1
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Loveland AB, Koh CS, Ganesan R, Jacobson A, Korostelev AA. Structural mechanism of angiogenin activation by the ribosome. Nature 2024; 630:769-776. [PMID: 38718836 DOI: 10.1038/s41586-024-07508-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 05/02/2024] [Indexed: 05/15/2024]
Abstract
Angiogenin, an RNase-A-family protein, promotes angiogenesis and has been implicated in cancer, neurodegenerative diseases and epigenetic inheritance1-10. After activation during cellular stress, angiogenin cleaves tRNAs at the anticodon loop, resulting in translation repression11-15. However, the catalytic activity of isolated angiogenin is very low, and the mechanisms of the enzyme activation and tRNA specificity have remained a puzzle3,16-23. Here we identify these mechanisms using biochemical assays and cryogenic electron microscopy (cryo-EM). Our study reveals that the cytosolic ribosome is the activator of angiogenin. A cryo-EM structure features angiogenin bound in the A site of the 80S ribosome. The C-terminal tail of angiogenin is rearranged by interactions with the ribosome to activate the RNase catalytic centre, making the enzyme several orders of magnitude more efficient in tRNA cleavage. Additional 80S-angiogenin structures capture how tRNA substrate is directed by the ribosome into angiogenin's active site, demonstrating that the ribosome acts as the specificity factor. Our findings therefore suggest that angiogenin is activated by ribosomes with a vacant A site, the abundance of which increases during cellular stress24-27. These results may facilitate the development of therapeutics to treat cancer and neurodegenerative diseases.
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Affiliation(s)
- Anna B Loveland
- RNA Therapeutics Institute, UMass Chan Medical School, Worcester, MA, USA.
| | - Cha San Koh
- RNA Therapeutics Institute, UMass Chan Medical School, Worcester, MA, USA
| | - Robin Ganesan
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
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2
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Pawar K, Kawamura T, Kirino Y. The tRNA Val half: A strong endogenous Toll-like receptor 7 ligand with a 5'-terminal universal sequence signature. Proc Natl Acad Sci U S A 2024; 121:e2319569121. [PMID: 38683985 PMCID: PMC11087793 DOI: 10.1073/pnas.2319569121] [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: 11/07/2023] [Accepted: 03/24/2024] [Indexed: 05/02/2024] Open
Abstract
Toll-like receptors (TLRs) are crucial components of the innate immune system. Endosomal TLR7 recognizes single-stranded RNAs, yet its endogenous ssRNA ligands are not fully understood. We previously showed that extracellular (ex-) 5'-half molecules of tRNAHisGUG (the 5'-tRNAHisGUG half) in extracellular vesicles (EVs) of human macrophages activate TLR7 when delivered into endosomes of recipient macrophages. Here, we fully explored immunostimulatory ex-5'-tRNA half molecules and identified the 5'-tRNAValCAC/AAC half, the most abundant tRNA-derived RNA in macrophage EVs, as another 5'-tRNA half molecule with strong TLR7 activation capacity. Levels of the ex-5'-tRNAValCAC/AAC half were highly up-regulated in macrophage EVs upon exposure to lipopolysaccharide and in the plasma of patients infected with Mycobacterium tuberculosis. The 5'-tRNAValCAC/AAC half-mediated activation of TLR7 effectively eradicated bacteria infected in macrophages. Mutation analyses of the 5'-tRNAValCAC/AAC half identified the terminal GUUU sequence as a determinant for TLR7 activation. We confirmed that GUUU is the optimal ratio of guanosine and uridine for TLR7 activation; microRNAs or other RNAs with the terminal GUUU motif can indeed stimulate TLR7, establishing the motif as a universal signature for TLR7 activation. These results advance our understanding of endogenous ssRNA ligands of TLR7 and offer insights into diverse TLR7-involved pathologies and their therapeutic strategies.
