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Ni Y, Gao X. Uncovering the role of mitochondrial genome in pathogenicity and drug resistance in pathogenic fungi. Front Cell Infect Microbiol 2025; 15:1576485. [PMID: 40308969 PMCID: PMC12040666 DOI: 10.3389/fcimb.2025.1576485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2025] [Accepted: 03/28/2025] [Indexed: 05/02/2025] Open
Abstract
Fungal infections are becoming more prevalent globally, particularly affecting immunocompromised populations, such as people living with HIV, organ transplant recipients and those on immunomodulatory therapy. Globally, approximately 6.55 million people are affected by invasive fungal infections annually, leading to serious health consequences and death. Mitochondria are membrane-bound organelles found in almost all eukaryotic cells and play an important role in cellular metabolism and energy production, including pathogenic fungi. These organelles possess their own genome, the mitochondrial genome, which is usually circular and encodes proteins essential for energy production. Variation and evolutionary adaptation within and between species' mitochondrial genomes can affect mitochondrial function, and consequently cellular energy production and metabolic activity, which may contribute to pathogenicity and drug resistance in certain fungal species. This review explores the link between the mitochondrial genome and mechanisms of fungal pathogenicity and drug resistance, with a particular focus on Cryptococcus neoformans and Candida albicans. These insights deepen our understanding of fungal biology and may provide new avenues for developing innovative therapeutic strategies.
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Affiliation(s)
- Yue Ni
- College of Life and Health Sciences, Northeastern University, Shenyang, Liaoning, China
| | - Xindi Gao
- Department of Emergency, Xinqiao Hospital, Army Medical University, Chongqing, China
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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: 7] [Impact Index Per Article: 7.0] [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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Sillamaa S, Piljukov VJ, Vaask I, Sedman T, Jõers P, Sedman J. UvrD-like helicase Hmi1 Has an ATP independent role in yeast mitochondrial DNA maintenance. DNA Repair (Amst) 2023; 132:103582. [PMID: 37839213 DOI: 10.1016/j.dnarep.2023.103582] [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: 07/07/2023] [Revised: 09/28/2023] [Accepted: 10/03/2023] [Indexed: 10/17/2023]
Abstract
Hmi1 is a UvrD-like DNA helicase required for the maintenance of the yeast Saccharomyces cerevisiae mitochondrial DNA (mtDNA). Deletion of the HMI1 ORF leads to the formation of respiration-deficient petite mutants, which either contain a short fragment of mtDNA arranged in tandem repeats or lack mtDNA completely. Here we characterize point mutants of the helicase designed to target the ATPase or ssDNA binding activity and show that these mutations do not separately lead to complete loss of the Hmi1 function. The mutant strains support ATP production via oxidative phosphorylation and enable us to directly analyze the impact of both activities on the stability of wild-type mtDNA in this petite-positive yeast. Our data reveal that Hmi1 mutants affecting ssDNA binding display a stronger defect in the maintenance of mtDNA compared to the mutants of ATP binding/hydrolysis. Hmi1 mutants impaired in ssDNA binding demonstrate sensitivity to UV irradiation and lower levels of Cox2 encoded by the mitochondrial genome. This suggests a complex and multifarious role for Hmi1 in mtDNA maintenance-linked transactions, some of which do not require the ATP-dependent helicase activity.
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Affiliation(s)
- Sirelin Sillamaa
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Vlad-Julian Piljukov
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Iris Vaask
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Tiina Sedman
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Priit Jõers
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Juhan Sedman
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia.
