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Wu H, Zhang W, Xu F, Peng K, Liu X, Ding W, Ma Q, Cheng H, Wang X. C17orf80 binds the mitochondrial genome to promote its replication. J Cell Biol 2023; 222:e202302037. [PMID: 37676315 PMCID: PMC10484793 DOI: 10.1083/jcb.202302037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 06/26/2023] [Accepted: 07/17/2023] [Indexed: 09/08/2023] Open
Abstract
Serving as the power plant and signaling hub of a cell, mitochondria contain their own genome which encodes proteins essential for energy metabolism and forms DNA-protein assemblies called nucleoids. Mitochondrial DNA (mtDNA) exists in multiple copies within each cell ranging from hundreds to tens of thousands. Maintaining mtDNA homeostasis is vital for healthy cells, and its dysregulation causes multiple human diseases. However, the players involved in regulating mtDNA maintenance are largely unknown though the core components of its replication machinery have been characterized. Here, we identify C17orf80, a functionally uncharacterized protein, as a critical player in maintaining mtDNA homeostasis. C17orf80 primarily localizes to mitochondrial nucleoid foci and exhibits robust double-stranded DNA binding activity throughout the mitochondrial genome, thus constituting a bona fide new mitochondrial nucleoid protein. It controls mtDNA levels by promoting mtDNA replication and plays important roles in mitochondrial metabolism and cell proliferation. Our findings provide a potential target for therapeutics of human diseases associated with defective mtDNA control.
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Affiliation(s)
- Hao Wu
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
- Academy of Advanced Interdisciplinary Study, Peking University, Beijing, China
| | - Wenshuo Zhang
- Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing, China
| | - Fengli Xu
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Kun Peng
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Xiaoyu Liu
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Wanqiu Ding
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Qi Ma
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Heping Cheng
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
- Research Unit of Mitochondria in Brain Diseases, Chinese Academy of Medical Sciences, PKU-Nanjing Institute of Translational Medicine, Nanjing, China
| | - Xianhua Wang
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
- Research Unit of Mitochondria in Brain Diseases, Chinese Academy of Medical Sciences, PKU-Nanjing Institute of Translational Medicine, Nanjing, China
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2
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González-Arzola K, Díaz-Quintana A. Mitochondrial Factors in the Cell Nucleus. Int J Mol Sci 2023; 24:13656. [PMID: 37686461 PMCID: PMC10563088 DOI: 10.3390/ijms241713656] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/31/2023] [Accepted: 08/31/2023] [Indexed: 09/10/2023] Open
Abstract
The origin of eukaryotic organisms involved the integration of mitochondria into the ancestor cell, with a massive gene transfer from the original proteobacterium to the host nucleus. Thus, mitochondrial performance relies on a mosaic of nuclear gene products from a variety of genomes. The concerted regulation of their synthesis is necessary for metabolic housekeeping and stress response. This governance involves crosstalk between mitochondrial, cytoplasmic, and nuclear factors. While anterograde and retrograde regulation preserve mitochondrial homeostasis, the mitochondria can modulate a wide set of nuclear genes in response to an extensive variety of conditions, whose response mechanisms often merge. In this review, we summarise how mitochondrial metabolites and proteins-encoded either in the nucleus or in the organelle-target the cell nucleus and exert different actions modulating gene expression and the chromatin state, or even causing DNA fragmentation in response to common stress conditions, such as hypoxia, oxidative stress, unfolded protein stress, and DNA damage.
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Affiliation(s)
- Katiuska González-Arzola
- Centro Andaluz de Biología Molecular y Medicina Regenerativa—CABIMER, Consejo Superior de Investigaciones Científicas—Universidad de Sevilla—Universidad Pablo de Olavide, 41092 Seville, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Universidad de Sevilla, 41012 Seville, Spain
| | - Antonio Díaz-Quintana
- Departamento de Bioquímica Vegetal y Biología Molecular, Universidad de Sevilla, 41012 Seville, Spain
- Instituto de Investigaciones Químicas—cicCartuja, Universidad de Sevilla—C.S.I.C, 41092 Seville, Spain
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3
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Xian H, Karin M. Oxidized mitochondrial DNA: a protective signal gone awry. Trends Immunol 2023; 44:188-200. [PMID: 36739208 DOI: 10.1016/j.it.2023.01.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/10/2023] [Accepted: 01/13/2023] [Indexed: 02/05/2023]
Abstract
Despite the emergence of mitochondria as key regulators of innate immunity, the mechanisms underlying the generation and release of immunostimulatory alarmins by stressed mitochondria remains nebulous. We propose that the major mitochondrial alarmin in myeloid cells is oxidized mitochondrial DNA (Ox-mtDNA). Fragmented Ox-mtDNA enters the cytosol where it activates the NLRP3 inflammasome and generates IL-1β, IL-18, and cGAS-STING to induce type I interferons and interferon-stimulated genes. Inflammasome activation further enables the circulatory release of Ox-mtDNA by opening gasdermin D pores. We summarize new data showing that, in addition to being an autoimmune disease biomarker, Ox-mtDNA converts beneficial transient inflammation into long-lasting immunopathology. We discuss how Ox-mtDNA induces short- and long-term immune activation, and highlight its homeostatic and immunopathogenic functions.
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Affiliation(s)
- Hongxu Xian
- Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology, School of Medicine, University of California San Diego (UCSD), La Jolla, CA 92093, USA
| | - Michael Karin
- Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology, School of Medicine, University of California San Diego (UCSD), La Jolla, CA 92093, USA.
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4
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Mikhailov N, Hämäläinen RH. Modulating Mitochondrial DNA Heteroplasmy with Mitochondrially Targeted Endonucleases. Ann Biomed Eng 2022:10.1007/s10439-022-03051-7. [PMID: 36001180 DOI: 10.1007/s10439-022-03051-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 08/09/2022] [Indexed: 11/01/2022]
Abstract
Mitochondria, mainly known as energy factories of eukaryotic cells, also exert several additional signaling and metabolic functions and are today recognized as major cellular biosynthetic and signaling hubs. Mitochondria possess their own genome (mitochondrial DNA-mtDNA), that encodes proteins essential for oxidative phosphorylation, and mutations in it are an important contributor to human disease. The mtDNA mutations often exist in heteroplasmic conditions, with both healthy and mutant versions of the mtDNA residing in patients' cells and the level of mutant mtDNA may vary between different tissues and organs and affect the clinical outcome of the disease. Thus, shifting the ratio between healthy and mutant mtDNA in patients' cells provides an intriguing therapeutic option for mtDNA diseases. In this review we describe current strategies for modulating mitochondrial heteroplasmy levels with engineered endonucleases including mitochondrially targeted TALENs and Zinc finger nucleases (ZFNs) and discuss their therapeutic potential. These gene therapy tools could in the future provide therapeutic help both for patients with mitochondrial disease as well as in preventing the transfer of pathogenic mtDNA mutations from a mother to her offspring.
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Affiliation(s)
- Nikita Mikhailov
- A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Riikka H Hämäläinen
- A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland.
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5
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İbiş O, Yesari Selçuk A, Teber S, Baran M, Kaya A, Özcan S, Kefelioğlu H, Tez C. Complete mitogenomes of Turkish tree squirrels, Sciurus anomalus and S. vulgaris, (Sciuridae: Rodentia: Mammalia) and their phylogenetic status within the tribe Sciurini. Gene 2022; 841:146773. [PMID: 35905846 DOI: 10.1016/j.gene.2022.146773] [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: 03/09/2022] [Revised: 06/03/2022] [Accepted: 07/24/2022] [Indexed: 11/04/2022]
Abstract
The genus Sciurus, a member of the family Sciuridae, is widely distributed in the Holarctic region. To better understand mitogenomic characteristics and to reveal internal phylogenetic relationships of the genus, 20 complete mitogenomes of Turkish tree squirrels were successfully sequenced for the first time, including 19 for S. anomalus (from 16,505 bp to 16,510 bp) and one for S. vulgaris (16,511 bp). The mitogenomes of two species were AT-biased. All tRNAs for two species displayed a typical clover-leaf structure, except for tRNASer(AGY). The tRNA Serine1 (S1)-GCT structure lacked the dihydrouridine (DHU) loop and stem. Based on mitogenomic dataset for phylogeny of Sciurinae, phylogenetic analyses (Bayesian Inference and Maximum Likelihood) did not support monophyly of Sciurus and proposed that S. anomalus, the most basal taxa in the Sciurini tribe, had at least five mitogenome lineages, which were also supported by network analysis. The dissimilarities among the five linegaes of S. anomalus ranged from 0.0042 (0.42%) to 0.0062 (0.62%) using K2P sequence pairwise distances. In addition to this mitogenomic analysis result, phylogenetic analyses using the CYTB + D-loop dataset proposed the existence of at least nine lineages for S. anomalus, which was different than those of the previous studies. The current study proposed that the use of mitogenomic data for reconstructing the phylogeny of Turkey' Sciurus holds an important value for revealing evolutionary relationships.
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Affiliation(s)
- Osman İbiş
- Genome and Stem Cell Center, GENKOK, Erciyes University, Kayseri, Turkey; Vectors and Vector-Born Diseases Research and Implementation Center, Erciyes University, Kayseri, Turkey.
| | - Ahmet Yesari Selçuk
- Department of Agricultural Biotechnology, Faculty of Agriculture, Erciyes University, Kayseri, Turkey; Genome and Stem Cell Center, GENKOK, Erciyes University, Kayseri, Turkey.
| | - Saffet Teber
- Genome and Stem Cell Center, GENKOK, Erciyes University, Kayseri, Turkey.
| | - Mehmet Baran
- Genome and Stem Cell Center, GENKOK, Erciyes University, Kayseri, Turkey.
| | - Alaettin Kaya
- Department of Basic Sciences, Faculty of Veterinary Medicine, Dicle University, Diyarbakır, Turkey.
| | - Servet Özcan
- Genome and Stem Cell Center, GENKOK, Erciyes University, Kayseri, Turkey; Department of Biology, Faculty of Sciences, Erciyes University, Kayseri, Turkey.
| | - Haluk Kefelioğlu
- Department of Biology, Faculty of Science and Letters, Ondokuz Mayıs University, Samsun, Turkey.
| | - Coşkun Tez
- Genome and Stem Cell Center, GENKOK, Erciyes University, Kayseri, Turkey; Department of Biology, Faculty of Sciences, Erciyes University, Kayseri, Turkey.
