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Porat J, Kothe U, Bayfield MA. Revisiting tRNA chaperones: New players in an ancient game. RNA (NEW YORK, N.Y.) 2021; 27:rna.078428.120. [PMID: 33593999 PMCID: PMC8051267 DOI: 10.1261/rna.078428.120] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/10/2021] [Indexed: 05/03/2023]
Abstract
tRNAs undergo an extensive maturation process including post-transcriptional modifications that influence secondary and tertiary interactions. Precursor and mature tRNAs lacking key modifications are often recognized as aberrant and subsequently targeted for decay, illustrating the importance of modifications in promoting structural integrity. tRNAs also rely on tRNA chaperones to promote the folding of misfolded substrates into functional conformations. The best characterized tRNA chaperone is the La protein, which interacts with nascent RNA polymerase III transcripts to promote folding and offers protection from exonucleases. More recently, certain tRNA modification enzymes have also been demonstrated to possess tRNA folding activity distinct from their catalytic activity, suggesting that they may act as tRNA chaperones. In this review, we will discuss pioneering studies relating post-transcriptional modification to tRNA stability and decay pathways, present recent advances into the mechanism by which the RNA chaperone La assists pre-tRNA maturation, and summarize emerging research directions aimed at characterizing modification enzymes as tRNA chaperones. Together, these findings shed light on the importance of tRNA folding and how tRNA chaperones, in particular, increase the fraction of nascent pre-tRNAs that adopt a folded, functional conformation.
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52
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Post-Transcriptional Modifications of Conserved Nucleotides in the T-Loop of tRNA: A Tale of Functional Convergent Evolution. Genes (Basel) 2021; 12:genes12020140. [PMID: 33499018 PMCID: PMC7912444 DOI: 10.3390/genes12020140] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 12/30/2022] Open
Abstract
The high conservation of nucleotides of the T-loop, including their chemical identity, are hallmarks of tRNAs from organisms belonging to the three Domains of Life. These structural characteristics allow the T-loop to adopt a peculiar intraloop conformation able to interact specifically with other conserved residues of the D-loop, which ultimately folds the mature tRNA in a unique functional canonical L-shaped architecture. Paradoxically, despite the high conservation of modified nucleotides in the T-loop, enzymes catalyzing their formation depend mostly on the considered organism, attesting for an independent but convergent evolution of the post-transcriptional modification processes. The driving force behind this is the preservation of a native conformation of the tRNA elbow that underlies the various interactions of tRNA molecules with different cellular components.
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53
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Shetty S, Varshney U. Regulation of translation by one-carbon metabolism in bacteria and eukaryotic organelles. J Biol Chem 2021; 296:100088. [PMID: 33199376 PMCID: PMC7949028 DOI: 10.1074/jbc.rev120.011985] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 11/15/2020] [Accepted: 11/16/2020] [Indexed: 12/20/2022] Open
Abstract
Protein synthesis is an energetically costly cellular activity. It is therefore important that the process of mRNA translation remains in excellent synchrony with cellular metabolism and its energy reserves. Unregulated translation could lead to the production of incomplete, mistranslated, or misfolded proteins, squandering the energy needed for cellular sustenance and causing cytotoxicity. One-carbon metabolism (OCM), an integral part of cellular intermediary metabolism, produces a number of one-carbon unit intermediates (formyl, methylene, methenyl, methyl). These OCM intermediates are required for the production of amino acids such as methionine and other biomolecules such as purines, thymidylate, and redox regulators. In this review, we discuss how OCM impacts the translation apparatus (composed of ribosome, tRNA, mRNA, and translation factors) and regulates crucial steps in protein synthesis. More specifically, we address how the OCM metabolites regulate the fidelity and rate of translation initiation in bacteria and eukaryotic organelles such as mitochondria. Modulation of the fidelity of translation initiation by OCM opens new avenues to understand alternative translation mechanisms involved in stress tolerance and drug resistance.
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Affiliation(s)
- Sunil Shetty
- Biozentrum, University of Basel, Basel, Switzerland
| | - Umesh Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India; Jawaharlal Nehru Centre for Advanced Scientific Studies, Jakkur, Bangalore, India.