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Affiliation(s)
- Kamlesh Pawar
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA19107
- Department of Life Sciences, School of Natural Science, Shiv Nadar Institution of Eminence Deemed to be University, Delhi National Capital Region, Greater Noida201314, India
| | - Takuya Kawamura
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA19107
| | - Yohei Kirino
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA19107
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3
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Ahammed KS, van Hoof A. Fungi of the order Mucorales express a "sealing-only" tRNA ligase. RNA (NEW YORK, N.Y.) 2024; 30:354-366. [PMID: 38307611 PMCID: PMC10946435 DOI: 10.1261/rna.079957.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 01/20/2024] [Indexed: 02/04/2024]
Abstract
Some eukaryotic pre-tRNAs contain an intron that is removed by a dedicated set of enzymes. Intron-containing pre-tRNAs are cleaved by tRNA splicing endonuclease, followed by ligation of the two exons and release of the intron. Fungi use a "heal and seal" pathway that requires three distinct catalytic domains of the tRNA ligase enzyme, Trl1. In contrast, humans use a "direct ligation" pathway carried out by RTCB, an enzyme completely unrelated to Trl1. Because of these mechanistic differences, Trl1 has been proposed as a promising drug target for fungal infections. To validate Trl1 as a broad-spectrum drug target, we show that fungi from three different phyla contain Trl1 orthologs with all three domains. This includes the major invasive human fungal pathogens, and these proteins can each functionally replace yeast Trl1. In contrast, species from the order Mucorales, including the pathogens Rhizopus arrhizus and Mucor circinelloides, have an atypical Trl1 that contains the sealing domain but lacks both healing domains. Although these species contain fewer tRNA introns than other pathogenic fungi, they still require splicing to decode three of the 61 sense codons. These sealing-only Trl1 orthologs can functionally complement defects in the corresponding domain of yeast Trl1 and use a conserved catalytic lysine residue. We conclude that Mucorales use a sealing-only enzyme together with unidentified nonorthologous healing enzymes for their heal and seal pathway. This implies that drugs that target the sealing activity are more likely to be broader-spectrum antifungals than drugs that target the healing domains.
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Affiliation(s)
- Khondakar Sayef Ahammed
- Department of Microbiology and Molecular Genetics, UT MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, University of Texas Health Science Center, Houston, Texas 77030, USA
| | - Ambro van Hoof
- Department of Microbiology and Molecular Genetics, UT MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, University of Texas Health Science Center, Houston, Texas 77030, USA
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4
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Gumas J, Kawamura T, Shigematsu M, Kirino Y. Immunostimulatory short non-coding RNAs in the circulation of patients with tuberculosis infection. MOLECULAR THERAPY. NUCLEIC ACIDS 2024; 35:102156. [PMID: 38481936 PMCID: PMC10933579 DOI: 10.1016/j.omtn.2024.102156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 02/14/2024] [Indexed: 03/20/2024]
Abstract
Mycobacterium tuberculosis (Mtb) infection is among the world's deadliest infectious diseases. Developing effective treatments and biomarkers for tuberculosis requires a deeper understanding of its pathobiology and host responses. Here, we report a comprehensive characterization of circulating short non-coding RNAs (sncRNAs) in plasma samples from Mtb-infected patients. We achieved this by pre-treating plasma RNAs with T4 polynucleotide kinase to convert all RNA ends to those compatible with sncRNA sequencing. We discovered a global and drastic upregulation of plasma sncRNAs in Mtb-infected patients, with tRNA-derived sncRNAs representing the most dramatically elevated class. Most of these tRNA-derived sncRNAs originated from a limited subset of tRNAs, specifically from three tRNA isoacceptors, and exhibited skewed patterns to 5'-derived fragments, such as 5' halves, 5' tRNA fragments (tRFs), and internal tRFs (i-tRFs) from the 5' regions. Further, Mtb-infected patients displayed markedly upregulated and distinct profiles of both rRNA- and mRNA-derived sncRNAs. Some of these sncRNAs, which are abundant and specific to Mtb-infected patients, robustly activated human macrophages via Toll-like receptor 7 and induced cytokine production. This drastic accumulation of circulating, immunostimulatory sncRNAs in the plasma of Mtb-infected patients offers insights into the sncRNA-driven aspects of host immune response against infectious diseases and suggests a pool of potential therapeutic targets and biomarkers.
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Affiliation(s)
- Justin Gumas
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Takuya Kawamura
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Megumi Shigematsu
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Yohei Kirino
- Computational Medicine Center, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
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5
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Tosar JP, Castellano M, Costa B, Cayota A. Small RNA structural biochemistry in a post-sequencing era. Nat Protoc 2024; 19:595-602. [PMID: 38057624 DOI: 10.1038/s41596-023-00936-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 08/25/2023] [Indexed: 12/08/2023]
Abstract
High-throughput sequencing has had an enormous impact on small RNA research during the past decade. However, sequencing only offers a one-dimensional view of the transcriptome and is often highly biased. Additionally, the 'sequence, map and annotate' approach, used widely in small RNA research, can lead to flawed interpretations of the data, lacking biological plausibility, due in part to database issues. Even in the absence of technical biases, the loss of three-dimensional information is a major limitation to understanding RNA stability, turnover and function. For example, noncoding RNA-derived fragments seem to exist mainly as dimers, tetramers or as nicked forms of their parental RNAs, contrary to widespread assumptions. In this perspective, we will discuss main sources of bias during small RNA-sequencing, present several useful bias-reducing strategies and provide guidance on the interpretation of small RNA-sequencing results, with emphasis on RNA fragmentomics. As sequencing offers a one-dimensional projection of a four-dimensional reality, prior structure-level knowledge is often needed to make sense of the data. Consequently, while less-biased sequencing methods are welcomed, integration of orthologous experimental techniques is also strongly recommended.
