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Dubie JJ, Katju V, Bergthorsson U. Dissecting the sequential evolution of a selfish mitochondrial genome in Caenorhabditis elegans. Heredity (Edinb) 2024; 133:186-197. [PMID: 38969772 PMCID: PMC11349875 DOI: 10.1038/s41437-024-00704-2] [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: 02/01/2024] [Revised: 06/24/2024] [Accepted: 06/25/2024] [Indexed: 07/07/2024] Open
Abstract
Mitochondrial genomes exist in a nested hierarchy of populations where mitochondrial variants are subject to genetic drift and selection at each level of organization, sometimes engendering conflict between different levels of selection, and between the nuclear and mitochondrial genomes. Deletion mutants in the Caenorhabditis elegans mitochondrial genome can reach high intracellular frequencies despite strongly detrimental effects on fitness. During a mutation accumulation (MA) experiment in C. elegans, a 499 bp deletion in ctb-1 rose to 90% frequency within cells while significantly reducing fitness. During the experiment, the deletion-bearing mtDNA acquired three additional mutations in nd5, namely two single insertion frameshift mutations in a homopolymeric run, and a base substitution. Despite an additional fitness cost of these secondary mutations, all deletion-bearing molecules contained the nd5 mutations at the termination of the MA experiment. The presence of mutant mtDNA was associated with increased mtDNA copy-number. Variation in mtDNA copy-number was greater in the MA lines than in a wildtype nuclear background, including a severe reduction in copy-number at one generational timepoint. Evolutionary replay experiments using different generations of the MA experiment as starting points suggests that two of the secondary mutations contribute to the proliferation of the original ctb-1 deletion by unknown mechanisms.
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Affiliation(s)
- Joseph J Dubie
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA
- Department of Integrative Biology, University of Texas, Austin, TX, USA
| | - Vaishali Katju
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA.
- Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 752 36, Uppsala, Sweden.
| | - Ulfar Bergthorsson
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA.
- Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 752 36, Uppsala, Sweden.
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Chiang ACY, Ježek J, Mu P, Di Y, Klucnika A, Jabůrek M, Ježek P, Ma H. Two mitochondrial DNA polymorphisms modulate cardiolipin binding and lead to synthetic lethality. Nat Commun 2024; 15:611. [PMID: 38242869 PMCID: PMC10799063 DOI: 10.1038/s41467-024-44964-2] [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: 06/08/2023] [Accepted: 01/10/2024] [Indexed: 01/21/2024] Open
Abstract
Genetic screens have been used extensively to probe interactions between nuclear genes and their impact on phenotypes. Probing interactions between mitochondrial genes and their phenotypic outcome, however, has not been possible due to a lack of tools to map the responsible polymorphisms. Here, using a toolkit we previously established in Drosophila, we isolate over 300 recombinant mitochondrial genomes and map a naturally occurring polymorphism at the cytochrome c oxidase III residue 109 (CoIII109) that fully rescues the lethality and other defects associated with a point mutation in cytochrome c oxidase I (CoIT300I). Through lipidomics profiling, biochemical assays and phenotypic analyses, we show that the CoIII109 polymorphism modulates cardiolipin binding to prevent complex IV instability caused by the CoIT300I mutation. This study demonstrates the feasibility of genetic interaction screens in animal mitochondrial DNA. It unwraps the complex intra-genomic interplays underlying disorders linked to mitochondrial DNA and how they influence disease expression.
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Affiliation(s)
- Ason C Y Chiang
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
- Wellcome/Cancer Research UK Gurdon Institute, Tennis Court Road, Cambridge, CB2 1QN, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Jan Ježek
- Wellcome/Cancer Research UK Gurdon Institute, Tennis Court Road, Cambridge, CB2 1QN, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
- University College London Queen Square Institute of Neurology, Royal Free Hospital, Rowland Hill Street, London, NW3 2PF, UK
| | - Peiqiang Mu
- Wellcome/Cancer Research UK Gurdon Institute, Tennis Court Road, Cambridge, CB2 1QN, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, South China Agricultural University, Tianhe District, 510642, Guangzhou, Guangdong, P. R. China
| | - Ying Di
- Wellcome/Cancer Research UK Gurdon Institute, Tennis Court Road, Cambridge, CB2 1QN, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Anna Klucnika
- Wellcome/Cancer Research UK Gurdon Institute, Tennis Court Road, Cambridge, CB2 1QN, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
- Laverock Therapeutics, Stevenage Bioscience Catalyst, Gunnels Wood Road, Stevenage, SG1 2FX, UK
| | - Martin Jabůrek
- Laboratory of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Videnska 1083, 142 20, Prague, Czech Republic
| | - Petr Ježek
- Laboratory of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Videnska 1083, 142 20, Prague, Czech Republic
| | - Hansong Ma
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
- Wellcome/Cancer Research UK Gurdon Institute, Tennis Court Road, Cambridge, CB2 1QN, UK.