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54
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A substrate binding model for the KEOPS tRNA modifying complex. Nat Commun 2020; 11:6233. [PMID: 33277478 PMCID: PMC7718258 DOI: 10.1038/s41467-020-19990-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 11/02/2020] [Indexed: 11/09/2022] Open
Abstract
The KEOPS complex, which is conserved across archaea and eukaryotes, is composed of four core subunits; Pcc1, Kae1, Bud32 and Cgi121. KEOPS is crucial for the fitness of all organisms examined. In humans, pathogenic mutations in KEOPS genes lead to Galloway-Mowat syndrome, an autosomal-recessive disease causing childhood lethality. Kae1 catalyzes the universal and essential tRNA modification N6-threonylcarbamoyl adenosine, but the precise roles of all other KEOPS subunits remain an enigma. Here we show using structure-guided studies that Cgi121 recruits tRNA to KEOPS by binding to its 3' CCA tail. A composite model of KEOPS bound to tRNA reveals that all KEOPS subunits form an extended tRNA-binding surface that we have validated in vitro and in vivo to mediate the interaction with the tRNA substrate and its modification. These findings provide a framework for understanding the inner workings of KEOPS and delineate why all KEOPS subunits are essential.
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55
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Adami R, Bottai D. S-adenosylmethionine tRNA modification: unexpected/unsuspected implications of former/new players. Int J Biol Sci 2020; 16:3018-3027. [PMID: 33061813 PMCID: PMC7545696 DOI: 10.7150/ijbs.49302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/10/2020] [Indexed: 12/13/2022] Open
Abstract
S-adenosylmethionine supplies methyl groups to many acceptors, including lipids, proteins, RNA, DNA, and a wide range of small molecules. It acts as the precursor in the biosynthesis of metal ion chelating compounds, such as nicotianamine and phytosiderophores, of the polyamines spermidine and spermine and of some plant hormones. Finally, it is the source of catalytic 5′-deoxyadenosyl radicals. Radical S-adenosylmethionine (SAM) enzymes (RS) represent one of the most abundant groups (more than 100,000) of enzymes, exerting a plethora of biological functions, some of which are still unknown. In this work, we will focus on two RS: CDK5RAP1 and CDKAL1, both of which are involved in tRNA modifications that result in important tRNA folding and stability and in maintaining high translational fidelity. Based on this crucial role, their impairment can be important in the development of different human diseases.
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Affiliation(s)
- Raffaella Adami
- Department of Health Science University of Milan via A. di Rudinì 8 20142 Milan
| | - Daniele Bottai
- Department of Health Science University of Milan via A. di Rudinì 8 20142 Milan
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56
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Accornero F, Ross RL, Alfonzo JD. From canonical to modified nucleotides: balancing translation and metabolism. Crit Rev Biochem Mol Biol 2020; 55:525-540. [PMID: 32933330 DOI: 10.1080/10409238.2020.1818685] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Every type of nucleic acid in cells may undergo some kind of post-replicative or post-transcriptional chemical modification. Recent evidence has highlighted their importance in biology and their chemical complexity. In the following pages, we will describe new discoveries of modifications, with a focus on tRNA and mRNA. We will highlight current challenges and advances in modification detection and we will discuss how changes in nucleotide post-transcriptional modifications may affect cell homeostasis leading to malfunction. Although, RNA modifications prevail in all forms of life, the present review will focus on eukaryotic systems, where the great degree of intracellular compartmentalization provides barriers and filters for the level at which a given RNA is modified and will of course affect its fate and function. Additionally, although we will mention rRNA modification and modifications of the mRNA 5'-CAP structure, this will only be discussed in passing, as many substantive reviews have been written on these subjects. Here we will not spend much time describing all the possible modifications that have been observed; truly a daunting task. For reference, Bujnicki and coworkers have created MODOMICS, a useful repository for all types of modifications and their associated enzymes. Instead we will discuss a few examples, which illustrate our arguments on the connection of modifications, metabolism and ultimately translation. The fact remains, a full understanding of the long reach of nucleic acid modifications in cells requires both a global and targeted study of unprecedented scale, which at the moment may well be limited only by technology.
