1
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Shuman S. RNA Repair: Hiding in Plain Sight. Annu Rev Genet 2023; 57:461-489. [PMID: 37722686 DOI: 10.1146/annurev-genet-071719-021856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
Enzymes that phosphorylate, dephosphorylate, and ligate RNA 5' and 3' ends were discovered more than half a century ago and were eventually shown to repair purposeful site-specific endonucleolytic breaks in the RNA phosphodiester backbone. The pace of discovery and characterization of new candidate RNA repair activities in taxa from all phylogenetic domains greatly exceeds our understanding of the biological pathways in which they act. The key questions anent RNA break repair in vivo are (a) identifying the triggers, agents, and targets of RNA cleavage and (b) determining whether RNA repair results in restoration of the original RNA, modification of the RNA (by loss or gain at the ends), or rearrangements of the broken RNA segments (i.e., RNA recombination). This review provides a perspective on the discovery, mechanisms, and physiology of purposeful RNA break repair, highlighting exemplary repair pathways (e.g., tRNA restriction-repair and tRNA splicing) for which genetics has figured prominently in their elucidation.
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Affiliation(s)
- Stewart Shuman
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA;
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2
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Saito M, Inose R, Sato A, Tomita M, Suzuki H, Kanai A. Systematic Analysis of Diverse Polynucleotide Kinase Clp1 Family Proteins in Eukaryotes: Three Unique Clp1 Proteins of Trypanosoma brucei. J Mol Evol 2023; 91:669-686. [PMID: 37606665 PMCID: PMC10598085 DOI: 10.1007/s00239-023-10128-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 08/01/2023] [Indexed: 08/23/2023]
Abstract
The Clp1 family proteins, consisting of the Clp1 and Nol9/Grc3 groups, have polynucleotide kinase (PNK) activity at the 5' end of RNA strands and are important enzymes in the processing of some precursor RNAs. However, it remains unclear how this enzyme family diversified in the eukaryotes. We performed a large-scale molecular evolutionary analysis of the full-length genomes of 358 eukaryotic species to classify the diverse Clp1 family proteins. The average number of Clp1 family proteins in eukaryotes was 2.3 ± 1.0, and most representative species had both Clp1 and Nol9/Grc3 proteins, suggesting that the Clp1 and Nol9/Grc3 groups were already formed in the eukaryotic ancestor by gene duplication. We also detected an average of 4.1 ± 0.4 Clp1 family proteins in members of the protist phylum Euglenozoa. For example, in Trypanosoma brucei, there are three genes of the Clp1 group and one gene of the Nol9/Grc3 group. In the Clp1 group proteins encoded by these three genes, the C-terminal domains have been replaced by unique characteristics domains, so we designated these proteins Tb-Clp1-t1, Tb-Clp1-t2, and Tb-Clp1-t3. Experimental validation showed that only Tb-Clp1-t2 has PNK activity against RNA strands. As in this example, N-terminal and C-terminal domain replacement also contributed to the diversification of the Clp1 family proteins in other eukaryotic species. Our analysis also revealed that the Clp1 family proteins in humans and plants diversified through isoforms created by alternative splicing.
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Affiliation(s)
- Motofumi Saito
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0017, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, 252-0882, Japan
| | - Rerina Inose
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0017, Japan
| | - Asako Sato
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0017, Japan
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0017, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, 252-0882, Japan
- Faculty of Environment and Information Studies, Keio University, Fujisawa, 252-0882, Japan
| | - Haruo Suzuki
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0017, Japan
- Faculty of Environment and Information Studies, Keio University, Fujisawa, 252-0882, Japan
| | - Akio Kanai
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0017, Japan.
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, 252-0882, Japan.
- Faculty of Environment and Information Studies, Keio University, Fujisawa, 252-0882, Japan.
