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Dombi E, Marinaki T, Spingardi P, Millar V, Hadjichristou N, Carver J, Johnston IG, Fratter C, Poulton J. Nucleoside supplements as treatments for mitochondrial DNA depletion syndrome. Front Cell Dev Biol 2024; 12:1260496. [PMID: 38665433 PMCID: PMC11043827 DOI: 10.3389/fcell.2024.1260496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 03/11/2024] [Indexed: 04/28/2024] Open
Abstract
Introduction: In mitochondrial DNA (mtDNA) depletion syndrome (MDS), patients cannot maintain sufficient mtDNA for their energy needs. MDS presentations range from infantile encephalopathy with hepatopathy (Alpers syndrome) to adult chronic progressive external ophthalmoplegia. Most are caused by nucleotide imbalance or by defects in the mtDNA replisome. There is currently no curative treatment available. Nucleoside therapy is a promising experimental treatment for TK2 deficiency, where patients are supplemented with exogenous deoxypyrimidines. We aimed to explore the benefits of nucleoside supplementation in POLG and TWNK deficient fibroblasts. Methods: We used high-content fluorescence microscopy with software-based image analysis to assay mtDNA content and membrane potential quantitatively, using vital dyes PicoGreen and MitoTracker Red CMXRos respectively. We tested the effect of 15 combinations (A, T, G, C, AT, AC, AG, CT, CG, GT, ATC, ATG, AGC, TGC, ATGC) of deoxynucleoside supplements on mtDNA content of fibroblasts derived from four patients with MDS (POLG1, POLG2, DGUOK, TWNK) in both a replicating (10% dialysed FCS) and quiescent (0.1% dialysed FCS) state. We used qPCR to measure mtDNA content of supplemented and non-supplemented fibroblasts following mtDNA depletion using 20 µM ddC and after 14- and 21-day recovery in a quiescent state. Results: Nucleoside treatments at 200 µM that significantly increased mtDNA content also significantly reduced the number of cells remaining in culture after 7 days of treatment, as well as mitochondrial membrane potential. These toxic effects were abolished by reducing the concentration of nucleosides to 50 µM. In POLG1 and TWNK cells the combination of ATGC treatment increased mtDNA content the most after 7 days in non-replicating cells. ATGC nucleoside combination significantly increased the rate of mtDNA recovery in quiescent POLG1 cells following mtDNA depletion by ddC. Conclusion: High-content imaging enabled us to link mtDNA copy number with key read-outs linked to patient wellbeing. Elevated G increased mtDNA copy number but severely impaired fibroblast growth, potentially by inhibiting purine synthesis and/or causing replication stress. Combinations of nucleosides ATGC, T, or TC, benefited growth of cells harbouring POLG mutations. These combinations, one of which reflects a commercially available preparation, could be explored further for treatment of POLG patients.
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Affiliation(s)
- Eszter Dombi
- Nuffield Department of Women’s and Reproductive Health, University of Oxford, Oxford, United Kingdom
| | - Tony Marinaki
- Purine Research Laboratory, Department of Biochemical Sciences, Guy’s and St Thomas’ Hospitals, London, United Kingdom
| | - Paolo Spingardi
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, Medical Sciences Division, University of Oxford, Oxford, United Kingdom
| | - Val Millar
- Target Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Janet Carver
- Nuffield Department of Women’s and Reproductive Health, University of Oxford, Oxford, United Kingdom
| | - Iain G. Johnston
- Department of Mathematics, University of Bergen, Bergen, Norway
- Computational Biology Unit, University of Bergen, Bergen, Norway
| | - Carl Fratter
- Oxford Genetics Laboratories, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Joanna Poulton
- Nuffield Department of Women’s and Reproductive Health, University of Oxford, Oxford, United Kingdom
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2
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Doimo M, Chaudhari N, Abrahamsson S, L’Hôte V, Nguyen TH, Berner A, Ndi M, Abrahamsson A, Das R, Aasumets K, Goffart S, Pohjoismäki JLO, López MD, Chorell E, Wanrooij S. Enhanced mitochondrial G-quadruplex formation impedes replication fork progression leading to mtDNA loss in human cells. Nucleic Acids Res 2023; 51:7392-7408. [PMID: 37351621 PMCID: PMC10415151 DOI: 10.1093/nar/gkad535] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 06/09/2023] [Indexed: 06/24/2023] Open
Abstract
Mitochondrial DNA (mtDNA) replication stalling is considered an initial step in the formation of mtDNA deletions that associate with genetic inherited disorders and aging. However, the molecular details of how stalled replication forks lead to mtDNA deletions accumulation are still unclear. Mitochondrial DNA deletion breakpoints preferentially occur at sequence motifs predicted to form G-quadruplexes (G4s), four-stranded nucleic acid structures that can fold in guanine-rich regions. Whether mtDNA G4s form in vivo and their potential implication for mtDNA instability is still under debate. In here, we developed new tools to map G4s in the mtDNA of living cells. We engineered a G4-binding protein targeted to the mitochondrial matrix of a human cell line and established the mtG4-ChIP method, enabling the determination of mtDNA G4s under different cellular conditions. Our results are indicative of transient mtDNA G4 formation in human cells. We demonstrate that mtDNA-specific replication stalling increases formation of G4s, particularly in the major arc. Moreover, elevated levels of G4 block the progression of the mtDNA replication fork and cause mtDNA loss. We conclude that stalling of the mtDNA replisome enhances mtDNA G4 occurrence, and that G4s not resolved in a timely manner can have a negative impact on mtDNA integrity.
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Affiliation(s)
- Mara Doimo
- Department of Medical Biochemistry and Biophysics, Umeå University, 90187 Umeå, Sweden
- Department of Women and Children Health, University of Padova, 35128 Padova, Italy
| | - Namrata Chaudhari
- Department of Medical Biochemistry and Biophysics, Umeå University, 90187 Umeå, Sweden
| | - Sanna Abrahamsson
- Bioinformatics and Data Centre, Sahlgrenska Academy, University of Gothenburg, 41390 Gothenburg, Sweden
| | - Valentin L’Hôte
- Department of Medical Biochemistry and Biophysics, Umeå University, 90187 Umeå, Sweden
| | - Tran V H Nguyen
- Department of Medical Biochemistry and Biophysics, Umeå University, 90187 Umeå, Sweden
| | - Andreas Berner
- Department of Medical Biochemistry and Biophysics, Umeå University, 90187 Umeå, Sweden
| | - Mama Ndi
- Department of Medical Biochemistry and Biophysics, Umeå University, 90187 Umeå, Sweden
| | | | | | - Koit Aasumets
- Department of Environmental and Biological Sciences, University of Eastern Finland, FI-80101 Joensuu, Finland
| | - Steffi Goffart
- Department of Environmental and Biological Sciences, University of Eastern Finland, FI-80101 Joensuu, Finland
| | - Jaakko L O Pohjoismäki
- Department of Environmental and Biological Sciences, University of Eastern Finland, FI-80101 Joensuu, Finland
| | - Marcela Dávila López
- Bioinformatics and Data Centre, Sahlgrenska Academy, University of Gothenburg, 41390 Gothenburg, Sweden
| | - Erik Chorell
- Department of Chemistry, Umeå University, 90187 Umeå, Sweden
| | - Sjoerd Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University, 90187 Umeå, Sweden
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3
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Meng F, Jia Z, Zheng J, Ji Y, Wang J, Xiao Y, Fu Y, Wang M, Ling F, Guan MX. A deafness-associated mitochondrial DNA mutation caused pleiotropic effects on DNA replication and tRNA metabolism. Nucleic Acids Res 2022; 50:9453-9469. [PMID: 36039763 PMCID: PMC9458427 DOI: 10.1093/nar/gkac720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 08/09/2022] [Indexed: 12/24/2022] Open
Abstract
In this report, we investigated the molecular mechanism underlying a deafness-associated m.5783C > T mutation that affects the canonical C50-G63 base-pairing of TΨC stem of tRNACys and immediately adjacent to 5' end of light-strand origin of mitochondrial DNA (mtDNA) replication (OriL). Two dimensional agarose gel electrophoresis revealed marked decreases in the replication intermediates including ascending arm of Y-fork arcs spanning OriL in the mutant cybrids bearing m.5783C > T mutation. mtDNA replication alterations were further evidenced by decreased levels of PolγA, Twinkle and SSBP1, newly synthesized mtDNA and mtDNA contents in the mutant cybrids. The m.5783C > T mutation altered tRNACys structure and function, including decreased melting temperature, conformational changes, instability and deficient aminoacylation of mutated tRNACys. The m.5783C > T mutation impaired the 5' end processing efficiency of tRNACys precursors and reduced the levels of tRNACys and downstream tRNATyr. The aberrant tRNA metabolism impaired mitochondrial translation, which was especially pronounced effects in the polypeptides harboring higher numbers of cysteine and tyrosine codons. These alterations led to deficient oxidative phosphorylation including instability and reduced activities of the respiratory chain enzyme complexes I, III, IV and intact supercomplexes overall. Our findings highlight the impact of mitochondrial dysfunction on deafness arising from defects in mitochondrial DNA replication and tRNA metabolism.
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Affiliation(s)
| | | | - Jing Zheng
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, Zhejiang, China,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China,Zhejiang Provincial Key Lab of Genetic and Developmental Disorder, Hangzhou, Zhejiang, China
| | - Yanchun Ji
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, Zhejiang, China,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China,Zhejiang Provincial Key Lab of Genetic and Developmental Disorder, Hangzhou, Zhejiang, China
| | - Jing Wang
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yun Xiao
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yong Fu
- Division of Otolaryngology-Head and Neck Surgery, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Meng Wang
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, Zhejiang, China,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China,Zhejiang Provincial Key Lab of Genetic and Developmental Disorder, Hangzhou, Zhejiang, China
| | - Feng Ling
- Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, Hirosawa 2-1, Wako, Saitama, Japan
| | - Min-Xin Guan
- To whom correspondence should be addressed. Tel: +86 571 88206916; Fax: +86 571 88982377;
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4
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Rahman MM, Young CKJ, Goffart S, Pohjoismäki JLO, Young MJ. Heterozygous p.Y955C mutation in DNA polymerase γ leads to alterations in bioenergetics, complex I subunit expression, and mtDNA replication. J Biol Chem 2022; 298:102196. [PMID: 35760101 PMCID: PMC9307957 DOI: 10.1016/j.jbc.2022.102196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 06/16/2022] [Accepted: 06/17/2022] [Indexed: 12/03/2022] Open
Abstract
In human cells, ATP is generated using oxidative phosphorylation machinery, which is inoperable without proteins encoded by mitochondrial DNA (mtDNA). The DNA polymerase gamma (Polγ) repairs and replicates the multicopy mtDNA genome in concert with additional factors. The Polγ catalytic subunit is encoded by the POLG gene, and mutations in this gene cause mtDNA genome instability and disease. Barriers to studying the molecular effects of disease mutations include scarcity of patient samples and a lack of available mutant models; therefore, we developed a human SJCRH30 myoblast cell line model with the most common autosomal dominant POLG mutation, c.2864A>G/p.Y955C, as individuals with this mutation can present with progressive skeletal muscle weakness. Using on-target sequencing, we detected a 50% conversion frequency of the mutation, confirming heterozygous Y955C substitution. We found mutated cells grew slowly in a glucose-containing medium and had reduced mitochondrial bioenergetics compared with the parental cell line. Furthermore, growing Y955C cells in a galactose-containing medium to obligate mitochondrial function enhanced these bioenergetic deficits. Also, we show complex I NDUFB8 and ND3 protein levels were decreased in the mutant cell line, and the maintenance of mtDNA was severely impaired (i.e., lower copy number, fewer nucleoids, and an accumulation of Y955C-specific replication intermediates). Finally, we show the mutant cells have increased sensitivity to the mitochondrial toxicant 2′-3′-dideoxycytidine. We expect this POLG Y955C cell line to be a robust system to identify new mitochondrial toxicants and therapeutics to treat mitochondrial dysfunction.
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Affiliation(s)
- Md Mostafijur Rahman
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901
| | - Carolyn K J Young
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901
| | - Steffi Goffart
- Department of Environmental and Biological Sciences, University of Eastern Finland, 80101 Joensuu, Finland
| | - Jaakko L O Pohjoismäki
- Department of Environmental and Biological Sciences, University of Eastern Finland, 80101 Joensuu, Finland
| | - Matthew J Young
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901.