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Tarrés-Solé A, Battistini F, Gerhold JM, Piétrement O, Martínez-García B, Ruiz-López E, Lyonnais S, Bernadó P, Roca J, Orozco M, Le Cam E, Sedman J, Solà M. Structural analysis of the Candida albicans mitochondrial DNA maintenance factor Gcf1p reveals a dynamic DNA-bridging mechanism. Nucleic Acids Res 2023; 51:5864-5882. [PMID: 37207342 PMCID: PMC10287934 DOI: 10.1093/nar/gkad397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 04/01/2023] [Accepted: 05/03/2023] [Indexed: 05/21/2023] Open
Abstract
The compaction of mitochondrial DNA (mtDNA) is regulated by architectural HMG-box proteins whose limited cross-species similarity suggests diverse underlying mechanisms. Viability of Candida albicans, a human antibiotic-resistant mucosal pathogen, is compromised by altering mtDNA regulators. Among them, there is the mtDNA maintenance factor Gcf1p, which differs in sequence and structure from its human and Saccharomyces cerevisiae counterparts, TFAM and Abf2p. Our crystallographic, biophysical, biochemical and computational analysis showed that Gcf1p forms dynamic protein/DNA multimers by a combined action of an N-terminal unstructured tail and a long helix. Furthermore, an HMG-box domain canonically binds the minor groove and dramatically bends the DNA while, unprecedentedly, a second HMG-box binds the major groove without imposing distortions. This architectural protein thus uses its multiple domains to bridge co-aligned DNA segments without altering the DNA topology, revealing a new mechanism of mtDNA condensation.
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Affiliation(s)
- Aleix Tarrés-Solé
- Structural MitoLab, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona Science Park, Barcelona 08028, Spain
| | - Federica Battistini
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain
- Department of Biochemistry, University of Barcelona, Barcelona 08028, Spain
| | - Joachim M Gerhold
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 51010, Estonia
| | - Olivier Piétrement
- Genome Integrity and Cancer UMR 9019 CNRS, Université Paris Saclay, Gustave Roussy Campus, 114 rue Edouard Vaillant 94805VillejuifCedex, France
| | | | - Elena Ruiz-López
- Structural MitoLab, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona Science Park, Barcelona 08028, Spain
| | - Sébastien Lyonnais
- Structural MitoLab, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona Science Park, Barcelona 08028, Spain
| | - Pau Bernadó
- Centre de Biologie Structurale (CBS), Inserm, CNRS and Université de Montpellier, France, Sébastien Lyonnais, UAR 3725 CNRS, Université de Montpellier, 34000 Montpellier, France
| | - Joaquim Roca
- Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona 08028, Spain
| | - Modesto Orozco
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain
- Department of Biochemistry, University of Barcelona, Barcelona 08028, Spain
| | - Eric Le Cam
- Genome Integrity and Cancer UMR 9019 CNRS, Université Paris Saclay, Gustave Roussy Campus, 114 rue Edouard Vaillant 94805VillejuifCedex, France
| | - Juhan Sedman
- Institute of Molecular and Cell Biology, University of Tartu, Tartu 51010, Estonia
| | - Maria Solà
- Structural MitoLab, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona Science Park, Barcelona 08028, Spain
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Harman A, Barth C. The Dictyostelium discoideum homologue of Twinkle, Twm1, is a mitochondrial DNA helicase, an active primase and promotes mitochondrial DNA replication. BMC Mol Biol 2018; 19:12. [PMID: 30563453 PMCID: PMC6299598 DOI: 10.1186/s12867-018-0114-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 11/07/2018] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND DNA replication requires contributions from various proteins, such as DNA helicases; in mitochondria Twinkle is important for maintaining and replicating mitochondrial DNA. Twinkle helicases are predicted to also possess primase activity, as has been shown in plants; however this activity appears to have been lost in metazoans. Given this, the study of Twinkle in other organisms is required to better understand the evolution of this family and the roles it performs within mitochondria. RESULTS Here we describe the characterization of a Twinkle homologue, Twm1, in the amoeba Dictyostelium discoideum, a model organism for mitochondrial genetics and disease. We show that Twm1 is important for mitochondrial function as it maintains mitochondrial DNA copy number in vivo. Twm1 is a helicase which unwinds DNA resembling open forks, although it can act upon substrates with a single 3' overhang, albeit less efficiently. Furthermore, unlike human Twinkle, Twm1 has primase activity in vitro. Finally, using a novel in bacterio approach, we demonstrated that Twm1 promotes DNA replication. CONCLUSIONS We conclude that Twm1 is a replicative mitochondrial DNA helicase which is capable of priming DNA for replication. Our results also suggest that non-metazoan Twinkle could function in the initiation of mitochondrial DNA replication. While further work is required, this study has illuminated several alternative processes of mitochondrial DNA maintenance which might also be performed by the Twinkle family of helicases.
