1
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Zhang Y, Xu Z, Xiao Y, Jiang H, Zuo X, Li X, Fang X. Structural mechanisms for binding and activation of a contact-quenched fluorophore by RhoBAST. Nat Commun 2024; 15:4206. [PMID: 38760339 PMCID: PMC11101630 DOI: 10.1038/s41467-024-48478-9] [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: 10/02/2023] [Accepted: 04/29/2024] [Indexed: 05/19/2024] Open
Abstract
The fluorescent light-up aptamer RhoBAST, which binds and activates the fluorophore-quencher conjugate tetramethylrhodamine-dinitroaniline with high affinity, super high brightness, remarkable photostability, and fast exchange kinetics, exhibits excellent performance in super-resolution RNA imaging. Here we determine the co-crystal structure of RhoBAST in complex with tetramethylrhodamine-dinitroaniline to elucidate the molecular basis for ligand binding and fluorescence activation. The structure exhibits an asymmetric "A"-like architecture for RhoBAST with a semi-open binding pocket harboring the xanthene of tetramethylrhodamine at the tip, while the dinitroaniline quencher stacks over the phenyl of tetramethylrhodamine instead of being fully released. Molecular dynamics simulations show highly heterogeneous conformational ensembles with the contact-but-unstacked fluorophore-quencher conformation for both free and bound tetramethylrhodamine-dinitroaniline being predominant. The simulations also show that, upon RNA binding, the fraction of xanthene-dinitroaniline stacked conformation significantly decreases in free tetramethylrhodamine-dinitroaniline. This highlights the importance of releasing dinitroaniline from xanthene tetramethylrhodamine to unquench the RhoBAST-tetramethylrhodamine-dinitroaniline complex. Using SAXS and ITC, we characterized the magnesium dependency of the folding and binding mode of RhoBAST in solution and indicated its strong structural robustness. The structures and binding modes of relevant fluorescent light-up aptamers are compared, providing mechanistic insights for rational design and optimization of this important fluorescent light-up aptamer-ligand system.
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Affiliation(s)
- Yufan Zhang
- Key Laboratory of RNA Science and Engineering, Institute of Biophysics Chinese Academy of Sciences, Beijing, China
| | - Zhonghe Xu
- Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yu Xiao
- Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China
| | - Haodong Jiang
- Institute of Zoology, Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China
| | - Xiaobing Zuo
- X-ray Science Division, Argonne National Laboratory, Lemont, IL, USA
| | - Xing Li
- Institute of Zoology, Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China.
| | - Xianyang Fang
- Key Laboratory of RNA Science and Engineering, Institute of Biophysics Chinese Academy of Sciences, Beijing, China.
- Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China.
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2
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Hołyst R, Bubak G, Kalwarczyk T, Kwapiszewska K, Michalski J, Pilz M. Living Cell as a Self-Synchronized Chemical Reactor. J Phys Chem Lett 2024; 15:3559-3570. [PMID: 38526849 PMCID: PMC11000238 DOI: 10.1021/acs.jpclett.4c00190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/21/2024] [Accepted: 03/21/2024] [Indexed: 03/27/2024]
Abstract
Thermal fluctuations power all processes inside living cells. Therefore, these processes are inherently random. However, myriad multistep chemical reactions act in concerto inside a cell, finally leading to this chemical reactor's self-replication. We speculate that an underlying mechanism in nature must exist that allows all of these reactions to synchronize at multiple time and length scales, overcoming in this way the random nature of any single process in a cell. This Perspective discusses what type of research is needed to understand this undiscovered synchronization law.
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Affiliation(s)
- Robert Hołyst
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Grzegorz Bubak
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Tomasz Kalwarczyk
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Karina Kwapiszewska
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Jarosław Michalski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Marta Pilz
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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3
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Chen W, Zhao X, Yang N, Li X. Single mRNA Imaging with Fluorogenic RNA Aptamers and Small-molecule Fluorophores. Angew Chem Int Ed Engl 2023; 62:e202209813. [PMID: 36420710 DOI: 10.1002/anie.202209813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/07/2022] [Accepted: 11/24/2022] [Indexed: 11/25/2022]
Abstract
Messenger RNA (mRNA) is the fundamental information transfer system in the cell. Tracking single mRNA from transcription to degradation with fluorescent probes provides spatiotemporal information in cells about how the genetic information is transferred from DNA to proteins. The traditional single mRNA imaging approach utilizes RNA hairpins (e.g. MS2) and tethered fluorescent protein as probes. As an exciting alternative, RNA aptamers: small-molecule fluorophores (SFs) systems have emerged as novel single mRNA imaging probes since 2019, exhibiting several advantages including fluorogenic ability and minimal perturbation. This review summarizes all five reported RNA aptamers: SFs systems for single mRNA imaging in living cells so far. It also discusses the challenges and provides prospects for single mRNA imaging applications. This review is expected to inspire researchers to develop RNA aptamers: SFs systems for studying gene expression at single-molecule resolution in cells.
