352 Cedex France
| | - Peter J. Punt
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Dutch DNA Biotech BV, Utrechtseweg 48, 3703AJ Zeist, The Netherlands
| | - Arthur F. J. Ram
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Ana Ramón
- Sección Bioquímica, Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Stefan Rauscher
- Department of Microbiology, Karlsruhe Institute of Technology, Institute for Applied Biosciences, Hertzstrasse 16,, 76187 Karlsruhe, Germany
| | - Eric Record
- INRA, Aix-Marseille Univ, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
| | - Diego Mauricio Riaño-Pachón
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - Vincent Robert
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Julian Röhrig
- Department of Microbiology, Karlsruhe Institute of Technology, Institute for Applied Biosciences, Hertzstrasse 16,, 76187 Karlsruhe, Germany
| | - Roberto Ruller
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - Asaf Salamov
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Nadhira S. Salih
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
- Department of Biology, School of Science, University of Sulaimani, Al Sulaymaneyah, Iraq
| | - Rob A. Samson
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Erzsébet Sándor
- Institute of Food Science, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, 4032 Debrecen, Hungary
| | - Manuel Sanguinetti
- Sección Bioquímica, Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Tabea Schütze
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Present address: Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
| | - Ekaterina Shelest
- Systems Biology/Bioinformatics group, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Gavin Sherlock
- Department of Genetics, Stanford University, Stanford, CA 94305-5120 USA
| | - Vicky Sophianopoulou
- Institute of Biosciences and Applications, Microbial Molecular Genetics Laboratory, National Center for Scientific Research, Demokritos (NCSRD), Athens, Greece
| | - Fabio M. Squina
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - Hui Sun
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Antonia Susca
- Institute of Sciences of Food Production (ISPA), National Research Council (CNR), Via Amendola 122/O, 70126 Bari, Italy
| | - Richard B. Todd
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506 USA
| | - Adrian Tsang
- Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke Street West, Montreal, QC H4B 1R6 Canada
| | - Shiela E. Unkles
- School of Biology, University of St Andrews, St Andrews, Fife KY16 9TH UK
| | - Nathalie van de Wiele
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Diana van Rossen-Uffink
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
- Present address: BaseClear B.V., Einsteinweg 5, 2333 CC Leiden, The Netherlands
| | - Juliana Velasco de Castro Oliveira
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192 CEP 13083-970, Campinas, São Paulo Brasil
| | - Tammi C. Vesth
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 223, 2800 Kongens Lyngby, Denmark
| | - Jaap Visser
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Jae-Hyuk Yu
- Departments of Bacteriology and Genetics, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706 USA
| | - Miaomiao Zhou
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Mikael R. Andersen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 223, 2800 Kongens Lyngby, Denmark
| | - David B. Archer
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Scott E. Baker
- Fungal Biotechnology Team, Pacific Northwest National Laboratory, Richland, Washington, 99352 USA
| | - Isabelle Benoit
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Present address: Centre of Functional and Structure Genomics Biology Department Concordia University, 7141 Sherbrooke St. W., Montreal, QC H4B 1R6 Canada
| | - Axel A. Brakhage
- Department of Molecular and Applied Microbiology, Leibniz-Institute for Natural Product Research and Infection Biology - Hans Knoell Institute (HKI) and Institute for Microbiology, Friedrich Schiller University Jena, Beutenbergstr. 11a, 07745 Jena, Germany
| | - Gerhard H. Braus
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Reinhard Fischer
- Department of Microbiology, Karlsruhe Institute of Technology, Institute for Applied Biosciences, Hertzstrasse 16,, 76187 Karlsruhe, Germany
| | - Jens C. Frisvad
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 223, 2800 Kongens Lyngby, Denmark
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903 Ribeirão Preto, São Paulo Brazil
| | - Jos Houbraken
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Berl Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045 USA
| | - István Pócsi
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Claudio Scazzocchio
- Department of Microbiology, Imperial College, London, SW7 2AZ UK
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, University Paris‐Sud, Université Paris‐Saclay, 91198 Gif‐sur‐Yvette cedex, France
| | - Bernhard Seiboth
- Research Division Biochemical Technology, Institute of Chemical Engineering, TU Wien, Gumpendorferstraße 1a, 1060 Vienna, Austria
| | - Patricia A. vanKuyk
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Jennifer Wortman
- Broad Institute, 415 Main St, Cambridge, MA 02142 USA
- Present address: Seres Therapeutics, 200 Sidney St, Cambridge, MA 02139 USA
| | - Paul S. Dyer
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Igor V. Grigoriev
- US Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
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19
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Huang R, Ding Q, Xiang Y, Gu T, Li Y. Comparative Analysis of DNA Methyltransferase Gene Family in Fungi: A Focus on Basidiomycota. FRONTIERS IN PLANT SCIENCE 2016; 7:1556. [PMID: 27818666 PMCID: PMC5073141 DOI: 10.3389/fpls.2016.01556] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 10/03/2016] [Indexed: 06/06/2023]
Abstract
DNA methylation plays a crucial role in the regulation of gene expression in eukaryotes. Mushrooms belonging to the phylum Basidiomycota are highly valued for both nutritional and pharmaceutical uses. A growing number of studies have demonstrated the significance of DNA methylation in the development of plants and animals. However, our understanding of DNA methylation in mushrooms is limited. In this study, we identified and conducted comprehensive analyses on DNA methyltransferases (DNMtases) in representative species from Basidiomycota and Ascomycota, and obtained new insights into their classification and characterization in fungi. Our results revealed that DNMtases in basidiomycetes can be divided into two classes, the Dnmt1 class and the newly defined Rad8 class. We also demonstrated that the fusion event between the characteristic domains of the DNMtases family and Snf2 family in the Rad8 class is fungi-specific, possibly indicating a functional novelty of Rad8 DNMtases in fungi. Additionally, expression profiles of DNMtases in the edible mushroom Pleurotus ostreatus revealed diverse expression patterns in various organs and developmental stages. For example, DNMtase genes displayed higher expression levels in dikaryons than in monokaryons. Consistent with the expression profiles, we found that dikaryons are more susceptible to the DNA methyltransferase inhibitor 5-azacytidine. Taken together, our findings pinpoint an important role of DNA methylation during the growth of mushrooms and provide a foundation for understanding of DNMtases in basidiomycetes.
