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Tijaro-Bulla S, Nyandwi SP, Cui H. Physiological and engineered tRNA aminoacylation. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1789. [PMID: 37042417 DOI: 10.1002/wrna.1789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/11/2023] [Accepted: 03/21/2023] [Indexed: 04/13/2023]
Abstract
Aminoacyl-tRNA synthetases form the protein family that controls the interpretation of the genetic code, with tRNA aminoacylation being the key chemical step during which an amino acid is assigned to a corresponding sequence of nucleic acids. In consequence, aminoacyl-tRNA synthetases have been studied in their physiological context, in disease states, and as tools for synthetic biology to enable the expansion of the genetic code. Here, we review the fundamentals of aminoacyl-tRNA synthetase biology and classification, with a focus on mammalian cytoplasmic enzymes. We compile evidence that the localization of aminoacyl-tRNA synthetases can be critical in health and disease. In addition, we discuss evidence from synthetic biology which made use of the importance of subcellular localization for efficient manipulation of the protein synthesis machinery. This article is categorized under: RNA Processing Translation > Translation Regulation RNA Processing > tRNA Processing RNA Export and Localization > RNA Localization.
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Affiliation(s)
| | | | - Haissi Cui
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
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Site-Specific Fluorescent Labeling of RNA Interior Positions. Molecules 2021; 26:molecules26051341. [PMID: 33802273 PMCID: PMC7959133 DOI: 10.3390/molecules26051341] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 02/08/2023] Open
Abstract
The introduction of fluorophores into RNA for both in vitro and in cellulo studies of RNA function and cellular distribution is a subject of great current interest. Here I briefly review methods, some well-established and others newly developed, which have been successfully exploited to site-specifically fluorescently label interior positions of RNAs, as a guide to investigators seeking to apply this approach to their studies. Most of these methods can be applied directly to intact RNAs, including (1) the exploitation of natural posttranslational modifications, (2) the repurposing of enzymatic transferase reactions, and (3) the nucleic acid-assisted labeling of intact RNAs. In addition, several methods are described in which specifically labeled RNAs are prepared de novo.
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Alroy I, Mansour W, Klepfish M, Sheinberger Y. Expanding small-molecule target space to mRNA translation regulation. Drug Discov Today 2020; 26:786-793. [PMID: 33296694 DOI: 10.1016/j.drudis.2020.11.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/26/2020] [Accepted: 11/12/2020] [Indexed: 01/05/2023]
Abstract
Multiple layers of regulation are in place on mRNA translation to ensure that cells respond in a fast manner to environmental cues in a tissue-specific and mRNA-selective manner. Here, we discuss mRNA translation regulatory mechanisms and potential drug-intervention targets. Taking on a new scientific rational of translation regulation and consequently a new target space, we have developed a unique discovery platform that is able to identify selective small molecule drugs that affect translation of specific proteins. This approach has enabled targeting of proteins that have been considered undruggable. Our discovery platform was repeatedly utilized to identify compounds in multiple therapeutic programs, including fibrosis, oncology, anti-virals and Huntington's disease. In fibrosis, the lead compound ANI-21 has demonstrated a tissue-specific effect in lowering the translation of Collagen-I and superior efficacy over best standard of care, in both cell and animal models, mediated by a novel mechanism of action. This program is expected to enter clinical studies within 12-18 months.
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Affiliation(s)
- Iris Alroy
- Anima Biotech, Bernardsville, NJ 07924, USA.
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Koltun B, Ironi S, Gershoni-Emek N, Barrera I, Hleihil M, Nanguneri S, Sasmal R, Agasti SS, Nair D, Rosenblum K. Measuring mRNA translation in neuronal processes and somata by tRNA-FRET. Nucleic Acids Res 2020; 48:e32. [PMID: 31974573 PMCID: PMC7102941 DOI: 10.1093/nar/gkaa042] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 12/04/2019] [Accepted: 01/15/2020] [Indexed: 01/12/2023] Open
Abstract
In neurons, the specific spatial and temporal localization of protein synthesis is of great importance for function and survival. Here, we visualized tRNA and protein synthesis events in fixed and live mouse primary cortical culture using fluorescently-labeled tRNAs. We were able to characterize the distribution and transport of tRNAs in different neuronal sub-compartments and to study their association with the ribosome. We found that tRNA mobility in neural processes is lower than in somata and corresponds to patterns of slow transport mechanisms, and that larger tRNA puncta co-localize with translational machinery components and are likely the functional fraction. Furthermore, chemical induction of long-term potentiation (LTP) in culture revealed up-regulation of mRNA translation with a similar effect in dendrites and somata, which appeared to be GluR-dependent 6 h post-activation. Importantly, measurement of protein synthesis in neurons with high resolutions offers new insights into neuronal function in health and disease states.
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Affiliation(s)
- Bella Koltun
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Sivan Ironi
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | | | - Iliana Barrera
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Mohammad Hleihil
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | | | - Ranjan Sasmal
- New Chemistry Unit and Chemistry & Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bangalore, Karnataka, India
| | - Sarit S Agasti
- New Chemistry Unit and Chemistry & Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bangalore, Karnataka, India
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
| | - Kobi Rosenblum
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel.,Center for Gene Manipulation in the Brain, University of Haifa, Haifa, Israel
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Dhakal R, Tong C, Anderson S, Kashina A, Cooperman B, Bau H. Dynamics of intracellular stress-induced tRNA trafficking. Nucleic Acids Res 2019; 47:2002-2010. [PMID: 30496477 PMCID: PMC6393242 DOI: 10.1093/nar/gky1208] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 11/09/2018] [Accepted: 11/20/2018] [Indexed: 01/15/2023] Open
Abstract
Stress is known to induce retrograde tRNA translocation from the cytoplasm to the nucleus but translocation kinetics and tRNA-spatial distribution have not been characterized previously. We microinject fluorescently-labeled tRNA into living cells and use confocal microscopy to image tRNA spatial distribution in single cells at various levels of starvation and to determine translocation rate constants. Retrograde tRNA translocation occurs reversibly, within minutes after nutrition depletion of the extracellular medium. Such nutritional starvation leads to down-regulation of tRNA nuclear import and nearly complete curtailment of its nuclear export. Nuclear tRNA accumulation is suppressed in cells treated with the translation inhibitor puromycin, but is enhanced in cells treated with the microtubule inhibitor nocodazole. tRNA in the cytoplasm exhibits distinct spatial distribution inconsistent with diffusion, implying that such distribution is actively maintained. We propose that tRNA biological complexes and/or cytoplasmic electric fields are the likely regulators of cytoplasmic tRNA spatial distribution.
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Affiliation(s)
- Rabin Dhakal
- Department of Mechanical Engineering and Applied mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Chunyi Tong
- Department of Mechanical Engineering and Applied mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sean Anderson
- Department of Mechanical Engineering and Applied mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anna S Kashina
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Barry Cooperman
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19014, USA
| | - Haim H Bau
- Department of Mechanical Engineering and Applied mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
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