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Rubalcava-Gracia D, Bubb K, Levander F, Burr SP, August AV, Chinnery PF, Koolmeister C, Larsson NG. LRPPRC and SLIRP synergize to maintain sufficient and orderly mammalian mitochondrial translation. Nucleic Acids Res 2024:gkae662. [PMID: 39087558 DOI: 10.1093/nar/gkae662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 07/15/2024] [Accepted: 07/18/2024] [Indexed: 08/02/2024] Open
Abstract
In mammals, the leucine-rich pentatricopeptide repeat protein (LRPPRC) and the stem-loop interacting RNA-binding protein (SLIRP) form a complex in the mitochondrial matrix that is required throughout the life cycle of most mitochondrial mRNAs. Although pathogenic mutations in the LRPPRC and SLIRP genes cause devastating human mitochondrial diseases, the in vivo function of the corresponding proteins is incompletely understood. We show here that loss of SLIRP in mice causes a decrease of complex I levels whereas other OXPHOS complexes are unaffected. We generated knock-in mice to study the in vivo interdependency of SLIRP and LRPPRC by mutating specific amino acids necessary for protein complex formation. When protein complex formation is disrupted, LRPPRC is partially degraded and SLIRP disappears. Livers from Lrpprc knock-in mice had impaired mitochondrial translation except for a marked increase in the synthesis of ATP8. Furthermore, the introduction of a heteroplasmic pathogenic mtDNA mutation (m.C5024T of the tRNAAla gene) into Slirp knockout mice causes an additive effect on mitochondrial translation leading to embryonic lethality and reduced growth of mouse embryonic fibroblasts. To summarize, we report that the LRPPRC/SLIRP protein complex is critical for maintaining normal complex I levels and that it also coordinates mitochondrial translation in a tissue-specific manner.
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Affiliation(s)
- Diana Rubalcava-Gracia
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Kristina Bubb
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Fredrik Levander
- Department en Immunotechnology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Lund University, Lund, Sweden
| | - Stephen P Burr
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK; Medical Research Council Mitochondrial Biology Unit,University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Amelie V August
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Patrick F Chinnery
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK; Medical Research Council Mitochondrial Biology Unit,University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Camilla Koolmeister
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Nils-Göran Larsson
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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2
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Hu W, Yang J, Hu K, Luo G, Chen Z, Lu Z, Li Y, Lv X, Zhao J, Xu C. Identification of TEFM as a potential therapeutic target for LUAD treatment. J Transl Med 2024; 22:692. [PMID: 39075464 PMCID: PMC11288054 DOI: 10.1186/s12967-024-05483-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 07/03/2024] [Indexed: 07/31/2024] Open
Abstract
BACKGROUND Molecularly targeted therapies have recently become a hotspot in the treatment of LUAD, with ongoing efforts to identify new effective targets due to individual variability. Among these potential targets, the mitochondrial transcription elongation factor (TEFM) stands out as a crucial molecule involved in mitochondrial synthetic transcriptional processing. Dysregulation of TEFM has been implicated in the development of various diseases; however, its specific role in LUAD remains unclear. METHODS We conducted a comprehensive analysis of TEFM expression in LUAD, leveraging data from the TCGA database. Subsequently, we validated these findings using clinical specimens obtained from the First Affiliated Hospital of Soochow University, employing western blotting and qRT-PCR techniques. Further experimental validation was performed through the transfection of cells with TEFM overexpression, knockdown, and knockout lentiviruses. The effects of TEFM on LUAD were evaluated both in vitro and in vivo using a range of assays, including CCK-8, colony formation, EdU incorporation, Transwell migration, Tunel assay, flow cytometry, JC-1 staining, and xenograft tumour models. RESULTS Our investigation uncovered that TEFM exhibited elevated expression levels in LUAD and exhibited co-localization with mitochondria. Overexpression of TEFM facilitated malignant processes in LUAD cells, whereas its silencing notably curbed these behaviors and induced mitochondrial depolarization, along with ROS production, culminating in apoptosis. Moreover, the absence of TEFM substantially influenced the expression of mitochondrial transcripts and respiratory chain complexes. Results from nude mouse xenograft tumors further validated that inhibiting TEFM expression markedly hindered tumor growth. CONCLUSION TEFM promotes LUAD malignant progression through the EMT pathway and determines apoptosis by affecting the expression of mitochondrial transcripts and respiratory chain complexes, providing a new therapeutic direction for LUAD-targeted therapy.
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Affiliation(s)
- Wenxuan Hu
- Institute of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
- Department of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Jian Yang
- Institute of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
- Department of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Kang Hu
- Institute of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
- Department of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Gaomeng Luo
- Institute of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
- Department of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Zhike Chen
- Institute of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
- Department of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Zihao Lu
- Institute of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
- Department of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Yongsen Li
- Institute of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
- Department of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Xin Lv
- Institute of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
- Department of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Jun Zhao
- Institute of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China.
- Department of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China.
| | - Chun Xu
- Institute of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China.
- Department of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China.
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3
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Liu Y, Liu H, Zhang F, Xu H. The initiation of mitochondrial DNA replication. Biochem Soc Trans 2024; 52:1243-1251. [PMID: 38884788 PMCID: PMC11346463 DOI: 10.1042/bst20230952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 05/31/2024] [Accepted: 06/04/2024] [Indexed: 06/18/2024]
Abstract
Mitochondrial DNA replication is initiated by the transcription of mitochondrial RNA polymerase (mtRNAP), as mitochondria lack a dedicated primase. However, the mechanism determining the switch between continuous transcription and premature termination to generate RNA primers for mitochondrial DNA (mtDNA) replication remains unclear. The pentatricopeptide repeat domain of mtRNAP exhibits exoribonuclease activity, which is required for the initiation of mtDNA replication in Drosophila. In this review, we explain how this exonuclease activity contributes to primer synthesis in strand-coupled mtDNA replication, and discuss how its regulation might co-ordinate mtDNA replication and transcription in both Drosophila and mammals.
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Affiliation(s)
- Yi Liu
- Hubei Jiangxia Laboratory, Wuhan 430200, China
| | - Haibin Liu
- Hubei Jiangxia Laboratory, Wuhan 430200, China
| | - Fan Zhang
- National Heart, Lung and Blood Institute, NIH, Bethesda, MD 20892, U.S.A
| | - Hong Xu
- National Heart, Lung and Blood Institute, NIH, Bethesda, MD 20892, U.S.A
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4
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Bernardino Gomes TM, Vincent AE, Menger KE, Stewart JB, Nicholls TJ. Mechanisms and pathologies of human mitochondrial DNA replication and deletion formation. Biochem J 2024; 481:683-715. [PMID: 38804971 PMCID: PMC11346376 DOI: 10.1042/bcj20230262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 05/29/2024]
Abstract
Human mitochondria possess a multi-copy circular genome, mitochondrial DNA (mtDNA), that is essential for cellular energy metabolism. The number of copies of mtDNA per cell, and their integrity, are maintained by nuclear-encoded mtDNA replication and repair machineries. Aberrant mtDNA replication and mtDNA breakage are believed to cause deletions within mtDNA. The genomic location and breakpoint sequences of these deletions show similar patterns across various inherited and acquired diseases, and are also observed during normal ageing, suggesting a common mechanism of deletion formation. However, an ongoing debate over the mechanism by which mtDNA replicates has made it difficult to develop clear and testable models for how mtDNA rearrangements arise and propagate at a molecular and cellular level. These deletions may impair energy metabolism if present in a high proportion of the mtDNA copies within the cell, and can be seen in primary mitochondrial diseases, either in sporadic cases or caused by autosomal variants in nuclear-encoded mtDNA maintenance genes. These mitochondrial diseases have diverse genetic causes and multiple modes of inheritance, and show notoriously broad clinical heterogeneity with complex tissue specificities, which further makes establishing genotype-phenotype relationships challenging. In this review, we aim to cover our current understanding of how the human mitochondrial genome is replicated, the mechanisms by which mtDNA replication and repair can lead to mtDNA instability in the form of large-scale rearrangements, how rearranged mtDNAs subsequently accumulate within cells, and the pathological consequences when this occurs.
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Affiliation(s)
- Tiago M. Bernardino Gomes
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- NHS England Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE2 4HH, U.K
| | - Amy E. Vincent
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - Katja E. Menger
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - James B. Stewart
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - Thomas J. Nicholls
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
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5
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Meynier V, Hardwick SW, Catala M, Roske JJ, Oerum S, Chirgadze DY, Barraud P, Yue WW, Luisi BF, Tisné C. Structural basis for human mitochondrial tRNA maturation. Nat Commun 2024; 15:4683. [PMID: 38824131 PMCID: PMC11144196 DOI: 10.1038/s41467-024-49132-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 05/21/2024] [Indexed: 06/03/2024] Open
Abstract
The human mitochondrial genome is transcribed into two RNAs, containing mRNAs, rRNAs and tRNAs, all dedicated to produce essential proteins of the respiratory chain. The precise excision of tRNAs by the mitochondrial endoribonucleases (mt-RNase), P and Z, releases all RNA species from the two RNA transcripts. The tRNAs then undergo 3'-CCA addition. In metazoan mitochondria, RNase P is a multi-enzyme assembly that comprises the endoribonuclease PRORP and a tRNA methyltransferase subcomplex. The requirement for this tRNA methyltransferase subcomplex for mt-RNase P cleavage activity, as well as the mechanisms of pre-tRNA 3'-cleavage and 3'-CCA addition, are still poorly understood. Here, we report cryo-EM structures that visualise four steps of mitochondrial tRNA maturation: 5' and 3' tRNA-end processing, methylation and 3'-CCA addition, and explain the defined sequential order of the tRNA processing steps. The methyltransferase subcomplex recognises the pre-tRNA in a distinct mode that can support tRNA-end processing and 3'-CCA addition, likely resulting from an evolutionary adaptation of mitochondrial tRNA maturation complexes to the structurally-fragile mitochondrial tRNAs. This subcomplex can also ensure a tRNA-folding quality-control checkpoint before the sequential docking of the maturation enzymes. Altogether, our study provides detailed molecular insight into RNA-transcript processing and tRNA maturation in human mitochondria.
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Affiliation(s)
- Vincent Meynier
- Expression Génétique Microbienne, Université Paris Cité, CNRS, Institut de Biologie Physico-Chimique (IBPC), 75005, Paris, France
| | - Steven W Hardwick
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Marjorie Catala
- Expression Génétique Microbienne, Université Paris Cité, CNRS, Institut de Biologie Physico-Chimique (IBPC), 75005, Paris, France
| | - Johann J Roske
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Stephanie Oerum
- Expression Génétique Microbienne, Université Paris Cité, CNRS, Institut de Biologie Physico-Chimique (IBPC), 75005, Paris, France
| | - Dimitri Y Chirgadze
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Pierre Barraud
- Expression Génétique Microbienne, Université Paris Cité, CNRS, Institut de Biologie Physico-Chimique (IBPC), 75005, Paris, France
| | - Wyatt W Yue
- Centre for Medicines Discovery, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, OX3 7DQ, UK
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Ben F Luisi
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Carine Tisné
- Expression Génétique Microbienne, Université Paris Cité, CNRS, Institut de Biologie Physico-Chimique (IBPC), 75005, Paris, France.
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6
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McShane E, Churchman LS. Central dogma rates in human mitochondria. Hum Mol Genet 2024; 33:R34-R41. [PMID: 38779776 PMCID: PMC11112385 DOI: 10.1093/hmg/ddae036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 12/28/2023] [Accepted: 02/29/2024] [Indexed: 05/25/2024] Open
Abstract
In human cells, the nuclear and mitochondrial genomes engage in a complex interplay to produce dual-encoded oxidative phosphorylation (OXPHOS) complexes. The coordination of these dynamic gene expression processes is essential for producing matched amounts of OXPHOS protein subunits. This review focuses on our current understanding of the mitochondrial central dogma rates, highlighting the striking differences in gene expression rates between mitochondrial and nuclear genes. We synthesize a coherent model of mitochondrial gene expression kinetics, highlighting the emerging principles and emphasizing where more precise measurements would be beneficial. Such an understanding is pivotal for grasping the unique aspects of mitochondrial function and its role in cellular energetics, and it has profound implications for aging, metabolic disorders, and neurodegenerative diseases.