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Affiliation(s)
- Ruirui Huang
- State Key Laboratory of Plant Genetics and Germplasm Enhancement and College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Qiangqiang Ding
- State Key Laboratory of Plant Genetics and Germplasm Enhancement and College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Yanan Xiang
- Laboratory of Plant Hormone, College of Life Sciences, Nanjing Agricultural UniversityNanjing, China
| | - Tingting Gu
- State Key Laboratory of Plant Genetics and Germplasm Enhancement and College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Yi Li
- State Key Laboratory of Plant Genetics and Germplasm Enhancement and College of Horticulture, Nanjing Agricultural UniversityNanjing, China
- Department of Plant Science and Landscape Architecture, University of ConnecticutStorrs, CT, USA
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20
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Gladyshev E, Kleckner N. Recombination-independent recognition of DNA homology for repeat-induced point mutation. Curr Genet 2016; 63:389-400. [PMID: 27628707 DOI: 10.1007/s00294-016-0649-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 09/04/2016] [Accepted: 09/06/2016] [Indexed: 12/31/2022]
Abstract
Numerous cytogenetic observations have shown that homologous chromosomes (or individual chromosomal loci) can engage in specific pairing interactions in the apparent absence of DNA breakage and recombination, suggesting that canonical recombination-mediated mechanisms may not be the only option for sensing DNA/DNA homology. One proposed mechanism for such recombination-independent homology recognition involves direct contacts between intact double-stranded DNA molecules. The strongest in vivo evidence for the existence of such a mechanism is provided by the phenomena of homology-directed DNA modifications in fungi, known as repeat-induced point mutation (RIP, discovered in Neurospora crassa) and methylation-induced premeiotically (MIP, discovered in Ascobolus immersus). In principle, Neurospora RIP can detect the presence of gene-sized DNA duplications irrespectively of their origin, underlying nucleotide sequence, coding capacity or relative, as well as absolute positions in the genome. Once detected, both sequence copies are altered by numerous cytosine-to-thymine (C-to-T) mutations that extend specifically over the duplicated region. We have recently shown that Neurospora RIP does not require MEI-3, the only RecA/Rad51 protein in this organism, consistent with a recombination-independent mechanism. Using an ultra-sensitive assay for RIP mutation, we have defined additional features of this process. We have shown that RIP can detect short islands of homology of only three base-pairs as long as many such islands are arrayed with a periodicity of 11 or 12 base-pairs along a pair of DNA molecules. While the presence of perfect homology is advantageous, it is not required: chromosomal segments with overall sequence identity of only 35-36 % can still be recognized by RIP. Importantly, in order for this process to work efficiently, participating DNA molecules must be able to co-align along their lengths. Based on these findings, we have proposed a model, in which sequence homology is detected by direct interactions between slightly-extended double-stranded DNAs. As a next step, it will be important to determine if the uncovered principles also apply to other processes that involve recombination-independent interactions between homologous chromosomal loci in vivo as well as to protein-free DNA/DNA interactions that were recently observed under biologically relevant conditions in vitro.
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Affiliation(s)
- Eugene Gladyshev
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Room NW140, Cambridge, MA, 02138, USA.
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Room NW140, Cambridge, MA, 02138, USA.
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21
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Gladyshev E, Kleckner N. Recombination-Independent Recognition of DNA Homology for Repeat-Induced Point Mutation (RIP) Is Modulated by the Underlying Nucleotide Sequence. PLoS Genet 2016; 12:e1006015. [PMID: 27148882 PMCID: PMC4858203 DOI: 10.1371/journal.pgen.1006015] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 04/06/2016] [Indexed: 11/18/2022] Open
Abstract
Haploid germline nuclei of many filamentous fungi have the capacity to detect homologous nucleotide sequences present on the same or different chromosomes. Once recognized, such sequences can undergo cytosine methylation or cytosine-to-thymine mutation specifically over the extent of shared homology. In Neurospora crassa this process is known as Repeat-Induced Point mutation (RIP). Previously, we showed that RIP did not require MEI-3, the only RecA homolog in Neurospora, and that it could detect homologous trinucleotides interspersed with a matching periodicity of 11 or 12 base-pairs along participating chromosomal segments. This pattern was consistent with a mechanism of homology recognition that involved direct interactions between co-aligned double-stranded (ds) DNA molecules, where sequence-specific dsDNA/dsDNA contacts could be established using no more than one triplet per turn. In the present study we have further explored the DNA sequence requirements for RIP. In our previous work, interspersed homologies were always examined in the context of a relatively long adjoining region of perfect homology. Using a new repeat system lacking this strong interaction, we now show that interspersed homologies with overall sequence identity of only 36% can be efficiently detected by RIP in the absence of any perfect homology. Furthermore, in this new system, where the total amount of homology is near the critical threshold required for RIP, the nucleotide composition of participating DNA molecules is identified as an important factor. Our results specifically pinpoint the triplet 5'-GAC-3' as a particularly efficient unit of homology recognition. Finally, we present experimental evidence that the process of homology sensing can be uncoupled from the downstream mutation. Taken together, our results advance the notion that sequence information can be compared directly between double-stranded DNA molecules during RIP and, potentially, in other processes where homologous pairing of intact DNA molecules is observed.
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Affiliation(s)
- Eugene Gladyshev
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
- * E-mail: (EG); (NK)
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
- * E-mail: (EG); (NK)
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22
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Ashapkin VV, Kutueva LI, Vanyushin BF. Dnmt2 is the most evolutionary conserved and enigmatic cytosine DNA methyltransferase in eukaryotes. RUSS J GENET+ 2016. [DOI: 10.1134/s1022795416030029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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23
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Aghcheh RK, Kubicek CP. Epigenetics as an emerging tool for improvement of fungal strains used in biotechnology. Appl Microbiol Biotechnol 2015; 99:6167-81. [PMID: 26115753 DOI: 10.1007/s00253-015-6763-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 06/07/2015] [Accepted: 06/10/2015] [Indexed: 10/23/2022]
Abstract
Filamentous fungi are today a major source of industrial biotechnology for the production of primary and secondary metabolites, as well as enzymes and recombinant proteins. All of them have undergone extensive improvement strain programs, initially by classical mutagenesis and later on by genetic manipulation. Thereby, strategies to overcome rate-limiting or yield-reducing reactions included manipulating the expression of individual genes, their regulatory genes, and also their function. Yet, research of the last decade clearly showed that cells can also undergo heritable changes in gene expression that do not involve changes in the underlying DNA sequences (=epigenetics). This involves three levels of regulation: (i) DNA methylation, (ii) chromatin remodeling by histone modification, and (iii) RNA interference. The demonstration of the occurrence of these processes in fungal model organisms such as Aspergillus nidulans and Neurospora crassa has stimulated its recent investigation as a tool for strain improvement in industrially used fungi. This review describes the progress that has thereby been obtained.
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Affiliation(s)
- Razieh Karimi Aghcheh
- Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9/166-5, 1060, Vienna, Austria,
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24
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Amselem J, Lebrun MH, Quesneville H. Whole genome comparative analysis of transposable elements provides new insight into mechanisms of their inactivation in fungal genomes. BMC Genomics 2015. [PMID: 25766680 DOI: 10.1186/s12864-015-1347-1341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
BACKGROUND Transposable Elements (TEs) are key components that shape the organization and evolution of genomes. Fungi have developed defense mechanisms against TE invasion such as RIP (Repeat-Induced Point mutation), MIP (Methylation Induced Premeiotically) and Quelling (RNA interference). RIP inactivates repeated sequences by promoting Cytosine to Thymine mutations, whereas MIP only methylates TEs at C residues. Both mechanisms require specific cytosine DNA Methyltransferases (RID1/Masc1) of the Dnmt1 superfamily. RESULTS We annotated TE sequences from 10 fungal genomes with different TE content (1-70%). We then used these TE sequences to carry out a genome-wide analysis of C to T mutations biases. Genomes from either Ascomycota or Basidiomycota that were massively invaded by TEs (Blumeria, Melampsora, Puccinia) were characterized by a low frequency of C to T mutation bias (10-20%), whereas other genomes displayed intermediate to high frequencies (25-75%). We identified several dinucleotide signatures at these C to T mutation sites (CpA, CpT, and CpG). Phylogenomic analysis of fungal Dnmt1 MTases revealed a previously unreported association between these dinucleotide signatures and the presence/absence of sub-classes of Dnmt1. CONCLUSIONS We identified fungal genomes containing large numbers of TEs with many C to T mutations associated with species-specific dinucleotide signatures. This bias suggests that a basic defense mechanism against TE invasion similar to RIP is widespread in fungi, although the efficiency and specificity of this mechanism differs between species. Our analysis revealed that dinucleotide signatures are associated with the presence/absence of specific Dnmt1 subfamilies. In particular, an RID1-dependent RIP mechanism was found only in Ascomycota.