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5
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Roy A, Kandettu A, Ray S, Chakrabarty S. Mitochondrial DNA replication and repair defects: Clinical phenotypes and therapeutic interventions. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148554. [PMID: 35341749 DOI: 10.1016/j.bbabio.2022.148554] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 03/06/2022] [Accepted: 03/16/2022] [Indexed: 12/15/2022]
Abstract
Mitochondria is a unique cellular organelle involved in multiple cellular processes and is critical for maintaining cellular homeostasis. This semi-autonomous organelle contains its circular genome - mtDNA (mitochondrial DNA), that undergoes continuous cycles of replication and repair to maintain the mitochondrial genome integrity. The majority of the mitochondrial genes, including mitochondrial replisome and repair genes, are nuclear-encoded. Although the repair machinery of mitochondria is quite efficient, the mitochondrial genome is highly susceptible to oxidative damage and other types of exogenous and endogenous agent-induced DNA damage, due to the absence of protective histones and their proximity to the main ROS production sites. Mutations in replication and repair genes of mitochondria can result in mtDNA depletion and deletions subsequently leading to mitochondrial genome instability. The combined action of mutations and deletions can result in compromised mitochondrial genome maintenance and lead to various mitochondrial disorders. Here, we review the mechanism of mitochondrial DNA replication and repair process, key proteins involved, and their altered function in mitochondrial disorders. The focus of this review will be on the key genes of mitochondrial DNA replication and repair machinery and the clinical phenotypes associated with mutations in these genes.
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Affiliation(s)
- Abhipsa Roy
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Amoolya Kandettu
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Swagat Ray
- Department of Life Sciences, School of Life and Environmental Sciences, University of Lincoln, Lincoln LN6 7TS, United Kingdom
| | - Sanjiban Chakrabarty
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India.
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6
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Morin AL, Win PW, Lin AZ, Castellani CA. Mitochondrial genomic integrity and the nuclear epigenome in health and disease. Front Endocrinol (Lausanne) 2022; 13:1059085. [PMID: 36419771 PMCID: PMC9678080 DOI: 10.3389/fendo.2022.1059085] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/19/2022] [Indexed: 11/09/2022] Open
Abstract
Bidirectional crosstalk between the nuclear and mitochondrial genomes is essential for proper cell functioning. Mitochondrial DNA copy number (mtDNA-CN) and heteroplasmy influence mitochondrial function, which can influence the nuclear genome and contribute to health and disease. Evidence shows that mtDNA-CN and heteroplasmic variation are associated with aging, complex disease, and all-cause mortality. Further, the nuclear epigenome may mediate the effects of mtDNA variation on disease. In this way, mitochondria act as an environmental biosensor translating vital information about the state of the cell to the nuclear genome. Cellular communication between mtDNA variation and the nuclear epigenome can be achieved by modification of metabolites and intermediates of the citric acid cycle and oxidative phosphorylation. These essential molecules (e.g. ATP, acetyl-CoA, ɑ-ketoglutarate and S-adenosylmethionine) act as substrates and cofactors for enzymes involved in epigenetic modifications. The role of mitochondria as an environmental biosensor is emerging as a critical modifier of disease states. Uncovering the mechanisms of these dynamics in disease processes is expected to lead to earlier and improved treatment for a variety of diseases. However, the influence of mtDNA-CN and heteroplasmy variation on mitochondrially-derived epigenome-modifying metabolites and intermediates is poorly understood. This perspective will focus on the relationship between mtDNA-CN, heteroplasmy, and epigenome modifying cofactors and substrates, and the influence of their dynamics on the nuclear epigenome in health and disease.
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Affiliation(s)
- Amanda L. Morin
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Phyo W. Win
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Angela Z. Lin
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Christina A. Castellani
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- *Correspondence: Christina A. Castellani,
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7
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Nomiyama T, Setoyama D, Yasukawa T, Kang D. Mitochondria Metabolomics Reveals a Role of β-Nicotinamide Mononucleotide Metabolism in Mitochondrial DNA Replication. J Biochem 2021; 171:325-338. [PMID: 34865026 DOI: 10.1093/jb/mvab136] [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: 10/25/2021] [Accepted: 11/30/2021] [Indexed: 11/14/2022] Open
Abstract
Mitochondrial DNA (mtDNA) replication is tightly regulated and necessary for cellular homeostasis; however, its relationship with mitochondrial metabolism remains unclear. Advances in metabolomics integrated with the rapid isolation of mitochondria will allow for remarkable progress in analyzing mitochondrial metabolism. Here, we propose a novel methodology for mitochondria-targeted metabolomics, which employs a quick isolation procedure using a hemolytic toxin from Streptococcus pyogenes streptolysin O (SLO). SLO-isolation of mitochondria from cultured HEK293 cells is time- and labor-saving for simultaneous multi-sample processing and has been applied to various other cell lines in this study. Furthermore, our method can detect the time-dependent reduction in mitochondrial ATP in response to a glycolytic inhibitor 2-deoxyglucose, indicating the suitability to prepare metabolite analysis-competent mitochondria. Using this methodology, we searched for specific mitochondrial metabolites associated with mtDNA replication activation, and nucleotides and NAD+ were identified to be prominently altered. Most notably, treatment of β-Nicotinamide Mononucleotide (β-NMN), a precursor of NAD+, to HEK293 cells activated and improved the rate of mtDNA replication by increasing nucleotides in mitochondria and decreasing their degradation products: nucleosides. Our results suggest that β-NMN metabolism play a role in supporting mtDNA replication by maintaining the nucleotide pool balance in the mitochondria.
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Affiliation(s)
- Tomoko Nomiyama
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka, Japan.,Department of Clinical Chemistry and Laboratory Medicine, Kyushu University Hospital, 3-1-1 Maidashi, Fukuoka, Japan
| | - Daiki Setoyama
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka, Japan.,Department of Clinical Chemistry and Laboratory Medicine, Kyushu University Hospital, 3-1-1 Maidashi, Fukuoka, Japan
| | - Takehiro Yasukawa
- Department of Pathology and Oncology, Juntendo University School of Medicine, 2-1-1 Hongo, Tokyo, Japan
| | - Dongchon Kang
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka, Japan.,Department of Clinical Chemistry and Laboratory Medicine, Kyushu University Hospital, 3-1-1 Maidashi, Fukuoka, Japan
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8
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DNA2 in Chromosome Stability and Cell Survival-Is It All about Replication Forks? Int J Mol Sci 2021; 22:ijms22083984. [PMID: 33924313 PMCID: PMC8069077 DOI: 10.3390/ijms22083984] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/08/2021] [Accepted: 04/10/2021] [Indexed: 01/16/2023] Open
Abstract
The conserved nuclease-helicase DNA2 has been linked to mitochondrial myopathy, Seckel syndrome, and cancer. Across species, the protein is indispensable for cell proliferation. On the molecular level, DNA2 has been implicated in DNA double-strand break (DSB) repair, checkpoint activation, Okazaki fragment processing (OFP), and telomere homeostasis. More recently, a critical contribution of DNA2 to the replication stress response and recovery of stalled DNA replication forks (RFs) has emerged. Here, we review the available functional and phenotypic data and propose that the major cellular defects associated with DNA2 dysfunction, and the links that exist with human disease, can be rationalized through the fundamental importance of DNA2-dependent RF recovery to genome duplication. Being a crucial player at stalled RFs, DNA2 is a promising target for anti-cancer therapy aimed at eliminating cancer cells by replication-stress overload.
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9
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Lakshmanan LN, Yee Z, Halliwell B, Gruber J, Gunawan R. Thermodynamic analysis of DNA hybridization signatures near mitochondrial DNA deletion breakpoints. iScience 2021; 24:102138. [PMID: 33665557 PMCID: PMC7900216 DOI: 10.1016/j.isci.2021.102138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 01/14/2021] [Accepted: 01/29/2021] [Indexed: 11/17/2022] Open
Abstract
Broad evidence in the literature supports double-strand breaks (DSBs) as initiators of mitochondrial DNA (mtDNA) deletion mutations. While DNA misalignment during DSB repair is commonly proposed as the mechanism by which DSBs cause deletion mutations, details such as the specific DNA repair errors are still lacking. Here, we used DNA hybridization thermodynamics to infer the sequence lengths of mtDNA misalignments that are associated with mtDNA deletions. We gathered and analyzed 9,921 previously reported mtDNA deletion breakpoints in human, rhesus monkey, mouse, rat, and Caenorhabditis elegans. Our analysis shows that a large fraction of mtDNA breakpoint positions can be explained by the thermodynamics of short ≤ 5-nt misalignments. The significance of short DNA misalignments supports an important role for erroneous non-homologous and micro-homology-dependent DSB repair in mtDNA deletion formation. The consistency of the results of our analysis across species further suggests a shared mode of mtDNA deletion mutagenesis.
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Affiliation(s)
- Lakshmi Narayanan Lakshmanan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
- Institute for Chemical and Bioengineering, ETH Zurich, Zurich, Switzerland
| | - Zhuangli Yee
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Barry Halliwell
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jan Gruber
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Ageing Research Laboratory, Science Division, Yale-NUS College, Singapore, Singapore
| | - Rudiyanto Gunawan
- Department of Chemical and Biological Engineering, University at Buffalo, Buffalo, NY, USA
- Corresponding author
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10
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Fontana GA, Gahlon HL. Mechanisms of replication and repair in mitochondrial DNA deletion formation. Nucleic Acids Res 2020; 48:11244-11258. [PMID: 33021629 PMCID: PMC7672454 DOI: 10.1093/nar/gkaa804] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 09/07/2020] [Accepted: 09/25/2020] [Indexed: 02/06/2023] Open
Abstract
Deletions in mitochondrial DNA (mtDNA) are associated with diverse human pathologies including cancer, aging and mitochondrial disorders. Large-scale deletions span kilobases in length and the loss of these associated genes contributes to crippled oxidative phosphorylation and overall decline in mitochondrial fitness. There is not a united view for how mtDNA deletions are generated and the molecular mechanisms underlying this process are poorly understood. This review discusses the role of replication and repair in mtDNA deletion formation as well as nucleic acid motifs such as repeats, secondary structures, and DNA damage associated with deletion formation in the mitochondrial genome. We propose that while erroneous replication and repair can separately contribute to deletion formation, crosstalk between these pathways is also involved in generating deletions.
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Affiliation(s)
- Gabriele A Fontana
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Hailey L Gahlon
- To whom correspondence should be addressed. Tel: +41 44 632 3731;
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11
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Piro-Mégy C, Sarzi E, Tarrés-Solé A, Péquignot M, Hensen F, Quilès M, Manes G, Chakraborty A, Sénéchal A, Bocquet B, Cazevieille C, Roubertie A, Müller A, Charif M, Goudenège D, Lenaers G, Wilhelm H, Kellner U, Weisschuh N, Wissinger B, Zanlonghi X, Hamel C, Spelbrink JN, Sola M, Delettre C. Dominant mutations in mtDNA maintenance gene SSBP1 cause optic atrophy and foveopathy. J Clin Invest 2020; 130:143-156. [PMID: 31550237 PMCID: PMC6934222 DOI: 10.1172/jci128513] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 09/19/2019] [Indexed: 01/20/2023] Open
Abstract
Mutations in genes encoding components of the mitochondrial DNA (mtDNA) replication machinery cause mtDNA depletion syndromes (MDSs), which associate ocular features with severe neurological syndromes. Here, we identified heterozygous missense mutations in single-strand binding protein 1 (SSBP1) in 5 unrelated families, leading to the R38Q and R107Q amino acid changes in the mitochondrial single-stranded DNA-binding protein, a crucial protein involved in mtDNA replication. All affected individuals presented optic atrophy, associated with foveopathy in half of the cases. To uncover the structural features underlying SSBP1 mutations, we determined a revised SSBP1 crystal structure. Structural analysis suggested that both mutations affect dimer interactions and presumably distort the DNA-binding region. Using patient fibroblasts, we validated that the R38Q variant destabilizes SSBP1 dimer/tetramer formation, affects mtDNA replication, and induces mtDNA depletion. Our study showing that mutations in SSBP1 cause a form of dominant optic atrophy frequently accompanied with foveopathy brings insights into mtDNA maintenance disorders.