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Affiliation(s)
- Juan Pablo Tosar
- Functional Genomics Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay.
- Analytical Biochemistry Unit, Center for Nuclear Research, School of Science, Universidad de la República, Montevideo, Uruguay.
| | - Mauricio Castellano
- Functional Genomics Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Biochemistry Department, School of Science, Universidad de la República, Montevideo, Uruguay
| | - Bruno Costa
- Functional Genomics Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Analytical Biochemistry Unit, Center for Nuclear Research, School of Science, Universidad de la República, Montevideo, Uruguay
| | - Alfonso Cayota
- Functional Genomics Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay
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6
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Zhang J. Recognition of the tRNA structure: Everything everywhere but not all at once. Cell Chem Biol 2024; 31:36-52. [PMID: 38159570 PMCID: PMC10843564 DOI: 10.1016/j.chembiol.2023.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 12/02/2023] [Accepted: 12/11/2023] [Indexed: 01/03/2024]
Abstract
tRNAs are among the most abundant and essential biomolecules in cells. These spontaneously folding, extensively structured yet conformationally flexible anionic polymers literally bridge the worlds of RNAs and proteins, and serve as Rosetta stones that decipher and interpret the genetic code. Their ubiquitous presence, functional irreplaceability, and privileged access to cellular compartments and ribosomes render them prime targets for both endogenous regulation and exogenous manipulation. There is essentially no part of the tRNA that is not touched by another interaction partner, either as programmed or imposed by an external adversary. Recent progresses in genetic, biochemical, and structural analyses of the tRNA interactome produced a wealth of new knowledge into their interaction networks, regulatory functions, and molecular interfaces. In this review, I describe and illustrate the general principles of tRNA recognition by proteins and other RNAs, and discuss the underlying molecular mechanisms that deliver affinity, specificity, and functional competency.
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Affiliation(s)
- Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
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7
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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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8
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Ahammed KS, van Hoof A. Fungi of the order Mucorales express a "sealing-only" tRNA ligase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.16.567474. [PMID: 38014270 PMCID: PMC10680797 DOI: 10.1101/2023.11.16.567474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Some eukaryotic pre-tRNAs contain an intron that is removed by a dedicated set of enzymes. Intron-containing pre-tRNAs are cleaved by tRNA splicing endonuclease (TSEN), followed by ligation of the two exons and release of the intron. Fungi use a "heal and seal" pathway that requires three distinct catalytic domains of the tRNA ligase enzyme, Trl1. In contrast, humans use a "direct ligation" pathway carried out by RTCB, an enzyme completely unrelated to Trl1. Because of these mechanistic differences, Trl1 has been proposed as a promising drug target for fungal infections. To validate Trl1 as a broad-spectrum drug target, we show that fungi from three different phyla contain Trl1 orthologs with all three domains. This includes the major invasive human fungal pathogens, and these proteins each can functionally replace yeast Trl1. In contrast, species from the order Mucorales, including the pathogens Rhizopus arrhizus and Mucor circinelloides, contain an atypical Trl1 that contains the sealing domain, but lack both healing domains. Although these species contain fewer tRNA introns than other pathogenic fungi, they still require splicing to decode three of the 61 sense codons. These sealing-only Trl1 orthologs can functionally complement defects in the corresponding domain of yeast Trl1 and use a conserved catalytic lysine residue. We conclude that Mucorales use a sealing-only enzyme together with unidentified non-orthologous healing enzymes for their heal and seal pathway. This implies that drugs that target the sealing activity are more likely to be broader-spectrum antifungals than drugs that target the healing domains.
