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Brischigliaro M, Sierra-Magro A, Ahn A, Barrientos A. Mitochondrial ribosome biogenesis and redox sensing. FEBS Open Bio 2024. [PMID: 38849194 DOI: 10.1002/2211-5463.13844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/06/2024] [Accepted: 05/29/2024] [Indexed: 06/09/2024] Open
Abstract
Mitoribosome biogenesis is a complex process involving RNA elements encoded in the mitochondrial genome and mitoribosomal proteins typically encoded in the nuclear genome. This process is orchestrated by extra-ribosomal proteins, nucleus-encoded assembly factors, which play roles across all assembly stages to coordinate ribosomal RNA processing and maturation with the sequential association of ribosomal proteins. Both biochemical studies and recent cryo-EM structures of mammalian mitoribosomes have provided insights into their assembly process. In this article, we will briefly outline the current understanding of mammalian mitoribosome biogenesis pathways and the factors involved. Special attention is devoted to the recent identification of iron-sulfur clusters as structural components of the mitoribosome and a small subunit assembly factor, the existence of redox-sensitive cysteines in mitoribosome proteins and assembly factors, and the role they may play as redox sensor units to regulate mitochondrial translation under stress.
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Affiliation(s)
| | - Ana Sierra-Magro
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA
| | - Ahram Ahn
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, FL, USA
| | - Antoni Barrientos
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, FL, USA
- Bruce W. Carter Department of Veterans Affairs VA Medical Center, Miami, FL, USA
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2
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Vučković A, Freyer C, Wredenberg A, Hillen HS. The molecular machinery for maturation of primary mtDNA transcripts. Hum Mol Genet 2024; 33:R19-R25. [PMID: 38779769 PMCID: PMC11112384 DOI: 10.1093/hmg/ddae023] [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: 01/31/2024] [Revised: 01/31/2024] [Accepted: 02/08/2024] [Indexed: 05/25/2024] Open
Abstract
Human mitochondria harbour a circular, polyploid genome (mtDNA) encoding 11 messenger RNAs (mRNAs), two ribosomal RNAs (rRNAs) and 22 transfer RNAs (tRNAs). Mitochondrial transcription produces long, polycistronic transcripts that span almost the entire length of the genome, and hence contain all three types of RNAs. The primary transcripts then undergo a number of processing and maturation steps, which constitute key regulatory points of mitochondrial gene expression. The first step of mitochondrial RNA processing consists of the separation of primary transcripts into individual, functional RNA molecules and can occur by two distinct pathways. Both are carried out by dedicated molecular machineries that substantially differ from RNA processing enzymes found elsewhere. As a result, the underlying molecular mechanisms remain poorly understood. Over the last years, genetic, biochemical and structural studies have identified key players involved in both RNA processing pathways and provided the first insights into the underlying mechanisms. Here, we review our current understanding of RNA processing in mammalian mitochondria and provide an outlook on open questions in the field.
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MESH Headings
- Humans
- DNA, Mitochondrial/genetics
- RNA Processing, Post-Transcriptional
- Mitochondria/genetics
- Mitochondria/metabolism
- RNA, Mitochondrial/genetics
- RNA, Mitochondrial/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Animals
- Transcription, Genetic
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
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Affiliation(s)
- Ana Vučković
- Department of Cellular Biochemistry, University Medical Center Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
- Research Group Structure and Function of Molecular Machines, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Christoph Freyer
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Anna Steckséns gata 47, 171 64 Solna, Sweden
| | - Anna Wredenberg
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Anna Steckséns gata 47, 171 64 Solna, Sweden
| | - Hauke S Hillen
- Department of Cellular Biochemistry, University Medical Center Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
- Research Group Structure and Function of Molecular Machines, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Robert-Koch-Straße 40, 37073 Göttingen, Germany
- Research Group Structure and Function of Molecular Machines, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Justus-von-Liebig-Weg 11, Goettingen 37077, Germany
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3
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Sarıgül İ, Žukova A, Alparslan E, Remm S, Pihlak M, Kaldalu N, Tenson T, Maiväli Ü. Involvement of Escherichia coli YbeX/CorC in ribosomal metabolism. Mol Microbiol 2024; 121:984-1001. [PMID: 38494741 DOI: 10.1111/mmi.15248] [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: 10/27/2023] [Revised: 02/15/2024] [Accepted: 02/20/2024] [Indexed: 03/19/2024]
Abstract
YbeX of Escherichia coli, a member of the CorC protein family, is encoded in the same operon with ribosome-associated proteins YbeY and YbeZ. Here, we report the involvement of YbeX in ribosomal metabolism. The ΔybeX cells accumulate distinct 16S rRNA degradation intermediates in the 30S particles and the 70S ribosomes. E. coli lacking ybeX has a lengthened lag phase upon outgrowth from the stationary phase. This growth phenotype is heterogeneous at the individual cell level and especially prominent under low extracellular magnesium levels. The ΔybeX strain is sensitive to elevated growth temperatures and to several ribosome-targeting antibiotics that have in common the ability to induce the cold shock response in E. coli. Although generally milder, the phenotypes of the ΔybeX mutant overlap with those caused by ybeY deletion. A genetic screen revealed partial compensation of the ΔybeX growth phenotype by the overexpression of YbeY. These findings indicate an interconnectedness among the ybeZYX operon genes, highlighting their roles in ribosomal assembly and/or degradation.