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Affiliation(s)
- Federica Accornero
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA.,The Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Robert L Ross
- Department of Chemistry, Rieveschl Laboratories for Mass Spectrometry, University of Cincinnati, Cincinnati, OH, USA
| | - Juan D Alfonzo
- The Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Microbiology, The Ohio State University, Columbus, OH, USA
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57
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Schultz SKL, Kothe U. tRNA elbow modifications affect the tRNA pseudouridine synthase TruB and the methyltransferase TrmA. RNA (NEW YORK, N.Y.) 2020; 26:1131-1142. [PMID: 32385137 PMCID: PMC7430675 DOI: 10.1261/rna.075473.120] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 05/04/2020] [Indexed: 05/20/2023]
Abstract
tRNAs constitute the most highly modified class of RNA. Every tRNA contains a unique set of modifications, and Ψ55, m5U54, and m7G46 are frequently found within the elbow of the tRNA structure. Despite the abundance of tRNA modifications, we are only beginning to understand the orchestration of modification enzymes during tRNA maturation. Here, we investigated whether pre-existing modifications impact the binding affinity or catalysis by tRNA elbow modification enzymes. Specifically, we focused on the Escherichia coli enzymes TruB, TrmA, and TrmB which generate Ψ55, m5U54, and m7G46, respectively. tRNAs containing a single modification were prepared, and the binding and activity preferences of purified E. coli TrmA, TruB, and TrmB were examined in vitro. TruB preferentially binds and modifies unmodified tRNA. TrmA prefers to modify unmodified tRNA, but binds most tightly to tRNA that already contains Ψ55. In contrast, binding and modification by TrmB is insensitive to the tRNA modification status. Our results suggest that TrmA and TruB are likely to act on mostly unmodified tRNA precursors during the early stages of tRNA maturation whereas TrmB presumably acts on later tRNA intermediates that are already partially modified. In conclusion, we uncover the mechanistic basis for the preferred modification order in the E. coli tRNA elbow region.
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Affiliation(s)
- Sarah Kai-Leigh Schultz
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada T1K 3M4
| | - Ute Kothe
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada T1K 3M4
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58
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Li J, Wang Y, Xu B, Liu Y, Zhou M, Long T, Li H, Dong H, Nie Y, Chen PR, Wang E, Liu R. Intellectual disability-associated gene ftsj1 is responsible for 2'-O-methylation of specific tRNAs. EMBO Rep 2020; 21:e50095. [PMID: 32558197 PMCID: PMC7403668 DOI: 10.15252/embr.202050095] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 05/24/2020] [Accepted: 05/27/2020] [Indexed: 12/31/2022] Open
Abstract
tRNA modifications at the anti-codon loop are critical for accurate decoding. FTSJ1 was hypothesized to be a human tRNA 2'-O-methyltransferase. tRNAPhe (GAA) from intellectual disability patients with mutations in ftsj1 lacks 2'-O-methylation at C32 and G34 (Cm32 and Gm34). However, the catalytic activity, RNA substrates, and pathogenic mechanism of FTSJ1 remain unknown, owing, in part, to the difficulty in reconstituting enzymatic activity in vitro. Here, we identify an interacting protein of FTSJ1, WDR6. For the first time, we reconstitute the 2'-O-methylation activity of the FTSJ1-WDR6 complex in vitro, which occurs at position 34 of specific tRNAs with m1 G37 as a prerequisite. We find that modifications at positions 32, 34, and 37 are interdependent and occur in a hierarchical order in vivo. We also show that the translation efficiency of the UUU codon, but not the UUC codon decoded by tRNAPhe (GAA), is reduced in ftsj1 knockout cells. Bioinformatics analysis reveals that almost 40% of the high TTT-biased genes are related to brain/nervous functions. Our data potentially enhance our understanding of the relationship between FTSJ1 and nervous system development.