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Affiliation(s)
- Camille Piro-Mégy
- Institute of Neurosciences of Montpellier, INSERM, University of Montpellier, Montpellier, France
| | - Emmanuelle Sarzi
- Institute of Neurosciences of Montpellier, INSERM, University of Montpellier, Montpellier, France
| | - Aleix Tarrés-Solé
- Structural MitoLab, Department of Structural Biology, "Maria de Maeztu" Unit of Excellence, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona, Spain
| | - Marie Péquignot
- Institute of Neurosciences of Montpellier, INSERM, University of Montpellier, Montpellier, France
| | - Fenna Hensen
- Radboud Center for Mitochondrial Medicine, Department of Paediatrics, Radboudumc, Nijmegen, Netherlands
| | - Mélanie Quilès
- Institute of Neurosciences of Montpellier, INSERM, University of Montpellier, Montpellier, France
| | - Gaël Manes
- Institute of Neurosciences of Montpellier, INSERM, University of Montpellier, Montpellier, France
| | - Arka Chakraborty
- Structural MitoLab, Department of Structural Biology, "Maria de Maeztu" Unit of Excellence, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona, Spain
| | - Audrey Sénéchal
- Institute of Neurosciences of Montpellier, INSERM, University of Montpellier, Montpellier, France
| | - Béatrice Bocquet
- Institute of Neurosciences of Montpellier, INSERM, University of Montpellier, Montpellier, France.,CHU Montpellier, Centre of Reference for Genetic Sensory Diseases, Gui de Chauliac Hospital, Montpellier, France
| | - Chantal Cazevieille
- Institute of Neurosciences of Montpellier, INSERM, University of Montpellier, Montpellier, France
| | - Agathe Roubertie
- Institute of Neurosciences of Montpellier, INSERM, University of Montpellier, Montpellier, France.,CHU Montpellier, Centre of Reference for Genetic Sensory Diseases, Gui de Chauliac Hospital, Montpellier, France
| | - Agnès Müller
- Institute of Neurosciences of Montpellier, INSERM, University of Montpellier, Montpellier, France.,Faculté de Pharmacie, Université de Montpellier, Montpellier, France
| | - Majida Charif
- UMR CNRS 6015-INSERM U1083, MitoVasc Institute, Angers University, Angers, France
| | - David Goudenège
- UMR CNRS 6015-INSERM U1083, MitoVasc Institute, Angers University, Angers, France
| | - Guy Lenaers
- UMR CNRS 6015-INSERM U1083, MitoVasc Institute, Angers University, Angers, France
| | - Helmut Wilhelm
- University Eye Hospital, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Ulrich Kellner
- Rare Retinal Disease Center, AugenZentrum Siegburg, MVZ Augenärztliches Diagnostik- und Therapiecentrum Siegburg GmbH, Siegburg, Germany
| | - Nicole Weisschuh
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Xavier Zanlonghi
- Centre de Compétence Maladie Rares, Clinique Pluridisciplinaire Jules Verne, Nantes, France
| | - Christian Hamel
- Institute of Neurosciences of Montpellier, INSERM, University of Montpellier, Montpellier, France.,CHU Montpellier, Centre of Reference for Genetic Sensory Diseases, Gui de Chauliac Hospital, Montpellier, France
| | - Johannes N Spelbrink
- Radboud Center for Mitochondrial Medicine, Department of Paediatrics, Radboudumc, Nijmegen, Netherlands
| | - Maria Sola
- Structural MitoLab, Department of Structural Biology, "Maria de Maeztu" Unit of Excellence, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona, Spain
| | - Cécile Delettre
- Institute of Neurosciences of Montpellier, INSERM, University of Montpellier, Montpellier, France
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12
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Hu B, Yang M, Liao Z, Wei H, Zhao C, Li D, Hu S, Jiang X, Shi M, Luo Q, Zhang D, Nie Q, Zhang X, Li H. Mutation of TWNK Gene Is One of the Reasons of Runting and Stunting Syndrome Characterized by mtDNA Depletion in Sex-Linked Dwarf Chicken. Front Cell Dev Biol 2020; 8:581. [PMID: 32766243 PMCID: PMC7381202 DOI: 10.3389/fcell.2020.00581] [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: 02/14/2020] [Accepted: 06/16/2020] [Indexed: 11/16/2022] Open
Abstract
Runting and stunting syndrome (RSS), which is characterized by low body weight, generally occurs early in life and leads to considerable economic losses in the commercial broiler industry. Our previous study has suggested that RSS is associated with mitochondria dysfunction in sex-linked dwarf (SLD) chickens. However, the molecular mechanism of RSS remains unknown. Based on the molecular diagnostics of mitochondrial diseases, we identified a recessive mutation c. 409G > A (p. Ala137Thr) of Twinkle mitochondrial DNA helicase (TWNK) gene and mitochondrial DNA (mtDNA) depletion in RSS chickens’ livers from strain N301. Bioinformatics investigations supported the pathogenicity of the TWNK mutation that is located on the extended peptide linker of Twinkle primase domain and might further lead to mtDNA depletion in chicken. Furthermore, overexpression of wild-type TWNK increases mtDNA copy number, whereas overexpression of TWNK A137T causes mtDNA depletion in vitro. Additionally, the TWNK c. 409G > A mutation showed significant associations with body weight, daily gain, pectoralis weight, crureus weight, and abdominal fat weight. Taken together, we corroborated that the recessive TWNK c. 409G > A (p. Ala137Thr) mutation is associated with RSS characterized by mtDNA depletion in SLD chicken.
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Affiliation(s)
- Bowen Hu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Minmin Yang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Zhiying Liao
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Haohui Wei
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Changbin Zhao
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Dajian Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Shuang Hu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | | | - Meiqing Shi
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, United States
| | - Qingbin Luo
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Dexiang Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Qinghua Nie
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Xiquan Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
| | - Hongmei Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of AgroAnimal Genomics and Molecular Breeding and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, China
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13
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Peter B, Falkenberg M. TWINKLE and Other Human Mitochondrial DNA Helicases: Structure, Function and Disease. Genes (Basel) 2020; 11:genes11040408. [PMID: 32283748 PMCID: PMC7231222 DOI: 10.3390/genes11040408] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/06/2020] [Accepted: 04/07/2020] [Indexed: 12/30/2022] Open
Abstract
Mammalian mitochondria contain a circular genome (mtDNA) which encodes subunits of the oxidative phosphorylation machinery. The replication and maintenance of mtDNA is carried out by a set of nuclear-encoded factors—of which, helicases form an important group. The TWINKLE helicase is the main helicase in mitochondria and is the only helicase required for mtDNA replication. Mutations in TWINKLE cause a number of human disorders associated with mitochondrial dysfunction, neurodegeneration and premature ageing. In addition, a number of other helicases with a putative role in mitochondria have been identified. In this review, we discuss our current knowledge of TWINKLE structure and function and its role in diseases of mtDNA maintenance. We also briefly discuss other potential mitochondrial helicases and postulate on their role(s) in mitochondria.
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14
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Oliveira MT, Pontes CDB, Ciesielski GL. Roles of the mitochondrial replisome in mitochondrial DNA deletion formation. Genet Mol Biol 2020; 43:e20190069. [PMID: 32141473 PMCID: PMC7197994 DOI: 10.1590/1678-4685-gmb-2019-0069] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 08/12/2019] [Indexed: 01/07/2023] Open
Abstract
Mitochondrial DNA (mtDNA) deletions are a common cause of human mitochondrial
diseases. Mutations in the genes encoding components of the mitochondrial
replisome, such as DNA polymerase gamma (Pol γ) and the mtDNA helicase Twinkle,
have been associated with the accumulation of such deletions and the development
of pathological conditions in humans. Recently, we demonstrated that changes in
the level of wild-type Twinkle promote mtDNA deletions, which implies that not
only mutations in, but also dysregulation of the stoichiometry between the
replisome components is potentially pathogenic. The mechanism(s) by which
alterations to the replisome function generate mtDNA deletions is(are) currently
under debate. It is commonly accepted that stalling of the replication fork at
sites likely to form secondary structures precedes the deletion formation. The
secondary structural elements can be bypassed by the replication-slippage
mechanism. Otherwise, stalling of the replication fork can generate single- and
double-strand breaks, which can be repaired through recombination leading to the
elimination of segments between the recombination sites. Here, we discuss
aberrances of the replisome in the context of the two debated outcomes, and
suggest new mechanistic explanations based on replication restart and template
switching that could account for all the deletion types reported for
patients.
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Affiliation(s)
- Marcos T Oliveira
- Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Ciências Agrárias e Veterinárias, Departamento de Tecnologia, Jaboticabal, SP, Brazil
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15
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Cluett TJ, Akman G, Reyes A, Kazak L, Mitchell A, Wood SR, Spinazzola A, Spelbrink JN, Holt IJ. Transcript availability dictates the balance between strand-asynchronous and strand-coupled mitochondrial DNA replication. Nucleic Acids Res 2019; 46:10771-10781. [PMID: 30239839 PMCID: PMC6237803 DOI: 10.1093/nar/gky852] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 09/12/2018] [Indexed: 11/15/2022] Open
Abstract
Mammalian mitochondria operate multiple mechanisms of DNA replication. In many cells and tissues a strand-asynchronous mechanism predominates over coupled leading and lagging-strand DNA synthesis. However, little is known of the factors that control or influence the different mechanisms of replication, and the idea that strand-asynchronous replication entails transient incorporation of transcripts (aka bootlaces) is controversial. A firm prediction of the bootlace model is that it depends on mitochondrial transcripts. Here, we show that elevated expression of Twinkle DNA helicase in human mitochondria induces bidirectional, coupled leading and lagging-strand DNA synthesis, at the expense of strand-asynchronous replication; and this switch is accompanied by decreases in the steady-state level of some mitochondrial transcripts. However, in the so-called minor arc of mitochondrial DNA where transcript levels remain high, the strand-asynchronous replication mechanism is instated. Hence, replication switches to a strand-coupled mechanism only where transcripts are scarce, thereby establishing a direct correlation between transcript availability and the mechanism of replication. Thus, these findings support a critical role of mitochondrial transcripts in the strand-asynchronous mechanism of mitochondrial DNA replication; and, as a corollary, mitochondrial RNA availability and RNA/DNA hybrid formation offer means of regulating the mechanisms of DNA replication in the organelle.
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Affiliation(s)
- Tricia J Cluett
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB1 9SY, UK
| | | | - Aurelio Reyes
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB1 9SY, UK
| | - Lawrence Kazak
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB1 9SY, UK
| | - Alice Mitchell
- Department of Clinical Movement Neurosciences, Institute of Neurology, Royal Free Campus, University College London, London NW3 2PF, UK
| | - Stuart R Wood
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB1 9SY, UK
| | - Antonella Spinazzola
- Department of Clinical Movement Neurosciences, Institute of Neurology, Royal Free Campus, University College London, London NW3 2PF, UK.,MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
| | - Johannes N Spelbrink
- Department of Pediatrics, Radboud Centre for Mitochondrial Medicine, Radboud University Medical Centre, Geert Grooteplein 10, 6500 HB, Nijmegen, The Netherlands
| | - Ian J Holt
- Department of Clinical Movement Neurosciences, Institute of Neurology, Royal Free Campus, University College London, London NW3 2PF, UK.,Biodonostia Health Research Institute, 20014 San Sebastián, Spain and IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
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16
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Ciesielski GL, Nadalutti CA, Oliveira MT, Jacobs HT, Griffith JD, Kaguni LS. Structural rearrangements in the mitochondrial genome of Drosophila melanogaster induced by elevated levels of the replicative DNA helicase. Nucleic Acids Res 2019; 46:3034-3046. [PMID: 29432582 PMCID: PMC5887560 DOI: 10.1093/nar/gky094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 02/02/2018] [Indexed: 01/10/2023] Open
Abstract
Pathological conditions impairing functions of mitochondria often lead to compensatory upregulation of the mitochondrial DNA (mtDNA) replisome machinery, and the replicative DNA helicase appears to be a key factor in regulating mtDNA copy number. Moreover, mtDNA helicase mutations have been associated with structural rearrangements of the mitochondrial genome. To evaluate the effects of elevated levels of the mtDNA helicase on the integrity and replication of the mitochondrial genome, we overexpressed the helicase in Drosophila melanogaster Schneider cells and analyzed the mtDNA by two-dimensional neutral agarose gel electrophoresis and electron microscopy. We found that elevation of mtDNA helicase levels increases the quantity of replication intermediates and alleviates pausing at the replication slow zones. Though we did not observe a concomitant alteration in mtDNA copy number, we observed deletions specific to the segment of repeated elements in the immediate vicinity of the origin of replication, and an accumulation of species characteristic of replication fork stalling. We also found elevated levels of RNA that are retained in the replication intermediates. Together, our results suggest that upregulation of mtDNA helicase promotes the process of mtDNA replication but also results in genome destabilization.
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Affiliation(s)
- Grzegorz L Ciesielski
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI, USA.,Institute of Biosciences and Medical Technology, University of Tampere, FI-33014 Tampere, Finland
| | - Cristina A Nadalutti
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Marcos T Oliveira
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI, USA
| | - Howard T Jacobs
- Institute of Biosciences and Medical Technology, University of Tampere, FI-33014 Tampere, Finland.,Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland
| | - Jack D Griffith
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Laurie S Kaguni
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, MI, USA.,Institute of Biosciences and Medical Technology, University of Tampere, FI-33014 Tampere, Finland
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17
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Abstract
Replication stalling has been associated with the formation of pathological mitochondrial DNA (mtDNA) rearrangements. Yet, almost nothing is known about the fate of stalled replication intermediates in mitochondria. We show here that replication stalling in mitochondria leads to replication fork regression and mtDNA double-strand breaks. The resulting mtDNA fragments are normally degraded by a mechanism involving the mitochondrial exonuclease MGME1, and the loss of this enzyme results in accumulation of linear and recombining mtDNA species. Additionally, replication stress promotes the initiation of alternative replication origins as an apparent means of rescue by fork convergence. Besides demonstrating an interplay between two major mechanisms rescuing stalled replication forks – mtDNA degradation and homology-dependent repair – our data provide evidence that mitochondria employ similar mechanisms to cope with replication stress as known from other genetic systems.