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Affiliation(s)
- Ashley Harman
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC Australia
- Present Address: Cell Biology Unit, Children’s Medical Research Institute, University of Sydney, Westmead, NSW Australia
| | - Christian Barth
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, VIC Australia
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Dong Y, Zhang D, Yu Q, Zhao Q, Xiao C, Zhang K, Jia C, Chen S, Zhang B, Zhang B, Li M. Loss of Ssq1 leads to mitochondrial dysfunction, activation of autophagy and cell cycle arrest due to iron overload triggered by mitochondrial iron-sulfur cluster assembly defects in Candida albicans. Int J Biochem Cell Biol 2017; 85:44-55. [PMID: 28163187 DOI: 10.1016/j.biocel.2017.01.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 12/30/2016] [Accepted: 01/29/2017] [Indexed: 01/10/2023]
Abstract
Iron-sulfur clusters perform essential functions in enzymatic catalysis and homeostatic regulation. Here we for the first time identified Ssq1 as an essential component for iron-sulfur cluster assembly in Candida albicans. Ssq1 played an important role in cell growth. Shutting off SSQ1 led to accumulation of intracellular iron, especially in mitochondria, and disorder of intracellular iron regulation. In tetO-SSQ1, iron overloading triggered the oxidative damage of mitochondrial function. Surprisingly, disruption of SSQ1 activated autophagic pathway. The mitochondrial dysfunction was further aggravated when CCZ1 (which is essential for autophagy) and SSQ1 was simultaneously deleted, suggesting that autophagy played a critical role in maintenance of mitochondrial function in tetO-SSQ1. In addition, double deletion of SSQ1 and CCZ1 further elevated cellular iron levels in comparison with tetO-SSQ1, indicating that autophagy participated in maintenance of iron homeostasis. Furthermore, we found that loss of SSQ1 led to increasing protein expression of Rnr1 and redistribution of Rnr2 from the nucleus to cytoplasm, and further resulted in cell cycle arrest. The results implied that cell cycle arrest was caused by activating the checkpoint pathway because of impairing the iron-sulfur cluster assembly in tetO-SSQ1. Shutting off SSQ1 led to a significant defect in filamentous development. Interestingly, the tetO-SSQ1ccz1Δ/Δ growth was inhibited on hyphae-inducing solid media. Both tetO-SSQ1 and tetO-SSQ1ccz1Δ/Δ exhibited extremely attenuated virulence, indicating that Ssq1 might provide a promising target for antifungal drugs development. In summary, our findings provide new insights into the understanding of iron-sulfur cluster assembly-related gene in C. albicans.
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Affiliation(s)
- Yijie Dong
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China; The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, PR China
| | - Dan Zhang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Qilin Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Qiang Zhao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Chenpeng Xiao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Kai Zhang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Chang Jia
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Sijia Chen
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Bing Zhang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China
| | - Biao Zhang
- Tianjin University of Traditional Chinese Medicine, Tianjin, PR China
| | - Mingchun Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China.
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Kolondra A, Labedzka-Dmoch K, Wenda JM, Drzewicka K, Golik P. The transcriptome of Candida albicans mitochondria and the evolution of organellar transcription units in yeasts. BMC Genomics 2015; 16:827. [PMID: 26487099 PMCID: PMC4618339 DOI: 10.1186/s12864-015-2078-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 10/13/2015] [Indexed: 02/06/2023] Open
Abstract
Background Yeasts show remarkable variation in the organization of their mitochondrial genomes, yet there is little experimental data on organellar gene expression outside few model species. Candida albicans is interesting as a human pathogen, and as a representative of a clade that is distant from the model yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe. Unlike them, it encodes seven Complex I subunits in its mtDNA. No experimental data regarding organellar expression were available prior to this study. Methods We used high-throughput RNA sequencing and traditional RNA biology techniques to study the mitochondrial transcriptome of C. albicans strains BWP17 and SN148. Results The 14 protein-coding genes, two ribosomal RNA genes, and 24 tRNA genes are expressed as eight primary polycistronic transcription units. We also found transcriptional activity in the noncoding regions, and antisense transcripts that could be a part of a regulatory mechanism. The promoter sequence is a variant of the nonanucleotide identified in other yeast mtDNAs, but some of the active promoters show significant departures from the consensus. The primary transcripts are processed by a tRNA punctuation mechanism into the monocistronic and bicistronic mature RNAs. The steady state levels of various mature transcripts exhibit large differences that are a result of posttranscriptional regulation. Transcriptome analysis allowed to precisely annotate the positions of introns in the RNL (2), COB (2) and COX1 (4) genes, as well as to refine the annotation of tRNAs and rRNAs. Comparative study of the mitochondrial genome organization in various Candida species indicates that they undergo shuffling in blocks usually containing 2–3 genes, and that their arrangement in primary transcripts is not conserved. tRNA genes with their associated promoters, as well as GC-rich sequence elements play an important role in these evolutionary events. Conclusions The main evolutionary force shaping the mitochondrial genomes of yeasts is the frequent recombination, constantly breaking apart and joining genes into novel primary transcription units. The mitochondrial transcription units are constantly rearranged in evolution shaping the features of gene expression, such as the presence of secondary promoter sites that are inactive, or act as “booster” promoters, simplified transcriptional regulation and reliance on posttranscriptional mechanisms. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2078-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adam Kolondra
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland.