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Affiliation(s)
- Erik McShane
- Department of Genetics, Blavatnik Institute, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, United States
| | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, United States
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7
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Hughes LA, Rackham O, Filipovska A. Illuminating mitochondrial translation through mouse models. Hum Mol Genet 2024; 33:R61-R79. [PMID: 38779771 PMCID: PMC11112386 DOI: 10.1093/hmg/ddae020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/22/2024] [Accepted: 01/31/2024] [Indexed: 05/25/2024] Open
Abstract
Mitochondria are hubs of metabolic activity with a major role in ATP conversion by oxidative phosphorylation (OXPHOS). The mammalian mitochondrial genome encodes 11 mRNAs encoding 13 OXPHOS proteins along with 2 rRNAs and 22 tRNAs, that facilitate their translation on mitoribosomes. Maintaining the internal production of core OXPHOS subunits requires modulation of the mitochondrial capacity to match the cellular requirements and correct insertion of particularly hydrophobic proteins into the inner mitochondrial membrane. The mitochondrial translation system is essential for energy production and defects result in severe, phenotypically diverse diseases, including mitochondrial diseases that typically affect postmitotic tissues with high metabolic demands. Understanding the complex mechanisms that underlie the pathologies of diseases involving impaired mitochondrial translation is key to tailoring specific treatments and effectively targeting the affected organs. Disease mutations have provided a fundamental, yet limited, understanding of mitochondrial protein synthesis, since effective modification of the mitochondrial genome has proven challenging. However, advances in next generation sequencing, cryoelectron microscopy, and multi-omic technologies have revealed unexpected and unusual features of the mitochondrial protein synthesis machinery in the last decade. Genome editing tools have generated unique models that have accelerated our mechanistic understanding of mitochondrial translation and its physiological importance. Here we review the most recent mouse models of disease pathogenesis caused by defects in mitochondrial protein synthesis and discuss their value for preclinical research and therapeutic development.
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Affiliation(s)
- Laetitia A Hughes
- Telethon Kids Institute, Northern Entrance, Perth Children’s Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
- Harry Perkins Institute of Medical Research, 6 Verdun Street, Nedlands, WA 6009, Australia
- ARC Centre of Excellence in Synthetic Biology, 35 Stirling Highway, Crawley, WA 6009, The University of Western Australia, Crawley, WA 6009, Australia
| | - Oliver Rackham
- Telethon Kids Institute, Northern Entrance, Perth Children’s Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
- Harry Perkins Institute of Medical Research, 6 Verdun Street, Nedlands, WA 6009, Australia
- ARC Centre of Excellence in Synthetic Biology, 35 Stirling Highway, Crawley, WA 6009, The University of Western Australia, Crawley, WA 6009, Australia
- Curtin Medical School, Curtin University, Kent Street, Bentley, WA 6102, Australia
- Curtin Health Innovation Research Institute, Curtin University, Kent Street, Bentley, WA 6102, Australia
| | - Aleksandra Filipovska
- Telethon Kids Institute, Northern Entrance, Perth Children’s Hospital, 15 Hospital Avenue, Nedlands, WA 6009, Australia
- ARC Centre of Excellence in Synthetic Biology, 35 Stirling Highway, Crawley, WA 6009, The University of Western Australia, Crawley, WA 6009, Australia
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, 19 Innovation Walk, Clayton, Clayton, VIC 3168, Australia
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8
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Sovilj D, Kelemen CD, Dvorakova S, Zobalova R, Raabova H, Kriska J, Hermanova Z, Knotek T, Anderova M, Klener P, Filimonenko V, Neuzil J, Andera L. Cell-specific modulation of mitochondrial respiration and metabolism by the pro-apoptotic Bcl-2 family members Bax and Bak. Apoptosis 2024; 29:424-438. [PMID: 38001340 DOI: 10.1007/s10495-023-01917-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2023] [Indexed: 11/26/2023]
Abstract
Proteins from the Bcl-2 family play an essential role in the regulation of apoptosis. However, they also possess cell death-unrelated activities that are less well understood. This prompted us to study apoptosis-unrelated activities of the Bax and Bak, pro-apoptotic members of the Bcl-2 family. We prepared Bax/Bak-deficient human cancer cells of different origin and found that while respiration in the glioblastoma U87 Bax/Bak-deficient cells was greatly enhanced, respiration of Bax/Bak-deficient B lymphoma HBL-2 cells was slightly suppressed. Bax/Bak-deficient U87 cells also proliferated faster in culture, formed tumours more rapidly in mice, and showed modulation of metabolism with a considerably increased NAD+/NADH ratio. Follow-up analyses documented increased/decreased expression of mitochondria-encoded subunits of respiratory complexes and stabilization/destabilization of the mitochondrial transcription elongation factor TEFM in Bax/Bak-deficient U87 and HBL-2 cells, respectively. TEFM downregulation using shRNAs attenuated mitochondrial respiration in Bax/Bak-deficient U87 as well as in parental HBL-2 cells. We propose that (post)translational regulation of TEFM levels in Bax/Bak-deficient cells modulates levels of subunits of mitochondrial respiratory complexes that, in turn, contribute to respiration and the accompanying changes in metabolism and proliferation in these cells.
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Affiliation(s)
- Dana Sovilj
- Institute of Biotechnology, Czech Academy of Sciences, Vestec, Prague, Czech Republic
| | - Cristina Daniela Kelemen
- Institute of Biotechnology, Czech Academy of Sciences, Vestec, Prague, Czech Republic
- Faculty of Science, Charles University, Prague, Czech Republic
| | - Sarka Dvorakova
- Institute of Biotechnology, Czech Academy of Sciences, Vestec, Prague, Czech Republic
| | - Renata Zobalova
- Institute of Biotechnology, Czech Academy of Sciences, Vestec, Prague, Czech Republic
| | - Helena Raabova
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Kriska
- Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czech Republic
| | - Zuzana Hermanova
- Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czech Republic
| | - Tomas Knotek
- Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czech Republic
| | - Miroslava Anderova
- Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czech Republic
| | - Pavel Klener
- First Faculty of Medicine, Institute of Pathological Physiology, Charles University, Prague, Czech Republic
| | - Vlada Filimonenko
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Jiri Neuzil
- Institute of Biotechnology, Czech Academy of Sciences, Vestec, Prague, Czech Republic
- Faculty of Science, Charles University, Prague, Czech Republic
- First Faculty of Medicine, Charles University, Prague, Czech Republic
- School of Pharmacy and Medical Science, Griffith University, Southport, QLD, Australia
| | - Ladislav Andera
- Institute of Biotechnology, Czech Academy of Sciences, Vestec, Prague, Czech Republic.
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic.
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9
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Tan BG, Gustafsson CM, Falkenberg M. Mechanisms and regulation of human mitochondrial transcription. Nat Rev Mol Cell Biol 2024; 25:119-132. [PMID: 37783784 DOI: 10.1038/s41580-023-00661-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2023] [Indexed: 10/04/2023]
Abstract
The expression of mitochondrial genes is regulated in response to the metabolic needs of different cell types, but the basic mechanisms underlying this process are still poorly understood. In this Review, we describe how different layers of regulation cooperate to fine tune initiation of both mitochondrial DNA (mtDNA) transcription and replication in human cells. We discuss our current understanding of the molecular mechanisms that drive and regulate transcription initiation from mtDNA promoters, and how the packaging of mtDNA into nucleoids can control the number of mtDNA molecules available for both transcription and replication. Indeed, a unique aspect of the mitochondrial transcription machinery is that it is coupled to mtDNA replication, such that mitochondrial RNA polymerase is additionally required for primer synthesis at mtDNA origins of replication. We discuss how the choice between replication-primer formation and genome-length RNA synthesis is controlled at the main origin of replication (OriH) and how the recent discovery of an additional mitochondrial promoter (LSP2) in humans may change this long-standing model.
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Affiliation(s)
- Benedict G Tan
- Institute for Mitochondrial Diseases and Ageing, Faculty of Medicine and University Hospital Cologne, Cluster of Excellence Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Claes M Gustafsson
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
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10
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Lee RG, Rudler DL, Raven SA, Peng L, Chopin A, Moh ESX, McCubbin T, Siira SJ, Fagan SV, DeBono NJ, Stentenbach M, Browne J, Rackham FF, Li J, Simpson KJ, Marcellin E, Packer NH, Reid GE, Padman BS, Rackham O, Filipovska A. Quantitative subcellular reconstruction reveals a lipid mediated inter-organelle biogenesis network. Nat Cell Biol 2024; 26:57-71. [PMID: 38129691 DOI: 10.1038/s41556-023-01297-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 10/18/2023] [Indexed: 12/23/2023]
Abstract
The structures and functions of organelles in cells depend on each other but have not been systematically explored. We established stable knockout cell lines of peroxisomal, Golgi and endoplasmic reticulum genes identified in a whole-genome CRISPR knockout screen for inducers of mitochondrial biogenesis stress, showing that defects in peroxisome, Golgi and endoplasmic reticulum metabolism disrupt mitochondrial structure and function. Our quantitative total-organelle profiling approach for focussed ion beam scanning electron microscopy revealed in unprecedented detail that specific organelle dysfunctions precipitate multi-organelle biogenesis defects, impair mitochondrial morphology and reduce respiration. Multi-omics profiling showed a unified proteome response and global shifts in lipid and glycoprotein homeostasis that are elicited when organelle biogenesis is compromised, and that the resulting mitochondrial dysfunction can be rescued with precursors for ether-glycerophospholipid metabolic pathways. This work defines metabolic and morphological interactions between organelles and how their perturbation can cause disease.
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Affiliation(s)
- Richard G Lee
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia, Australia
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Danielle L Rudler
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia, Australia
| | - Samuel A Raven
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, Australia
- Curtin Medical School, Curtin University, Bentley, Western Australia, Australia
- Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - Liuyu Peng
- School of Chemistry, The University of Melbourne, Parkville, Victoria, Australia
| | - Anaëlle Chopin
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia, Australia
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Edward S X Moh
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, New South Wales, Australia
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Tim McCubbin
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Queensland, Australia
- ARC Centre of Excellence in Synthetic Biology, The University of Queensland, Queensland, Australia
| | - Stefan J Siira
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia, Australia
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Samuel V Fagan
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia, Australia
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Nicholas J DeBono
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, New South Wales, Australia
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Maike Stentenbach
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia, Australia
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Jasmin Browne
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia, Australia
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Filip F Rackham
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
| | - Ji Li
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia, Australia
| | - Kaylene J Simpson
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
- Victorian Centre for Functional Genomics, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, Victoria, Australia
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Queensland, Australia
- ARC Centre of Excellence in Synthetic Biology, The University of Queensland, Queensland, Australia
| | - Nicolle H Packer
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, New South Wales, Australia
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Gavin E Reid
- School of Chemistry, The University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, Victoria, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Benjamin S Padman
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, Nedlands, Western Australia, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, Australia
| | - Oliver Rackham
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, Australia
- Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia, Australia
- Curtin Medical School, Curtin University, Bentley, Western Australia, Australia
- Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - Aleksandra Filipovska
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, Australia.
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, Nedlands, Western Australia, Australia.
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11
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Kramer NJ, Prakash G, Isaac RS, Choquet K, Soto I, Petrova B, Merens HE, Kanarek N, Churchman LS. Regulators of mitonuclear balance link mitochondrial metabolism to mtDNA expression. Nat Cell Biol 2023; 25:1575-1589. [PMID: 37770567 PMCID: PMC11370000 DOI: 10.1038/s41556-023-01244-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 08/29/2023] [Indexed: 09/30/2023]
Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) complexes are assembled from proteins encoded by both nuclear and mitochondrial DNA. These dual-origin enzymes pose a complex gene regulatory challenge for cells requiring coordinated gene expression across organelles. To identify genes involved in dual-origin protein complex synthesis, we performed fluorescence-activated cell-sorting-based genome-wide screens analysing mutant cells with unbalanced levels of mitochondrial- and nuclear-encoded subunits of Complex IV. We identified genes involved in OXPHOS biogenesis, including two uncharacterized genes: PREPL and NME6. We found that PREPL specifically impacts Complex IV biogenesis by acting at the intersection of mitochondrial lipid metabolism and protein synthesis, whereas NME6, an uncharacterized nucleoside diphosphate kinase, controls OXPHOS biogenesis through multiple mechanisms reliant on its NDPK domain. Firstly, NME6 forms a complex with RCC1L, which together perform nucleoside diphosphate kinase activity to maintain local mitochondrial pyrimidine triphosphate levels essential for mitochondrial RNA abundance. Secondly, NME6 modulates the activity of mitoribosome regulatory complexes, altering mitoribosome assembly and mitochondrial RNA pseudouridylation. Taken together, we propose that NME6 acts as a link between compartmentalized mitochondrial metabolites and mitochondrial gene expression.