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18
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Hangas A, Aasumets K, Kekäläinen NJ, Paloheinä M, Pohjoismäki JL, Gerhold JM, Goffart S. Ciprofloxacin impairs mitochondrial DNA replication initiation through inhibition of Topoisomerase 2. Nucleic Acids Res 2018; 46:9625-9636. [PMID: 30169847 PMCID: PMC6182158 DOI: 10.1093/nar/gky793] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/21/2018] [Accepted: 08/23/2018] [Indexed: 11/17/2022] Open
Abstract
Maintenance of topological homeostasis is vital for gene expression and genome replication in all organisms. Similar to other circular genomes, also mitochondrial DNA (mtDNA) is known to exist in various different topological forms, although their functional significance remains unknown. We report here that both known type II topoisomerases Top2α and Top2β are present in mammalian mitochondria, with especially Top2β regulating the supercoiling state of mtDNA. Loss of Top2β or its inhibition by ciprofloxacin results in accumulation of positively supercoiled mtDNA, followed by cessation of mitochondrial transcription and replication initiation, causing depletion of mtDNA copy number. These mitochondrial effects block both cell proliferation and differentiation, possibly explaining some of the side effects associated with fluoroquinolone antibiotics. Our results show for the first time the importance of topology for maintenance of mtDNA homeostasis and provide novel insight into the mitochondrial effects of fluoroquinolones.
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Affiliation(s)
- Anu Hangas
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
| | - Koit Aasumets
- Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Nina J Kekäläinen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
| | - Mika Paloheinä
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
| | - Jaakko L Pohjoismäki
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
| | - Joachim M Gerhold
- Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Steffi Goffart
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
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19
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Pohjoismäki JLO, Forslund JME, Goffart S, Torregrosa-Muñumer R, Wanrooij S. Known Unknowns of Mammalian Mitochondrial DNA Maintenance. Bioessays 2018; 40:e1800102. [DOI: 10.1002/bies.201800102] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 06/18/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Jaakko L. O. Pohjoismäki
- Department of Environmental and Biological Sciences, University of Eastern Finland; 80101 Joensuu Finland
| | | | - Steffi Goffart
- Department of Environmental and Biological Sciences, University of Eastern Finland; 80101 Joensuu Finland
| | - Rubén Torregrosa-Muñumer
- Department of Environmental and Biological Sciences, University of Eastern Finland; 80101 Joensuu Finland
| | - Sjoerd Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University; 90187 Umeå Sweden
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20
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Peralta S, Goffart S, Williams SL, Diaz F, Garcia S, Nissanka N, Area-Gomez E, Pohjoismäki J, Moraes CT. ATAD3 controls mitochondrial cristae structure in mouse muscle, influencing mtDNA replication and cholesterol levels. J Cell Sci 2018; 131:jcs217075. [PMID: 29898916 PMCID: PMC6051345 DOI: 10.1242/jcs.217075] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/30/2018] [Indexed: 01/01/2023] Open
Abstract
Mutations in the mitochondrial inner membrane ATPase ATAD3A result in neurological syndromes in humans. In mice, the ubiquitous disruption of Atad3 (also known as Atad3a) was embryonic lethal, but a skeletal muscle-specific conditional knockout (KO) was viable. At birth, ATAD3 muscle KO mice had normal weight, but from 2 months onwards they showed progressive motor-impaired coordination and weakness. Loss of ATAD3 caused early and severe mitochondrial structural abnormalities, mitochondrial proliferation and muscle atrophy. There was dramatic reduction in mitochondrial cristae junctions and overall cristae morphology. The lack of mitochondrial cristae was accompanied by a reduction in high molecular weight mitochondrial contact site and cristae organizing system (MICOS) complexes, and to a lesser extent in OPA1. Moreover, muscles lacking ATAD3 showed altered cholesterol metabolism, accumulation of mitochondrial DNA (mtDNA) replication intermediates, progressive mtDNA depletion and deletions. Unexpectedly, decreases in the levels of some OXPHOS components occurred after cristae destabilization, indicating that ATAD3 is not crucial for mitochondrial translation, as previously suggested. Our results show a critical early role of ATAD3 in regulating mitochondrial inner membrane structure, leading to secondary defects in mtDNA replication and complex V and cholesterol levels in postmitotic tissue.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Susana Peralta
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Steffi Goffart
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu 80101, Finland
| | - Sion L Williams
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Francisca Diaz
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Sofia Garcia
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Nadee Nissanka
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Estela Area-Gomez
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - Jaakko Pohjoismäki
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu 80101, Finland
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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21
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Hoxhaj G, Hughes-Hallett J, Timson RC, Ilagan E, Yuan M, Asara JM, Ben-Sahra I, Manning BD. The mTORC1 Signaling Network Senses Changes in Cellular Purine Nucleotide Levels. Cell Rep 2018; 21:1331-1346. [PMID: 29091770 DOI: 10.1016/j.celrep.2017.10.029] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/22/2017] [Accepted: 10/06/2017] [Indexed: 12/11/2022] Open
Abstract
Mechanistic (or mammalian) target of rapamycin complex 1 (mTORC1) integrates signals from growth factors and nutrients to control biosynthetic processes, including protein, lipid, and nucleic acid synthesis. We find that the mTORC1 pathway is responsive to changes in purine nucleotides in a manner analogous to its sensing of amino acids. Depletion of cellular purines, but not pyrimidines, inhibits mTORC1, and restoration of intracellular adenine nucleotides via addition of exogenous purine nucleobases or nucleosides acutely reactivates mTORC1. Adenylate sensing by mTORC1 is dependent on the tuberous sclerosis complex (TSC) protein complex and its regulation of Rheb upstream of mTORC1, but independent of energy stress and AMP-activated protein kinase (AMPK). Even though mTORC1 signaling is not acutely sensitive to changes in intracellular guanylates, long-term depletion of guanylates decreases Rheb protein levels. Our findings suggest that nucleotide sensing, like amino acid sensing, enables mTORC1 to tightly coordinate nutrient availability with the synthesis of macromolecules, such as protein and nucleic acids, produced from those nutrients.
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Affiliation(s)
- Gerta Hoxhaj
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - James Hughes-Hallett
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Rebecca C Timson
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Erika Ilagan
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Min Yuan
- Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - John M Asara
- Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Issam Ben-Sahra
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Brendan D Manning
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA.
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22
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Shen G, Li S, Cui W, Liu S, Liu Q, Yang Y, Gross M, Li W. Stabilization of warfarin-binding pocket of VKORC1 and VKORL1 by a peripheral region determines their different sensitivity to warfarin inhibition. J Thromb Haemost 2018; 16:1164-1175. [PMID: 29665197 PMCID: PMC6231229 DOI: 10.1111/jth.14127] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Indexed: 11/30/2022]
Abstract
Essentials VKORL1 and VKORC1 have a similar overall structure and warfarin-binding pocket. A peripheral region stabilizing this pocket controls warfarin sensitivity of the VKOR paralogs. A human single nucleotide polymorphism in this region renders VKORL1 sensitive to warfarin. A group of warfarin-resistant mutations in VKORC1 acts by disrupting peripheral interactions. SUMMARY Background The human genome encodes two paralogs of vitamin-K-epoxide reductase, VKORC1 and VKORL1, that support blood coagulation and other vitamin-K-dependent processes. Warfarin inhibits both enzymes, but VKORL1 is relatively resistant to warfarin. Objectives To understand the difference between VKORL1 and VKORC1, and the cause of warfarin-resistant (WR) mutations in VKORC1. Methods We performed systematic mutagenesis and analyzed warfarin responses with a cell-based activity assay. Mass spectrometry analyses were used to detect cellular redox state. Results VKORC1 and VKORL1 adopt a similar intracellular redox state with four-transmembrane-helix topology. Most WR mutations identified in VKORC1 also confer resistance in VKORL1, indicating that warfarin inhibits these paralogs at a common binding site. A group of WR mutations, distant from the warfarin-binding site, show significantly less resistance in VKORL1 than in VKORC1, implying that their different warfarin responses are determined by peripheral interactions. Remarkably, we identify a critical peripheral region in which single mutations, Glu37Lys or His46Tyr, drastically increase the warfarin sensitivity of VKORL1. In the background of these warfarin-sensitive VKORL1 mutants, WR mutations showing relative less resistance in wild-type VKORL1 become much more resistant, suggesting a structural conversion to resemble VKORC1. At this peripheral region, we also identified a human single nucleotide polymorphism that confers warfarin sensitivity of VKORL1. Conclusions Peripheral regions of VKORC1 and VKORL1 primarily maintain the stability of their common warfarin-binding pocket, and differences of such interactions determine their relative sensitivity to warfarin inhibition. This new model also explains most WR mutations located at the peripheral regions of VKORC1.
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Affiliation(s)
- G Shen
- Institute of Hemostasis and Thrombosis, College of Medicine, Henan University of Science and Technology, Luoyang, Henan, China
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - S Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - W Cui
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, USA
| | - S Liu
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Q Liu
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
- Department of Forensic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Y Yang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - M Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, USA
| | - W Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
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23
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Lozoya OA, Martinez-Reyes I, Wang T, Grenet D, Bushel P, Li J, Chandel N, Woychik RP, Santos JH. Mitochondrial nicotinamide adenine dinucleotide reduced (NADH) oxidation links the tricarboxylic acid (TCA) cycle with methionine metabolism and nuclear DNA methylation. PLoS Biol 2018; 16:e2005707. [PMID: 29668680 PMCID: PMC5927466 DOI: 10.1371/journal.pbio.2005707] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/30/2018] [Accepted: 03/28/2018] [Indexed: 01/28/2023] Open
Abstract
Mitochondrial function affects many aspects of cellular physiology, and, most recently, its role in epigenetics has been reported. Mechanistically, how mitochondrial function alters DNA methylation patterns in the nucleus remains ill defined. Using a cell culture model of induced mitochondrial DNA (mtDNA) depletion, in this study we show that progressive mitochondrial dysfunction leads to an early transcriptional and metabolic program centered on the metabolism of various amino acids, including those involved in the methionine cycle. We find that this program also increases DNA methylation, which occurs primarily in the genes that are differentially expressed. Maintenance of mitochondrial nicotinamide adenine dinucleotide reduced (NADH) oxidation in the context of mtDNA loss rescues methionine salvage and polyamine synthesis and prevents changes in DNA methylation and gene expression but does not affect serine/folate metabolism or transsulfuration. This work provides a novel mechanistic link between mitochondrial function and epigenetic regulation of gene expression that involves polyamine and methionine metabolism responding to changes in the tricarboxylic acid (TCA) cycle. Given the implications of these findings, future studies across different physiological contexts and in vivo are warranted.
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Affiliation(s)
- Oswaldo A. Lozoya
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, North Carolina, United States of America
| | - Inmaculada Martinez-Reyes
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Tianyuan Wang
- Integrative Bioinformatics Group, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, North Carolina, United States of America
| | - Dagoberto Grenet
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, North Carolina, United States of America
| | - Pierre Bushel
- Biostatistics and Computational Biology Group, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, North Carolina, United States of America
| | - Jianying Li
- Integrative Bioinformatics Group, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, North Carolina, United States of America
| | - Navdeep Chandel
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Richard P. Woychik
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, North Carolina, United States of America
- * E-mail: (JHS); (RPW)
| | - Janine H. Santos
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, North Carolina, United States of America
- * E-mail: (JHS); (RPW)
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24
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Szczesny RJ, Kowalska K, Klosowska-Kosicka K, Chlebowski A, Owczarek EP, Warkocki Z, Kulinski TM, Adamska D, Affek K, Jedroszkowiak A, Kotrys AV, Tomecki R, Krawczyk PS, Borowski LS, Dziembowski A. Versatile approach for functional analysis of human proteins and efficient stable cell line generation using FLP-mediated recombination system. PLoS One 2018; 13:e0194887. [PMID: 29590189 PMCID: PMC5874048 DOI: 10.1371/journal.pone.0194887] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 03/12/2018] [Indexed: 12/21/2022] Open
Abstract
Deciphering a function of a given protein requires investigating various biological aspects. Usually, the protein of interest is expressed with a fusion tag that aids or allows subsequent analyses. Additionally, downregulation or inactivation of the studied gene enables functional studies. Development of the CRISPR/Cas9 methodology opened many possibilities but in many cases it is restricted to non-essential genes. Recombinase-dependent gene integration methods, like the Flp-In system, are very good alternatives. The system is widely used in different research areas, which calls for the existence of compatible vectors and efficient protocols that ensure straightforward DNA cloning and generation of stable cell lines. We have created and validated a robust series of 52 vectors for streamlined generation of stable mammalian cell lines using the FLP recombinase-based methodology. Using the sequence-independent DNA cloning method all constructs for a given coding-sequence can be made with just three universal PCR primers. Our collection allows tetracycline-inducible expression of proteins with various tags suitable for protein localization, FRET, bimolecular fluorescence complementation (BiFC), protein dynamics studies (FRAP), co-immunoprecipitation, the RNA tethering assay and cell sorting. Some of the vectors contain a bidirectional promoter for concomitant expression of miRNA and mRNA, so that a gene can be silenced and its product replaced by a mutated miRNA-insensitive version. Our toolkit and protocols have allowed us to create more than 500 constructs with ease. We demonstrate the efficacy of our vectors by creating stable cell lines with various tagged proteins (numatrin, fibrillarin, coilin, centrin, THOC5, PCNA). We have analysed transgene expression over time to provide a guideline for future experiments and compared the effectiveness of commonly used inducers for tetracycline-responsive promoters. As proof of concept we examined the role of the exoribonuclease XRN2 in transcription termination by RNAseq.