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Affiliation(s)
- Jing Li
- State Key Laboratory of Molecular BiologyCAS Center for Excellence in Molecular Cell ScienceShanghai Institute of Biochemistry and Cell BiologyChinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
| | - Yan‐Nan Wang
- Shanghai Institute for Advanced Immunochemical StudiesShanghaiTech UniversityShanghaiChina
| | - Bei‐Si Xu
- Center for Applied BioinformaticsSt. Jude Children's Research HospitalMemphisTNUSA
| | - Ya‐Ping Liu
- Beijing National Laboratory for Molecular SciencesKey Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationSynthetic and Functional Biomolecules CenterCollege of Chemistry and Molecular EngineeringPeking UniversityBeijingChina
| | - Mi Zhou
- State Key Laboratory of Molecular BiologyCAS Center for Excellence in Molecular Cell ScienceShanghai Institute of Biochemistry and Cell BiologyChinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Tao Long
- State Key Laboratory of Molecular BiologyCAS Center for Excellence in Molecular Cell ScienceShanghai Institute of Biochemistry and Cell BiologyChinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Hao Li
- State Key Laboratory of Molecular BiologyCAS Center for Excellence in Molecular Cell ScienceShanghai Institute of Biochemistry and Cell BiologyChinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Han Dong
- State Key Laboratory of Molecular BiologyCAS Center for Excellence in Molecular Cell ScienceShanghai Institute of Biochemistry and Cell BiologyChinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Yan Nie
- Shanghai Institute for Advanced Immunochemical StudiesShanghaiTech UniversityShanghaiChina
| | - Peng R Chen
- Beijing National Laboratory for Molecular SciencesKey Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationSynthetic and Functional Biomolecules CenterCollege of Chemistry and Molecular EngineeringPeking UniversityBeijingChina
| | - En‐Duo Wang
- State Key Laboratory of Molecular BiologyCAS Center for Excellence in Molecular Cell ScienceShanghai Institute of Biochemistry and Cell BiologyChinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
| | - Ru‐Juan Liu
- School of Life Science and TechnologyShanghaiTech UniversityShanghaiChina
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59
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Lentini JM, Alsaif HS, Faqeih E, Alkuraya FS, Fu D. DALRD3 encodes a protein mutated in epileptic encephalopathy that targets arginine tRNAs for 3-methylcytosine modification. Nat Commun 2020; 11:2510. [PMID: 32427860 PMCID: PMC7237682 DOI: 10.1038/s41467-020-16321-6] [Citation(s) in RCA: 28] [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: 09/06/2019] [Accepted: 04/24/2020] [Indexed: 12/24/2022] Open
Abstract
In mammals, a subset of arginine tRNA isoacceptors are methylated in the anticodon loop by the METTL2 methyltransferase to form the 3-methylcytosine (m3C) modification. However, the mechanism by which METTL2 identifies specific tRNA arginine species for m3C formation as well as the biological role of m3C in mammals is unknown. Here, we show that human METTL2 forms a complex with DALR anticodon binding domain containing 3 (DALRD3) protein to recognize particular arginine tRNAs destined for m3C modification. DALRD3-deficient human cells exhibit nearly complete loss of the m3C modification in tRNA-Arg species. Notably, we identify a homozygous nonsense mutation in the DALRD3 gene that impairs m3C formation in human patients exhibiting developmental delay and early-onset epileptic encephalopathy. These findings uncover an unexpected function for the DALRD3 protein in the targeting of distinct arginine tRNAs for m3C modification and suggest a crucial biological role for DALRD3-dependent tRNA modification in proper neurological development.
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Affiliation(s)
- Jenna M Lentini
- Department of Biology, Center for RNA Biology, University of Rochester, Rochester, NY, USA
| | - Hessa S Alsaif
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Eissa Faqeih
- Section of Medical Genetics, Children's Specialist Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
- Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Dragony Fu
- Department of Biology, Center for RNA Biology, University of Rochester, Rochester, NY, USA.