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6
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Kosar M, Piccini D, Foiani M, Giannattasio M. A rapid method to visualize human mitochondrial DNA replication through rotary shadowing and transmission electron microscopy. Nucleic Acids Res 2021; 49:e121. [PMID: 34500456 PMCID: PMC8643652 DOI: 10.1093/nar/gkab770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 08/15/2021] [Accepted: 08/26/2021] [Indexed: 11/21/2022] Open
Abstract
We report a rapid experimental procedure based on high-density in vivo psoralen inter-strand DNA cross-linking coupled to spreading of naked purified DNA, positive staining, low-angle rotary shadowing, and transmission electron microscopy (TEM) that allows quick visualization of the dynamic of heavy strand (HS) and light strand (LS) human mitochondrial DNA replication. Replication maps built on linearized mitochondrial genomes and optimized rotary shadowing conditions enable clear visualization of the progression of the mitochondrial DNA synthesis and visualization of replication intermediates carrying long single-strand DNA stretches. One variant of this technique, called denaturing spreading, allowed the inspection of the fine chromatin structure of the mitochondrial genome and was applied to visualize the in vivo three-strand DNA structure of the human mitochondrial D-loop intermediate with unprecedented clarity.
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Affiliation(s)
- Martin Kosar
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milano, Italy
| | - Daniele Piccini
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milano, Italy
| | - Marco Foiani
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milano, Italy.,Dipartimento di Oncologia & Emato-Oncologia, Università degli Studi di Milano, Milano, Italy
| | - Michele Giannattasio
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milano, Italy.,Dipartimento di Oncologia & Emato-Oncologia, Università degli Studi di Milano, Milano, Italy
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7
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Inatomi T, Matsuda S, Ishiuchi T, Do Y, Nakayama M, Abe S, Kasho K, Wanrooij S, Nakada K, Ichiyanagi K, Sasaki H, Yasukawa T, Kang D. TFB2M and POLRMT are essential for mammalian mitochondrial DNA replication. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1869:119167. [PMID: 34744028 DOI: 10.1016/j.bbamcr.2021.119167] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 10/13/2021] [Accepted: 10/13/2021] [Indexed: 12/24/2022]
Abstract
Two classes of replication intermediates have been observed from mitochondrial DNA (mtDNA) in many mammalian tissue and cells with two-dimensional agarose gel electrophoresis. One is assigned to leading-strand synthesis in the absence of synchronous lagging-strand synthesis (strand-asynchronous replication), and the other has properties of coupled leading- and lagging-strand synthesis (strand-coupled replication). While strand-asynchronous replication is primed by long noncoding RNA synthesized from a defined transcription initiation site, little is known about the commencement of strand-coupled replication. To investigate it, we attempted to abolish strand-asynchronous replication in cultured human cybrid cells by knocking out the components of the transcription initiation complexes, mitochondrial transcription factor B2 (TFB2M/mtTFB2) and mitochondrial RNA polymerase (POLRMT/mtRNAP). Unexpectedly, removal of either protein resulted in complete mtDNA loss, demonstrating for the first time that TFB2M and POLRMT are indispensable for the maintenance of human mtDNA. Moreover, a lack of TFB2M could not be compensated for by mitochondrial transcription factor B1 (TFB1M/mtTFB1). These findings indicate that TFB2M and POLRMT are crucial for the priming of not only strand-asynchronous but also strand-coupled replication, providing deeper insights into the molecular basis of mtDNA replication initiation.
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Affiliation(s)
- Teppei Inatomi
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka-shi, Fukuoka 812-8582, Japan
| | - Shigeru Matsuda
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka-shi, Fukuoka 812-8582, Japan; Department of Modomics Biology and Medicine, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryocho, Aoba-ku, Sendai-shi, Miyagi 980-8575, Japan
| | - Takashi Ishiuchi
- Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka-shi, Fukuoka 812-8582, Japan
| | - Yura Do
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka-shi, Fukuoka 812-8582, Japan
| | - Masunari Nakayama
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka-shi, Fukuoka 812-8582, Japan
| | - Shusaku Abe
- Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka-shi, Fukuoka 812-8582, Japan
| | - Kazutoshi Kasho
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Sjoerd Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Kazuto Nakada
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba-shi, Ibaraki 305-8572, Japan
| | - Kenji Ichiyanagi
- Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya-shi, Aichi 464-8601, Japan
| | - Hiroyuki Sasaki
- Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka-shi, Fukuoka 812-8582, Japan
| | - Takehiro Yasukawa
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka-shi, Fukuoka 812-8582, Japan; Department of Pathology and Oncology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
| | - Dongchon Kang
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka-shi, Fukuoka 812-8582, Japan
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8
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Meunier I, Bocquet B, Defoort-Dhellemmes S, Smirnov V, Arndt C, Picot MC, Dollfus H, Charif M, Audo I, Huguet H, Zanlonghi X, Lenaers G. Characterization of SSBP1-related optic atrophy and foveopathy. Sci Rep 2021; 11:18703. [PMID: 34548540 PMCID: PMC8455542 DOI: 10.1038/s41598-021-98150-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 09/03/2021] [Indexed: 11/17/2022] Open
Abstract
Dominant optic atrophy (DOA) is genetically heterogeneous and most commonly caused by mutations in OPA1. To distinguish between the classical OPA1-related and the recently identified SSBP1-related DOAs, the retina and fovea of 27 patients carrying the SSBP1 p.Arg38Gln variant were scrutinized using 20° × 20° macular cube and 30° and 55° field fundus autofluorescence photographs. Age of onset, visual acuity, retinal nerve fiber layer and macular thicknesses were recorded. Three SSBP1-patients were asymptomatic, 10 had isolated DOA, and 12 had a combined DOA plus foveopathy. The foveopathy, with a tiny defect of the ellipsoid and interdigitation lines, was similar in all patients, independent of age. There were no significant statistical differences in terms of visual acuity and SD-OCT measurements between patients with isolated DOA (mean visual acuity in decimals: 0.54 ± 0.41) and those with combined foveopathy (0.50 ± 0.23). Two patients over 50 years of age developed a progressive rod-cone dystrophy, leading to severe visual impairment. SSBP1-related DOA shares similarities with OPA1-related DOA with an incomplete penetrance and an early childhood visual impairment. Nevertheless, the presence of a congenital foveopathy with no impact on visual acuity is a major criterion to distinguish SSBP1 cases and orient the appropriate genetic analysis.
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Affiliation(s)
- Isabelle Meunier
- National reference centre for inherited sensory diseases, University Hospital of Montpellier, University of Montpellier, Montpellier, France. .,Sensgene Care Network, Strasbourg, France. .,Institute for Neurosciences of Montpellier, Inserm, University of Montpellier, Montpellier, France.
| | - Béatrice Bocquet
- National reference centre for inherited sensory diseases, University Hospital of Montpellier, University of Montpellier, Montpellier, France.,Sensgene Care Network, Strasbourg, France.,Institute for Neurosciences of Montpellier, Inserm, University of Montpellier, Montpellier, France
| | - Sabine Defoort-Dhellemmes
- Sensgene Care Network, Strasbourg, France.,Department of Neuro-Ophthalmology and Electrophysiology, Robert Salengro Hospital, Lille, France
| | - Vasily Smirnov
- Sensgene Care Network, Strasbourg, France.,Department of Neuro-Ophthalmology and Electrophysiology, Robert Salengro Hospital, Lille, France
| | - Carl Arndt
- Department of Ophthalmology, University Hospital of Reims, Reims, France
| | - Marie Christine Picot
- Clinical Investigation Center (CIC) and Clinical Research and Epidemiology Unit (URCE), Montpellier, France
| | - Hélène Dollfus
- Sensgene Care Network, Strasbourg, France.,Department of Ophthalmology, National Center for Rare Disorders in Ophthalmic Genetics CARGO, Strasbourg Hospital, Strasbourg, France
| | - Majida Charif
- Genetics and Immuno-Cell Therapy Team, Mohammed First University, Oujda, Morocco
| | - Isabelle Audo
- Sensgene Care Network, Strasbourg, France.,CNRS, INSERM, Institut de la Vision, Sorbonne Université, Paris, France.,DHU Sight Restore, INSERM-DHOS CIC1423, CHNO des Quinze-Vingts, Paris, France
| | - Hélèna Huguet
- Clinical Investigation Center (CIC) and Clinical Research and Epidemiology Unit (URCE), Montpellier, France
| | - Xavier Zanlonghi
- Sensgene Care Network, Strasbourg, France.,Clinic Jules Verne, Nantes, France.,Department of Ophthalmology, University Hospital of Rennes, Rennes, France
| | - Guy Lenaers
- UMR CNRS 6015 - INSERM U1083, University of Angers MitoLab Team, University Hospital of Angers, Angers, France
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9
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Mitochondrial Dysfunction in Diseases, Longevity, and Treatment Resistance: Tuning Mitochondria Function as a Therapeutic Strategy. Genes (Basel) 2021; 12:genes12091348. [PMID: 34573330 PMCID: PMC8467098 DOI: 10.3390/genes12091348] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 01/31/2023] Open
Abstract
Mitochondria are very important intracellular organelles because they have various functions. They produce ATP, are involved in cell signaling and cell death, and are a major source of reactive oxygen species (ROS). Mitochondria have their own DNA (mtDNA) and mutation of mtDNA or change the mtDNA copy numbers leads to disease, cancer chemo/radioresistance and aging including longevity. In this review, we discuss the mtDNA mutation, mitochondrial disease, longevity, and importance of mitochondrial dysfunction in cancer first. In the later part, we particularly focus on the role in cancer resistance and the mitochondrial condition such as mtDNA copy number, mitochondrial membrane potential, ROS levels, and ATP production. We suggest a therapeutic strategy employing mitochondrial transplantation (mtTP) for treatment-resistant cancer.
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10
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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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11
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Dynamic proteomic profiling of human periodontal ligament stem cells during osteogenic differentiation. Stem Cell Res Ther 2021; 12:98. [PMID: 33536073 PMCID: PMC7860046 DOI: 10.1186/s13287-020-02123-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/25/2020] [Indexed: 01/07/2023] Open
Abstract
Background Human periodontal ligament stem cells (hPDLSCs) are ideal seed cells for periodontal regeneration. A greater understanding of the dynamic protein profiles during osteogenic differentiation contributed to the improvement of periodontal regeneration tissue engineering. Methods Tandem Mass Tag quantitative proteomics was utilized to reveal the temporal protein expression pattern during osteogenic differentiation of hPDLSCs on days 0, 3, 7 and 14. Differentially expressed proteins (DEPs) were clustered and functional annotated by Gene Ontology (GO) terms. Pathway enrichment analysis was performed based on the Kyoto Encyclopedia of Genes and Genomes database, followed by the predicted activation using Ingenuity Pathway Analysis software. Interaction networks of redox-sensitive signalling pathways and oxidative phosphorylation (OXPHOS) were conducted and the hub protein SOD2 was validated with western blotting. Results A total of 1024 DEPs were identified and clustered in 5 distinctive clusters representing dynamic tendencies. The GO enrichment results indicated that proteins with different tendencies show different functions. Pathway enrichment analysis found that OXPHOS was significantly involved, which further predicted continuous activation. Redox-sensitive signalling pathways with dynamic activation status showed associations with OXPHOS to various degrees, especially the sirtuin signalling pathway. SOD2, an important component of the sirtuin pathway, displays a persistent increase during osteogenesis. Data are available via ProteomeXchange with identifier PXD020908. Conclusion This is the first in-depth dynamic proteomic analysis of osteogenic differentiation of hPDLSCs. It demonstrated a dynamic regulatory mechanism of hPDLSC osteogenesis and might provide a new perspective for research on periodontal regeneration. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13287-020-02123-6.
