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Sridhara S. Multiple structural flavors of RNase P in precursor tRNA processing. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1835. [PMID: 38479802 DOI: 10.1002/wrna.1835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 01/26/2024] [Accepted: 01/29/2024] [Indexed: 06/06/2024]
Abstract
The precursor transfer RNAs (pre-tRNAs) require extensive processing to generate mature tRNAs possessing proper fold, structural stability, and functionality required to sustain cellular viability. The road to tRNA maturation follows an ordered process: 5'-processing, 3'-processing, modifications at specific sites, if any, and 3'-CCA addition before aminoacylation and recruitment to the cellular protein synthesis machinery. Ribonuclease P (RNase P) is a universally conserved endonuclease in all domains of life, performing the hydrolysis of pre-tRNA sequences at the 5' end by the removal of phosphodiester linkages between nucleotides at position -1 and +1. Except for an archaeal species: Nanoarchaeum equitans where tRNAs are transcribed from leaderless-position +1, RNase P is indispensable for life and displays fundamental variations in terms of enzyme subunit composition, mechanism of substrate recognition and active site architecture, utilizing in all cases a two metal ion-mediated conserved catalytic reaction. While the canonical RNA-based ribonucleoprotein RNase P has been well-known to occur in bacteria, archaea, and eukaryotes, the occurrence of RNA-free protein-only RNase P in eukaryotes and RNA-free homologs of Aquifex RNase P in prokaryotes has been discovered more recently. This review aims to provide a comprehensive overview of structural diversity displayed by various RNA-based and RNA-free RNase P holoenzymes towards harnessing critical RNA-protein and protein-protein interactions in achieving conserved pre-tRNA processing functionality. Furthermore, alternate roles and functional interchangeability of RNase P are discussed in the context of its employability in several clinical and biotechnological applications. This article is categorized under: RNA Processing > tRNA Processing RNA Evolution and Genomics > RNA and Ribonucleoprotein Evolution RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.
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Affiliation(s)
- Sagar Sridhara
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
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2
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Mohanty BK, Agrawal A, Kushner SR. Generation of pre-tRNAs from polycistronic operons is the essential function of RNase P in Escherichia coli. Nucleic Acids Res 2020; 48:2564-2578. [PMID: 31993626 PMCID: PMC7049720 DOI: 10.1093/nar/gkz1188] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 12/05/2019] [Accepted: 01/27/2020] [Indexed: 11/14/2022] Open
Abstract
Ribonuclease P (RNase P) is essential for the 5′-end maturation of tRNAs in all kingdoms of life. In Escherichia coli, temperature sensitive mutations in either its protein (rnpA49) and or RNA (rnpB709) subunits lead to inviability at nonpermissive temperatures. Using the rnpA49 temperature sensitive allele, which encodes a partially defective RNase P at the permissive temperature, we show here for the first time that the processing of RNase P-dependent polycistronic tRNA operons to release pre-tRNAs is the essential function of the enzyme, since the majority of 5′-immature tRNAs can be aminoacylated unless their 5′-extensions ≥8 nt. Surprisingly, the failure of 5′-end maturation elicits increased polyadenylation of some pre-tRNAs by poly(A) polymerase I (PAP I), which exacerbates inviability. The absence of PAP I led to improved aminoacylation of 5′-immature tRNAs. Our data suggest a more dynamic role for PAP I in maintaining functional tRNA levels in the cell.
