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Osborne M, Fubara A, Ó Cinnéide E, Coughlan AY, Wolfe KH. WHO elements - A new category of selfish genetic elements at the borderline between homing elements and transposable elements. Semin Cell Dev Biol 2024; 163:2-13. [PMID: 38664119 DOI: 10.1016/j.semcdb.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 04/02/2024] [Accepted: 04/04/2024] [Indexed: 05/26/2024]
Abstract
Homing genetic elements are a form of selfish DNA that inserts into a specific target site in the genome and spreads through the population by a process of biased inheritance. Two well-known types of homing element, called inteins and homing introns, were discovered decades ago. In this review we describe WHO elements, a newly discovered type of homing element that constitutes a distinct third category but is rare, having been found only in a few yeast species so far. WHO elements are inferred to spread using the same molecular homing mechanism as inteins and introns: they encode a site-specific endonuclease that cleaves the genome at the target site, making a DNA break that is subsequently repaired by copying the element. For most WHO elements, the target site is in the glycolytic gene FBA1. WHO elements differ from inteins and homing introns in two fundamental ways: they do not interrupt their host gene (FBA1), and they occur in clusters. The clusters were formed by successive integrations of different WHO elements into the FBA1 locus, the result of an 'arms race' between the endonuclease and its target site. We also describe one family of WHO elements (WHO10) that is no longer specifically associated with the FBA1 locus and instead appears to have become transposable, inserting at random genomic sites in Torulaspora globosa with up to 26 copies per strain. The WHO family of elements is therefore at the borderline between homing genetic elements and transposable elements.
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Affiliation(s)
- Matthieu Osborne
- Conway Institute and School of Medicine, University College Dublin, Dublin 4, Ireland
| | - Athaliah Fubara
- Conway Institute and School of Medicine, University College Dublin, Dublin 4, Ireland
| | - Eoin Ó Cinnéide
- Conway Institute and School of Medicine, University College Dublin, Dublin 4, Ireland
| | - Aisling Y Coughlan
- Conway Institute and School of Medicine, University College Dublin, Dublin 4, Ireland
| | - Kenneth H Wolfe
- Conway Institute and School of Medicine, University College Dublin, Dublin 4, Ireland.
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2
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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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Koster CC, Kleefeldt AA, van den Broek M, Luttik M, Daran JM, Daran-Lapujade P. Long-read direct RNA sequencing of the mitochondrial transcriptome of Saccharomyces cerevisiae reveals condition-dependent intron abundance. Yeast 2024; 41:256-278. [PMID: 37642136 DOI: 10.1002/yea.3893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/11/2023] [Accepted: 07/18/2023] [Indexed: 08/31/2023] Open
Abstract
Mitochondria fulfil many essential roles and have their own genome, which is expressed as polycistronic transcripts that undergo co- or posttranscriptional processing and splicing. Due to the inherent complexity and limited technical accessibility of the mitochondrial transcriptome, fundamental questions regarding mitochondrial gene expression and splicing remain unresolved, even in the model eukaryote Saccharomyces cerevisiae. Long-read sequencing could address these fundamental questions. Therefore, a method for the enrichment of mitochondrial RNA and sequencing using Nanopore technology was developed, enabling the resolution of splicing of polycistronic genes and the quantification of spliced RNA. This method successfully captured the full mitochondrial transcriptome and resolved RNA splicing patterns with single-base resolution and was applied to explore the transcriptome of S. cerevisiae grown with glucose or ethanol as the sole carbon source, revealing the impact of growth conditions on mitochondrial RNA expression and splicing. This study uncovered a remarkable difference in the turnover of Group II introns between yeast grown in either mostly fermentative or fully respiratory conditions. Whether this accumulation of introns in glucose medium has an impact on mitochondrial functions remains to be explored. Combined with the high tractability of the model yeast S. cerevisiae, the developed method enables to monitor mitochondrial transcriptome responses in a broad range of relevant contexts, including oxidative stress, apoptosis and mitochondrial diseases.
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Affiliation(s)
- Charlotte C Koster
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Askar A Kleefeldt
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Marcel van den Broek
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Marijke Luttik
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Jean-Marc Daran
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
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Golik P. RNA processing and degradation mechanisms shaping the mitochondrial transcriptome of budding yeasts. IUBMB Life 2024; 76:38-52. [PMID: 37596708 DOI: 10.1002/iub.2779] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 07/25/2023] [Indexed: 08/20/2023]
Abstract
Yeast mitochondrial genes are expressed as polycistronic transcription units that contain RNAs from different classes and show great evolutionary variability. The promoters are simple, and transcriptional control is rudimentary. Posttranscriptional mechanisms involving RNA maturation, stability, and degradation are thus the main force shaping the transcriptome and determining the expression levels of individual genes. Primary transcripts are fragmented by tRNA excision by RNase P and tRNase Z, additional processing events occur at the dodecamer site at the 3' end of protein-coding sequences. groups I and II introns are excised in a self-splicing reaction that is supported by protein splicing factors encoded by the nuclear genes, or by the introns themselves. The 3'-to-5' exoribonucleolytic complex called mtEXO is the main RNA degradation activity involved in RNA turnover and processing, supported by an auxiliary 5'-to-3' exoribonuclease Pet127p. tRNAs and, to a lesser extent, rRNAs undergo several different base modifications. This complex gene expression system relies on the coordinated action of mitochondrial and nuclear genes and undergoes rapid evolution, contributing to speciation events. Moving beyond the classical model yeast Saccharomyces cerevisiae to other budding yeasts should provide important insights into the coevolution of both genomes that constitute the eukaryotic genetic system.