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3
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Hayne CK, Sekulovski S, Hurtig JE, Stanley RE, Trowitzsch S, van Hoof A. New insights into RNA processing by the eukaryotic tRNA splicing endonuclease. J Biol Chem 2023; 299:105138. [PMID: 37544645 PMCID: PMC10485636 DOI: 10.1016/j.jbc.2023.105138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 07/27/2023] [Accepted: 07/29/2023] [Indexed: 08/08/2023] Open
Abstract
Through its role in intron cleavage, tRNA splicing endonuclease (TSEN) plays a critical function in the maturation of intron-containing pre-tRNAs. The catalytic mechanism and core requirement for this process is conserved between archaea and eukaryotes, but for decades, it has been known that eukaryotic TSENs have evolved additional modes of RNA recognition, which have remained poorly understood. Recent research identified new roles for eukaryotic TSEN, including processing or degradation of additional RNA substrates, and determined the first structures of pre-tRNA-bound human TSEN complexes. These recent discoveries have changed our understanding of how the eukaryotic TSEN targets and recognizes substrates. Here, we review these recent discoveries, their implications, and the new questions raised by these findings.
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Affiliation(s)
- Cassandra K Hayne
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.
| | - Samoil Sekulovski
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Jennifer E Hurtig
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National, Institutes of Health, Research Triangle Park, North Carolina, USA.
| | - Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt am Main, Germany.
| | - Ambro van Hoof
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas, USA.
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4
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Abstract
The study of eukaryotic tRNA processing has given rise to an explosion of new information and insights in the last several years. We now have unprecedented knowledge of each step in the tRNA processing pathway, revealing unexpected twists in biochemical pathways, multiple new connections with regulatory pathways, and numerous biological effects of defects in processing steps that have profound consequences throughout eukaryotes, leading to growth phenotypes in the yeast Saccharomyces cerevisiae and to neurological and other disorders in humans. This review highlights seminal new results within the pathways that comprise the life of a tRNA, from its birth after transcription until its death by decay. We focus on new findings and revelations in each step of the pathway including the end-processing and splicing steps, many of the numerous modifications throughout the main body and anticodon loop of tRNA that are so crucial for tRNA function, the intricate tRNA trafficking pathways, and the quality control decay pathways, as well as the biogenesis and biology of tRNA-derived fragments. We also describe the many interactions of these pathways with signaling and other pathways in the cell.
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Affiliation(s)
- Eric M Phizicky
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine, Rochester, New York 14642, USA
| | - Anita K Hopper
- Department of Molecular Genetics and Center for RNA Biology, Ohio State University, Columbus, Ohio 43235, USA
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5
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Chatterjee K, Marshall WA, Hopper AK. Three tRNA nuclear exporters in S. cerevisiae: parallel pathways, preferences, and precision. Nucleic Acids Res 2022; 50:10140-10152. [PMID: 36099418 PMCID: PMC9508810 DOI: 10.1093/nar/gkac754] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/11/2022] [Accepted: 09/02/2022] [Indexed: 11/15/2022] Open
Abstract
tRNAs that are transcribed in the nucleus are exported to the cytoplasm to perform their iterative essential function in translation. However, the complex set of tRNA post-transcriptional processing and subcellular trafficking steps are not completely understood. In particular, proteins involved in tRNA nuclear export remain unknown since the canonical tRNA nuclear exportin, Los1/Exportin-t, is unessential in all tested organisms. We previously reported that budding yeast Mex67-Mtr2, a mRNA nuclear exporter, co-functions with Los1 in tRNA nuclear export. Here we employed in vivo co-purification of tRNAs with endogenously expressed nuclear exporters to document that Crm1 also is a bona fide tRNA nuclear exporter. We document that Los1, Mex67-Mtr2 and Crm1 possess individual tRNA preferences for forming nuclear export complexes with members of the 10 families of intron-containing pre-tRNAs. Remarkably, Mex67-Mtr2, but not Los1 or Crm1, is error-prone, delivering tRNAs to the cytoplasm prior to 5′ leader removal. tRNA retrograde nuclear import functions to monitor the aberrant leader-containing spliced tRNAs, returning them to the nucleus where they are degraded by 3′ to 5′ exonucleases. Overall, our work identifies a new tRNA nuclear exporter, uncovers exporter preferences for specific tRNA families, and documents contribution of tRNA nuclear import to tRNA quality control.