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12
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Pabis K. Triplex and other DNA motifs show motif-specific associations with mitochondrial DNA deletions and species lifespan. Mech Ageing Dev 2021; 194:111429. [PMID: 33422563 DOI: 10.1016/j.mad.2021.111429] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 01/02/2021] [Accepted: 01/03/2021] [Indexed: 11/20/2022]
Abstract
The "theory of resistant biomolecules" posits that long-lived species show resistance to molecular damage at the level of their biomolecules. Here, we test this hypothesis in the context of mitochondrial DNA (mtDNA) as it implies that predicted mutagenic DNA motifs should be inversely correlated with species maximum lifespan (MLS). First, we confirmed that guanine-quadruplex and direct repeat (DR) motifs are mutagenic, as they associate with mtDNA deletions in the human major arc of mtDNA, while also adding mirror repeat (MR) and intramolecular triplex motifs to a growing list of potentially mutagenic features. What is more, triplex motifs showed disease-specific associations with deletions and an apparent interaction with guanine-quadruplex motifs. Surprisingly, even though DR, MR and guanine-quadruplex motifs were associated with mtDNA deletions, their correlation with MLS was explained by the biased base composition of mtDNA. Only triplex motifs negatively correlated with MLS even after adjusting for body mass, phylogeny, mtDNA base composition and effective number of codons. Taken together, our work highlights the importance of base composition for the comparative biogerontology of mtDNA and suggests that future research on mitochondrial triplex motifs is warranted.
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Affiliation(s)
- Kamil Pabis
- Georg August University of Göttingen, Göttingen, Germany.
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13
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Filograna R, Mennuni M, Alsina D, Larsson NG. Mitochondrial DNA copy number in human disease: the more the better? FEBS Lett 2020; 595:976-1002. [PMID: 33314045 PMCID: PMC8247411 DOI: 10.1002/1873-3468.14021] [Citation(s) in RCA: 202] [Impact Index Per Article: 50.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/02/2020] [Accepted: 11/26/2020] [Indexed: 12/19/2022]
Abstract
Most of the genetic information has been lost or transferred to the nucleus during the evolution of mitochondria. Nevertheless, mitochondria have retained their own genome that is essential for oxidative phosphorylation (OXPHOS). In mammals, a gene‐dense circular mitochondrial DNA (mtDNA) of about 16.5 kb encodes 13 proteins, which constitute only 1% of the mitochondrial proteome. Mammalian mtDNA is present in thousands of copies per cell and mutations often affect only a fraction of them. Most pathogenic human mtDNA mutations are recessive and only cause OXPHOS defects if present above a certain critical threshold. However, emerging evidence strongly suggests that the proportion of mutated mtDNA copies is not the only determinant of disease but that also the absolute copy number matters. In this review, we critically discuss current knowledge of the role of mtDNA copy number regulation in various types of human diseases, including mitochondrial disorders, neurodegenerative disorders and cancer, and during ageing. We also provide an overview of new exciting therapeutic strategies to directly manipulate mtDNA to restore OXPHOS in mitochondrial diseases.
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Affiliation(s)
- Roberta Filograna
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Mara Mennuni
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - David Alsina
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Nils-Göran Larsson
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
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14
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Freixer G, Zekri-Nechar K, Zamorano-León JJ, Hugo-Martínez C, Butta NV, Monzón E, Recio MJ, Giner M, López-Farré A. Pro-apoptotic properties and mitochondrial functionality in platelet-like-particles generated from low Aspirin-incubated Meg-01 cells. Platelets 2020; 32:1063-1072. [PMID: 33111589 DOI: 10.1080/09537104.2020.1839637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Long-term therapy with low Aspirin (ASA) dose is basis to prevent thrombotic acute events. However, the anti-platelet mechanisms of ASA remain not completely known. The aim was to analyze if in vitro exposure of human megakaryocytes to low ASA concentration may alter the apoptotic features of the newly formed platelets. Cultured Meg-01 cells, a human megakaryoblastic cell line, were stimulated to form platelets with 10 nmol/L phorbol 12-myristate-13-acetate (PMA) in the presence and absence of ASA (0.33 mmol/L). Results revealed that platelet-like particles (PLPs) derived from ASA-exposed Meg-01 cells, showed higher content of pro-apoptotic proteins Bax and Bak than PLPs from non-ASA incubated Meg-01 cells. It was accompanied of reduced cytochrome C oxidase activity and higher mitochondrial content of PTEN-induced putative kinase-1 in PLPs from ASA-incubated Meg-01 cells. However, only after calcium ionophore A23187 stimulation, caspase-3 activity, the cytosolic cytochrome C content, and reduction of mitochondrial membrane potential were higher in PLPs from ASA-incubated megakaryocytes than in those from Meg-01 without ASA. Nitric oxide synthase 3 content was higher in PLPs from ASA-exposed Meg-01 cells than in PLPs from non-ASA incubated Meg-01 cells. The L-arginine antagonist, NG-Nitro-L-arginine Methyl Ester, reduced caspase-3 activity in A23187-stimulated PLPs generated from ASA-incubated Meg-01 cells. As conclusions exposure of megakaryocyte to ASA promotes that the newly generated PLPs have, under stimulating condition, higher sensitivity to go into apoptosis than those PLPs generated from Meg-01 cells without ASA. It could be associated with differences in mitochondrial functionality and NO formation.
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Affiliation(s)
| | | | | | | | - Nora V Butta
- Haematology Department, Hospital Universitario La Paz, idiPaz, Madrid, Spain
| | - Elena Monzón
- Haematology Department, Hospital Universitario La Paz, idiPaz, Madrid, Spain
| | | | - Manel Giner
- Surgery Departments, School of Medicine, Universidad Complutense, Madrid, Spain
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15
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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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16
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Zhang H. Mechanisms of mutagenesis induced by DNA lesions: multiple factors affect mutations in translesion DNA synthesis. Crit Rev Biochem Mol Biol 2020; 55:219-251. [PMID: 32448001 DOI: 10.1080/10409238.2020.1768205] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Environmental mutagens lead to mutagenesis. However, the mechanisms are very complicated and not fully understood. Environmental mutagens produce various DNA lesions, including base-damaged or sugar-modified DNA lesions, as well as epigenetically modified DNA. DNA polymerases produce mutation spectra in translesion DNA synthesis (TLS) through misincorporation of incorrect nucleotides, frameshift deletions, blockage of DNA replication, imbalance of leading- and lagging-strand DNA synthesis, and genome instability. Motif or subunit in DNA polymerases further affects the mutations in TLS. Moreover, protein interactions and accessory proteins in DNA replisome also alter mutations in TLS, demonstrated by several representative DNA replisomes. Finally, in cells, multiple DNA polymerases or cellular proteins collaborate in TLS and reduce in vivo mutagenesis. Summaries and perspectives were listed. This review shows mechanisms of mutagenesis induced by DNA lesions and the effects of multiple factors on mutations in TLS in vitro and in vivo.
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Affiliation(s)
- Huidong Zhang
- Key Laboratory of Environment and Female Reproductive Health, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
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17
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Kaur P, Longley MJ, Pan H, Wang W, Countryman P, Wang H, Copeland WC. Single-molecule level structural dynamics of DNA unwinding by human mitochondrial Twinkle helicase. J Biol Chem 2020; 295:5564-5576. [PMID: 32213598 PMCID: PMC7186178 DOI: 10.1074/jbc.ra120.012795] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/24/2020] [Indexed: 11/06/2022] Open
Abstract
Knowledge of the molecular events in mitochondrial DNA (mtDNA) replication is crucial to understanding the origins of human disorders arising from mitochondrial dysfunction. Twinkle helicase is an essential component of mtDNA replication. Here, we employed atomic force microscopy imaging in air and liquids to visualize ring assembly, DNA binding, and unwinding activity of individual Twinkle hexamers at the single-molecule level. We observed that the Twinkle subunits self-assemble into hexamers and higher-order complexes that can switch between open and closed-ring configurations in the absence of DNA. Our analyses helped visualize Twinkle loading onto and unloading from DNA in an open-ringed configuration. They also revealed that closed-ring conformers bind and unwind several hundred base pairs of duplex DNA at an average rate of ∼240 bp/min. We found that the addition of mitochondrial single-stranded (ss) DNA-binding protein both influences the ways Twinkle loads onto defined DNA substrates and stabilizes the unwound ssDNA product, resulting in a ∼5-fold stimulation of the apparent DNA-unwinding rate. Mitochondrial ssDNA-binding protein also increased the estimated translocation processivity from 1750 to >9000 bp before helicase disassociation, suggesting that more than half of the mitochondrial genome could be unwound by Twinkle during a single DNA-binding event. The strategies used in this work provide a new platform to examine Twinkle disease variants and the core mtDNA replication machinery. They also offer an enhanced framework to investigate molecular mechanisms underlying deletion and depletion of the mitochondrial genome as observed in mitochondrial diseases.
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Affiliation(s)
- Parminder Kaur
- Physics Department, North Carolina State University, Raleigh, North Carolina 27695; Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina 27695.
| | - Matthew J Longley
- Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Hai Pan
- Physics Department, North Carolina State University, Raleigh, North Carolina 27695
| | - Wendy Wang
- Physics Department, North Carolina State University, Raleigh, North Carolina 27695
| | - Preston Countryman
- Physics Department, North Carolina State University, Raleigh, North Carolina 27695
| | - Hong Wang
- Physics Department, North Carolina State University, Raleigh, North Carolina 27695; Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina 27695; Toxicology Program, North Carolina State University, Raleigh, North Carolina 27695
| | - William C Copeland
- Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709.