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Affiliation(s)
- Nicholas J Kramer
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Gyan Prakash
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - R Stefan Isaac
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Karine Choquet
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Iliana Soto
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Boryana Petrova
- Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Hope E Merens
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Naama Kanarek
- Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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12
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McShane E, Couvillion M, Ietswaart R, Prakash G, Smalec BM, Soto I, Baxter-Koenigs AR, Choquet K, Churchman LS. A kinetic dichotomy between mitochondrial and nuclear gene expression drives OXPHOS biogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.09.527880. [PMID: 36824735 PMCID: PMC9948965 DOI: 10.1101/2023.02.09.527880] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Oxidative phosphorylation (OXPHOS) complexes, encoded by both mitochondrial and nuclear DNA, are essential producers of cellular ATP, but how nuclear and mitochondrial gene expression steps are coordinated to achieve balanced OXPHOS biogenesis remains unresolved. Here, we present a parallel quantitative analysis of the human nuclear and mitochondrial messenger RNA (mt-mRNA) life cycles, including transcript production, processing, ribosome association, and degradation. The kinetic rates of nearly every stage of gene expression differed starkly across compartments. Compared to nuclear mRNAs, mt-mRNAs were produced 700-fold higher, degraded 5-fold faster, and accumulated to 170-fold higher levels. Quantitative modeling and depletion of mitochondrial factors, LRPPRC and FASTKD5, identified critical points of mitochondrial regulatory control, revealing that the mitonuclear expression disparities intrinsically arise from the highly polycistronic nature of human mitochondrial pre-mRNA. We propose that resolving these differences requires a 100-fold slower mitochondrial translation rate, illuminating the mitoribosome as a nexus of mitonuclear co-regulation.
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Affiliation(s)
- Erik McShane
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Mary Couvillion
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Robert Ietswaart
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Gyan Prakash
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Brendan M. Smalec
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Iliana Soto
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | | | - Karine Choquet
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
- Current affiliation: Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - L. Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
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13
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Loguercio Polosa P, Capriglia F, Bruni F. Molecular Investigation of Mitochondrial RNA19 Role in the Pathogenesis of MELAS Disease. Life (Basel) 2023; 13:1863. [PMID: 37763267 PMCID: PMC10532844 DOI: 10.3390/life13091863] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/16/2023] [Accepted: 08/31/2023] [Indexed: 09/29/2023] Open
Abstract
In mammalian mitochondria, the processing of primary RNA transcripts involves a coordinated series of cleavage and modification events, leading to the formation of processing intermediates and mature mt-RNAs. RNA19 is an unusually stable unprocessed precursor, physiologically polyadenylated, which includes the 16S mt-rRNA, the mt-tRNALeuUUR and the mt-ND1 mRNA. These peculiarities, together with the alteration of its steady-state levels in cellular models with defects in mitochondrial function, make RNA19 a potentially important molecule for the physiological regulation of mitochondrial molecular processes as well as for the pathogenesis of mitochondrial diseases. In this work, we quantitatively and qualitatively examined RNA19 in MELAS trans-mitochondrial cybrids carrying the mtDNA 3243A>G transition and displaying a profound mitochondrial translation defect. Through a combination of isokinetic sucrose gradient and RT-qPCR experiments, we found that RNA19 accumulated and co-sedimented with the mitoribosomal large subunit (mt-LSU) in mutant cells. Intriguingly, exogenous expression of the isolated LARS2 C-terminal domain (Cterm), which was shown to rescue defective translation in MELAS cybrids, decreased the levels of mt-LSU-associated RNA19 by relegating it to the pool of free unbound RNAs. Overall, the data reported here support a regulatory role for RNA19 in mitochondrial physiopathological processes, designating this RNA precursor as a possible molecular target in view of therapeutic strategy development.
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Affiliation(s)
| | | | - Francesco Bruni
- Department of Biosciences, Biotechnologies and Environment, University of Bari ‘Aldo Moro’, 70125 Bari, Italy; (P.L.P.); (F.C.)
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14
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Potter A, Hangas A, Goffart S, Huynen MA, Cabrera-Orefice A, Spelbrink JN. Uncharacterized protein C17orf80 - a novel interactor of human mitochondrial nucleoids. J Cell Sci 2023; 136:jcs260822. [PMID: 37401363 PMCID: PMC10445727 DOI: 10.1242/jcs.260822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 06/26/2023] [Indexed: 07/05/2023] Open
Abstract
Molecular functions of many human proteins remain unstudied, despite the demonstrated association with diseases or pivotal molecular structures, such as mitochondrial DNA (mtDNA). This small genome is crucial for the proper functioning of mitochondria, the energy-converting organelles. In mammals, mtDNA is arranged into macromolecular complexes called nucleoids that serve as functional stations for its maintenance and expression. Here, we aimed to explore an uncharacterized protein C17orf80, which was previously detected close to the nucleoid components by proximity labelling mass spectrometry. To investigate the subcellular localization and function of C17orf80, we took advantage of immunofluorescence microscopy, interaction proteomics and several biochemical assays. We demonstrate that C17orf80 is a mitochondrial membrane-associated protein that interacts with nucleoids even when mtDNA replication is inhibited. In addition, we show that C17orf80 is not essential for mtDNA maintenance and mitochondrial gene expression in cultured human cells. These results provide a basis for uncovering the molecular function of C17orf80 and the nature of its association with nucleoids, possibly leading to new insights about mtDNA and its expression.
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Affiliation(s)
- Alisa Potter
- Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
- Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| | - Anu Hangas
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, 80101, Finland
| | - Steffi Goffart
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, 80101, Finland
| | - Martijn A. Huynen
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| | - Alfredo Cabrera-Orefice
- Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| | - Johannes N. Spelbrink
- Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
- Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
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15
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Xing L, Tang Y, Li L, Tao X. ROS in hepatocellular carcinoma: What we know. Arch Biochem Biophys 2023:109699. [PMID: 37499994 DOI: 10.1016/j.abb.2023.109699] [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: 05/25/2023] [Revised: 07/07/2023] [Accepted: 07/21/2023] [Indexed: 07/29/2023]
Abstract
Hepatocellular carcinoma (HCC), which is a primary liver cancer subtype, has a poor prognosis due to its high degree of malignancy. The lack of early diagnosis makes systemic therapy the only hope for HCC patients with advanced disease; however, resistance to drugs is a major obstacle. In recent years, targeted molecular therapy has gained popularity as a potential treatment for HCC. An increase in reactive oxygen species (ROS), which are cancer markers and a potential target for HCC therapy, can both promote and inhibit the disease. At present, many studies have examined targeted regulation of ROS in the treatment of HCC. Here, we reviewed the latest drugs that are still in the experimental stage, including nanocarrier drugs, exosome drugs, antibody drugs, aptamer drugs and polysaccharide drugs, to provide new hope for the clinical treatment of HCC patients.
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Affiliation(s)
- Lin Xing
- Department of Pharmacy, First Affiliated Hospital of Dalian Medical University, Dalian, 116011, China; School of Pharmacy, Dalian Medical University, Dalian, 116044, China
| | - Yuting Tang
- Department of Pharmacy, First Affiliated Hospital of Dalian Medical University, Dalian, 116011, China; School of Pharmacy, Dalian Medical University, Dalian, 116044, China
| | - Lu Li
- Department of Pharmacy, First Affiliated Hospital of Dalian Medical University, Dalian, 116011, China.
| | - Xufeng Tao
- Department of Pharmacy, First Affiliated Hospital of Dalian Medical University, Dalian, 116011, China.
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16
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St John JC, Okada T, Andreas E, Penn A. The role of mtDNA in oocyte quality and embryo development. Mol Reprod Dev 2023; 90:621-633. [PMID: 35986715 PMCID: PMC10952685 DOI: 10.1002/mrd.23640] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/01/2022] [Accepted: 08/08/2022] [Indexed: 09/02/2023]
Abstract
The mitochondrial genome resides in the mitochondria present in nearly all cell types. The porcine (Sus scrofa) mitochondrial genome is circa 16.7 kb in size and exists in the multimeric format in cells. Individual cell types have different numbers of mitochondrial DNA (mtDNA) copy number based on their requirements for ATP produced by oxidative phosphorylation. The oocyte has the largest number of mtDNA of any cell type. During oogenesis, the oocyte sets mtDNA copy number in order that sufficient copies are available to support subsequent developmental events. It also initiates a program of epigenetic patterning that regulates, for example, DNA methylation levels of the nuclear genome. Once fertilized, the nuclear and mitochondrial genomes establish synchrony to ensure that the embryo and fetus can complete each developmental milestone. However, altering the oocyte's mtDNA copy number by mitochondrial supplementation can affect the programming and gene expression profiles of the developing embryo and, in oocytes deficient of mtDNA, it appears to have a positive impact on the embryo development rates and gene expression profiles. Furthermore, mtDNA haplotypes, which define common maternal origins, appear to affect developmental outcomes and certain reproductive traits. Nevertheless, the manipulation of the mitochondrial content of an oocyte might have a developmental advantage.
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Affiliation(s)
- Justin C. St John
- The Mitochondrial Genetics Group, The School of Biomedicine and The Robinson Research InstituteThe University of AdelaideAdelaideSouth AustraliaAustralia
| | - Takashi Okada
- The Mitochondrial Genetics Group, The School of Biomedicine and The Robinson Research InstituteThe University of AdelaideAdelaideSouth AustraliaAustralia
| | - Eryk Andreas
- The Mitochondrial Genetics Group, The School of Biomedicine and The Robinson Research InstituteThe University of AdelaideAdelaideSouth AustraliaAustralia
| | - Alexander Penn
- The Mitochondrial Genetics Group, The School of Biomedicine and The Robinson Research InstituteThe University of AdelaideAdelaideSouth AustraliaAustralia
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17
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Kozhukhar N, Alexeyev MF. 35 Years of TFAM Research: Old Protein, New Puzzles. BIOLOGY 2023; 12:823. [PMID: 37372108 DOI: 10.3390/biology12060823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 05/29/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023]
Abstract
Transcription Factor A Mitochondrial (TFAM), through its contributions to mtDNA maintenance and expression, is essential for cellular bioenergetics and, therefore, for the very survival of cells. Thirty-five years of research on TFAM structure and function generated a considerable body of experimental evidence, some of which remains to be fully reconciled. Recent advancements allowed an unprecedented glimpse into the structure of TFAM complexed with promoter DNA and TFAM within the open promoter complexes. These novel insights, however, raise new questions about the function of this remarkable protein. In our review, we compile the available literature on TFAM structure and function and provide some critical analysis of the available data.
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Affiliation(s)
- Natalya Kozhukhar
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Mikhail F Alexeyev
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL 36688, USA
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18
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Daglish SCD, Fennell EMJ, Graves LM. Targeting Mitochondrial DNA Transcription by POLRMT Inhibition or Depletion as a Potential Strategy for Cancer Treatment. Biomedicines 2023; 11:1598. [PMID: 37371693 PMCID: PMC10295849 DOI: 10.3390/biomedicines11061598] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 05/27/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
Transcription of the mitochondrial genome is essential for the maintenance of oxidative phosphorylation (OXPHOS) and other functions directly related to this unique genome. Considerable evidence suggests that mitochondrial transcription is dysregulated in cancer and cancer metastasis and contributes significantly to cancer cell metabolism. Recently, inhibitors of the mitochondrial DNA-dependent RNA polymerase (POLRMT) were identified as potentially attractive new anti-cancer compounds. These molecules (IMT1, IMT1B) inactivate cancer cell metabolism through reduced transcription of mitochondrially-encoded OXPHOS subunits such as ND1-5 (Complex I) and COI-IV (Complex IV). Studies from our lab have discovered small molecule regulators of the mitochondrial matrix caseinolytic protease (ClpP) as probable inhibitors of mitochondrial transcription. These compounds activate ClpP proteolysis and lead to the rapid depletion of POLRMT and other matrix proteins, resulting in inhibition of mitochondrial transcription and growth arrest. Herein we present a comparison of POLRMT inhibition and ClpP activation, both conceptually and experimentally, and evaluate the results of these treatments on mitochondrial transcription, inhibition of OXPHOS, and ultimately cancer cell growth. We discuss the potential for targeting mitochondrial transcription as a cancer cell vulnerability.
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Affiliation(s)
| | | | - Lee M. Graves
- Department of Pharmacology and the Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (S.C.D.D.); (E.M.J.F.)