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Affiliation(s)
- İsmail Sarıgül
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Amata Žukova
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Emel Alparslan
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Sille Remm
- Institute of Technology, University of Tartu, Tartu, Estonia
- Institute of Medical Microbiology, University of Zurich, Zürich, Switzerland
| | - Margus Pihlak
- Department of Cybernetics, Tallinn University of Technology, Tallinn, Estonia
| | - Niilo Kaldalu
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Tanel Tenson
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Ülo Maiväli
- Institute of Technology, University of Tartu, Tartu, Estonia
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4
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Nikitchina N, Ulashchik E, Shmanai V, Heckel AM, Tarassov I, Mazunin I, Entelis N. Targeting of CRISPR-Cas12a crRNAs into human mitochondria. Biochimie 2024; 217:74-85. [PMID: 37690471 DOI: 10.1016/j.biochi.2023.09.006] [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: 05/15/2023] [Revised: 08/10/2023] [Accepted: 09/04/2023] [Indexed: 09/12/2023]
Abstract
Mitochondrial gene editing holds great promise as a therapeutic approach for mitochondrial diseases caused by mutations in the mitochondrial DNA (mtDNA). Current strategies focus on reducing mutant mtDNA heteroplasmy levels through targeted cleavage or base editing. However, the delivery of editing components into mitochondria remains a challenge. Here we investigate the import of CRISPR-Cas12a system guide RNAs (crRNAs) into human mitochondria and study the structural requirements for this process by northern blot analysis of RNA isolated from nucleases-treated mitoplasts. To investigate whether the fusion of crRNA with known RNA import determinants (MLS) improve its mitochondrial targeting, we added MLS hairpin structures at 3'-end of crRNA and demonstrated that this did not impact crRNA ability to program specific cleavage of DNA in lysate of human cells expressing AsCas12a nuclease. Surprisingly, mitochondrial localization of the fused crRNA molecules was not improved compared to non-modified version, indicating that structured scaffold domain of crRNA can probably function as MLS, assuring crRNA mitochondrial import. Then, we designed a series of crRNAs targeting different regions of mtDNA and demonstrated their ability to program specific cleavage of mtDNA fragments in cell lysate and their partial localization in mitochondrial matrix in human cells transfected with these RNA molecules. We hypothesize that mitochondrial import of crRNAs may depend on their secondary structure/sequence. We presume that imported crRNA allow reconstituting the active crRNA/Cas12a system in human mitochondria, which can contribute to the development of effective strategies for mitochondrial gene editing and potential future treatment of mitochondrial diseases.
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Affiliation(s)
- Natalia Nikitchina
- UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, Strasbourg, 67000, France
| | - Egor Ulashchik
- Institute of Physical Organic Chemistry, National Academy of Science of Belarus, Minsk, 220072, Belarus
| | - Vadim Shmanai
- Institute of Physical Organic Chemistry, National Academy of Science of Belarus, Minsk, 220072, Belarus
| | - Anne-Marie Heckel
- UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, Strasbourg, 67000, France
| | - Ivan Tarassov
- UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, Strasbourg, 67000, France
| | - Ilya Mazunin
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow, 143026, Russia
| | - Nina Entelis
- UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, Strasbourg, 67000, France.
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5
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Gruffaz C, Smirnov A. GTPase Era at the heart of ribosome assembly. Front Mol Biosci 2023; 10:1263433. [PMID: 37860580 PMCID: PMC10582724 DOI: 10.3389/fmolb.2023.1263433] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 09/21/2023] [Indexed: 10/21/2023] Open
Abstract
Ribosome biogenesis is a key process in all organisms. It relies on coordinated work of multiple proteins and RNAs, including an array of assembly factors. Among them, the GTPase Era stands out as an especially deeply conserved protein, critically required for the assembly of bacterial-type ribosomes from Escherichia coli to humans. In this review, we bring together and critically analyze a wealth of phylogenetic, biochemical, structural, genetic and physiological data about this extensively studied but still insufficiently understood factor. We do so using a comparative and, wherever possible, synthetic approach, by confronting observations from diverse groups of bacteria and eukaryotic organelles (mitochondria and chloroplasts). The emerging consensus posits that Era intervenes relatively early in the small subunit biogenesis and is essential for the proper shaping of the platform which, in its turn, is a prerequisite for efficient translation. The timing of Era action on the ribosome is defined by its interactions with guanosine nucleotides [GTP, GDP, (p)ppGpp], ribosomal RNA, and likely other factors that trigger or delay its GTPase activity. As a critical nexus of the small subunit biogenesis, Era is subject to sophisticated regulatory mechanisms at the transcriptional, post-transcriptional, and post-translational levels. Failure of these mechanisms or a deficiency in Era function entail dramatic generalized consequences for the protein synthesis and far-reaching, pleiotropic effects on the organism physiology, such as the Perrault syndrome in humans.
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Affiliation(s)
- Christelle Gruffaz
- UMR7156- Génétique Moléculaire, Génomique, Microbiologie (GMGM), University of Strasbourg, Centre National de la Recherche Scientifique (CNRS), Strasbourg, France
| | - Alexandre Smirnov
- UMR7156- Génétique Moléculaire, Génomique, Microbiologie (GMGM), University of Strasbourg, Centre National de la Recherche Scientifique (CNRS), Strasbourg, France
- University of Strasbourg Institute for Advanced Study (USIAS), Strasbourg, France
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6
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Remes C, Khawaja A, Pearce SF, Dinan AM, Gopalakrishna S, Cipullo M, Kyriakidis V, Zhang J, Dopico XC, Yukhnovets O, Atanassov I, Firth AE, Cooperman B, Rorbach J. Translation initiation of leaderless and polycistronic transcripts in mammalian mitochondria. Nucleic Acids Res 2023; 51:891-907. [PMID: 36629253 PMCID: PMC9881170 DOI: 10.1093/nar/gkac1233] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 11/11/2022] [Accepted: 12/09/2022] [Indexed: 01/12/2023] Open
Abstract
The synthesis of mitochondrial OXPHOS complexes is central to cellular metabolism, yet many molecular details of mitochondrial translation remain elusive. It has been commonly held view that translation initiation in human mitochondria proceeded in a manner similar to bacterial systems, with the mitoribosomal small subunit bound to the initiation factors, mtIF2 and mtIF3, along with initiator tRNA and an mRNA. However, unlike in bacteria, most human mitochondrial mRNAs lack 5' leader sequences that can mediate small subunit binding, raising the question of how leaderless mRNAs are recognized by mitoribosomes. By using novel in vitro mitochondrial translation initiation assays, alongside biochemical and genetic characterization of cellular knockouts of mitochondrial translation factors, we describe unique features of translation initiation in human mitochondria. We show that in vitro, leaderless mRNA transcripts can be loaded directly onto assembled 55S mitoribosomes, but not onto the mitoribosomal small subunit (28S), in a manner that requires initiator fMet-tRNAMet binding. In addition, we demonstrate that in human cells and in vitro, mtIF3 activity is not required for translation of leaderless mitochondrial transcripts but is essential for translation of ATP6 in the case of the bicistronic ATP8/ATP6 transcript. Furthermore, we show that mtIF2 is indispensable for mitochondrial protein synthesis. Our results demonstrate an important evolutionary divergence of the mitochondrial translation system and further our fundamental understanding of a process central to eukaryotic metabolism.