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Affiliation(s)
- Pawel Golik
- Faculty of Biology, Institute of Genetics and Biotechnology, University of Warsaw, Warsaw, Poland
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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Kulik T, van Diepeningen AD, Hausner G. Editorial: The significance of mitogenomics in mycology, volume II. Front Microbiol 2023; 14:1344877. [PMID: 38192293 PMCID: PMC10773717 DOI: 10.3389/fmicb.2023.1344877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Accepted: 12/04/2023] [Indexed: 01/10/2024] Open
Affiliation(s)
- Tomasz Kulik
- Department of Botany and Nature Protection, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - Anne D. van Diepeningen
- B.U. Biointeractions and Plant Health, Wageningen Plant Research, Wageningen University and Research, Wageningen, Netherlands
| | - Georg Hausner
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
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Gilea AI, Magistrati M, Notaroberto I, Tiso N, Dallabona C, Baruffini E. The Saccharomyces cerevisiae mitochondrial DNA polymerase and its contribution to the knowledge about human POLG-related disorders. IUBMB Life 2023; 75:983-1002. [PMID: 37470284 DOI: 10.1002/iub.2770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/05/2023] [Indexed: 07/21/2023]
Abstract
Most eukaryotes possess a mitochondrial genome, called mtDNA. In animals and fungi, the replication of mtDNA is entrusted by the DNA polymerase γ, or Pol γ. The yeast Pol γ is composed only of a catalytic subunit encoded by MIP1. In humans, Pol γ is a heterotrimer composed of a catalytic subunit homolog to Mip1, encoded by POLG, and two accessory subunits. In the last 25 years, more than 300 pathological mutations in POLG have been identified as the cause of several mitochondrial diseases, called POLG-related disorders, which are characterized by multiple mtDNA deletions and/or depletion in affected tissues. In this review, at first, we summarize the biochemical properties of yeast Mip1, and how mutations, especially those introduced recently in the N-terminal and C-terminal regions of the enzyme, affect the in vitro activity of the enzyme and the in vivo phenotype connected to the mtDNA stability and to the mtDNA extended and point mutability. Then, we focus on the use of yeast harboring Mip1 mutations equivalent to the human ones to confirm their pathogenicity, identify the phenotypic defects caused by these mutations, and find both mechanisms and molecular compounds able to rescue the detrimental phenotype. A closing chapter will be dedicated to other polymerases found in yeast mitochondria, namely Pol ζ, Rev1 and Pol η, and to their genetic interactions with Mip1 necessary to maintain mtDNA stability and to avoid the accumulation of spontaneous or induced point mutations.
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Affiliation(s)
- Alexandru Ionut Gilea
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Martina Magistrati
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Ilenia Notaroberto
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Natascia Tiso
- Department of Biology, University of Padova, Padova, Italy
| | - Cristina Dallabona
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Enrico Baruffini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
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Mukhopadhyay J, Wai A, Hausner G. The mitogenomes of Leptographium aureum, Leptographium sp., and Grosmannia fruticeta: expansion by introns. Front Microbiol 2023; 14:1240407. [PMID: 37637121 PMCID: PMC10448965 DOI: 10.3389/fmicb.2023.1240407] [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: 06/15/2023] [Accepted: 07/26/2023] [Indexed: 08/29/2023] Open
Abstract
Introduction Many members of the Ophiostomatales are of economic importance as they are bark-beetle associates and causative agents for blue stain on timber and in some instances contribute towards tree mortality. The taxonomy of these fungi has been challenging due to the convergent evolution of many traits associated with insect dispersal and a limited number of morphological characters that happen to be highly pleomorphic. This study examines the mitochondrial genomes for three members of Leptographium sensu lato [Leptographium aureum (also known as Grosmannia aurea), Grosmannia fruticeta (also known as Leptographium fruticetum), and Leptographium sp. WIN(M)1376)]. Methods Illumina sequencing combined with gene and intron annotations and phylogenetic analysis were performed. Results Sequence analysis showed that gene content and gene synteny are conserved but mitochondrial genome sizes were variable: G. fruticeta at 63,821 bp, Leptographium sp. WIN(M)1376 at 81,823 bp and L. aureum at 104,547 bp. The variation in size is due to the number of introns and intron-associated open reading frames. Phylogenetic analysis of currently available mitochondrial genomes for members of the Ophiostomatales supports currently accepted generic arrangements within this order and specifically supports the separation of members with Leptographium-like conidiophores into two genera, with L. aureum grouping with Leptographium and G. fruticeta aligning with Grosmannia. Discussion Mitochondrial genomes are promising sequences for resolving evolutionary relationships within the Ophiostomatales.