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Affiliation(s)
- Joëlle Amselem
- INRA, UR1164 URGI Research Unit in Genomics-Info, F-78026, Versailles, France.
- INRA, UR1290 BIOGER, Biologie et gestion des risques en agriculture, Campus AgroParisTech, F-78850, Thiverval-Grignon, France.
| | - Marc-Henri Lebrun
- INRA, UR1290 BIOGER, Biologie et gestion des risques en agriculture, Campus AgroParisTech, F-78850, Thiverval-Grignon, France.
| | - Hadi Quesneville
- INRA, UR1164 URGI Research Unit in Genomics-Info, F-78026, Versailles, France.
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25
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Amselem J, Lebrun MH, Quesneville H. Whole genome comparative analysis of transposable elements provides new insight into mechanisms of their inactivation in fungal genomes. BMC Genomics 2015; 16:141. [PMID: 25766680 PMCID: PMC4352252 DOI: 10.1186/s12864-015-1347-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 02/16/2015] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Transposable Elements (TEs) are key components that shape the organization and evolution of genomes. Fungi have developed defense mechanisms against TE invasion such as RIP (Repeat-Induced Point mutation), MIP (Methylation Induced Premeiotically) and Quelling (RNA interference). RIP inactivates repeated sequences by promoting Cytosine to Thymine mutations, whereas MIP only methylates TEs at C residues. Both mechanisms require specific cytosine DNA Methyltransferases (RID1/Masc1) of the Dnmt1 superfamily. RESULTS We annotated TE sequences from 10 fungal genomes with different TE content (1-70%). We then used these TE sequences to carry out a genome-wide analysis of C to T mutations biases. Genomes from either Ascomycota or Basidiomycota that were massively invaded by TEs (Blumeria, Melampsora, Puccinia) were characterized by a low frequency of C to T mutation bias (10-20%), whereas other genomes displayed intermediate to high frequencies (25-75%). We identified several dinucleotide signatures at these C to T mutation sites (CpA, CpT, and CpG). Phylogenomic analysis of fungal Dnmt1 MTases revealed a previously unreported association between these dinucleotide signatures and the presence/absence of sub-classes of Dnmt1. CONCLUSIONS We identified fungal genomes containing large numbers of TEs with many C to T mutations associated with species-specific dinucleotide signatures. This bias suggests that a basic defense mechanism against TE invasion similar to RIP is widespread in fungi, although the efficiency and specificity of this mechanism differs between species. Our analysis revealed that dinucleotide signatures are associated with the presence/absence of specific Dnmt1 subfamilies. In particular, an RID1-dependent RIP mechanism was found only in Ascomycota.
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Affiliation(s)
- Joëlle Amselem
- INRA, UR1164 URGI Research Unit in Genomics-Info, F-78026, Versailles, France. .,INRA, UR1290 BIOGER, Biologie et gestion des risques en agriculture, Campus AgroParisTech, F-78850, Thiverval-Grignon, France.
| | - Marc-Henri Lebrun
- INRA, UR1290 BIOGER, Biologie et gestion des risques en agriculture, Campus AgroParisTech, F-78850, Thiverval-Grignon, France.
| | - Hadi Quesneville
- INRA, UR1164 URGI Research Unit in Genomics-Info, F-78026, Versailles, France.
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Jeon J, Choi J, Lee GW, Park SY, Huh A, Dean RA, Lee YH. Genome-wide profiling of DNA methylation provides insights into epigenetic regulation of fungal development in a plant pathogenic fungus, Magnaporthe oryzae. Sci Rep 2015; 5:8567. [PMID: 25708804 PMCID: PMC4338423 DOI: 10.1038/srep08567] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 01/23/2015] [Indexed: 12/11/2022] Open
Abstract
DNA methylation is an important epigenetic modification that regulates development of plants and mammals. To investigate the roles of DNA methylation in fungal development, we profiled genome-wide methylation patterns at single-nucleotide resolution during vegetative growth, asexual reproduction, and infection-related morphogenesis in a model plant pathogenic fungus, Magnaporthe oryzae. We found that DNA methylation occurs in and around genes as well as transposable elements and undergoes global reprogramming during fungal development. Such reprogramming of DNA methylation suggests that it may have acquired new roles other than controlling the proliferation of TEs. Genetic analysis of DNA methyltransferase deletion mutants also indicated that proper reprogramming in methylomes is required for asexual reproduction in the fungus. Furthermore, RNA-seq analysis showed that DNA methylation is associated with transcriptional silencing of transposable elements and transcript abundance of genes in context-dependent manner, reinforcing the role of DNA methylation as a genome defense mechanism. This comprehensive approach suggests that DNA methylation in fungi can be a dynamic epigenetic entity contributing to fungal development and genome defense. Furthermore, our DNA methylomes provide a foundation for future studies exploring this key epigenetic modification in fungal development and pathogenesis.
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Affiliation(s)
- Junhyun Jeon
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
| | - Jaeyoung Choi
- 1] Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea [2] Fungal Bioinformatics Laboratory, Seoul National University, Seoul 151-921, Korea
| | - Gir-Won Lee
- Department of Bioinformatics and Life Science, Soongsil University, Seoul 156-743, Korea
| | - Sook-Young Park
- Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Korea
| | - Aram Huh
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
| | - Ralph A Dean
- Functional Genomics, North Carolina State University, Raleigh, NC 27607, United States of America
| | - Yong-Hwan Lee
- 1] Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea [2] Fungal Bioinformatics Laboratory, Seoul National University, Seoul 151-921, Korea [3] Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Korea [4] Center for Fungal Genetic Resources, Seoul National University, Seoul 151-921, Korea
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27
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Gladyshev E, Kleckner N. Direct recognition of homology between double helices of DNA in Neurospora crassa. Nat Commun 2014; 5:3509. [PMID: 24699390 PMCID: PMC4000310 DOI: 10.1038/ncomms4509] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 02/25/2014] [Indexed: 12/11/2022] Open
Abstract
Chromosomal regions of identical or nearly identical DNA sequence can preferentially associate with one another in the apparent absence of DNA breakage. Molecular mechanism(s) underlying such homology-dependent pairing phenomena remain(s) unknown. Using Neurospora crassa repeat-induced point mutation (RIP) as a model system, we show that a pair of DNA segments can be recognized as homologous if they share triplets of base pairs arrayed with the matching periodicity of 11 or 12 base pairs. This pattern suggests direct interactions between slightly underwound co-aligned DNA duplexes engaging once per turn and over many consecutive turns. The process occurs in the absence of MEI3, the only RAD51/DMC1 protein in N. crassa, demonstrating independence from the canonical homology recognition pathway. A new perspective is thus provided for further analysis of the breakage-independent recognition of homology that underlies RIP and, potentially, other processes where sequence-specific pairing of intact chromosomes is involved.