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Affiliation(s)
- Wei Chen
- Institute of Cytology and Genetics, the Hengyang Key Laboratory of Cellular Stress Biology, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China.,Beijing Institutes of Life Science, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Science, Beijing, 100101, China
| | - Xiaoying Zhao
- College of Chemistry and Materials Engineering, Beijing Technology and Business University, Beijing, 100048, China
| | - Nanyang Yang
- Institute of Cytology and Genetics, the Hengyang Key Laboratory of Cellular Stress Biology, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
| | - Xing Li
- Beijing Institutes of Life Science, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Science, Beijing, 100101, China
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4
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Lee BH, Bang S, Lee S, Jeon NL, Park HY. Dynamics of axonal β-actin mRNA in live hippocampal neurons. Traffic 2022; 23:496-505. [PMID: 36054788 PMCID: PMC9804286 DOI: 10.1111/tra.12865] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 07/09/2022] [Accepted: 08/10/2022] [Indexed: 01/05/2023]
Abstract
Localization of mRNA facilitates spatiotemporally controlled protein expression in neurons. In axons, mRNA transport followed by local protein synthesis plays a critical role in axonal growth and guidance. However, it is not yet clearly understood how mRNA is transported to axonal subcellular sites and what regulates axonal mRNA localization. Using a transgenic mouse model in which endogenous β-actin mRNA is fluorescently labeled, we investigated β-actin mRNA movement in axons of hippocampal neurons. We cultured neurons in microfluidic devices to separate axons from dendrites and performed single-particle tracking of axonal β-actin mRNA. Compared with dendritic β-actin mRNA, axonal β-actin mRNA showed less directed motion and exhibited mostly subdiffusive motion, especially near filopodia and boutons in mature dissociated hippocampal neurons. We found that axonal β-actin mRNA was likely to colocalize with actin patches (APs), regions that have a high density of filamentous actin (F-actin) and are known to have a role in branch initiation. Moreover, simultaneous imaging of F-actin and axonal β-actin mRNA in live neurons revealed that moving β-actin mRNA tended to be docked in the APs. Our findings reveal that axonal β-actin mRNA localization is facilitated by actin networks and suggest that localized β-actin mRNA plays a potential role in axon branch formation.
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Affiliation(s)
- Byung Hun Lee
- Department of Physics and AstronomySeoul National UniversitySeoulRepublic of Korea
| | - Seokyoung Bang
- Department of Mechanical EngineeringSeoul National UniversitySeoulRepublic of Korea,Department of Medical BiotechnologyDongguk UniversityGoyangRepublic of Korea
| | - Seung‐Ryeol Lee
- Department of Mechanical EngineeringSeoul National UniversitySeoulRepublic of Korea
| | - Noo Li Jeon
- Department of Mechanical EngineeringSeoul National UniversitySeoulRepublic of Korea
| | - Hye Yoon Park
- Department of Physics and AstronomySeoul National UniversitySeoulRepublic of Korea,The Institute of Applied PhysicsSeoul National UniversitySeoulRepublic of Korea,Department of Electrical and Computer EngineeringUniversity of MinnesotaMinneapolisMinnesotaUSA
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5
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Sun P, Zou W. Research progress of live-cell RNA imaging techniques. Zhejiang Da Xue Xue Bao Yi Xue Ban 2022; 51:362-372. [PMID: 36207827 PMCID: PMC9511491 DOI: 10.3724/zdxbyxb-2022-0017] [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] [Received: 01/23/2022] [Accepted: 04/12/2022] [Indexed: 06/16/2023]
Abstract
RNA molecules play diverse roles in many physiological and pathological processes as they interact with various nucleic acids and proteins. The various biological processes of RNA are highly dynamic. Tracking RNA dynamics in living cells is crucial for a better understanding of the spatiotemporal control of gene expression and the regulatory roles of RNA. Genetically encoded RNA-tagging systems include MS2/MCP, PP7/PCP, boxB/λN22 and CRISPR-Cas. The MS2/MCP system is the most widely applied, and it has the advantages of stable binding and high signal-to-noise ratio, while the realization of RNA imaging requires gene editing of the target RNA, which may change the characteristics of the target RNA. Recently developed CRISPR-dCas13 system does not require RNA modification, but the uncertainty in CRISPR RNA (crRNA) efficiency and low signal-to-noise ratio are its limitations. Fluorescent dye-based RNA-tagging systems include molecular beacons and fluorophore-binding aptamers. The molecular beacons have high specificity and high signal-to-noise ratio; Mango and Peppers outperform the other RNA-tagging system in signal-to-noise, but they also need gene editing. Live-cell RNA imaging allows us to visualize critical steps of RNA activities, including transcription, splicing, transport, translation (for message RNA only) and subcellular localization. It will contribute to studying biological processes such as cell differentiation and the transcriptional regulation mechanism when cells adapt to the external environment, and it improves our understanding of the pathogenic mechanism of various diseases caused by abnormal RNA behavior and helps to find potential therapeutic targets. This review provides an overview of current progress of live-cell RNA imaging techniques and highlights their major strengths and limitations.