| | - Karolina Labedzka-Dmoch
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland.
| | - Joanna M Wenda
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland.
| | - Katarzyna Drzewicka
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland.
| | - Pawel Golik
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland. .,Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106, Warsaw, Poland.
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Gerhold JM, Sedman T, Visacka K, Slezakova J, Tomaska L, Nosek J, Sedman J. Replication intermediates of the linear mitochondrial DNA of Candida parapsilosis suggest a common recombination based mechanism for yeast mitochondria. J Biol Chem 2014; 289:22659-22670. [PMID: 24951592 DOI: 10.1074/jbc.m114.552828] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Variation in the topology of mitochondrial DNA (mtDNA) in eukaryotes evokes the question if differently structured DNAs are replicated by a common mechanism. RNA-primed DNA synthesis has been established as a mechanism for replicating the circular animal/mammalian mtDNA. In yeasts, circular mtDNA molecules were assumed to be templates for rolling circle DNA-replication. We recently showed that in Candida albicans, which has circular mapping mtDNA, recombination driven replication is a major mechanism for replicating a complex branched mtDNA network. Careful analyses of C. albicans-mtDNA did not reveal detectable amounts of circular DNA molecules. In the present study we addressed the question of how the unit sized linear mtDNA of Candida parapsilosis terminating at both ends with arrays of tandem repeats (mitochondrial telomeres) is replicated. Originally, we expected to find replication intermediates diagnostic of canonical bi-directional replication initiation at the centrally located bi-directional promoter region. However, we found that the linear mtDNA of Candida parapsilosis also employs recombination for replication initiation. The most striking findings were that the mitochondrial telomeres appear to be hot spots for recombination driven replication, and that stable RNA:DNA hybrids, with a potential role in mtDNA replication, are also present in the mtDNA preparations.
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Affiliation(s)
- Joachim M Gerhold
- Department of Biochemistry, Institute of Molecular and Cell Biology, University of Tartu, Riia 23c, 51014 Tartu, Estonia and.