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK.
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3
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Sato G, Kuroda K. Overcoming the Limitations of CRISPR-Cas9 Systems in Saccharomyces cerevisiae: Off-Target Effects, Epigenome, and Mitochondrial Editing. Microorganisms 2023; 11:microorganisms11041040. [PMID: 37110464 PMCID: PMC10145089 DOI: 10.3390/microorganisms11041040] [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: 02/02/2023] [Revised: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Modification of the genome of the yeast Saccharomyces cerevisiae has great potential for application in biological research and biotechnological advancements, and the CRISPR-Cas9 system has been increasingly employed for these purposes. The CRISPR-Cas9 system enables the precise and simultaneous modification of any genomic region of the yeast to a desired sequence by altering only a 20-nucleotide sequence within the guide RNA expression constructs. However, the conventional CRISPR-Cas9 system has several limitations. In this review, we describe the methods that were developed to overcome these limitations using yeast cells. We focus on three types of developments: reducing the frequency of unintended editing to both non-target and target sequences in the genome, inducing desired changes in the epigenetic state of the target region, and challenging the expansion of the CRISPR-Cas9 system to edit genomes within intracellular organelles such as mitochondria. These developments using yeast cells to overcome the limitations of the CRISPR-Cas9 system are a key factor driving the advancement of the field of genome editing.
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Affiliation(s)
- Genki Sato
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kouichi Kuroda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
- Department of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
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Genome-wide local ancestry and evidence for mitonuclear coadaptation in African hybrid cattle populations (Bos taurus/indicus). iScience 2022; 25:104672. [PMID: 35832892 PMCID: PMC9272374 DOI: 10.1016/j.isci.2022.104672] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 05/11/2022] [Accepted: 06/21/2022] [Indexed: 11/21/2022] Open
Abstract
The phenotypic diversity of African cattle reflects adaptation to a wide range of agroecological conditions, human-mediated selection preferences, and complex patterns of admixture between the humpless Bos taurus (taurine) and humped Bos indicus (zebu) subspecies, which diverged 150-500 thousand years ago. Despite extensive admixture, all African cattle possess taurine mitochondrial haplotypes, even populations with significant zebu biparental and male uniparental nuclear ancestry. This has been interpreted as the result of human-mediated dispersal ultimately stemming from zebu bulls imported from South Asia during the last three millennia. Here, we assess whether ancestry at mitochondrially targeted nuclear genes in African admixed cattle is impacted by mitonuclear functional interactions. Using high-density SNP data, we find evidence for mitonuclear coevolution across hybrid African cattle populations with a significant increase of taurine ancestry at mitochondrially targeted nuclear genes. Our results, therefore, support the hypothesis of incompatibility between the taurine mitochondrial genome and the zebu nuclear genome.
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Elston KM, Leonard SP, Geng P, Bialik SB, Robinson E, Barrick JE. Engineering insects from the endosymbiont out. Trends Microbiol 2021; 30:79-96. [PMID: 34103228 DOI: 10.1016/j.tim.2021.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/19/2021] [Accepted: 05/11/2021] [Indexed: 01/28/2023]
Abstract
Insects are an incredibly diverse group of animals with species that benefit and harm natural ecosystems, agriculture, and human health. Many insects have consequential associations with microbes: bacterial symbionts may be embedded in different insect tissues and cell types, inherited across insect generations, and required for insect survival and reproduction. Genetically engineering insect symbionts is key to understanding and harnessing these associations. We summarize different types of insect-bacteria relationships and review methods used to genetically modify endosymbiont and gut symbiont species. Finally, we discuss recent studies that use this approach to study symbioses, manipulate insect-microbe interactions, and influence insect biology. Further progress in insect symbiont engineering promises to solve societal challenges, ranging from controlling pests to protecting pollinator health.