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Affiliation(s)
- Kunal Chatterjee
- Department of Molecular Genetics, Ohio State University, Columbus, OH 43235, USA.,Center for RNA Biology, Ohio State University, Columbus, OH 43235, USA
| | - William A Marshall
- Department of Molecular Genetics, Ohio State University, Columbus, OH 43235, USA
| | - Anita K Hopper
- Department of Molecular Genetics, Ohio State University, Columbus, OH 43235, USA.,Center for RNA Biology, Ohio State University, Columbus, OH 43235, USA
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6
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Hegedűsová E, Maršalová V, Kulkarni S, Paris Z. Trafficking and/or division: Distinct roles of nucleoporins based on their location within the nuclear pore complex. RNA Biol 2022; 19:650-661. [PMID: 35491934 PMCID: PMC9067531 DOI: 10.1080/15476286.2022.2067711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The nuclear pore complex (NPC) facilitates the trafficking of proteins and RNA between the nucleus and cytoplasm. The role of nucleoporins (Nups) in transport in the context of the NPC is well established, yet their function in tRNA export has not been fully explored. We selected several nucleoporins from different parts of the NPC to investigate their potential role in tRNA trafficking in Trypanosoma brucei. We show that while all of the nucleoporins studied are essential for cell viability, only TbNup62 and TbNup53a function in tRNA export. In contrast to homologs in yeast TbNup144 and TbNup158, which are part of the inner and outer ring of the NPC, have no role in nuclear tRNA trafficking. Instead, TbNup144 plays a critical role in nuclear division, highlighting the role of nucleoporins beyond nucleocytoplasmic transport. These results suggest that the location of nucleoporins within the NPC is crucial to maintaining various cellular processes.
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Affiliation(s)
- Eva Hegedűsová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Veronika Maršalová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Sneha Kulkarni
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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7
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Lateef OM, Akintubosun MO, Olaoba OT, Samson SO, Adamczyk M. Making Sense of "Nonsense" and More: Challenges and Opportunities in the Genetic Code Expansion, in the World of tRNA Modifications. Int J Mol Sci 2022; 23:938. [PMID: 35055121 PMCID: PMC8779196 DOI: 10.3390/ijms23020938] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 01/09/2023] Open
Abstract
The evolutional development of the RNA translation process that leads to protein synthesis based on naturally occurring amino acids has its continuation via synthetic biology, the so-called rational bioengineering. Genetic code expansion (GCE) explores beyond the natural translational processes to further enhance the structural properties and augment the functionality of a wide range of proteins. Prokaryotic and eukaryotic ribosomal machinery have been proven to accept engineered tRNAs from orthogonal organisms to efficiently incorporate noncanonical amino acids (ncAAs) with rationally designed side chains. These side chains can be reactive or functional groups, which can be extensively utilized in biochemical, biophysical, and cellular studies. Genetic code extension offers the contingency of introducing more than one ncAA into protein through frameshift suppression, multi-site-specific incorporation of ncAAs, thereby increasing the vast number of possible applications. However, different mediating factors reduce the yield and efficiency of ncAA incorporation into synthetic proteins. In this review, we comment on the recent advancements in genetic code expansion to signify the relevance of systems biology in improving ncAA incorporation efficiency. We discuss the emerging impact of tRNA modifications and metabolism in protein design. We also provide examples of the latest successful accomplishments in synthetic protein therapeutics and show how codon expansion has been employed in various scientific and biotechnological applications.
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Affiliation(s)
- Olubodun Michael Lateef
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland; (O.M.L.); (M.O.A.); (S.O.S.)
| | | | - Olamide Tosin Olaoba
- Laboratory of Functional and Structural Biochemistry, Federal University of Sao Carlos, Sao Carlos 13565-905, SP, Brazil;
| | - Sunday Ocholi Samson
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland; (O.M.L.); (M.O.A.); (S.O.S.)
| | - Malgorzata Adamczyk
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland; (O.M.L.); (M.O.A.); (S.O.S.)