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Affiliation(s)
- Khondakar Sayef Ahammed
- Department of Microbiology and Molecular Genetics. UT MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences. University of Texas Health Science Center at Houston
| | - Ambro van Hoof
- Department of Microbiology and Molecular Genetics. UT MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences. University of Texas Health Science Center at Houston
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9
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Kuhle B, Chen Q, Schimmel P. tRNA renovatio: Rebirth through fragmentation. Mol Cell 2023; 83:3953-3971. [PMID: 37802077 PMCID: PMC10841463 DOI: 10.1016/j.molcel.2023.09.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/15/2023] [Accepted: 09/12/2023] [Indexed: 10/08/2023]
Abstract
tRNA function is based on unique structures that enable mRNA decoding using anticodon trinucleotides. These structures interact with specific aminoacyl-tRNA synthetases and ribosomes using 3D shape and sequence signatures. Beyond translation, tRNAs serve as versatile signaling molecules interacting with other RNAs and proteins. Through evolutionary processes, tRNA fragmentation emerges as not merely random degradation but an act of recreation, generating specific shorter molecules called tRNA-derived small RNAs (tsRNAs). These tsRNAs exploit their linear sequences and newly arranged 3D structures for unexpected biological functions, epitomizing the tRNA "renovatio" (from Latin, meaning renewal, renovation, and rebirth). Emerging methods to uncover full tRNA/tsRNA sequences and modifications, combined with techniques to study RNA structures and to integrate AI-powered predictions, will enable comprehensive investigations of tRNA fragmentation products and new interaction potentials in relation to their biological functions. We anticipate that these directions will herald a new era for understanding biological complexity and advancing pharmaceutical engineering.
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Affiliation(s)
- Bernhard Kuhle
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA; Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Qi Chen
- Molecular Medicine Program, Department of Human Genetics, and Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Paul Schimmel
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA.
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10
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Akiyama Y, Ivanov P. tRNA-derived RNAs: Biogenesis and roles in translational control. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1805. [PMID: 37406666 PMCID: PMC10766869 DOI: 10.1002/wrna.1805] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 05/17/2023] [Accepted: 06/06/2023] [Indexed: 07/07/2023]
Abstract
Transfer RNA (tRNA)-derived RNAs (tDRs) are a class of small non-coding RNAs that play important roles in different aspects of gene expression. These ubiquitous and heterogenous RNAs, which vary across different species and cell types, are proposed to regulate various biological processes. In this review, we will discuss aspects of their biogenesis, and specifically, their contribution into translational control. We will summarize diverse roles of tDRs and the molecular mechanisms underlying their functions in the regulation of protein synthesis and their impact on related events such as stress-induced translational reprogramming. This article is categorized under: RNA Processing > Processing of Small RNAs Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs Regulatory RNAs/RNAi/Riboswitches > Biogenesis of Effector Small RNAs.
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Affiliation(s)
- Yasutoshi Akiyama
- Laboratory of Oncology, Pharmacy Practice and Sciences, Tohoku University Graduate School of Pharmaceutical Sciences, Sendai, Japan
| | - Pavel Ivanov
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
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11
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Chen Q, Zhou T. Emerging functional principles of tRNA-derived small RNAs and other regulatory small RNAs. J Biol Chem 2023; 299:105225. [PMID: 37673341 PMCID: PMC10562873 DOI: 10.1016/j.jbc.2023.105225] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 08/22/2023] [Accepted: 08/28/2023] [Indexed: 09/08/2023] Open
Abstract
Recent advancements in small RNA sequencing have unveiled a previously hidden world of regulatory small noncoding RNAs (sncRNAs) that extend beyond the well-studied small interfering RNAs, microRNAs, and piwi-interacting RNAs. This exploration, starting with tRNA-derived small RNAs, has led to the discovery of a diverse universe of sncRNAs derived from various longer structured RNAs such as rRNAs, small nucleolar RNAs, small nuclear RNAs, Y RNAs, and vault RNAs, with exciting uncharted functional possibilities. In this perspective, we discuss the emerging functional principles of sncRNAs beyond the well-known RNAi-like mechanisms, focusing on those that operate independent of linear sequence complementarity but rather function in an aptamer-like fashion. Aptamers use 3D structure for specific interactions with ligands and are modulated by RNA modifications and subcellular environments. Given that aptamer-like sncRNA functions are widespread and present in species lacking RNAi, they may represent an ancient functional principle that predates RNAi. We propose a rethinking of the origin of RNAi and its relationship with these aptamer-like functions in sncRNAs and how these complementary mechanisms shape biological processes. Lastly, the aptamer-like function of sncRNAs highlights the need for caution in using small RNA mimics in research and therapeutics, as their specificity is not restricted solely to linear sequence.