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Affiliation(s)
- Roman J. Szczesny
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
- * E-mail: (RJS); (AD)
| | - Katarzyna Kowalska
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Kamila Klosowska-Kosicka
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Aleksander Chlebowski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Ewelina P. Owczarek
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Zbigniew Warkocki
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Tomasz M. Kulinski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Dorota Adamska
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Kamila Affek
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Agata Jedroszkowiak
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Anna V. Kotrys
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Rafal Tomecki
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Pawel S. Krawczyk
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Lukasz S. Borowski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Andrzej Dziembowski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
- * E-mail: (RJS); (AD)
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25
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RAD51C/XRCC3 Facilitates Mitochondrial DNA Replication and Maintains Integrity of the Mitochondrial Genome. Mol Cell Biol 2018; 38:MCB.00489-17. [PMID: 29158291 DOI: 10.1128/mcb.00489-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 11/10/2017] [Indexed: 12/12/2022] Open
Abstract
Mechanisms underlying mitochondrial genome maintenance have recently gained wide attention, as mutations in mitochondrial DNA (mtDNA) lead to inherited muscular and neurological diseases, which are linked to aging and cancer. It was previously reported that human RAD51, RAD51C, and XRCC3 localize to mitochondria upon oxidative stress and are required for the maintenance of mtDNA stability. Since RAD51 and RAD51 paralogs are spontaneously imported into mitochondria, their precise role in mtDNA maintenance under unperturbed conditions remains elusive. Here, we show that RAD51C/XRCC3 is an additional component of the mitochondrial nucleoid having nucleus-independent roles in mtDNA maintenance. RAD51C/XRCC3 localizes to the mtDNA regulatory regions in the D-loop along with the mitochondrial polymerase POLG, and this recruitment is dependent upon Twinkle helicase. Moreover, upon replication stress, RAD51C and XRCC3 are further enriched at the mtDNA mutation hot spot region D310. Notably, the absence of RAD51C/XRCC3 affects the stability of POLG on mtDNA. As a consequence, RAD51C/XRCC3-deficient cells exhibit reduced mtDNA synthesis and increased lesions in the mitochondrial genome, leading to overall unhealthy mitochondria. Together, these findings lead to the proposal of a mechanism for a direct role of RAD51C/XRCC3 in maintaining mtDNA integrity under replication stress conditions.
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26
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Herbers E, Kekäläinen NJ, Hangas A, Pohjoismäki JL, Goffart S. Tissue specific differences in mitochondrial DNA maintenance and expression. Mitochondrion 2018; 44:85-92. [PMID: 29339192 DOI: 10.1016/j.mito.2018.01.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 01/05/2018] [Accepted: 01/11/2018] [Indexed: 01/17/2023]
Abstract
The different cell types of multicellular organisms have specialized physiological requirements, affecting also their mitochondrial energy production and metabolism. The genome of mitochondria is essential for mitochondrial oxidative phosphorylation (OXHPOS) and thus plays a central role in many human mitochondrial pathologies. Disorders affecting mitochondrial DNA (mtDNA) maintenance are typically resulting in a tissue-specific pattern of mtDNA deletions and rearrangements. Despite this role in disease as well as a biomarker of mitochondrial biogenesis, the tissue-specific parameters of mitochondrial DNA maintenance have been virtually unexplored. In the presented study, we investigated mtDNA replication, topology, gene expression and damage in six different tissues of adult mice and sought to correlate these with the levels of known protein factors involved in mtDNA replication and transcription. Our results show that while liver and kidney cells replicate their mtDNA using the asynchronous mechanism known from cultured cells, tissues with high OXPHOS activity, such as heart, brain, skeletal muscle and brown fat, employ a strand-coupled replication mode, combined with increased levels of recombination. The strand-coupled replication mode correlated also with mtDNA damage levels, indicating that the replication mechanism represents a tissue-specific strategy to deal with intrinsic oxidative stress. While the preferred replication mode did not correlate with mtDNA transcription or the levels of most known mtDNA maintenance proteins, mtSSB was most abundant in tissues using strand-asynchronous mechanism. Although mitochondrial transcripts were most abundant in tissues with high metabolic rate, the mtDNA copy number per tissue mass was remarkably similar in all tissues. We propose that the tissue-specific features of mtDNA maintenance are primarily driven by the intrinsic reactive oxygen species exposure, mediated by DNA repair factors, whose identity remains to be elucidated.
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Affiliation(s)
- Elena Herbers
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI 80101, Joensuu, Finland
| | - Nina J Kekäläinen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI 80101, Joensuu, Finland
| | - Anu Hangas
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI 80101, Joensuu, Finland
| | - Jaakko L Pohjoismäki
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI 80101, Joensuu, Finland
| | - Steffi Goffart
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI 80101, Joensuu, Finland.
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27
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Shen G, Li S, Cui W, Liu S, Yang Y, Gross M, Li W. Membrane Protein Structure in Live Cells: Methodology for Studying Drug Interaction by Mass Spectrometry-Based Footprinting. Biochemistry 2017; 57:286-294. [PMID: 29192498 DOI: 10.1021/acs.biochem.7b00874] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mass spectrometry-based footprinting is an emerging approach for studying protein structure. Because integral membrane proteins are difficult targets for conventional structural biology, we recently developed a mass spectrometry (MS) footprinting method to probe membrane protein-drug interactions in live cells. This method can detect structural differences between apo and drug-bound states of membrane proteins, with the changes inferred from MS quantification of the cysteine modification pattern, generated by residue-specific chemical labeling. Here, we describe the experimental design, interpretation, advantages, and limitations of using cysteine footprinting by taking as an example the interaction of warfarin with vitamin K epoxide reductase, a human membrane protein. Compared with other structural methods, footprinting of proteins in live cells produces structural information for the near native state. Knowledge of cellular conformational states is a necessary complement to the high-resolution structures obtained from purified proteins in vitro. Thus, the MS footprinting method is broadly applicable in membrane protein biology. Future directions include probing flexible motions of membrane proteins and their interaction interface in live cells, which are often beyond the reach of conventional structural methods.
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Affiliation(s)
- Guomin Shen
- Institute of Hemostasis and Thrombosis, College of Medicine, Henan University of Science and Technology , Luoyang, Henan 471003, P. R. China.,Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine , St. Louis, Missouri 63110, United States
| | - Shuang Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine , St. Louis, Missouri 63110, United States
| | - Weidong Cui
- Department of Chemistry, Washington University , St. Louis, Missouri 63130, United States
| | - Shixuan Liu
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine , St. Louis, Missouri 63110, United States
| | - Yihu Yang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine , St. Louis, Missouri 63110, United States
| | - Michael Gross
- Department of Chemistry, Washington University , St. Louis, Missouri 63130, United States
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine , St. Louis, Missouri 63110, United States
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28
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Abstract
Eukaryotic PrimPol is a recently discovered DNA-dependent DNA primase and translesion synthesis DNA polymerase found in the nucleus and mitochondria. Although PrimPol has been shown to be required for repriming of stalled replication forks in the nucleus, its role in mitochondria has remained unresolved. Here we demonstrate in vivo and in vitro that PrimPol can reinitiate stalled mtDNA replication and can prime mtDNA replication from nonconventional origins. Our results not only help in the understanding of how mitochondria cope with replicative stress but can also explain some controversial features of the lagging-strand replication.
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29
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Guerra F, Arbini AA, Moro L. Mitochondria and cancer chemoresistance. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:686-699. [DOI: 10.1016/j.bbabio.2017.01.012] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 01/07/2023]
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30
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Pawłowska E, Szczepanska J, Blasiak J. DNA2-An Important Player in DNA Damage Response or Just Another DNA Maintenance Protein? Int J Mol Sci 2017; 18:ijms18071562. [PMID: 28718810 PMCID: PMC5536050 DOI: 10.3390/ijms18071562] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 07/13/2017] [Accepted: 07/17/2017] [Indexed: 02/01/2023] Open
Abstract
The human DNA2 (DNA replication helicase/nuclease 2) protein is expressed in both the nucleus and mitochondria, where it displays ATPase-dependent nuclease and helicase activities. DNA2 plays an important role in the removing of long flaps in DNA replication and long-patch base excision repair (LP-BER), interacting with the replication protein A (RPA) and the flap endonuclease 1 (FEN1). DNA2 can promote the restart of arrested replication fork along with Werner syndrome ATP-dependent helicase (WRN) and Bloom syndrome protein (BLM). In mitochondria, DNA2 can facilitate primer removal during strand-displacement replication. DNA2 is involved in DNA double strand (DSB) repair, in which it is complexed with BLM, RPA and MRN for DNA strand resection required for homologous recombination repair. DNA2 can be a major protein involved in the repair of complex DNA damage containing a DSB and a 5' adduct resulting from a chemical group bound to DNA 5' ends, created by ionizing radiation and several anticancer drugs, including etoposide, mitoxantrone and some anthracyclines. The role of DNA2 in telomere end maintenance and cell cycle regulation suggests its more general role in keeping genomic stability, which is impaired in cancer. Therefore DNA2 can be an attractive target in cancer therapy. This is supported by enhanced expression of DNA2 in many cancer cell lines with oncogene activation and premalignant cells. Therefore, DNA2 can be considered as a potential marker, useful in cancer therapy. DNA2, along with PARP1 inhibition, may be considered as a potential target for inducing synthetic lethality, a concept of killing tumor cells by targeting two essential genes.
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Affiliation(s)
- Elzbieta Pawłowska
- Department of Orthodontics, Medical University of Lodz, 92-216 Lodz, Poland.
| | - Joanna Szczepanska
- Department of Pediatric Dentistry, Medical University of Lodz, 92-216 Lodz, Poland.
| | - Janusz Blasiak
- Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland.
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31
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Han S, Udeshi ND, Deerinck TJ, Svinkina T, Ellisman MH, Carr SA, Ting AY. Proximity Biotinylation as a Method for Mapping Proteins Associated with mtDNA in Living Cells. Cell Chem Biol 2017; 24:404-414. [PMID: 28238724 DOI: 10.1016/j.chembiol.2017.02.002] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/21/2016] [Accepted: 01/31/2017] [Indexed: 11/27/2022]
Abstract
A recurring challenge in cell biology is to define the molecular components of macromolecular complexes of interest. The predominant method, immunoprecipitation, recovers only strong interaction partners that survive cell lysis and repeated detergent washes. We explored peroxidase-catalyzed proximity biotinylation, APEX, as an alternative, focusing on the mitochondrial nucleoid, the dynamic macromolecular complex that houses the mitochondrial genome. Via 1-min live-cell biotinylation followed by quantitative, ratiometric mass spectrometry, we enriched 37 nucleoid proteins, seven of which had never previously been associated with the nucleoid. The specificity of our dataset was very high, and we validated three hits by follow-up studies. For one novel nucleoid-associated protein, FASTKD1, we discovered a role in downregulation of mitochondrial complex I via specific repression of ND3 mRNA. Our study demonstrates that APEX is a powerful tool for mapping macromolecular complexes in living cells, and can identify proteins and pathways that have been missed by traditional approaches.
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Affiliation(s)
- Shuo Han
- Departments of Genetics, Biology, and Chemistry, Stanford University, Stanford, CA 94305, USA
| | | | - Thomas J Deerinck
- National Center for Microscopy and Imaging Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Tanya Svinkina
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Steven A Carr
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Alice Y Ting
- Departments of Genetics, Biology, and Chemistry, Stanford University, Stanford, CA 94305, USA.