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60
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He Q, Yang L, Gao K, Ding P, Chen Q, Xiong J, Yang W, Song Y, Wang L, Wang Y, Ling L, Wu W, Yan J, Zou P, Chen Y, Zhai R. FTSJ1 regulates tRNA 2'-O-methyladenosine modification and suppresses the malignancy of NSCLC via inhibiting DRAM1 expression. Cell Death Dis 2020; 11:348. [PMID: 32393790 PMCID: PMC7214438 DOI: 10.1038/s41419-020-2525-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/14/2020] [Accepted: 04/14/2020] [Indexed: 12/28/2022]
Abstract
Non-small cell lung cancer (NSCLC) is the leading cause of cancer mortality worldwide. The mechanisms underlying NSCLC tumorigenesis are incompletely understood. Transfer RNA (tRNA) modification is emerging as a novel regulatory mechanism for carcinogenesis. However, the role of tRNA modification in NSCLC remains obscure. In this study, HPLC/MS assay was used to quantify tRNA modification levels in NSCLC tissues and cells. tRNA-modifying enzyme genes were identified by comparative genomics and validated by qRT-PCR analysis. The biological functions of tRNA-modifying gene in NSCLC were investigated in vitro and in vivo. The mechanisms of tRNA-modifying gene in NSCLC were explored by RNA-seq, qRT-PCR, and rescue assays. The results showed that a total of 18 types of tRNA modifications and up to seven tRNA-modifying genes were significantly downregulated in NSCLC tumor tissues compared with that in normal tissues, with the 2'-O-methyladenosine (Am) modification displaying the lowest level in tumor tissues. Loss- and gain-of-function assays revealed that the amount of Am in tRNAs was significantly associated with expression levels of FTSJ1, which was also downregulated in NSCLC tissues and cells. Upregulation of FTSJ1 inhibited proliferation, migration, and promoted apoptosis of NSCLC cells in vitro. Silencing of FTSJ1 resulted in the opposite effects. In vivo assay confirmed that overexpression of FTSJ1 significantly suppressed the growth of NSCLC cells. Mechanistically, overexpression of FTSJ1 led to a decreased expression of DRAM1. Whereas knockdown of FTSJ1 resulted in an increased expression of DRAM1. Furthermore, silencing of DRAM1 substantially augmented the antitumor effect of FTSJ1 on NSCLC cells. Our findings suggested an important mechanism of tRNA modifications in NSCLC and demonstrated novel roles of FTSJ1 as both tRNA Am modifier and tumor suppressor in NSCLC.
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Affiliation(s)
- Qihan He
- School of Public Health, Guangdong Key Laboratory for Genome Stability & Disease Prevention, Carson Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China
| | - Lin Yang
- Department of Thoracic Surgery, Shenzhen People's Hospital, Shenzhen, 518020, China
| | - Kaiping Gao
- School of Public Health, Guangdong Key Laboratory for Genome Stability & Disease Prevention, Carson Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China
| | - Peikun Ding
- Department of Thoracic Surgery, Shenzhen People's Hospital, Shenzhen, 518020, China
| | - Qianqian Chen
- School of Public Health, Guangdong Key Laboratory for Genome Stability & Disease Prevention, Carson Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China
| | - Juan Xiong
- School of Public Health, Guangdong Key Laboratory for Genome Stability & Disease Prevention, Carson Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China
| | - Wenhan Yang
- School of Public Health, Guangdong Key Laboratory for Genome Stability & Disease Prevention, Carson Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China
| | - Yi Song
- School of Public Health, Guangdong Key Laboratory for Genome Stability & Disease Prevention, Carson Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China
| | - Liang Wang
- School of Public Health, Guangdong Key Laboratory for Genome Stability & Disease Prevention, Carson Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China
| | - Yejun Wang
- School of Public Health, Guangdong Key Laboratory for Genome Stability & Disease Prevention, Carson Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China
| | - Lijuan Ling
- Department of Thoracic Surgery, Shenzhen People's Hospital, Shenzhen, 518020, China
| | - Weiming Wu
- School of Public Health, Guangdong Key Laboratory for Genome Stability & Disease Prevention, Carson Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China
| | - Jisong Yan
- School of Public Health, Guangdong Key Laboratory for Genome Stability & Disease Prevention, Carson Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China
| | - Peng Zou
- School of Public Health, Guangdong Key Laboratory for Genome Stability & Disease Prevention, Carson Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China
| | - Yuchen Chen
- School of Public Health, Guangdong Key Laboratory for Genome Stability & Disease Prevention, Carson Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China
| | - Rihong Zhai
- School of Public Health, Guangdong Key Laboratory for Genome Stability & Disease Prevention, Carson Cancer Center, Shenzhen University Health Science Center, Shenzhen, 518055, China.
