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Singh Y, Bird JG. A gel electrophoresis-based assay for measuring enzymatic RNA decapping activity. Methods Enzymol 2022; 675:323-350. [DOI: 10.1016/bs.mie.2022.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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2
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Bird JG, Basu U, Kuster D, Ramachandran A, Grudzien-Nogalska E, Towheed A, Wallace DC, Kiledjian M, Temiakov D, Patel SS, Ebright RH, Nickels BE. Highly efficient 5' capping of mitochondrial RNA with NAD + and NADH by yeast and human mitochondrial RNA polymerase. eLife 2018; 7:42179. [PMID: 30526856 PMCID: PMC6298784 DOI: 10.7554/elife.42179] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/10/2018] [Indexed: 12/16/2022] Open
Abstract
Bacterial and eukaryotic nuclear RNA polymerases (RNAPs) cap RNA with the oxidized and reduced forms of the metabolic effector nicotinamide adenine dinucleotide, NAD+ and NADH, using NAD+ and NADH as non-canonical initiating nucleotides for transcription initiation. Here, we show that mitochondrial RNAPs (mtRNAPs) cap RNA with NAD+ and NADH, and do so more efficiently than nuclear RNAPs. Direct quantitation of NAD+- and NADH-capped RNA demonstrates remarkably high levels of capping in vivo: up to ~60% NAD+ and NADH capping of yeast mitochondrial transcripts, and up to ~15% NAD+ capping of human mitochondrial transcripts. The capping efficiency is determined by promoter sequence at, and upstream of, the transcription start site and, in yeast and human cells, by intracellular NAD+ and NADH levels. Our findings indicate mtRNAPs serve as both sensors and actuators in coupling cellular metabolism to mitochondrial transcriptional outputs, sensing NAD+ and NADH levels and adjusting transcriptional outputs accordingly.
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Affiliation(s)
- Jeremy G Bird
- Department of Genetics and Waksman Institute, Rutgers University, United States.,Department of Chemistry and Waksman Institute, Rutgers University, United States
| | - Urmimala Basu
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, United States.,Biochemistry PhD Program, School of Graduate Studies, Rutgers University, United States
| | - David Kuster
- Department of Genetics and Waksman Institute, Rutgers University, United States.,Department of Chemistry and Waksman Institute, Rutgers University, United States.,Biochemistry Center Heidelberg, Heidelberg University, Germany
| | - Aparna Ramachandran
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, United States
| | | | - Atif Towheed
- Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, United States
| | - Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, United States.,Department of Pediatrics, Division of Human Genetics, The Children's Hospital of Philadelphia, Perelman School of Medicine, United States
| | | | - Dmitry Temiakov
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, United States
| | - Smita S Patel
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, United States
| | - Richard H Ebright
- Department of Chemistry and Waksman Institute, Rutgers University, United States
| | - Bryce E Nickels
- Department of Genetics and Waksman Institute, Rutgers University, United States
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3
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Analysis of RNA 5' ends: Phosphate enumeration and cap characterization. Methods 2018; 155:3-9. [PMID: 30419334 DOI: 10.1016/j.ymeth.2018.10.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/24/2018] [Accepted: 10/30/2018] [Indexed: 12/21/2022] Open
Abstract
The function and fate of cellular RNAs are often governed by the phosphorylation state at the 5' end or the identity of whatever cap may be present there. Here we describe methods for examining these important 5'-terminal features on any cellular or synthetic RNA of interest that can be detected by Northern blotting. One such method, PABLO, is a splinted ligation assay that makes it possible to accurately quantify the percentage of 5' ends that are monophosphorylated. Another, PACO, is a capping assay that reveals the percentage of 5' ends that are diphosphorylated. A third, boronate gel electrophoresis in conjunction with deoxyribozyme-mediated cleavage, enables different types of caps (e.g., m7Gppp caps versus NAD caps) to be distinguished from one another and the percentage of each to be determined. After completing all three tests, the percentage of 5' ends that are triphosphorylated can be deduced by process of elimination. Together, this battery of assays allows the 5' terminus of an RNA to be profiled in unprecedented detail.