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8
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Peng R, Yoshinari S, Kawano-Sugaya T, Jeelani G, Nozaki T. Identification and Functional Characterization of Divergent 3'-Phosphate tRNA Ligase From Entamoeba histolytica. Front Cell Infect Microbiol 2022; 11:746261. [PMID: 34976851 PMCID: PMC8718801 DOI: 10.3389/fcimb.2021.746261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 11/24/2021] [Indexed: 11/13/2022] Open
Abstract
HSPC117/RtcB, 3'-phosphate tRNA ligase, is a critical enzyme involved in tRNA splicing and maturation. HSPC117/RtcB is also involved in mRNA splicing of some protein-coding genes including XBP-1. Entamoeba histolytica, a protozoan parasite responsible for human amebiasis, possesses two RtcB proteins (EhRtcB1 and 2), but their biological functions remain unknown. Both RtcBs show kinship with mammalian/archaeal type, and all amino acid residues present in the active sites are highly conserved, as suggested by protein alignment and phylogenetic analyses. EhRtcB1 was demonstrated to be localized to the nucleus, while EhRtcB2 was in the cytosol. EhRtcB1, but not EhRtcB2, was required for optimal growth of E. histolytica trophozoites. Both EhRtcB1 (in cooperation with EhArchease) and EhRtcB2 showed RNA ligation activity in vitro. The predominant role of EhRtcB1 in tRNAIle(UAU) processing in vivo was demonstrated in EhRtcB1- and 2-gene silenced strains. Taken together, we have demonstrated the conservation of tRNA splicing and functional diversification of RtcBs in this amoebozoan lineage.
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Affiliation(s)
- Ruofan Peng
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shigeo Yoshinari
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tetsuro Kawano-Sugaya
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Ghulam Jeelani
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tomoyoshi Nozaki
- Laboratory of Biomedical Chemistry, Department of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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9
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Dixit S, Kessler AC, Henderson J, Pan X, Zhao R, D'Almeida GS, Kulkarni S, Rubio MAT, Hegedűsová E, Ross RL, Limbach PA, Green BD, Paris Z, Alfonzo JD. Dynamic queuosine changes in tRNA couple nutrient levels to codon choice in Trypanosoma brucei. Nucleic Acids Res 2021; 49:12986-12999. [PMID: 34883512 PMCID: PMC8682783 DOI: 10.1093/nar/gkab1204] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/16/2021] [Accepted: 12/08/2021] [Indexed: 11/22/2022] Open
Abstract
Every type of nucleic acid in cells undergoes programmed chemical post-transcriptional modification. Generally, modification enzymes use substrates derived from intracellular metabolism, one exception is queuine (q)/queuosine (Q), which eukaryotes obtain from their environment; made by bacteria and ultimately taken into eukaryotic cells via currently unknown transport systems. Here, we use a combination of molecular, cell biology and biophysical approaches to show that in Trypanosoma brucei tRNA Q levels change dynamically in response to concentration variations of a sub-set of amino acids in the growth media. Most significant were variations in tyrosine, which at low levels lead to increased Q content for all the natural tRNAs substrates of tRNA-guanine transglycosylase (TGT). Such increase results from longer nuclear dwell time aided by retrograde transport following cytoplasmic splicing. In turn high tyrosine levels lead to rapid decrease in Q content. Importantly, the dynamic changes in Q content of tRNAs have negligible effects on global translation or growth rate but, at least, in the case of tRNATyr it affected codon choice. These observations have implications for the occurrence of other tunable modifications important for ‘normal’ growth, while connecting the intracellular localization of modification enzymes, metabolites and tRNAs to codon selection and implicitly translational output.
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Affiliation(s)
- Sameer Dixit
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Alan C Kessler
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Jeremy Henderson
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Xiaobei Pan
- School of Biological Sciences, Institute for Global Food Security, Queen's University Belfast, Belfast, UK
| | - Ruoxia Zhao
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, OH, USA
| | | | - Sneha Kulkarni
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Mary Anne T Rubio
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Eva Hegedűsová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Robert L Ross
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, OH, USA
| | - Patrick A Limbach
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, OH, USA
| | - Brian D Green
- School of Biological Sciences, Institute for Global Food Security, Queen's University Belfast, Belfast, UK
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Juan D Alfonzo
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA
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10
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Hegedűsová E, Kulkarni S, Burgman B, Alfonzo JD, Paris Z. The general mRNA exporters Mex67 and Mtr2 play distinct roles in nuclear export of tRNAs in Trypanosoma brucei. Nucleic Acids Res 2019; 47:8620-8631. [PMID: 31392978 PMCID: PMC6794378 DOI: 10.1093/nar/gkz671] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/18/2019] [Accepted: 07/29/2019] [Indexed: 01/09/2023] Open
Abstract
Transfer RNAs (tRNAs) are central players in protein synthesis, which in Eukarya need to be delivered from the nucleus to the cytoplasm by specific transport receptors, most of which belong to the evolutionarily conserved beta-importin family. Based on the available literature, we identified two candidates, Xpo-t and Xpo-5 for tRNA export in Trypanosoma brucei. However, down-regulation of expression of these genes did not disrupt the export of tRNAs to the cytoplasm. In search of alternative pathways, we tested the mRNA export complex Mex67-Mtr2, for a role in tRNA nuclear export, as described previously in yeast. Down-regulation of either exporter affected the subcellular distribution of tRNAs. However, contrary to yeast, TbMex67 and TbMtr2 accumulated different subsets of tRNAs in the nucleus. While TbMtr2 perturbed the export of all the tRNAs tested, silencing of TbMex67, led to the nuclear accumulation of tRNAs that are typically modified with queuosine. In turn, inhibition of tRNA nuclear export also affected the levels of queuosine modification in tRNAs. Taken together, the results presented demonstrate the dynamic nature of tRNA trafficking in T. brucei and its potential impact not only on the availability of tRNAs for protein synthesis but also on their modification status.