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19
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Meurant S, Mauclet L, Dieu M, Arnould T, Eyckerman S, Renard P. Endogenous TOM20 Proximity Labeling: A Swiss-Knife for the Study of Mitochondrial Proteins in Human Cells. Int J Mol Sci 2023; 24:ijms24119604. [PMID: 37298552 DOI: 10.3390/ijms24119604] [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: 04/20/2023] [Revised: 05/24/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023] Open
Abstract
Biotin-based proximity labeling approaches, such as BioID, have demonstrated their use for the study of mitochondria proteomes in living cells. The use of genetically engineered BioID cell lines enables the detailed characterization of poorly characterized processes such as mitochondrial co-translational import. In this process, translation is coupled to the translocation of the mitochondrial proteins, alleviating the energy cost typically associated with the post-translational import relying on chaperone systems. However, the mechanisms are still unclear with only few actors identified but none that have been described in mammals yet. We thus profiled the TOM20 proxisome using BioID, assuming that some of the identified proteins could be molecular actors of the co-translational import in human cells. The obtained results showed a high enrichment of RNA binding proteins close to the TOM complex. However, for the few selected candidates, we could not demonstrate a role in the mitochondrial co-translational import process. Nonetheless, we were able to demonstrate additional uses of our BioID cell line. Indeed, the experimental approach used in this study is thus proposed for the identification of mitochondrial co-translational import effectors and for the monitoring of protein entry inside mitochondria with a potential application in the prediction of mitochondrial protein half-life.
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Affiliation(s)
- Sébastien Meurant
- URBC, Namur Research Institute for Life Sciences (Narilis), University of Namur (UNamur), 5000 Namur, Belgium
| | - Lorris Mauclet
- URBC, Namur Research Institute for Life Sciences (Narilis), University of Namur (UNamur), 5000 Namur, Belgium
| | - Marc Dieu
- Mass Spectrometry Platform (MaSUN), Namur Research Institute for Life Sciences (Narilis), University of Namur (UNamur), 5000 Namur, Belgium
| | - Thierry Arnould
- URBC, Namur Research Institute for Life Sciences (Narilis), University of Namur (UNamur), 5000 Namur, Belgium
| | - Sven Eyckerman
- VIB-UGent Center for Medical Biotechnology, VIB, 9000 Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, 9000 Ghent, Belgium
| | - Patricia Renard
- URBC, Namur Research Institute for Life Sciences (Narilis), University of Namur (UNamur), 5000 Namur, Belgium
- Mass Spectrometry Platform (MaSUN), Namur Research Institute for Life Sciences (Narilis), University of Namur (UNamur), 5000 Namur, Belgium
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20
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Rubalcava-Gracia D, García-Villegas R, Larsson NG. No role for nuclear transcription regulators in mammalian mitochondria? Mol Cell 2023; 83:832-842. [PMID: 36182692 DOI: 10.1016/j.molcel.2022.09.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/17/2022] [Accepted: 09/08/2022] [Indexed: 10/14/2022]
Abstract
Although the mammalian mtDNA transcription machinery is simple and resembles bacteriophage systems, there are many reports that nuclear transcription regulators, as exemplified by MEF2D, MOF, PGC-1α, and hormone receptors, are imported into mammalian mitochondria and directly interact with the mtDNA transcription machinery. However, the supporting experimental evidence for this concept is open to alternate interpretations, and a main issue is the difficulty in distinguishing indirect regulation of mtDNA transcription, caused by altered nuclear gene expression, from direct intramitochondrial effects. We provide a critical discussion and experimental guidelines to stringently assess roles of intramitochondrial factors implicated in direct regulation of mammalian mtDNA transcription.
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Affiliation(s)
- Diana Rubalcava-Gracia
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Rodolfo García-Villegas
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Nils-Göran Larsson
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
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21
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Van Haute L, O'Connor E, Díaz-Maldonado H, Munro B, Polavarapu K, Hock DH, Arunachal G, Athanasiou-Fragkouli A, Bardhan M, Barth M, Bonneau D, Brunetti-Pierri N, Cappuccio G, Caruana NJ, Dominik N, Goel H, Helman G, Houlden H, Lenaers G, Mention K, Murphy D, Nandeesh B, Olimpio C, Powell CA, Preethish-Kumar V, Procaccio V, Rius R, Rebelo-Guiomar P, Simons C, Vengalil S, Zaki MS, Ziegler A, Thorburn DR, Stroud DA, Maroofian R, Christodoulou J, Gustafsson C, Nalini A, Lochmüller H, Minczuk M, Horvath R. TEFM variants impair mitochondrial transcription causing childhood-onset neurological disease. Nat Commun 2023; 14:1009. [PMID: 36823193 PMCID: PMC9950373 DOI: 10.1038/s41467-023-36277-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 01/20/2023] [Indexed: 02/25/2023] Open
Abstract
Mutations in the mitochondrial or nuclear genomes are associated with a diverse group of human disorders characterized by impaired mitochondrial respiration. Within this group, an increasing number of mutations have been identified in nuclear genes involved in mitochondrial RNA biology. The TEFM gene encodes the mitochondrial transcription elongation factor responsible for enhancing the processivity of mitochondrial RNA polymerase, POLRMT. We report for the first time that TEFM variants are associated with mitochondrial respiratory chain deficiency and a wide range of clinical presentations including mitochondrial myopathy with a treatable neuromuscular transmission defect. Mechanistically, we show muscle and primary fibroblasts from the affected individuals have reduced levels of promoter distal mitochondrial RNA transcripts. Finally, tefm knockdown in zebrafish embryos resulted in neuromuscular junction abnormalities and abnormal mitochondrial function, strengthening the genotype-phenotype correlation. Our study highlights that TEFM regulates mitochondrial transcription elongation and its defect results in variable, tissue-specific neurological and neuromuscular symptoms.
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Affiliation(s)
- Lindsey Van Haute
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Emily O'Connor
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, Canada
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, ON, Canada
| | - Héctor Díaz-Maldonado
- Department of Biochemistry and Cell Biology, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Benjamin Munro
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Kiran Polavarapu
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, Canada
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, ON, Canada
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Daniella H Hock
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, VIC, 3052, Australia
| | - Gautham Arunachal
- Department of Human genetics, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Alkyoni Athanasiou-Fragkouli
- UCL London, Department of Neuromuscular Disorders, Institute of Neurology, University College London, London, UK
| | - Mainak Bardhan
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Magalie Barth
- Department of Genetics, Mitovasc INSERM 1083, CNRS 6015, University Hospital of Angers, Angers, France
| | - Dominique Bonneau
- Department of Genetics, Mitovasc INSERM 1083, CNRS 6015, University Hospital of Angers, Angers, France
| | - Nicola Brunetti-Pierri
- Department of Translational Medicine, University of Naples Federico II, Via s. Pansini, 5, 80131, Naples, Italy
| | - Gerarda Cappuccio
- Department of Translational Medicine, University of Naples Federico II, Via s. Pansini, 5, 80131, Naples, Italy
| | - Nikeisha J Caruana
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, VIC, 3052, Australia
- Institute for Health and Sport (IHES), Victoria University, Melbourne, VIC, 3011, Australia
| | - Natalia Dominik
- UCL London, Department of Neuromuscular Disorders, Institute of Neurology, University College London, London, UK
| | - Himanshu Goel
- Hunter Genetics, Waratah, University of Newcastle, Callaghan, NSW, 2298, Australia
| | - Guy Helman
- Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC, 3052, Australia
| | - Henry Houlden
- UCL London, Department of Neuromuscular Disorders, Institute of Neurology, University College London, London, UK
| | - Guy Lenaers
- Department of Genetics, Mitovasc INSERM 1083, CNRS 6015, University Hospital of Angers, Angers, France
| | - Karine Mention
- Pediatric Inherited Metabolic Disorders, Hôpital Jeanne de Flandre, Lille, France
| | - David Murphy
- UCL London, Department of Neuromuscular Disorders, Institute of Neurology, University College London, London, UK
| | - Bevinahalli Nandeesh
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Catarina Olimpio
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | | | | | - Vincent Procaccio
- Department of Genetics, Mitovasc INSERM 1083, CNRS 6015, University Hospital of Angers, Angers, France
| | - Rocio Rius
- Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC, 3052, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, 3010, Australia
| | | | - Cas Simons
- Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC, 3052, Australia
| | - Seena Vengalil
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, 12311, Egypt
| | - Alban Ziegler
- Department of Genetics, Mitovasc INSERM 1083, CNRS 6015, University Hospital of Angers, Angers, France
| | - David R Thorburn
- Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC, 3052, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, 3010, Australia
| | - David A Stroud
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, VIC, 3052, Australia
- Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC, 3052, Australia
| | - Reza Maroofian
- UCL London, Department of Neuromuscular Disorders, Institute of Neurology, University College London, London, UK
| | - John Christodoulou
- Murdoch Children's Research Institute, 50 Flemington Road, Parkville, VIC, 3052, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Claes Gustafsson
- Department of Biochemistry and Cell Biology, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Atchayaram Nalini
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Hanns Lochmüller
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, Canada
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, ON, Canada
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 0XY, UK.
| | - Rita Horvath
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK.
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22
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Park J, Baruch-Torres N, Yin YW. Structural and Molecular Basis for Mitochondrial DNA Replication and Transcription in Health and Antiviral Drug Toxicity. Molecules 2023; 28:1796. [PMID: 36838782 PMCID: PMC9961925 DOI: 10.3390/molecules28041796] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
Human mitochondrial DNA (mtDNA) is a 16.9 kbp double-stranded, circular DNA, encoding subunits of the oxidative phosphorylation electron transfer chain and essential RNAs for mitochondrial protein translation. The minimal human mtDNA replisome is composed of the DNA helicase Twinkle, DNA polymerase γ, and mitochondrial single-stranded DNA-binding protein. While the mitochondrial RNA transcription is carried out by mitochondrial RNA polymerase, mitochondrial transcription factors TFAM and TFB2M, and a transcription elongation factor, TEFM, both RNA transcriptions, and DNA replication machineries are intertwined and control mtDNA copy numbers, cellular energy supplies, and cellular metabolism. In this review, we discuss the mechanisms governing these main pathways and the mtDNA diseases that arise from mutations in transcription and replication machineries from a structural point of view. We also address the adverse effect of antiviral drugs mediated by mitochondrial DNA and RNA polymerases as well as possible structural approaches to develop nucleoside reverse transcriptase inhibitor and ribonucleosides analogs with reduced toxicity.
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Affiliation(s)
- Joon Park
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Noe Baruch-Torres
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Y. Whitney Yin
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA
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23
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Kramer NJ, Prakash G, Choquet K, Soto I, Petrova B, Merens HE, Kanarek N, Churchman LS. Genome-wide screens for mitonuclear co-regulators uncover links between compartmentalized metabolism and mitochondrial gene expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.11.528118. [PMID: 36798306 PMCID: PMC9934615 DOI: 10.1101/2023.02.11.528118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) complexes are assembled from proteins encoded by both nuclear and mitochondrial DNA. These dual-origin enzymes pose a complex gene regulatory challenge for cells, in which gene expression must be coordinated across organelles using distinct pools of ribosomes. How cells produce and maintain the accurate subunit stoichiometries for these OXPHOS complexes remains largely unknown. To identify genes involved in dual-origin protein complex synthesis, we performed FACS-based genome-wide screens analyzing mutant cells with unbalanced levels of mitochondrial- and nuclear-encoded subunits of cytochrome c oxidase (Complex IV). We identified novel genes involved in OXPHOS biogenesis, including two uncharacterized genes: PREPL and NME6 . We found that PREPL specifically regulates Complex IV biogenesis by interacting with mitochondrial protein synthesis machinery, while NME6, an uncharacterized nucleoside diphosphate kinase (NDPK), controls OXPHOS complex biogenesis through multiple mechanisms reliant on its NDPK domain. First, NME6 maintains local mitochondrial pyrimidine triphosphate levels essential for mitochondrial RNA abundance. Second, through stabilizing interactions with RCC1L, NME6 modulates the activity of mitoribosome regulatory complexes, leading to disruptions in mitoribosome assembly and mitochondrial RNA pseudouridylation. Taken together, we propose that NME6 acts as a link between compartmentalized mitochondrial metabolites and mitochondrial gene expression. Finally, we present these screens as a resource, providing a catalog of genes involved in mitonuclear gene regulation and OXPHOS biogenesis.