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Affiliation(s)
- Bijoy K Mohanty
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Ankit Agrawal
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Sidney R Kushner
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
- To whom correspondence should be addressed. Tel: +706 542 1440; Fax: +706 542 1439;
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3
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Transcription, Processing, and Decay of Mitochondrial RNA in Health and Disease. Int J Mol Sci 2019; 20:ijms20092221. [PMID: 31064115 PMCID: PMC6540609 DOI: 10.3390/ijms20092221] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 05/01/2019] [Accepted: 05/03/2019] [Indexed: 12/16/2022] Open
Abstract
Although the large majority of mitochondrial proteins are nuclear encoded, for their correct functioning mitochondria require the expression of 13 proteins, two rRNA, and 22 tRNA codified by mitochondrial DNA (mtDNA). Once transcribed, mitochondrial RNA (mtRNA) is processed, mito-ribosomes are assembled, and mtDNA-encoded proteins belonging to the respiratory chain are synthesized. These processes require the coordinated spatio-temporal action of several enzymes, and many different factors are involved in the regulation and control of protein synthesis and in the stability and turnover of mitochondrial RNA. In this review, we describe the essential steps of mitochondrial RNA synthesis, maturation, and degradation, the factors controlling these processes, and how the alteration of these processes is associated with human pathologies.
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4
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Ferreira N, Rackham O, Filipovska A. Regulation of a minimal transcriptome by repeat domain proteins. Semin Cell Dev Biol 2018; 76:132-141. [DOI: 10.1016/j.semcdb.2017.08.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/15/2017] [Accepted: 08/18/2017] [Indexed: 01/19/2023]
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5
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Kayal E, Bentlage B, Collins AG. Insights into the transcriptional and translational mechanisms of linear organellar chromosomes in the box jellyfish Alatina alata (Cnidaria: Medusozoa: Cubozoa). RNA Biol 2016; 13:799-809. [PMID: 27267414 DOI: 10.1080/15476286.2016.1194161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND In most animals, the mitochondrial genome is characterized by its small size, organization into a single circular molecule, and a relative conservation of the number of encoded genes. In box jellyfish (Cubozoa, Cnidaria), the mitochondrial genome is organized into 8 linear mito-chromosomes harboring between one and 4 genes each, including 2 extra protein-coding genes: mt-polB and orf314. Such an organization challenges the traditional view of mitochondrial DNA (mtDNA) expression in animals. In this study, we investigate the pattern of mitochondrial gene expression in the box jellyfish Alatina alata, as well as several key nuclear-encoded molecular pathways involved in the processing of mitochondrial gene transcription. RESULTS Read coverage of DNA-seq data is relatively uniform for all 8 mito-chromosomes, suggesting that each mito-chromosome is present in equimolar proportion in the mitochondrion. Comparison of DNA and RNA-seq based assemblies indicates that mito-chromosomes are transcribed into individual transcripts in which the beginning and ending are highly conserved. Expression levels for mt-polB and orf314 are similar to those of other mitochondrial-encoded genes, which provides further evidence for them having functional roles in the mitochondrion. Survey of the transcriptome suggests recognition of the mitochondrial tRNA-Met by the cytoplasmic aminoacyl-tRNA synthetase counterpart and C-to-U editing of the cytoplasmic tRNA-Trp after import into the mitochondrion. Moreover, several mitochondrial ribosomal proteins appear to be lost. CONCLUSIONS This study represents the first survey of mitochondrial gene expression of the linear multi-chromosomal mtDNA in box jellyfish (Cubozoa). Future exploration of small RNAs and the proteome of the mitochondrion will test the hypotheses presented herein.