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18
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Hoyos-Gonzalez N, Trasviña-Arenas CH, Degiorgi A, Castro-Lara AY, Peralta-Castro A, Jimenez-Sandoval P, Diaz-Quezada C, Lodi T, Baruffini E, Brieba LG. Modeling of pathogenic variants of mitochondrial DNA polymerase: insight into the replication defects and implication for human disease. Biochim Biophys Acta Gen Subj 2020; 1864:129608. [PMID: 32234506 DOI: 10.1016/j.bbagen.2020.129608] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 03/07/2020] [Accepted: 03/25/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND Mutations in human gene encoding the mitochondrial DNA polymerase γ (HsPolγ) are associated with a broad range of mitochondrial diseases. Here we studied the impact on DNA replication by disease variants clustered around residue HsPolγ-K1191, a residue that in several family-A DNA polymerases interacts with the 3' end of the primer. METHODS Specifically, we examined the effect of HsPolγ carrying pathogenic variants in residues D1184, I1185, C1188, K1191, D1196, and a stop codon at residue T1199, using as a model the yeast mitochondrial DNA polymerase protein, Mip1p. RESULTS The introduction of pathogenic variants C1188R (yV945R), and of a stop codon at residue T1199 (yT956X) abolished both polymerization and exonucleolysis in vitro. HsPolγ substitutions in residues D1184 (yD941), I1185 (yI942), K1191 (yK948) and D1196 (yD953) shifted the balance between polymerization and exonucleolysis in favor of exonucleolysis. HsPolγ pathogenic variants at residue K1191 (yK948) and D1184 (yD941) were capable of nucleotide incorporation albeit with reduced processivity. Structural analysis of mitochondrial DNAPs showed that residue HsPolγ-N864 is placed in an optimal distance to interact with the 3' end of the primer and the phosphate backbone previous to the 3' end. Amino acid changes in residue HsPolγ-N864 to Ala, Ser or Asp result in enzymes that did not decrease their polymerization activity on short templates but exhibited a substantial decrease for processive DNA synthesis. CONCLUSION Our data suggest that in mitochondrial DNA polymerases multiple amino acids are involved in the primer-stand stabilization.
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Affiliation(s)
- Nallely Hoyos-Gonzalez
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36821 Irapuato, Guanajuato, Mexico
| | - Carlos H Trasviña-Arenas
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36821 Irapuato, Guanajuato, Mexico
| | - Andrea Degiorgi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Atzimaba Y Castro-Lara
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36821 Irapuato, Guanajuato, Mexico
| | - Antolín Peralta-Castro
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36821 Irapuato, Guanajuato, Mexico
| | - Pedro Jimenez-Sandoval
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36821 Irapuato, Guanajuato, Mexico
| | - Corina Diaz-Quezada
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36821 Irapuato, Guanajuato, Mexico
| | - Tiziana Lodi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy
| | - Enrico Baruffini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy.
| | - Luis G Brieba
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36821 Irapuato, Guanajuato, Mexico.
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19
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Brosh RM, Matson SW. History of DNA Helicases. Genes (Basel) 2020; 11:genes11030255. [PMID: 32120966 PMCID: PMC7140857 DOI: 10.3390/genes11030255] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 12/13/2022] Open
Abstract
Since the discovery of the DNA double helix, there has been a fascination in understanding the molecular mechanisms and cellular processes that account for: (i) the transmission of genetic information from one generation to the next and (ii) the remarkable stability of the genome. Nucleic acid biologists have endeavored to unravel the mysteries of DNA not only to understand the processes of DNA replication, repair, recombination, and transcription but to also characterize the underlying basis of genetic diseases characterized by chromosomal instability. Perhaps unexpectedly at first, DNA helicases have arisen as a key class of enzymes to study in this latter capacity. From the first discovery of ATP-dependent DNA unwinding enzymes in the mid 1970's to the burgeoning of helicase-dependent pathways found to be prevalent in all kingdoms of life, the story of scientific discovery in helicase research is rich and informative. Over four decades after their discovery, we take this opportunity to provide a history of DNA helicases. No doubt, many chapters are left to be written. Nonetheless, at this juncture we are privileged to share our perspective on the DNA helicase field - where it has been, its current state, and where it is headed.
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Affiliation(s)
- Robert M. Brosh
- Section on DNA Helicases, Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
- Correspondence: (R.M.B.J.); (S.W.M.); Tel.: +1-410-558-8578 (R.M.B.J.); +1-919-962-0005 (S.W.M.)
| | - Steven W. Matson
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Correspondence: (R.M.B.J.); (S.W.M.); Tel.: +1-410-558-8578 (R.M.B.J.); +1-919-962-0005 (S.W.M.)
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20
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Melchinger H, Jain K, Tyagi T, Hwa J. Role of Platelet Mitochondria: Life in a Nucleus-Free Zone. Front Cardiovasc Med 2019; 6:153. [PMID: 31737646 PMCID: PMC6828734 DOI: 10.3389/fcvm.2019.00153] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 10/08/2019] [Indexed: 12/19/2022] Open
Abstract
Platelets are abundant, small, anucleate circulating cells, serving many emerging pathophysiological roles beyond hemostasis; including active critical roles in thrombosis, injury response, and immunoregulation. In the absence of genomic DNA transcriptional regulation (no nucleus), platelets require strategic prepackaging of all the needed RNA and organelles from megakaryocytes, to sense stress (e.g., hyperglycemia), to protect themselves from stress (e.g., mitophagy), and to communicate a stress response to other cells (e.g., granule and microparticle release). Distinct from avian thrombocytes that have a nucleus, the absence of a nucleus allows the mammalian platelet to maintain its small size, permits morphological flexibility, and may improve speed and efficiency of protein expression in response to stress. In the absence of a nucleus, platelet lifespan of 7–10 days, is largely determined by the mitochondria. The packaging of 5–8 mitochondria is critical in aerobic respiration and yielding metabolic substrates needed for function and survival. Mitochondria damage or dysfunction, as observed with several disease processes, results in greatly attenuated platelet survival and increased risk for thrombovascular events. Here we provide insights into the emerging roles of platelets despite the lack of a nucleus, and the key role played by mitochondria in platelet function and survival both in health and disease.
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Affiliation(s)
- Hannah Melchinger
- Department of Internal Medicine, Yale Cardiovascular Research Center, Yale School of Medicine, New Haven, CT, United States
| | - Kanika Jain
- Department of Internal Medicine, Yale Cardiovascular Research Center, Yale School of Medicine, New Haven, CT, United States
| | - Tarun Tyagi
- Department of Internal Medicine, Yale Cardiovascular Research Center, Yale School of Medicine, New Haven, CT, United States
| | - John Hwa
- Department of Internal Medicine, Yale Cardiovascular Research Center, Yale School of Medicine, New Haven, CT, United States
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21
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Abstract
Perturbed mitochondrial bioenergetics constitute a core pillar of cancer-associated metabolic dysfunction. While mitochondrial dysfunction in cancer may result from myriad biochemical causes, a historically neglected source is that of the mitochondrial genome. Recent large-scale sequencing efforts and clinical studies have highlighted the prevalence of mutations in mitochondrial DNA (mtDNA) in human tumours and their potential roles in cancer progression. In this review we discuss the biology of the mitochondrial genome, sources of mtDNA mutations, and experimental evidence of a role for mtDNA mutations in cancer. We also propose a ‘metabolic licensing’ model for mtDNA mutation-derived dysfunction in cancer initiation and progression.
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Affiliation(s)
- Payam A Gammage
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK. .,CRUK Beatson Institute for Cancer Research, Glasgow, UK.
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22
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Gu X, Kang X, Liu J. Mutation signatures in germline mitochondrial genome provide insights into human mitochondrial evolution and disease. Hum Genet 2019; 138:613-624. [PMID: 30968252 DOI: 10.1007/s00439-019-02009-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 04/02/2019] [Indexed: 01/06/2023]
Abstract
Variations in mitochondrial DNA (mtDNA) have been fundamental for understanding human evolution and are causative for a plethora of inherited mitochondrial diseases, but the mutation signatures of germline mtDNA and their value in understanding mitochondrial pathogenicity remain unknown. Here, we carried out a systematic analysis of mutation patterns in germline mtDNA based on 97,566 mtDNA variants from 45,494 full-length sequences and revealed a highly non-stochastic and replication-coupled mutation signature characterized by nucleotide-specific mutation pressure (G > T>A > C) and position-specific selection pressure, suggesting the existence of an intensive mutation-selection interplay in germline mtDNA. We provide evidence that this mutation-selection interplay has strongly shaped the mtDNA sequence during evolution, which not only manifests as an oriented alteration of amino acid compositions of mitochondrial encoded proteins, but also explains the long-lasting mystery of CpG depletion in mitochondrial genome. Finally, we demonstrated that these insights may be integrated to better understand the pathogenicity of disease-implicated mitochondrial variants.
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Affiliation(s)
- Xiwen Gu
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, Xi'an, 710004, China.
| | - Xinyun Kang
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, Xi'an, 710004, China
| | - Jiankang Liu
- Center for Mitochondrial Biology and Medicine & Douglas C. Wallace Institute for Mitochondrial and Epigenetic Information Sciences, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, China.
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23
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Persson Ö, Muthukumar Y, Basu S, Jenninger L, Uhler JP, Berglund AK, McFarland R, Taylor RW, Gustafsson CM, Larsson E, Falkenberg M. Copy-choice recombination during mitochondrial L-strand synthesis causes DNA deletions. Nat Commun 2019; 10:759. [PMID: 30770810 PMCID: PMC6377680 DOI: 10.1038/s41467-019-08673-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/21/2019] [Indexed: 11/08/2022] Open
Abstract
Mitochondrial DNA (mtDNA) deletions are associated with mitochondrial disease, and also accumulate during normal human ageing. The mechanisms underlying mtDNA deletions remain unknown although several models have been proposed. Here we use deep sequencing to characterize abundant mtDNA deletions in patients with mutations in mitochondrial DNA replication factors, and show that these have distinct directionality and repeat characteristics. Furthermore, we recreate the deletion formation process in vitro using only purified mitochondrial proteins and defined DNA templates. Based on our in vivo and in vitro findings, we conclude that mtDNA deletion formation involves copy-choice recombination during replication of the mtDNA light strand.
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Affiliation(s)
- Örjan Persson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, Gothenburg, SE-405 30, Sweden
| | - Yazh Muthukumar
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, Gothenburg, SE-405 30, Sweden
| | - Swaraj Basu
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, Gothenburg, SE-405 30, Sweden
| | - Louise Jenninger
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, Gothenburg, SE-405 30, Sweden
| | - Jay P Uhler
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, Gothenburg, SE-405 30, Sweden
| | - Anna-Karin Berglund
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, Gothenburg, SE-405 30, Sweden
| | - Robert McFarland
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Claes M Gustafsson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, Gothenburg, SE-405 30, Sweden
| | - Erik Larsson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, Gothenburg, SE-405 30, Sweden.
