1
|
Yared MJ, Marcelot A, Barraud P. Beyond the Anticodon: tRNA Core Modifications and Their Impact on Structure, Translation and Stress Adaptation. Genes (Basel) 2024; 15:374. [PMID: 38540433 PMCID: PMC10969862 DOI: 10.3390/genes15030374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 06/14/2024] Open
Abstract
Transfer RNAs (tRNAs) are heavily decorated with post-transcriptional chemical modifications. Approximately 100 different modifications have been identified in tRNAs, and each tRNA typically contains 5-15 modifications that are incorporated at specific sites along the tRNA sequence. These modifications may be classified into two groups according to their position in the three-dimensional tRNA structure, i.e., modifications in the tRNA core and modifications in the anticodon-loop (ACL) region. Since many modified nucleotides in the tRNA core are involved in the formation of tertiary interactions implicated in tRNA folding, these modifications are key to tRNA stability and resistance to RNA decay pathways. In comparison to the extensively studied ACL modifications, tRNA core modifications have generally received less attention, although they have been shown to play important roles beyond tRNA stability. Here, we review and place in perspective selected data on tRNA core modifications. We present their impact on tRNA structure and stability and report how these changes manifest themselves at the functional level in translation, fitness and stress adaptation.
Collapse
Affiliation(s)
| | | | - Pierre Barraud
- Expression Génétique Microbienne, Université Paris Cité, CNRS, Institut de Biologie Physico-Chimique, F-75005 Paris, France; (M.-J.Y.); (A.M.)
| |
Collapse
|
2
|
Maharjan S, Gamper H, Yamaki Y, Henley RY, Li NS, Suzuki T, Suzuki T, Piccirilli JA, Wanunu M, Seifert E, Wallace DC, Hou YM. Post-Transcriptional Methylation of Mitochondrial-tRNA Differentially Contributes to Mitochondrial Pathology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.09.569632. [PMID: 38106193 PMCID: PMC10723379 DOI: 10.1101/2023.12.09.569632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Human mitochondrial tRNAs (mt-tRNAs), critical for mitochondrial biogenesis, are frequently associated with pathogenic mutations. These mt-tRNAs have unusual sequence motifs and require post-transcriptional modifications to stabilize their fragile structures. However, whether a modification that stabilizes a wild-type (WT) mt-tRNA structure would also stabilize its pathogenic variants is unknown. Here we show that the N 1 -methylation of guanosine at position 9 (m 1 G9) of mt-Leu(UAA), while stabilizing the WT tRNA, has an opposite and destabilizing effect on variants associated with MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes). This differential effect is further demonstrated by the observation that demethylation of m 1 G9, while damaging to the WT tRNA, is beneficial to the major pathogenic variant, improving its structure and activity. These results have new therapeutic implications, suggesting that the N 1 -methylation of mt-tRNAs at position 9 is a determinant of pathogenicity and that controlling the methylation level is an important modulator of mt-tRNA-associated diseases.
Collapse
|
3
|
Biondi E, Benner SA. Artificially Expanded Genetic Information Systems for New Aptamer Technologies. Biomedicines 2018; 6:E53. [PMID: 29747381 PMCID: PMC6027400 DOI: 10.3390/biomedicines6020053] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/04/2018] [Accepted: 05/06/2018] [Indexed: 01/04/2023] Open
Abstract
Directed evolution was first applied to diverse libraries of DNA and RNA molecules a quarter century ago in the hope of gaining technology that would allow the creation of receptors, ligands, and catalysts on demand. Despite isolated successes, the outputs of this technology have been somewhat disappointing, perhaps because the four building blocks of standard DNA and RNA have too little functionality to have versatile binding properties, and offer too little information density to fold unambiguously. This review covers the recent literature that seeks to create an improved platform to support laboratory Darwinism, one based on an artificially expanded genetic information system (AEGIS) that adds independently replicating nucleotide “letters” to the evolving “alphabet”.
Collapse
Affiliation(s)
- Elisa Biondi
- Foundation for Applied Molecular Evolution, Alachua, FL 32615, USA.
- Firebird Biomolecular Sciences, LLC, Alachua, FL 32615, USA.
| | - Steven A Benner
- Foundation for Applied Molecular Evolution, Alachua, FL 32615, USA.