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Affiliation(s)
- Ehsan Kayal
- a Department of Invertebrate Zoology , National Museum of Natural History, Smithsonian Institution , Washington DC , USA
| | - Bastian Bentlage
- a Department of Invertebrate Zoology , National Museum of Natural History, Smithsonian Institution , Washington DC , USA
| | - Allen G Collins
- a Department of Invertebrate Zoology , National Museum of Natural History, Smithsonian Institution , Washington DC , USA.,b National Systematics Laboratory of NOAA's Fisheries Service, National Museum of Natural History , Washington , DC , USA
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6
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Systematically frameshifting by deletion of every 4th or 4th and 5th nucleotides during mitochondrial transcription: RNA self-hybridization regulates delRNA expression. Biosystems 2016; 142-143:43-51. [PMID: 27018206 DOI: 10.1016/j.biosystems.2016.03.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 03/11/2016] [Accepted: 03/23/2016] [Indexed: 02/05/2023]
Abstract
In mitochondria, secondary structures punctuate post-transcriptional RNA processing. Recently described transcripts match the human mitogenome after systematic deletions of every 4th, respectively every 4th and 5th nucleotides, called delRNAs. Here I explore predicted stem-loop hairpin formation by delRNAs, and their associations with delRNA transcription and detected peptides matching their translation. Despite missing 25, respectively 40% of the nucleotides in the original sequence, del-transformed sequences form significantly more secondary structures than corresponding randomly shuffled sequences, indicating biological function, independently of, and in combination with, previously detected delRNA and thereof translated peptides. Self-hybridization decreases delRNA abundances, indicating downregulation. Systematic deletions of the human mitogenome reveal new, unsuspected coding and structural informations.
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7
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Amberger A, Deutschmann AJ, Traunfellner P, Moser P, Feichtinger RG, Kofler B, Zschocke J. 17β-Hydroxysteroid dehydrogenase type 10 predicts survival of patients with colorectal cancer and affects mitochondrial DNA content. Cancer Lett 2016; 374:149-155. [PMID: 26884257 DOI: 10.1016/j.canlet.2016.02.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 02/04/2023]
Abstract
Mitochondrial energy production is reduced in tumor cells, and altered mitochondrial respiration contributes to tumor progression. Synthesis of proteins coded by mitochondrial DNA (mtDNA) requires the correct processing of long polycistronic precursor RNA molecules. Mitochondrial RNase P, composed of three different proteins (MRPP1, HSD10, and MRPP3), is necessary for correct RNA processing. Here we analyzed the role of RNase P proteins in colorectal cancer. High HSD10 expression was found in 28%; high MRPP1 expression in 40% of colorectal cancers, respectively. Expression of both proteins was not significantly associated with clinicopathological parameters. Survival analysis revealed that loss of HSD10 expression is associated with poor prognosis. Cox regression demonstrated that patients with high HSD10 tumors are at lower risk. High HSD10 expression was significantly associated with high mtDNA content in tumor tissue. A causal effect of HSD10 overexpression or knock down with increased or reduced mtDNA levels, respectively, was confirmed in tumor cell lines. Our data suggest that HSD10 plays a role in alterations of energy metabolism by regulating mtDNA content in colorectal carcinomas, and HSD10 protein analysis may be of prognostic value.
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Affiliation(s)
- Albert Amberger
- Division of Human Genetics, Medical University Innsbruck, Peter Mayr Straße 1, 6020 Innsbruck, Austria.
| | - Andrea J Deutschmann
- Division of Human Genetics, Medical University Innsbruck, Peter Mayr Straße 1, 6020 Innsbruck, Austria
| | - Pia Traunfellner
- Division of Human Genetics, Medical University Innsbruck, Peter Mayr Straße 1, 6020 Innsbruck, Austria
| | - Patrizia Moser
- Institute of General Pathology, Medical University Innsbruck, Müllerstraße 44, 6020 Innsbruck, Austria
| | - René G Feichtinger
- Laura-Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University Salzburg, Müllner Hauptstraße 48, 5020 Salzburg, Austria
| | - Barbara Kofler
- Laura-Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University Salzburg, Müllner Hauptstraße 48, 5020 Salzburg, Austria
| | - Johannes Zschocke
- Division of Human Genetics, Medical University Innsbruck, Peter Mayr Straße 1, 6020 Innsbruck, Austria.