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Matts JA, Sytnikova Y, Chirn GW, Igloi GL, Lau NC. Small RNA library construction from minute biological samples. Methods Mol Biol 2014; 1093:123-36. [PMID: 24178561 DOI: 10.1007/978-1-62703-694-8_10] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Increasingly, the discovery and characterization of small regulatory RNAs from a variety of organisms have all required deep-sequencing methodologies. However, the crux to successful deep-sequencing analysis depends upon optimal construction of a cDNA library compatible for the high-throughput sequencing platform. Challenges to small RNA library constructions arise when dealing with minute tissue samples because certain structural RNA fragments can dominate and mask the desired characterization of regulatory small RNAs like microRNAs (miRNAs), endogenous small interfering RNAs (endo-siRNAs), and Piwi-interacting RNAs (piRNAs). Here, we describe methods that improve the chances of constructing a successful library from small RNAs isolated from minute tissues such as enriched follicle cells from the Drosophila ovarium. Because the ribosomal RNA (rRNA) fragments are frequently the major contaminants in small RNA preparations from minute amounts of tissue, we demonstrate the utility of antisense oligonucleotide depletion and an acryloylaminophenylboronic acid (APB) polyacrylamide gel system for separating the abundant 2S rRNA in Drosophila from endo-siRNAs and piRNAs. Finally, our methodology generates libraries amenable to multiplex sequencing on the Illumina Hi-Seq platform.
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Affiliation(s)
- Jessica A Matts
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, USA
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Cristodero M, Seebeck T, Schneider A. Mitochondrial translation is essential in bloodstream forms of Trypanosoma brucei. Mol Microbiol 2010; 78:757-69. [PMID: 20969649 DOI: 10.1111/j.1365-2958.2010.07368.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The parasitic protozoa Trypanosoma brucei has a complex life cycle. Oxidative phosphorylation is highly active in the procyclic form but absent from bloodstream cells. The mitochondrial genome encodes several gene products that are required for oxidative phosphorylation, but it completely lacks tRNA genes. For mitochondrial translation to occur, the import of cytosolic tRNAs is therefore essential for procyclic T. brucei. Whether the same is true for the bloodstream form has not been studied so far. Here we show that the steady-state levels of mitochondrial tRNAs are essentially the same in both life stages. Editing of the imported tRNA(Trp) also occurs in both forms as well as in mitochondria of Trypanosoma evansi, which lacks a genome and a translation system. These results show that mitochondrial tRNA import is a constitutive process that must be mediated by proteins that are expressed in both forms of the life cycle and that are not encoded in the mitochondrial genome. Moreover, bloodstream cells lacking either mitochondria-specific translation elongation factor Tu or mitochondrial tryptophanyl-tRNA synthetase are not viable indicating that mitochondrial translation is also essential in this stage. Both of these proteins show trypanosomatid-specific features and may therefore be excellent novel drug targets.
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Affiliation(s)
- Marina Cristodero
- Department of Chemistry and Biochemistry, University of Bern, Freiestr. 3, CH-3012 Bern, Switzerland
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Bruske EI, Sendfeld F, Schneider A. Thiolated tRNAs of Trypanosoma brucei are imported into mitochondria and dethiolated after import. J Biol Chem 2009; 284:36491-36499. [PMID: 19875444 DOI: 10.1074/jbc.m109.064527] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
All mitochondrial tRNAs in Trypanosoma brucei derive from cytosolic tRNAs that are in part imported into mitochondria. Some trypanosomal tRNAs are thiolated in a compartment-specific manner. We have identified three proteins required for the thio modification of cytosolic tRNA(Gln), tRNA(Glu), and tRNA(Lys). RNA interference-mediated ablation of these proteins results in the cytosolic accumulation non-thio-modified tRNAs but does not increase their import. Moreover, in vitro import experiments showed that both thio-modified and non-thio-modified tRNA(Glu) can efficiently be imported into mitochondria. These results indicate that unlike previously suggested the cytosol-specific thio modifications do not function as antideterminants for mitochondrial tRNA import. Consistent with these results we showed by using inducible expression of a tagged tRNA(Glu) that it is mainly the thiolated form that is imported in vivo. Unexpectedly, the imported tRNA becomes dethiolated after import, which explains why the non-thiolated form is enriched in mitochondria. Finally, we have identified two genes required for thiolation of imported tRNA(Trp) whose wobble nucleotide is subject to mitochondrial C to U editing. Interestingly, down-regulation of thiolation resulted in an increase of edited tRNA(Trp) but did not affect growth.