- Firebird Biomolecular Sciences, LLC, Alachua, FL 32615, USA.
| |
Collapse
|
4
|
Chao Z, Liuyang T, Nan L, Qi C, Zhongqi C, Yang L, Yuqi L. Mitochondrial tRNA mutation with high-salt stimulation on cardiac damage: underlying mechanism associated with change of Bax and VDAC. Am J Physiol Heart Circ Physiol 2016; 311:H1248-H1257. [PMID: 27638882 DOI: 10.1152/ajpheart.00874.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 07/21/2016] [Indexed: 12/31/2022]
Abstract
Mitochondrial transfer RNA (tRNA) mutation with high-salt stimulation can cause high blood pressure. However, the underlying mechanisms remain unclear. In the present study, we examined the potential molecular mechanisms of cardiac damage caused by mitochondrial tRNA mutation with high-salt stimulation in spontaneously hypertensive rats (SHR). Unanesthetized, 44-wk-old, male, SHR were divided into four groups: SHR, SHR with high-salt stimulation for 8 wk (SHR + NaCl), SHR carrying tRNA mutations (SHR + M), and SHR + M with high-salt stimulation for 8 wk (SHR + M + NaCl). Healthy Wistar-Kyoto (WKY) rats were used as controls. Left ventricular mass and interventricular septum were highest in the SHR + M + NaCl group ( P < 0.05), while ejection fraction was lowest in the SHR + M + NaCl group ( P < 0.05). Hematoxylin and eosin staining showed myocardial cell hypertrophy with interstitial fibrosis and localized inflammatory cell infiltration, in the hypertensive groups, particularly in the SHR + M + NaCl group. Electron microscopy showed different degrees of mitochondrial cavitation in heart tissue of the hypertensive groups, which was highest in the SHR + M + NaCl group. In hypertensive animals, levels of reactive oxygen species were highest in the SHR + M + NaCl group ( P < 0.05). Expression of the voltage-dependent anion channel (VDAC) and the apoptosis regulator Bax were highest in the SHR + M + NaCl group ( P < 0.05), which also showed evidence of VDAC and Bax colocalization ( P < 0.05). Overall, these data suggest that mitochondrial tRNA mutation with high-salt stimulation can aggravate cardiac damage, potentially because of increased expression and interaction between Bax and VDAC and increased reactive oxygen species formation and initiation of apoptosis.
Collapse
Affiliation(s)
- Zhu Chao
- Department of Cardiology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
| | - Tian Liuyang
- Medical College of Nan Kai University, Tianjing, China; and
| | - Li Nan
- Medical College of Nan Kai University, Tianjing, China; and
| | - Chen Qi
- Department of Cardiology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
| | - Cai Zhongqi
- Department of Cardiology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
| | - Li Yang
- Department of Cardiology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
- Institute of Geriatric Cardiology, and Chinese PLA General Hospital, Beijing, China
| | - Liu Yuqi
- Department of Cardiology, Chinese People's Liberation Army (PLA) General Hospital, Beijing, China
| |
Collapse
|
5
|
Duechler M, Leszczyńska G, Sochacka E, Nawrot B. Nucleoside modifications in the regulation of gene expression: focus on tRNA. Cell Mol Life Sci 2016; 73:3075-95. [PMID: 27094388 PMCID: PMC4951516 DOI: 10.1007/s00018-016-2217-y] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 03/25/2016] [Accepted: 04/04/2016] [Indexed: 01/10/2023]
Abstract
Both, DNA and RNA nucleoside modifications contribute to the complex multi-level regulation of gene expression. Modified bases in tRNAs modulate protein translation rates in a highly dynamic manner. Synonymous codons, which differ by the third nucleoside in the triplet but code for the same amino acid, may be utilized at different rates according to codon-anticodon affinity. Nucleoside modifications in the tRNA anticodon loop can favor the interaction with selected codons by stabilizing specific base pairs. Similarly, weakening of base pairing can discriminate against binding to near-cognate codons. mRNAs enriched in favored codons are translated in higher rates constituting a fine-tuning mechanism for protein synthesis. This so-called codon bias establishes a basic protein level, but sometimes it is necessary to further adjust the production rate of a particular protein to actual requirements, brought by, e.g., stages in circadian rhythms, cell cycle progression or exposure to stress. Such an adjustment is realized by the dynamic change of tRNA modifications resulting in the preferential translation of mRNAs coding for example for stress proteins to facilitate cell survival. Furthermore, tRNAs contribute in an entirely different way to another, less specific stress response consisting in modification-dependent tRNA cleavage that contributes to the general down-regulation of protein synthesis. In this review, we summarize control functions of nucleoside modifications in gene regulation with a focus on recent findings on protein synthesis control by tRNA base modifications.