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61
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Khalique A, Mattijssen S, Haddad AF, Chaudhry S, Maraia RJ. Targeting mitochondrial and cytosolic substrates of TRIT1 isopentenyltransferase: Specificity determinants and tRNA-i6A37 profiles. PLoS Genet 2020; 16:e1008330. [PMID: 32324744 PMCID: PMC7200024 DOI: 10.1371/journal.pgen.1008330] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 05/05/2020] [Accepted: 03/18/2020] [Indexed: 11/29/2022] Open
Abstract
The tRNA isopentenyltransferases (IPTases), which add an isopentenyl group to N6 of A37 (i6A37) of certain tRNAs, are among a minority of enzymes that modify cytosolic and mitochondrial tRNAs. Pathogenic mutations to the human IPTase, TRIT1, that decrease i6A37 levels, cause mitochondrial insufficiency that leads to neurodevelopmental disease. We show that TRIT1 encodes an amino-terminal mitochondrial targeting sequence (MTS) that directs mitochondrial import and modification of mitochondrial-tRNAs. Full understanding of IPTase function must consider the tRNAs selected for modification, which vary among species, and in their cytosol and mitochondria. Selection is principally via recognition of the tRNA A36-A37-A38 sequence. An exception is unmodified tRNATrpCCA-A37-A38 in Saccharomyces cerevisiae, whereas tRNATrpCCA is readily modified in Schizosaccharomyces pombe, indicating variable IPTase recognition systems and suggesting that additional exceptions may account for some of the tRNA-i6A37 paucity in higher eukaryotes. Yet TRIT1 had not been characterized for restrictive type substrate-specific recognition. We used i6A37-dependent tRNA-mediated suppression and i6A37-sensitive northern blotting to examine IPTase activities in S. pombe and S. cerevisiae lacking endogenous IPTases on a diversity of tRNA-A36-A37-A38 substrates. Point mutations to the TRIT1 MTS that decrease human mitochondrial import, decrease modification of mitochondrial but not cytosolic tRNAs in both yeasts. TRIT1 exhibits clear substrate-specific restriction against a cytosolic-tRNATrpCCA-A37-A38. Additional data suggest that position 32 of tRNATrpCCA is a conditional determinant for substrate-specific i6A37 modification by the restrictive IPTases, Mod5 and TRIT1. The cumulative biochemical and phylogenetic sequence analyses provide new insights into IPTase activities and determinants of tRNA-i6A37 profiles in cytosol and mitochondria.
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Affiliation(s)
- Abdul Khalique
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sandy Mattijssen
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
| | - Alexander F. Haddad
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
| | - Shereen Chaudhry
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
| | - Richard J. Maraia
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health, Bethesda, Maryland, United States of America
- Commissioned Corps, United States Public Health Service, Rockville, Maryland, United States of America
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62
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2,6-Diaminopurine as a highly potent corrector of UGA nonsense mutations. Nat Commun 2020; 11:1509. [PMID: 32198346 PMCID: PMC7083880 DOI: 10.1038/s41467-020-15140-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 02/21/2020] [Indexed: 12/21/2022] Open
Abstract
Nonsense mutations cause about 10% of genetic disease cases, and no treatments are available. Nonsense mutations can be corrected by molecules with nonsense mutation readthrough activity. An extract of the mushroom Lepista inversa has recently shown high-efficiency correction of UGA and UAA nonsense mutations. One active constituent of this extract is 2,6-diaminopurine (DAP). In Calu-6 cancer cells, in which TP53 gene has a UGA nonsense mutation, DAP treatment increases p53 level. It also decreases the growth of tumors arising from Calu-6 cells injected into immunodeficient nude mice. DAP acts by interfering with the activity of a tRNA-specific 2′-O-methyltransferase (FTSJ1) responsible for cytosine 34 modification in tRNATrp. Low-toxicity and high-efficiency UGA nonsense mutation correction make DAP a good candidate for the development of treatments for genetic diseases caused by nonsense mutations. Nonsense mutations can be corrected by several molecules that activate readthrough of premature termination codon. Here, the authors report that 2,6-diaminopurine efficiently corrects UGA nonsense mutations with no significant toxicity.
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63
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Pollo-Oliveira L, Klassen R, Davis N, Ciftci A, Bacusmo JM, Martinelli M, DeMott MS, Begley TJ, Dedon PC, Schaffrath R, de Crécy-Lagard V. Loss of Elongator- and KEOPS-Dependent tRNA Modifications Leads to Severe Growth Phenotypes and Protein Aggregation in Yeast. Biomolecules 2020; 10:E322. [PMID: 32085421 PMCID: PMC7072221 DOI: 10.3390/biom10020322] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 12/20/2022] Open
Abstract
Modifications found in the Anticodon Stem Loop (ASL) of tRNAs play important roles in regulating translational speed and accuracy. Threonylcarbamoyl adenosine (t6A37) and 5-methoxycarbonyl methyl-2-thiouridine (mcm5s2U34) are critical ASL modifications that have been linked to several human diseases. The model yeast Saccharomyces cerevisiae is viable despite the absence of both modifications, growth is however greatly impaired. The major observed consequence is a subsequent increase in protein aggregates and aberrant morphology. Proteomic analysis of the t6A-deficient strain (sua5 mutant) revealed a global mistranslation leading to protein aggregation without regard to physicochemical properties or t6A-dependent or biased codon usage in parent genes. However, loss of sua5 led to increased expression of soluble proteins for mitochondrial function, protein quality processing/trafficking, oxidative stress response, and energy homeostasis. These results point to a global function for t6A in protein homeostasis very similar to mcm5/s2U modifications.
