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Rolling-Circle Replication in Mitochondrial DNA Inheritance: Scientific Evidence and Significance from Yeast to Human Cells. Genes (Basel) 2020; 11:genes11050514. [PMID: 32384722 PMCID: PMC7288456 DOI: 10.3390/genes11050514] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 04/29/2020] [Accepted: 04/29/2020] [Indexed: 12/23/2022] Open
Abstract
Studies of mitochondrial (mt)DNA replication, which forms the basis of mitochondrial inheritance, have demonstrated that a rolling-circle replication mode exists in yeasts and human cells. In yeast, rolling-circle mtDNA replication mediated by homologous recombination is the predominant pathway for replication of wild-type mtDNA. In human cells, reactive oxygen species (ROS) induce rolling-circle replication to produce concatemers, linear tandem multimers linked by head-to-tail unit-sized mtDNA that promote restoration of homoplasmy from heteroplasmy. The event occurs ahead of mtDNA replication mechanisms observed in mammalian cells, especially under higher ROS load, as newly synthesized mtDNA is concatemeric in hydrogen peroxide-treated human cells. Rolling-circle replication holds promise for treatment of mtDNA heteroplasmy-attributed diseases, which are regarded as incurable. This review highlights the potential therapeutic value of rolling-circle mtDNA replication.
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Chen XJ, Clark-Walker GD. Unveiling the mystery of mitochondrial DNA replication in yeasts. Mitochondrion 2017; 38:17-22. [PMID: 28778567 DOI: 10.1016/j.mito.2017.07.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 07/12/2017] [Accepted: 07/28/2017] [Indexed: 11/27/2022]
Abstract
Conventional DNA replication is initiated from specific origins and requires the synthesis of RNA primers for both the leading and lagging strands. In contrast, the replication of yeast mitochondrial DNA is origin-independent. The replication of the leading strand is likely primed by recombinational structures and proceeded by a rolling circle mechanism. The coexistent linear and circular DNA conformers facilitate the recombination-based initiation. The replication of the lagging strand is poorly understood. Re-evaluation of published data suggests that the rolling circle may also provide structures for the synthesis of the lagging-strand by mechanisms such as template switching. Thus, the coupling of recombination with rolling circle replication and possibly, template switching, may have been selected as an economic replication mode to accommodate the reductive evolution of mitochondria. Such a replication mode spares the need for conventional replicative components, including those required for origin recognition/remodelling, RNA primer synthesis and lagging-strand processing.
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Affiliation(s)
- Xin Jie Chen
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA.
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Rendeková J, Ward TA, Šimoničová L, Thomas PH, Nosek J, Tomáška Ľ, McHugh PJ, Chovanec M. Mgm101: A double-duty Rad52-like protein. Cell Cycle 2016; 15:3169-3176. [PMID: 27636878 PMCID: PMC5176325 DOI: 10.1080/15384101.2016.1231288] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mgm101 has well-characterized activity for the repair and replication of the mitochondrial genome. Recent work has demonstrated a further role for Mgm101 in nuclear DNA metabolism, contributing to an S-phase specific DNA interstrand cross-link repair pathway that acts redundantly with a pathway controlled by Pso2 exonuclease. Due to involvement of FANCM, FANCJ and FANCP homologues (Mph1, Chl1 and Slx4), this pathway has been described as a Fanconi anemia-like pathway. In this pathway, Mgm101 physically interacts with the DNA helicase Mph1 and the MutSα (Msh2/Msh6) heterodimer, but its precise role is yet to be elucidated. Data presented here suggests that Mgm101 functionally overlaps with Rad52, supporting previous suggestions that, based on protein structure and biochemical properties, Mgm101 and Rad52 belong to a family of proteins with similar function. In addition, our data shows that this overlap extends to the function of both proteins at telomeres, where Mgm101 is required for telomere elongation during chromosome replication in rad52 defective cells. We hypothesize that Mgm101 could, in Rad52-like manner, preferentially bind single-stranded DNAs (such as at stalled replication forks, broken chromosomes and natural chromosome ends), stabilize them and mediate single-strand annealing-like homologous recombination event to prevent them from converting into toxic structures.