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Affiliation(s)
- Eugene Gladyshev
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Room NW140, Cambridge, Massachusetts 02138, USA
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Room NW140, Cambridge, Massachusetts 02138, USA
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28
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Abstract
The long terminal repeat retrotransposon, Magnaporthe gypsy-like element (MAGGY), has been shown to be targeted for cytosine methylation in a subset of Magnaporthe oryzae field isolates. Analysis of the F1 progeny from a genetic cross between methylation-proficient (Br48) and methylation-deficient (GFSI1-7-2) isolates revealed that methylation of the MAGGY element was governed by a single dominant gene. Positional cloning followed by gene disruption and complementation experiments revealed that the responsible gene was the DNA methyltransferase, MoDMT1, an ortholog of Neurospora crassa Dim-2. A survey of MAGGY methylation in 60 Magnaporthe field isolates revealed that 42 isolates from rice, common millet, wheat, finger millet, and buffelgrass were methylation proficient while 18 isolates from foxtail millet, green bristlegrass, Japanese panicgrass, torpedo grass, Guinea grass, and crabgrass were methylation deficient. Phenotypic analyses showed that MoDMT1 plays no major role in development and pathogenicity of the fungus. Quantitative polymerase chain reaction analysis showed that the average copy number of genomic MAGGY elements was not significantly different between methylation-deficient and -proficient field isolates even though the levels of MAGGY transcript were generally higher in the former group. MoDMT1 gene sequences in the methylation-deficient isolates suggested that at least three independent mutations were responsible for the loss of MoDMT1 function. Overall, our data suggest that MoDMT1 is not essential for the natural life cycle of the fungus and raise the possibility that the genus Magnaporthe may be losing the mechanism of DNA methylation on the evolutionary time scale.
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29
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Mao X, Wei M, Zhu C, Lu J, Gao J, Simon AJ, Shi J, Huang Q, Fan C. Real time in vitro regulation of DNA methylation using a 5-fluorouracil conjugated DNA-based stimuli-responsive platform. ACS APPLIED MATERIALS & INTERFACES 2013; 5:2604-2609. [PMID: 23480369 DOI: 10.1021/am3033052] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
DNA methylation, catalyzed by methylases, plays a critical role in many biological processes, and many methylases have been regarded as promising targets for antimicrobial drugs. In this work, we report a stimulus responsive, self-regulating anticancer drug release platform, comprising a multifunctional DNA that upon methylation by methyltransferase (MTase) releases 5-fluorouracil (5-Fu) and in turn inhibits subsequent expression of MTase. The multifunctional DNA with anticancer drug are first methylated by DNA adenine methylation (DAM) methyltransferase (MTase) and then cut by the methylation-sensitive restriction endonuclease Dpn I. Removal of duplex from the functional DNA by the methylation/cleavage process will release the anticancer drug, resulting in inhibition of the activity of DAM in turn. Consequently, the enzyme activity of DAM MTase can be self-regulated. Furthermore, we found that the inhibition efficiency of 5-Fu significantly increase as it is functionalized with DNA.
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Affiliation(s)
- Xiuhai Mao
- Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China
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Abstract
We report a novel sexual-cycle-specific gene-silencing system in the genetic model Aspergillus nidulans. Duplication of the mating type matA(HMG) gene in this haploid organism triggers Mat-induced silencing (MatIS) of both endogenous and transgenic matA genes, eliminates function of the encoded SRY structural ortholog, and results in formation of barren fruiting bodies. MatIS is spatiotemporally restricted to the prezygotic stage of the sexual cycle and does not interfere with vegetative growth, asexual reproduction, differentiation of early sexual tissues, or fruiting body development. MatIS is reversible upon deletion of the matA transgene. In contrast to other sex-specific silencing phenomena, MatIS silencing has nearly 100% efficiency and appears to be independent of homologous duplicated DNA segments. Remarkably, transgene-derived matA RNA might be sufficient to induce MatIS. A unique feature of MatIS is that RNA-mediated silencing is RNA interference/Argonaute-independent and is restricted to the nucleus having the duplicated gene. The silencing phenomenon is recessive and does not spread between nuclei within the common cytoplasm of a multinucleate heterokaryon. Gene silencing induced by matA gene duplication emerges as a specific feature associated with matA(HMG) regulation during sexual development.
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Henk DA, Shahar-Golan R, Devi KR, Boyce KJ, Zhan N, Fedorova ND, Nierman WC, Hsueh PR, Yuen KY, Sieu TPM, Kinh NV, Wertheim H, Baker SG, Day JN, Vanittanakom N, Bignell EM, Andrianopoulos A, Fisher MC. Clonality despite sex: the evolution of host-associated sexual neighborhoods in the pathogenic fungus Penicillium marneffei. PLoS Pathog 2012; 8:e1002851. [PMID: 23055919 PMCID: PMC3464222 DOI: 10.1371/journal.ppat.1002851] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 06/25/2012] [Indexed: 12/04/2022] Open
Abstract
Molecular genetic approaches typically detect recombination in microbes regardless of assumed asexuality. However, genetic data have shown the AIDS-associated pathogen Penicillium marneffei to have extensive spatial genetic structure at local and regional scales, and although there has been some genetic evidence that a sexual cycle is possible, this haploid fungus is thought to be genetically, as well as morphologically, asexual in nature because of its highly clonal population structure. Here we use comparative genomics, experimental mixed-genotype infections, and population genetic data to elucidate the role of recombination in natural populations of P. marneffei. Genome wide comparisons reveal that all the genes required for meiosis are present in P. marneffei, mating type genes are arranged in a similar manner to that found in other heterothallic fungi, and there is evidence of a putatively meiosis-specific mutational process. Experiments suggest that recombination between isolates of compatible mating types may occur during mammal infection. Population genetic data from 34 isolates from bamboo rats in India, Thailand and Vietnam, and 273 isolates from humans in China, India, Thailand, and Vietnam show that recombination is most likely to occur across spatially and genetically limited distances in natural populations resulting in highly clonal population structure yet sexually reproducing populations. Predicted distributions of three different spatial genetic clusters within P. marneffei overlap with three different bamboo rat host distributions suggesting that recombination within hosts may act to maintain population barriers within P. marneffei.
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Affiliation(s)
- Daniel A Henk
- Department of Infectious Disease Epidemiology, Imperial College, Norfolk Place, London, United Kingdom.