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Affiliation(s)
- Cristina Remes
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anas Khawaja
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Stockholm 17165, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Sarah F Pearce
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Stockholm 17165, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Adam M Dinan
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Shreekara Gopalakrishna
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Stockholm 17165, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Miriam Cipullo
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Stockholm 17165, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Vasileios Kyriakidis
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Stockholm 17165, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Jingdian Zhang
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Stockholm 17165, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Xaquin Castro Dopico
- Department of Microbiology, Tumor & Cell Biology, Karolinska Institutet, Stockholm 171 77, Sweden
| | - Olessya Yukhnovets
- RWTH Aachen, I. Physikalisches Institut (IA), Aachen, Germany
- Forschungszentrum Jülich, Institute of Complex Systems ICS-5, Jülich, Germany
| | - Ilian Atanassov
- Proteomics Core Facility, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Andrew E Firth
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Barry Cooperman
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Stockholm 17165, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
- STIAS: Stellenbosch Institute for Advanced Study at Stellenbosch University, Marais Rd, Stellenbosch 7600, South Africa
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7
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Conor Moran J, Del'Olio S, Choi A, Zhong H, Barrientos A. Mitoribosome Biogenesis. Methods Mol Biol 2023; 2661:23-51. [PMID: 37166630 PMCID: PMC10639111 DOI: 10.1007/978-1-0716-3171-3_3] [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] [Indexed: 05/12/2023]
Abstract
Mitoribosome biogenesis is a complex and energetically costly process that involves RNA elements encoded in the mitochondrial genome and mitoribosomal proteins most frequently encoded in the nuclear genome. The process is catalyzed by extra-ribosomal proteins, nucleus-encoded assembly factors that act in all stages of the assembly process to coordinate the processing and maturation of ribosomal RNAs with the hierarchical association of ribosomal proteins. Biochemical studies and recent cryo-EM structures of mammalian mitoribosomes have provided hints regarding their assembly. In this general concept chapter, we will briefly describe the current knowledge, mainly regarding the mammalian mitoribosome biogenesis pathway and factors involved, and will emphasize the biological sources and approaches that have been applied to advance the field.
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Affiliation(s)
- J Conor Moran
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Samuel Del'Olio
- Department of Molecular and Cellular Pharmacology, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Austin Choi
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Hui Zhong
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Antoni Barrientos
- Department of Neurology and Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, FL, USA.
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8
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Jeandard D, Smirnova A, Fasemore AM, Coudray L, Entelis N, Förstner K, Tarassov I, Smirnov A. CoLoC-seq probes the global topology of organelle transcriptomes. Nucleic Acids Res 2022; 51:e16. [PMID: 36537202 PMCID: PMC9943681 DOI: 10.1093/nar/gkac1183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022] Open
Abstract
Proper RNA localisation is essential for physiological gene expression. Various kinds of genome-wide approaches permit to comprehensively profile subcellular transcriptomes. Among them, cell fractionation methods, that couple RNase treatment of isolated organelles to the sequencing of protected transcripts, remain most widely used, mainly because they do not require genetic modification of the studied system and can be easily implemented in any cells or tissues, including in non-model species. However, they suffer from numerous false-positives since incompletely digested contaminant RNAs can still be captured and erroneously identified as resident transcripts. Here we introduce Controlled Level of Contamination coupled to deep sequencing (CoLoC-seq) as a new subcellular transcriptomics approach that efficiently bypasses this caveat. CoLoC-seq leverages classical enzymatic kinetics and tracks the depletion dynamics of transcripts in a gradient of an exogenously added RNase, with or without organellar membranes. By means of straightforward mathematical modelling, CoLoC-seq infers the localisation topology of RNAs and robustly distinguishes between genuinely resident, luminal transcripts and merely abundant surface-attached contaminants. Our generic approach performed well on human mitochondria and is in principle applicable to other membrane-bounded organelles, including plastids, compartments of the vacuolar system, extracellular vesicles, and viral particles.
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Affiliation(s)
| | | | | | - Léna Coudray
- UMR7156 – Génétique Moléculaire, Génomique, Microbiologie (GMGM), University of Strasbourg, CNRS, Strasbourg, F-67000, France
| | - Nina Entelis
- UMR7156 – Génétique Moléculaire, Génomique, Microbiologie (GMGM), University of Strasbourg, CNRS, Strasbourg, F-67000, France
| | - Konrad U Förstner
- ZB MED – Information Centre for Life Sciences, Cologne, D-50931, Germany,TH Köln – University of Applied Sciences, Faculty of Information Science and Communication Studies, Institute of Information Science, Cologne, D-50678, Germany
| | - Ivan Tarassov
- UMR7156 – Génétique Moléculaire, Génomique, Microbiologie (GMGM), University of Strasbourg, CNRS, Strasbourg, F-67000, France
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9
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How RNases Shape Mitochondrial Transcriptomes. Int J Mol Sci 2022; 23:ijms23116141. [PMID: 35682820 PMCID: PMC9181182 DOI: 10.3390/ijms23116141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 05/24/2022] [Accepted: 05/25/2022] [Indexed: 11/17/2022] Open
Abstract
Mitochondria are the power houses of eukaryote cells. These endosymbiotic organelles of prokaryote origin are considered as semi-autonomous since they have retained a genome and fully functional gene expression mechanisms. These pathways are particularly interesting because they combine features inherited from the bacterial ancestor of mitochondria with characteristics that appeared during eukaryote evolution. RNA biology is thus particularly diverse in mitochondria. It involves an unexpectedly vast array of factors, some of which being universal to all mitochondria and others being specific from specific eukaryote clades. Among them, ribonucleases are particularly prominent. They play pivotal functions such as the maturation of transcript ends, RNA degradation and surveillance functions that are required to attain the pool of mature RNAs required to synthesize essential mitochondrial proteins such as respiratory chain proteins. Beyond these functions, mitochondrial ribonucleases are also involved in the maintenance and replication of mitochondrial DNA, and even possibly in the biogenesis of mitochondrial ribosomes. The diversity of mitochondrial RNases is reviewed here, showing for instance how in some cases a bacterial-type enzyme was kept in some eukaryotes, while in other clades, eukaryote specific enzymes were recruited for the same function.