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Affiliation(s)
- Jana Rendeková
- a Department of Genetics , Cancer Research Institute, Biomedical Research Center, Slovak Academy of Science , Bratislava , Slovak Republic
| | - Thomas A Ward
- b Department of Oncology , Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital , Oxford , UK
| | - Lucia Šimoničová
- c Department of Genetics , Faculty of Natural Sciences, Comenius University , Bratislava , Slovakia
| | - Peter H Thomas
- b Department of Oncology , Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital , Oxford , UK
| | - Jozef Nosek
- d Department of Biochemistry , Faculty of Natural Sciences, Comenius University , Bratislava , Slovakia
| | - Ľubomír Tomáška
- c Department of Genetics , Faculty of Natural Sciences, Comenius University , Bratislava , Slovakia
| | - Peter J McHugh
- b Department of Oncology , Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital , Oxford , UK
| | - Miroslav Chovanec
- a Department of Genetics , Cancer Research Institute, Biomedical Research Center, Slovak Academy of Science , Bratislava , Slovak Republic
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Pevala V, Truban D, Bauer JA, Košťan J, Kunová N, Bellová J, Brandstetter M, Marini V, Krejčí L, Tomáška Ľ, Nosek J, Kutejová E. The structure and DNA-binding properties of Mgm101 from a yeast with a linear mitochondrial genome. Nucleic Acids Res 2016; 44:2227-39. [PMID: 26743001 PMCID: PMC4797282 DOI: 10.1093/nar/gkv1529] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 12/22/2015] [Indexed: 11/14/2022] Open
Abstract
To study the mechanisms involved in the maintenance of a linear mitochondrial genome we investigated the biochemical properties of the recombination protein Mgm101 from Candida parapsilosis. We show that CpMgm101 complements defects associated with the Saccharomyces cerevisiae mgm101-1(ts) mutation and that it is present in both the nucleus and mitochondrial nucleoids of C. parapsilosis. Unlike its S. cerevisiae counterpart, CpMgm101 is associated with the entire nucleoid population and is able to bind to a broad range of DNA substrates in a non-sequence specific manner. CpMgm101 is also able to catalyze strand annealing and D-loop formation. CpMgm101 forms a roughly C-shaped trimer in solution according to SAXS. Electron microscopy of a complex of CpMgm101 with a model mitochondrial telomere revealed homogeneous, ring-shaped structures at the telomeric single-stranded overhangs. The DNA-binding properties of CpMgm101, together with its DNA recombination properties, suggest that it can play a number of possible roles in the replication of the mitochondrial genome and the maintenance of its telomeres.
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Affiliation(s)
- Vladimír Pevala
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Dominika Truban
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Mlynská dolina CH-1, Ilkovičova 6, 842 15 Bratislava, Slovakia
| | - Jacob A Bauer
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Július Košťan
- Department for Structural and Computational Biology, Max F. Perutz Laboratories, Dr. Bohr-Gasse 9 (VBC 5), 1030 Vienna, Austria
| | - Nina Kunová
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Jana Bellová
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Marlene Brandstetter
- Electron Microscopy Facility of the Campus Science Support Facilities GmbH, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Victoria Marini
- Department of Biology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic National Centre for Biomolecular Research, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Lumír Krejčí
- Department of Biology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic National Centre for Biomolecular Research, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Ľubomír Tomáška
- Department of Genetics, Faculty of Natural Sciences, Comenius University, Mlynská dolina B-1, Ilkovičova 6, 842 15 Bratislava, Slovakia
| | - Jozef Nosek
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Mlynská dolina CH-1, Ilkovičova 6, 842 15 Bratislava, Slovakia
| | - Eva Kutejová
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia Institute of Microbiology of the CAS, v. v. i., 142 20 Prague, Czech Republic
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Mechanism of homologous recombination and implications for aging-related deletions in mitochondrial DNA. Microbiol Mol Biol Rev 2014; 77:476-96. [PMID: 24006472 DOI: 10.1128/mmbr.00007-13] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Homologous recombination is a universal process, conserved from bacteriophage to human, which is important for the repair of double-strand DNA breaks. Recombination in mitochondrial DNA (mtDNA) was documented more than 4 decades ago, but the underlying molecular mechanism has remained elusive. Recent studies have revealed the presence of a Rad52-type recombination system of bacteriophage origin in mitochondria, which operates by a single-strand annealing mechanism independent of the canonical RecA/Rad51-type recombinases. Increasing evidence supports the notion that, like in bacteriophages, mtDNA inheritance is a coordinated interplay between recombination, repair, and replication. These findings could have profound implications for understanding the mechanism of mtDNA inheritance and the generation of mtDNA deletions in aging cells.