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Clutterbuck AJ. Genomic evidence of repeat-induced point mutation (RIP) in filamentous ascomycetes. Fungal Genet Biol 2011; 48:306-26. [PMID: 20854921 DOI: 10.1016/j.fgb.2010.09.002] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 09/14/2010] [Accepted: 09/14/2010] [Indexed: 11/18/2022]
Affiliation(s)
- A John Clutterbuck
- School of Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK.
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Natural history of eukaryotic DNA methylation systems. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 101:25-104. [PMID: 21507349 DOI: 10.1016/b978-0-12-387685-0.00002-0] [Citation(s) in RCA: 151] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Methylation of cytosines and adenines in DNA is a widespread epigenetic mark in both prokaryotes and eukaryotes. In eukaryotes, it has a profound influence on chromatin structure and dynamics. Recent advances in genomics and biochemistry have considerably elucidated the functions and provenance of these DNA modifications. DNA methylases appear to have emerged first in bacterial restriction-modification (R-M) systems from ancient RNA-modifying enzymes, in transitions that involved acquisition of novel catalytic residues and DNA-recognition features. DNA adenine methylases appear to have been acquired by ciliates, heterolobosean amoeboflagellates, and certain chlorophyte algae. Six distinct clades of cytosine methylases, including the DNMT1, DNMT2, and DNMT3 clades, were acquired by eukaryotes through independent lateral transfer of their precursors from bacteria or bacteriophages. In addition to these, multiple adenine and cytosine methylases were acquired by several families of eukaryotic transposons. In eukaryotes, the DNA-methylase module was often combined with distinct modified and unmodified peptide recognition domains and other modules mediating specialized interactions, for example, the RFD module of DNMT1 which contains a permuted Sm domain linked to a helix-turn-helix domain. In eukaryotes, the evolution of DNA methylases appears to have proceeded in parallel to the elaboration of histone-modifying enzymes and the RNAi system, with functions related to counter-viral and counter-transposon defense, and regulation of DNA repair and differential gene expression being their primary ancestral functions. Diverse DNA demethylation systems that utilize base-excision repair via DNA glycosylases and cytosine deaminases appear to have emerged in multiple eukaryotic lineages. Comparative genomics suggests that the link between cytosine methylation and DNA glycosylases probably emerged first in a novel R-M system in bacteria. Recent studies suggest that the 5mC is not a terminal DNA modification, with enzymes of the Tet/JBP family of 2-oxoglutarate- and iron-dependent dioxygenases further hydroxylating it to form 5-hydroxymethylcytosine (5hmC). These enzymes emerged first in bacteriophages and appear to have been transferred to eukaryotes on one or more occasions. Eukaryotes appear to have recruited three major types of DNA-binding domains (SRA/SAD, TAM/MBD, and CXXC) in discriminating DNA with methylated or unmethylated cytosines. Analysis of the domain architectures of these domains and the DNA methylases suggests that early in eukaryotic evolution they developed a close functional link with SET-domain methylases and Jumonji-related demethylases that operate on peptides in chromatin proteins. In several eukaryotes, other functional connections were elaborated in the form of various combinations between domains related to DNA methylation and those involved in ATP-dependent chromatin remodeling and RNAi. In certain eukaryotes, such as mammals and angiosperms, novel dependencies on the DNA methylation system emerged, which resulted in it affecting unexpected aspects of the biology of these organisms such as parent-offspring interactions. In genomic terms, this was reflected in the emergence of new proteins related to methylation, such as Stella. The well-developed methylation systems of certain heteroloboseans, stramenopiles, chlorophytes, and haptophyte indicate that these might be new model systems to explore the relevance of DNA modifications in eukaryotes.
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Zemach A, Zilberman D. Evolution of Eukaryotic DNA Methylation and the Pursuit of Safer Sex. Curr Biol 2010; 20:R780-5. [DOI: 10.1016/j.cub.2010.07.007] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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De novo assembly of a 40 Mb eukaryotic genome from short sequence reads: Sordaria macrospora, a model organism for fungal morphogenesis. PLoS Genet 2010; 6:e1000891. [PMID: 20386741 PMCID: PMC2851567 DOI: 10.1371/journal.pgen.1000891] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Accepted: 03/02/2010] [Indexed: 01/09/2023] Open
Abstract
Filamentous fungi are of great importance in ecology, agriculture, medicine, and biotechnology. Thus, it is not surprising that genomes for more than 100 filamentous fungi have been sequenced, most of them by Sanger sequencing. While next-generation sequencing techniques have revolutionized genome resequencing, e.g. for strain comparisons, genetic mapping, or transcriptome and ChIP analyses, de novo assembly of eukaryotic genomes still presents significant hurdles, because of their large size and stretches of repetitive sequences. Filamentous fungi contain few repetitive regions in their 30-90 Mb genomes and thus are suitable candidates to test de novo genome assembly from short sequence reads. Here, we present a high-quality draft sequence of the Sordaria macrospora genome that was obtained by a combination of Illumina/Solexa and Roche/454 sequencing. Paired-end Solexa sequencing of genomic DNA to 85-fold coverage and an additional 10-fold coverage by single-end 454 sequencing resulted in approximately 4 Gb of DNA sequence. Reads were assembled to a 40 Mb draft version (N50 of 117 kb) with the Velvet assembler. Comparative analysis with Neurospora genomes increased the N50 to 498 kb. The S. macrospora genome contains even fewer repeat regions than its closest sequenced relative, Neurospora crassa. Comparison with genomes of other fungi showed that S. macrospora, a model organism for morphogenesis and meiosis, harbors duplications of several genes involved in self/nonself-recognition. Furthermore, S. macrospora contains more polyketide biosynthesis genes than N. crassa. Phylogenetic analyses suggest that some of these genes may have been acquired by horizontal gene transfer from a distantly related ascomycete group. Our study shows that, for typical filamentous fungi, de novo assembly of genomes from short sequence reads alone is feasible, that a mixture of Solexa and 454 sequencing substantially improves the assembly, and that the resulting data can be used for comparative studies to address basic questions of fungal biology.
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The genome of Nectria haematococca: contribution of supernumerary chromosomes to gene expansion. PLoS Genet 2009; 5:e1000618. [PMID: 19714214 PMCID: PMC2725324 DOI: 10.1371/journal.pgen.1000618] [Citation(s) in RCA: 308] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Accepted: 07/27/2009] [Indexed: 11/19/2022] Open
Abstract
The ascomycetous fungus Nectria haematococca, (asexual name Fusarium solani), is a member of a group of >50 species known as the "Fusarium solani species complex". Members of this complex have diverse biological properties including the ability to cause disease on >100 genera of plants and opportunistic infections in humans. The current research analyzed the most extensively studied member of this complex, N. haematococca mating population VI (MPVI). Several genes controlling the ability of individual isolates of this species to colonize specific habitats are located on supernumerary chromosomes. Optical mapping revealed that the sequenced isolate has 17 chromosomes ranging from 530 kb to 6.52 Mb and that the physical size of the genome, 54.43 Mb, and the number of predicted genes, 15,707, are among the largest reported for ascomycetes. Two classes of genes have contributed to gene expansion: specific genes that are not found in other fungi including its closest sequenced relative, Fusarium graminearum; and genes that commonly occur as single copies in other fungi but are present as multiple copies in N. haematococca MPVI. Some of these additional genes appear to have resulted from gene duplication events, while others may have been acquired through horizontal gene transfer. The supernumerary nature of three chromosomes, 14, 15, and 17, was confirmed by their absence in pulsed field gel electrophoresis experiments of some isolates and by demonstrating that these isolates lacked chromosome-specific sequences found on the ends of these chromosomes. These supernumerary chromosomes contain more repeat sequences, are enriched in unique and duplicated genes, and have a lower G+C content in comparison to the other chromosomes. Although the origin(s) of the extra genes and the supernumerary chromosomes is not known, the gene expansion and its large genome size are consistent with this species' diverse range of habitats. Furthermore, the presence of unique genes on supernumerary chromosomes might account for individual isolates having different environmental niches.