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Affiliation(s)
| | | | - Georg Hausner
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
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Magistrati M, Gilea AI, Gerra MC, Baruffini E, Dallabona C. Drug Drop Test: How to Quickly Identify Potential Therapeutic Compounds for Mitochondrial Diseases Using Yeast Saccharomyces cerevisiae. Int J Mol Sci 2023; 24:10696. [PMID: 37445873 DOI: 10.3390/ijms241310696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/22/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
Mitochondrial diseases (MDs) refer to a group of clinically and genetically heterogeneous pathologies characterized by defective mitochondrial function and energy production. Unfortunately, there is no effective treatment for most MDs, and current therapeutic management is limited to relieving symptoms. The yeast Saccharomyces cerevisiae has been efficiently used as a model organism to study mitochondria-related disorders thanks to its easy manipulation and well-known mitochondrial biogenesis and metabolism. It has been successfully exploited both to validate alleged pathogenic variants identified in patients and to discover potential beneficial molecules for their treatment. The so-called "drug drop test", a phenotype-based high-throughput screening, especially if coupled with a drug repurposing approach, allows the identification of molecules with high translational potential in a cost-effective and time-saving manner. In addition to drug identification, S. cerevisiae can be used to point out the drug's target or pathway. To date, drug drop tests have been successfully carried out for a variety of disease models, leading to very promising results. The most relevant aspect is that studies on more complex model organisms confirmed the effectiveness of the drugs, strengthening the results obtained in yeast and demonstrating the usefulness of this screening as a novel approach to revealing new therapeutic molecules for MDs.
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Affiliation(s)
- Martina Magistrati
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Alexandru Ionut Gilea
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Maria Carla Gerra
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Enrico Baruffini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Cristina Dallabona
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
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9
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Nguyen THM, Tinz-Burdick A, Lenhardt M, Geertz M, Ramirez F, Schwartz M, Toledano M, Bonney B, Gaebler B, Liu W, Wolters JF, Chiu K, Fiumera AC, Fiumera HL. Mapping mitonuclear epistasis using a novel recombinant yeast population. PLoS Genet 2023; 19:e1010401. [PMID: 36989278 PMCID: PMC10085025 DOI: 10.1371/journal.pgen.1010401] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 04/10/2023] [Accepted: 03/10/2023] [Indexed: 03/30/2023] Open
Abstract
Genetic variation in mitochondrial and nuclear genomes can perturb mitonuclear interactions and lead to phenotypic differences between individuals and populations. Despite their importance to most complex traits, it has been difficult to identify the interacting mitonuclear loci. Here, we present a novel advanced intercrossed population of Saccharomyces cerevisiae yeasts, called the Mitonuclear Recombinant Collection (MNRC), designed explicitly for detecting mitonuclear loci contributing to complex traits. For validation, we focused on mapping genes that contribute to the spontaneous loss of mitochondrial DNA (mtDNA) that leads to the petite phenotype in yeast. We found that rates of petite formation in natural populations are variable and influenced by genetic variation in nuclear DNA, mtDNA and mitonuclear interactions. We mapped nuclear and mitonuclear alleles contributing to mtDNA stability using the MNRC by integrating a term for mitonuclear epistasis into a genome-wide association model. We found that the associated mitonuclear loci play roles in mitotic growth most likely responding to retrograde signals from mitochondria, while the associated nuclear loci with main effects are involved in genome replication. We observed a positive correlation between growth rates and petite frequencies, suggesting a fitness tradeoff between mitotic growth and mtDNA stability. We also found that mtDNA stability was correlated with a mobile mitochondrial GC-cluster that is present in certain populations of yeast and that selection for nuclear alleles that stabilize mtDNA may be rapidly occurring. The MNRC provides a powerful tool for identifying mitonuclear interacting loci that will help us to better understand genotype-phenotype relationships and coevolutionary trajectories.
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Affiliation(s)
- Tuc H M Nguyen
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
- Department of Biological Sciences, New York University, New York, New York, United States of America
| | - Austen Tinz-Burdick
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
| | - Meghan Lenhardt
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
| | - Margaret Geertz
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
| | - Franchesca Ramirez
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
| | - Mark Schwartz
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
| | - Michael Toledano
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
| | - Brooke Bonney
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
| | - Benjamin Gaebler
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
| | - Weiwei Liu
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
| | - John F Wolters
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
| | - Kenneth Chiu
- Department of Computer Sciences, Binghamton University, Binghamton, New York, United States of America
| | - Anthony C Fiumera
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
| | - Heather L Fiumera
- Department of Biological Sciences, Binghamton University, Binghamton, New York, United States of America
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10
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Visinoni F, Delneri D. Mitonuclear interplay in yeast: from speciation to phenotypic adaptation. Curr Opin Genet Dev 2022; 76:101957. [PMID: 35870233 DOI: 10.1016/j.gde.2022.101957] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/14/2022] [Accepted: 06/20/2022] [Indexed: 11/03/2022]
Abstract
Saccharomyces yeasts have evolved into an important model system to study mitonuclear incompatibilities, thanks to recent advances in the field of sequencing, yeast hybridisation and multigenerational breeding. Yeast hybrids contain two homologous proteomes but retain only one type of mitochondria allowing studies on the effect of mitochondria on phenotype and gene expression. Here, we discuss the recent developments in the growing field of yeast mitogenomics spanning from the impact that this organelle has in shaping yeast fitness and genome evolution to the dissection of molecular determinants of mitonuclear incompatibilities. Applying the state-of-the-art genetic tools to a broader range of natural yeast species from different environments will help progress the field and untap the mitochondrial potential in strain development.
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Affiliation(s)
- Federico Visinoni
- Manchester Institute of Biotechnology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Daniela Delneri
- Manchester Institute of Biotechnology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.