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Matsubara K, Malay AD, Curtis FA, Sharples GJ, Heddle JG. Structural and functional characterization of the Redβ recombinase from bacteriophage λ. PLoS One 2013; 8:e78869. [PMID: 24244379 PMCID: PMC3823998 DOI: 10.1371/journal.pone.0078869] [Citation(s) in RCA: 16] [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: 08/01/2013] [Accepted: 09/23/2013] [Indexed: 11/18/2022] Open
Abstract
The Red system of bacteriophage λ is responsible for the genetic rearrangements that contribute to its rapid evolution and has been successfully harnessed as a research tool for genome manipulation. The key recombination component is Redβ, a ring-shaped protein that facilitates annealing of complementary DNA strands. Redβ shares functional similarities with the human Rad52 single-stranded DNA (ssDNA) annealing protein although their evolutionary relatedness is not well established. Alignment of Rad52 and Redβ sequences shows an overall low level of homology, with 15% identity in the N-terminal core domains as well as important similarities with the Rad52 homolog Sak from phage ul36. Key conserved residues were chosen for mutagenesis and their impact on oligomer formation, ssDNA binding and annealing was probed. Two conserved regions were identified as sites important for binding ssDNA; a surface basic cluster and an intersubunit hydrophobic patch, consistent with findings for Rad52. Surprisingly, mutation of Redβ residues in the basic cluster that in Rad52 are involved in ssDNA binding disrupted both oligomer formation and ssDNA binding. Mutations in the equivalent of the intersubunit hydrophobic patch in Rad52 did not affect Redβ oligomerization but did impair DNA binding and annealing. We also identified a single amino acid substitution which had little effect on oligomerization and DNA binding but which inhibited DNA annealing, indicating that these two functions of Redβ can be separated. Taken together, the results provide fresh insights into the structural basis for Redβ function and the important role of quaternary structure.
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Affiliation(s)
| | - Ali D. Malay
- Heddle Initiative Research Unit, RIKEN, Wako, Saitama, Japan
| | - Fiona A. Curtis
- School of Biological and Biomedical Sciences, Department of Chemistry, Durham University, Durham, United Kingdom
| | - Gary J. Sharples
- School of Biological and Biomedical Sciences, Department of Chemistry, Durham University, Durham, United Kingdom
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Wang X, Mbantenkhu M, Wierzbicki S, Chen XJ. Preparation of the Mgm101 recombination protein by MBP-based tagging strategy. J Vis Exp 2013. [PMID: 23851592 DOI: 10.3791/50448] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The MGM101 gene was identified 20 years ago for its role in the maintenance of mitochondrial DNA. Studies from several groups have suggested that the Mgm101 protein is involved in the recombinational repair of mitochondrial DNA. Recent investigations have indicated that Mgm101 is related to the Rad52-type recombination protein family. These proteins form large oligomeric rings and promote the annealing of homologous single stranded DNA molecules. However, the characterization of Mgm101 has been hindered by the difficulty in producing the recombinant protein. Here, a reliable procedure for the preparation of recombinant Mgm101 is described. Maltose Binding Protein (MBP)-tagged Mgm101 is first expressed in Escherichia coli. The fusion protein is initially purified by amylose affinity chromatography. After being released by proteolytic cleavage, Mgm101 is separated from MBP by cationic exchange chromatography. Monodispersed Mgm101 is then obtained by size exclusion chromatography. A yield of ~0.87 mg of Mgm101 per liter of bacterial culture can be routinely obtained. The recombinant Mgm101 has minimal contamination of DNA. The prepared samples are successfully used for biochemical, structural and single particle image analyses of Mgm101. This protocol may also be used for the preparation of other large oligomeric DNA-binding proteins that may be misfolded and toxic to bacterial cells.