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Affiliation(s)
- Leticia Pollo-Oliveira
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32603, USA; (L.P.-O.); (J.M.B.); (M.M.)
| | - Roland Klassen
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, 34132 Kassel, Germany; (R.K.); (A.C.); (R.S.)
| | - Nick Davis
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; (N.D.); (M.S.D.); (P.C.D.)
| | - Akif Ciftci
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, 34132 Kassel, Germany; (R.K.); (A.C.); (R.S.)
| | - Jo Marie Bacusmo
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32603, USA; (L.P.-O.); (J.M.B.); (M.M.)
| | - Maria Martinelli
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32603, USA; (L.P.-O.); (J.M.B.); (M.M.)
| | - Michael S. DeMott
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; (N.D.); (M.S.D.); (P.C.D.)
| | - Thomas J. Begley
- The RNA Institute, College of Arts and Science, University at Albany, SUNY, Albany, NY 12222, USA;
| | - Peter C. Dedon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; (N.D.); (M.S.D.); (P.C.D.)
| | - Raffael Schaffrath
- Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, 34132 Kassel, Germany; (R.K.); (A.C.); (R.S.)
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32603, USA; (L.P.-O.); (J.M.B.); (M.M.)
- University of Florida Genetics Institute, Gainesville, FL 32608, USA
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Barraud P, Tisné C. To be or not to be modified: Miscellaneous aspects influencing nucleotide modifications in tRNAs. IUBMB Life 2019; 71:1126-1140. [PMID: 30932315 PMCID: PMC6850298 DOI: 10.1002/iub.2041] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/10/2019] [Indexed: 12/12/2022]
Abstract
Transfer RNAs (tRNAs) are essential components of the cellular protein synthesis machineries, but are also implicated in many roles outside translation. To become functional, tRNAs, initially transcribed as longer precursor tRNAs, undergo a tightly controlled biogenesis process comprising the maturation of their extremities, removal of intronic sequences if present, addition of the 3'-CCA amino-acid accepting sequence, and aminoacylation. In addition, the most impressive feature of tRNA biogenesis consists in the incorporation of a large number of posttranscriptional chemical modifications along its sequence. The chemical nature of these modifications is highly diverse, with more than hundred different modifications identified in tRNAs to date. All functions of tRNAs in cells are controlled and modulated by modifications, making the understanding of the mechanisms that determine and influence nucleotide modifications in tRNAs an essential point in tRNA biology. This review describes the different aspects that determine whether a certain position in a tRNA molecule is modified or not. We describe how sequence and structural determinants, as well as the presence of prior modifications control modification processes. We also describe how environmental factors and cellular stresses influence the level and/or the nature of certain modifications introduced in tRNAs, and report situations where these dynamic modulations of tRNA modification levels are regulated by active demodification processes. © 2019 IUBMB Life, 71(8):1126-1140, 2019.
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Affiliation(s)
- Pierre Barraud
- Expression génétique microbienneInstitut de biologie physico‐chimique (IBPC), UMR 8261, CNRS, Université Paris DiderotParisFrance
| | - Carine Tisné
- Expression génétique microbienneInstitut de biologie physico‐chimique (IBPC), UMR 8261, CNRS, Université Paris DiderotParisFrance
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Abstract
Although the biological importance of post-transcriptional RNA modifications in gene expression is widely appreciated, methods to directly detect their introduction during RNA biosynthesis are rare and do not easily provide information on the temporal nature of events. Here, we introduce the application of NMR spectroscopy to observe the maturation of tRNAs in cell extracts. By following the maturation of yeast tRNAPhe with time-resolved NMR measurements, we show that modifications are introduced in a defined sequential order, and that the chronology is controlled by cross-talk between modification events. In particular, we show that a strong hierarchy controls the introduction of the T54, Ψ55 and m1A58 modifications in the T-arm, and we demonstrate that the modification circuits identified in yeast extract with NMR also impact the tRNA modification process in living cells. The NMR-based methodology presented here could be adapted to investigate different aspects of tRNA maturation and RNA modifications in general. Transfer RNA (tRNA) is regulated by RNA modifications. Here the authors employ time-resolved NMR to monitor modifications of yeast tRNAPhe in cellular extracts, revealing a sequential order and cross-talk between modifications.