| | - Tiina Sedman
- Department of Biochemistry, Institute of Molecular and Cell Biology, University of Tartu, Riia 23c, 51014 Tartu, Estonia and
| | - Katarina Visacka
- Department of Genetics, Faculty of Natural Sciences, Comenius University, Mlynská dolina B-1, and
| | - Judita Slezakova
- Department of Genetics, Faculty of Natural Sciences, Comenius University, Mlynská dolina B-1, and
| | - Lubomir Tomaska
- Department of Genetics, Faculty of Natural Sciences, Comenius University, Mlynská dolina B-1, and
| | - Jozef Nosek
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Mlynská dolina CH-1, 842 15 Bratislava, Slovak Republic
| | - Juhan Sedman
- Department of Biochemistry, Institute of Molecular and Cell Biology, University of Tartu, Riia 23c, 51014 Tartu, Estonia and
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Xu N, Dong Y, Cheng X, Yu Q, Qian K, Mao J, Jia C, Ding X, Zhang B, Chen Y, Zhang B, Xing L, Li M. Cellular iron homeostasis mediated by the Mrs4–Ccc1–Smf3 pathway is essential for mitochondrial function, morphogenesis and virulence in Candida albicans. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:629-39. [DOI: 10.1016/j.bbamcr.2013.12.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 12/11/2013] [Accepted: 12/13/2013] [Indexed: 11/29/2022]
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Mitochondrial sorting and assembly machinery subunit Sam37 in Candida albicans: insight into the roles of mitochondria in fitness, cell wall integrity, and virulence. EUKARYOTIC CELL 2012; 11:532-44. [PMID: 22286093 DOI: 10.1128/ec.05292-11] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recent studies indicate that mitochondrial functions impinge on cell wall integrity, drug tolerance, and virulence of human fungal pathogens. However, the mechanistic aspects of these processes are poorly understood. We focused on the mitochondrial outer membrane SAM (Sorting and Assembly Machinery) complex subunit Sam37 in Candida albicans. Inactivation of SAM37 in C. albicans leads to a large reduction in fitness, a phenotype not conserved with the model yeast Saccharomyces cerevisiae. Our data indicate that slow growth of the sam37ΔΔ mutant results from mitochondrial DNA loss, a new function for Sam37 in C. albicans, and from reduced activity of the essential SAM complex subunit Sam35. The sam37ΔΔ mutant was hypersensitive to drugs that target the cell wall and displayed altered cell wall structure, supporting a role for Sam37 in cell wall integrity in C. albicans. The sensitivity of the mutant to membrane-targeting antifungals was not significantly altered. The sam37ΔΔ mutant was avirulent in the mouse model, and bioinformatics showed that the fungal Sam37 proteins are distant from their animal counterparts and could thus represent potential drug targets. Our study provides the first direct evidence for a link between mitochondrial function and cell wall integrity in C. albicans and is further relevant for understanding mitochondrial function in fitness, antifungal drug tolerance, and virulence of this major pathogen. Beyond the relevance to fungal pathogenesis, this work also provides new insight into the mitochondrial and cellular roles of the SAM complex in fungi.
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Gerhold JM, Aun A, Sedman T, Jõers P, Sedman J. Strand Invasion Structures in the Inverted Repeat of Candida albicans Mitochondrial DNA Reveal a Role for Homologous Recombination in Replication. Mol Cell 2010; 39:851-61. [DOI: 10.1016/j.molcel.2010.09.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 03/18/2010] [Accepted: 07/28/2010] [Indexed: 11/16/2022]
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Bambach A, Fernandes MP, Ghosh A, Kruppa M, Alex D, Li D, Fonzi WA, Chauhan N, Sun N, Agrellos OA, Vercesi AE, Rolfes RJ, Calderone R. Goa1p of Candida albicans localizes to the mitochondria during stress and is required for mitochondrial function and virulence. EUKARYOTIC CELL 2009; 8:1706-20. [PMID: 19717740 PMCID: PMC2772395 DOI: 10.1128/ec.00066-09] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Accepted: 08/18/2009] [Indexed: 11/20/2022]
Abstract
Using a Tn7 transposon library of Candida albicans, we have identified a mutant that exhibited sensitivity in drop plate assays to oxidants such as menadione and hydrogen peroxide. To verify the role of the mutated gene in stress adaptation, null mutants were constructed and phenotypically characterized. Because of its apparent functions in growth and oxidant adaptation, we have named the gene GOA1. Goa1p appears to be unique to the CTG subclade of the Saccharomycotina, including C. albicans. Mutants of C. albicans lacking goa1 (strain GOA31) were more sensitive to 6 mM H(2)O(2) and 0.125 mM menadione than the wild type (wt) or a gene-reconstituted (GOA32) strain. The sensitivity to oxidants correlated with reduced survival of the GOA31 mutant in human neutrophils and avirulence compared to control strains. Other phenotypes of GOA31 include reduced growth and filamentation in 10% serum, Spider, and SLAD agar media and an inability to form chlamydospores. Since Goa1p has an N-terminal mitochondrion localization site, we also show that green fluorescent protein-tagged Goa1p shows a mitochondrionlike distribution during oxidant or osmotic stress. Further, the inability of GOA31 to grow in medium containing lactate, ethanol, or glycerol as the sole carbon source indicates that the mitochondria are defective in the mutant. To determine how Goa1p contributes to mitochondrial function, we compared the wt, GOA32, and GOA31 strains for mitochondrial electrical membrane potential, respiration, and oxidative phosphorylation. We now show that GOA31, but not the wt or GOA32, had decreased respiration and mitochondrial membrane potential such that mutant cells are unable to drive oxidative phosphorylation. This is the first report in C. albicans of a respiratory defect caused by a loss of mitochondrial membrane potential.