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Affiliation(s)
- Eva Hegedűsová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Sneha Kulkarni
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Brandon Burgman
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,The University of Arizona, Tucson, AZ, USA
| | - Juan D Alfonzo
- Department of Microbiology, Ohio State Biochemistry Program and The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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11
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Banerjee A, Ghosh S, Goldgur Y, Shuman S. Structure and two-metal mechanism of fungal tRNA ligase. Nucleic Acids Res 2019; 47:1428-1439. [PMID: 30590734 PMCID: PMC6379707 DOI: 10.1093/nar/gky1275] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/10/2018] [Accepted: 12/11/2018] [Indexed: 02/06/2023] Open
Abstract
Fungal tRNA ligase (Trl1) is an essential enzyme that repairs RNA breaks with 2′,3′-cyclic-PO4 and 5′-OH ends inflicted during tRNA splicing and non-canonical mRNA splicing in the fungal unfolded protein response. Trl1 is composed of C-terminal cyclic phosphodiesterase (CPD) and central GTP-dependent polynucleotide kinase (KIN) domains that heal the broken ends to generate the 3′-OH,2′-PO4 and 5′-PO4 termini required for sealing by an N-terminal ATP-dependent ligase domain (LIG). Here we report crystal structures of the Trl1-LIG domain from Chaetomium thermophilum at two discrete steps along the reaction pathway: the covalent LIG-(lysyl-Nζ)–AMP•Mn2+ intermediate and a LIG•ATP•(Mn2+)2 Michaelis complex. The structures highlight a two-metal mechanism whereby a penta-hydrated metal complex stabilizes the transition state of the ATP α phosphate and a second metal bridges the β and γ phosphates to help orient the pyrophosphate leaving group. A LIG-bound sulfate anion is a plausible mimetic of the essential RNA terminal 2′-PO4. Trl1-LIG has a distinctive C-terminal domain that instates fungal Trl1 as the founder of an Rnl6 clade of ATP-dependent RNA ligase. We discuss how the Trl1-LIG structure rationalizes the large body of in vivo structure–function data for Saccharomyces cerevisiae Trl1.
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Affiliation(s)
- Ankan Banerjee
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Shreya Ghosh
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Yehuda Goldgur
- Structural Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Stewart Shuman
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
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12
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Paris Z, Alfonzo JD. How the intracellular partitioning of tRNA and tRNA modification enzymes affects mitochondrial function. IUBMB Life 2018; 70:1207-1213. [PMID: 30358065 DOI: 10.1002/iub.1957] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 09/21/2018] [Indexed: 11/06/2022]
Abstract
Organisms have evolved different strategies to seclude certain molecules to specific locations of the cell. This is most pronounced in eukaryotes with their extensive intracellular membrane systems. Intracellular compartmentalization is particularly critical in genome containing organelles, which because of their bacterial evolutionary ancestry still maintain protein-synthesis machinery that resembles more their evolutionary origin than the extant eukaryotic cell they once joined as an endosymbiont. Despite this, it is clear that genome-containing organelles such as the mitochondria are not in isolation and many molecules make it across the mitochondrial membranes from the cytoplasm. In this realm the import of tRNAs and the enzymes that modify them prove most consequential. In this review, we discuss two recent examples of how modifications typically found in cytoplasmic tRNAs affect mitochondrial translation in organisms that forcibly import all their tRNAs from the cytoplasm. In our view, the combination of tRNA import and the compartmentalization of modification enzymes must have played a critical role in the evolution of the organelle. © 2018 IUBMB Life, 70(12):1207-1213, 2018.
