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Varassas SP, Amillis S, Pappas KM, Kouvelis VN. The Identification of the Mitochondrial DNA Polymerase γ (Mip1) of the Entomopathogenic Fungus Metarhizium brunneum. Microorganisms 2024; 12:1052. [PMID: 38930434 PMCID: PMC11205540 DOI: 10.3390/microorganisms12061052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2024] [Revised: 05/16/2024] [Accepted: 05/20/2024] [Indexed: 06/28/2024] Open
Abstract
Replication of the mitochondrial (mt) genome in filamentous fungi is under-studied, and knowledge is based mainly on data from yeasts and higher eukaryotes. In this study, the mitochondrial DNA polymerase γ (Mip1) of the entomopathogenic fungus Metarhizium brunneum is characterized and analyzed with disruption experiments and its in silico interactions with key proteins implicated in mt gene transcription, i.e., mt RNA polymerase Rpo41 and mt transcription factor Mtf1. Disruption of mip1 gene and its partial expression influences cell growth, morphology, germination and stress tolerance. A putative in silico model of Mip1-Rpo41-Mtf1, which is known to be needed for the initiation of replication, was proposed and helped to identify potential amino acid residues of Mip1 that interact with the Rpo41-Mtf1 complex. Moreover, the reduced expression of mip1 indicates that Mip1 is not required for efficient transcription but only for replication. Functional differences between the M. brunneum Mip1 and its counterparts from Saccharomyces cerevisiae and higher eukaryotes are discussed.
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Affiliation(s)
- Stylianos P. Varassas
- Section of Genetics and Biotechnology, Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece; (S.P.V.); (K.M.P.)
| | - Sotiris Amillis
- Section of Botany, Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece;
| | - Katherine M. Pappas
- Section of Genetics and Biotechnology, Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece; (S.P.V.); (K.M.P.)
| | - Vassili N. Kouvelis
- Section of Genetics and Biotechnology, Department of Biology, National and Kapodistrian University of Athens, 15784 Athens, Greece; (S.P.V.); (K.M.P.)
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Wolters JF, LaBella AL, Opulente DA, Rokas A, Hittinger CT. Mitochondrial genome diversity across the subphylum Saccharomycotina. Front Microbiol 2023; 14:1268944. [PMID: 38075892 PMCID: PMC10701893 DOI: 10.3389/fmicb.2023.1268944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 10/31/2023] [Indexed: 12/20/2023] Open
Abstract
Introduction Eukaryotic life depends on the functional elements encoded by both the nuclear genome and organellar genomes, such as those contained within the mitochondria. The content, size, and structure of the mitochondrial genome varies across organisms with potentially large implications for phenotypic variance and resulting evolutionary trajectories. Among yeasts in the subphylum Saccharomycotina, extensive differences have been observed in various species relative to the model yeast Saccharomyces cerevisiae, but mitochondrial genome sampling across many groups has been scarce, even as hundreds of nuclear genomes have become available. Methods By extracting mitochondrial assemblies from existing short-read genome sequence datasets, we have greatly expanded both the number of available genomes and the coverage across sparsely sampled clades. Results Comparison of 353 yeast mitochondrial genomes revealed that, while size and GC content were fairly consistent across species, those in the genera Metschnikowia and Saccharomyces trended larger, while several species in the order Saccharomycetales, which includes S. cerevisiae, exhibited lower GC content. Extreme examples for both size and GC content were scattered throughout the subphylum. All mitochondrial genomes shared a core set of protein-coding genes for Complexes III, IV, and V, but they varied in the presence or absence of mitochondrially-encoded canonical Complex I genes. We traced the loss of Complex I genes to a major event in the ancestor of the orders Saccharomycetales and Saccharomycodales, but we also observed several independent losses in the orders Phaffomycetales, Pichiales, and Dipodascales. In contrast to prior hypotheses based on smaller-scale datasets, comparison of evolutionary rates in protein-coding genes showed no bias towards elevated rates among aerobically fermenting (Crabtree/Warburg-positive) yeasts. Mitochondrial introns were widely distributed, but they were highly enriched in some groups. The majority of mitochondrial introns were poorly conserved within groups, but several were shared within groups, between groups, and even across taxonomic orders, which is consistent with horizontal gene transfer, likely involving homing endonucleases acting as selfish elements. Discussion As the number of available fungal nuclear genomes continues to expand, the methods described here to retrieve mitochondrial genome sequences from these datasets will prove invaluable to ensuring that studies of fungal mitochondrial genomes keep pace with their nuclear counterparts.