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Affiliation(s)
- Ellen Inga Bruske
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Franziska Sendfeld
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - André Schneider
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
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Förster C, Chakraburtty K, Sprinzl M. Discrimination between initiation and elongation of protein biosynthesis in yeast: identity assured by a nucleotide modification in the initiator tRNA. Nucleic Acids Res 1993; 21:5679-83. [PMID: 8284215 PMCID: PMC310535 DOI: 10.1093/nar/21.24.5679] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cytoplasmic initiator tRNAs from plants and fungi possess an unique 2'-phosphoribosyl residue at position 64 of their sequence. In yeast tRNA(iMet), this modified nucleotide located in the T-stem of the tRNA is a 2'-1''-(beta-O-ribofuranosyl-5''-phosphoryl)-adenosine. The phosphoribosyl residue of this modified nucleoside was removed chemically by treatment involving periodate oxidation of tRNA(iMet) and regeneration of the 3'-terminal adenosine with ATP (CTP):tRNA nucleotidyl transferase. The role of phosphoribosylation at position 64 for interaction with elongation factor eEF-1 alpha and initiation factor 2 (eIF-2) was investigated in the homologous yeast system. Whereas the 5'-phosphoribosyl residue prevents the binding of Met-tRNA(iMet) to eEF-1 alpha, it does not influence the interaction with eIF-2. After removal of the ribosyl group, the demodified initiator tRNA showed binding to eEF-1 alpha, but no change was detected with respect to the interaction with the initiation factor eIF-2. This observation is interpreted to mean that a single modification of an eucaryotic initiator tRNA in yeast serves as a negative discriminant for eEF-1 alpha, thus preventing the initiator tRNA(iMet) from entering the elongation cycle of protein biosynthesis.
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Affiliation(s)
- C Förster
- Laboratorium für Biochemie, Universität Bayreuth, Germany
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Görlach M, Hermann M, Schwemmle M, Hilse K. Binding of globin mRNA, beta-globin mRNA segments and RNA homopolymers by immobilized protein of polysomal globin messenger ribonucleoprotein. EUROPEAN JOURNAL OF BIOCHEMISTRY 1989; 184:589-96. [PMID: 2806242 DOI: 10.1111/j.1432-1033.1989.tb15054.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The binding of rabbit globin mRNA, in-vitro-generated beta-globin mRNA segments, and RNA homopolymers by proteins of rabbit reticulocyte polysomal messenger ribonucleoproteins (mRNP) after SDS gel electrophoresis and electroblotting was examined. The polysomal mRNP proteins have a higher affinity for mRNA than for rRNA and tRNA while having a higher affinity for polypurine than polypyrimidine homopolymers. Binding experiments with synthetic poly(A) and with segments of beta-globin mRNA transcribed from a cDNA in vitro revealed a set of polysomal mRNP proteins which preferentially bind the poly(A)-free beta-globin mRNA. A protein of Mr 90,000 binds specifically the 3'-nontranslated trailer of the poly(A)-free beta-globin mRNA and not the poly(A)-containing globin mRNA. Another set of proteins preferentially binds poly(A). The latter group of proteins contains a prominent species of Mr 72,000, which is most likely the rabbit poly(A)-binding protein. Three polysomal mRNP proteins which bound rabbit globin mRNA did not bind preferentially any of the other RNA probes used.
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Affiliation(s)
- M Görlach
- Institut für Biologie III, Universität Freiburg, Federal Republic of Germany
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