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10
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Babu VMP, Sankari S, Ghosal A, Walker GC. A Mutant Era GTPase Suppresses Phenotypes Caused by Loss of Highly Conserved YbeY Protein in Escherichia coli. Front Microbiol 2022; 13:896075. [PMID: 35663862 PMCID: PMC9159920 DOI: 10.3389/fmicb.2022.896075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/13/2022] [Indexed: 12/03/2022] Open
Abstract
Ribosome assembly is a complex fundamental cellular process that involves assembling multiple ribosomal proteins and several ribosomal RNA species in a highly coordinated yet flexible and resilient manner. The highly conserved YbeY protein is a single-strand specific endoribonuclease, important for ribosome assembly, 16S rRNA processing, and ribosome quality control. In Escherichia coli, ybeY deletion results in pleiotropic phenotypes including slow growth, temperature sensitivity, accumulation of precursors of 16S rRNA, and impaired formation of fully assembled 70S subunits. Era, an essential highly conserved GTPase protein, interacts with many ribosomal proteins, and its depletion results in ribosome assembly defects. YbeY has been shown to interact with Era together with ribosomal protein S11. In this study, we have analyzed a suppressor mutation, era(T99I), that can partially suppress a subset of the multiple phenotypes of ybeY deletion. The era(T99I) allele was able to improve 16S rRNA processing and ribosome assembly at 37°C. However, it failed to suppress the temperature sensitivity and did not improve 16S rRNA stability. The era(T99I) allele was also unable to improve the 16S rRNA processing defects caused by the loss of ribosome maturation factors. We also show that era(T99I) increases the GroEL levels in the 30S ribosome fractions independent of YbeY. We propose that the mechanism of suppression is that the changes in Era's structure caused by the era(T99I) mutation affect its GTP/GDP cycle in a way that increases the half-life of RNA binding to Era, thereby facilitating alternative processing of the 16S RNA precursor. Taken together, this study offers insights into the role of Era and YbeY in ribosome assembly and 16S rRNA processing events.
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Affiliation(s)
| | | | | | - Graham C. Walker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States
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11
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Yu F, Li JL, Feng WR, Tang YK, Su SY, Xu P, Zhong H. Heat Shock Procedure Affects Cell Division-Associated Genes in Gynogenetic Manipulation. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2022; 24:354-365. [PMID: 35305189 DOI: 10.1007/s10126-022-10112-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
Heat shock procedure is crucial for gynogenetic manipulation leading to diploidization of the maternal genomes; however, the underlying molecular mechanism especially the transcriptomic changes during this procedure has still not been unveiled yet. Here, the artificial gynogenesis of zebrafish (Danio rerio) using inactivated sperm from rare minnow (Gobiocypris rarus) was conducted. We found that artificial gynogenetic manipulation, including pseudo-fertilization and heat shock, decreased hatching rates, whereas heat shock treatment alone had medium hatching rates. The first cleavage changed the expression of genes associated with RNA transcription and protein synthesis. A co-expression network regulated by hub genes GIT1, Sepsecs, and FLNB was significantly correlated with heat shock procedure. The cyclin family and cyclin-dependent kinase-related genes were lowly expressed in embryos from gynogenetic zebrafish, and genes involved in controlling the cell cycle and genomic stability were significantly altered by the gynogenetic treatment. Our results show the effects of artificial gynogenesis on embryos and describe changes in gene expression that suggest drastic changes take place in cell division by heat shock procedure. These findings will contribute to an understanding of the molecular basis for germplasm improving, including the purifying effect and allogynogenetic biological effect by gynogenesis.
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Affiliation(s)
- Fan Yu
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China
| | - Jian-Lin Li
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China
| | - Wen-Rong Feng
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China
| | - Yong-Kai Tang
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China
| | - Sheng-Yan Su
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China
| | - Pao Xu
- Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China.
| | - Huan Zhong
- Hunan Research Center of Engineering Technology for Utilization of Distinctive Aquatic Resource, Hunan Agricultural University, Changsha, 410128, China.
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12
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Andrews ESV, Patrick WM. The hypothesized role of YbeZ in 16S rRNA maturation. Arch Microbiol 2022; 204:114. [PMID: 34984547 DOI: 10.1007/s00203-021-02739-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 11/28/2022]
Abstract
Ribosomes are the protein production machines in all living cells. Yet in contrast to our understanding of how the ribosome translates DNA information into life, the steps involved in ribosome biogenesis, the assembly of the ribosomal RNA (rRNA) and protein molecules that make up the ribosome, remain incomplete. YbeY is considered one of the most physiologically critical endoribonucleases and is implicated in numerous roles involving RNA including 16S rRNA maturation, yet our existing knowledge of its biochemical function fails to explain the phenotypes that manifest when it is lost. In bacteria, it is common for functionally associated genes to be found co-localized in the genome. Across phylogenetically diverse bacteria, the gene encoding ybeZ, encoding a PhoH domain protein, sits adjacent to ybeY. Recent experimental evidence has shown that PhoH domains are RNA helicases, suggesting that this is also the role of YbeZ. The role of an RNA helicase to support the function of YbeY would help explain its reported biochemistry; therefore, we propose a model for the function of YbeZ in 16S rRNA maturation, linking it with the most recent hypotheses on the function of YbeY, that YbeY together with other ribosomal proteins, and ribosome-associated proteins, plays a role in the biogenesis of the small ribosomal subunit. Our model provides a testable hypothesis to resolve the outstanding details surrounding ribosome biogenesis in bacteria.