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Affiliation(s)
- John F. Wolters
- Laboratory of Genetics, DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Center for Genomic Science Innovation, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI, United States
| | - Abigail L. LaBella
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC, United States
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
| | - Dana A. Opulente
- Laboratory of Genetics, DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Center for Genomic Science Innovation, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI, United States
- Biology Department, Villanova University, Villanova, PA, United States
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
| | - Chris Todd Hittinger
- Laboratory of Genetics, DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Center for Genomic Science Innovation, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI, United States
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Waneka G, Stewart J, Anderson JR, Li W, Wilusz J, Argueso JL, Sloan DB. UV damage induces production of mitochondrial DNA fragments with specific length profiles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.07.566130. [PMID: 37986892 PMCID: PMC10659373 DOI: 10.1101/2023.11.07.566130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
UV light is a potent mutagen that induces bulky DNA damage in the form of cyclobutane pyrimidine dimers (CPDs). In eukaryotic cells, photodamage and other bulky lesions occurring in nuclear genomes (nucDNAs) can be repaired through nucleotide excision repair (NER), where dual incisions on both sides of a damaged site precede the removal of a single-stranded oligonucleotide containing the damage. Mitochondrial genomes (mtDNAs) are also susceptible to damage from UV light, but current views hold that the only way to eliminate bulky DNA damage in mtDNAs is through mtDNA degradation. Damage-containing oligonucleotides excised during NER can be captured with anti-damage antibodies and sequenced (XR-seq) to produce high resolution maps of active repair locations following UV exposure. We analyzed previously published datasets from Arabidopsis thaliana, Saccharomyces cerevisiae, and Drosophila melanogaster to identify reads originating from the mtDNA (and plastid genome in A. thaliana). In A. thaliana and S. cerevisiae, the mtDNA-mapping reads have unique length distributions compared to the nuclear-mapping reads. The dominant fragment size was 26 nt in S. cerevisiae and 28 nt in A. thaliana with distinct secondary peaks occurring in 2-nt (S. cerevisiae) or 4-nt (A. thaliana) intervals. These reads also show a nonrandom distribution of di-pyrimidines (the substrate for CPD formation) with TT enrichment at positions 7-8 of the reads. Therefore, UV damage to mtDNA appears to result in production of DNA fragments of characteristic lengths and positions relative to the damaged location. We hypothesize that these fragments may reflect the outcome of a previously uncharacterized mechanism of NER-like repair in mitochondria or a programmed mtDNA degradation pathway.
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Affiliation(s)
- Gus Waneka
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Joseph Stewart
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - John R Anderson
- Department of Microbiology, Immunology & Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Wentao Li
- Department of Environmental Health Science, University of Georgia, Athens, Georgia, USA
| | - Jeffrey Wilusz
- Department of Microbiology, Immunology & Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Juan Lucas Argueso
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
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Wolters JF, LaBella AL, Opulente DA, Rokas A, Hittinger CT. Mitochondrial Genome Diversity across the Subphylum Saccharomycotina. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.28.551029. [PMID: 37577532 PMCID: PMC10418067 DOI: 10.1101/2023.07.28.551029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Eukaryotic life depends on the functional elements encoded by both the nuclear genome and organellar genomes, such as those contained within the mitochondria. The content, size, and structure of the mitochondrial genome varies across organisms with potentially large implications for phenotypic variance and resulting evolutionary trajectories. Among yeasts in the subphylum Saccharomycotina, extensive differences have been observed in various species relative to the model yeast Saccharomyces cerevisiae, but mitochondrial genome sampling across many groups has been scarce, even as hundreds of nuclear genomes have become available. By extracting mitochondrial assemblies from existing short-read genome sequence datasets, we have greatly expanded both the number of available genomes and the coverage across sparsely sampled clades. Comparison of 353 yeast mitochondrial genomes revealed that, while size and GC content were fairly consistent across species, those in the genera Metschnikowia and Saccharomyces trended larger, while several species in the order Saccharomycetales, which