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66
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Metazoan tsRNAs: Biogenesis, Evolution and Regulatory Functions. Noncoding RNA 2019; 5:ncrna5010018. [PMID: 30781726 PMCID: PMC6468576 DOI: 10.3390/ncrna5010018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 01/30/2019] [Accepted: 02/12/2019] [Indexed: 12/15/2022] Open
Abstract
Transfer RNA-derived small RNAs (tsRNAs) are an emerging class of regulatory non-coding RNAs that play important roles in post-transcriptional regulation across a variety of biological processes. Here, we review the recent advances in tsRNA biogenesis and regulatory functions from the perspectives of functional and evolutionary genomics, with a focus on the tsRNA biology of Drosophila. We first summarize our current understanding of the biogenesis mechanisms of different categories of tsRNAs that are generated under physiological or stressed conditions. Next, we review the conservation patterns of tsRNAs in all domains of life, with an emphasis on the conservation of tsRNAs between two Drosophila species. Then, we elaborate the currently known regulatory functions of tsRNAs in mRNA translation that are independent of, or dependent on, Argonaute (AGO) proteins. We also highlight some issues related to the fundamental biology of tsRNAs that deserve further study.
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Dixit S, Henderson JC, Alfonzo JD. Multi-Substrate Specificity and the Evolutionary Basis for Interdependence in tRNA Editing and Methylation Enzymes. Front Genet 2019; 10:104. [PMID: 30838029 PMCID: PMC6382703 DOI: 10.3389/fgene.2019.00104] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/30/2019] [Indexed: 12/12/2022] Open
Abstract
Among tRNA modification enzymes there is a correlation between specificity for multiple tRNA substrates and heteromultimerization. In general, enzymes that modify a conserved residue in different tRNA sequences adopt a heterodimeric structure. Presumably, such changes in the oligomeric state of enzymes, to gain multi-substrate recognition, are driven by the need to accommodate and catalyze a particular reaction in different substrates while maintaining high specificity. This review focuses on two classes of enzymes where the case for multimerization as a way to diversify molecular recognition can be made. We will highlight several new themes with tRNA methyltransferases and will also discuss recent findings with tRNA editing deaminases. These topics will be discussed in the context of several mechanisms by which heterodimerization may have been achieved during evolution and how these mechanisms might impact modifications in different systems.
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Affiliation(s)
| | | | - Juan D. Alfonzo
- Department of Microbiology, The Ohio State Biochemistry Program, The Center for RNA Biology, The Ohio State University, Columbus, OH, United States
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68
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The emerging impact of tRNA modifications in the brain and nervous system. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:412-428. [PMID: 30529455 DOI: 10.1016/j.bbagrm.2018.11.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 11/21/2018] [Accepted: 11/23/2018] [Indexed: 01/19/2023]
Abstract
A remarkable number of neurodevelopmental disorders have been linked to defects in tRNA modifications. These discoveries place tRNA modifications in the spotlight as critical modulators of gene expression pathways that are required for proper organismal growth and development. Here, we discuss the emerging molecular and cellular functions of the diverse tRNA modifications linked to cognitive and neurological disorders. In particular, we describe how the structure and location of a tRNA modification influences tRNA folding, stability, and function. We then highlight how modifications in tRNA can impact multiple aspects of protein translation that are instrumental for maintaining proper cellular proteostasis. Importantly, we describe how perturbations in tRNA modification lead to a spectrum of deleterious biological outcomes that can disturb neurodevelopment and neurological function. Finally, we summarize the biological themes shared by the different tRNA modifications linked to cognitive disorders and offer insight into the future questions that remain to decipher the role of tRNA modifications. This article is part of a Special Issue entitled: mRNA modifications in gene expression control edited by Dr. Soller Matthias and Dr. Fray Rupert.
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