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8
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Van Haute L, Pearce SF, Powell CA, D’Souza AR, Nicholls TJ, Minczuk M. Mitochondrial transcript maturation and its disorders. J Inherit Metab Dis 2015; 38:655-80. [PMID: 26016801 PMCID: PMC4493943 DOI: 10.1007/s10545-015-9859-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 04/27/2015] [Accepted: 04/29/2015] [Indexed: 11/03/2022]
Abstract
Mitochondrial respiratory chain deficiencies exhibit a wide spectrum of clinical presentations owing to defective mitochondrial energy production through oxidative phosphorylation. These defects can be caused by either mutations in the mitochondrial DNA (mtDNA) or mutations in nuclear genes coding for mitochondrially-targeted proteins. The underlying pathomechanisms can affect numerous pathways involved in mitochondrial biology including expression of mtDNA-encoded genes. Expression of the mitochondrial genes is extensively regulated at the post-transcriptional stage and entails nucleolytic cleavage of precursor RNAs, RNA nucleotide modifications, RNA polyadenylation, RNA quality and stability control. These processes ensure proper mitochondrial RNA (mtRNA) function, and are regulated by dedicated, nuclear-encoded enzymes. Recent growing evidence suggests that mutations in these nuclear genes, leading to incorrect maturation of RNAs, are a cause of human mitochondrial disease. Additionally, mutations in mtDNA-encoded genes may also affect RNA maturation and are frequently associated with human disease. We review the current knowledge on a subset of nuclear-encoded genes coding for proteins involved in mitochondrial RNA maturation, for which genetic variants impacting upon mitochondrial pathophysiology have been reported. Also, primary pathological mtDNA mutations with recognised effects upon RNA processing are described.
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Affiliation(s)
| | - Sarah F. Pearce
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 0XY UK
| | | | - Aaron R. D’Souza
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 0XY UK
| | - Thomas J. Nicholls
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 0XY UK
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 0XY UK
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9
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Vilardo E, Rossmanith W. Molecular insights into HSD10 disease: impact of SDR5C1 mutations on the human mitochondrial RNase P complex. Nucleic Acids Res 2015; 43:5112-9. [PMID: 25925575 PMCID: PMC4446446 DOI: 10.1093/nar/gkv408] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 04/16/2015] [Indexed: 11/25/2022] Open
Abstract
SDR5C1 is an amino and fatty acid dehydrogenase/reductase, moonlighting as a component of human mitochondrial RNase P, which is the enzyme removing 5′-extensions of tRNAs, an early and crucial step in tRNA maturation. Moreover, a subcomplex of mitochondrial RNase P catalyzes the N1-methylation of purines at position 9, a modification found in most mitochondrial tRNAs and thought to stabilize their structure. Missense mutations in SDR5C1 cause a disease characterized by progressive neurodegeneration and cardiomyopathy, called HSD10 disease. We have investigated the effect of selected mutations on SDR5C1's functions. We show that pathogenic mutations impair SDR5C1-dependent dehydrogenation, tRNA processing and methylation. Some mutations disrupt the homotetramerization of SDR5C1 and/or impair its interaction with TRMT10C, the methyltransferase subunit of the mitochondrial RNase P complex. We propose that the structural and functional alterations of SDR5C1 impair mitochondrial RNA processing and modification, leading to the mitochondrial dysfunction observed in HSD10 patients.
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Affiliation(s)
- Elisa Vilardo
- Center for Anatomy & Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
| | - Walter Rossmanith
- Center for Anatomy & Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
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10
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Pinker F, Bonnard G, Gobert A, Gutmann B, Hammani K, Sauter C, Gegenheimer PA, Giegé P. PPR proteins shed a new light on RNase P biology. RNA Biol 2013; 10:1457-68. [PMID: 23925311 PMCID: PMC3858429 DOI: 10.4161/rna.25273] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A fast growing number of studies identify pentatricopeptide repeat (PPR) proteins as major players in gene expression processes. Among them, a subset of PPR proteins called PRORP possesses RNase P activity in several eukaryotes, both in nuclei and organelles. RNase P is the endonucleolytic activity that removes 5′ leader sequences from tRNA precursors and is thus essential for translation. Before the characterization of PRORP, RNase P enzymes were thought to occur universally as ribonucleoproteins, although some evidence implied that some eukaryotes or cellular compartments did not use RNA for RNase P activity. The characterization of PRORP reveals a two-domain enzyme, with an N-terminal domain containing multiple PPR motifs and assumed to achieve target specificity and a C-terminal domain holding catalytic activity. The nature of PRORP interactions with tRNAs suggests that ribonucleoprotein and protein-only RNase P enzymes share a similar substrate binding process.