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Affiliation(s)
- Adrienne Bambach
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, Departamento de Patologia Clínica, Universidade Estadual de Campinas, Campinas, Brazil, Department of Biology, Georgetown University, Washington, DC, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Mariana P. Fernandes
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, Departamento de Patologia Clínica, Universidade Estadual de Campinas, Campinas, Brazil, Department of Biology, Georgetown University, Washington, DC, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Anup Ghosh
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, Departamento de Patologia Clínica, Universidade Estadual de Campinas, Campinas, Brazil, Department of Biology, Georgetown University, Washington, DC, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Michael Kruppa
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, Departamento de Patologia Clínica, Universidade Estadual de Campinas, Campinas, Brazil, Department of Biology, Georgetown University, Washington, DC, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Deepu Alex
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, Departamento de Patologia Clínica, Universidade Estadual de Campinas, Campinas, Brazil, Department of Biology, Georgetown University, Washington, DC, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Dongmei Li
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, Departamento de Patologia Clínica, Universidade Estadual de Campinas, Campinas, Brazil, Department of Biology, Georgetown University, Washington, DC, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - William A. Fonzi
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, Departamento de Patologia Clínica, Universidade Estadual de Campinas, Campinas, Brazil, Department of Biology, Georgetown University, Washington, DC, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Neeraj Chauhan
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, Departamento de Patologia Clínica, Universidade Estadual de Campinas, Campinas, Brazil, Department of Biology, Georgetown University, Washington, DC, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nuo Sun
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, Departamento de Patologia Clínica, Universidade Estadual de Campinas, Campinas, Brazil, Department of Biology, Georgetown University, Washington, DC, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Orlando A. Agrellos
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, Departamento de Patologia Clínica, Universidade Estadual de Campinas, Campinas, Brazil, Department of Biology, Georgetown University, Washington, DC, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Anibal E. Vercesi
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, Departamento de Patologia Clínica, Universidade Estadual de Campinas, Campinas, Brazil, Department of Biology, Georgetown University, Washington, DC, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ronda J. Rolfes
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, Departamento de Patologia Clínica, Universidade Estadual de Campinas, Campinas, Brazil, Department of Biology, Georgetown University, Washington, DC, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Richard Calderone
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, Departamento de Patologia Clínica, Universidade Estadual de Campinas, Campinas, Brazil, Department of Biology, Georgetown University, Washington, DC, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Holt IJ, He J, Mao CC, Boyd-Kirkup JD, Martinsson P, Sembongi H, Reyes A, Spelbrink JN. Mammalian mitochondrial nucleoids: Organizing an independently minded genome. Mitochondrion 2007; 7:311-21. [PMID: 17698423 DOI: 10.1016/j.mito.2007.06.004] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 05/31/2007] [Accepted: 06/25/2007] [Indexed: 11/23/2022]
Abstract
Mitochondrial DNA is arranged in nucleoprotein complexes, or nucleoids. Nucleoid proteins include not only factors involved in replication and transcription but also structural proteins required for mitochondrial DNA maintenance. Although several nucleoid proteins have been identified and characterized in yeast over the course of the past decade, little was known of mammalian mitochondrial nucleoids until recently. Two publications in the past year have expanded considerably the pool of putative mammalian mitochondrial nucleoid proteins; and analysis of one of the candidates, ATAD3p, suggests that mitochondrial nucleoid formation and division are orchestrated, not random, events.
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Affiliation(s)
- Ian J Holt
- MRC-Dunn Human Nutrition Unit, Wellcome Trust-MRC Building, Hills Road, Cambridge CB2 OXY, UK.
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14
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John Wiley & Sons, Ltd.. Current awareness on yeast. Yeast 2007. [DOI: 10.1002/yea.1453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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