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Singh PK, Iyer SV, Ramakrishnan M, Kasbekar DP. Chromosome segment duplications inNeurospora crassa: barren crosses beget fertile science. Bioessays 2009; 31:209-19. [DOI: 10.1002/bies.200800098] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Progressive loss of DNA methylation releases epigenetic gene silencing from a tandemly repeated maize Myb gene. Genetics 2008; 181:81-91. [PMID: 19001287 DOI: 10.1534/genetics.108.097170] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Maize pericarp color1 (p1) gene, which regulates phlobaphene biosynthesis in kernel pericarp and cob glumes, offers an excellent genetic system to study tissue-specific gene regulation. A multicopy p1 allele, P1-wr (white pericarp/red cob) is epigenetically regulated. Hypomethylation of P1-wr in the presence of Unstable factor for orange1 (Ufo1), leads to ectopic pigmentation of pericarp and other organs. The Ufo1-induced phenotypes show incomplete penetrance and poor expressivity: gain of pigmentation is observed only in a subset of plants carrying Ufo1 mutation, and the extent of pigmentation is highly variable. We show that Ufo1 induces progressive hypomethylation of P1-wr repeats over generations. After five generations of exposure to Ufo1, a 30-40% decrease in CG and CNG methylation was observed in an upstream enhancer and an intron region of P1-wr. Interestingly, such hypomethylation correlated with an increase in penetrance of the Ufo1-induced pigmentation phenotype from approximately 27 to 61%. Expressivity of the Ufo1-induced phenotype also improved markedly as indicated by increased uniformity of pericarp pigmentation in the later generations. Furthermore, the poor expressivity of the Uo1 is associated with mosaic methylation patterns of the P1-wr upstream enhancer in individual cells and distinct P1-wr gene copies. Finally, comparison of methylation among different tissues indicated that Ufo1 induces rapid CG and CNG hypomethylation of P1-wr repeats during plant development. Together, these data indicate that the poor penetrance and expressivity of Ufo1-induced phenotypes is caused by mosaicism of methylation, and progressive mitotic hypomethylation leads to improved meiotic heritability of the mutant phenotype. In duplicated genomes like maize, loss of an epigenetic regulator may produce mosaic patterns due to redundancy of epigenetic regulators and their target sequences. We show here that multiple developmental cycles may be required for complete disruption of suppressed epigenetic states and appearance of heritable phenotypes.
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40
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Lee DW, Freitag M, Selker EU, Aramayo R. A cytosine methyltransferase homologue is essential for sexual development in Aspergillus nidulans. PLoS One 2008; 3:e2531. [PMID: 18575630 PMCID: PMC2432034 DOI: 10.1371/journal.pone.0002531] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Accepted: 05/08/2008] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The genome defense processes RIP (repeat-induced point mutation) in the filamentous fungus Neurospora crassa, and MIP (methylation induced premeiotically) in the fungus Ascobolus immersus depend on proteins with DNA methyltransferase (DMT) domains. Nevertheless, these proteins, RID and Masc1, respectively, have not been demonstrated to have DMT activity. We discovered a close homologue in Aspergillus nidulans, a fungus thought to have no methylation and no genome defense system comparable to RIP or MIP. PRINCIPAL FINDINGS We report the cloning and characterization of the DNA methyltransferase homologue A (dmtA) gene from Aspergillus nidulans. We found that the dmtA locus encodes both a sense (dmtA) and an anti-sense transcript (tmdA). Both transcripts are expressed in vegetative, conidial and sexual tissues. We determined that dmtA, but not tmdA, is required for early sexual development and formation of viable ascospores. We also tested if DNA methylation accumulated in any of the dmtA/tmdA mutants we constructed, and found that in both asexual and sexual tissues, these mutants, just like wild-type strains, appear devoid of DNA methylation. CONCLUSIONS/SIGNIFICANCE Our results demonstrate that a DMT homologue closely related to proteins implicated in RIP and MIP has an essential developmental function in a fungus that appears to lack both DNA methylation and RIP or MIP. It remains formally possible that DmtA is a bona fide DMT, responsible for trace, undetected DNA methylation that is restricted to a few cells or transient but our work supports the idea that the DMT domain present in the RID/Masc1/DmtA family has a previously undescribed function.
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Affiliation(s)
- Dong W. Lee
- Department of Biology, College of Science, Texas A&M University, College Station, Texas, United States of America
| | - Michael Freitag
- Department of Biology, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Eric U. Selker
- Department of Biology, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Rodolfo Aramayo
- Department of Biology, College of Science, Texas A&M University, College Station, Texas, United States of America
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Espagne E, Lespinet O, Malagnac F, Da Silva C, Jaillon O, Porcel BM, Couloux A, Aury JM, Ségurens B, Poulain J, Anthouard V, Grossetete S, Khalili H, Coppin E, Déquard-Chablat M, Picard M, Contamine V, Arnaise S, Bourdais A, Berteaux-Lecellier V, Gautheret D, de Vries RP, Battaglia E, Coutinho PM, Danchin EG, Henrissat B, Khoury RE, Sainsard-Chanet A, Boivin A, Pinan-Lucarré B, Sellem CH, Debuchy R, Wincker P, Weissenbach J, Silar P. The genome sequence of the model ascomycete fungus Podospora anserina. Genome Biol 2008; 9:R77. [PMID: 18460219 PMCID: PMC2441463 DOI: 10.1186/gb-2008-9-5-r77] [Citation(s) in RCA: 233] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Revised: 02/12/2008] [Accepted: 05/06/2008] [Indexed: 12/13/2022] Open
Abstract
A 10X draft sequence of Podospora anserina genome shows highly dynamic evolution since its divergence from Neurospora crassa. Background The dung-inhabiting ascomycete fungus Podospora anserina is a model used to study various aspects of eukaryotic and fungal biology, such as ageing, prions and sexual development. Results We present a 10X draft sequence of P. anserina genome, linked to the sequences of a large expressed sequence tag collection. Similar to higher eukaryotes, the P. anserina transcription/splicing machinery generates numerous non-conventional transcripts. Comparison of the P. anserina genome and orthologous gene set with the one of its close relatives, Neurospora crassa, shows that synteny is poorly conserved, the main result of evolution being gene shuffling in the same chromosome. The P. anserina genome contains fewer repeated sequences and has evolved new genes by duplication since its separation from N. crassa, despite the presence of the repeat induced point mutation mechanism that mutates duplicated sequences. We also provide evidence that frequent gene loss took place in the lineages leading to P. anserina and N. crassa. P. anserina contains a large and highly specialized set of genes involved in utilization of natural carbon sources commonly found in its natural biotope. It includes genes potentially involved in lignin degradation and efficient cellulose breakdown. Conclusion The features of the P. anserina genome indicate a highly dynamic evolution since the divergence of P. anserina and N. crassa, leading to the ability of the former to use specific complex carbon sources that match its needs in its natural biotope.