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Affiliation(s)
- Pingping Sun
- 1. The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, Zhejiang Province, China
- 2. Institute of Translational Medicine, Zhejiang University, Hangzhou 310058, China
| | - Wei Zou
- 1. The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, Zhejiang Province, China
- 2. Institute of Translational Medicine, Zhejiang University, Hangzhou 310058, China
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6
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Recent Advances in Fluorescence Recovery after Photobleaching for Decoupling Transport and Kinetics of Biomacromolecules in Cellular Physiology. Polymers (Basel) 2022; 14:polym14091913. [PMID: 35567083 PMCID: PMC9105003 DOI: 10.3390/polym14091913] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 12/16/2022] Open
Abstract
Among the new molecular tools available to scientists and engineers, some of the most useful include fluorescently tagged biomolecules. Tools, such as green fluorescence protein (GFP), have been applied to perform semi-quantitative studies on biological signal transduction and cellular structural dynamics involved in the physiology of healthy and disease states. Such studies focus on drug pharmacokinetics, receptor-mediated endocytosis, nuclear mechanobiology, viral infections, and cancer metastasis. In 1976, fluorescence recovery after photobleaching (FRAP), which involves the monitoring of fluorescence emission recovery within a photobleached spot, was developed. FRAP allowed investigators to probe two-dimensional (2D) diffusion of fluorescently-labelled biomolecules. Since then, FRAP has been refined through the advancements of optics, charged-coupled-device (CCD) cameras, confocal microscopes, and molecular probes. FRAP is now a highly quantitative tool used for transport and kinetic studies in the cytosol, organelles, and membrane of a cell. In this work, the authors intend to provide a review of recent advances in FRAP. The authors include epifluorescence spot FRAP, total internal reflection (TIR)/FRAP, and confocal microscope-based FRAP. The underlying mathematical models are also described. Finally, our understanding of coupled transport and kinetics as determined by FRAP will be discussed and the potential for future advances suggested.
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7
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Liu X, Wang Y, Effah CY, Wu L, Yu F, Wei J, Mao G, Xiong Y, He L. Endocytosis and intracellular RNAs imaging of nanomaterials-based fluorescence probes. Talanta 2022; 243:123377. [DOI: 10.1016/j.talanta.2022.123377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 03/02/2022] [Accepted: 03/09/2022] [Indexed: 12/12/2022]
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8
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Roden CA, Gladfelter AS. Design considerations for analyzing protein translation regulation by condensates. RNA (NEW YORK, N.Y.) 2022; 28:88-96. [PMID: 34670845 PMCID: PMC8675288 DOI: 10.1261/rna.079002.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
One proposed role for biomolecular condensates that contain RNA is translation regulation. In several specific contexts, translation has been shown to be modulated by the presence of a phase-separating protein and under conditions which promote phase separation, and likely many more await discovery. A powerful tool for determining the rules for condensate-dependent translation is the use of engineered RNA sequences, which can serve as reporters for translation efficiency. This Perspective will discuss design features to consider in engineering RNA reporters to determine the role of phase separation in translational regulation. Specifically, we will cover (i) how to engineer RNA sequence to recapitulate native protein/RNA interactions, (ii) the advantages and disadvantages for commonly used reporter RNA sequences, and (iii) important control experiments to distinguish between binding- and condensation-dependent translational repression. The goal of this review is to promote the design and application of faithful translation reporters to demonstrate a physiological role of biomolecular condensates in translation.