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Affiliation(s)
- Emma S V Andrews
- Centre for Biodiscovery, School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand.
| | - Wayne M Patrick
- Centre for Biodiscovery, School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
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13
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Waltz F, Salinas-Giegé T, Englmeier R, Meichel H, Soufari H, Kuhn L, Pfeffer S, Förster F, Engel BD, Giegé P, Drouard L, Hashem Y. How to build a ribosome from RNA fragments in Chlamydomonas mitochondria. Nat Commun 2021; 12:7176. [PMID: 34887394 PMCID: PMC8660880 DOI: 10.1038/s41467-021-27200-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 11/08/2021] [Indexed: 01/12/2023] Open
Abstract
Mitochondria are the powerhouse of eukaryotic cells. They possess their own gene expression machineries where highly divergent and specialized ribosomes, named hereafter mitoribosomes, translate the few essential messenger RNAs still encoded by mitochondrial genomes. Here, we present a biochemical and structural characterization of the mitoribosome in the model green alga Chlamydomonas reinhardtii, as well as a functional study of some of its specific components. Single particle cryo-electron microscopy resolves how the Chlamydomonas mitoribosome is assembled from 13 rRNA fragments encoded by separate non-contiguous gene pieces. Additional proteins, mainly OPR, PPR and mTERF helical repeat proteins, are found in Chlamydomonas mitoribosome, revealing the structure of an OPR protein in complex with its RNA binding partner. Targeted amiRNA silencing indicates that these ribosomal proteins are required for mitoribosome integrity. Finally, we use cryo-electron tomography to show that Chlamydomonas mitoribosomes are attached to the inner mitochondrial membrane via two contact points mediated by Chlamydomonas-specific proteins. Our study expands our understanding of mitoribosome diversity and the various strategies these specialized molecular machines adopt for membrane tethering.
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Affiliation(s)
- Florent Waltz
- Institut Européen de Chimie et Biologie, U1212 Inserm, Université de Bordeaux, 2 rue R. Escarpit, 33600, Pessac, France
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du général Zimmer, 67084, Strasbourg, France
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Thalia Salinas-Giegé
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du général Zimmer, 67084, Strasbourg, France
| | - Robert Englmeier
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - Herrade Meichel
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du général Zimmer, 67084, Strasbourg, France
| | - Heddy Soufari
- Institut Européen de Chimie et Biologie, U1212 Inserm, Université de Bordeaux, 2 rue R. Escarpit, 33600, Pessac, France
| | - Lauriane Kuhn
- Plateforme protéomique Strasbourg Esplanade FRC1589 du CNRS, Université de Strasbourg, 67084, Strasbourg, France
| | - Stefan Pfeffer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany
| | - Friedrich Förster
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - Benjamin D Engel
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
- Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Philippe Giegé
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du général Zimmer, 67084, Strasbourg, France.
| | - Laurence Drouard
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du général Zimmer, 67084, Strasbourg, France.
| | - Yaser Hashem
- Institut Européen de Chimie et Biologie, U1212 Inserm, Université de Bordeaux, 2 rue R. Escarpit, 33600, Pessac, France.
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14
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Oxidative Stress Response in Pseudomonas aeruginosa. Pathogens 2021; 10:pathogens10091187. [PMID: 34578219 PMCID: PMC8466533 DOI: 10.3390/pathogens10091187] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/06/2021] [Accepted: 09/08/2021] [Indexed: 12/17/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative environmental and human opportunistic pathogen highly adapted to many different environmental conditions. It can cause a wide range of serious infections, including wounds, lungs, the urinary tract, and systemic infections. The high versatility and pathogenicity of this bacterium is attributed to its genomic complexity, the expression of several virulence factors, and its intrinsic resistance to various antimicrobials. However, to thrive and establish infection, P. aeruginosa must overcome several barriers. One of these barriers is the presence of oxidizing agents (e.g., hydrogen peroxide, superoxide, and hypochlorous acid) produced by the host immune system or that are commonly used as disinfectants in a variety of different environments including hospitals. These agents damage several cellular molecules and can cause cell death. Therefore, bacteria adapt to these harsh conditions by altering gene expression and eliciting several stress responses to survive under oxidative stress. Here, we used PubMed to evaluate the current knowledge on the oxidative stress responses adopted by P. aeruginosa. We will describe the genes that are often differently expressed under oxidative stress conditions, the pathways and proteins employed to sense and respond to oxidative stress, and how these changes in gene expression influence pathogenicity and the virulence of P. aeruginosa. Understanding these responses and changes in gene expression is critical to controlling bacterial pathogenicity and developing new therapeutic agents.
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15
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Hilander T, Jackson CB, Robciuc M, Bashir T, Zhao H. The roles of assembly factors in mammalian mitoribosome biogenesis. Mitochondrion 2021; 60:70-84. [PMID: 34339868 DOI: 10.1016/j.mito.2021.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 02/08/2023]
Abstract
As ancient bacterial endosymbionts of eukaryotic cells, mitochondria have retained their own circular DNA as well as protein translation system including mitochondrial ribosomes (mitoribosomes). In recent years, methodological advancements in cryoelectron microscopy and mass spectrometry have revealed the extent of the evolutionary divergence of mitoribosomes from their bacterial ancestors and their adaptation to the synthesis of 13 mitochondrial DNA encoded oxidative phosphorylation complex subunits. In addition to the structural data, the first assembly pathway maps of mitoribosomes have started to emerge and concomitantly also the assembly factors involved in this process to achieve fully translational competent particles. These transiently associated factors assist in the intricate assembly process of mitoribosomes by enhancing protein incorporation, ribosomal RNA folding and modification, and by blocking premature or non-native protein binding, for example. This review focuses on summarizing the current understanding of the known mammalian mitoribosome assembly factors and discussing their possible roles in the assembly of small or large mitoribosomal subunits.
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Affiliation(s)
- Taru Hilander
- Faculty of Biological and Environmental Sciences, University of Helsinki, Finland.
| | - Christopher B Jackson
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Finland.
| | - Marius Robciuc
- Faculty of Biological and Environmental Sciences, University of Helsinki, Finland
| | - Tanzeela Bashir
- Faculty of Biological and Environmental Sciences, University of Helsinki, Finland
| | - Hongxia Zhao
- Faculty of Biological and Environmental Sciences, University of Helsinki, Finland; Key Laboratory of Stem Cell and Biopharmaceutical Technology, School of Life Sciences, Guangxi Normal University, Guangxi, China.