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Affiliation(s)
- Xiaowen Wang
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, NY, USA
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Mbantenkhu M, Wierzbicki S, Wang X, Guo S, Wilkens S, Chen XJ. A short carboxyl-terminal tail is required for single-stranded DNA binding, higher-order structural organization, and stability of the mitochondrial single-stranded annealing protein Mgm101. Mol Biol Cell 2013; 24:1507-18. [PMID: 23536705 PMCID: PMC3655812 DOI: 10.1091/mbc.e13-01-0006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Mgm101 is a Rad52-type single-stranded annealing protein (SSAP) required for mitochondrial DNA (mtDNA) repair and maintenance. Structurally, Mgm101 forms large oligomeric rings. Here we determine the function(s) of a 32-amino acid carboxyl-terminal tail (Mgm101(238-269)) conserved in the Mgm101 family of proteins. Mutagenic analysis shows that Lys-253, Trp-257, Arg-259, and Tyr-268 are essential for mtDNA maintenance. Mutations in Lys-251, Arg-252, Lys-260, and Tyr-266 affect mtDNA stability at 37°C and under oxidative stress. The Y268A mutation severely affects single-stranded DNA (ssDNA) binding without altering the ring structure. Mutations in the Lys-251-Arg-252-Lys-253 positive triad also affect ssDNA binding. Moreover, the C-tail alone is sufficient to mediate ssDNA binding. Finally, we find that the W257A and R259A mutations dramatically affect the conformation and oligomeric state of Mgm101. These structural alterations correlate with protein degradation in vivo. The data thus indicate that the C-tail of Mgm101, likely displayed on the ring surface, is required for ssDNA binding, higher-order structural organization, and protein stability. We speculate that an initial electrostatic and base-stacking interaction with ssDNA could remodel ring organization. This may facilitate the formation of nucleoprotein filaments competent for mtDNA repair. These findings could have broad implications for understanding how SSAPs promote DNA repair and genome maintenance.
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Affiliation(s)
- MacMillan Mbantenkhu
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
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The N-terminal intrinsically disordered domain of Mgm101p is localized to the mitochondrial nucleoid. PLoS One 2013; 8:e56465. [PMID: 23418572 PMCID: PMC3572067 DOI: 10.1371/journal.pone.0056465] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Accepted: 01/14/2013] [Indexed: 01/22/2023] Open
Abstract
The mitochondrial genome maintenance gene, MGM101, is essential for yeasts that depend on mitochondrial DNA replication. Previously, in Saccharomyces cerevisiae, it has been found that the carboxy-terminal two-thirds of Mgm101p has a functional core. Furthermore, there is a high level of amino acid sequence conservation in this region from widely diverse species. By contrast, the amino-terminal region, that is also essential for function, does not have recognizable conservation. Using a bioinformatic approach we find that the functional core from yeast and a corresponding region of Mgm101p from the coral Acropora millepora have an ordered structure, while the N-terminal domains of sequences from yeast and coral are predicted to be disordered. To examine whether ordered and disordered domains of Mgm101p have specific or general functions we made chimeric proteins from yeast and coral by swapping the two regions. We find, by an in vivo assay in S.cerevisiae, that the ordered domain of A.millepora can functionally replace the yeast core region but the disordered domain of the coral protein cannot substitute for its yeast counterpart. Mgm101p is found in the mitochondrial nucleoid along with enzymes and proteins involved in mtDNA replication. By attaching green fluorescent protein to the N-terminal disordered domain of yeast Mgm101p we find that GFP is still directed to the mitochondrial nucleoid where full-length Mgm101p-GFP is targeted.
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