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11
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Overexpression of MRX9 impairs processing of RNAs encoding mitochondrial oxidative phosphorylation factors COB and COX1 in yeast. J Biol Chem 2022; 298:102214. [PMID: 35779633 PMCID: PMC9307953 DOI: 10.1016/j.jbc.2022.102214] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 11/24/2022] Open
Abstract
Mitochondrial translation is a highly regulated process, and newly synthesized mitochondrial products must first associate with several nuclear-encoded auxiliary factors to form oxidative phosphorylation complexes. The output of mitochondrial products should therefore be in stoichiometric equilibrium with the nuclear-encoded products to prevent unnecessary energy expense or the accumulation of pro-oxidant assembly modules. In the mitochondrial DNA of Saccharomyces cerevisiae, COX1 encodes subunit 1 of the cytochrome c oxidase and COB the central core of the cytochrome bc1 electron transfer complex; however, factors regulating the expression of these mitochondrial products are not completely described. Here, we identified Mrx9p as a new factor that controls COX1 and COB expression. We isolated MRX9 in a screen for mitochondrial factors that cause poor accumulation of newly synthesized Cox1p and compromised transition to the respiratory metabolism. Northern analyses indicated lower levels of COX1 and COB mature mRNAs accompanied by an accumulation of unprocessed transcripts in the presence of excess Mrx9p. In a strain devoid of mitochondrial introns, MRX9 overexpression did not affect COX1 and COB translation or respiratory adaptation, implying Mrx9p regulates processing of COX1 and COB RNAs. In addition, we found Mrx9p was localized in the mitochondrial inner membrane, facing the matrix, as a portion of it cosedimented with mitoribosome subunits and its removal or overexpression altered Mss51p sedimentation. Finally, we showed accumulation of newly synthesized Cox1p in the absence of Mrx9p was diminished in cox14 null mutants. Taken together, these data indicate a regulatory role of Mrx9p in COX1 RNA processing.
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12
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Zhang S, Wang S, Fang Z, Lang BF, Zhang YJ. Characterization of the mitogenome of Gongronella sp. w5 reveals substantial variation in Mucoromycota. Appl Microbiol Biotechnol 2022; 106:2587-2601. [PMID: 35318523 DOI: 10.1007/s00253-022-11880-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/24/2022] [Accepted: 03/06/2022] [Indexed: 11/02/2022]
Abstract
Gongronella is a genus of fungi in Mucorales (Mucoromycota). Some of its members have important biotechnological applications, but until now, not a single mitogenome has been characterized in Gongronella. Here, we present the complete mitogenome assembly of Gongronella sp. w5, a soil isolate known to interact with plants and several fungi. Its 36,593-bp circular mitogenome encodes the large and small subunit rRNAs, 14 standard mitochondrial proteins, 24 tRNAs, three free-standing ORF proteins, and the RNA subunit of RNase P (rnpB). These genes arrange in an order novel to known fungal mitogenomes. Three group I introns are present in the cob, cox1, and nad5 genes, respectively, and they are probably acquired by horizontal gene transfer. Phylogenetic analysis based on mitochondrion-encoded proteins supports the grouping of Gongronella sp. w5 with Absidia glauca, forming the Cunninghamellaceae clade within Mucoromycota. Gongronella and most other Mucoromycota species are predicted to use the standard genetic code in mitochondrial translation, rather than code 4 assigned by GenBank. A comparison among seven publicly available mitogenomes in Mucoromycota reveals the presence of the same 14 typical protein-coding genes plus rnpB, yet substantial variation in mitogenome size, intron number, gene order, and orientation. In this comparison, the uniqueness of Gongronella is evident from similarly large differences to its closest phylogenetic neighbor, A. glauca. This study promotes our understanding of fungal evolution in Mucoromycota. KEY POINTS: • This study reports the first mitogenome in Gongronella, which presents a novel gene order. • Different Mucoromycota mitogenomes show substantial variation of gene organizations. • Most Mucoromycota species use the standard genetic code to translate mitochondrial genes.
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Affiliation(s)
- Shu Zhang
- School of Life Science, Shanxi University, Taiyuan, 030006, China
| | - Shuang Wang
- School of Life Science, Shanxi University, Taiyuan, 030006, China
| | - Zemin Fang
- School of Life Sciences, Anhui University, Hefei, 230601, China.
| | - B Franz Lang
- Département de Biochimie, Centre Robert Cedergren, Université de Montréal, Montreal, Québec, H3T 1J4, Canada.
| | - Yong-Jie Zhang
- School of Life Science, Shanxi University, Taiyuan, 030006, China.
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13
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Hao W. From Genome Variation to Molecular Mechanisms: What we Have Learned From Yeast Mitochondrial Genomes? Front Microbiol 2022; 13:806575. [PMID: 35126340 PMCID: PMC8811140 DOI: 10.3389/fmicb.2022.806575] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 01/03/2022] [Indexed: 11/26/2022] Open
Abstract
Analysis of genome variation provides insights into mechanisms in genome evolution. This is increasingly appreciated with the rapid growth of genomic data. Mitochondrial genomes (mitogenomes) are well known to vary substantially in many genomic aspects, such as genome size, sequence context, nucleotide base composition and substitution rate. Such substantial variation makes mitogenomes an excellent model system to study the mechanisms dictating mitogenome variation. Recent sequencing efforts have not only covered a rich number of yeast species but also generated genomes from abundant strains within the same species. The rich yeast genomic data have enabled detailed investigation from genome variation into molecular mechanisms in genome evolution. This mini-review highlights some recent progresses in yeast mitogenome studies.