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16
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D’Souza AR, Van Haute L, Powell CA, Mutti CD, Páleníková P, Rebelo-Guiomar P, Rorbach J, Minczuk M. YbeY is required for ribosome small subunit assembly and tRNA processing in human mitochondria. Nucleic Acids Res 2021; 49:5798-5812. [PMID: 34037799 PMCID: PMC8191802 DOI: 10.1093/nar/gkab404] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/20/2021] [Accepted: 05/06/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondria contain their own translation apparatus which enables them to produce the polypeptides encoded in their genome. The mitochondrially-encoded RNA components of the mitochondrial ribosome require various post-transcriptional processing steps. Additional protein factors are required to facilitate the biogenesis of the functional mitoribosome. We have characterized a mitochondrially-localized protein, YbeY, which interacts with the assembling mitoribosome through the small subunit. Loss of YbeY leads to a severe reduction in mitochondrial translation and a loss of cell viability, associated with less accurate mitochondrial tRNASer(AGY) processing from the primary transcript and a defect in the maturation of the mitoribosomal small subunit. Our results suggest that YbeY performs a dual, likely independent, function in mitochondria being involved in precursor RNA processing and mitoribosome biogenesis. Issue Section: Nucleic Acid Enzymes.
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Affiliation(s)
- Aaron R D’Souza
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Lindsey Van Haute
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Christopher A Powell
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Christian D Mutti
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Petra Páleníková
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Pedro Rebelo-Guiomar
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Joanna Rorbach
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Michal Minczuk
- To whom correspondence should be addressed. Tel: +44 122 325 2750;
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17
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Luo Y, Wang Y, Huang Y. Schizosaccharomyces pombe Ppr10 and Mpa1 together mediate mitochondrial translational initiation. J Biol Chem 2021; 297:100869. [PMID: 34119521 PMCID: PMC8258696 DOI: 10.1016/j.jbc.2021.100869] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/04/2021] [Accepted: 06/09/2021] [Indexed: 12/26/2022] Open
Abstract
Pentatricopeptide repeat (PPR) proteins are a large family of proteins that act primarily at different posttranscriptional steps of organellar gene expression. We have previously found that the Schizosaccharomyces pombe PPR protein mpal10 interacts with mitochondrial translational activator Mpa1, and both are essential for mitochondrial protein synthesis. However, it is unclear how these two proteins function in mitochondrial protein synthesis in S. pombe. In this study, we further investigated the role of Ppr10 and Mpa1 in mitochondrial protein synthesis. Mitochondrial translational initiation requires two initiation factors, Mti2 and Mti3, which bind to the small subunit of the mitochondrial ribosome (mt-SSU) during the formation of the mitochondrial translational initiation complex. Using sucrose gradient sedimentation analysis, we found that disruption of ppr10, mpa1, or the PPR motifs in Ppr10 impairs the association of Mti2 and Mti3 with the mt-SSU, suggesting that both Ppr10 and Mpa1 may be required for the interaction of Mti2 and Mti3 with the mt-SSU during the assembly of mitochondrial translational initiation complex. Loss of Ppr10 perturbs the association of mitochondrially encoded cytochrome b (cob1) and cytochrome c oxidase subunit 1 (cox1) mRNAs with assembled mitochondrial ribosomes. Proteomic analysis revealed that a fraction of Ppr10 and Mpa1 copurified with a subset of mitoribosomal proteins. The PPR motifs of Ppr10 are necessary for its interaction with Mpa1 and that disruption of these PPR motifs impairs mitochondrial protein synthesis. Our results suggest that Ppr10 and Mpa1 function together to mediate mitochondrial translational initiation.
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Affiliation(s)
- Ying Luo
- Jiangsu Key Laboratory for Microbes and Genomics, School of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Yirong Wang
- Jiangsu Key Laboratory for Microbes and Genomics, School of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Ying Huang
- Jiangsu Key Laboratory for Microbes and Genomics, School of Life Sciences, Nanjing Normal University, Nanjing, China.
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18
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YbeY, éminence grise of ribosome biogenesis. Biochem Soc Trans 2021; 49:727-745. [PMID: 33929506 DOI: 10.1042/bst20200669] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 12/30/2022]
Abstract
YbeY is an ultraconserved small protein belonging to the unique heritage shared by most existing bacteria and eukaryotic organelles of bacterial origin, mitochondria and chloroplasts. Studied in more than a dozen of evolutionarily distant species, YbeY is invariably critical for cellular physiology. However, the exact mechanisms by which it exerts such penetrating influence are not completely understood. In this review, we attempt a transversal analysis of the current knowledge about YbeY, based on genetic, structural, and biochemical data from a wide variety of models. We propose that YbeY, in association with the ribosomal protein uS11 and the assembly GTPase Era, plays a critical role in the biogenesis of the small ribosomal subunit, and more specifically its platform region, in diverse genetic systems of bacterial type.