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, Gothenburg, SE-405 30, Sweden.
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Abstract
The maternally inherited mitochondrial DNA (mtDNA) is located inside every mitochondrion, in variable number of copies, and it contains 37 crucial genes for cellular bioenergetics. This chapter will discuss the unique features of this circular genome including heteroplasmy, haplogroups, among others, along with the corresponding clinical relevance for each. The discussion also covers the nuclear-encoded mitochondrial genes (N > 1000) and the epistatic interactions between mtDNA and the nuclear genome. Examples of mitochondrial diseases related to specific mtDNA mutation sites of relevance for humans are provided. This chapter aims to provide an overview of mitochondrial genetics as an emerging hot topic for the future of medicine.
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Affiliation(s)
- Vanessa F Gonçalves
- Molecular Brain Sciences Department, Centre for Addiction and Mental Health, Toronto, Canada.
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25
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Yasukawa T, Kang D. An overview of mammalian mitochondrial DNA replication mechanisms. J Biochem 2018; 164:183-193. [PMID: 29931097 PMCID: PMC6094444 DOI: 10.1093/jb/mvy058] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/15/2018] [Indexed: 11/14/2022] Open
Abstract
While the majority of DNA is enclosed within the nucleus, the mitochondria also contain their own, separate DNA, the mitochondrial DNA (mtDNA). Mutations in mtDNA are associated with various human diseases, demonstrating the importance of mtDNA. Intensive studies over the last 18 years have demonstrated the presence of two distinct classes of mtDNA replication intermediates in mammals. One involves leading-strand DNA synthesis in the absence of synchronous lagging-strand DNA synthesis. Currently there are competing models in which the lagging-strand template is either systematically hybridized to processed mitochondrial transcripts, or coated with protein, until the lagging-strand DNA synthesis takes place. The other class of mtDNA replication intermediates has many properties of conventional, coupled leading- and lagging-strand DNA synthesis. Additionally, the highly unusual arrangement of DNA in human heart mitochondria suggests a third mechanism of replication. These findings indicate that the mtDNA replication systems of humans and other mammals are far more complex than previously thought, and thereby will require further research to understand the full picture of mtDNA replication.
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Affiliation(s)
- Takehiro Yasukawa
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Japan
| | - Dongchon Kang
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Japan
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26
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The presence of rNTPs decreases the speed of mitochondrial DNA replication. PLoS Genet 2018; 14:e1007315. [PMID: 29601571 PMCID: PMC5895052 DOI: 10.1371/journal.pgen.1007315] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 04/11/2018] [Accepted: 03/19/2018] [Indexed: 11/19/2022] Open
Abstract
Ribonucleotides (rNMPs) are frequently incorporated during replication or repair by DNA polymerases and failure to remove them leads to instability of nuclear DNA (nDNA). Conversely, rNMPs appear to be relatively well-tolerated in mitochondrial DNA (mtDNA), although the mechanisms behind the tolerance remain unclear. We here show that the human mitochondrial DNA polymerase gamma (Pol γ) bypasses single rNMPs with an unprecedentedly high fidelity and efficiency. In addition, Pol γ exhibits a strikingly low frequency of rNMP incorporation, a property, which we find is independent of its exonuclease activity. However, the physiological levels of free rNTPs partially inhibit DNA synthesis by Pol γ and render the polymerase more sensitive to imbalanced dNTP pools. The characteristics of Pol γ reported here could have implications for forms of mtDNA depletion syndrome (MDS) that are associated with imbalanced cellular dNTP pools. Our results show that at the rNTP/dNTP ratios that are expected to prevail in such disease states, Pol γ enters a polymerase/exonuclease idling mode that leads to mtDNA replication stalling. This could ultimately lead to mtDNA depletion and, consequently, to mitochondrial disease phenotypes such as those observed in MDS.
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27
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Abstract
Mitochondria play a crucial role in a variety of cellular processes ranging from energy metabolism, generation of reactive oxygen species (ROS) and Ca(2+) handling to stress responses, cell survival and death. Malfunction of the organelle may contribute to the pathogenesis of neuromuscular, cancer, premature aging and cardiovascular diseases (CVD), including myocardial ischemia, cardiomyopathy and heart failure (HF). Mitochondria contain their own genome organized into DNA-protein complexes, called "mitochondrial nucleoids," along with multiprotein machineries, which promote mitochondrial DNA (mtDNA) replication, transcription and repair. Although the mammalian organelle possesses almost all known nuclear DNA repair pathways, including base excision repair, mismatch repair and recombinational repair, the proximity of mtDNA to the main sites of ROS production and the lack of protective histones may result in increased susceptibility to various types of mtDNA damage. These include accumulation of mtDNA point mutations and/or deletions and decreased mtDNA copy number, which will impair mitochondrial function and finally, may lead to CVD including HF.
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Affiliation(s)
- José Marín-García
- The Molecular Cardiology and Neuromuscular Institute, 75 Raritan Avenue, Highland Park, NJ, 08904, USA.
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28
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Jia PP, Junaid M, Ma YB, Ahmad F, Jia YF, Li WG, Pei DS. Role of human DNA2 (hDNA2) as a potential target for cancer and other diseases: A systematic review. DNA Repair (Amst) 2017; 59:9-19. [PMID: 28903076 DOI: 10.1016/j.dnarep.2017.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/29/2017] [Accepted: 09/01/2017] [Indexed: 11/28/2022]
Abstract
DNA nuclease/helicase 2 (DNA2), a multi-functional protein protecting the high fidelity of genomic transmission, plays critical roles in DNA replication and repair processes. In the maturation of Okazaki fragments, DNA2 acts synergistically with other enzymes to cleave the DNA-RNA primer flaps via different pathways. DNA2 is also involved in the stability of mitochondrial DNA and the maintenance of telomeres. Moreover, DNA2 potentially participates in controlling the cell cycle by repairing the DNA replication faults at main checkpoints. In addition, previous evidences demonstrated that DNA2 also functions in the repair process of DNA damages, such as base excision repair (BER). Currently, large studies revealed the structures and functions of DNA2 in prokaryotes and unicellular eukaryotes, such as bacteria and yeast. However, the studies that highlighted the functions of human DNA2 (hDNA2) and the relationships with other multifunctional proteins are still elusive, and more precise investigations are immensely needed. Therefore, this review mainly encompasses the key functions of DNA2 in human cells with various aspects, especially focusing on the genome integrity, and also generalizes the recent insights to the mechanisms related to the occurrence of cancer and other diseases potentially linked to the mutations in DNA2.
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Affiliation(s)
- Pan-Pan Jia
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122, China; College of Life Science, Henan Normal University, Xinxiang 453007, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Muhammad Junaid
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan-Bo Ma
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122, China
| | - Farooq Ahmad
- Sustainable Development Study Centre, GC University Lahore, Pakistan
| | - Yong-Fang Jia
- College of Life Science, Henan Normal University, Xinxiang 453007, China
| | - Wei-Guo Li
- College of Life Science, Henan Normal University, Xinxiang 453007, China.
| | - De-Sheng Pei
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122, China.
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29
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Boldinova EO, Wanrooij PH, Shilkin ES, Wanrooij S, Makarova AV. DNA Damage Tolerance by Eukaryotic DNA Polymerase and Primase PrimPol. Int J Mol Sci 2017; 18:E1584. [PMID: 28754021 PMCID: PMC5536071 DOI: 10.3390/ijms18071584] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 07/14/2017] [Accepted: 07/16/2017] [Indexed: 12/31/2022] Open
Abstract
PrimPol is a human deoxyribonucleic acid (DNA) polymerase that also possesses primase activity and is involved in DNA damage tolerance, the prevention of genome instability and mitochondrial DNA maintenance. In this review, we focus on recent advances in biochemical and crystallographic studies of PrimPol, as well as in identification of new protein-protein interaction partners. Furthermore, we discuss the possible functions of PrimPol in both the nucleus and the mitochondria.
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Affiliation(s)
- Elizaveta O Boldinova
- Institute of Molecular Genetics of Russian Academy of Sciences, Kurchatov sq. 2, 123182 Moscow, Russia.
| | - Paulina H Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87 Umeå, Sweden.
| | - Evgeniy S Shilkin
- Institute of Molecular Genetics of Russian Academy of Sciences, Kurchatov sq. 2, 123182 Moscow, Russia.
| | - Sjoerd Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87 Umeå, Sweden.
| | - Alena V Makarova
- Institute of Molecular Genetics of Russian Academy of Sciences, Kurchatov sq. 2, 123182 Moscow, Russia.
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30
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Pokrzywinski KL, Biel TG, Kryndushkin D, Rao VA. Therapeutic Targeting of the Mitochondria Initiates Excessive Superoxide Production and Mitochondrial Depolarization Causing Decreased mtDNA Integrity. PLoS One 2016; 11:e0168283. [PMID: 28030582 PMCID: PMC5193408 DOI: 10.1371/journal.pone.0168283] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/29/2016] [Indexed: 01/01/2023] Open
Abstract
Mitochondrial dysregulation is closely associated with excessive reactive oxygen species (ROS) production. Altered redox homeostasis has been implicated in the onset of several diseases including cancer. Mitochondrial DNA (mtDNA) and proteins are particularly sensitive to ROS as they are in close proximity to the respiratory chain (RC). Mitoquinone (MitoQ), a mitochondria-targeted redox agent, selectively damages breast cancer cells possibly through damage induced via enhanced ROS production. However, the effects of MitoQ and other triphenylphosphonium (TPP+) conjugated agents on cancer mitochondrial homeostasis remain unknown. The primary objective of this study was to determine the impact of mitochondria-targeted agent [(MTAs) conjugated to TPP+: mitoTEMPOL, mitoquinone and mitochromanol-acetate] on mitochondrial physiology and mtDNA integrity in breast (MDA-MB-231) and lung (H23) cancer cells. The integrity of the mtDNA was assessed by quantifying the degree of mtDNA fragmentation and copy number, as well as by measuring mitochondrial proteins essential to mtDNA stability and maintenance (TFAM, SSBP1, TWINKLE, POLG and POLRMT). Mitochondrial status was evaluated by measuring superoxide production, mitochondrial membrane depolarization, oxygen consumption, extracellular acidification and mRNA or protein levels of the RC complexes along with TCA cycle activity. In this study, we demonstrated that all investigated MTAs impair mitochondrial health and decrease mtDNA integrity in MDA-MB-231 and H23 cells. However, differences in the degree of mitochondrial damage and mtDNA degradation suggest unique properties among each MTA that may be cell line, dose and time dependent. Collectively, our study indicates the potential for TPP+ conjugated molecules to impair breast and lung cancer cells by targeting mitochondrial homeostasis.