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Affiliation(s)
- Franziska Pinker
- Institut de Biologie Moléculaire des Plantes du CNRS; Université de Strasbourg; Strasbourg, France; Institut de Biologie Moléculaire et Cellulaire du CNRS; Architecture et Réactivité de l'ARN; Université de Strasbourg; Strasbourg, France
| | - Géraldine Bonnard
- Institut de Biologie Moléculaire des Plantes du CNRS; Université de Strasbourg; Strasbourg, France
| | - Anthony Gobert
- Institut de Biologie Moléculaire des Plantes du CNRS; Université de Strasbourg; Strasbourg, France
| | - Bernard Gutmann
- Institut de Biologie Moléculaire des Plantes du CNRS; Université de Strasbourg; Strasbourg, France
| | - Kamel Hammani
- Institut de Biologie Moléculaire des Plantes du CNRS; Université de Strasbourg; Strasbourg, France
| | - Claude Sauter
- Institut de Biologie Moléculaire et Cellulaire du CNRS; Architecture et Réactivité de l'ARN; Université de Strasbourg; Strasbourg, France
| | | | - Philippe Giegé
- Institut de Biologie Moléculaire des Plantes du CNRS; Université de Strasbourg; Strasbourg, France
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11
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Vilardo E, Nachbagauer C, Buzet A, Taschner A, Holzmann J, Rossmanith W. A subcomplex of human mitochondrial RNase P is a bifunctional methyltransferase--extensive moonlighting in mitochondrial tRNA biogenesis. Nucleic Acids Res 2012; 40:11583-93. [PMID: 23042678 PMCID: PMC3526285 DOI: 10.1093/nar/gks910] [Citation(s) in RCA: 177] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Transfer RNAs (tRNAs) reach their mature functional form through several steps of processing and modification. Some nucleotide modifications affect the proper folding of tRNAs, and they are crucial in case of the non-canonically structured animal mitochondrial tRNAs, as exemplified by the apparently ubiquitous methylation of purines at position 9. Here, we show that a subcomplex of human mitochondrial RNase P, the endonuclease removing tRNA 5′ extensions, is the methyltransferase responsible for m1G9 and m1A9 formation. The ability of the mitochondrial tRNA:m1R9 methyltransferase to modify both purines is uncommon among nucleic acid modification enzymes. In contrast to all the related methyltransferases, the human mitochondrial enzyme, moreover, requires a short-chain dehydrogenase as a partner protein. Human mitochondrial RNase P, thus, constitutes a multifunctional complex, whose subunits moonlight in cascade: a fatty and amino acid degradation enzyme in tRNA methylation and the methyltransferase, in turn, in tRNA 5′ end processing.