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Affiliation(s)
- Katherine M Elston
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Sean P Leonard
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Peng Geng
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Sarah B Bialik
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Elizabeth Robinson
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jeffrey E Barrick
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA.
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6
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Yoon YG. Transfer of Xenomitochondria Containing the Entire Mouse Mitochondrial Genome into a Genetically Modified Yeast Expressing Mitochondrial Transcription Factor A. J Microbiol Biotechnol 2020; 30:1290-1296. [PMID: 32627757 PMCID: PMC9728338 DOI: 10.4014/jmb.2004.04033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/16/2020] [Accepted: 07/03/2020] [Indexed: 12/15/2022]
Abstract
Recently, it was reported that entire mammalian mtDNA genomes could be transplanted into the mitochondrial networks of yeast, where they were accurately and stably maintained without rearrangement as intact genomes. Here, it was found that engineered mtDNA genomes could be readily transferred to and steadily maintained in the mitochondria of genetically modified yeast expressing the mouse mitochondrial transcription factor A (Tfam), one of the mitochondrial nucleoid proteins. The transferred mtDNA genomes were stably retained in the Tfam-expressing yeast cells for many generations. These results indicated that the engineered mouse mtDNA genomes introduced in yeast mitochondria could be relocated into the mitochondria of other cells and that the transferred genomes could be maintained within a mitochondrial environment that is highly amenable to mimicry of the biological conditions in mammalian mitochondria.
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Affiliation(s)
- Young Geol Yoon
- Department of Biomedical Science, Jungwon University, Goesan-gun, Chungbuk 28024, Republic of Korea,Corresponding author Phone: +82-43-830-8681 Fax: +82-43-830-8579 E-mail:
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7
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Introduction of a leaky stop codon as molecular tool in Chlamydomonas reinhardtii. PLoS One 2020; 15:e0237405. [PMID: 32817702 PMCID: PMC7440625 DOI: 10.1371/journal.pone.0237405] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/24/2020] [Indexed: 02/07/2023] Open
Abstract
Expression of proteins in the chloroplast or mitochondria of the model green alga Chlamydomonas reinhardtii can be achieved by directly inserting transgenes into organellar genomes, or through nuclear expression and post-translational import. A number of tools have been developed in the literature for achieving high expression levels from the nuclear genome despite messy genomic integration and widespread silencing of transgenes. Here, recent advances in the field are combined and two systems of bicistronic expression, based on ribosome reinitiation or ribosomal skip induced by a viral 2A sequence, are compared side-by-side. Further, the small subunit of Rubisco (RBCS) was developed as a functional nuclear reporter for successful chloroplast import and restoration of photosynthesis: To be able to combine RBCS with a Venus fluorescent reporter without compromising photosynthetic activity, a leaky stop codon is introduced as a novel molecular tool that allows the simultaneous expression of functional and fluorescently tagged versions of the protein from a single construct.
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Cappa R, de Campos C, Maxwell AP, McKnight AJ. "Mitochondrial Toolbox" - A Review of Online Resources to Explore Mitochondrial Genomics. Front Genet 2020; 11:439. [PMID: 32457801 PMCID: PMC7225359 DOI: 10.3389/fgene.2020.00439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 04/09/2020] [Indexed: 12/30/2022] Open
Abstract
Mitochondria play a significant role in many biological systems. There is emerging evidence that differences in the mitochondrial genome may contribute to multiple common diseases, leading to an increasing number of studies exploring mitochondrial genomics. There is often a large amount of complex data generated (for example via next generation sequencing), which requires optimised bioinformatics tools to efficiently and effectively generate robust outcomes from these large datasets. Twenty-four online resources dedicated to mitochondrial genomics were reviewed. This 'mitochondrial toolbox' summary resource will enable researchers to rapidly identify the resource(s) most suitable for their needs. These resources fulfil a variety of functions, with some being highly specialised. No single tool will provide all users with the resources they require; therefore, the most suitable tool will vary between users depending on the nature of the work they aim to carry out. Genetics resources are well established for phylogeny and DNA sequence changes, but further epigenetic and gene expression resources need to be developed for mitochondrial genomics.