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Affiliation(s)
- Kaytee L. Pokrzywinski
- Laboratory of Applied Biochemistry, Division of Biotechnology Research and Review III, Office of Biotechnology Products, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Thomas G. Biel
- Laboratory of Applied Biochemistry, Division of Biotechnology Research and Review III, Office of Biotechnology Products, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Dmitry Kryndushkin
- Laboratory of Applied Biochemistry, Division of Biotechnology Research and Review III, Office of Biotechnology Products, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - V. Ashutosh Rao
- Laboratory of Applied Biochemistry, Division of Biotechnology Research and Review III, Office of Biotechnology Products, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, United States of America
- * E-mail:
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31
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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: 411] [Impact Index Per Article: 51.4] [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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32
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Unbiased Mitoproteome Analyses Confirm Non-canonical RNA, Expanded Codon Translations. Comput Struct Biotechnol J 2016; 14:391-403. [PMID: 27830053 PMCID: PMC5094600 DOI: 10.1016/j.csbj.2016.09.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/28/2016] [Accepted: 09/29/2016] [Indexed: 01/14/2023] Open
Abstract
Proteomic MS/MS mass spectrometry detections are usually biased towards peptides cleaved by experimentally added digestion enzyme(s). Hence peptides resulting from spontaneous degradation and natural proteolysis usually remain undetected. Previous analyses of tryptic human proteome data (cleavage after K, R) detected non-canonical tryptic peptides translated according to tetra- and pentacodons (codons expanded by silent mono- and dinucleotides), and from transcripts systematically (a) deleting mono-, dinucleotides after trinucleotides (delRNAs), (b) exchanging nucleotides according to 23 bijective transformations. Nine symmetric and fourteen asymmetric nucleotide exchanges (X ↔ Y, e.g. A ↔ C; and X → Y → Z → X, e.g. A → C → G → A) produce swinger RNAs. Here unbiased reanalyses of these proteomic data detect preferentially non-canonical tryptic peptides despite assuming random cleavage. Unbiased analyses couldn't reconstruct experimental tryptic digestion if most detected non-canonical peptides were false positives. Detected non-tryptic non-canonical peptides map preferentially on corresponding, previously described non-canonical transcripts, as for tryptic non-canonical peptides. Hence unbiased analyses independently confirm previous trypsin-biased analyses that showed translations of del- and swinger RNA and expanded codons. Accounting for natural proteolysis completes trypsin-biased mitopeptidome analyses, independently confirms non-canonical transcriptions and translations.
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33
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Uhler JP, Thörn C, Nicholls TJ, Matic S, Milenkovic D, Gustafsson CM, Falkenberg M. MGME1 processes flaps into ligatable nicks in concert with DNA polymerase γ during mtDNA replication. Nucleic Acids Res 2016; 44:5861-71. [PMID: 27220468 PMCID: PMC4937333 DOI: 10.1093/nar/gkw468] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 05/11/2016] [Accepted: 05/13/2016] [Indexed: 12/17/2022] Open
Abstract
Recently, MGME1 was identified as a mitochondrial DNA nuclease with preference for single-stranded DNA (ssDNA) substrates. Loss-of-function mutations in patients lead to mitochondrial disease with DNA depletion, deletions, duplications and rearrangements. Here, we assess the biochemical role of MGME1 in the processing of flap intermediates during mitochondrial DNA replication using reconstituted systems. We show that MGME1 can cleave flaps to enable efficient ligation of newly replicated DNA strands in combination with POLγ. MGME1 generates a pool of imprecisely cut products (short flaps, nicks and gaps) that are converted to ligatable nicks by POLγ through extension or excision of the 3'-end strand. This is dependent on the 3'-5' exonuclease activity of POLγ which limits strand displacement activity and enables POLγ to back up to the nick by 3'-5' degradation. We also demonstrate that POLγ-driven strand displacement is sufficient to generate DNA- but not RNA-flap substrates suitable for MGME1 cleavage and ligation during replication. Our findings have implications for RNA primer removal models, the 5'-end processing of nascent DNA at OriH, and DNA repair.
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Affiliation(s)
- Jay P Uhler
- Institute of Biomedicine, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Christian Thörn
- Institute of Biomedicine, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Thomas J Nicholls
- Institute of Biomedicine, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Stanka Matic
- Max Planck Institute for Biology of Ageing, 50391 Cologne, Germany
| | | | - Claes M Gustafsson
- Institute of Biomedicine, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Maria Falkenberg
- Institute of Biomedicine, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
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34
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Oxidative DNA damage stalls the human mitochondrial replisome. Sci Rep 2016; 6:28942. [PMID: 27364318 PMCID: PMC4929447 DOI: 10.1038/srep28942] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 05/31/2016] [Indexed: 12/27/2022] Open
Abstract
Oxidative stress is capable of causing damage to various cellular constituents, including DNA. There is however limited knowledge on how oxidative stress influences mitochondrial DNA and its replication. Here, we have used purified mtDNA replication proteins, i.e. DNA polymerase γ holoenzyme, the mitochondrial single-stranded DNA binding protein mtSSB, the replicative helicase Twinkle and the proposed mitochondrial translesion synthesis polymerase PrimPol to study lesion bypass synthesis on oxidative damage-containing DNA templates. Our studies were carried out at dNTP levels representative of those prevailing either in cycling or in non-dividing cells. At dNTP concentrations that mimic those in cycling cells, the replication machinery showed substantial stalling at sites of damage, and these problems were further exacerbated at the lower dNTP concentrations present in resting cells. PrimPol, the translesion synthesis polymerase identified inside mammalian mitochondria, did not promote mtDNA replication fork bypass of the damage. This argues against a conventional role for PrimPol as a mitochondrial translesion synthesis DNA polymerase for oxidative DNA damage; however, we show that Twinkle, the mtDNA replicative helicase, is able to stimulate PrimPol DNA synthesis in vitro, suggestive of an as yet unidentified role of PrimPol in mtDNA metabolism.
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35
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Khan I, Crouch JD, Bharti SK, Sommers JA, Carney SM, Yakubovskaya E, Garcia-Diaz M, Trakselis MA, Brosh RM. Biochemical Characterization of the Human Mitochondrial Replicative Twinkle Helicase: SUBSTRATE SPECIFICITY, DNA BRANCH MIGRATION, AND ABILITY TO OVERCOME BLOCKADES TO DNA UNWINDING. J Biol Chem 2016; 291:14324-14339. [PMID: 27226550 DOI: 10.1074/jbc.m115.712026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Indexed: 01/08/2023] Open
Abstract
Mutations in the c10orf2 gene encoding the human mitochondrial DNA replicative helicase Twinkle are linked to several rare genetic diseases characterized by mitochondrial defects. In this study, we have examined the catalytic activity of Twinkle helicase on model replication fork and DNA repair structures. Although Twinkle behaves as a traditional 5' to 3' helicase on conventional forked duplex substrates, the enzyme efficiently dissociates D-loop DNA substrates irrespective of whether it possesses a 5' or 3' single-stranded tailed invading strand. In contrast, we report for the first time that Twinkle branch-migrates an open-ended mobile three-stranded DNA structure with a strong 5' to 3' directionality preference. To determine how well Twinkle handles potential roadblocks to mtDNA replication, we tested the ability of the helicase to unwind substrates with site-specific oxidative DNA lesions or bound by the mitochondrial transcription factor A. Twinkle helicase is inhibited by DNA damage in a unique manner that is dependent on the type of oxidative lesion and the strand in which it resides. Novel single molecule FRET binding and unwinding assays show an interaction of the excluded strand with Twinkle as well as events corresponding to stepwise unwinding and annealing. TFAM inhibits Twinkle unwinding, suggesting other replisome proteins may be required for efficient removal. These studies shed new insight on the catalytic functions of Twinkle on the key DNA structures it would encounter during replication or possibly repair of the mitochondrial genome and how well it tolerates potential roadblocks to DNA unwinding.
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Affiliation(s)
- Irfan Khan
- Laboratory of Molecular Gerontology, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Jack D Crouch
- Laboratory of Molecular Gerontology, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Sanjay Kumar Bharti
- Laboratory of Molecular Gerontology, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Joshua A Sommers
- Laboratory of Molecular Gerontology, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Sean M Carney
- Molecular Biophysics and Structural Biology Program, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Elena Yakubovskaya
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York 11794-8651
| | - Miguel Garcia-Diaz
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York 11794-8651
| | - Michael A Trakselis
- Molecular Biophysics and Structural Biology Program, University of Pittsburgh, Pittsburgh, Pennsylvania 15260,; Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798
| | - Robert M Brosh
- Laboratory of Molecular Gerontology, NIA, National Institutes of Health, Baltimore, Maryland 21224,.
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36
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Janssen W, Quaegebeur A, Van Goethem G, Ann L, Smets K, Vandenberghe R, Van Paesschen W. The spectrum of epilepsy caused by POLG mutations. Acta Neurol Belg 2016; 116:17-25. [PMID: 26104464 DOI: 10.1007/s13760-015-0499-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 06/08/2015] [Indexed: 12/21/2022]
Abstract
Mutations in POLG are increasingly recognized as a cause of refractory occipital lobe epilepsy (OLE) and status epilepticus (SE). Our aim was to describe the epilepsy syndrome in seven patients with POLG mutations. We retrospectively reviewed the medical records of seven patients with POLG mutations and epilepsy. Mutation analysis was performed by direct sequencing of the coding exons of the POLG gene. Disease onset was at a median age of 18 years (range 12-26). Epilepsy was the presenting problem in six patients. All had focal seizures, with motor (n = 6) and visual (n = 6) phenomena. Six patients had secondarily generalized seizures and two patients had myoclonic seizures. Six patients had one or more episodes of refractory SE, including focal (n = 5), subtle (n = 4), myoclonic (n = 2) and convulsive (n = 3) SE. During or after SE, brain MRI showed lesions affecting the occipital lobe in all patients, probably due to continuous epileptic activity. Five of the six patients with SE died during treatment of SE, one due to valproate-induced hepatotoxicity. Associated clinical symptoms were ataxia (n = 6), polyneuropathy (n = 6), progressive external ophthalmoplegia (PEO) (n = 3) and migraine (n = 3). Epilepsy may be the first and dominant neurological problem caused by POLG mutations. The epilepsy may be severe and the condition of the patient may end in fatal SE. Refractory OLE and SE in a patient with polyneuropathy, ataxia, PEO or migraine warrant screening for POLG mutations. In this clinical setting, valproate should not be given in view of the risk of fatal hepatotoxicity.