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Affiliation(s)
- Elisa Vilardo
- Center for Anatomy and Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
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12
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Rackham O, Mercer TR, Filipovska A. The human mitochondrial transcriptome and the RNA-binding proteins that regulate its expression. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 3:675-95. [DOI: 10.1002/wrna.1128] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Rossmanith W. Of P and Z: mitochondrial tRNA processing enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1819:1017-26. [PMID: 22137969 PMCID: PMC3790967 DOI: 10.1016/j.bbagrm.2011.11.003] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 11/11/2011] [Accepted: 11/15/2011] [Indexed: 12/18/2022]
Abstract
Mitochondrial tRNAs are generally synthesized as part of polycistronic transcripts. Release of tRNAs from these precursors is thus not only required to produce functional adaptors for translation, but also responsible for the maturation of other mitochondrial RNA species. Cleavage of mitochondrial tRNAs appears to be exclusively accomplished by endonucleases. 5'-end maturation in the mitochondria of different Eukarya is achieved by various kinds of RNase P, representing the full range of diversity found in this enzyme family. While ribonucleoprotein enzymes with RNA components of bacterial-like appearance are found in a few unrelated protists, algae, and fungi, highly degenerate RNAs of dramatic size variability are found in the mitochondria of many fungi. The majority of mitochondrial RNase P enzymes, however, appear to be pure protein enzymes. Human mitochondrial RNase P, the first to be identified and possibly the prototype of all animal mitochondrial RNases P, is composed of three proteins. Homologs of its nuclease subunit MRPP3/PRORP, are also found in plants, algae and several protists, where they are apparently responsible for RNase P activity in mitochondria (and beyond) without the help of extra subunits. The diversity of RNase P enzymes is contrasted by the uniformity of mitochondrial RNases Z, which are responsible for 3'-end processing. Only the long form of RNase Z, which is restricted to eukarya, is found in mitochondria, even when an additional short form is present in the same organism. Mitochondrial tRNA processing thus appears dominated by new, eukaryal inventions rather than bacterial heritage. This article is part of a Special Issue entitled: Mitochondrial Gene Expression.
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Affiliation(s)
- Walter Rossmanith
- Center for Anatomy & Cell Biology, Medical University of Vienna, Austria.
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14
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Rackham O, Filipovska A. The role of mammalian PPR domain proteins in the regulation of mitochondrial gene expression. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1819:1008-16. [PMID: 22051507 DOI: 10.1016/j.bbagrm.2011.10.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 10/14/2011] [Accepted: 10/17/2011] [Indexed: 12/26/2022]
Abstract
Pentatricopeptide repeat (PPR) domain proteins are a large family of RNA-binding proteins that are involved in the maturation and translation of organelle transcripts in eukaryotes. They were first identified in plant organelles and their important role in mammalian mitochondrial gene regulation is now emerging. Mammalian PPR proteins, like their plant counterparts, have diverse roles in mitochondrial transcription, RNA metabolism and translation and consequently are important for mitochondrial function and cell health. Here we discuss the current knowledge about the seven mammalian PPR proteins identified to date and their roles in the regulation of mitochondrial gene expression. Furthermore we discuss the mitochondrial RNA targets of the mammalian PPR proteins and methods to investigate the RNA targets of these mitochondrial RNA-binding proteins. This article is part of a Special Issue entitled: Mitochondrial Gene Expression.
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Affiliation(s)
- Oliver Rackham
- Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA 6000, Australia
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15
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Czerwoniec A, Bujnicki JM. Identification and modeling of a phosphatase-like domain in a tRNA 2'-O-ribosyl phosphate transferase Rit1p. Cell Cycle 2011; 10:3566-70. [PMID: 22030622 DOI: 10.4161/cc.10.20.17857] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cytoplasmic initiator tRNAs from plants and fungi are excluded from participating in translational elongation by the presence of a unique 2'-phosphoribosyl modification of purine 64, introduced posttranscriptionally by the enzyme Rit1p. Members of the Rit1p family show no obvious similarity to other proteins or domains, there is no structural information available to guide experimental analyses, and the mechanism of action of this enzyme remains a mystery. Using protein fold recognition, we identified a phosphatase-like domain in the C-terminal part of Rit1p. A comparative model of the C-terminal domain was constructed and used to predict the function of conserved residues and to propose the mechanism of action of Rit1p. The model will facilitate experimental analyses of Rit1p and its interactions with the initiator tRNA substrate.
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Affiliation(s)
- Anna Czerwoniec
- Bioinformatics Laboratory, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland.