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14
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Hénault M, Marsit S, Charron G, Landry CR. Hybridization drives mitochondrial DNA degeneration and metabolic shift in a species with biparental mitochondrial inheritance. Genome Res 2022; 32:2043-2056. [PMID: 36351770 PMCID: PMC9808621 DOI: 10.1101/gr.276885.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 10/26/2022] [Indexed: 11/11/2022]
Abstract
Mitochondrial DNA (mtDNA) is a cytoplasmic genome that is essential for respiratory metabolism. Although uniparental mtDNA inheritance is most common in animals and plants, distinct mtDNA haplotypes can coexist in a state of heteroplasmy, either because of paternal leakage or de novo mutations. mtDNA integrity and the resolution of heteroplasmy have important implications, notably for mitochondrial genetic disorders, speciation, and genome evolution in hybrids. However, the impact of genetic variation on the transition to homoplasmy from initially heteroplasmic backgrounds remains largely unknown. Here, we use Saccharomyces yeasts, fungi with constitutive biparental mtDNA inheritance, to investigate the resolution of mtDNA heteroplasmy in a variety of hybrid genotypes. We previously designed 11 crosses along a gradient of parental evolutionary divergence using undomesticated isolates of Saccharomyces paradoxus and Saccharomyces cerevisiae Each cross was independently replicated 48 to 96 times, and the resulting 864 hybrids were evolved under relaxed selection for mitochondrial function. Genome sequencing of 446 MA lines revealed extensive mtDNA recombination, but the recombination rate was not predicted by parental divergence level. We found a strong positive relationship between parental divergence and the rate of large-scale mtDNA deletions, which led to the loss of respiratory metabolism. We also uncovered associations between mtDNA recombination, mtDNA deletion, and genome instability that were genotype specific. Our results show that hybridization in yeast induces mtDNA degeneration through large-scale deletion and loss of function, with deep consequences for mtDNA evolution, metabolism, and the emergence of reproductive isolation.
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Affiliation(s)
- Mathieu Hénault
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec, G1V 0A6, Canada;,Département de Biochimie, Microbiologie et Bioinformatique, Université Laval, Québec, Québec, G1V 0A6, Canada;,Quebec Network for Research on Protein Function, Engineering, and Applications (PROTEO), Université Laval, Québec, Québec, G1V 0A6, Canada;,Université Laval Big Data Research Center (BDRC_UL), Québec, Québec, G1V 0A6, Canada
| | - Souhir Marsit
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec, G1V 0A6, Canada;,Département de Biochimie, Microbiologie et Bioinformatique, Université Laval, Québec, Québec, G1V 0A6, Canada;,Quebec Network for Research on Protein Function, Engineering, and Applications (PROTEO), Université Laval, Québec, Québec, G1V 0A6, Canada;,Université Laval Big Data Research Center (BDRC_UL), Québec, Québec, G1V 0A6, Canada;,Département de Biologie, Université Laval, Québec, Québec, G1V 0A6, Canada
| | - Guillaume Charron
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec, G1V 0A6, Canada;,Quebec Network for Research on Protein Function, Engineering, and Applications (PROTEO), Université Laval, Québec, Québec, G1V 0A6, Canada;,Université Laval Big Data Research Center (BDRC_UL), Québec, Québec, G1V 0A6, Canada;,Département de Biologie, Université Laval, Québec, Québec, G1V 0A6, Canada
| | - Christian R. Landry
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec, G1V 0A6, Canada;,Département de Biochimie, Microbiologie et Bioinformatique, Université Laval, Québec, Québec, G1V 0A6, Canada;,Quebec Network for Research on Protein Function, Engineering, and Applications (PROTEO), Université Laval, Québec, Québec, G1V 0A6, Canada;,Université Laval Big Data Research Center (BDRC_UL), Québec, Québec, G1V 0A6, Canada;,Département de Biologie, Université Laval, Québec, Québec, G1V 0A6, Canada
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15
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Saccharomyces cerevisiae as a Tool for Studying Mutations in Nuclear Genes Involved in Diseases Caused by Mitochondrial DNA Instability. Genes (Basel) 2021; 12:genes12121866. [PMID: 34946817 PMCID: PMC8701800 DOI: 10.3390/genes12121866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/20/2021] [Accepted: 11/23/2021] [Indexed: 01/03/2023] Open
Abstract
Mitochondrial DNA (mtDNA) maintenance is critical for oxidative phosphorylation (OXPHOS) since some subunits of the respiratory chain complexes are mitochondrially encoded. Pathological mutations in nuclear genes involved in the mtDNA metabolism may result in a quantitative decrease in mtDNA levels, referred to as mtDNA depletion, or in qualitative defects in mtDNA, especially in multiple deletions. Since, in the last decade, most of the novel mutations have been identified through whole-exome sequencing, it is crucial to confirm the pathogenicity by functional analysis in the appropriate model systems. Among these, the yeast Saccharomyces cerevisiae has proved to be a good model for studying mutations associated with mtDNA instability. This review focuses on the use of yeast for evaluating the pathogenicity of mutations in six genes, MPV17/SYM1, MRM2/MRM2, OPA1/MGM1, POLG/MIP1, RRM2B/RNR2, and SLC25A4/AAC2, all associated with mtDNA depletion or multiple deletions. We highlight the techniques used to construct a specific model and to measure the mtDNA instability as well as the main results obtained. We then report the contribution that yeast has given in understanding the pathogenic mechanisms of the mutant variants, in finding the genetic suppressors of the mitochondrial defects and in the discovery of molecules able to improve the mtDNA stability.