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Affiliation(s)
- Christine A Roden
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514, USA
| | - Amy S Gladfelter
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514, USA
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9
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Klimek R, Donlin-Asp PG, Polisseni C, Hanff V, Schuman EM, Heckel A. Visible light-activatable Q-dye molecular beacons for long-term mRNA monitoring in neurons. Chem Commun (Camb) 2021; 57:12683-12686. [PMID: 34780585 DOI: 10.1039/d1cc05664f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we present a new class of Q-dye molecular beacons (MBs) that can be locally activated with visible light in hippocampal neurons. Our novel architecture increases the available monitoring time for neuronal mRNA from several minutes to 14 hours, since a lower light-sampling rate is required for tracking.
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Affiliation(s)
- Robin Klimek
- Institute of Organic Chemistry and Chemical Biology, Goethe-University Frankfurt, Max-von-Laue-Straße 9, Frankfurt am Main 60438, Germany.
| | - Paul G Donlin-Asp
- Max Planck Institute for Brain Research, Max-von-Laue Str. 4, Frankfurt am Main 60438, Germany.
| | - Claudio Polisseni
- Max Planck Institute for Brain Research, Max-von-Laue Str. 4, Frankfurt am Main 60438, Germany.
| | - Vanessa Hanff
- Institute of Organic Chemistry and Chemical Biology, Goethe-University Frankfurt, Max-von-Laue-Straße 9, Frankfurt am Main 60438, Germany.
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Max-von-Laue Str. 4, Frankfurt am Main 60438, Germany.
| | - Alexander Heckel
- Institute of Organic Chemistry and Chemical Biology, Goethe-University Frankfurt, Max-von-Laue-Straße 9, Frankfurt am Main 60438, Germany.
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10
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Basyuk E, Rage F, Bertrand E. RNA transport from transcription to localized translation: a single molecule perspective. RNA Biol 2021; 18:1221-1237. [PMID: 33111627 PMCID: PMC8354613 DOI: 10.1080/15476286.2020.1842631] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 10/21/2020] [Accepted: 10/22/2020] [Indexed: 12/21/2022] Open
Abstract
Transport of mRNAs is an important step of gene expression, which brings the genetic message from the DNA in the nucleus to a precise cytoplasmic location in a regulated fashion. Perturbation of this process can lead to pathologies such as developmental and neurological disorders. In this review, we discuss recent advances in the field of mRNA transport made using single molecule fluorescent imaging approaches. We present an overview of these approaches in fixed and live cells and their input in understanding the key steps of mRNA journey: transport across the nucleoplasm, export through the nuclear pores and delivery to its final cytoplasmic location. This review puts a particular emphasis on the coupling of mRNA transport with translation, such as localization-dependent translational regulation and translation-dependent mRNA localization. We also highlight the recently discovered translation factories, and how cellular and viral RNAs can hijack membrane transport systems to travel in the cytoplasm.