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16
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Mercer TR, Neph S, Dinger ME, Crawford J, Smith MA, Shearwood AMJ, Haugen E, Bracken CP, Rackham O, Stamatoyannopoulos JA, Filipovska A, Mattick JS. The human mitochondrial transcriptome. Cell 2011; 146:645-58. [PMID: 21854988 DOI: 10.1016/j.cell.2011.06.051] [Citation(s) in RCA: 590] [Impact Index Per Article: 45.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 06/15/2011] [Accepted: 06/27/2011] [Indexed: 11/27/2022]
Abstract
The human mitochondrial genome comprises a distinct genetic system transcribed as precursor polycistronic transcripts that are subsequently cleaved to generate individual mRNAs, tRNAs, and rRNAs. Here, we provide a comprehensive analysis of the human mitochondrial transcriptome across multiple cell lines and tissues. Using directional deep sequencing and parallel analysis of RNA ends, we demonstrate wide variation in mitochondrial transcript abundance and precisely resolve transcript processing and maturation events. We identify previously undescribed transcripts, including small RNAs, and observe the enrichment of several nuclear RNAs in mitochondria. Using high-throughput in vivo DNaseI footprinting, we establish the global profile of DNA-binding protein occupancy across the mitochondrial genome at single-nucleotide resolution, revealing regulatory features at mitochondrial transcription initiation sites and functional insights into disease-associated variants. This integrated analysis of the mitochondrial transcriptome reveals unexpected complexity in the regulation, expression, and processing of mitochondrial RNA and provides a resource for future studies of mitochondrial function (accessed at http://mitochondria.matticklab.com).
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Affiliation(s)
- Tim R Mercer
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
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17
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Localization of human RNase Z isoforms: dual nuclear/mitochondrial targeting of the ELAC2 gene product by alternative translation initiation. PLoS One 2011; 6:e19152. [PMID: 21559454 PMCID: PMC3084753 DOI: 10.1371/journal.pone.0019152] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 03/18/2011] [Indexed: 11/19/2022] Open
Abstract
RNase Z is an endonuclease responsible for the removal of 3' extensions from tRNA precursors, an essential step in tRNA biogenesis. Human cells contain a long form (RNase Z(L)) encoded by ELAC2, and a short form (RNase Z(S); ELAC1). We studied their subcellular localization by expression of proteins fused to green fluorescent protein. RNase Z(S) was found in the cytosol, whereas RNase Z(L) localized to the nucleus and mitochondria. We show that alternative translation initiation is responsible for the dual targeting of RNase Z(L). Due to the unfavorable context of the first AUG of ELAC2, translation apparently also starts from the second AUG, whereby the mitochondrial targeting sequence is lost and the protein is instead routed to the nucleus. Our data suggest that RNase Z(L) is the enzyme involved in both, nuclear and mitochondrial tRNA 3' end maturation.
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Gobert A, Gutmann B, Taschner A, Gössringer M, Holzmann J, Hartmann RK, Rossmanith W, Giegé P. A single Arabidopsis organellar protein has RNase P activity. Nat Struct Mol Biol 2010; 17:740-4. [PMID: 20473316 DOI: 10.1038/nsmb.1812] [Citation(s) in RCA: 174] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Accepted: 03/19/2010] [Indexed: 12/18/2022]
Abstract
The ubiquitous endonuclease RNase P is responsible for the 5' maturation of tRNA precursors. Until the discovery of human mitochondrial RNase P, these enzymes had typically been found to be ribonucleoproteins, the catalytic activity of which is associated with the RNA component. Here we show that, in Arabidopsis thaliana mitochondria and plastids, a single protein called 'proteinaceous RNase P' (PRORP1) can perform the endonucleolytic maturation of tRNA precursors that defines RNase P activity. In addition, PRORP1 is able to cleave tRNA-like structures involved in the maturation of plant mitochondrial mRNAs. Finally, we show that Arabidopsis PRORP1 can replace the bacterial ribonucleoprotein RNase P in Escherichia coli cells. PRORP2 and PRORP3, two paralogs of PRORP1, are both localized in the nucleus.
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Affiliation(s)
- Anthony Gobert
- Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, Strasbourg, France
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