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32
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El-Hattab AW, Craigen WJ, Scaglia F. Mitochondrial DNA maintenance defects. Biochim Biophys Acta Mol Basis Dis 2017; 1863:1539-1555. [PMID: 28215579 DOI: 10.1016/j.bbadis.2017.02.017] [Citation(s) in RCA: 166] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 01/31/2017] [Accepted: 02/14/2017] [Indexed: 01/12/2023]
Abstract
The maintenance of mitochondrial DNA (mtDNA) depends on a number of nuclear gene-encoded proteins including a battery of enzymes forming the replisome needed to synthesize mtDNA. These enzymes need to be in balanced quantities to function properly that is in part achieved by exchanging intramitochondrial contents through mitochondrial fusion. In addition, mtDNA synthesis requires a balanced supply of nucleotides that is achieved by nucleotide recycling inside the mitochondria and import from the cytosol. Mitochondrial DNA maintenance defects (MDMDs) are a group of diseases caused by pathogenic variants in the nuclear genes involved in mtDNA maintenance resulting in impaired mtDNA synthesis leading to quantitative (mtDNA depletion) and qualitative (multiple mtDNA deletions) defects in mtDNA. Defective mtDNA leads to organ dysfunction due to insufficient mtDNA-encoded protein synthesis, resulting in an inadequate energy production to meet the needs of affected organs. MDMDs are inherited as autosomal recessive or dominant traits, and are associated with a broad phenotypic spectrum ranging from mild adult-onset ophthalmoplegia to severe infantile fatal hepatic failure. To date, pathogenic variants in 20 nuclear genes known to be crucial for mtDNA maintenance have been linked to MDMDs, including genes encoding enzymes of mtDNA replication machinery (POLG, POLG2, TWNK, TFAM, RNASEH1, MGME1, and DNA2), genes encoding proteins that function in maintaining a balanced mitochondrial nucleotide pool (TK2, DGUOK, SUCLG1, SUCLA2, ABAT, RRM2B, TYMP, SLC25A4, AGK, and MPV17), and genes encoding proteins involved in mitochondrial fusion (OPA1, MFN2, and FBXL4).
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Affiliation(s)
- Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Pediatrics Department, Tawam Hospital, Al-Ain, United Arab Emirates
| | - William J Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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33
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Phillips AF, Millet AR, Tigano M, Dubois SM, Crimmins H, Babin L, Charpentier M, Piganeau M, Brunet E, Sfeir A. Single-Molecule Analysis of mtDNA Replication Uncovers the Basis of the Common Deletion. Mol Cell 2017; 65:527-538.e6. [PMID: 28111015 DOI: 10.1016/j.molcel.2016.12.014] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 10/04/2016] [Accepted: 12/16/2016] [Indexed: 11/30/2022]
Abstract
Mutations in mtDNA lead to muscular and neurological diseases and are linked to aging. The most frequent aberrancy is the "common deletion" that involves a 4,977-bp region flanked by 13-bp repeats. To investigate the basis of this deletion, we developed a single-molecule mtDNA combing method. The analysis of replicating mtDNA molecules provided in vivo evidence in support of the asymmetric mode of replication. Furthermore, we observed frequent fork stalling at the junction of the common deletion, suggesting that impaired replication triggers the formation of this toxic lesion. In parallel experiments, we employed mito-TALENs to induce breaks in distinct loci of the mitochondrial genome and found that breaks adjacent to the 5' repeat trigger the common deletion. Interestingly, this process was mediated by the mitochondrial replisome independent of canonical DSB repair. Altogether, our data underscore a unique replication-dependent repair pathway that leads to the mitochondrial common deletion.
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Affiliation(s)
- Aaron F Phillips
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
| | - Armêl R Millet
- Structure et Instabilité des Génomes, Muséum National d'Histoire Naturelle, INSERM U 1154, CNRS UMR 7196, 75005 Paris, France; Genome Dynamics in the Immune System Laboratory, INSERM, UMR 1163, Institut Imagine, 75015 Paris, France
| | - Marco Tigano
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
| | - Sonia M Dubois
- Structure et Instabilité des Génomes, Muséum National d'Histoire Naturelle, INSERM U 1154, CNRS UMR 7196, 75005 Paris, France
| | - Hannah Crimmins
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA
| | - Loelia Babin
- Structure et Instabilité des Génomes, Muséum National d'Histoire Naturelle, INSERM U 1154, CNRS UMR 7196, 75005 Paris, France; Genome Dynamics in the Immune System Laboratory, INSERM, UMR 1163, Institut Imagine, 75015 Paris, France
| | - Marine Charpentier
- Structure et Instabilité des Génomes, Muséum National d'Histoire Naturelle, INSERM U 1154, CNRS UMR 7196, 75005 Paris, France
| | - Marion Piganeau
- Structure et Instabilité des Génomes, Muséum National d'Histoire Naturelle, INSERM U 1154, CNRS UMR 7196, 75005 Paris, France
| | - Erika Brunet
- Structure et Instabilité des Génomes, Muséum National d'Histoire Naturelle, INSERM U 1154, CNRS UMR 7196, 75005 Paris, France; Genome Dynamics in the Immune System Laboratory, INSERM, UMR 1163, Institut Imagine, 75015 Paris, France.
| | - Agnel Sfeir
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA.
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DeBalsi KL, Hoff KE, Copeland WC. Role of the mitochondrial DNA replication machinery in mitochondrial DNA mutagenesis, aging and age-related diseases. Ageing Res Rev 2017; 33:89-104. [PMID: 27143693 DOI: 10.1016/j.arr.2016.04.006] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/19/2016] [Accepted: 04/19/2016] [Indexed: 12/19/2022]
Abstract
As regulators of bioenergetics in the cell and the primary source of endogenous reactive oxygen species (ROS), dysfunctional mitochondria have been implicated for decades in the process of aging and age-related diseases. Mitochondrial DNA (mtDNA) is replicated and repaired by nuclear-encoded mtDNA polymerase γ (Pol γ) and several other associated proteins, which compose the mtDNA replication machinery. Here, we review evidence that errors caused by this replication machinery and failure to repair these mtDNA errors results in mtDNA mutations. Clonal expansion of mtDNA mutations results in mitochondrial dysfunction, such as decreased electron transport chain (ETC) enzyme activity and impaired cellular respiration. We address the literature that mitochondrial dysfunction, in conjunction with altered mitochondrial dynamics, is a major driving force behind aging and age-related diseases. Additionally, interventions to improve mitochondrial function and attenuate the symptoms of aging are examined.
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Affiliation(s)
- Karen L DeBalsi
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Kirsten E Hoff
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - William C Copeland
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
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35
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Shen G, Cui W, Zhang H, Zhou F, Huang W, Liu Q, Yang Y, Li S, Bowman GR, Sadler JE, Gross ML, Li W. Warfarin traps human vitamin K epoxide reductase in an intermediate state during electron transfer. Nat Struct Mol Biol 2016; 24:69-76. [PMID: 27918545 DOI: 10.1038/nsmb.3333] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 10/24/2016] [Indexed: 01/25/2023]
Abstract
Although warfarin is the most widely used anticoagulant worldwide, the mechanism by which warfarin inhibits its target, human vitamin K epoxide reductase (hVKOR), remains unclear. Here we show that warfarin blocks a dynamic electron-transfer process in hVKOR. A major fraction of cellular hVKOR is in an intermediate redox state containing a Cys51-Cys132 disulfide, a characteristic accommodated by a four-transmembrane-helix structure of hVKOR. Warfarin selectively inhibits this major cellular form of hVKOR, whereas disruption of the Cys51-Cys132 disulfide impairs warfarin binding and causes warfarin resistance. Relying on binding interactions identified by cysteine alkylation footprinting and mass spectrometry coupled with mutagenesis analysis, we conducted structure simulations, which revealed a closed warfarin-binding pocket stabilized by the Cys51-Cys132 linkage. Understanding the selective warfarin inhibition of a specific redox state of hVKOR should enable the rational design of drugs that exploit the redox chemistry and associated conformational changes in hVKOR.
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Affiliation(s)
- Guomin Shen
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Weidong Cui
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Hao Zhang
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Fengbo Zhou
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Wei Huang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA.,School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Qian Liu
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Forensic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yihu Yang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Shuang Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Gregory R Bowman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - J Evan Sadler
- Division of Hematology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
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36
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Lewis SC, Uchiyama LF, Nunnari J. ER-mitochondria contacts couple mtDNA synthesis with mitochondrial division in human cells. Science 2016; 353:aaf5549. [PMID: 27418514 DOI: 10.1126/science.aaf5549] [Citation(s) in RCA: 402] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/26/2016] [Indexed: 12/17/2022]
Abstract
Mitochondrial DNA (mtDNA) encodes RNAs and proteins critical for cell function. In human cells, hundreds to thousands of mtDNA copies are replicated asynchronously, packaged into protein-DNA nucleoids, and distributed within a dynamic mitochondrial network. The mechanisms that govern how nucleoids are chosen for replication and distribution are not understood. Mitochondrial distribution depends on division, which occurs at endoplasmic reticulum (ER)-mitochondria contact sites. These sites were spatially linked to a subset of nucleoids selectively marked by mtDNA polymerase and engaged in mtDNA synthesis--events that occurred upstream of mitochondrial constriction and division machine assembly. Our data suggest that ER tubules proximal to nucleoids are necessary but not sufficient for mtDNA synthesis. Thus, ER-mitochondria contacts coordinate licensing of mtDNA synthesis with division to distribute newly replicated nucleoids to daughter mitochondria.
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Affiliation(s)
- Samantha C Lewis
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Lauren F Uchiyama
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Jodi Nunnari
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA.
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37
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Abstract
Recent advances in the field of mitochondrial DNA (mtDNA) replication highlight the diversity of both the mechanisms utilized and the structural and functional organization of the proteins at mtDNA replication fork, despite the relative simplicity of the animal mtDNA genome. DNA polymerase γ, mtDNA helicase and mitochondrial single-stranded DNA-binding protein-the key replisome proteins, have evolved distinct structural features and biochemical properties. These appear to be correlated with mtDNA genomic features in different metazoan taxa and with their modes of DNA replication, although substantial integrative research is warranted to establish firmly these links. To date, several modes of mtDNA replication have been described for animals: rolling circle, theta, strand-displacement, and RITOLS/bootlace. Resolution of a continuing controversy relevant to mtDNA replication in mammals/vertebrates will have a direct impact on the mechanistic interpretation of mtDNA-related human diseases. Here we review these subjects, integrating earlier and recent data to provide a perspective on the major challenges for future research.
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Affiliation(s)
- G L Ciesielski
- Institute of Biosciences and Medical Technology, University of Tampere, Tampere, Finland; Michigan State University, East Lansing, MI, United States
| | - M T Oliveira
- Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista "Júlio de Mesquita Filho", Jaboticabal, SP, Brazil
| | - L S Kaguni
- Institute of Biosciences and Medical Technology, University of Tampere, Tampere, Finland; Michigan State University, East Lansing, MI, United States.
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38
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Young MJ, Copeland WC. Human mitochondrial DNA replication machinery and disease. Curr Opin Genet Dev 2016; 38:52-62. [PMID: 27065468 DOI: 10.1016/j.gde.2016.03.005] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/03/2016] [Accepted: 03/08/2016] [Indexed: 12/21/2022]
Abstract
The human mitochondrial genome is replicated by DNA polymerase γ in concert with key components of the mitochondrial DNA (mtDNA) replication machinery. Defects in mtDNA replication or nucleotide metabolism cause deletions, point mutations, or depletion of mtDNA. The resulting loss of cellular respiration ultimately induces mitochondrial genetic diseases, including mtDNA depletion syndromes (MDS) such as Alpers or early infantile hepatocerebral syndromes, and mtDNA deletion disorders such as progressive external ophthalmoplegia, ataxia-neuropathy, or mitochondrial neurogastrointestinal encephalomyopathy. Here we review the current literature regarding human mtDNA replication and heritable disorders caused by genetic changes of the POLG, POLG2, Twinkle, RNASEH1, DNA2, and MGME1 genes.
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Affiliation(s)
- Matthew J Young
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC 27709, United States
| | - William C Copeland
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC 27709, United States.
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39
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Felhi R, Mkaouar-Rebai E, Sfaihi-Ben Mansour L, Alila-Fersi O, Tabebi M, Ben Rhouma B, Ammar M, Keskes L, Hachicha M, Fakhfakh F. Mutational analysis in patients with neuromuscular disorders: Detection of mitochondrial deletion and double mutations in the MT-ATP6 gene. Biochem Biophys Res Commun 2016; 473:61-66. [PMID: 26993169 DOI: 10.1016/j.bbrc.2016.03.050] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 03/13/2016] [Indexed: 12/16/2022]
Abstract
Mitochondrial diseases encompass a wide variety of pathologies characterized by a dysfunction of the mitochondrial respiratory chain resulting in an energy deficiency. The respiratory chain consists of five multi-protein complexes providing coupling between nutrient oxidation and phosphorylation of ADP to ATP. In the present report, we studied mitochondrial genes of complex I, III, IV and V in 2 Tunisian patients with mitochondrial neuromuscular disorders. In the first patient, we detected the m.8392C>T variation (P136S) in the mitochondrial ATPase6 gene and the m.8527A>G transition at the junction MT-ATP6/MT-ATP8 which change the initiation codon AUG to GUG. The presence of these two variations in such an important gene could probably affect the ATP synthesis in the studied patient. In the second patient, we detected several known variations in addition to a mitochondrial deletion in the major arc of the mtDNA eliminating tRNA and respiratory chain protein genes. This deletion could be responsible of an inefficient translation leading to an inefficient mitochondrial protein synthesis in P2.