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16
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Abstract
While sequencing and characterizing the mitochondrial genomes of 71 strains from the yeast genus Metschnikowia [1] (close cousin to the model species Candida albicans), we uncovered one of the most extreme examples of mitochondrial genome architectural diversity observed to date. These Metschnikowia mitochondrial DNAs (mtDNAs) capture nearly the entire known gene-size and intron-content range for cox1 and cob across all eukaryotic life and show remarkable differences in structure and noncoding content. This genomic variation can be seen both among species and between strains of the same species, raising the question: why are Metschnikowia mitogenomes so malleable?
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17
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Mitochondrial Genomic Landscape: A Portrait of the Mitochondrial Genome 40 Years after the First Complete Sequence. Life (Basel) 2021; 11:life11070663. [PMID: 34357035 PMCID: PMC8303319 DOI: 10.3390/life11070663] [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: 06/15/2021] [Revised: 07/02/2021] [Accepted: 07/03/2021] [Indexed: 12/11/2022] Open
Abstract
Notwithstanding the initial claims of general conservation, mitochondrial genomes are a largely heterogeneous set of organellar chromosomes which displays a bewildering diversity in terms of structure, architecture, gene content, and functionality. The mitochondrial genome is typically described as a single chromosome, yet many examples of multipartite genomes have been found (for example, among sponges and diplonemeans); the mitochondrial genome is typically depicted as circular, yet many linear genomes are known (for example, among jellyfish, alveolates, and apicomplexans); the chromosome is normally said to be “small”, yet there is a huge variation between the smallest and the largest known genomes (found, for example, in ctenophores and vascular plants, respectively); even the gene content is highly unconserved, ranging from the 13 oxidative phosphorylation-related enzymatic subunits encoded by animal mitochondria to the wider set of mitochondrial genes found in jakobids. In the present paper, we compile and describe a large database of 27,873 mitochondrial genomes currently available in GenBank, encompassing the whole eukaryotic domain. We discuss the major features of mitochondrial molecular diversity, with special reference to nucleotide composition and compositional biases; moreover, the database is made publicly available for future analyses on the MoZoo Lab GitHub page.
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18
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Doyle JJ. Defining coalescent genes: Theory meets practice in organelle phylogenomics. Syst Biol 2021; 71:476-489. [PMID: 34191012 DOI: 10.1093/sysbio/syab053] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/24/2021] [Accepted: 06/28/2021] [Indexed: 11/13/2022] Open
Abstract
The species tree paradigm that dominates current molecular systematic practice infers species trees from collections of sequences under assumptions of the multispecies coalescent (MSC), i.e., that there is free recombination between the sequences and no (or very low) recombination within them. These coalescent genes (c-genes) are thus defined in an historical rather than molecular sense, and can in theory be as large as an entire genome or as small as a single nucleotide. A debate about how to define c-genes centers on the contention that nuclear gene sequences used in many coalescent analyses undergo too much recombination, such that their introns comprise multiple c-genes, violating a key assumption of the MSC. Recently a similar argument has been made for the genes of plastid (e.g., chloroplast) and mitochondrial genomes, which for the last 30 or more years have been considered to represent a single c-gene for the purposes of phylogeny reconstruction because they are non-recombining in a historical sense. Consequently, it has been suggested that these genomes should be analyzed using coalescent methods that treat their genes-over 70 protein-coding genes in the case of most plastid genomes (plastomes)-as independent estimates of species phylogeny, in contrast to the usual practice of concatenation, which is appropriate for generating gene trees. However, although recombination certainly occurs in the plastome, as has been recognized since the 1970's, it is unlikely to be phylogenetically relevant. This is because such historically effective recombination can only occur when plastomes with incongruent histories are brought together in the same plastid. However, plastids sort rapidly into different cell lineages and rarely fuse. Thus, because of plastid biology, the plastome is a more canonical c-gene than is the average multi-intron mammalian nuclear gene. The plastome should thus continue to be treated as a single estimate of the underlying species phylogeny, as should the mitochondrial genome. The implications of this long-held insight of molecular systematics for studies in the phylogenomic era are explored.
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Affiliation(s)
- Jeff J Doyle
- Plant Biology Section, Plant Breeding & Genetics Section, and L. H. Bailey Hortorium, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853 USA
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19
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Barbitoff YA, Matveenko AG, Matiiv AB, Maksiutenko EM, Moskalenko SE, Drozdova PB, Polev DE, Beliavskaia AY, Danilov LG, Predeus AV, Zhouravleva GA. Chromosome-level genome assembly and structural variant analysis of two laboratory yeast strains from the Peterhof Genetic Collection lineage. G3-GENES GENOMES GENETICS 2021; 11:6129118. [PMID: 33677552 PMCID: PMC8759820 DOI: 10.1093/g3journal/jkab029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 01/22/2021] [Indexed: 01/23/2023]
Abstract
Thousands of yeast genomes have been sequenced with both traditional and long-read technologies, and multiple observations about modes of genome evolution for both wild and laboratory strains have been drawn from these sequences. In our study, we applied Oxford Nanopore and Illumina technologies to assemble complete genomes of two widely used members of a distinct laboratory yeast lineage, the Peterhof Genetic Collection (PGC), and investigate the structural features of these genomes including transposable element content, copy number alterations, and structural rearrangements. We identified numerous notable structural differences between genomes of PGC strains and the reference S288C strain. We discovered a substantial enrichment of mid-length insertions and deletions within repetitive coding sequences, such as in the SCH9 gene or the NUP100 gene, with possible impact of these variants on protein amyloidogenicity. High contiguity of the final assemblies allowed us to trace back the history of reciprocal unbalanced translocations between chromosomes I, VIII, IX, XI, and XVI of the PGC strains. We show that formation of hybrid alleles of the FLO genes during such chromosomal rearrangements is likely responsible for the lack of invasive growth of yeast strains. Taken together, our results highlight important features of laboratory yeast strain evolution using the power of long-read sequencing.