includes S. cerevisiae, exhibited lower GC content. Extreme examples for both size and GC content were scattered throughout the subphylum. All mitochondrial genomes shared a core set of protein-coding genes for Complexes III, IV, and V, but they varied in the presence or absence of mitochondrially-encoded canonical Complex I genes. We traced the loss of Complex I genes to a major event in the ancestor of the orders Saccharomycetales and Saccharomycodales, but we also observed several independent losses in the orders Phaffomycetales, Pichiales, and Dipodascales. In contrast to prior hypotheses based on smaller-scale datasets, comparison of evolutionary rates in protein-coding genes showed no bias towards elevated rates among aerobically fermenting (Crabtree/Warburg-positive) yeasts. Mitochondrial introns were widely distributed, but they were highly enriched in some groups. The majority of mitochondrial introns were poorly conserved within groups, but several were shared within groups, between groups, and even across taxonomic orders, which is consistent with horizontal gene transfer, likely involving homing endonucleases acting as selfish elements. As the number of available fungal nuclear genomes continues to expand, the methods described here to retrieve mitochondrial genome sequences from these datasets will prove invaluable to ensuring that studies of fungal mitochondrial genomes keep pace with their nuclear counterparts.
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Affiliation(s)
- John F. Wolters
- Laboratory of Genetics, DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Center for Genomic Science Innovation, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI, 53726, USA
| | - Abigail L. LaBella
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte NC, 28223, USA
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA; Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN 37235, USA
| | - Dana A. Opulente
- Laboratory of Genetics, DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Center for Genomic Science Innovation, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI, 53726, USA
- Biology Department Villanova University, Villanova, PA 19085, USA
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA; Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN 37235, USA
| | - Chris Todd Hittinger
- Laboratory of Genetics, DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Center for Genomic Science Innovation, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI, 53726, USA
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Christinaki AC, Theelen B, Zania A, Coutinho SDA, Cabañes JF, Boekhout T, Kouvelis VN. Co-evolution of large inverted repeats and G-quadruplex DNA in fungal mitochondria may facilitate mitogenome stability: the case of Malassezia. Sci Rep 2023; 13:6308. [PMID: 37072481 PMCID: PMC10113387 DOI: 10.1038/s41598-023-33486-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/13/2023] [Indexed: 05/03/2023] Open
Abstract
Mitogenomes are essential due to their contribution to cell respiration. Recently they have also been implicated in fungal pathogenicity mechanisms. Members of the basidiomycetous yeast genus Malassezia are an important fungal component of the human skin microbiome, linked to various skin diseases, bloodstream infections, and they are increasingly implicated in gut diseases and certain cancers. In this study, the comparative analysis of Malassezia mitogenomes contributed to phylogenetic tree construction for all species. The mitogenomes presented significant size and gene order diversity which correlates to their phylogeny. Most importantly, they showed the inclusion of large inverted repeats (LIRs) and G-quadruplex (G4) DNA elements, rendering Malassezia mitogenomes a valuable test case for elucidating the evolutionary mechanisms responsible for this genome diversity. Both LIRs and G4s coexist and convergently evolved to provide genome stability through recombination. This mechanism is common in chloroplasts but, hitherto, rarely found in mitogenomes.
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Affiliation(s)
- Anastasia C Christinaki
- Section of Genetics and Biotechnology, Department of Biology, National and Kapodistrian University of Athens, Panepistimiopolis, 15771, Athens, Greece
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
| | - Bart Theelen
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
| | - Alkmini Zania
- Section of Genetics and Biotechnology, Department of Biology, National and Kapodistrian University of Athens, Panepistimiopolis, 15771, Athens, Greece
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
| | | | - Javier F Cabañes
- Veterinary Mycology Group, Department of Animal Health and Anatomy, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - Teun Boekhout
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
- College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Vassili N Kouvelis
- Section of Genetics and Biotechnology, Department of Biology, National and Kapodistrian University of Athens, Panepistimiopolis, 15771, Athens, Greece.
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