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Affiliation(s)
- Rahma Felhi
- Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine de Sfax, Université de Sfax, Tunisia
| | - Emna Mkaouar-Rebai
- Département des Sciences de la Vie, Faculté des Sciences de Sfax, Université de Sfax, Tunisia.
| | | | - Olfa Alila-Fersi
- Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine de Sfax, Université de Sfax, Tunisia
| | - Mouna Tabebi
- Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine de Sfax, Université de Sfax, Tunisia
| | - Bochra Ben Rhouma
- Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine de Sfax, Université de Sfax, Tunisia
| | - Marwa Ammar
- Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine de Sfax, Université de Sfax, Tunisia
| | - Leila Keskes
- Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine de Sfax, Université de Sfax, Tunisia
| | | | - Faiza Fakhfakh
- Département des Sciences de la Vie, Faculté des Sciences de Sfax, Université de Sfax, Tunisia
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40
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Sen D, Patel G, Patel SS. Homologous DNA strand exchange activity of the human mitochondrial DNA helicase TWINKLE. Nucleic Acids Res 2016; 44:4200-10. [PMID: 26887820 PMCID: PMC4872091 DOI: 10.1093/nar/gkw098] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/08/2016] [Indexed: 01/03/2023] Open
Abstract
A crucial component of the human mitochondrial DNA replisome is the ring-shaped helicase TWINKLE-a phage T7-gene 4-like protein expressed in the nucleus and localized in the human mitochondria. Our previous studies showed that despite being a helicase, TWINKLE has unique DNA annealing activity. At the time, the implications of DNA annealing by TWINKLE were unclear. Herein, we report that TWINKLE uses DNA annealing function to actively catalyze strand-exchange reaction between the unwinding substrate and a homologous single-stranded DNA. Using various biochemical experiments, we demonstrate that the mechanism of strand-exchange involves active coupling of unwinding and annealing reactions by the TWINKLE. Unlike strand-annealing, the strand-exchange reaction requires nucleotide hydrolysis and greatly stimulated by short region of homology between the recombining DNA strands that promote joint molecule formation to initiate strand-exchange. Furthermore, we show that TWINKLE catalyzes branch migration by resolving homologous four-way junction DNA. These four DNA modifying activities of TWINKLE: strand-separation, strand-annealing, strand-exchange and branch migration suggest a dual role of TWINKLE in mitochondrial DNA maintenance. In addition to playing a major role in fork progression during leading strand DNA synthesis, we propose that TWINKLE is involved in recombinational repair of the human mitochondrial DNA.
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Affiliation(s)
- Doyel Sen
- Rutgers University, Robert Wood Johnson Medical School, Department of Biochemistry and Molecular Biology, NJ 08854, USA
| | - Gayatri Patel
- Rutgers University, Robert Wood Johnson Medical School, Department of Biochemistry and Molecular Biology, NJ 08854, USA
| | - Smita S Patel
- Rutgers University, Robert Wood Johnson Medical School, Department of Biochemistry and Molecular Biology, NJ 08854, USA
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41
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Analysis of Replicating Mitochondrial DNA by In Organello Labeling and Two-Dimensional Agarose Gel Electrophoresis. Methods Mol Biol 2016; 1351:95-113. [PMID: 26530677 DOI: 10.1007/978-1-4939-3040-1_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Our understanding of the mechanisms of DNA replication in a broad range of organisms and viruses has benefited from the application of two-dimensional agarose gel electrophoresis (2D-AGE). The method resolves DNA molecules on the basis of size and shape and is technically straightforward. 2D-AGE sparked controversy in the field of mitochondria when it revealed replicating molecules with lengthy tracts of RNA, a phenomenon never before reported in nature. More recently, radioisotope labeling of the DNA in the mitochondria has been coupled with 2D-AGE. In its first application, this procedure helped to delineate the "bootlace mechanism of mitochondrial DNA replication," in which processed mitochondrial transcripts are hybridized to the lagging strand template at the replication fork as the leading DNA strand is synthesized. This chapter provides details of the method, how it has been applied to date and concludes with some potential future applications of the technique.
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42
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Martínez-Reyes I, Diebold LP, Kong H, Schieber M, Huang H, Hensley CT, Mehta MM, Wang T, Santos JH, Woychik R, Dufour E, Spelbrink JN, Weinberg SE, Zhao Y, DeBerardinis RJ, Chandel NS. TCA Cycle and Mitochondrial Membrane Potential Are Necessary for Diverse Biological Functions. Mol Cell 2015; 61:199-209. [PMID: 26725009 DOI: 10.1016/j.molcel.2015.12.002] [Citation(s) in RCA: 343] [Impact Index Per Article: 38.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 10/19/2015] [Accepted: 11/17/2015] [Indexed: 12/24/2022]
Abstract
Mitochondrial metabolism is necessary for the maintenance of oxidative TCA cycle function and mitochondrial membrane potential. Previous attempts to decipher whether mitochondria are necessary for biological outcomes have been hampered by genetic and pharmacologic methods that simultaneously disrupt multiple functions linked to mitochondrial metabolism. Here, we report that inducible depletion of mitochondrial DNA (ρ(ο) cells) diminished respiration, oxidative TCA cycle function, and the mitochondrial membrane potential, resulting in diminished cell proliferation, hypoxic activation of HIF-1, and specific histone acetylation marks. Genetic reconstitution only of the oxidative TCA cycle function specifically in these inducible ρ(ο) cells restored metabolites, resulting in re-establishment of histone acetylation. In contrast, genetic reconstitution of the mitochondrial membrane potential restored ROS, which were necessary for hypoxic activation of HIF-1 and cell proliferation. These results indicate that distinct mitochondrial functions associated with respiration are necessary for cell proliferation, epigenetics, and HIF-1 activation.
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Affiliation(s)
| | - Lauren P Diebold
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Hyewon Kong
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Michael Schieber
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - He Huang
- Ben May Department of Cancer Research, The University of Chicago, Chicago, IL 60637, USA
| | - Christopher T Hensley
- Children Medical Center Research Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Manan M Mehta
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Tianyuan Wang
- Division of Extramural Research and Training, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC 27709, USA
| | - Janine H Santos
- Division of Extramural Research and Training, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC 27709, USA
| | - Richard Woychik
- Division of Extramural Research and Training, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC 27709, USA
| | - Eric Dufour
- BioMediTech and Tampere University Hospital, University of Tampere, Biokatu 8, 33520 Tampere, Finland
| | - Johannes N Spelbrink
- Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, Radboud University Medical Centre, Geert Grooteplein 10, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Samuel E Weinberg
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Yingming Zhao
- Ben May Department of Cancer Research, The University of Chicago, Chicago, IL 60637, USA
| | - Ralph J DeBerardinis
- Children Medical Center Research Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Navdeep S Chandel
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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43
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Kaguni LS, Oliveira MT. Structure, function and evolution of the animal mitochondrial replicative DNA helicase. Crit Rev Biochem Mol Biol 2015; 51:53-64. [PMID: 26615986 DOI: 10.3109/10409238.2015.1117056] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The mitochondrial replicative DNA helicase is essential for animal mitochondrial DNA (mtDNA) maintenance. Deleterious mutations in the gene that encodes it cause mitochondrial dysfunction manifested in developmental delays, defects and arrest, limited life span, and a number of human pathogenic phenotypes that are recapitulated in animals across taxa. In fact, the replicative mtDNA helicase was discovered with the identification of human disease mutations in its nuclear gene, and based upon its deduced amino acid sequence homology with bacteriophage T7 gene 4 protein (T7 gp4), a bi-functional primase-helicase. Since that time, numerous investigations of its structure, mechanism, and physiological relevance have been reported, and human disease alleles have been modeled in the human, mouse, and Drosophila systems. Here, we review this literature and draw evolutionary comparisons that serve to shed light on its divergent features.
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Affiliation(s)
- Laurie S Kaguni
- a Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine , Michigan State University , East Lansing , MI , USA .,b Institute of Biosciences and Medical Technology, University of Tampere , Tampere , Finland , and
| | - Marcos T Oliveira
- c Departamento de Tecnologia , Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista "Júlio de Mesquita Filho" , Jaboticabal , Brazil
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Torregrosa-Muñumer R, Goffart S, Haikonen JA, Pohjoismäki JLO. Low doses of ultraviolet radiation and oxidative damage induce dramatic accumulation of mitochondrial DNA replication intermediates, fork regression, and replication initiation shift. Mol Biol Cell 2015; 26:4197-208. [PMID: 26399294 PMCID: PMC4642854 DOI: 10.1091/mbc.e15-06-0390] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/14/2015] [Indexed: 12/14/2022] Open
Abstract
Oxidative damage is believed to cause pathological mitochondrial DNA (mtDNA) rearrangements. mtDNA damage induces specific changes in its maintenance, such as formation of x-junctions and changes in replication mode. The findings explain the significance of the different replication mechanisms that have been observed in mitochondria. Mitochondrial DNA is prone to damage by various intrinsic as well as environmental stressors. DNA damage can in turn cause problems for replication, resulting in replication stalling and double-strand breaks, which are suspected to be the leading cause of pathological mtDNA rearrangements. In this study, we exposed cells to subtle levels of oxidative stress or UV radiation and followed their effects on mtDNA maintenance. Although the damage did not influence mtDNA copy number, we detected a massive accumulation of RNA:DNA hybrid–containing replication intermediates, followed by an increase in cruciform DNA molecules, as well as in bidirectional replication initiation outside of the main replication origin, OH. Our results suggest that mitochondria maintain two different types of replication as an adaptation to different cellular environments; the RNA:DNA hybrid–involving replication mode maintains mtDNA integrity in tissues with low oxidative stress, and the potentially more error tolerant conventional strand-coupled replication operates when stress is high.
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Affiliation(s)
| | - Steffi Goffart
- Department of Biology, University of Eastern Finland, 80101 Joensuu, Finland
| | - Juha A Haikonen
- Department of Biology, University of Eastern Finland, 80101 Joensuu, Finland
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Akhmedov AT, Marín-García J. Mitochondrial DNA maintenance: an appraisal. Mol Cell Biochem 2015; 409:283-305. [DOI: 10.1007/s11010-015-2532-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/06/2015] [Indexed: 12/13/2022]
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46
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Reyes A, Melchionda L, Nasca A, Carrara F, Lamantea E, Zanolini A, Lamperti C, Fang M, Zhang J, Ronchi D, Bonato S, Fagiolari G, Moggio M, Ghezzi D, Zeviani M. RNASEH1 Mutations Impair mtDNA Replication and Cause Adult-Onset Mitochondrial Encephalomyopathy. Am J Hum Genet 2015; 97:186-93. [PMID: 26094573 DOI: 10.1016/j.ajhg.2015.05.013] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 05/21/2015] [Indexed: 11/27/2022] Open
Abstract
Chronic progressive external ophthalmoplegia (CPEO) is common in mitochondrial disorders and is frequently associated with multiple mtDNA deletions. The onset is typically in adulthood, and affected subjects can also present with general muscle weakness. The underlying genetic defects comprise autosomal-dominant or recessive mutations in several nuclear genes, most of which play a role in mtDNA replication. Next-generation sequencing led to the identification of compound-heterozygous RNASEH1 mutations in two singleton subjects and a homozygous mutation in four siblings. RNASEH1, encoding ribonuclease H1 (RNase H1), is an endonuclease that is present in both the nucleus and mitochondria and digests the RNA component of RNA-DNA hybrids. Unlike mitochondria, the nucleus harbors a second ribonuclease (RNase H2). All affected individuals first presented with CPEO and exercise intolerance in their twenties, and these were followed by muscle weakness, dysphagia, and spino-cerebellar signs with impaired gait coordination, dysmetria, and dysarthria. Ragged-red and cytochrome c oxidase (COX)-negative fibers, together with impaired activity of various mitochondrial respiratory chain complexes, were observed in muscle biopsies of affected subjects. Western blot analysis showed the virtual absence of RNase H1 in total lysate from mutant fibroblasts. By an in vitro assay, we demonstrated that altered RNase H1 has a reduced capability to remove the RNA from RNA-DNA hybrids, confirming their pathogenic role. Given that an increasing amount of evidence indicates the presence of RNA primers during mtDNA replication, this result might also explain the accumulation of mtDNA deletions and underscores the importance of RNase H1 for mtDNA maintenance.
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Affiliation(s)
- Aurelio Reyes
- Mitochondrial Biology Unit, Medical Research Council, Cambridge CB2 0XY, UK
| | - Laura Melchionda
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20126, Italy
| | - Alessia Nasca
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20126, Italy
| | - Franco Carrara
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20126, Italy
| | - Eleonora Lamantea
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20126, Italy
| | - Alice Zanolini
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20126, Italy
| | - Costanza Lamperti
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20126, Italy
| | - Mingyan Fang
- Beijing Genomic Institute, Shenzhen 518083, China
| | | | - Dario Ronchi
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Center, IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan 20122, Italy
| | - Sara Bonato
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Center, IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan 20122, Italy
| | - Gigliola Fagiolari
- Neuromuscular Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Center, IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan 20122, Italy
| | - Maurizio Moggio
- Neuromuscular Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Center, IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan 20122, Italy
| | - Daniele Ghezzi
- Unit of Molecular Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20126, Italy.
| | - Massimo Zeviani
- Mitochondrial Biology Unit, Medical Research Council, Cambridge CB2 0XY, UK.