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24
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Marmolejo-Garza A, Medeiros-Furquim T, Rao R, Eggen BJL, Boddeke E, Dolga AM. Transcriptomic and epigenomic landscapes of Alzheimer's disease evidence mitochondrial-related pathways. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119326. [PMID: 35839870 DOI: 10.1016/j.bbamcr.2022.119326] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 02/06/2023]
Abstract
Alzheimers disease (AD) is the main cause of dementia and it is defined by cognitive decline coupled to extracellular deposit of amyloid-beta protein and intracellular hyperphosphorylation of tau protein. Historically, efforts to target such hallmarks have failed in numerous clinical trials. In addition to these hallmark-targeted approaches, several clinical trials focus on other AD pathological processes, such as inflammation, mitochondrial dysfunction, and oxidative stress. Mitochondria and mitochondrial-related mechanisms have become an attractive target for disease-modifying strategies, as mitochondrial dysfunction prior to clinical onset has been widely described in AD patients and AD animal models. Mitochondrial function relies on both the nuclear and mitochondrial genome. Findings from omics technologies have shed light on AD pathophysiology at different levels (e.g., epigenome, transcriptome and proteome). Most of these studies have focused on the nuclear-encoded components. The first part of this review provides an updated overview of the mechanisms that regulate mitochondrial gene expression and function. The second part of this review focuses on evidence of mitochondrial dysfunction in AD. We have focused on published findings and datasets that study AD. We analyzed published data and provide examples for mitochondrial-related pathways. These pathways are strikingly dysregulated in AD neurons and glia in sex-, cell- and disease stage-specific manners. Analysis of mitochondrial omics data highlights the involvement of mitochondria in AD, providing a rationale for further disease modeling and drug targeting.
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Affiliation(s)
- Alejandro Marmolejo-Garza
- Department of Molecular Pharmacology, Faculty of Science and Engineering, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, the Netherlands; Department of Biomedical Sciences of Cells & Systems, Section Molecular Neurobiology, Faculty of Medical Sciences, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Tiago Medeiros-Furquim
- Department of Molecular Pharmacology, Faculty of Science and Engineering, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, the Netherlands; Department of Biomedical Sciences of Cells & Systems, Section Molecular Neurobiology, Faculty of Medical Sciences, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Ramya Rao
- Department of Molecular Pharmacology, Faculty of Science and Engineering, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, the Netherlands
| | - Bart J L Eggen
- Department of Biomedical Sciences of Cells & Systems, Section Molecular Neurobiology, Faculty of Medical Sciences, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Erik Boddeke
- Department of Biomedical Sciences of Cells & Systems, Section Molecular Neurobiology, Faculty of Medical Sciences, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands; Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen N, Denmark.
| | - Amalia M Dolga
- Department of Molecular Pharmacology, Faculty of Science and Engineering, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, the Netherlands.
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25
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ANGEL2 phosphatase activity is required for non-canonical mitochondrial RNA processing. Nat Commun 2022; 13:5750. [PMID: 36180430 PMCID: PMC9525292 DOI: 10.1038/s41467-022-33368-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 09/14/2022] [Indexed: 11/18/2022] Open
Abstract
Canonical RNA processing in mammalian mitochondria is defined by tRNAs acting as recognition sites for nucleases to release flanking transcripts. The relevant factors, their structures, and mechanism are well described, but not all mitochondrial transcripts are punctuated by tRNAs, and their mode of processing has remained unsolved. Using Drosophila and mouse models, we demonstrate that non-canonical processing results in the formation of 3′ phosphates, and that phosphatase activity by the carbon catabolite repressor 4 domain-containing family member ANGEL2 is required for their hydrolysis. Furthermore, our data suggest that members of the FAST kinase domain-containing protein family are responsible for these 3′ phosphates. Our results therefore propose a mechanism for non-canonical RNA processing in metazoan mitochondria, by identifying the role of ANGEL2. A subset of mitochondrial transcripts is not flanked by tRNAs and thus does not conform to the canonical mode of processing. Here, Clemente et al. demonstrate that phosphatase activity of ANGEL2 is required for correct processing of these transcripts.
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26
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Tan BG, Mutti CD, Shi Y, Xie X, Zhu X, Silva-Pinheiro P, Menger KE, Díaz-Maldonado H, Wei W, Nicholls TJ, Chinnery PF, Minczuk M, Falkenberg M, Gustafsson CM. The human mitochondrial genome contains a second light strand promoter. Mol Cell 2022; 82:3646-3660.e9. [PMID: 36044900 DOI: 10.1016/j.molcel.2022.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/21/2022] [Accepted: 08/07/2022] [Indexed: 11/30/2022]
Abstract
The human mitochondrial genome must be replicated and expressed in a timely manner to maintain energy metabolism and supply cells with adequate levels of adenosine triphosphate. Central to this process is the idea that replication primers and gene products both arise via transcription from a single light strand promoter (LSP) such that primer formation can influence gene expression, with no consensus as to how this is regulated. Here, we report the discovery of a second light strand promoter (LSP2) in humans, with features characteristic of a bona fide mitochondrial promoter. We propose that the position of LSP2 on the mitochondrial genome allows replication and gene expression to be orchestrated from two distinct sites, which expands our long-held understanding of mitochondrial gene expression in humans.
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Affiliation(s)
- Benedict G Tan
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Christian D Mutti
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Yonghong Shi
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Xie Xie
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Xuefeng Zhu
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Pedro Silva-Pinheiro
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Katja E Menger
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Héctor Díaz-Maldonado
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden
| | - Wei Wei
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Thomas J Nicholls
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Patrick F Chinnery
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Michal Minczuk
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK.
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden.
| | - Claes M Gustafsson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg 405 30, Sweden.
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27
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Misic J, Milenkovic D, Al-Behadili A, Xie X, Jiang M, Jiang S, Filograna R, Koolmeister C, Siira S, Jenninger L, Filipovska A, Clausen A, Caporali L, Valentino M, La Morgia C, Carelli V, Nicholls T, Wredenberg A, Falkenberg M, Larsson NG. Mammalian RNase H1 directs RNA primer formation for mtDNA replication initiation and is also necessary for mtDNA replication completion. Nucleic Acids Res 2022; 50:8749-8766. [PMID: 35947649 PMCID: PMC9410905 DOI: 10.1093/nar/gkac661] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/08/2022] [Accepted: 08/04/2022] [Indexed: 12/24/2022] Open
Abstract
The in vivo role for RNase H1 in mammalian mitochondria has been much debated. Loss of RNase H1 is embryonic lethal and to further study its role in mtDNA expression we characterized a conditional knockout of Rnaseh1 in mouse heart. We report that RNase H1 is essential for processing of RNA primers to allow site-specific initiation of mtDNA replication. Without RNase H1, the RNA:DNA hybrids at the replication origins are not processed and mtDNA replication is initiated at non-canonical sites and becomes impaired. Importantly, RNase H1 is also needed for replication completion and in its absence linear deleted mtDNA molecules extending between the two origins of mtDNA replication are formed accompanied by mtDNA depletion. The steady-state levels of mitochondrial transcripts follow the levels of mtDNA, and RNA processing is not altered in the absence of RNase H1. Finally, we report the first patient with a homozygous pathogenic mutation in the hybrid-binding domain of RNase H1 causing impaired mtDNA replication. In contrast to catalytically inactive variants of RNase H1, this mutant version has enhanced enzyme activity but shows impaired primer formation. This finding shows that the RNase H1 activity must be strictly controlled to allow proper regulation of mtDNA replication.
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Affiliation(s)
- Jelena Misic
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden
| | | | - Ali Al-Behadili
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Xie Xie
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Min Jiang
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China
| | - Shan Jiang
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden
| | - Roberta Filograna
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden
| | - Camilla Koolmeister
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden
| | - Stefan J Siira
- Harry Perkins Institute of Medical Research and ARC Centre of Excellence in Synthetic Biology, Nedlands, WA 6009, Australia
| | - Louise Jenninger
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research and ARC Centre of Excellence in Synthetic Biology, Nedlands, WA 6009, Australia,Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA, Australia
| | - Anders R Clausen
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Leonardo Caporali
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Maria Lucia Valentino
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy,Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Chiara La Morgia
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Valerio Carelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy,Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Thomas J Nicholls
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Anna Wredenberg
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
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28
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Li J, Jiang X, Li C, Che H, Ling L, Wei Z. Proteomic alteration of endometrial tissues during secretion in polycystic ovary syndrome may affect endometrial receptivity. Clin Proteomics 2022; 19:19. [PMID: 35643455 PMCID: PMC9145147 DOI: 10.1186/s12014-022-09353-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 04/18/2022] [Indexed: 11/10/2022] Open
Abstract
AbstractEmbryo implantation is a complex developmental process that requires coordinated interactions among the embryo, endometrium, and the microenvironment of endometrium factors. Even though the impaired endometrial receptivity of patients with polycystic ovary syndrome (PCOS) is known, understanding of endometrial receptivity is limited. A proteomics study in three patients with PCOS and 3 fertile women was performed to understand the impaired endometrial receptivity in patients with PCOS during luteal phases. Through isobaric tags for relative and absolute quantitation (iTRAQ) analyses, we identified 232 unique proteins involved in the metabolism, inflammation, and cell adhesion molecules. Finally, our results suggested that energy metabolism can affect embryo implantation, whereas inflammation and cell adhesion molecules can affect both endometrial conversion and receptivity. Our results showed that endometrial receptive damage in patients with PCOS is not a single factor. It is caused by many proteins, pathways, systems, and abnormalities, which interact with each other and make endometrial receptive research more difficult.
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29
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Organization and expression of the mammalian mitochondrial genome. Nat Rev Genet 2022; 23:606-623. [PMID: 35459860 DOI: 10.1038/s41576-022-00480-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/21/2022] [Indexed: 02/07/2023]
Abstract
The mitochondrial genome encodes core subunits of the respiratory chain that drives oxidative phosphorylation and is, therefore, essential for energy conversion. Advances in high-throughput sequencing technologies and cryoelectron microscopy have shed light on the structure and organization of the mitochondrial genome and revealed unique mechanisms of mitochondrial gene regulation. New animal models of impaired mitochondrial protein synthesis have shown how the coordinated regulation of the cytoplasmic and mitochondrial translation machineries ensures the correct assembly of the respiratory chain complexes. These new technologies and disease models are providing a deeper understanding of mitochondrial genome organization and expression and of the diseases caused by impaired energy conversion, including mitochondrial, neurodegenerative, cardiovascular and metabolic diseases. They also provide avenues for the development of treatments for these conditions.
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30
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Miranda M, Bonekamp NA, Kühl I. Starting the engine of the powerhouse: mitochondrial transcription and beyond. Biol Chem 2022; 403:779-805. [PMID: 35355496 DOI: 10.1515/hsz-2021-0416] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/09/2022] [Indexed: 12/25/2022]
Abstract
Mitochondria are central hubs for cellular metabolism, coordinating a variety of metabolic reactions crucial for human health. Mitochondria provide most of the cellular energy via their oxidative phosphorylation (OXPHOS) system, which requires the coordinated expression of genes encoded by both the nuclear (nDNA) and mitochondrial genomes (mtDNA). Transcription of mtDNA is not only essential for the biogenesis of the OXPHOS system, but also generates RNA primers necessary to initiate mtDNA replication. Like the prokaryotic system, mitochondria have no membrane-based compartmentalization to separate the different steps of mtDNA maintenance and expression and depend entirely on nDNA-encoded factors imported into the organelle. Our understanding of mitochondrial transcription in mammalian cells has largely progressed, but the mechanisms regulating mtDNA gene expression are still poorly understood despite their profound importance for human disease. Here, we review mechanisms of mitochondrial gene expression with a focus on the recent findings in the field of mammalian mtDNA transcription and disease phenotypes caused by defects in proteins involved in this process.
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Affiliation(s)
- Maria Miranda
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne, D-50931, Germany
| | - Nina A Bonekamp
- Department of Neuroanatomy, Mannheim Center for Translational Neurosciences (MCTN), Medical Faculty Mannheim, Heidelberg University, Mannheim, D-68167, Germany
| | - Inge Kühl
- Department of Cell Biology, Institute of Integrative Biology of the Cell (I2BC), UMR9198, CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, F-91190, France
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31
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Singh M, Posse V, Peter B, Falkenberg M, Gustafsson C. Ribonucleotides embedded in template DNA impair mitochondrial RNA polymerase progression. Nucleic Acids Res 2022; 50:989-999. [PMID: 35018464 PMCID: PMC8789056 DOI: 10.1093/nar/gkab1251] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 11/30/2021] [Accepted: 12/07/2021] [Indexed: 11/12/2022] Open
Abstract
Human mitochondria lack ribonucleotide excision repair pathways, causing misincorporated ribonucleotides (rNMPs) to remain embedded in the mitochondrial genome. Previous studies have demonstrated that human mitochondrial DNA polymerase γ can bypass a single rNMP, but that longer stretches of rNMPs present an obstacle to mitochondrial DNA replication. Whether embedded rNMPs also affect mitochondrial transcription has not been addressed. Here we demonstrate that mitochondrial RNA polymerase elongation activity is affected by a single, embedded rNMP in the template strand. The effect is aggravated at stretches with two or more consecutive rNMPs in a row and cannot be overcome by addition of the mitochondrial transcription elongation factor TEFM. Our findings lead us to suggest that impaired transcription may be of functional relevance in genetic disorders associated with imbalanced nucleotide pools and higher levels of embedded rNMPs.