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Affiliation(s)
- Eric Espagne
- Univ Paris-Sud, Institut de Génétique et Microbiologie, UMR8621, 91405 Orsay cedex, France
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Repeat induced point mutation in two asexual fungi, Aspergillus niger and Penicillium chrysogenum. Curr Genet 2008; 53:287-97. [PMID: 18347798 DOI: 10.1007/s00294-008-0185-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 02/25/2008] [Accepted: 03/02/2008] [Indexed: 01/28/2023]
Abstract
Repeat induced point mutation (RIP) is a gene silencing mechanism present in fungal genomes. During RIP, duplicated sequences are efficiently and irreversibly mutated by transitions from C:G to T:A. For the first time, we have identified traces of RIP in transposable elements of Aspergillus niger and Penicillium chrysogenum, two biotechnologically relevant fungi. We found that RIP in P. chrysogenum has affected a large set of sequences, which also contain other mutations. On the other hand, RIP in A. niger is limited to only few sequences, but literally all mutations are RIP-like. Surprisingly, RIP occurred only in transposon sequences that have disrupted open reading frames in A. niger, a phenomenon not yet reported for other fungi. In both fungal species, we identified two sequences with strong sequence similarity to Neurospora crassa RID. RID is a putative DNA methyltransferase and the only known enzyme involved in the RIP process. Our findings suggest that both A. niger and P. chrysogenum either had a sexual past or have a sexual potential. These findings have important implications for future strain development of these fungi.
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Iyer LM, Anantharaman V, Wolf MY, Aravind L. Comparative genomics of transcription factors and chromatin proteins in parasitic protists and other eukaryotes. Int J Parasitol 2007; 38:1-31. [PMID: 17949725 DOI: 10.1016/j.ijpara.2007.07.018] [Citation(s) in RCA: 192] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 07/26/2007] [Accepted: 07/30/2007] [Indexed: 11/18/2022]
Abstract
Comparative genomics of parasitic protists and their free-living relatives are profoundly impacting our understanding of the regulatory systems involved in transcription and chromatin dynamics. While some parts of these systems are highly conserved, other parts are rapidly evolving, thereby providing the molecular basis for the variety in the regulatory adaptations of eukaryotes. The gross number of specific transcription factors and chromatin proteins are positively correlated with proteome size in eukaryotes. However, the individual types of specific transcription factors show an enormous variety across different eukaryotic lineages. The dominant families of specific transcription factors even differ between sister lineages, and have been shaped by gene loss and lineage-specific expansions. Recognition of this principle has helped in identifying the hitherto unknown, major specific transcription factors of several parasites, such as apicomplexans, Entamoeba histolytica, Trichomonas vaginalis, Phytophthora and ciliates. Comparative analysis of predicted chromatin proteins from protists allows reconstruction of the early evolutionary history of histone and DNA modification, nucleosome assembly and chromatin-remodeling systems. Many key catalytic, peptide-binding and DNA-binding domains in these systems ultimately had bacterial precursors, but were put together into distinctive regulatory complexes that are unique to the eukaryotes. In the case of histone methylases, histone demethylases and SWI2/SNF2 ATPases, proliferation of paralogous families followed by acquisition of novel domain architectures, seem to have played a major role in producing a diverse set of enzymes that create and respond to an epigenetic code of modified histones. The diversification of histone acetylases and DNA methylases appears to have proceeded via repeated emergence of new versions, most probably via transfers from bacteria to different eukaryotic lineages, again resulting in lineage-specific diversity in epigenetic signals. Even though the key histone modifications are universal to eukaryotes, domain architectures of proteins binding post-translationally modified-histones vary considerably across eukaryotes. This indicates that the histone code might be "interpreted" differently from model organisms in parasitic protists and their relatives. The complexity of domain architectures of chromatin proteins appears to have increased during eukaryotic evolution. Thus, Trichomonas, Giardia, Naegleria and kinetoplastids have relatively simple domain architectures, whereas apicomplexans and oomycetes have more complex architectures. RNA-dependent post-transcriptional silencing systems, which interact with chromatin-level regulatory systems, show considerable variability across parasitic protists, with complete loss in many apicomplexans and partial loss in Trichomonas vaginalis. This evolutionary synthesis offers a robust scaffold for future investigation of transcription and chromatin structure in parasitic protists.
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Affiliation(s)
- Lakshminarayan M Iyer
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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Hutter B, Helms V, Paulsen M. Tandem repeats in the CpG islands of imprinted genes. Genomics 2006; 88:323-32. [PMID: 16690248 DOI: 10.1016/j.ygeno.2006.03.019] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 03/24/2006] [Accepted: 03/30/2006] [Indexed: 11/26/2022]
Abstract
In contrast to most genes in mammalian genomes, imprinted genes are monoallelically expressed depending on the parental origin of the alleles. Imprinted gene expression is regulated by distinct DNA elements that exhibit allele-specific epigenetic modifications, such as DNA methylation. These so-called differentially methylated regions frequently overlap with CpG islands. Thus, CpG islands of imprinted genes may contain special DNA elements that distinguish them from CpG islands of biallelically expressed genes. Here, we present a detailed study of CpG islands of imprinted genes in mouse and in human. Our study shows that imprinted genes more frequently contain tandem repeat arrays in their CpG islands than randomly selected genes in both species. In addition, mouse imprinted genes more frequently possess intragenic CpG islands that may serve as promoters of allele-specific antisense transcripts. This feature is much less pronounced in human, indicating an interspecies variability in the evolution of imprinting control elements.
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Affiliation(s)
- Barbara Hutter
- Bioinformatik, FR 8.3 Biowissenschaften, Universität des Saarlandes, Postfach 151150, D-66041 Saarbrücken, Germany
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45
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Walter J, Hutter B, Khare T, Paulsen M. Repetitive elements in imprinted genes. Cytogenet Genome Res 2006; 113:109-15. [PMID: 16575169 DOI: 10.1159/000090821] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Accepted: 10/19/2005] [Indexed: 11/19/2022] Open
Abstract
Genomic imprinting in mammals results in mono-allelic expression of about 80 genes depending on the parental origin of the alleles. Though the epigenetic mechanisms underlying imprinting are rather clear, little is known about the genetic basis for these epigenetic mechanisms. It is still rather enigmatic which sequence features discriminate imprinted from non-imprinted genes/regions and why and how certain sequence elements are recognized and differentially marked in the germlines. It seems likely that specific DNA elements serve as signatures that guide the necessary epigenetic modification machineries to the imprinted regions. Inter- and intraspecific comparative genomic studies suggest that the unusual occurrence and distribution of various types of repetitive elements within imprinted regions may represent such genomic imprinting signatures. In this review we summarize the various observations made and discuss them in light of experimental data.