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Affiliation(s)
- Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences and Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Juan D Alfonzo
- Department of Microbiology, Ohio State Biochemistry Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA
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13
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Käser S, Glauser I, Rettig J, Schneider A. The pseudo-dimeric tyrosyl-tRNA synthetase of T. brucei aminoacylates cytosolic and mitochondrial tRNATyr and requires both monomeric units for activity. Mol Biochem Parasitol 2018; 221:52-55. [DOI: 10.1016/j.molbiopara.2018.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/15/2018] [Accepted: 03/21/2018] [Indexed: 12/14/2022]
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14
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Blewett NH, Maraia RJ. La involvement in tRNA and other RNA processing events including differences among yeast and other eukaryotes. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2018; 1861:361-372. [PMID: 29397330 DOI: 10.1016/j.bbagrm.2018.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/29/2017] [Accepted: 01/17/2018] [Indexed: 10/25/2022]
Abstract
The conserved nuclear RNA-binding factor known as La protein arose in an ancient eukaryote, phylogenetically associated with another eukaryotic hallmark, synthesis of tRNA by RNA polymerase III (RNAP III). Because 3'-oligo(U) is the sequence-specific signal for transcription termination by RNAP III as well as the high affinity binding site for La, the latter is linked to the intranuclear posttranscriptional processing of eukaryotic precursor-tRNAs. The pre-tRNA processing pathway must accommodate a variety of substrates that are destined for both common steps as well as tRNA-specific events. The order of intranuclear pre-tRNA processing steps is mediated in part by three activities derived from interaction with La protein: 3'-end protection from untimely decay by 3' exonucleases, nuclear retention and chaperone activity that helps prevent pre-tRNA misfolding and mischanneling into offline pathways. A focus of this perspective will be on differences between yeast and mammals in the subcellular partitioning of pre-tRNA intermediates and differential interactions with La. We review how this is most relevant to pre-tRNA splicing which occurs in the cytoplasm of yeasts but in nuclei of higher eukaryotes. Also divergent is La architecture, comprised of three RNA-binding domains in organisms in all examined branches of the eukaryal tree except yeast, which have lost the C-terminal RNA recognition motif-2α (RRM2α) domain. We also review emerging data that suggest mammalian La interacts with nuclear pre-tRNA splicing intermediates and may impact this branch of the tRNA maturation pathway. Finally, because La is involved in intranuclear tRNA biogenesis we review relevant aspects of tRNA-associated neurodegenerative diseases. This article is part of a Special Issue entitled: SI: Regulation of tRNA synthesis and modification in physiological conditions and disease edited by Dr. Boguta Magdalena.
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Affiliation(s)
- Nathan H Blewett
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Richard J Maraia
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA; Commissioned Corps, U.S. Public Health Service, Rockville, MD, USA.
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15
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Chatterjee K, Nostramo RT, Wan Y, Hopper AK. tRNA dynamics between the nucleus, cytoplasm and mitochondrial surface: Location, location, location. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2018; 1861:373-386. [PMID: 29191733 PMCID: PMC5882565 DOI: 10.1016/j.bbagrm.2017.11.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 11/19/2017] [Accepted: 11/23/2017] [Indexed: 01/20/2023]
Abstract
Although tRNAs participate in the essential function of protein translation in the cytoplasm, tRNA transcription and numerous processing steps occur in the nucleus. This subcellular separation between tRNA biogenesis and function requires that tRNAs be efficiently delivered to the cytoplasm in a step termed "primary tRNA nuclear export". Surprisingly, tRNA nuclear-cytoplasmic traffic is not unidirectional, but, rather, movement is bidirectional. Cytoplasmic tRNAs are imported back to the nucleus by the "tRNA retrograde nuclear import" step which is conserved from budding yeast to vertebrate cells and has been hijacked by viruses, such as HIV, for nuclear import of the viral reverse transcription complex in human cells. Under appropriate environmental conditions cytoplasmic tRNAs that have been imported into the nucleus return to the cytoplasm via the 3rd nuclear-cytoplasmic shuttling step termed "tRNA nuclear re-export", that again is conserved from budding yeast to vertebrate cells. We describe the 3 steps of tRNA nuclear-cytoplasmic movements and their regulation. There are multiple tRNA nuclear export and import pathways. The different tRNA nuclear exporters appear to possess substrate specificity leading to the tantalizing possibility that the cellular proteome may be regulated at the level of tRNA nuclear export. Moreover, in some organisms, such as budding yeast, the pre-tRNA splicing heterotetrameric endonuclease (SEN), which removes introns from pre-tRNAs, resides on the cytoplasmic surface of the mitochondria. Therefore, we also describe the localization of the SEN complex to mitochondria and splicing of pre-tRNA on mitochondria, which occurs prior to the participation of tRNAs in protein translation. This article is part of a Special Issue entitled: SI: Regulation of tRNA synthesis and modification in physiological conditions and disease edited by Dr. Boguta Magdalena.