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Affiliation(s)
- Yury A Barbitoff
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia.,Bioinformatics Institute, St. Petersburg 197342, Russia
| | - Andrew G Matveenko
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia.,Bioinformatics Institute, St. Petersburg 197342, Russia
| | - Anton B Matiiv
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia.,Bioinformatics Institute, St. Petersburg 197342, Russia
| | - Evgeniia M Maksiutenko
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia.,St. Petersburg Branch, Vavilov Institute of General Genetics of the Russian Academy of Sciences, St. Petersburg 199034, Russia
| | - Svetlana E Moskalenko
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia.,St. Petersburg Branch, Vavilov Institute of General Genetics of the Russian Academy of Sciences, St. Petersburg 199034, Russia
| | | | | | - Alexandra Y Beliavskaia
- Department of Invertebrate Zoology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Lavrentii G Danilov
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia
| | - Alexander V Predeus
- Bioinformatics Institute, St. Petersburg 197342, Russia.,University of Liverpool, Liverpool, UK, L7 3EA
| | - Galina A Zhouravleva
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia
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20
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Plazzi F, Puccio G, Passamonti M. HERMES: An improved method to test mitochondrial genome molecular synapomorphies among clades. Mitochondrion 2021; 58:285-295. [PMID: 33639269 DOI: 10.1016/j.mito.2021.02.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 01/10/2021] [Accepted: 02/12/2021] [Indexed: 02/06/2023]
Abstract
Mitochondrial chromosomes have diversified among eukaryotes and many different architectures and features are now acknowledged for this genome. Here we present the improved HERMES index, which can measure and quantify the amount of molecular change experienced by mitochondrial genomes. We test the improved approach with ten molecular phylogenetic studies based on complete mitochondrial genomes, representing six bilaterian Phyla. In most cases, HERMES analysis spotted out clades or single species with peculiar molecular synapomorphies, allowing to identify phylogenetic and ecological patterns. The software presented herein handles linear, circular, and multi-chromosome genomes, thus widening the HERMES scope to the complete eukaryotic domain.
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Affiliation(s)
- Federico Plazzi
- Department of Biological, Geological and Environmental Sciences, University of Bologna, via Selmi, 3, 40126 Bologna, Italy.
| | - Guglielmo Puccio
- Department of Biological, Geological and Environmental Sciences, University of Bologna, via Selmi, 3, 40126 Bologna, Italy.
| | - Marco Passamonti
- Department of Biological, Geological and Environmental Sciences, University of Bologna, via Selmi, 3, 40126 Bologna, Italy.
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21
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Ceccatelli Berti C, di Punzio G, Dallabona C, Baruffini E, Goffrini P, Lodi T, Donnini C. The Power of Yeast in Modelling Human Nuclear Mutations Associated with Mitochondrial Diseases. Genes (Basel) 2021; 12:300. [PMID: 33672627 PMCID: PMC7924180 DOI: 10.3390/genes12020300] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 12/17/2022] Open
Abstract
The increasing application of next generation sequencing approaches to the analysis of human exome and whole genome data has enabled the identification of novel variants and new genes involved in mitochondrial diseases. The ability of surviving in the absence of oxidative phosphorylation (OXPHOS) and mitochondrial genome makes the yeast Saccharomyces cerevisiae an excellent model system for investigating the role of these new variants in mitochondrial-related conditions and dissecting the molecular mechanisms associated with these diseases. The aim of this review was to highlight the main advantages offered by this model for the study of mitochondrial diseases, from the validation and characterisation of novel mutations to the dissection of the role played by genes in mitochondrial functionality and the discovery of potential therapeutic molecules. The review also provides a summary of the main contributions to the understanding of mitochondrial diseases emerged from the study of this simple eukaryotic organism.
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Affiliation(s)
| | | | | | | | | | | | - Claudia Donnini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy; (C.C.B.); (G.d.P.); (C.D.); (E.B.); (P.G.); (T.L.)
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22
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Smukowski Heil C, Patterson K, Hickey ASM, Alcantara E, Dunham MJ. Transposable Element Mobilization in Interspecific Yeast Hybrids. Genome Biol Evol 2021; 13:6141023. [PMID: 33595639 PMCID: PMC7952228 DOI: 10.1093/gbe/evab033] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2021] [Indexed: 12/13/2022] Open
Abstract
Barbara McClintock first hypothesized that interspecific hybridization could provide a “genomic shock” that leads to the mobilization of transposable elements (TEs). This hypothesis is based on the idea that regulation of TE movement is potentially disrupted in hybrids. However, the handful of studies testing this hypothesis have yielded mixed results. Here, we set out to identify if hybridization can increase transposition rate and facilitate colonization of TEs in Saccharomyces cerevisiae × Saccharomyces uvarum interspecific yeast hybrids. Saccharomyces cerevisiae have a small number of active long terminal repeat retrotransposons (Ty elements), whereas their distant relative S. uvarum have lost the Ty elements active in S. cerevisiae. Although the regulation system of Ty elements is known in S. cerevisiae, it is unclear how Ty elements are regulated in other Saccharomyces species, and what mechanisms contributed to the loss of most classes of Ty elements in S. uvarum. Therefore, we first assessed whether TEs could insert in the S. uvarum sub-genome of a S. cerevisiae × S. uvarum hybrid. We induced transposition to occur in these hybrids and developed a sequencing technique to show that Ty elements insert readily and nonrandomly in the S. uvarum genome. We then used an in vivo reporter construct to directly measure transposition rate in hybrids, demonstrating that hybridization itself does not alter rate of mobilization. However, we surprisingly show that species-specific mitochondrial inheritance can change transposition rate by an order of magnitude. Overall, our results provide evidence that hybridization can potentially facilitate the introduction of TEs across species boundaries and alter transposition via mitochondrial transmission, but that this does not lead to unrestrained proliferation of TEs suggested by the genomic shock theory.