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Affiliation(s)
- Meenakshi Singh
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, SE-405 30, Sweden
| | - Viktor Posse
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, SE-405 30, Sweden
| | - Bradley Peter
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, SE-405 30, Sweden
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, SE-405 30, Sweden
| | - Claes M Gustafsson
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, SE-405 30, Sweden
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32
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Choi WS, Garcia-Diaz M. A minimal motif for sequence recognition by mitochondrial transcription factor A (TFAM). Nucleic Acids Res 2021; 50:322-332. [PMID: 34928349 PMCID: PMC8754647 DOI: 10.1093/nar/gkab1230] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 11/13/2021] [Accepted: 12/10/2021] [Indexed: 11/16/2022] Open
Abstract
Mitochondrial transcription factor A (TFAM) plays a critical role in mitochondrial transcription initiation and mitochondrial DNA (mtDNA) packaging. Both functions require DNA binding, but in one case TFAM must recognize a specific promoter sequence, while packaging requires coating of mtDNA by association with non sequence-specific regions. The mechanisms by which TFAM achieves both sequence-specific and non sequence-specific recognition have not yet been determined. Existing crystal structures of TFAM bound to DNA allowed us to identify two guanine-specific interactions that are established between TFAM and the bound DNA. These interactions are observed when TFAM is bound to both specific promoter sequences and non-sequence specific DNA. These interactions are established with two guanine bases separated by 10 random nucleotides (GN10G). Our biochemical results demonstrate that the GN10G consensus is essential for transcriptional initiation and contributes to facilitating TFAM binding to DNA substrates. Furthermore, we report a crystal structure of TFAM in complex with a non sequence-specific sequence containing a GN10G consensus. The structure reveals a unique arrangement in which TFAM bridges two DNA substrates while maintaining the GN10G interactions. We propose that the GN10G consensus is key to facilitate the interaction of TFAM with DNA.
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Affiliation(s)
- Woo Suk Choi
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - Miguel Garcia-Diaz
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
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Ohkubo A, Van Haute L, Rudler DL, Stentenbach M, Steiner FA, Rackham O, Minczuk M, Filipovska A, Martinou JC. The FASTK family proteins fine-tune mitochondrial RNA processing. PLoS Genet 2021; 17:e1009873. [PMID: 34748562 PMCID: PMC8601606 DOI: 10.1371/journal.pgen.1009873] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 11/18/2021] [Accepted: 10/11/2021] [Indexed: 12/28/2022] Open
Abstract
Transcription of the human mitochondrial genome and correct processing of the two long polycistronic transcripts are crucial for oxidative phosphorylation. According to the tRNA punctuation model, nucleolytic processing of these large precursor transcripts occurs mainly through the excision of the tRNAs that flank most rRNAs and mRNAs. However, some mRNAs are not punctuated by tRNAs, and it remains largely unknown how these non-canonical junctions are resolved. The FASTK family proteins are emerging as key players in non-canonical RNA processing. Here, we have generated human cell lines carrying single or combined knockouts of several FASTK family members to investigate their roles in non-canonical RNA processing. The most striking phenotypes were obtained with loss of FASTKD4 and FASTKD5 and with their combined double knockout. Comprehensive mitochondrial transcriptome analyses of these cell lines revealed a defect in processing at several canonical and non-canonical RNA junctions, accompanied by an increase in specific antisense transcripts. Loss of FASTKD5 led to the most severe phenotype with marked defects in mitochondrial translation of key components of the electron transport chain complexes and in oxidative phosphorylation. We reveal that the FASTK protein family members are crucial regulators of non-canonical junction and non-coding mitochondrial RNA processing. As a legacy of their bacterial origin, mitochondria have retained their own genome with a unique gene expression system. All mitochondrially encoded proteins are essential components of the respiratory chain. Therefore, the mitochondrial gene expression is crucial for their iconic role as the ‘powerhouse of the cell’–ATP synthesis through oxidative phosphorylation. Consistently, defects in enzymes involved in this gene expression system are a common source of incurable inherited metabolic disorders, called mitochondrial diseases. The human mitochondrial transcription generates long polycistronic transcripts that carry information for multiple genes, so that the expression level of each gene is mainly regulated through post-transcriptional events. The polycistronic transcript first undergoes RNA processing, where individual mRNA, rRNA, and tRNA are cleaved off. However, its entire molecular mechanism remains unclear, and in particular, ‘non-canonical’ RNA processing has been poorly understood. To address this question, we studied the FASTK family proteins, emerging key mitochondrial post-transcriptional regulators. We generated different human cell lines carrying single or combined disruption of FASTKD3, FASTKD4, and FASTKD5 genes, and analyzed them using biochemical and genetic approaches. We show that the FASTK family members fine-tune the processing of both ‘canonical’ and ‘non-canonical’ mitochondrial RNA junctions.
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Affiliation(s)
- Akira Ohkubo
- Department of Cell Biology, University of Geneva, Geneva, Switzerland
| | - Lindsey Van Haute
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Danielle L. Rudler
- Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Perth, Australia
- ARC Centre of Excellence in Synthetic Biology, Queen Elizabeth II Medical Centre, Perth, Australia
- Centre for Medical Research, The University of Western Australia, Queen Elizabeth II Medical Centre, Perth, Australia
| | - Maike Stentenbach
- Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Perth, Australia
- ARC Centre of Excellence in Synthetic Biology, Queen Elizabeth II Medical Centre, Perth, Australia
- Centre for Medical Research, The University of Western Australia, Queen Elizabeth II Medical Centre, Perth, Australia
| | - Florian A. Steiner
- Department of Molecular Biology, University of Geneva, Geneva, Switzerland
| | - Oliver Rackham
- Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Perth, Australia
- ARC Centre of Excellence in Synthetic Biology, Queen Elizabeth II Medical Centre, Perth, Australia
- School of Pharmacy and Biomedical Sciences, Curtin University, Perth, Australia
- Curtin Health Innovation Research Institute, Curtin University, Perth, Australia
- Telethon Kids Institute, Perth Children’s Hospital, Perth, Australia
| | - Michal Minczuk
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Perth, Australia
- ARC Centre of Excellence in Synthetic Biology, Queen Elizabeth II Medical Centre, Perth, Australia
- Centre for Medical Research, The University of Western Australia, Queen Elizabeth II Medical Centre, Perth, Australia
- Telethon Kids Institute, Perth Children’s Hospital, Perth, Australia
- School of Molecular Sciences, The University of Western Australia, Perth, Australia
- * E-mail: (AF); (J-CM)
| | - Jean-Claude Martinou
- Department of Cell Biology, University of Geneva, Geneva, Switzerland
- * E-mail: (AF); (J-CM)
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Bhatta A, Dienemann C, Cramer P, Hillen HS. Structural basis of RNA processing by human mitochondrial RNase P. Nat Struct Mol Biol 2021; 28:713-723. [PMID: 34489609 PMCID: PMC8437803 DOI: 10.1038/s41594-021-00637-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 07/01/2021] [Indexed: 02/07/2023]
Abstract
Human mitochondrial transcripts contain messenger and ribosomal RNAs flanked by transfer RNAs (tRNAs), which are excised by mitochondrial RNase (mtRNase) P and Z to liberate all RNA species. In contrast to nuclear or bacterial RNase P, mtRNase P is not a ribozyme but comprises three protein subunits that carry out RNA cleavage and methylation by unknown mechanisms. Here, we present the cryo-EM structure of human mtRNase P bound to precursor tRNA, which reveals a unique mechanism of substrate recognition and processing. Subunits TRMT10C and SDR5C1 form a subcomplex that binds conserved mitochondrial tRNA elements, including the anticodon loop, and positions the tRNA for methylation. The endonuclease PRORP is recruited and activated through interactions with its PPR and nuclease domains to ensure precise pre-tRNA cleavage. The structure provides the molecular basis for the first step of RNA processing in human mitochondria.
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Affiliation(s)
- Arjun Bhatta
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
- Research Group Structure and Function of Molecular Machines, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Christian Dienemann
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany
| | - Hauke S Hillen
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany.
- Research Group Structure and Function of Molecular Machines, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
- Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany.
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Menger KE, Rodríguez-Luis A, Chapman J, Nicholls TJ. Controlling the topology of mammalian mitochondrial DNA. Open Biol 2021; 11:210168. [PMID: 34547213 PMCID: PMC8455175 DOI: 10.1098/rsob.210168] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The genome of mitochondria, called mtDNA, is a small circular DNA molecule present at thousands of copies per human cell. MtDNA is packaged into nucleoprotein complexes called nucleoids, and the density of mtDNA packaging affects mitochondrial gene expression. Genetic processes such as transcription, DNA replication and DNA packaging alter DNA topology, and these topological problems are solved by a family of enzymes called topoisomerases. Within mitochondria, topoisomerases are involved firstly in the regulation of mtDNA supercoiling and secondly in disentangling interlinked mtDNA molecules following mtDNA replication. The loss of mitochondrial topoisomerase activity leads to defects in mitochondrial function, and variants in the dual-localized type IA topoisomerase TOP3A have also been reported to cause human mitochondrial disease. We review the current knowledge on processes that alter mtDNA topology, how mtDNA topology is modulated by the action of topoisomerases, and the consequences of altered mtDNA topology for mitochondrial function and human health.
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Affiliation(s)
- Katja E. Menger
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Alejandro Rodríguez-Luis
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - James Chapman
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Thomas J. Nicholls
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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36
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Renaudin X, Lee M, Shehata M, Surmann EM, Venkitaraman AR. BRCA2 deficiency reveals that oxidative stress impairs RNaseH1 function to cripple mitochondrial DNA maintenance. Cell Rep 2021; 36:109478. [PMID: 34348152 PMCID: PMC8356021 DOI: 10.1016/j.celrep.2021.109478] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 06/16/2021] [Accepted: 07/13/2021] [Indexed: 01/07/2023] Open
Abstract
Oxidative stress is a ubiquitous cellular challenge implicated in aging, neurodegeneration, and cancer. By studying pathogenic mutations in the tumor suppressor BRCA2, we identify a general mechanism by which oxidative stress restricts mitochondrial (mt)DNA replication. BRCA2 inactivation induces R-loop accumulation in the mtDNA regulatory region and diminishes mtDNA replication initiation. In BRCA2-deficient cells, intracellular reactive oxygen species (ROS) are elevated, and ROS scavengers suppress the mtDNA defects. Conversely, wild-type cells exposed to oxidative stress by pharmacologic or genetic manipulation phenocopy these defects. Mechanistically, we find that 8-oxoguanine accumulation in mtDNA caused by oxidative stress suffices to impair recruitment of the mitochondrial enzyme RNaseH1 to sites of R-loop accrual, restricting mtDNA replication initiation. Thus, oxidative stress impairs RNaseH1 function to cripple mtDNA maintenance. Our findings highlight a molecular mechanism that links oxidative stress to mitochondrial dysfunction and is elicited by the inactivation of genes implicated in neurodegeneration and cancer. BRCA2-deficient cells accumulate mtDNA R-loops due to oxidative stress This stress creates 8-oxoguanine lesions impairing RNaseH1 recruitment to mtDNA RNaseH1 impairment triggers R-loop formation and restricts mtDNA replication Other sources of oxidative stress also cripple mtDNA maintenance via this mechanism
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Affiliation(s)
- Xavier Renaudin
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Miyoung Lee
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Mona Shehata
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Eva-Maria Surmann
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Ashok R Venkitaraman
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK.
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37
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Jiang M, Xie X, Zhu X, Jiang S, Milenkovic D, Misic J, Shi Y, Tandukar N, Li X, Atanassov I, Jenninger L, Hoberg E, Albarran-Gutierrez S, Szilagyi Z, Macao B, Siira SJ, Carelli V, Griffith JD, Gustafsson CM, Nicholls TJ, Filipovska A, Larsson NG, Falkenberg M. The mitochondrial single-stranded DNA binding protein is essential for initiation of mtDNA replication. SCIENCE ADVANCES 2021; 7:eabf8631. [PMID: 34215584 PMCID: PMC11057760 DOI: 10.1126/sciadv.abf8631] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 05/20/2021] [Indexed: 06/13/2023]
Abstract
We report a role for the mitochondrial single-stranded DNA binding protein (mtSSB) in regulating mitochondrial DNA (mtDNA) replication initiation in mammalian mitochondria. Transcription from the light-strand promoter (LSP) is required both for gene expression and for generating the RNA primers needed for initiation of mtDNA synthesis. In the absence of mtSSB, transcription from LSP is strongly up-regulated, but no replication primers are formed. Using deep sequencing in a mouse knockout model and biochemical reconstitution experiments with pure proteins, we find that mtSSB is necessary to restrict transcription initiation to optimize RNA primer formation at both origins of mtDNA replication. Last, we show that human pathological versions of mtSSB causing severe mitochondrial disease cannot efficiently support primer formation and initiation of mtDNA replication.