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19
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Shidal C, Shu X, Wu J, Wang J, Huang S, Long J, Bauer JA, Ping J, Guo X, Zheng W, Shu XO, Cai Q. Functional Genomic Analyses of the 21q22.3 Locus Identifying Functional Variants and Candidate Gene YBEY for Breast Cancer Risk. Cancers (Basel) 2021; 13:cancers13092037. [PMID: 33922500 PMCID: PMC8122893 DOI: 10.3390/cancers13092037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 12/13/2022] Open
Abstract
Simple Summary Previous research has revealed a genetic predisposition to breast carcinogenesis. Thus, identifying causal genetic variants and their associated gene networks may improve breast cancer diagnostics and risk assessment. Our study investigated YBEY, an uncharacterized gene in humans, and its functions in breast cancer risk and progression. We identified two genetic variants associated with YBEY expression that may have causal functions in breast cancer risk. We performed in vitro functional assays using MCF-7, T47D, and MDA-MB-231 breast cancer cell lines and showed that knockdown of YBEY expression significantly inhibited proliferation, colony formation, and invasion/migration. We utilized RNA sequencing to identify gene networks associated with YBEY knockdown including inflammation and metabolic pathways. Further, we used data available in The Cancer Genome Atlas to explore trends in YBEY expression patterns in normal and tumor tissues. Our study provides a role for YBEY in breast carcinogenesis, and further studies investigating its mechanistic functions are warranted. Abstract We previously identified a locus at 21q22.3, tagged by the single nucleotide polymorphism (SNP) rs35418111, being associated with breast cancer risk at a genome-wide significance level; however, the underlying causal functional variants and gene(s) responsible for this association are unknown. We performed functional genomic analyses to identify potential functional variants and target genes that may mediate this association. Functional annotation for SNPs in high linkage disequilibrium (LD, r2 > 0.8) with rs35418111 in Asians showed evidence of promoter and/or enhancer activities, including rs35418111, rs2078203, rs8134832, rs57385578, and rs8126917. These five variants were assessed for interactions with nuclear proteins by electrophoretic mobility shift assays. Our results showed that the risk alleles for rs2078203 and rs35418111 altered DNA-protein interaction patterns. Cis-expression quantitative loci (cis-eQTL) analysis, using data from the Genotype-Tissue Expression database (GTEx) European-ancestry female normal breast tissue, indicated that the risk allele of rs35418111 was associated with a decreased expression of the YBEY gene, a relatively uncharacterized endoribonuclease in humans. We investigated the biological effects of YBEY on breast cancer cell lines by transient knock-down of YBEY expression in MCF-7, T47D, and MDA-MB-231 cell lines. Knockdown of YBEY mRNA in breast cancer cell lines consistently decreased cell proliferation, colony formation, and migration/invasion, regardless of estrogen receptor status. We performed RNA sequencing in MDA-MB-231 cells transfected with siRNA targeting YBEY and subsequent gene set enrichment analysis to identify gene networks associated with YBEY knockdown. These data indicated YBEY was involved in networks associated with inflammation and metabolism. Finally, we showed trends in YBEY expression patterns in breast tissues from The Cancer Genome Atlas (TCGA); early-stage breast cancers had elevated YBEY expression compared with normal tissue, but significantly decreased expression in late-stage disease. Our study provides evidence of a significant role for the human YBEY gene in breast cancer pathogenesis and the association between the rs35418111/21q22.3 locus and breast cancer risk, which may be mediated through functional SNPs, rs35418111 and rs2078203, that regulate expression of YBEY.
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Affiliation(s)
- Chris Shidal
- Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN 37203, USA; (C.S.); (X.S.); (J.W.); (J.W.); (S.H.); (J.L.); (J.P.); (X.G.); (W.Z.); (X.-O.S.)
| | - Xiang Shu
- Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN 37203, USA; (C.S.); (X.S.); (J.W.); (J.W.); (S.H.); (J.L.); (J.P.); (X.G.); (W.Z.); (X.-O.S.)
- Memorial Sloan Kettering Cancer Center, Department of Epidemiology & Biostatistics, New York, NY 10075, USA
| | - Jie Wu
- Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN 37203, USA; (C.S.); (X.S.); (J.W.); (J.W.); (S.H.); (J.L.); (J.P.); (X.G.); (W.Z.); (X.-O.S.)
| | - Jifeng Wang
- Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN 37203, USA; (C.S.); (X.S.); (J.W.); (J.W.); (S.H.); (J.L.); (J.P.); (X.G.); (W.Z.); (X.-O.S.)
| | - Shuya Huang
- Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN 37203, USA; (C.S.); (X.S.); (J.W.); (J.W.); (S.H.); (J.L.); (J.P.); (X.G.); (W.Z.); (X.-O.S.)
- Department of Breast Surgery, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250033, China
| | - Jirong Long
- Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN 37203, USA; (C.S.); (X.S.); (J.W.); (J.W.); (S.H.); (J.L.); (J.P.); (X.G.); (W.Z.); (X.-O.S.)
| | - Joshua A. Bauer
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37203, USA;
| | - Jie Ping
- Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN 37203, USA; (C.S.); (X.S.); (J.W.); (J.W.); (S.H.); (J.L.); (J.P.); (X.G.); (W.Z.); (X.-O.S.)
| | - Xingyi Guo
- Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN 37203, USA; (C.S.); (X.S.); (J.W.); (J.W.); (S.H.); (J.L.); (J.P.); (X.G.); (W.Z.); (X.-O.S.)
| | - Wei Zheng
- Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN 37203, USA; (C.S.); (X.S.); (J.W.); (J.W.); (S.H.); (J.L.); (J.P.); (X.G.); (W.Z.); (X.-O.S.)
| | - Xiao-Ou Shu
- Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN 37203, USA; (C.S.); (X.S.); (J.W.); (J.W.); (S.H.); (J.L.); (J.P.); (X.G.); (W.Z.); (X.-O.S.)
| | - Qiuyin Cai
- Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Department of Medicine, Division of Epidemiology, Vanderbilt University School of Medicine, Nashville, TN 37203, USA; (C.S.); (X.S.); (J.W.); (J.W.); (S.H.); (J.L.); (J.P.); (X.G.); (W.Z.); (X.-O.S.)
- Correspondence: ; Tel.: +1-615-936-1351; Fax: +1-615-936-8291
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20
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Human Mitoribosome Biogenesis and Its Emerging Links to Disease. Int J Mol Sci 2021; 22:ijms22083827. [PMID: 33917098 PMCID: PMC8067846 DOI: 10.3390/ijms22083827] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/20/2022] Open
Abstract
Mammalian mitochondrial ribosomes (mitoribosomes) synthesize a small subset of proteins, which are essential components of the oxidative phosphorylation machinery. Therefore, their function is of fundamental importance to cellular metabolism. The assembly of mitoribosomes is a complex process that progresses through numerous maturation and protein-binding events coordinated by the actions of several assembly factors. Dysregulation of mitoribosome production is increasingly recognized as a contributor to metabolic and neurodegenerative diseases. In recent years, mutations in multiple components of the mitoribosome assembly machinery have been associated with a range of human pathologies, highlighting their importance to cell function and health. Here, we provide a review of our current understanding of mitoribosome biogenesis, highlighting the key factors involved in this process and the growing number of mutations in genes encoding mitoribosomal RNAs, proteins, and assembly factors that lead to human disease.