Collapse
Affiliation(s)
- Markus Duechler
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363, Lodz, Poland.
| | - Grażyna Leszczyńska
- Institute of Organic Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924, Lodz, Poland
| | - Elzbieta Sochacka
- Institute of Organic Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924, Lodz, Poland
| | - Barbara Nawrot
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363, Lodz, Poland
| |
Collapse
|
6
|
Howard MJ, Karasik A, Klemm BP, Mei C, Shanmuganathan A, Fierke CA, Koutmos M. Differential substrate recognition by isozymes of plant protein-only Ribonuclease P. RNA (NEW YORK, N.Y.) 2016; 22:782-92. [PMID: 26966150 PMCID: PMC4836652 DOI: 10.1261/rna.055541.115] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 02/10/2016] [Indexed: 05/22/2023]
Abstract
Ribonuclease P (RNase P) catalyzes the cleavage of leader sequences from precursor tRNA (pre-tRNA). Typically, these enzymes are ribonucleic protein complexes that are found in all domains of life. However, a new class of RNase P has been discovered that is composed entirely of protein, termed protein-only RNase P (PRORP). To investigate the molecular determinants of PRORP substrate recognition, we measured the binding affinities and cleavage kinetics of Arabidopsis PRORP1 for varied pre-tRNA substrates. This analysis revealed that PRORP1 does not make significant contacts within the trailer or beyond N-1of the leader, indicating that this enzyme recognizes primarily the tRNA body. To determine the extent to which sequence variation within the tRNA body modulates substrate selectivity and to provide insight into the evolution and function of PRORP enzymes, we measured the reactivity of the three Arabidopsis PRORP isozymes (PRORP1-3) with four pre-tRNA substrates. A 13-fold range in catalytic efficiencies (10(4)-10(5)M(-1)s(-1)) was observed, demonstrating moderate selectivity for pre-tRNA substrates. Although PRORPs bind the different pre-tRNA species with affinities varying by as much as 100-fold, the three isozymes have similar affinities for a given pre-tRNA, suggesting similar binding modes. However, PRORP isozymes have varying degrees of cleavage fidelity, which is dependent on the pre-tRNA species and the presence of a 3'-discriminator base. This work defines molecular determinants of PRORP substrate recognition that provides insight into this new class of RNA processing enzymes.
Collapse
Affiliation(s)
- Michael J Howard
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Agnes Karasik
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA
| | - Bradley P Klemm
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Christine Mei
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Aranganathan Shanmuganathan
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA
| | - Carol A Fierke
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Markos Koutmos
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA
| |
Collapse
|
7
|
Rauch BJ, Porter JJ, Mehl RA, Perona JJ. Improved Incorporation of Noncanonical Amino Acids by an Engineered tRNA(Tyr) Suppressor. Biochemistry 2016; 55:618-28. [PMID: 26694948 DOI: 10.1021/acs.biochem.5b01185] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The Methanocaldcoccus jannaschii tyrosyl-tRNA synthetase (TyrRS):tRNA(Tyr) cognate pair has been used to incorporate a large number of noncanonical amino acids (ncAAs) into recombinant proteins in Escherichia coli. However, the structural elements of the suppressor tRNA(Tyr) used in these experiments have not been examined for optimal performance. Here, we evaluate the steady-state kinetic parameters of wild-type M. jannaschii TyrRS and an evolved 3-nitrotyrosyl-tRNA synthetase (nitroTyrRS) toward several engineered tRNA(Tyr) suppressors, and we correlate aminoacylation properties with the efficiency and fidelity of superfolder green fluorescent protein (sfGFP) synthesis in vivo. Optimal ncAA-sfGFP synthesis correlates with improved aminoacylation kinetics for a tRNA(Tyr) amber suppressor with two substitutions in the anticodon loop (G34C/G37A), while four additional mutations in the D and variable loops, present in the tRNA(Tyr) used in all directed evolution experiments to date, are deleterious to function both in vivo and in vitro. These findings extend to three of four other evolved TyrRS enzymes that incorporate distinct ncAAs. Suppressor tRNAs elicit decreases in amino acid Km values for both TyrRS and nitroTyrRS, suggesting that direct anticodon recognition by TyrRS need not be an impediment to superior performance of this orthogonal system and offering insight into novel approaches for directed evolution. The G34C/G37A tRNA(Tyr) may enhance future incorporation of many ncAAs by engineered TyrRS enzymes.