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Affiliation(s)
- Eugenia Basyuk
- Institut de Génétique Humaine, CNRS-UMR9002, Univ Montpellier, Montpellier, France
- Present address: Laboratoire de Microbiologie Fondamentale et Pathogénicité, CNRS-UMR 5234, Université de Bordeaux, Bordeaux, France
| | - Florence Rage
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Univ Montpellier, Montpellier, France
| | - Edouard Bertrand
- Institut de Génétique Humaine, CNRS-UMR9002, Univ Montpellier, Montpellier, France
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Univ Montpellier, Montpellier, France
- Equipe Labélisée Ligue Nationale Contre Le Cancer, Montpellier, France
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11
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Moya-Ramírez I, Bouton C, Kontoravdi C, Polizzi K. High resolution biosensor to test the capping level and integrity of mRNAs. Nucleic Acids Res 2021; 48:e129. [PMID: 33152073 PMCID: PMC7736790 DOI: 10.1093/nar/gkaa955] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 09/22/2020] [Accepted: 10/08/2020] [Indexed: 11/21/2022] Open
Abstract
5′ Cap structures are ubiquitous on eukaryotic mRNAs, essential for post-transcriptional processing, translation initiation and stability. Here we describe a biosensor designed to detect the presence of cap structures on mRNAs that is also sensitive to mRNA degradation, so uncapped or degraded mRNAs can be detected in a single step. The biosensor is based on a chimeric protein that combines the recognition and transduction roles in a single molecule. The main feature of this sensor is its simplicity, enabling semi-quantitative analyses of capping levels with minimal instrumentation. The biosensor was demonstrated to detect the capping level on several in vitro transcribed mRNAs. Its sensitivity and dynamic range remained constant with RNAs ranging in size from 250 nt to approximately 2700 nt and the biosensor was able to detect variations in the capping level in increments of at least 20%, with a limit of detection of 2.4 pmol. Remarkably, it also can be applied to more complex analytes, such mRNA vaccines and mRNAs transcribed in vivo. This biosensor is an innovative example of a technology able to detect analytically challenging structures such as mRNA caps. It could find application in a variety of scenarios, from quality analysis of mRNA-based products such as vaccines to optimization of in vitro capping reactions.
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Affiliation(s)
- Ignacio Moya-Ramírez
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.,Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK
| | - Clement Bouton
- Department of Infectious Disease, Imperial College London, London W2 1NY, UK
| | - Cleo Kontoravdi
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Karen Polizzi
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.,Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK
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12
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Abstract
Labeling of nucleic acids is required for many studies aiming to elucidate their functions and dynamics in vitro and in cells. Out of the numerous labeling concepts that have been devised, covalent labeling provides the most stable linkage, an unrivaled choice of small and highly fluorescent labels and - thanks to recent advances in click chemistry - an incredible versatility. Depending on the approach, site-, sequence- and cell-specificity can be achieved. DNA and RNA labeling are rapidly developing fields that bring together multiple areas of research: on the one hand, synthetic and biophysical chemists develop new fluorescent labels and isomorphic nucleobases as well as faster and more selective bioorthogonal reactions. On the other hand, the number of enzymes that can be harnessed for post-synthetic and site-specific labeling of nucleic acids has increased significantly. Together with protein engineering and genetic manipulation of cells, intracellular and cell-specific labeling has become possible. In this review, we provide a structured overview of covalent labeling approaches for nucleic acids and highlight notable developments, in particular recent examples. The majority of this review will focus on fluorescent labeling; however, the principles can often be readily applied to other labels. We will start with entirely chemical approaches, followed by chemo-enzymatic strategies and ribozymes, and finish with metabolic labeling of nucleic acids. Each section is subdivided into direct (or one-step) and two-step labeling approaches and will start with DNA before treating RNA.
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Affiliation(s)
- Nils Klöcker
- Institute of Biochemistry, University of Muenster, Corrensstraße 36, D-48149 Münster, Germany.
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13
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Mao S, Ying Y, Wu R, Chen AK. Recent Advances in the Molecular Beacon Technology for Live-Cell Single-Molecule Imaging. iScience 2020; 23:101801. [PMID: 33299972 PMCID: PMC7702005 DOI: 10.1016/j.isci.2020.101801] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Nucleic acids, aside from being best known as the carrier of genetic information, are versatile biomaterials for constructing nanoscopic devices for biointerfacing, owing to their unique properties such as specific base pairing and predictable structure. For live-cell analysis of native RNA transcripts, the most widely used nucleic acid-based nanodevice has been the molecular beacon (MB), a class of stem-loop-forming probes that is activated to fluoresce upon hybridization with target RNA. Here, we overview efforts that have been made in developing MB-based bioassays for sensitive intracellular analysis, particularly at the single-molecule level. We also describe challenges that are currently limiting the widespread use of MBs and provide possible solutions. With continued refinement of MBs in terms of labeling specificity and detection accuracy, accompanied by new development in imaging platforms with unprecedented sensitivity, the application of MBs is envisioned to expand in various biological research fields.