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Affiliation(s)
- Wouter Janssen
- Department of Neurology, University Hospitals Leuven, Herestraat 49, 3000, Louvain, Belgium.
| | - Annelies Quaegebeur
- Department of Neurology, University Hospitals Leuven, Herestraat 49, 3000, Louvain, Belgium
| | - Gert Van Goethem
- Neurogenetics Group, Department of Molecular Genetics, VIB, Antwerp, Belgium
- Laboratory of Neurogenetics, Institute Born-Bunge, Antwerp, Belgium
- University of Antwerpen, Antwerp, Belgium
- Department of Neurology, University Hospital Antwerpen, Antwerp, Belgium
| | - Löfgren Ann
- Laboratory of Neurogenetics, Institute Born-Bunge, Antwerp, Belgium
- University of Antwerpen, Antwerp, Belgium
| | - Katrien Smets
- Neurogenetics Group, Department of Molecular Genetics, VIB, Antwerp, Belgium
- Laboratory of Neurogenetics, Institute Born-Bunge, Antwerp, Belgium
- University of Antwerpen, Antwerp, Belgium
- Department of Neurology, University Hospital Antwerpen, Antwerp, Belgium
| | - Rik Vandenberghe
- Department of Neurology, University Hospitals Leuven, Herestraat 49, 3000, Louvain, Belgium
| | - Wim Van Paesschen
- Department of Neurology, University Hospitals Leuven, Herestraat 49, 3000, Louvain, Belgium.
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Bianchessi V, Vinci MC, Nigro P, Rizzi V, Farina F, Capogrossi MC, Pompilio G, Gualdi V, Lauri A. Methylation profiling by bisulfite sequencing analysis of the mtDNA Non-Coding Region in replicative and senescent Endothelial Cells. Mitochondrion 2016; 27:40-7. [PMID: 26910457 DOI: 10.1016/j.mito.2016.02.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 02/19/2016] [Accepted: 02/19/2016] [Indexed: 12/21/2022]
Abstract
The regulation and function of Mitochondrial DNA (mtDNA) cytosine methylation (5 mC) are largely unexplored. Mitochondria, Endothelial Cell (EC) senescence, and cardiovascular dysfunction are closely related. We extensively investigated the mtDNA Non-Coding Region (NCR) methylation pattern and its variations in EC replicative senescence. We observed previously undescribed 5 mC clusters and a biased distribution of 5 mC among DNA sites and throughout the NCR. The methylation pattern in senescent EC showed non-random variations, including the hypo-methylation of mtDNA replication regulatory sites. Additional experiments opened to a possible role for 5 mC in D-loop formation, rather than in mitochondrial gene expression.
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Affiliation(s)
- Valentina Bianchessi
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino (CCM), IRCCS, Milano, Italy
| | | | - Patrizia Nigro
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino (CCM), IRCCS, Milano, Italy
| | - Valeria Rizzi
- Genomics Core, Parco Tecnologico Padano, Lodi, Italy
| | - Floriana Farina
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino (CCM), IRCCS, Milano, Italy
| | - Maurizio C Capogrossi
- Laboratory of Vascular Pathology, Istituto Dermopatico dell'Immacolata (IDI), IRCCS, Roma, Italy
| | - Giulio Pompilio
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino (CCM), IRCCS, Milano, Italy
| | | | - Andrea Lauri
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino (CCM), IRCCS, Milano, Italy.
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38
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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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39
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Uittenbogaard M, Chiaramello A. Novel subcellular localization of the DNA helicase Twinkle at the kinetochore complex during mitosis in neuronal-like progenitor cells. Histochem Cell Biol 2015; 145:275-86. [PMID: 26678504 DOI: 10.1007/s00418-015-1388-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2015] [Indexed: 11/28/2022]
Abstract
During mitosis, the kinetochore, a multi-protein structure located on the centromeric DNA, is responsible for proper segregation of the replicated genome. More specifically, the outer kinetochore complex component Ndc80/Hec1 plays a critical role in regulating microtubule attachment to the spindle for accurate sister chromatid segregation. In addition, DNA helicases play a key contribution for precise and complete disjunction of sister chromatids held together through double-stranded DNA catenations until anaphase. In this study, we focused our attention on the nuclear-encoded DNA helicase Twinkle, which functions as an essential helicase for replication of mitochondrial DNA. It regulates the copy number of the mitochondrial genome, while maintaining its integrity, two processes essential for mitochondrial biogenesis and bioenergetic functions. Although the majority of the Twinkle protein is imported into mitochondria, a small fraction remains cytosolic with an unknown function. In this study, we report a novel expression pattern of Twinkle during chromosomal segregation at distinct mitotic phases. By immunofluorescence microscopy, we found that Twinkle protein colocalizes with the outer kinetochore protein HEC1 as early as prophase until late anaphase in neuronal-like progenitor cells. Thus, our collective results have revealed an unexpected cell cycle-regulated expression pattern of the DNA helicase Twinkle, known for its role in mtDNA replication. Therefore, its recruitment to the kinetochore suggests an evolutionary conserved function for both mitochondrial and nuclear genomic inheritance.
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Affiliation(s)
- Martine Uittenbogaard
- Department of Anatomy and Regenerative Biology, George Washington University Medical Center, 2300 I Street N.W., Washington, DC, 20037, USA
| | - Anne Chiaramello
- Department of Anatomy and Regenerative Biology, George Washington University Medical Center, 2300 I Street N.W., Washington, DC, 20037, USA.
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40
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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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41
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Primer removal during mammalian mitochondrial DNA replication. DNA Repair (Amst) 2015; 34:28-38. [PMID: 26303841 DOI: 10.1016/j.dnarep.2015.07.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 07/02/2015] [Indexed: 12/17/2022]
Abstract
The small circular mitochondrial genome in mammalian cells is replicated by a dedicated replisome, defects in which can cause mitochondrial disease in humans. A fundamental step in mitochondrial DNA (mtDNA) replication and maintenance is the removal of the RNA primers needed for replication initiation. The nucleases RNase H1, FEN1, DNA2, and MGME1 have been implicated in this process. Here we review the role of these nucleases in the light of primer removal pathways in mitochondria, highlight associations with disease, as well as consider the implications for mtDNA replication initiation.
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42
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Jemt E, Persson Ö, Shi Y, Mehmedovic M, Uhler JP, Dávila López M, Freyer C, Gustafsson CM, Samuelsson T, Falkenberg M. Regulation of DNA replication at the end of the mitochondrial D-loop involves the helicase TWINKLE and a conserved sequence element. Nucleic Acids Res 2015; 43:9262-75. [PMID: 26253742 PMCID: PMC4627069 DOI: 10.1093/nar/gkv804] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 07/28/2015] [Indexed: 11/12/2022] Open
Abstract
The majority of mitochondrial DNA replication events are terminated prematurely. The nascent DNA remains stably associated with the template, forming a triple-stranded displacement loop (D-loop) structure. However, the function of the D-loop region of the mitochondrial genome remains poorly understood. Using a comparative genomics approach we here identify two closely related 15 nt sequence motifs of the D-loop, strongly conserved among vertebrates. One motif is at the D-loop 5'-end and is part of the conserved sequence block 1 (CSB1). The other motif, here denoted coreTAS, is at the D-loop 3'-end. Both these sequences may prevent transcription across the D-loop region, since light and heavy strand transcription is terminated at CSB1 and coreTAS, respectively. Interestingly, the replication of the nascent D-loop strand, occurring in a direction opposite to that of heavy strand transcription, is also terminated at coreTAS, suggesting that coreTAS is involved in termination of both transcription and replication. Finally, we demonstrate that the loading of the helicase TWINKLE at coreTAS is reversible, implying that this site is a crucial component of a switch between D-loop formation and full-length mitochondrial DNA replication.
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Affiliation(s)
- Elisabeth Jemt
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Örjan Persson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Yonghong Shi
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Majda Mehmedovic
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Jay P Uhler
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Marcela Dávila López
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Christoph Freyer
- Department of Laboratory Medicine, Karolinska Institutet, Retzius väg 8, 171 77 Stockholm, Sweden
| | - Claes M Gustafsson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Tore Samuelsson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, P.O. Box 440, SE-405 30 Gothenburg, Sweden
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43
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Ahmed N, Ronchi D, Comi GP. Genes and Pathways Involved in Adult Onset Disorders Featuring Muscle Mitochondrial DNA Instability. Int J Mol Sci 2015; 16:18054-76. [PMID: 26251896 PMCID: PMC4581235 DOI: 10.3390/ijms160818054] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 07/27/2015] [Accepted: 07/28/2015] [Indexed: 12/31/2022] Open
Abstract
Replication and maintenance of mtDNA entirely relies on a set of proteins encoded by the nuclear genome, which include members of the core replicative machinery, proteins involved in the homeostasis of mitochondrial dNTPs pools or deputed to the control of mitochondrial dynamics and morphology. Mutations in their coding genes have been observed in familial and sporadic forms of pediatric and adult-onset clinical phenotypes featuring mtDNA instability. The list of defects involved in these disorders has recently expanded, including mutations in the exo-/endo-nuclease flap-processing proteins MGME1 and DNA2, supporting the notion that an enzymatic DNA repair system actively takes place in mitochondria. The results obtained in the last few years acknowledge the contribution of next-generation sequencing methods in the identification of new disease loci in small groups of patients and even single probands. Although heterogeneous, these genes can be conveniently classified according to the pathway to which they belong. The definition of the molecular and biochemical features of these pathways might be helpful for fundamental knowledge of these disorders, to accelerate genetic diagnosis of patients and the development of rational therapies. In this review, we discuss the molecular findings disclosed in adult patients with muscle pathology hallmarked by mtDNA instability.
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Affiliation(s)
- Naghia Ahmed
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, via Francesco Sforza 35, Milan 20122, Italy.
| | - Dario Ronchi
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, via Francesco Sforza 35, Milan 20122, Italy.
| | - Giacomo Pietro Comi
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, via Francesco Sforza 35, Milan 20122, Italy.