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Affiliation(s)
- J Walter
- Genetik/Epigenetik, FR 8.3 Biowissenschaften, Universitat des Saarlandes, Saarbrucken, Germany
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46
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Zickler D. From early homologue recognition to synaptonemal complex formation. Chromosoma 2006; 115:158-74. [PMID: 16570189 DOI: 10.1007/s00412-006-0048-6] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Revised: 12/20/2005] [Accepted: 12/21/2005] [Indexed: 10/24/2022]
Abstract
This review focuses on various aspects of chromosome homology searching and their relationship to meiotic and vegetative pairing and to the silencing of unpaired copies of genes. Chromosome recognition and pairing is a prominent characteristic of meiosis; however, for some organisms, this association (complete or partial) is also a normal part of nuclear organization. The multiple mechanisms suggested to contribute to homologous pairing are analyzed. Recognition of DNA/DNA homology also plays an important role in detecting DNA segments that are present in inappropriate number of copies before and during meiosis. In this context, the mechanisms of methylation induced premeiotically, repeat-induced point mutation, meiotic silencing by unpaired DNA, and meiotic sex chromosome inactivation will be discussed. Homologue juxtaposition during meiotic prophase can be divided into three mechanistically distinct steps, namely, recognition, presynaptic alignment, and synapsis by the synaptonemal complex (SC). In most organisms, these three steps are distinguished by their dependence on DNA double-strand breaks (DSBs). The coupling of SC initiation to (and downstream effects of) DSB formation and the exceptions to this dependency are discussed. Finally, this review addresses the specific factors that appear to promote chromosome movement at various stages of meiotic prophase, most particularly at the bouquet stage, and on their significance for homologue pairing and/or achieving a final pachytene configuration.
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Affiliation(s)
- Denise Zickler
- Université Paris-Sud, Institut de Génétique et Microbiologie, 91405, Orsay, France.
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Montiel MD, Lee HA, Archer DB. Evidence of RIP (repeat-induced point mutation) in transposase sequences of Aspergillus oryzae. Fungal Genet Biol 2006; 43:439-45. [PMID: 16531081 DOI: 10.1016/j.fgb.2006.01.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Revised: 01/06/2006] [Accepted: 01/26/2006] [Indexed: 11/20/2022]
Abstract
A DNA methyl-binding column was used to isolate genomic fragments enriched for DNA-methylation from Aspergillus parasiticus. One of the isolated sequences presented 67% identity at the protein level with the transposase from the transposable element Tan1 of Aspergillus niger var. awamori, and was found to be present in at least 20 copies in the Aspergillus oryzae database. Analysis of four copies showed evidence of C:G to T:A transitions in at least 98.2% of the mutations found over a 1,032-1,180 bp region spanning a large part of the transposase sequence. Using copy specific primers three sequences were amplified from a different strain of A. oryzae and a similar pattern of C:G to T:A transitions was found. These transitions are similar to those observed in RIP, in Neurospora crassa, where cytosine-methylation is believed to be involved. Using methylation-sensitive Southern blotting, no evidence of methylation was found in the transposase sequences in these two A. oryzae strains as well as one A. parasiticus and one Aspergillus flavus strain.
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Affiliation(s)
- Maria D Montiel
- Institute of Genetics, School of Biology, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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Abstract
Cytosine methylation is a common form of post-replicative DNA modification seen in both bacteria and eukaryotes. Modified cytosines have long been known to act as hotspots for mutations due to the high rate of spontaneous deamination of this base to thymine, resulting in a G/T mismatch. This will be fixed as a C-->T transition after replication if not repaired by the base excision repair (BER) pathway or specific repair enzymes dedicated to this purpose. This hypermutability has led to depletion of the target dinucleotide CpG outside of special CpG islands in mammals, which are normally unmethylated. We review the importance of C-->T transitions at non-island CpGs in human disease: When these occur in the germline, they are a common cause of inherited diseases such as epidermolysis bullosa and mucopolysaccharidosis, while in the soma they are frequently found in the genes for tumor suppressors such as p53 and the retinoblastoma protein, causing cancer. We also examine the specific repair enzymes involved, namely the endonuclease Vsr in Escherichia coli and two members of the uracil DNA glycosylase (UDG) superfamily in mammals, TDG and MBD4. Repair brings its own problems, since it will require remethylation of the replacement cytosine, presumably coupling repair to methylation by either the maintenance methylase Dnmt1 or a de novo enzyme such as Dnmt3a. Uncoupling of methylation from repair may be one way to remove methylation from DNA. We also look at the possible role of specific cytosine deaminases such as Aid and Apobec in accelerating deamination of methylcytosine and consequent DNA demethylation.
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Affiliation(s)
- C P Walsh
- Centre for Molecular Biosciences, School of Biomedical Sciences, University of Ulster, Northern Ireland
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Buryanov YI, Shevchuk TV. DNA methyltransferases and structural-functional specificity of eukaryotic DNA modification. BIOCHEMISTRY (MOSCOW) 2006; 70:730-42. [PMID: 16097936 DOI: 10.1007/s10541-005-0178-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Properties of the main families of mammalian, plant, and fungal DNA methyltransferases are considered. Structural-functional specificity of eukaryotic genome sequences methylated by DNA methyltransferases is characterized. The total methylation of cytosine in DNA sequences is described, as well as its relation with RNA interference. Mechanisms of regulation of expression and modulation of DNA methyltransferase activity in the eukaryotic cell are discussed.
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Affiliation(s)
- Ya I Buryanov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Pushchino Branch, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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Kapoor A, Agius F, Zhu JK. Preventing transcriptional gene silencing by active DNA demethylation. FEBS Lett 2005; 579:5889-98. [PMID: 16162337 DOI: 10.1016/j.febslet.2005.08.039] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2005] [Revised: 08/23/2005] [Accepted: 08/23/2005] [Indexed: 11/18/2022]
Abstract
DNA methylation is important for stable transcriptional gene silencing. DNA methyltransferases for de novo as well as maintenance methylation have been well characterized. However, enzymes responsible for active DNA demethylation have been elusive and several reported mechanisms of active demethylation have been controversial. There has been a critical need for genetic analysis in order to firmly establish an in vivo role for putative DNA demethylases. Mutations in the bifunctional DNA glycosylase/lyase ROS1 in Arabidopsis cause DNA hypermethylation and transcriptional silencing of specific genes. Recombinant ROS1 protein has DNA glycosylase/lyase activity on methylated but not unmethylated DNA substrates. Therefore, there is now strong genetic evidence supporting a base excision repair mechanism for active DNA demethylation. DNA demethylases may be critical factors for genome wide hypomethylation seen in cancers and possibly important for epigenetic reprogramming during somatic cell cloning and stem cell function.
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Affiliation(s)
- Avnish Kapoor
- Institute for Integrative Genome Biology, Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA 92521, USA
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