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Fernández-Millán P, Lázaro M, Cansız-Arda Ş, Gerhold JM, Rajala N, Schmitz CA, Silva-Espiña C, Gil D, Bernadó P, Valle M, Spelbrink JN, Solà M. The hexameric structure of the human mitochondrial replicative helicase Twinkle. Nucleic Acids Res 2015; 43:4284-95. [PMID: 25824949 PMCID: PMC4417153 DOI: 10.1093/nar/gkv189] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 12/21/2014] [Accepted: 02/23/2015] [Indexed: 01/28/2023] Open
Abstract
The mitochondrial replicative helicase Twinkle is involved in strand separation at the replication fork of mitochondrial DNA (mtDNA). Twinkle malfunction is associated with rare diseases that include late onset mitochondrial myopathies, neuromuscular disorders and fatal infantile mtDNA depletion syndrome. We examined its 3D structure by electron microscopy (EM) and small angle X-ray scattering (SAXS) and built the corresponding atomic models, which gave insight into the first molecular architecture of a full-length SF4 helicase that includes an N-terminal zinc-binding domain (ZBD), an intermediate RNA polymerase domain (RPD) and a RecA-like hexamerization C-terminal domain (CTD). The EM model of Twinkle reveals a hexameric two-layered ring comprising the ZBDs and RPDs in one layer and the CTDs in another. In the hexamer, contacts in trans with adjacent subunits occur between ZBDs and RPDs, and between RPDs and CTDs. The ZBDs show important structural heterogeneity. In solution, the scattering data are compatible with a mixture of extended hexa- and heptameric models in variable conformations. Overall, our structural data show a complex network of dynamic interactions that reconciles with the structural flexibility required for helicase activity.
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Affiliation(s)
- Pablo Fernández-Millán
- Structural MitoLab; Department of Structural Biology, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona, E-08028, Spain
| | - Melisa Lázaro
- Structural Biology Unit. Centre for Cooperative Research in Biosciences, CICbioGUNE, Derio, E-48160, Spain
| | - Şirin Cansız-Arda
- Department of Pediatrics, Nijmegen Centre for Mitochondrial Disorders, Radboud University Medical Centre, Nijmegen, 6525 GA, The Netherlands
| | - Joachim M Gerhold
- Department of Pediatrics, Nijmegen Centre for Mitochondrial Disorders, Radboud University Medical Centre, Nijmegen, 6525 GA, The Netherlands
| | - Nina Rajala
- Mitochondrial DNA Maintenance Group, BioMediTech, University of Tampere, Tampere, FI-33014, Finland
| | - Claus-A Schmitz
- Structural MitoLab; Department of Structural Biology, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona, E-08028, Spain
| | - Cristina Silva-Espiña
- Structural MitoLab; Department of Structural Biology, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona, E-08028, Spain
| | - David Gil
- Structural Biology Unit. Centre for Cooperative Research in Biosciences, CICbioGUNE, Derio, E-48160, Spain
| | - Pau Bernadó
- Centre de Biochimie Structurale, INSERM-U1054, CNRS UMR-5048, Université de Montpellier I&II. Montpellier, F-34090, France
| | - Mikel Valle
- Structural Biology Unit. Centre for Cooperative Research in Biosciences, CICbioGUNE, Derio, E-48160, Spain
| | - Johannes N Spelbrink
- Department of Pediatrics, Nijmegen Centre for Mitochondrial Disorders, Radboud University Medical Centre, Nijmegen, 6525 GA, The Netherlands Mitochondrial DNA Maintenance Group, BioMediTech, University of Tampere, Tampere, FI-33014, Finland
| | - Maria Solà
- Structural MitoLab; Department of Structural Biology, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona, E-08028, Spain
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48
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Tesori V, Piscaglia AC, Samengo D, Barba M, Bernardini C, Scatena R, Pontoglio A, Castellini L, Spelbrink JN, Maulucci G, Puglisi MA, Pani G, Gasbarrini A. The multikinase inhibitor Sorafenib enhances glycolysis and synergizes with glycolysis blockade for cancer cell killing. Sci Rep 2015; 5:9149. [PMID: 25779766 PMCID: PMC4361992 DOI: 10.1038/srep09149] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 02/20/2015] [Indexed: 12/20/2022] Open
Abstract
Although the only effective drug against primary hepatocarcinoma, the multikinase inhibitor Sorafenib (SFB) usually fails to eradicate liver cancer. Since SFB targets mitochondria, cell metabolic reprogramming may underlie intrinsic tumor resistance. To characterize cancer cell metabolic response to SFB, we measured oxygen consumption, generation of reactive oxygen species (ROS) and ATP content in rat LCSC (Liver Cancer Stem Cells) -2 cells exposed to the drug. Genome wide analysis of gene expression was performed by Affymetrix technology. SFB cytotoxicity was evaluated by multiple assays in the presence or absence of metabolic inhibitors, or in cells genetically depleted of mitochondria. We found that low concentrations (2.5-5 μM) of SFB had a relatively modest effect on LCSC-2 or 293 T cell growth, but damaged mitochondria and increased intracellular ROS. Gene expression profiling of SFB-treated cells was consistent with a shift toward aerobic glycolysis and, accordingly, SFB cytotoxicity was dramatically increased by glucose withdrawal or the glycolytic inhibitor 2-DG. Under metabolic stress, activation of the AMP dependent Protein Kinase (AMPK), but not ROS blockade, protected cells from death. We conclude that mitochondrial damage and ROS drive cell killing by SFB, while glycolytic cell reprogramming may represent a resistance strategy potentially targetable by combination therapies.
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Affiliation(s)
- Valentina Tesori
- Institute of Internal Medicine and Gastroenterology, Catholic University of the Sacred Heart School of Medicine
| | - Anna Chiara Piscaglia
- Institute of Internal Medicine and Gastroenterology, Catholic University of the Sacred Heart School of Medicine
| | - Daniela Samengo
- Institute of General Pathology, Laboratory of Cell Signaling, Catholic University of the Sacred Heart School of Medicine
| | - Marta Barba
- Institute of Human Anatomy and Cell Biology, Catholic University of the Sacred Heart School of Medicine
| | - Camilla Bernardini
- Institute of Human Anatomy and Cell Biology, Catholic University of the Sacred Heart School of Medicine
| | - Roberto Scatena
- Institute of Biochemistry and Clinical Biochemistry, Catholic University of the sacred Heart School of Medicine
| | - Alessandro Pontoglio
- Institute of Biochemistry and Clinical Biochemistry, Catholic University of the sacred Heart School of Medicine
| | - Laura Castellini
- Department of Radiation Oncology, Center for Clinical Sciences Research, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Johannes N Spelbrink
- Department of Pediatrics, Nijmegen Centre for Mitochondrial Disorders, Radboud University Medical Centre, Geert Grooteplein 10, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Institute of Biomedical Technology &Tampere University Hospital, Pirkanmaa Hospital District, University of Tampere, FI-33014, Finland
| | - Giuseppe Maulucci
- Institute of Physics, Catholic University of the Sacred Heart School of Medicine
| | - Maria Ausiliatrice Puglisi
- Institute of Internal Medicine and Gastroenterology, Catholic University of the Sacred Heart School of Medicine
| | - Giovambattista Pani
- Institute of General Pathology, Laboratory of Cell Signaling, Catholic University of the Sacred Heart School of Medicine
| | - Antonio Gasbarrini
- Institute of Internal Medicine and Gastroenterology, Catholic University of the Sacred Heart School of Medicine
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49
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Rajala N, Hensen F, Wessels HJCT, Ives D, Gloerich J, Spelbrink JN. Whole cell formaldehyde cross-linking simplifies purification of mitochondrial nucleoids and associated proteins involved in mitochondrial gene expression. PLoS One 2015; 10:e0116726. [PMID: 25695250 PMCID: PMC4335056 DOI: 10.1371/journal.pone.0116726] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 12/13/2014] [Indexed: 11/19/2022] Open
Abstract
Mitochondrial DNA/protein complexes (nucleoids) appear as discrete entities inside the mitochondrial network when observed by live-cell imaging and immunofluorescence. This somewhat trivial observation in recent years has spurred research towards isolation of these complexes and the identification of nucleoid-associated proteins. Here we show that whole cell formaldehyde crosslinking combined with affinity purification and tandem mass-spectrometry provides a simple and reproducible method to identify potential nucleoid associated proteins. The method avoids spurious mitochondrial isolation and subsequent multifarious nucleoid enrichment protocols and can be implemented to allow for label-free quantification (LFQ) by mass-spectrometry. Using expression of a Flag-tagged Twinkle helicase and appropriate controls we show that this method identifies many previously identified nucleoid associated proteins. Using LFQ to compare HEK293 cells with and without mtDNA, but both expressing Twinkle-FLAG, identifies many proteins that are reduced or absent in the absence of mtDNA. This set not only includes established mtDNA maintenance proteins but also many proteins involved in mitochondrial RNA metabolism and translation and therefore represents what can be considered an mtDNA gene expression proteome. Our data provides a very valuable resource for both basic mitochondrial researchers as well as clinical geneticists working to identify novel disease genes on the basis of exome sequence data.
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Affiliation(s)
- Nina Rajala
- Mitochondrial DNA Maintenance Group, BioMediTech, FI-33014 University of Tampere, Tampere, Finland
| | - Fenna Hensen
- Department of Pediatrics, Nijmegen Centre for Mitochondrial Disorders, Radboud University Medical Centre, Geert Grooteplein 10, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Hans J. C. T. Wessels
- Department of Pediatrics, Nijmegen Centre for Mitochondrial Disorders, Radboud University Medical Centre, Geert Grooteplein 10, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
- Radboud Proteomics Centre, Department of Laboratory Medicine, Laboratory of Genetic Endocrine and Metabolic Disorders, Radboud University Medical Centre, Geert Grooteplein 10, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Daniel Ives
- MRC-National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Jolein Gloerich
- Department of Pediatrics, Nijmegen Centre for Mitochondrial Disorders, Radboud University Medical Centre, Geert Grooteplein 10, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
- Radboud Proteomics Centre, Department of Laboratory Medicine, Laboratory of Genetic Endocrine and Metabolic Disorders, Radboud University Medical Centre, Geert Grooteplein 10, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Johannes N. Spelbrink
- Mitochondrial DNA Maintenance Group, BioMediTech, FI-33014 University of Tampere, Tampere, Finland
- Department of Pediatrics, Nijmegen Centre for Mitochondrial Disorders, Radboud University Medical Centre, Geert Grooteplein 10, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
- * E-mail:
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50
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Singh HR, Ladurner AG, Kong H, Schieber M, Huang H, Hensley CT, Mehta MM, Wang T, Santos JH, Woychik R, Dufour E, Spelbrink JN, Weinberg SE, Zhao Y, DeBerardinis RJ, Chandel NS. ACF takes the driver's seat. Mol Cell 2014. [PMID: 25105485 DOI: 10.1016/j.molcel] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
ISWI family chromatin remodeling enzymes generate regularly spaced nucleosome arrays. In a recent Nature report, Hwang et al. (2014) describe how ACF gauges the length of linker DNA when deciding to accelerate nucleosome sliding or to put on the brakes.
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Affiliation(s)
- Hari R Singh
- Department of Physiological Chemistry, Butenandt Institute and LMU Biomedical Center, Ludwig-Maximilians-University of Munich, Butenandtstrasse 5, 81377 Munich, Germany
| | - Andreas G Ladurner
- Department of Physiological Chemistry, Butenandt Institute and LMU Biomedical Center, Ludwig-Maximilians-University of Munich, Butenandtstrasse 5, 81377 Munich, Germany; International Max Planck Research School for Molecular and Cellular Life Sciences, Am Klopferspitz 18, 82152 Martinsried, Germany; Center for Integrated Protein Science Munich (CIPSM), 81377 Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), 80336 Munich, Germany.
| | - Hyewon Kong
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Michael Schieber
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - He Huang
- Ben May Department of Cancer Research, The University of Chicago, Chicago, IL 60637, USA
| | - Christopher T Hensley
- Children Medical Center Research Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Manan M Mehta
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Tianyuan Wang
- Division of Extramural Research and Training, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC 27709, USA
| | - Janine H Santos
- Division of Extramural Research and Training, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC 27709, USA
| | - Richard Woychik
- Division of Extramural Research and Training, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, NC 27709, USA
| | - Eric Dufour
- BioMediTech and Tampere University Hospital, University of Tampere, Biokatu 8, 33520 Tampere, Finland
| | - Johannes N Spelbrink
- Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, Radboud University Medical Centre, Geert Grooteplein 10, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Samuel E Weinberg
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Yingming Zhao
- Ben May Department of Cancer Research, The University of Chicago, Chicago, IL 60637, USA
| | - Ralph J DeBerardinis
- Children Medical Center Research Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Navdeep S Chandel
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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