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Affiliation(s)
- Qi Chen
- Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, Utah, USA; Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, Utah, USA; Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, USA.
| | - Tong Zhou
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada, USA.
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12
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Biela A, Hammermeister A, Kaczmarczyk I, Walczak M, Koziej L, Lin TY, Glatt S. The diverse structural modes of tRNA binding and recognition. J Biol Chem 2023; 299:104966. [PMID: 37380076 PMCID: PMC10424219 DOI: 10.1016/j.jbc.2023.104966] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 06/30/2023] Open
Abstract
tRNAs are short noncoding RNAs responsible for decoding mRNA codon triplets, delivering correct amino acids to the ribosome, and mediating polypeptide chain formation. Due to their key roles during translation, tRNAs have a highly conserved shape and large sets of tRNAs are present in all living organisms. Regardless of sequence variability, all tRNAs fold into a relatively rigid three-dimensional L-shaped structure. The conserved tertiary organization of canonical tRNA arises through the formation of two orthogonal helices, consisting of the acceptor and anticodon domains. Both elements fold independently to stabilize the overall structure of tRNAs through intramolecular interactions between the D- and T-arm. During tRNA maturation, different modifying enzymes posttranscriptionally attach chemical groups to specific nucleotides, which not only affect translation elongation rates but also restrict local folding processes and confer local flexibility when required. The characteristic structural features of tRNAs are also employed by various maturation factors and modification enzymes to assure the selection, recognition, and positioning of specific sites within the substrate tRNAs. The cellular functional repertoire of tRNAs continues to extend well beyond their role in translation, partly, due to the expanding pool of tRNA-derived fragments. Here, we aim to summarize the most recent developments in the field to understand how three-dimensional structure affects the canonical and noncanonical functions of tRNA.
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Affiliation(s)
- Anna Biela
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | | | - Igor Kaczmarczyk
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland; Doctoral School of Exact and Natural Sciences, Jagiellonian University, Krakow, Poland
| | - Marta Walczak
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland; Doctoral School of Exact and Natural Sciences, Jagiellonian University, Krakow, Poland
| | - Lukasz Koziej
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Ting-Yu Lin
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland.
| | - Sebastian Glatt
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland.
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13
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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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14
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Scacchetti A, Shields EJ, Trigg NA, Wilusz JE, Conine CC, Bonasio R. A ligation-independent sequencing method reveals tRNA-derived RNAs with blocked 3' termini. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.06.543899. [PMID: 37333231 PMCID: PMC10274639 DOI: 10.1101/2023.06.06.543899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Despite the numerous sequencing methods available, the vast diversity in size and chemical modifications of RNA molecules makes the capture of the full spectrum of cellular RNAs a difficult task. By combining quasi-random hexamer priming with a custom template switching strategy, we developed a method to construct sequencing libraries from RNA molecules of any length and with any type of 3' terminal modification, allowing the sequencing and analysis of virtually all RNA species. Ligation-independent detection of all types of RNA (LIDAR) is a simple, effective tool to comprehensively characterize changes in small non-coding RNAs and mRNAs simultaneously, with performance comparable to separate dedicated methods. With LIDAR, we comprehensively characterized the coding and non-coding transcriptome of mouse embryonic stem cells, neural progenitor cells, and sperm. LIDAR detected a much larger variety of tRNA-derived RNAs (tDRs) compared to traditional ligation-dependent sequencing methods, and uncovered the presence of tDRs with blocked 3' ends that had previously escaped detection. Our findings highlight the potential of LIDAR to systematically detect all RNAs in a sample and uncover new RNA species with potential regulatory functions.
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Affiliation(s)
- Alessandro Scacchetti
- Epigenetics Institute and Department of Cell and Developmental Biology; University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Emily J. Shields
- Epigenetics Institute and Department of Cell and Developmental Biology; University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
- Department of Urology and Institute of Neuropathology, Medical Center–University of Freiburg, 79106 Freiburg, Germany
| | - Natalie A. Trigg
- Departments of Genetics and Pediatrics - Penn Epigenetics Institute, Institute of Regenerative Medicine, and Center for Research on Reproduction and Women’s Health, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
- Division of Neonatology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jeremy E. Wilusz
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Therapeutic Innovation Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Colin C. Conine
- Departments of Genetics and Pediatrics - Penn Epigenetics Institute, Institute of Regenerative Medicine, and Center for Research on Reproduction and Women’s Health, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
- Division of Neonatology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Roberto Bonasio
- Epigenetics Institute and Department of Cell and Developmental Biology; University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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