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Affiliation(s)
- Shiqi Mao
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, China
| | - Yachen Ying
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, China
| | - Ruonan Wu
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, China
| | - Antony K. Chen
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, China
- Corresponding author
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14
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Markey FB, Parashar V, Batish M. Methods for spatial and temporal imaging of the different steps involved in RNA processing at single-molecule resolution. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1608. [PMID: 32543077 DOI: 10.1002/wrna.1608] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 12/26/2022]
Abstract
RNA plays a quintessential role as a messenger of information from genotype (DNA) to phenotype (proteins), as well as acts as a regulatory molecule (noncoding RNAs). All steps in the journey of RNA from synthesis (transcription), splicing, transport, localization, translation, to its eventual degradation, comprise important steps in gene expression, thereby controlling the fate of the cell. This lifecycle refers to the majority of RNAs (primarily mRNAs), but not other RNAs such as tRNAs. Imaging these processes in fixed cells and in live cells has been an important tool in developing an understanding of the regulatory steps in RNAs journey. Single-cell and single-molecule imaging techniques enable a much deeper understanding of cellular biology, which is not possible with bulk studies involving RNA isolated from a large pool of cells. Classic techniques, such as fluorescence in situ hybridization (FISH), as well as more recent aptamer-based approaches, have provided detailed insights into RNA localization, and have helped to predict the functions carried out by many RNA species. However, there are still certain processing steps that await high-resolution imaging, which is an exciting and upcoming area of research. In this review, we will discuss the methods that have revolutionized single-molecule resolution imaging in general, the steps of RNA processing in which these methods have been used, and new emerging technologies. This article is categorized under: RNA Export and Localization > RNA Localization RNA Methods > RNA Analyses in Cells RNA Interactions with Proteins and Other Molecules > Small Molecule-RNA Interactions.
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Affiliation(s)
- Fatu Badiane Markey
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
| | - Vijay Parashar
- Department of Medical and Molecular Sciences, University of Delaware, Newark, Delaware, USA
| | - Mona Batish
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA.,Department of Medical and Molecular Sciences, University of Delaware, Newark, Delaware, USA
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15
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16
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Visualization of Single mRNAs in Live Neurons. Methods Mol Biol 2019. [PMID: 31407277 DOI: 10.1007/978-1-4939-9674-2_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Transcription and post-transcriptional regulations are critical in gene expression. To study the spatiotemporal regulation of RNA inside a cell, techniques for high-resolution imaging of RNA have been developed. In this chapter, we describe RNA fluorescent labeling methods using MS2 and PP7 systems to detect single RNA molecules in live neurons. We use hippocampal neurons cultured from knock-in mouse models in which β-actin or Arc mRNAs are tagged with MS2 or PP7 stem-loops. Adeno-associated virus (AAV) or lentiviral vectors are used to express MS2 or PP7 capsid proteins fused with GFP in those neurons. Then, GFP-labeled RNAs in live neurons can be detected by epifluorescence microscopy, and their moving pathways can be analyzed using single-particle tracking software. For these processes, we introduce protocols for neuron culture, transfection, imaging, and particle tracking methods.
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17
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Stueland M, Wang T, Park HY, Mili S. RDI Calculator: An Analysis Tool to Assess RNA Distributions in Cells. Sci Rep 2019; 9:8267. [PMID: 31164708 PMCID: PMC6547641 DOI: 10.1038/s41598-019-44783-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 05/20/2019] [Indexed: 11/17/2022] Open
Abstract
Localization of RNAs to various subcellular destinations has emerged as a widely used mechanism that regulates a large proportion of transcripts in polarized cells. A number of methodologies have been developed that allow detection and imaging of RNAs at single-molecule resolution. However, methodologies to quantitatively describe RNA distributions are limited. Such approaches usually rely on the identification of cytoplasmic and nuclear boundaries which are used as reference points. Here, we describe an automated, interactive image analysis program that facilitates the accurate generation of cellular outlines from single cells and the subsequent calculation of metrics that quantify how a population of RNA molecules is distributed in the cell cytoplasm. We apply this analysis to mRNAs in mouse and human cells to demonstrate how these metrics can highlight differences in the distribution patterns of distinct RNA species. We further discuss considerations for the practical use of this tool. This program provides a way to facilitate and expedite the analysis of subcellular RNA localization for mechanistic and functional studies.
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Affiliation(s)
- Michael Stueland
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Tianhong Wang
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Hye Yoon Park
- Department of Physics and Astronomy, Seoul National University, Seoul, Korea
| | - Stavroula Mili
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA.
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