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21
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Blackout in the powerhouse: clinical phenotypes associated with defects in the assembly of OXPHOS complexes and the mitoribosome. Biochem J 2021; 477:4085-4132. [PMID: 33151299 PMCID: PMC7657662 DOI: 10.1042/bcj20190767] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 09/29/2020] [Accepted: 10/05/2020] [Indexed: 12/26/2022]
Abstract
Mitochondria produce the bulk of the energy used by almost all eukaryotic cells through oxidative phosphorylation (OXPHOS) which occurs on the four complexes of the respiratory chain and the F1–F0 ATPase. Mitochondrial diseases are a heterogenous group of conditions affecting OXPHOS, either directly through mutation of genes encoding subunits of OXPHOS complexes, or indirectly through mutations in genes encoding proteins supporting this process. These include proteins that promote assembly of the OXPHOS complexes, the post-translational modification of subunits, insertion of cofactors or indeed subunit synthesis. The latter is important for all 13 of the proteins encoded by human mitochondrial DNA, which are synthesised on mitochondrial ribosomes. Together the five OXPHOS complexes and the mitochondrial ribosome are comprised of more than 160 subunits and many more proteins support their biogenesis. Mutations in both nuclear and mitochondrial genes encoding these proteins have been reported to cause mitochondrial disease, many leading to defective complex assembly with the severity of the assembly defect reflecting the severity of the disease. This review aims to act as an interface between the clinical and basic research underpinning our knowledge of OXPHOS complex and ribosome assembly, and the dysfunction of this process in mitochondrial disease.
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22
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Smirnova A, Richert L, Smirnov A, Mély Y, Tarassov I. Suborganellar Localization of Mitochondrial Proteins and Transcripts in Human Cells. Methods Mol Biol 2021; 2277:157-173. [PMID: 34080151 DOI: 10.1007/978-1-0716-1270-5_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Mitochondria have complex ultrastructure which includes continuous subcompartments, such as matrix, intermembrane space, and two membranes, as well as focal structures, such as nucleoids, RNA granules, and mitoribosomes. Comprehensive studies of the spatial distribution of proteins and RNAs inside the mitochondria are necessary to understand organellar gene expression processes and macromolecule targeting pathways. Here we give examples of distribution analysis of mitochondrial proteins and transcripts by conventional microscopy and the super-resolution technique 3D STORM. We provide detailed protocols and discuss limitations of immunolabeling of mitochondrial proteins and newly synthesized mitochondrial RNAs by bromouridine incorporation and single-molecule RNA FISH in hepatocarcinoma cells.
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Affiliation(s)
- Anna Smirnova
- UMR 7156 - Molecular Genetics, Genomics, Microbiology (GMGM), University of Strasbourg/CNRS, Strasbourg, France
| | - Ludovic Richert
- UMR 7021 - Laboratory of Biophotonics and Pharmacology (LBP), University of Strasbourg/CNRS, Illkirch, France
| | - Alexandre Smirnov
- UMR 7156 - Molecular Genetics, Genomics, Microbiology (GMGM), University of Strasbourg/CNRS, Strasbourg, France
| | - Yves Mély
- UMR 7021 - Laboratory of Biophotonics and Pharmacology (LBP), University of Strasbourg/CNRS, Illkirch, France
| | - Ivan Tarassov
- UMR 7156 - Molecular Genetics, Genomics, Microbiology (GMGM), University of Strasbourg/CNRS, Strasbourg, France.
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Ferrari A, Del'Olio S, Barrientos A. The Diseased Mitoribosome. FEBS Lett 2020; 595:1025-1061. [PMID: 33314036 DOI: 10.1002/1873-3468.14024] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/03/2020] [Accepted: 12/06/2020] [Indexed: 12/17/2022]
Abstract
Mitochondria control life and death in eukaryotic cells. Harboring a unique circular genome, a by-product of an ancient endosymbiotic event, mitochondria maintains a specialized and evolutionary divergent protein synthesis machinery, the mitoribosome. Mitoribosome biogenesis depends on elements encoded in both the mitochondrial genome (the RNA components) and the nuclear genome (all ribosomal proteins and assembly factors). Recent cryo-EM structures of mammalian mitoribosomes have illuminated their composition and provided hints regarding their assembly and elusive mitochondrial translation mechanisms. A growing body of literature involves the mitoribosome in inherited primary mitochondrial disorders. Mutations in genes encoding mitoribosomal RNAs, proteins, and assembly factors impede mitoribosome biogenesis, causing protein synthesis defects that lead to respiratory chain failure and mitochondrial disorders such as encephalo- and cardiomyopathy, deafness, neuropathy, and developmental delays. In this article, we review the current fundamental understanding of mitoribosome assembly and function, and the clinical landscape of mitochondrial disorders driven by mutations in mitoribosome components and assembly factors, to portray how basic and clinical studies combined help us better understand both mitochondrial biology and medicine.
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Affiliation(s)
- Alberto Ferrari
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA
| | - Samuel Del'Olio
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA.,Molecular and Cellular Pharmacology Graduate Program, University of Miami Miller School of Medicine, FL, USA
| | - Antoni Barrientos
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA.,Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, FL, USA
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Laptev I, Dontsova O, Sergiev P. Epitranscriptomics of Mammalian Mitochondrial Ribosomal RNA. Cells 2020; 9:cells9102181. [PMID: 32992603 PMCID: PMC7600485 DOI: 10.3390/cells9102181] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/20/2020] [Accepted: 09/23/2020] [Indexed: 12/16/2022] Open
Abstract
Modified nucleotides are present in all ribosomal RNA molecules. Mitochondrial ribosomes are unique to have a set of methylated residues that includes universally conserved ones, those that could be found either in bacterial or in archaeal/eukaryotic cytosolic ribosomes and those that are present exclusively in mitochondria. A single pseudouridine within the mt-rRNA is located in the peptidyltransferase center at a position similar to that in bacteria. After recent completion of the list of enzymes responsible for the modification of mammalian mitochondrial rRNA it became possible to summarize an evolutionary history, functional role of mt-rRNA modification enzymes and an interplay of the mt-rRNA modification and mitoribosome assembly process, which is a goal of this review.
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Affiliation(s)
- Ivan Laptev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (I.L.); (O.D.)
| | - Olga Dontsova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (I.L.); (O.D.)
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Skolkovo, 143028 Moscow Region, Russia
- Department of Chemistry, Lomonosov Moscow State University, 119992 Moscow, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia
| | - Petr Sergiev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (I.L.); (O.D.)
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Skolkovo, 143028 Moscow Region, Russia
- Department of Chemistry, Lomonosov Moscow State University, 119992 Moscow, Russia
- Institute of Functional Genomics, Lomonosov Moscow State University, 119992 Moscow, Russia
- Correspondence: ; Tel.: +7-495-939-5418
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