Collapse
Affiliation(s)
- Benjamin J Rauch
- Department of Chemistry, Portland State University , P.O. Box 751, Portland, Oregon 97207, United States.,Department of Biochemistry & Molecular Biology, Oregon Health & Sciences University , 3181 Southwest Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Joseph J Porter
- Department of Biochemistry and Biophysics, Oregon State University , 2011 Agriculture and Life Sciences Building, Corvallis, Oregon 97331, United States
| | - Ryan A Mehl
- Department of Biochemistry and Biophysics, Oregon State University , 2011 Agriculture and Life Sciences Building, Corvallis, Oregon 97331, United States
| | - John J Perona
- Department of Chemistry, Portland State University , P.O. Box 751, Portland, Oregon 97207, United States.,Department of Biochemistry & Molecular Biology, Oregon Health & Sciences University , 3181 Southwest Sam Jackson Park Road, Portland, Oregon 97239, United States
| |
Collapse
|
8
|
Igloi GL, Leisinger AK. Identity elements for the aminoacylation of metazoan mitochondrial tRNA(Arg) have been widely conserved throughout evolution and ensure the fidelity of the AGR codon reassignment. RNA Biol 2015; 11:1313-23. [PMID: 25603118 PMCID: PMC4615739 DOI: 10.1080/15476286.2014.996094] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Eumetazoan mitochondrial tRNAs possess structures (identity elements) that require the specific recognition by their cognate nuclear-encoded aminoacyl-tRNA synthetases. The AGA (arginine) codon of the standard genetic code has been reassigned to serine/glycine/termination in eumetazoan organelles and is translated in some organisms by a mitochondrially encoded tRNA(Ser)UCU. One mechanism to prevent mistranslation of the AGA codon as arginine would require a set of tRNA identity elements distinct from those possessed by the cytoplasmic tRNAArg in which the major identity elements permit the arginylation of all 5 encoded isoacceptors. We have performed comparative in vitro aminoacylation using an insect mitochondrial arginyl-tRNA synthetase and tRNAArgUCG structural variants. The established identity elements are sufficient to maintain the fidelity of tRNASerUCU reassignment. tRNAs having a UCU anticodon cannot be arginylated but can be converted to arginine acceptance by identity element transplantation. We have examined the evolutionary distribution and functionality of these tRNA elements within metazoan taxa. We conclude that the identity elements that have evolved for the recognition of mitochondrial tRNAArgUCG by the nuclear encoded mitochondrial arginyl-tRNA synthetases of eumetazoans have been extensively, but not universally conserved, throughout this clade. They ensure that the AGR codon reassignment in eumetazoan mitochondria is not compromised by misaminoacylation. In contrast, in other metazoans, such as Porifera, whose mitochondrial translation is dictated by the universal genetic code, recognition of the 2 encoded tRNAArgUCG/UCU isoacceptors is achieved through structural features that resemble those employed by the yeast cytoplasmic system.
Collapse
Affiliation(s)
- Gabor L Igloi
- a Institute of Biology III ; University of Freiburg ; Freiburg , Germany
| | | |
Collapse
|
9
|
Howard MJ, Klemm BP, Fierke CA. Mechanistic Studies Reveal Similar Catalytic Strategies for Phosphodiester Bond Hydrolysis by Protein-only and RNA-dependent Ribonuclease P. J Biol Chem 2015; 290:13454-64. [PMID: 25817998 DOI: 10.1074/jbc.m115.644831] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Indexed: 11/06/2022] Open
Abstract
Ribonuclease P (RNase P) is an endonuclease that catalyzes the essential removal of the 5' end of tRNA precursors. Until recently, all identified RNase P enzymes were a ribonucleoprotein with a conserved catalytic RNA component. However, the discovery of protein-only RNase P (PRORP) shifted this paradigm, affording a unique opportunity to compare mechanistic strategies used by naturally evolved protein and RNA-based enzymes that catalyze the same reaction. Here we investigate the enzymatic mechanism of pre-tRNA hydrolysis catalyzed by the NYN (Nedd4-BP1, YacP nuclease) metallonuclease of Arabidopsis thaliana, PRORP1. Multiple and single turnover kinetic data support a mechanism where a step at or before chemistry is rate-limiting and provide a kinetic framework to interpret the results of metal alteration, mutations, and pH dependence. Catalytic activity has a cooperative dependence on the magnesium concentration (nH = 2) under kcat/Km conditions, suggesting that PRORP1 catalysis is optimal with at least two active site metal ions, consistent with the crystal structure. Metal rescue of Asp-to-Ala mutations identified two aspartates important for enhancing metal ion affinity. The single turnover pH dependence of pre-tRNA cleavage revealed a single ionization (pKa ∼ 8.7) important for catalysis, consistent with deprotonation of a metal-bound water nucleophile. The pH and metal dependence mirrors that observed for the RNA-based RNase P, suggesting similar catalytic mechanisms. Thus, despite different macromolecular composition, the RNA and protein-based RNase P act as dynamic scaffolds for the binding and positioning of magnesium ions to catalyze phosphodiester bond hydrolysis.
Collapse
Affiliation(s)
| | | | - Carol A Fierke
- From the Departments of Biological Chemistry and Chemistry, University of Michigan, Ann Arbor, Michigan 48109
| |
Collapse
|