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Affiliation(s)
- Caiti Smukowski Heil
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Kira Patterson
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | | | - Erica Alcantara
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Maitreya J Dunham
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
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23
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Nguyen THM, Sondhi S, Ziesel A, Paliwal S, Fiumera HL. Mitochondrial-nuclear coadaptation revealed through mtDNA replacements in Saccharomyces cerevisiae. BMC Evol Biol 2020; 20:128. [PMID: 32977769 PMCID: PMC7517635 DOI: 10.1186/s12862-020-01685-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/07/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mitochondrial function requires numerous genetic interactions between mitochondrial- and nuclear- encoded genes. While selection for optimal mitonuclear interactions should result in coevolution between both genomes, evidence for mitonuclear coadaptation is challenging to document. Genetic models where mitonuclear interactions can be explored are needed. RESULTS We systematically exchanged mtDNAs between 15 Saccharomyces cerevisiae isolates from a variety of ecological niches to create 225 unique mitochondrial-nuclear genotypes. Analysis of phenotypic profiles confirmed that environmentally-sensitive interactions between mitochondrial and nuclear genotype contributed to growth differences. Exchanges of mtDNAs between strains of the same or different clades were just as likely to demonstrate mitonuclear epistasis although epistatic effect sizes increased with genetic distances. Strains with their original mtDNAs were more fit than strains with synthetic mitonuclear combinations when grown in media that resembled isolation habitats. CONCLUSIONS This study shows that natural variation in mitonuclear interactions contributes to fitness landscapes. Multiple examples of coadapted mitochondrial-nuclear genotypes suggest that selection for mitonuclear interactions may play a role in helping yeasts adapt to novel environments and promote coevolution.
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Affiliation(s)
- Tuc H M Nguyen
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA
| | - Sargunvir Sondhi
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA
| | - Andrew Ziesel
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA
| | - Swati Paliwal
- Department of Bioscience and Biotechnology, Banasthali Vidyapith, Rajasthan, India
| | - Heather L Fiumera
- Department of Biological Sciences, Binghamton University, Binghamton, NY, USA.
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24
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Matha AR, Lin X. Current Perspectives on Uniparental Mitochondrial Inheritance in Cryptococcus neoformans. Pathogens 2020; 9:pathogens9090743. [PMID: 32927641 PMCID: PMC7559238 DOI: 10.3390/pathogens9090743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/04/2020] [Accepted: 09/08/2020] [Indexed: 12/18/2022] Open
Abstract
The mitochondrion is a vital organelle in most eukaryotic cells. It contains its own DNA which differs from nuclear DNA, since it is often inherited from only one parent during sexual reproduction. In anisogamous mammals, this is largely due to the fact that the oocyte has over 1000 times more copies of mitochondrial DNA than the sperm. However, in the isogamous fungus Cryptococcus neoformans, uniparental mitochondrial inheritance (UMI) still occurs during sexual reproduction. It is proposed that UMI might have evolved in the last common ancestor of eukaryotes. Thus, understanding the fundamental process of UMI in lower eukaryotes may give insights into how the process might have evolved in eukaryotic ancestors. In this review, we discuss the current knowledge regarding the cellular features as well as the molecular underpinnings of UMI in Cryptococcus during the mating process, and open questions that need to be answered to solve the mystery of UMI in this eukaryotic microbe.
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25
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Discordant evolution of mitochondrial and nuclear yeast genomes at population level. BMC Biol 2020; 18:49. [PMID: 32393264 PMCID: PMC7216626 DOI: 10.1186/s12915-020-00786-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 04/22/2020] [Indexed: 12/31/2022] Open
Abstract
Background Mitochondria are essential organelles partially regulated by their own genomes. The mitochondrial genome maintenance and inheritance differ from the nuclear genome, potentially uncoupling their evolutionary trajectories. Here, we analysed mitochondrial sequences obtained from the 1011 Saccharomyces cerevisiae strain collection and identified pronounced differences with their nuclear genome counterparts. Results In contrast with pre-whole genome duplication fungal species, S. cerevisiae mitochondrial genomes show higher genetic diversity compared to the nuclear genomes. Strikingly, mitochondrial genomes appear to be highly admixed, resulting in a complex interconnected phylogeny with a weak grouping of isolates, whereas interspecies introgressions are very rare. Complete genome assemblies revealed that structural rearrangements are nearly absent with rare inversions detected. We tracked intron variation in COX1 and COB to infer gain and loss events throughout the species evolutionary history. Mitochondrial genome copy number is connected with the nuclear genome and linearly scale up with ploidy. We observed rare cases of naturally occurring mitochondrial DNA loss, petite, with a subset of them that do not suffer the expected growth defect in fermentable rich media. Conclusions Overall, our results illustrate how differences in the biology of two genomes coexisting in the same cells can lead to discordant evolutionary histories.
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