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44
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Stewart JB, Alaei-Mahabadi B, Sabarinathan R, Samuelsson T, Gorodkin J, Gustafsson CM, Larsson E. Simultaneous DNA and RNA Mapping of Somatic Mitochondrial Mutations across Diverse Human Cancers. PLoS Genet 2015; 11:e1005333. [PMID: 26125550 PMCID: PMC4488357 DOI: 10.1371/journal.pgen.1005333] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/03/2015] [Indexed: 12/30/2022] Open
Abstract
Somatic mutations in the nuclear genome are required for tumor formation, but the functional consequences of somatic mitochondrial DNA (mtDNA) mutations are less understood. Here we identify somatic mtDNA mutations across 527 tumors and 14 cancer types, using an approach that takes advantage of evidence from both genomic and transcriptomic sequencing. We find that there is selective pressure against deleterious coding mutations, supporting that functional mitochondria are required in tumor cells, and also observe a strong mutational strand bias, compatible with endogenous replication-coupled errors as the major source of mutations. Interestingly, while allelic ratios in general were consistent in RNA compared to DNA, some mutations in tRNAs displayed strong allelic imbalances caused by accumulation of unprocessed tRNA precursors. The effect was explained by altered secondary structure, demonstrating that correct tRNA folding is a major determinant for processing of polycistronic mitochondrial transcripts. Additionally, the data suggest that tRNA clusters are preferably processed in the 3′ to 5′ direction. Our study gives insights into mtDNA function in cancer and answers questions regarding mitochondrial tRNA biogenesis that are difficult to address in controlled experimental systems. According to the so-called “tRNA punctuation model”, tRNA processing is key to generating all mature mitochondrial mRNAs. However, the process is difficult to study in vivo, since standard tools for genetic manipulation are not applicable to mitochondria. Here, we circumvent this problem by using a large compendium of naturally occurring genetic perturbations, derived from human tumor sequencing data. We identify somatic mitochondrial mutations across hundreds of human tumors using an approach that simultaneously takes advantage of both genomic and transcriptomic sequencing. This enables us to compare the allele frequency in DNA and RNA for each mutation. Our data reveals that some mutations in mitochondrial tRNAs are associated with strong accumulation of immature tRNA precursors, indicative of impaired tRNA mutaration. We find that intact tRNA secondary structure is a major requirement for correct maturation, and that mutations affecting tRNA folding can impair maturation of not only the affected tRNA, but also neighboring gene transcripts. Mutations in mitochondrial tRNAs underlie a range of disease conditions, and our findings may help to explain why mutations in the same tRNA can present different phenotypes. Our results additionally support that there is selective pressure against mutations affecting oxidative phosphorylation, showing that functional mitochondria are required in many tumor cells.
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Affiliation(s)
| | - Babak Alaei-Mahabadi
- Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Radhakrishnan Sabarinathan
- Center for non-coding RNA in Technology and Health, IKVH, University of Copenhagen, Frederiksberg, Denmark
| | - Tore Samuelsson
- Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Jan Gorodkin
- Center for non-coding RNA in Technology and Health, IKVH, University of Copenhagen, Frederiksberg, Denmark
| | - Claes M. Gustafsson
- Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Erik Larsson
- Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- * E-mail:
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45
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Salama M, Mohamed WM. NDUFA12L mitochondrial complex-I assembly factor: Implications for taupathies. Appl Transl Genom 2015; 5:37-9. [PMID: 26937358 PMCID: PMC4745364 DOI: 10.1016/j.atg.2015.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 05/29/2015] [Indexed: 12/02/2022]
Abstract
There is a strong correlation between taupathies and the development and progression of neurodegenerative disorders. Abnormal tau becomes hyperphosphorylated and dissociated from microtubules with the aggregation of intracellular tau aggregates within the patient's brain. The current review is divided into two broad sections. In the first section we discuss the molecular biology and the clinicopathologic features of taupathies. While in the second section we discuss the relationship between mitochondrial complex-I and taupathies. Polymorphism in NDUFA12L may be a crucial factor for development of neurodegenerative taupathies. Thus NDUFA12L screening may be an early biomarker for identifying risk groups for such disorders.
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Affiliation(s)
| | - Wael M.Y. Mohamed
- Clinical Pharmacology Dept, Menoufia Medical School, Menoufia University, Egypt
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46
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Szczepanowska K, Trifunovic A. Different faces of mitochondrial DNA mutators. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1362-72. [PMID: 26014346 DOI: 10.1016/j.bbabio.2015.05.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 05/15/2015] [Accepted: 05/17/2015] [Indexed: 10/23/2022]
Abstract
A number of studies have shown that ageing is associated with increased amounts of mtDNA deletions and/or point mutations in a variety of species as diverse as Caenorhabditis elegans, Drosophila melanogaster, mice, rats, dogs, primates and humans. This detected vulnerability of mtDNA has led to the suggestion that the accumulation of somatic mtDNA mutations might arise from increased oxidative damage and could play an important role in the ageing process by producing cells with a decreased oxidative capacity. However, the vast majority of DNA polymorphisms and disease-causing base-substitution mutations and age-associated mutations that have been detected in human mtDNA are transition mutations. They are likely arising from the slight infidelity of the mitochondrial DNA polymerase. Indeed, transition mutations are also the predominant type of mutation found in mtDNA mutator mice, a model for premature ageing caused by increased mutation load due to the error prone mitochondrial DNA synthesis. These particular misincorporation events could also be exacerbated by dNTP pool imbalances. The role of different repair, replication and maintenance mechanisms that contribute to mtDNA integrity and mutagenesis will be discussed in details in this article. This article is part of a Special Issue entitled: Mitochondrial Dysfunction in Aging.
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Affiliation(s)
- Karolina Szczepanowska
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931 Cologne, Germany
| | - Aleksandra Trifunovic
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931 Cologne, Germany.
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47
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Tan K, Fujimoto M, Takii R, Takaki E, Hayashida N, Nakai A. Mitochondrial SSBP1 protects cells from proteotoxic stresses by potentiating stress-induced HSF1 transcriptional activity. Nat Commun 2015; 6:6580. [PMID: 25762445 PMCID: PMC4558571 DOI: 10.1038/ncomms7580] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 02/09/2015] [Indexed: 12/13/2022] Open
Abstract
Heat-shock response is an adaptive response to proteotoxic stresses including heat shock, and is regulated by heat-shock factor 1 (HSF1) in mammals. Proteotoxic stresses challenge all subcellular compartments including the mitochondria. Therefore, there must be close connections between mitochondrial signals and the activity of HSF1. Here, we show that heat shock triggers nuclear translocation of mitochondrial SSBP1, which is involved in replication of mitochondrial DNA, in a manner dependent on the mitochondrial permeability transition pore ANT–VDAC1 complex and direct interaction with HSF1. HSF1 recruits SSBP1 to the promoters of genes encoding cytoplasmic/nuclear and mitochondrial chaperones. HSF1–SSBP1 complex then enhances their induction by facilitating the recruitment of a chromatin-remodelling factor BRG1, and supports cell survival and the maintenance of mitochondrial membrane potential against proteotoxic stresses. These results suggest that the nuclear translocation of mitochondrial SSBP1 is required for the regulation of cytoplasmic/nuclear and mitochondrial proteostasis against proteotoxic stresses. Heat shock induces proteotoxic stress, and the cellular response is mediated by heat-shock factor 1 (HSF1). Here, Tan et al. show that following heat shock, mitochondrial SSBP1 translocates to the nucleus and binds HSF1 to enhance the expression of chaperones and support the maintenance of mitochondrial function.
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Affiliation(s)
- Ke Tan
- Department of Biochemistry and Molecular Biology, Yamaguchi University School of Medicine, Minami-Kogushi 1-1-1, Ube 755-8505, Japan
| | - Mitsuaki Fujimoto
- Department of Biochemistry and Molecular Biology, Yamaguchi University School of Medicine, Minami-Kogushi 1-1-1, Ube 755-8505, Japan
| | - Ryosuke Takii
- Department of Biochemistry and Molecular Biology, Yamaguchi University School of Medicine, Minami-Kogushi 1-1-1, Ube 755-8505, Japan
| | - Eiichi Takaki
- Department of Biochemistry and Molecular Biology, Yamaguchi University School of Medicine, Minami-Kogushi 1-1-1, Ube 755-8505, Japan
| | - Naoki Hayashida
- Department of Biochemistry and Molecular Biology, Yamaguchi University School of Medicine, Minami-Kogushi 1-1-1, Ube 755-8505, Japan
| | - Akira Nakai
- Department of Biochemistry and Molecular Biology, Yamaguchi University School of Medicine, Minami-Kogushi 1-1-1, Ube 755-8505, Japan
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48
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Clausen AR, Lujan SA, Burkholder AB, Orebaugh CD, Williams JS, Clausen MF, Malc EP, Mieczkowski PA, Fargo DC, Smith DJ, Kunkel TA. Tracking replication enzymology in vivo by genome-wide mapping of ribonucleotide incorporation. Nat Struct Mol Biol 2015; 22:185-91. [PMID: 25622295 PMCID: PMC4351163 DOI: 10.1038/nsmb.2957] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 12/18/2014] [Indexed: 12/12/2022]
Abstract
Ribonucleotides are frequently incorporated into DNA during replication in eukaryotes. Here we map genome-wide distribution of these ribonucleotides as markers of replication enzymology in budding yeast, using a new 5' DNA end-mapping method, hydrolytic end sequencing (HydEn-seq). HydEn-seq of DNA from ribonucleotide excision repair-deficient strains reveals replicase- and strand-specific patterns of ribonucleotides in the nuclear genome. These patterns support the roles of DNA polymerases α and δ in lagging-strand replication and of DNA polymerase ɛ in leading-strand replication. They identify replication origins, termination zones and variations in ribonucleotide incorporation frequency across the genome that exceed three orders of magnitude. HydEn-seq also reveals strand-specific 5' DNA ends at mitochondrial replication origins, thus suggesting unidirectional replication of a circular genome. Given the conservation of enzymes that incorporate and process ribonucleotides in DNA, HydEn-seq can be used to track replication enzymology in other organisms.
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Affiliation(s)
- Anders R Clausen
- Genome Integrity &Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institute of Health (NIH), Research Triangle Park, North Carolina, USA
| | - Scott A Lujan
- Genome Integrity &Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institute of Health (NIH), Research Triangle Park, North Carolina, USA
| | - Adam B Burkholder
- Integrative Bioinformatics, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina, USA
| | - Clinton D Orebaugh
- Genome Integrity &Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institute of Health (NIH), Research Triangle Park, North Carolina, USA
| | - Jessica S Williams
- Genome Integrity &Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institute of Health (NIH), Research Triangle Park, North Carolina, USA
| | - Maryam F Clausen
- Department of Genetics, High Throughput Sequencing Facility, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Ewa P Malc
- Department of Genetics, High Throughput Sequencing Facility, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Piotr A Mieczkowski
- Department of Genetics, High Throughput Sequencing Facility, University of North Carolina, Chapel Hill, North Carolina, USA
| | - David C Fargo
- Integrative Bioinformatics, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, North Carolina, USA
| | - Duncan J Smith
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, New York, USA
| | - Thomas A Kunkel
- Genome Integrity &Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institute of Health (NIH), Research Triangle Park, North Carolina, USA
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49
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Generating Mouse Models of Mitochondrial Disease. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00043-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] Open
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50
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Jalles A, Maciel P. The disruption of proteostasis in neurodegenerative disorders. AIMS MOLECULAR SCIENCE 2015. [DOI: 10.3934/molsci.2015.3.259] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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