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Affiliation(s)
- Min Jiang
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Xie Xie
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Xuefeng Zhu
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Shan Jiang
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden
| | - Dusanka Milenkovic
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Jelena Misic
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden
| | - Yonghong Shi
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Nirwan Tandukar
- Lineberger Comprehensive Cancer Center, Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27514, USA
| | - Xinping Li
- Proteomics Core Facility, Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Ilian Atanassov
- Proteomics Core Facility, Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Louise Jenninger
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Emily Hoberg
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Sara Albarran-Gutierrez
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Zsolt Szilagyi
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Bertil Macao
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Stefan J Siira
- Harry Perkins Institute of Medical Research and ARC Centre of Excellence in Synthetic Biology, Nedlands, WA 6009, Australia
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA, Australia
| | - Valerio Carelli
- Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Jack D Griffith
- Lineberger Comprehensive Cancer Center, Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27514, USA
| | - Claes M Gustafsson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Thomas J Nicholls
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research and ARC Centre of Excellence in Synthetic Biology, Nedlands, WA 6009, Australia
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, WA, Australia
| | - Nils-Göran Larsson
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden.
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden.
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Jang YH, Ahn SR, Shim JY, Lim KI. Engineering Genetic Systems for Treating Mitochondrial Diseases. Pharmaceutics 2021; 13:810. [PMID: 34071708 PMCID: PMC8227772 DOI: 10.3390/pharmaceutics13060810] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/23/2021] [Accepted: 05/24/2021] [Indexed: 12/13/2022] Open
Abstract
Mitochondria are intracellular energy generators involved in various cellular processes. Therefore, mitochondrial dysfunction often leads to multiple serious diseases, including neurodegenerative and cardiovascular diseases. A better understanding of the underlying mitochondrial dysfunctions of the molecular mechanism will provide important hints on how to mitigate the symptoms of mitochondrial diseases and eventually cure them. In this review, we first summarize the key parts of the genetic processes that control the physiology and functions of mitochondria and discuss how alterations of the processes cause mitochondrial diseases. We then list up the relevant core genetic components involved in these processes and explore the mutations of the components that link to the diseases. Lastly, we discuss recent attempts to apply multiple genetic methods to alleviate and further reverse the adverse effects of the core component mutations on the physiology and functions of mitochondria.
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Affiliation(s)
- Yoon-ha Jang
- Department of Chemical and Biological Engineering, Sookmyung Women’s University, Yongsan-gu, Seoul 04310, Korea; (Y.-h.J.); (J.-y.S.)
| | - Sae Ryun Ahn
- Industry Collaboration Center, Industry-Academic Cooperation Foundation, Sookmyung Women’s University, Yongsan-gu, Seoul 04310, Korea;
| | - Ji-yeon Shim
- Department of Chemical and Biological Engineering, Sookmyung Women’s University, Yongsan-gu, Seoul 04310, Korea; (Y.-h.J.); (J.-y.S.)
| | - Kwang-il Lim
- Department of Chemical and Biological Engineering, Sookmyung Women’s University, Yongsan-gu, Seoul 04310, Korea; (Y.-h.J.); (J.-y.S.)
- Industry Collaboration Center, Industry-Academic Cooperation Foundation, Sookmyung Women’s University, Yongsan-gu, Seoul 04310, Korea;
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Elevated TEFM expression promotes growth and metastasis through activation of ROS/ERK signaling in hepatocellular carcinoma. Cell Death Dis 2021; 12:325. [PMID: 33771980 PMCID: PMC7997956 DOI: 10.1038/s41419-021-03618-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 02/15/2021] [Accepted: 02/22/2021] [Indexed: 12/19/2022]
Abstract
TEFM (transcription elongation factor of mitochondria) has been identified as a novel nuclear-encoded transcription elongation factor in the transcription of mitochondrial genome. Our bioinformatics analysis of TCGA data revealed an aberrant over-expression of TEFM in hepatocellular carcinoma (HCC). We analyzed its biological effects and clinical significance in this malignancy. TEFM expression was analyzed by quantitative real-time PCR, western blot, and immunohistochemistry analysis in HCC tissues and cell lines. The effects of TEFM on HCC cell growth and metastasis were determined by cell proliferation, colony formation, flow cytometric cell cycle and apoptosis, migration, and invasion assays. TEFM expression was significantly increased in HCC tissues mainly caused by down-regulation of miR-194-5p. Its increased expression is correlated with poor prognosis of HCC patients. TEFM promoted HCC growth and metastasis both in vitro and in vivo by promoting G1–S cell transition, epithelial-to-mesenchymal transition (EMT), and suppressing cell apoptosis. Mechanistically, TEFM exerts its tumor growth and metastasis promoting effects at least partly through increasing ROS production and subsequently by activation of ERK signaling. Our study suggests that TEFM functions as a vital oncogene in promoting growth and metastasis in HCC and may contribute to the targeted therapy of HCC.
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40
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Basu U, Bostwick AM, Das K, Dittenhafer-Reed KE, Patel SS. Structure, mechanism, and regulation of mitochondrial DNA transcription initiation. J Biol Chem 2020; 295:18406-18425. [PMID: 33127643 PMCID: PMC7939475 DOI: 10.1074/jbc.rev120.011202] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 10/29/2020] [Indexed: 12/14/2022] Open
Abstract
Mitochondria are specialized compartments that produce requisite ATP to fuel cellular functions and serve as centers of metabolite processing, cellular signaling, and apoptosis. To accomplish these roles, mitochondria rely on the genetic information in their small genome (mitochondrial DNA) and the nucleus. A growing appreciation for mitochondria's role in a myriad of human diseases, including inherited genetic disorders, degenerative diseases, inflammation, and cancer, has fueled the study of biochemical mechanisms that control mitochondrial function. The mitochondrial transcriptional machinery is different from nuclear machinery. The in vitro re-constituted transcriptional complexes of Saccharomyces cerevisiae (yeast) and humans, aided with high-resolution structures and biochemical characterizations, have provided a deeper understanding of the mechanism and regulation of mitochondrial DNA transcription. In this review, we will discuss recent advances in the structure and mechanism of mitochondrial transcription initiation. We will follow up with recent discoveries and formative findings regarding the regulatory events that control mitochondrial DNA transcription, focusing on those involved in cross-talk between the mitochondria and nucleus.
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Affiliation(s)
- Urmimala Basu
- Department of Biochemistry and Molecular Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, USA; Graduate School of Biomedical Sciences, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | | | - Kalyan Das
- Department of Microbiology, Immunology, and Transplantation, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | | | - Smita S Patel
- Department of Biochemistry and Molecular Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, USA.
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41
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Mitochondrial Dysfunction in Parkinson's Disease: Focus on Mitochondrial DNA. Biomedicines 2020; 8:biomedicines8120591. [PMID: 33321831 PMCID: PMC7763033 DOI: 10.3390/biomedicines8120591] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/05/2020] [Accepted: 12/08/2020] [Indexed: 12/14/2022] Open
Abstract
Mitochondria, the energy stations of the cell, are the only extranuclear organelles, containing their own (mitochondrial) DNA (mtDNA) and the protein synthesizing machinery. The location of mtDNA in close proximity to the oxidative phosphorylation system of the inner mitochondrial membrane, the main source of reactive oxygen species (ROS), is an important factor responsible for its much higher mutation rate than nuclear DNA. Being more vulnerable to damage than nuclear DNA, mtDNA accumulates mutations, crucial for the development of mitochondrial dysfunction playing a key role in the pathogenesis of various diseases. Good evidence exists that some mtDNA mutations are associated with increased risk of Parkinson’s disease (PD), the movement disorder resulted from the degenerative loss of dopaminergic neurons of substantia nigra. Although their direct impact on mitochondrial function/dysfunction needs further investigation, results of various studies performed using cells isolated from PD patients or their mitochondria (cybrids) suggest their functional importance. Studies involving mtDNA mutator mice also demonstrated the importance of mtDNA deletions, which could also originate from abnormalities induced by mutations in nuclear encoded proteins needed for mtDNA replication (e.g., polymerase γ). However, proteomic studies revealed only a few mitochondrial proteins encoded by mtDNA which were downregulated in various PD models. This suggests nuclear suppression of the mitochondrial defects, which obviously involve cross-talk between nuclear and mitochondrial genomes for maintenance of mitochondrial functioning.
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Dumas L, Herviou P, Dassi E, Cammas A, Millevoi S. G-Quadruplexes in RNA Biology: Recent Advances and Future Directions. Trends Biochem Sci 2020; 46:270-283. [PMID: 33303320 DOI: 10.1016/j.tibs.2020.11.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/30/2020] [Accepted: 11/02/2020] [Indexed: 12/12/2022]
Abstract
RNA G-quadruplexes (RG4s) are four-stranded structures known to control gene expression mechanisms, from transcription to protein synthesis, and DNA-related processes. Their potential impact on RNA biology allows these structures to shape cellular processes relevant to disease development, making their targeting for therapeutic purposes an attractive option. We review here the current knowledge on RG4s, focusing on the latest breakthroughs supporting the notion of transient structures that fluctuate dynamically in cellulo, their interplay with RNA modifications, their role in cell compartmentalization, and their deregulation impacting the host immune response. We emphasize RG4-binding proteins as determinants of their transient conformation and effectors of their biological functions.
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Affiliation(s)
- Leïla Dumas
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III - Paul Sabatier, 31330 Toulouse, France
| | - Pauline Herviou
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III - Paul Sabatier, 31330 Toulouse, France
| | - Erik Dassi
- Laboratory of RNA Regulatory Networks, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, 38123 Trento, (TN), Italy
| | - Anne Cammas
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III - Paul Sabatier, 31330 Toulouse, France
| | - Stefania Millevoi
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III - Paul Sabatier, 31330 Toulouse, France.
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43
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Fei ZY, Wang WS, Li SF, Zi JJ, Yang L, Liu T, Ao S, Liu QQ, Cui QH, Yu M, Xiong W. High expression of the TEFM gene predicts poor prognosis in hepatocellular carcinoma. J Gastrointest Oncol 2020; 11:1291-1304. [PMID: 33457002 PMCID: PMC7807266 DOI: 10.21037/jgo-20-120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 09/25/2020] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Mitochondrial transcription elongation factor (TEFM) is an essential molecule that regulates the replication-transcription switch of mitochondrial DNA. TEFM modulates both transcription elongation and RNA processing in mitochondria. The purpose of the present study was to determine the association of TEFM with tumor progression and prognosis in hepatocellular carcinoma (HCC) patients. METHODS The different protein expression level of TEFM among HCC cell lines was detected by Western blotting. The gene expression profiling interactive analysis (GEPIA) was used to dynamically analyze the mRNA expression of TEFM gene in different stages of HCC. The protein and mRNA expression levels of TEFM were detected by immunohistochemistry, Western blotting and qRT-PCR. The mRNA-SeqV2 expression of TEFM and clinical information of HCC patients were downloaded from the TCGA database by using R3.6.3 software. Next, the relationships between the expression level of TEFM and clinicopathological characteristics and the prognostic value of TEFM were analyzed. A Cox regression model was used for multivariate analysis of the factors that affected the prognosis of HCC. Finally, the association between the expression levels of TEFM and other mitochondrial regulatory genes and HCC biomarker genes was analyzed by GEPIA. RESULTS TEFM is upregulated in HCC cell lines compared to noncancerous liver cell line. TEFM protein and mRNA expression levels in HCC tissues were significantly upregulated compared with those in noncancerous liver tissues. In addition, the mRNA expression level of TEFM was significantly correlated with sex, serum AFP level, and vascular invasion (P<0.05). Further analysis showed that high expression level of TEFM was unfavorable in terms of the prognosis of patients with HCC. Cox multivariate regression analysis showed that patient age, vascular invasion, and TEFM expression were independent factors affecting the prognosis of HCC patients (P<0.05). The expression level of the TEFM gene was significantly positively correlated with the expression of multiple mitochondrial regulatory genes and biomarker genes of HCC (P<0.01, R>0). CONCLUSIONS Our findings reveal that TEFM may play an important role in the progression of HCC. More importantly, the elevated expression of TEFM may potentially predict poor overall survival (OS) and disease-free survival (DFS) in patients with HCC.