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Affiliation(s)
- Ruaidhri Cappa
- Centre for Public Health, Institute of Clinical Sciences B, Queen's University Belfast, Royal Victoria Hospital, Belfast, United Kingdom
| | - Cassio de Campos
- School of Electronics, Electrical Engineering and Computer Science, Queen's University Belfast, Belfast, United Kingdom
| | - Alexander P Maxwell
- Centre for Public Health, Institute of Clinical Sciences B, Queen's University Belfast, Royal Victoria Hospital, Belfast, United Kingdom
| | - Amy J McKnight
- Centre for Public Health, Institute of Clinical Sciences B, Queen's University Belfast, Royal Victoria Hospital, Belfast, United Kingdom
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Song N, Geng Y, Li X. The Mitochondrial Genome of the Phytopathogenic Fungus Bipolaris sorokiniana and the Utility of Mitochondrial Genome to Infer Phylogeny of Dothideomycetes. Front Microbiol 2020; 11:863. [PMID: 32457727 PMCID: PMC7225605 DOI: 10.3389/fmicb.2020.00863] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 04/09/2020] [Indexed: 12/01/2022] Open
Abstract
A number of species in Bipolaris are important plant pathogens. Due to a limited number of synapomorphic characters, it is difficult to perform species identification and to estimate phylogeny of Bipolaris based solely on morphology. In this study, we sequenced the complete mitochondrial genome of Bipolaris sorokiniana, and presented the detailed annotation of the genome. The B. sorokiniana mitochondrial genome is 137,775 bp long, and contains two ribosomal RNA genes, 12 core protein-coding genes, 38 tRNA genes. In addition, two ribosomal protein genes (rps3 gene and rps5 gene) and the fungal mitochondrial RNase P gene (rnpB) are identified. The large genome size is mostly determined by the presence of numerous intronic and intergenic regions. A total of 28 introns are inserted in eight core protein-coding genes. Together with the published mitochondrial genome sequences, we conducted a preliminary phylogenetic inference of Dothideomycetes under various datasets and substitution models. The monophyly of Capnodiales, Botryosphaeriales and Pleosporales are consistently supported in all analyses. The Venturiaceae forms an independent lineage, with a distant phylogenetic relationship to Pleosporales. At the family level, the Mycosphaerellaceae, Botryosphaeriaceae. Phaeosphaeriaceae, and Pleosporaceae are recognized in the majority of trees.
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Affiliation(s)
- Nan Song
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Yuehua Geng
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
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Ghiselli F, Milani L. Linking the mitochondrial genotype to phenotype: a complex endeavour. Philos Trans R Soc Lond B Biol Sci 2019; 375:20190169. [PMID: 31787041 DOI: 10.1098/rstb.2019.0169] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Finding causal links between genotype and phenotype is a major issue in biology, even more in mitochondrial biology. First of all, mitochondria form complex networks, undergoing fission and fusion and we do not know how such dynamics influence the distribution of mtDNA variants across the mitochondrial network and how they affect the phenotype. Second, the non-Mendelian inheritance of mitochondrial genes can have sex-specific effects and the mechanism of mitochondrial inheritance is still poorly understood, so it is not clear how selection and/or drift act on mtDNA genetic variation in each generation. Third, we still do not know how mtDNA expression is regulated; there is growing evidence for a convoluted mechanism that includes RNA editing, mRNA stability/turnover, post-transcriptional and post-translational modifications. Fourth, mitochondrial activity differs across species as a result of several interacting processes such as drift, adaptation, genotype-by-environment interactions, mitonuclear coevolution and epistasis. This issue will cover several aspects of mitochondrial biology along the path from genotype to phenotype, and it is subdivided into four sections focusing on mitochondrial genetic variation, on the relationship among mitochondria, germ line and sex, on the role of mitochondria in adaptation and phenotypic plasticity, and on some future perspectives in mitochondrial research. This article is part of the theme issue 'Linking the mitochondrial genotype to phenotype: a complex endeavour'.
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Affiliation(s)
- Fabrizio Ghiselli
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, Bologna 40126, Italy
| | - Liliana Milani
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, Bologna 40126, Italy
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