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Affiliation(s)
- Kunal Chatterjee
- The Ohio State University Comprehensive Cancer Research Center, United States; Department of Molecular Genetics, The Ohio State University, United States; Center for RNA Biology, The Ohio State University, United States
| | - Regina T Nostramo
- Department of Molecular Genetics, The Ohio State University, United States; Center for RNA Biology, The Ohio State University, United States
| | - Yao Wan
- The Ohio State University Comprehensive Cancer Research Center, United States; Department of Molecular Genetics, The Ohio State University, United States; Center for RNA Biology, The Ohio State University, United States
| | - Anita K Hopper
- Department of Molecular Genetics, The Ohio State University, United States; Center for RNA Biology, The Ohio State University, United States.
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16
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Cherry PD, White LK, York K, Hesselberth JR. Genetic bypass of essential RNA repair enzymes in budding yeast. RNA (NEW YORK, N.Y.) 2018; 24:313-323. [PMID: 29212664 PMCID: PMC5824351 DOI: 10.1261/rna.061788.117] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 12/04/2017] [Indexed: 05/15/2023]
Abstract
RNA repair enzymes catalyze rejoining of an RNA molecule after cleavage of phosphodiester linkages. RNA repair in budding yeast is catalyzed by two separate enzymes that process tRNA exons during their splicing and HAC1 mRNA exons during activation of the unfolded protein response (UPR). The RNA ligase Trl1 joins 2',3'-cyclic phosphate and 5'-hydroxyl RNA fragments, creating a phosphodiester linkage with a 2'-phosphate at the junction. The 2'-phosphate is removed by the 2'-phosphotransferase Tpt1. We bypassed the essential functions of TRL1 and TPT1 in budding yeast by expressing "prespliced," intronless versions of the 10 normally intron-containing tRNAs, indicating this repair pathway does not have additional essential functions. Consistent with previous studies, expression of intronless tRNAs failed to rescue the growth of cells with deletions in components of the SEN complex, implying an additional essential role for the splicing endonuclease. The trl1Δ and tpt1Δ mutants accumulate tRNA and HAC1 splicing intermediates indicative of RNA repair defects and are hypersensitive to drugs that inhibit translation. Failure to induce the unfolded protein response in trl1Δ cells grown with tunicamycin is lethal owing to their inability to ligate HAC1 after its cleavage by Ire1. In contrast, tpt1Δ mutants grow in the presence of tunicamycin despite reduced accumulation of spliced HAC1 mRNA. We optimized a PCR-based method to detect RNA 2'-phosphate modifications and show they are present on ligated HAC1 mRNA. These RNA repair mutants enable new studies of the role of RNA repair in cellular physiology.