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Affiliation(s)
- Zai-Yi Fei
- School of Life Sciences, Yunnan University, Kunming, China
- Key Laboratory for Biochemistry and Molecular Biology of High Education in Yunnan Province, Yunnan University, Kunming, China
| | - Wei-Si Wang
- College of Basic Medical Sciences, Dali University, Dali, China
- Key Laboratory for Clinical Biochemistry of High Education in Yunnan Province, Dali University, Dali, China
| | - Su-Fen Li
- College of Basic Medical Sciences, Dali University, Dali, China
- Key Laboratory for Clinical Biochemistry of High Education in Yunnan Province, Dali University, Dali, China
| | - Jia-Ji Zi
- College of Basic Medical Sciences, Dali University, Dali, China
| | - Li Yang
- School of Life Sciences, Yunnan University, Kunming, China
- Key Laboratory for Biochemistry and Molecular Biology of High Education in Yunnan Province, Yunnan University, Kunming, China
| | - Ting Liu
- School of Life Sciences, Yunnan University, Kunming, China
- Key Laboratory for Biochemistry and Molecular Biology of High Education in Yunnan Province, Yunnan University, Kunming, China
| | - Song Ao
- School of Life Sciences, Yunnan University, Kunming, China
- Key Laboratory for Biochemistry and Molecular Biology of High Education in Yunnan Province, Yunnan University, Kunming, China
| | - Qian-Qian Liu
- School of Life Sciences, Yunnan University, Kunming, China
- Key Laboratory for Biochemistry and Molecular Biology of High Education in Yunnan Province, Yunnan University, Kunming, China
| | - Qing-Hua Cui
- School of Life Sciences, Yunnan University, Kunming, China
- Key Laboratory for Biochemistry and Molecular Biology of High Education in Yunnan Province, Yunnan University, Kunming, China
| | - Min Yu
- School of Life Sciences, Yunnan University, Kunming, China
- Key Laboratory for Biochemistry and Molecular Biology of High Education in Yunnan Province, Yunnan University, Kunming, China
| | - Wei Xiong
- College of Basic Medical Sciences, Dali University, Dali, China
- Key Laboratory for Clinical Biochemistry of High Education in Yunnan Province, Dali University, Dali, China
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Hillis DA, Yadgary L, Weinstock GM, Pardo-Manuel de Villena F, Pomp D, Fowler AS, Xu S, Chan F, Garland T. Genetic Basis of Aerobically Supported Voluntary Exercise: Results from a Selection Experiment with House Mice. Genetics 2020; 216:781-804. [PMID: 32978270 PMCID: PMC7648575 DOI: 10.1534/genetics.120.303668] [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: 05/08/2020] [Accepted: 09/18/2020] [Indexed: 12/14/2022] Open
Abstract
The biological basis of exercise behavior is increasingly relevant for maintaining healthy lifestyles. Various quantitative genetic studies and selection experiments have conclusively demonstrated substantial heritability for exercise behavior in both humans and laboratory rodents. In the "High Runner" selection experiment, four replicate lines of Mus domesticus were bred for high voluntary wheel running (HR), along with four nonselected control (C) lines. After 61 generations, the genomes of 79 mice (9-10 from each line) were fully sequenced and single nucleotide polymorphisms (SNPs) were identified. We used nested ANOVA with MIVQUE estimation and other approaches to compare allele frequencies between the HR and C lines for both SNPs and haplotypes. Approximately 61 genomic regions, across all somatic chromosomes, showed evidence of differentiation; 12 of these regions were differentiated by all methods of analysis. Gene function was inferred largely using Panther gene ontology terms and KO phenotypes associated with genes of interest. Some of the differentiated genes are known to be associated with behavior/motivational systems and/or athletic ability, including Sorl1, Dach1, and Cdh10 Sorl1 is a sorting protein associated with cholinergic neuron morphology, vascular wound healing, and metabolism. Dach1 is associated with limb bud development and neural differentiation. Cdh10 is a calcium ion binding protein associated with phrenic neurons. Overall, these results indicate that selective breeding for high voluntary exercise has resulted in changes in allele frequencies for multiple genes associated with both motivation and ability for endurance exercise, providing candidate genes that may explain phenotypic changes observed in previous studies.
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Affiliation(s)
- David A Hillis
- Genetics, Genomics, and Bioinformatics Graduate Program, University of California, Riverside, California 92521
| | - Liran Yadgary
- Department of Genetics, University of North Carolina at Chapel Hill, North Carolina 27599
| | - George M Weinstock
- The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut 06032
| | | | - Daniel Pomp
- Department of Genetics, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Alexandra S Fowler
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, California 92521
| | - Shizhong Xu
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521
| | - Frank Chan
- Friedrich Miescher Laboratory of the Max Planck Society, 72076 Tübingen, Germany
| | - Theodore Garland
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, California 92521
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45
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Falkenberg M, Gustafsson CM. Mammalian mitochondrial DNA replication and mechanisms of deletion formation. Crit Rev Biochem Mol Biol 2020; 55:509-524. [DOI: 10.1080/10409238.2020.1818684] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Claes M. Gustafsson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
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46
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Bosch JA, Chen CL, Perrimon N. Proximity-dependent labeling methods for proteomic profiling in living cells: An update. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2020; 10:e392. [PMID: 32909689 DOI: 10.1002/wdev.392] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/11/2020] [Accepted: 07/01/2020] [Indexed: 12/14/2022]
Abstract
Characterizing the proteome composition of organelles and subcellular regions of living cells can facilitate the understanding of cellular organization as well as protein interactome networks. Proximity labeling-based methods coupled with mass spectrometry (MS) offer a high-throughput approach for systematic analysis of spatially restricted proteomes. Proximity labeling utilizes enzymes that generate reactive radicals to covalently tag neighboring proteins. The tagged endogenous proteins can then be isolated for further analysis by MS. To analyze protein-protein interactions or identify components that localize to discrete subcellular compartments, spatial expression is achieved by fusing the enzyme to specific proteins or signal peptides that target to particular subcellular regions. Although these technologies have only been introduced recently, they have already provided deep insights into a wide range of biological processes. Here, we provide an updated description and comparison of proximity labeling methods, as well as their applications and improvements. As each method has its own unique features, the goal of this review is to describe how different proximity labeling methods can be used to answer different biological questions. This article is categorized under: Technologies > Analysis of Proteins.
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Affiliation(s)
- Justin A Bosch
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Chiao-Lin Chen
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA.,Howard Hughes Medical Institute, Boston, Massachusetts, USA
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47
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Kotrys AV, Szczesny RJ. Mitochondrial Gene Expression and Beyond-Novel Aspects of Cellular Physiology. Cells 2019; 9:cells9010017. [PMID: 31861673 PMCID: PMC7017415 DOI: 10.3390/cells9010017] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/15/2019] [Accepted: 12/17/2019] [Indexed: 02/06/2023] Open
Abstract
Mitochondria are peculiar organelles whose proper function depends on the crosstalk between two genomes, mitochondrial and nuclear. The human mitochondrial genome (mtDNA) encodes only 13 proteins; nevertheless, its proper expression is essential for cellular homeostasis, as mtDNA-encoded proteins are constituents of mitochondrial respiratory complexes. In addition, mtDNA expression results in the production of RNA molecules, which influence cell physiology once released from the mitochondria into the cytoplasm. As a result, dysfunctions of mtDNA expression may lead to pathologies in humans. Here, we review the mechanisms of mitochondrial gene expression with a focus on recent findings in the field. We summarize the complex turnover of mitochondrial transcripts and present an increasing body of evidence indicating new functions of mitochondrial transcripts. We discuss mitochondrial gene regulation in different cellular contexts, focusing on stress conditions. Finally, we highlight the importance of emerging aspects of mitochondrial gene regulation in human health and disease.
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48
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Nicholls TJ, Spåhr H, Jiang S, Siira SJ, Koolmeister C, Sharma S, Kauppila JHK, Jiang M, Kaever V, Rackham O, Chabes A, Falkenberg M, Filipovska A, Larsson NG, Gustafsson CM. Dinucleotide Degradation by REXO2 Maintains Promoter Specificity in Mammalian Mitochondria. Mol Cell 2019; 76:784-796.e6. [PMID: 31588022 PMCID: PMC6900737 DOI: 10.1016/j.molcel.2019.09.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/12/2019] [Accepted: 09/04/2019] [Indexed: 12/12/2022]
Abstract
Oligoribonucleases are conserved enzymes that degrade short RNA molecules of up to 5 nt in length and are assumed to constitute the final stage of RNA turnover. Here we demonstrate that REXO2 is a specialized dinucleotide-degrading enzyme that shows no preference between RNA and DNA dinucleotide substrates. A heart- and skeletal-muscle-specific knockout mouse displays elevated dinucleotide levels and alterations in gene expression patterns indicative of aberrant dinucleotide-primed transcription initiation. We find that dinucleotides act as potent stimulators of mitochondrial transcription initiation in vitro. Our data demonstrate that increased levels of dinucleotides can be used to initiate transcription, leading to an increase in transcription levels from both mitochondrial promoters and other, nonspecific sequence elements in mitochondrial DNA. Efficient RNA turnover by REXO2 is thus required to maintain promoter specificity and proper regulation of transcription in mammalian mitochondria.
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Affiliation(s)
- Thomas J Nicholls
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Henrik Spåhr
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden; Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm 17177, Sweden
| | - Shan Jiang
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden; Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm 17177, Sweden
| | - Stefan J Siira
- Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; Centre for Medical Research, The University of Western Australia, Nedlands, WA 6009, Australia
| | - Camilla Koolmeister
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden; Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm 17177, Sweden
| | - Sushma Sharma
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå 901 87, Sweden
| | - Johanna H K Kauppila
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Min Jiang
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | - Volkhard Kaever
- Research Core Unit Metabolomics, Hannover Medical School, 30625 Hannover, Germany
| | - Oliver Rackham
- Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; School of Pharmacy and Biomedical Sciences, Curtin University, Bentley, WA 6102, Australia; Curtin Health Innovation Research Institute, Curtin University, Bentley, WA 6102, Australia
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå 901 87, Sweden
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; School of Molecular Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Nils-Göran Larsson
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden; Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm 17177, Sweden.
| | - Claes M Gustafsson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, PO Box 440, Gothenburg 405 30, Sweden.
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49
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Bouda E, Stapon A, Garcia-Diaz M. Mechanisms of mammalian mitochondrial transcription. Protein Sci 2019; 28:1594-1605. [PMID: 31309618 DOI: 10.1002/pro.3688] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 07/10/2019] [Accepted: 07/11/2019] [Indexed: 01/06/2023]
Abstract
Numerous age-related human diseases have been associated with deficiencies in cellular energy production. Moreover, genetic alterations resulting in mitochondrial dysfunction are the cause of inheritable disorders commonly known as mitochondrial diseases. Many of these deficiencies have been directly or indirectly linked to deficits in mitochondrial gene expression. Transcription is an essential step in gene expression and elucidating the molecular mechanisms involved in this process is critical for understanding defects in energy production. For the past five decades, substantial efforts have been invested in the field of mitochondrial transcription. These efforts have led to the discovery of the main protein factors responsible for transcription as well as to a basic mechanistic understanding of the transcription process. They have also revealed various mechanisms of transcriptional regulation as well as the links that exist between the transcription process and downstream processes of RNA maturation. Here, we review the knowledge gathered in early mitochondrial transcription studies and focus on recent findings that shape our current understanding of mitochondrial transcription, posttranscriptional processing, as well as transcriptional regulation in mammalian systems.
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Affiliation(s)
- Emilie Bouda
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York
| | - Anthony Stapon
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York
| | - Miguel Garcia-Diaz
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York
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50
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Organization of DNA in Mammalian Mitochondria. Int J Mol Sci 2019; 20:ijms20112770. [PMID: 31195723 PMCID: PMC6600607 DOI: 10.3390/ijms20112770] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 05/29/2019] [Accepted: 06/03/2019] [Indexed: 12/22/2022] Open
Abstract
As with all organisms that must organize and condense their DNA to fit within the limited volume of a cell or a nucleus, mammalian mitochondrial DNA (mtDNA) is packaged into nucleoprotein structures called nucleoids. In this study, we first introduce the general modes of DNA compaction, especially the role of the nucleoid-associated proteins (NAPs) that structure the bacterial chromosome. We then present the mitochondrial nucleoid and the main factors responsible for packaging of mtDNA: ARS- (autonomously replicating sequence-) binding factor 2 protein (Abf2p) in yeast and mitochondrial transcription factor A (TFAM) in mammals. We summarize the single-molecule manipulation experiments on mtDNA compaction and visualization of mitochondrial nucleoids that have led to our current knowledge on mtDNA compaction. Lastly, we discuss the possible regulatory role of DNA packaging by TFAM in DNA transactions such as mtDNA replication and transcription.
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