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Affiliation(s)
- Patrick D Cherry
- Department of Biochemistry and Molecular Genetics, Program in Molecular Biology, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Laura K White
- Department of Biochemistry and Molecular Genetics, Program in Molecular Biology, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Kerri York
- Department of Biochemistry and Molecular Genetics, Program in Molecular Biology, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Jay R Hesselberth
- Department of Biochemistry and Molecular Genetics, Program in Molecular Biology, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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17
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Kessler AC, Kulkarni SS, Paulines MJ, Rubio MAT, Limbach PA, Paris Z, Alfonzo JD. Retrograde nuclear transport from the cytoplasm is required for tRNA Tyr maturation in T. brucei. RNA Biol 2017; 15:528-536. [PMID: 28901827 PMCID: PMC6103694 DOI: 10.1080/15476286.2017.1377878] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 08/31/2017] [Accepted: 09/06/2017] [Indexed: 10/18/2022] Open
Abstract
Retrograde transport of tRNAs from the cytoplasm to the nucleus was first described in Saccharomyces cerevisiae and most recently in mammalian systems. Although the function of retrograde transport is not completely clear, it plays a role in the cellular response to changes in nutrient availability. Under low nutrient conditions tRNAs are sent from the cytoplasm to nucleus and presumably remain in storage there until nutrient levels improve. However, in S. cerevisiae tRNA retrograde transport is constitutive and occurs even when nutrient levels are adequate. Constitutive transport is important, at least, for the proper maturation of tRNAPhe, which undergoes cytoplasmic splicing, but requires the action of a nuclear modification enzyme that only acts on a spliced tRNA. A lingering question in retrograde tRNA transport is whether it is relegated to S. cerevisiae and multicellular eukaryotes or alternatively, is a pathway with deeper evolutionary roots. In the early branching eukaryote Trypanosoma brucei, tRNA splicing, like in yeast, occurs in the cytoplasm. In the present report, we have used a combination of cell fractionation and molecular approaches that show the presence of significant amounts of spliced tRNATyr in the nucleus of T. brucei. Notably, the modification enzyme tRNA-guanine transglycosylase (TGT) localizes to the nucleus and, as shown here, is not able to add queuosine (Q) to an intron-containing tRNA. We suggest that retrograde transport is partly the result of the differential intracellular localization of the splicing machinery (cytoplasmic) and a modification enzyme, TGT (nuclear). These findings expand the evolutionary distribution of retrograde transport mechanisms to include early diverging eukaryotes, while highlighting its importance for queuosine biosynthesis.
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Affiliation(s)
- Alan C. Kessler
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- The Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Sneha S. Kulkarni
- Institute of Parasitology, Biology Centre, South Bohemia, Czech Academy of Sciences and Faculty of Science, University of South Bohemia, České Budějovice, South Bohemia, Czech Republic
| | - Mellie J. Paulines
- Department of Chemistry, Rieveschl Laboratories for Mass Spectrometry, University of Cincinnati, Cincinnati, Ohio, USA
| | - Mary Anne T. Rubio
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- The Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Patrick A. Limbach
- Department of Chemistry, Rieveschl Laboratories for Mass Spectrometry, University of Cincinnati, Cincinnati, Ohio, USA
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, South Bohemia, Czech Academy of Sciences and Faculty of Science, University of South Bohemia, České Budějovice, South Bohemia, Czech Republic
| | - Juan D. Alfonzo
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA
- The Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
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18
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Kessler AC, Silveira d'Almeida G, Alfonzo JD. The role of intracellular compartmentalization on tRNA processing and modification. RNA Biol 2017; 15:554-566. [PMID: 28850002 DOI: 10.1080/15476286.2017.1371402] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
A signature of most eukaryotic cells is the presence of intricate membrane systems. Intracellular organization presumably evolved to provide order, and add layers for regulation of intracellular processes; compartmentalization also forcibly led to the appearance of sophisticated transport systems. With nucleus-encoded tRNAs, it led to the uncoupling of tRNA synthesis from many of the maturation steps it undergoes. It is now clear that tRNAs are actively transported across intracellular membranes and at any point, in any compartment, they can be post-transcriptionally modified; modification enzymes themselves may localize to any of the genome-containing compartments. In the following pages, we describe a number of well-known examples of how intracellular compartmentalization of tRNA processing and modification activities impact the function and fate of tRNAs. We raise the possibility that rates of intracellular transport may influence the level of modification and as such increase the diversity of differentially modified tRNAs in cells.
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Affiliation(s)
- Alan C Kessler
- a Department of Microbiology , The Ohio State University , Columbus , Ohio , USA.,b The Center for RNA Biology , The Ohio State University , Columbus , Ohio , USA
| | - Gabriel Silveira d'Almeida
- a Department of Microbiology , The Ohio State University , Columbus , Ohio , USA.,b The Center for RNA Biology , The Ohio State University , Columbus , Ohio , USA
| | - Juan D Alfonzo
- a Department of Microbiology , The Ohio State University , Columbus , Ohio , USA.,b The Center for RNA Biology , The Ohio State University , Columbus , Ohio , USA.,c The Ohio State Biochemistry Program , The Ohio State University , Columbus, Ohio , USA
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